Conference Papers: C. R. Koch Mechanical Engineering University of Alberta

Author	Title	Year	Journal/Proceedings	Reftype	DOI/URL
Gordon, D., Sperling, E., Norouzi, A., Koch, C.R., Winkler, A. and Andert, J.	MPC implementation for HCCI Combustion using a Deep Neural Network based model [BibTeX]	2023	Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting , Edmonton, AB	conference
BibTeX: @conference{cics_DGI_2023, author = {D Gordon and E Sperling and A Norouzi and C R Koch and A Winkler and J Andert}, title = {MPC implementation for HCCI Combustion using a Deep Neural Network based model}, booktitle = {Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting , Edmonton, AB}, year = {2023} }
Gordon, D., Sperling, E., Norouzi, A., Koch, C.R., Winkler, A. and Andert, J.	Deep Neural Network based Performance and Emission Modelling [BibTeX]	2023	Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting , Edmonton, AB	conference	URL
BibTeX: @conference{cics_DG_2023, author = {D Gordon and E Sperling and A Norouzi and C R Koch and A Winkler and J Andert}, title = {Deep Neural Network based Performance and Emission Modelling}, booktitle = {Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting , Edmonton, AB}, year = {2023}, url = {/ ckoch/open_access/cics_DG_2019.pdf} }
McNally, J., Gordon, D., Sperling, E., Shahbakhti, M. and Koch, C.R.	Performance and Emission Investigation of Hydrogen Diesel Dual Fuel Combustion [BibTeX]	2023	Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting , Edmonton, AB	conference
BibTeX: @conference{cics_JM_2023, author = {J McNally and D Gordon and E Sperling and M Shahbakhti and C R Koch}, title = {Performance and Emission Investigation of Hydrogen Diesel Dual Fuel Combustion}, booktitle = {Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting , Edmonton, AB}, year = {2023} }
Winkler, A., Wang, W., Norouzi, A., Gordon, D., Koch, C.R. and Andert, J.	Integrating Recurrent Neural Networks into Model Predictive Control for Thermal Torque Derating of Electric Machines [BibTeX]	2023	IFAC World Conference 2023	unpublished
BibTeX: @unpublished{IFAC2023_AW, author = {Alexander Winkler and Weizhou Wang and Armin Norouzi and David Gordon and Charles Robert Koch and Jakob Andert}, title = {Integrating Recurrent Neural Networks into Model Predictive Control for Thermal Torque Derating of Electric Machines}, journal = {IFAC World Conference 2023}, year = {2023} }
Norouzi, A., Shahpouri, S., Gordon, D., Winkler, A., Nuss, E., Abel, D., Andert, J., Shahbakhti, M. and Koch, C.R.	Machine Learning Integrated with Model Predictive Control for Imitative Optimal Control of Compression Ignition Engines [BibTeX]	2022	IFAC-PapersOnLine Vol. 55(24), pp. 19-26	conference	DOI
BibTeX: @conference{Norouzi2022, author = {Armin Norouzi and Saeid Shahpouri and David Gordon and Alexander Winkler and Eugen Nuss and Dirk Abel and Jakob Andert and Mahdi Shahbakhti and Charles Robert Koch}, title = {Machine Learning Integrated with Model Predictive Control for Imitative Optimal Control of Compression Ignition Engines}, journal = {IFAC-PapersOnLine}, publisher = {Elsevier BV}, year = {2022}, volume = {55}, number = {24}, pages = {19--26}, doi = {https://doi.org/10.1016/j.ifacol.2022.10.256} }
Shahpouri, S., Norouzi, A., Hayduk, C., Rezaei, R., Koch, C. and Shahbakhti, M.	Modeling of a Single-Fuel Hydrogen Spark ignition and a Dual-FuelDiesel-Hydrogen Engines [BibTeX]	2022	Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting , Ottawa, ON	conference
BibTeX: @conference{cics_SS_2022, author = {S. Shahpouri and A. Norouzi and C. Hayduk and R. Rezaei and C.R. Koch and M. Shahbakhti}, title = {Modeling of a Single-Fuel Hydrogen Spark ignition and a Dual-FuelDiesel-Hydrogen Engines}, booktitle = {Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting , Ottawa, ON}, year = {2022} }
Aliramezani, M. and Koch, C.R.	Response characteristics of an amperometric NOx-O2 sensor at non diffusion-rate-determining conditions [BibTeX]	2021	SAE 2021-01-0678	conference	URL
BibTeX: @conference{sae2021_MA, author = {Masoud Aliramezani and Charles Robert Koch}, title = {Response characteristics of an amperometric NOx-O2 sensor at non diffusion-rate-determining conditions}, journal = {SAE 2021-01-0678}, year = {2021}, note = {SAE 2021-01-0678}, url = {/ ckoch/open_access/sae2021_MA.pdf} }
Shahpouri, S., Norouzi, A., Hayduk, C., Rezaei, R., Shahbakhti, M. and Koch, C.R.	Soot Emission Modeling of a Compression Ignition Engine Using Machine Learning [Abstract] [BibTeX]	2021	IFAC-PapersOnLine Vol. 54(20)Modeling, Estimation and Control Conference MECC 2021, pp. 826-833	conference	DOI URL
Abstract: Control of real driving soot emissions in diesel vehicles requires accurate predictive models for engine-out soot emissions. This paper presents an innovative modeling approach that combines a physics-based model and a black-box model to predict soot from a 4.5-liter compression ignition engine under varying load and speed conditions. The physical model is based on an experimentally validated 1D engine model in GT-power. In contrast, the black-box model is designed by investigating different machine learning approaches, including a Bayesian neural network (BNN), support vector machine (SVM), regression tree, and an ensemble of regression tree. The experimental data from running the engine at 219 load and speed conditions are collected and used for training and testing the soot model. The least absolute shrinkage and selection operator (LASSO) feature selection method is used on the GT model outputs to find the most critical parameters in soot prediction. The grey-box modeling results are compared with those from the black-box as well as the physical model. The results show that the grey-box SVM and black-box single hidden layer BNN method provide the best performance with a coefficient of determination (R2) of 0.95. For most cases, grey-box models outperform the black-box models with the same Machine Learning (ML) algorithm by comparing R2 of the test data, but this difference becomes negligible when a single hidden layer neural network is used.
BibTeX: @conference{Shahpouri2021, author = {Shahpouri, Saeid and Norouzi, Armin and Hayduk, Christopher and Rezaei, Reza and Shahbakhti, Mahdi and Koch, Charles Robert}, title = {Soot Emission Modeling of a Compression Ignition Engine Using Machine Learning}, booktitle = {Modeling, Estimation and Control Conference MECC 2021}, journal = {IFAC-PapersOnLine}, year = {2021}, volume = {54}, number = {20}, pages = {826--833}, url = {https://www.sciencedirect.com/science/article/pii/S2405896321023181}, doi = {https://doi.org/10.1016/j.ifacol.2021.11.274} }
Aliramezani, M., Norouzi, A. and Koch, C.R.	Support vector machine for a diesel engine performance and NOx emission control-oriented model [BibTeX]	2020	IFAC-PapersOnLine Vol. 53(2), pp. 13976-13981	conference	DOI URL
BibTeX: @conference{Aliramezani2020, author = {Masoud Aliramezani and Armin Norouzi and Charles Robert Koch}, title = {Support vector machine for a diesel engine performance and NOx emission control-oriented model}, journal = {IFAC-PapersOnLine}, publisher = {IFAC-PapersOnLine, Elsevier BV}, year = {2020}, volume = {53}, number = {2}, pages = {13976--13981}, url = {/ ckoch/open_access/Aliramezani2020.pdf}, doi = {https://doi.org/10.1016/j.ifacol.2020.12.916} }
Norouzi, A., Gordon, D.C., Aliramezani, M. and Koch, C.R.	Machine Learning-based Diesel Engine-Out NOx Reduction Using a plug-in PD-type Iterative Learning Control [BibTeX]	2020	2020 IEEE Conference on Control Technology and Applications (CCTA), pp. 450-455	conference	URL
BibTeX: @conference{CCTA_2020, author = {Armin Norouzi and David Carl Gordon and Masoud Aliramezani and Charles Robert Koch}, title = {Machine Learning-based Diesel Engine-Out NOx Reduction Using a plug-in PD-type Iterative Learning Control}, booktitle = {2020 IEEE Conference on Control Technology and Applications (CCTA)}, year = {2020}, pages = {450--455}, url = {/ ckoch/open_access/CCTA_2020.pdf} }
Norouzi, A. and Koch, C.R.	Integration of PD-type Iterative Learning Control with Adaptive Sliding Mode Control [BibTeX]	2020	IFAC-PapersOnLine Vol. 53(2), pp. 6213-6218	conference	DOI
BibTeX: @conference{Norouzi2020, author = {Armin Norouzi and Charles Robert Koch}, title = {Integration of PD-type Iterative Learning Control with Adaptive Sliding Mode Control}, journal = {IFAC-PapersOnLine}, publisher = {IFAC-PapersOnLine, Elsevier BV}, year = {2020}, volume = {53}, number = {2}, pages = {6213--6218}, doi = {https://doi.org/10.1016/j.ifacol.2020.12.1717} }
Xie, J., Koch, C.R. and Dubljevic, S.	Internal Model Controller Design of Linearized Ginzburg-Landau Equation [BibTeX]	2020	IFAC-PapersOnLine Vol. 53(2), pp. 7728-7733	conference	DOI
BibTeX: @conference{Xie2020, author = {Junyao Xie and Charles Robert Koch and Stevan Dubljevic}, title = {Internal Model Controller Design of Linearized Ginzburg-Landau Equation}, journal = {IFAC-PapersOnLine}, publisher = {IFAC-PapersOnLine, Elsevier BV}, year = {2020}, volume = {53}, number = {2}, pages = {7728--7733}, doi = {https://doi.org/10.1016/j.ifacol.2020.12.1523} }
Aliramezani, M., Norouzi, A. and Koch, C.R.	A control oriented diesel engine NOx emission model for on board diagnostics and engine control with sensor feedback [BibTeX]	2019	Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting , Kelowna, BC	conference	URL
BibTeX: @conference{cics_MA_2019, author = {Masoud Aliramezani and Armin Norouzi and Charles Robert Koch}, title = {A control oriented diesel engine NOx emission model for on board diagnostics and engine control with sensor feedback}, booktitle = {Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting , Kelowna, BC}, year = {2019}, url = {/ ckoch/open_access/cics_MA_2019.pdf} }
Gordon, D., Koch, C., Wouters, C., Lehrheuer, B., Pischinger, S., Wick, M. and Andert, J.	NVO peak pressure based in-cycle control for HCCI combustion using direct water injection [BibTeX]	2019	Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting , Kelowna, BC	conference	URL
BibTeX: @conference{cics_DG_2019, author = {D. Gordon and C.R. Koch and C. Wouters and B. Lehrheuer and S. Pischinger and M. Wick and J. Andert}, title = {NVO peak pressure based in-cycle control for HCCI combustion using direct water injection}, booktitle = {Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting , Kelowna, BC}, year = {2019}, url = {/ ckoch/open_access/cics_DG_2019.pdf} }
Gordon, D., Wouters, C., Kinoshita, S., Wick, M., Lehrheuer, B., Andert, J., Pischinger, S. and Koch, C.R.	HCCI Combustion Stability Improvement Using a Rapid Ignition System [BibTeX]	2019	Symposium of Combustion Control, Aachen Germany	conference	URL
BibTeX: @conference{SCC_DG_2019, author = {David Gordon and Christian Wouters and Shota Kinoshita and Maximilian Wick and Bastian Lehrheuer and Jakob Andert and Stefan Pischinger and Charles R Koch}, title = {HCCI Combustion Stability Improvement Using a Rapid Ignition System}, booktitle = {Symposium of Combustion Control, Aachen Germany}, year = {2019}, url = {/ ckoch/open_access/SCC_DG_2019.pdf} }
Norouzi, A., Ebrahimi, K. and Koch, C.R.	Integral Discrete-time Sliding Mode Control of Homogeneous Charge Compression Ignition (HCCI) Engine Load and Combustion Timing [BibTeX]	2019	9th IFAC Int. Sym. on Advances in Automotive Control, Orleons, France	conference
BibTeX: @conference{AAC_AN_2019, author = {Armin Norouzi and Khashayar Ebrahimi and Charles Robert Koch}, title = {Integral Discrete-time Sliding Mode Control of Homogeneous Charge Compression Ignition (HCCI) Engine Load and Combustion Timing}, booktitle = {9th IFAC Int. Sym. on Advances in Automotive Control, Orleons, France}, year = {2019} }
Norouzi, A. and Koch, C.R.	Robotic Manipulator Control Using PD-type Fuzzy Iterative Learning Control [BibTeX]	2019	Canadian Conference of Electrical and Computer Engineering	conference	URL
BibTeX: @conference{CCECE_AN_2019, author = {A. Norouzi and C. R. Koch}, title = {Robotic Manipulator Control Using PD-type Fuzzy Iterative Learning Control}, booktitle = {Canadian Conference of Electrical and Computer Engineering}, year = {2019}, url = {/ ckoch/open_access/CCECE_AN_2019.pdf} }
Ebrahimi, K. and Koch, C.R.	Symmetric Negative Valve Overlap effects on energy distribution of a single cylinder HCCI engine [Abstract] [BibTeX]	2018	SAE Paper 2018-01-1250, pp. 15	conference	URL
Abstract: The effects of Variable Valve Timing (VVT) on Homogeneous Charge Compression Ignition (HCCI) engine energy distribution and waste heat recovery are investigated using a fully flexible Electromagnetic Variable Valve Timing (EVVT) system. The experiment is carried out in a single cylinder, 657 cc, port fuel injection engine fueled with n-heptane. Exergy analysis is performed to understand the relative contribution of different loss mechanisms in HCCI engines and how VVT changes these contributions. It is found that HCCI engine brake thermal efficiency, the Combined Heat and Power (CHP) power to heat ratio, the first and the second law efficiencies are improved with proper valve timing. Further analysis is preformed by applying the first and second law of thermodynamics to compare HCCI energy and exergy distribution to Spark Ignition (SI) combustion using Primary Reference Fuel (PRF). HCCI demonstrates higher fuel efficiency and power to heat and energy loss ratios compared to SI. The results are applicable for the development of micro-CHP systems using an HCCI engine operating at a constant engine speed with varying loads.
BibTeX: @conference{Ebrahimi2018_sae, author = {K. Ebrahimi and C. R. Koch}, title = {Symmetric Negative Valve Overlap effects on energy distribution of a single cylinder HCCI engine}, booktitle = {SAE Paper 2018-01-1250}, year = {2018}, pages = {15}, url = {/ ckoch/open_access/Ebrahimi2018_sae.pdf} }
Ebrahimi, K. and Koch, C.R.	Real-time Control of HCCI Engine Using Model Predictive Control [BibTeX]	2018	2018 American Controls Conference (ACC), Milwakee, USA, pp. 1622-1628	conference	URL
BibTeX: @conference{Ebrahimi_acc2018, author = {K. Ebrahimi and C. R. Koch}, title = {Real-time Control of HCCI Engine Using Model Predictive Control}, booktitle = {2018 American Controls Conference (ACC), Milwakee, USA}, year = {2018}, pages = {1622-1628}, url = {/ ckoch/open_access/Ebrahimi_acc2018.pdf} }
Klikach, R., Ebrahimi, K. and Koch, C.R.	Experimental Investigation and Analysis of Natural Gas RCCI on a Modifed GDI Engine using NVO [BibTeX]	2018	Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting , Toronto, pp. 6	conference	URL
BibTeX: @conference{Klikach2018cics, author = {R. Klikach and K. Ebrahimi and C. R. Koch}, title = {Experimental Investigation and Analysis of Natural Gas RCCI on a Modifed GDI Engine using NVO}, booktitle = {Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting , Toronto}, year = {2018}, pages = {6}, url = {/ ckoch/open_access/Klikach2018cics.pdf} }
Symko, G., Aliramezani, M., Koch, C.R. and Hayes, R.E.	Axial insulation rings - testing and simulation of pressure drop and temperature transients in engine exhaust catalysts [BibTeX]	2018	Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting , Toronto, pp. 6	conference	URL
BibTeX: @conference{Symko2018cics, author = {G. Symko and M. Aliramezani and C. R. Koch and R. E. Hayes}, title = {Axial insulation rings - testing and simulation of pressure drop and temperature transients in engine exhaust catalysts}, booktitle = {Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting , Toronto}, year = {2018}, pages = {6}, url = {/ ckoch/open_access/Symko2018cics.pdf} }
Aliramezani, M., Ebrahimi, K., Koch, C.R. and Hayes, R.E.	Investigating the effect of temperature on NOx sensor cross sensitivity to ammonia using a simplified physic-based model [BibTeX]	2017	Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting , Montreal, pp. 6	conference	URL
BibTeX: @conference{Airamezani2017cics, author = {M. Aliramezani and K. Ebrahimi and C. R. Koch and R. E. Hayes}, title = {Investigating the effect of temperature on NOx sensor cross sensitivity to ammonia using a simplified physic-based model}, booktitle = {Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting , Montreal}, year = {2017}, pages = {6}, url = {/ ckoch/open_access/Airamezani2017cics.pdf} }
Nazaripoor, H., Khorshidi, B., Koch, C.R. and Sadrzadeh, M.	Electrohydrodynamic instabilities in heated thin liquid films [Abstract] [BibTeX]	2017	7th International Colloids Conference, Sitges, Spain	conference
Abstract: Dynamic and instability in thin liquid films have gained extensive attention as they present in nature and many technological applications like in our eye's cornea, liquid and foam emulsions, coatings and soft lithography. Instabilities in thin liquid films can be generated applying external forces like mechanical, electrical and thermal forces. For the ultrathin films of nanometer thickness range, the role of intermolecular interactions (non-polar and polar) becomes significant. More recently these liquid films have been used in soft lithography, and a broad variety of micro and nano-sized features are generated using the electrically induced perturbation method, so-called electrohydrodynamic (EHD) lithography. In this method, a thin polymer film (with a thickness of h) is spin coated on an electrically conductive substrate and confined with a mounted conductive substrate at a distance of d, then heated to above the film's glass transition temperature (T>Tg). The gap between the film and the top substrate filled with air or any other film layer. Applying electric field induces electrostatic Maxwell stress at the film interface that results in the formation of patterns. Depending on electrical and geometrical properties of this system, pillars, bicontinuous, holes and roll-like structure can form over particular annealing time. In the EHD patterning process, it is assumed that the pattern formation process is performed in an isothermal condition. However, the presence of thermal gradient across the film can generate thermocapillary (TC) forces at the interface in addition to the electrical forces. In this study, the governing equations re-formulated for the EHD instabilities of the heated liquid film using long-wave approximation. Linear stability analysis and non-linear analysis, using numerical simulation, performed to investigate the thermal and electrical properties of film and the bounding layer on the dynamics, instability, and pattern formation process. Results showed the formation of more features with smaller size when the TC forces added to the electrical forces.
BibTeX: @conference{Nazaripoor_icc2017, author = {H. Nazaripoor and B. Khorshidi and C. R. Koch and M. Sadrzadeh}, title = {Electrohydrodynamic instabilities in heated thin liquid films}, booktitle = {7th International Colloids Conference, Sitges, Spain}, year = {2017}, note = {One page poster} }
Wang, Z., Flynn, M.R. and Koch, C.R.	Model order reduction and boundary control of incompressible Boussinesq flow [Abstract] [BibTeX]	2017	Society of Canada, pp. 9	conference
Abstract: The time evolution of a two dimensional incompressible, density stratified, Boussinesq flow in a rectangular cavity is numerically simulated for a range of parameters. Boundary control is then implemented along the upper boundary by adjusting the fluid temperature. More specifically, the top boundary condition of the cavity is a fixed function of space that is modulated by the control input. The resulting numerical simulation for the fluid density and velocity is computed using finite differences in the vertical direction and a spectral method in the horizontal direction. To develop the control strategy, the flow is simulated and a sequence of snapshots of the density and velocity fields are collected. Then, a reduced order modelling method suitable for a linear quadratic regulator (LQR) of the Boussinesq flow is developed using the proper orthogonal decomposition (POD)/Galerkin approach. The reduced order model (ROM) is obtained by projecting the governing equations of the flow onto the sub space spanned by a finite number of basis functions obtained using the method of snapshots. For the flow in question, the POD method based on the snapshots yields six POD modes which capture 99% of the flow energy. The feasibility of this method is assessed using a LQR boundary controller that is designed based on the reduced order model. The cost functional which is minimized in the LQR control design is defined to be the norm of the difference between the actual density field and the desired density field in the cavity. The weighting parameter of the cost functional is found to play a critical role in the process of controller design. The effectiveness of the control is evaluated under both steady and transient flow conditions. In conclusion, a relatively simple feedback control scheme applied on the boundary of a turbulent flow improves the performance in regulating the density field to its desired final state compared to open-loop control.
BibTeX: @conference{Wang-Z_cfd_2017, author = {Zichuan Wang and Morris R Flynn and Charles Robert Koch}, title = {Model order reduction and boundary control of incompressible Boussinesq flow}, booktitle = {Society of Canada}, year = {2017}, pages = {9} }
Aliramezani, M., Ebrahimi, K., Koch, C.R. and Hayes, R.E.	NOx sensor ammonia cross sensitivity analysis using a simplified physic-based model [Abstract] [BibTeX]	2016	Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting , Waterloo ON, pp. 6	conference	URL
Abstract: A simplified physic-based NOx sensor model is developed to remove ammonia cross sensitivity from production NOx sensors. A linear model is used to consider the effect of ammonia contamination on the NOx sensor output signal using a cross sensitivity factor. The effect of temperature on NOx sensor cross sensitivity to ammonia is then investigated by simulating NH3 oxidation inside the sensor. The model considers the effect of temperature on cross sensitivity based on three global reactions. N2O, NO and NO2 are considered as productions of NH3 oxidation inside the sensor. Finally, a relation is derived for cross sensitivity factor in terms of concentration of N2O, NO and NO2.This model provides a simplified physic-based model for detailed NOX sensor cross sensitivity analysis.
BibTeX: @conference{Airamezani2016cics, author = {M. Aliramezani and K. Ebrahimi and C. R. Koch and R. E. Hayes}, title = {NOx sensor ammonia cross sensitivity analysis using a simplified physic-based model}, booktitle = {Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting , Waterloo ON}, year = {2016}, pages = {6}, url = {/ ckoch/open_access/Airamezani2016cics.pdf} }
Aliramezani, M., Koch, C.R. and Hayes, R.E.	Estimating tailpipe NOx concentration using a dynamic NOx/ammonia cross sensitivity model coupled to a three state control oriented SCR model [Abstract] [BibTeX]	2016	IFAC-PapersOnLine Vol. 49(11)IFAC Advances in Automotive Controls Conference (AAC), Sweden, pp. 8-13	conference	URL
Abstract: A dynamic NO_x sensor model is developed to remove ammonia cross sensitivity from production NO_x sensors mounted downstream of Diesel-engine selective catalytic reduction (SCR) systems. The model is validated for large amounts of ammonia slip during different engine transients. A three-state nonlinear control oriented SCR model is also developed to predict the NH_3 concentration downstream of the SCR (NH_3 slip). NH_3 slip is then used as an input for modeling the cross sensitivity of a production NO_x sensor and calculating the actual NO_x concentration in the presence of NH_3 contamination. The cross sensitivity is considered to be a function of temperature, normalized ammonia slip rate (NASR) and time. The validation results show that the developed model has an acceptable accuracy for the actual NO_x concentration downstream of the SCR. This model should be of utility for engine emission control strategies such as SCR control.
BibTeX: @conference{Aliramezani2016aac, author = {M. Aliramezani and C. R. Koch and R. E. Hayes}, title = {Estimating tailpipe NOx concentration using a dynamic NOx/ammonia cross sensitivity model coupled to a three state control oriented SCR model}, booktitle = {IFAC Advances in Automotive Controls Conference (AAC), Sweden}, journal = {IFAC-PapersOnLine}, publisher = {Elsevier}, year = {2016}, volume = {49}, number = {11}, pages = {8--13}, url = {/ ckoch/open_access/Aliramezani2016aac.pdf} }
Chen, K., Koch, C.R. and Olfert, J.S.	Development of a Universal Aerosol Conditioning Device for Particle Measurement. [BibTeX]	2016	35th Annual American Association for Aerosol Research Conference	conference
BibTeX: @conference{Kerry-aaar-2016, author = {K. Chen and C. R. Koch and J. S. Olfert}, title = {Development of a Universal Aerosol Conditioning Device for Particle Measurement.}, booktitle = {35th Annual American Association for Aerosol Research Conference}, year = {2016} }
Ebrahimi, K., Aliramezani, M. and Koch, C.R.	An HCCI Control Oriented Model that Includes Combustion Efficiency [Abstract] [BibTeX]	2016	IFAC-PapersOnLine Vol. 49(11)IFAC Advances in Automotive Controls Conference (AAC), Sweden, pp. 327-332	conference	URL
Abstract: A control oriented model that includes combustion timing, engine load and combustion efficiency for Homogeneous Charge Compression Ignition (HCCI) engines is developed. In HCCI engines, a lean homogeneous air-fuel mixture auto-ignites due to compression and combustion occurs at lower temperatures compared to spark ignition and diesel engines. The low HCCI combustion temperature results in low NO_X level, however unburnt HC and CO levels are high. Higher thermal efficiencies are realized for higher combustion efficiencies when combustion timings is appropriate. First, the effects of valve timing and fueling rate on combustion efficiency are investigated experimentally. Then, the influence of combustion efficiency on HC and CO emissions is studied. A physics based control oriented model of HCCI engine combustion efficiency and emission for future control design is developed. This model includes the effect of trapped residual gas and fueling rate on combustion timing and output power. The developed model has acceptable accuracy for combustion timing, load and combustion efficiency prediction compared to experimental data. This model is useful for combustion timing and load control in HCCI engines while simultaneously considering the constraints of combustion efficiency and emission.
BibTeX: @conference{Ebrahimi2016aac, author = {K. Ebrahimi and M. Aliramezani and C. R. Koch}, title = {An HCCI Control Oriented Model that Includes Combustion Efficiency}, booktitle = {IFAC Advances in Automotive Controls Conference (AAC), Sweden}, journal = {IFAC-PapersOnLine}, publisher = {Elsevier}, year = {2016}, volume = {49}, number = {11}, pages = {327--332}, url = {/ ckoch/open_access/Ebrahimi2016aac.pdf} }
Slepicka, C. and Koch, C.R.	Iterative Learning Controller on Dual-fuel Control of Homogeneous Charge Compression Ignition [Abstract] [BibTeX]	2016	IFAC-PapersOnLine Vol. 49(11)IFAC Advances in Automotive Controls Conference (AAC), Sweden, pp. 347-352	conference	URL
Abstract: An Iterative Learning Controller (ILC) is used to control a dual-fuel Homogeneous Charge Compression (HCCI) engine. The engine is a CFR engine with a modified head for in-cylinder pressure measurement ports and was operated at 100^circC intake heating, 800 RPM and a compression ratio of 11:1. To control combustion timing and load, the amount of iso-octane and n-heptane injected into the manifold are used as inputs. The metrics used for combustion timing and load are CA50, crank angle when 50% of the fuel is burned, and gross IMEP, respectively. Using these inputs and outputs a system identification was performed using an ARMAX model. This model is then used to generate a norm optimal control. The norm optimal control is compared to a model-less control strategy that involve populating the off-diagonal of the learning matrix using a Jacobian estimate inverse. Both systems are used to follow a reference trajectory involving a step input in IMEP then CA50. The model-less control outperforms the norm optimal in both convergence speed and final iteration error. Application of non-causal filters within the iteration is also tested using a zero-phase filter and a Gaussian filter. The zero-phase has faster convergence than either the Gaussian or filter-less and has better final iteration error. This gives the best ILC control as model-less with zero-phase filter. This control is then compared to two PI controllers. It was found that the ILC outperforms the PI controllers after 3 iterations.
BibTeX: @conference{Slepicka2016aac, author = {C. Slepicka and C. R. Koch}, title = {Iterative Learning Controller on Dual-fuel Control of Homogeneous Charge Compression Ignition}, booktitle = {IFAC Advances in Automotive Controls Conference (AAC), Sweden}, journal = {IFAC-PapersOnLine}, publisher = {Elsevier}, year = {2016}, volume = {49}, number = {11}, pages = {347--352}, url = {/ ckoch/open_access/Slepicka2016aac.pdf} }
Ebrahimi, K. and Koch, C.R.	Model Predictive Control for Combustion Timing and Load Control in HCCI engines [Abstract] [BibTeX]	2015	SAE Paper 2015-01-0822, pp. 15	conference	URL
Abstract: A Model Predictive Control (MPC) strategy for Homogeneous Charge Compression Ignition (HCCI) combustion timing and output work control that takes into account actuator constraints is designed. The MPC is based on the linearized version of a nonlinear Control Oriented Model (COM). The COM for the HCCI engine has combustion timing and engine load as outputs and valve timing and fueling rate as the the inputs.The COM model is developed and validated and found to be accurate enough for control purposes and can be implemented in real-time. A Detailed Physical Model (DPM) is used to test the controller using the valve timing and fueling rate as constrained actuators. Constraints on combustion timing and output work are also considered to prevent engine knock or misfire. The simulation results show that the developed controller works over a range of conditions and can maintain HCCI combustion timing and load in their desired values.
BibTeX: @conference{Ebrahimi2015_sae, author = {K. Ebrahimi and C. R. Koch}, title = {Model Predictive Control for Combustion Timing and Load Control in HCCI engines}, booktitle = {SAE Paper 2015-01-0822}, year = {2015}, pages = {15}, url = {/ ckoch/open_access/Ebrahimi2015_sae.pdf} }
Nobes, D.S., Bussiere, M. and Koch, C.R.	The Vortex Field Behind A Single And Tandem Flapping Airfoil [BibTeX]	2015	10th Pacific Symp on Flow Visualization and Image Processing, pp. 19	conference	URL
BibTeX: @conference{Buss_2015, author = {D. S. Nobes and M. Bussiere and C. R. Koch}, title = {The Vortex Field Behind A Single And Tandem Flapping Airfoil}, booktitle = {10th Pacific Symp on Flow Visualization and Image Processing}, year = {2015}, pages = {19}, note = {Naples}, url = {/ ckoch/open_access/Buss_2015.pdf} }
Ebrahimi, K., Schramm, A. and Koch, C.R.	Feedforward/Feedback Control of HCCI combustion timing [Abstract] [BibTeX]	2014	2014 American Controls Conference (ACC), Portland, USA, pp. 6	conference	URL
Abstract: Homogeneous Charge Compression Ignition (HCCI) engines have the advantage of low Nitrogen Oxides (NO_x) and soot emissions. In HCCI engines, a lean premixed air-fuel mixture is compressed until the temperature is high enough for combustion to occur. HCCI engines have a limited operating range and are limited by knock at high loads and misfire at low loads. They are without a direct source to initiate ignition so HCCI requires combustion timing control. Some of the factors that affect HCCI combustion timing are mixture composition, pressure and temperature at the time of inlet valve closing. One effective way to control HCCI combustion timing is Variable Valve Timing (VVT). VVT changes the amount of trapped residual gas and the effective compression ratio. These factors have a strong effect on HCCI combustion timing. One main advantage of VVT is that it is fast enough to handle rapid transients. Based on a simplified control oriented model that models the effect of trapped residual gas on combustion timing, a Feedforward/Feedback controller is designed for HCCI combustion timing control . The controller requires feedforward information of the valve timing and feedback information of the combustion timing. This controller tracks the desired combustion timing trajectory both in simulation and experiment by modulating the trapped residual gas using VVT actuation.
BibTeX: @conference{Ebrahimi_acc2014, author = {K. Ebrahimi and Alexander Schramm and C. R. Koch}, title = {Feedforward/Feedback Control of HCCI combustion timing}, booktitle = {2014 American Controls Conference (ACC), Portland, USA}, year = {2014}, pages = {6}, url = {/ ckoch/open_access/Ebrahimi_acc2014.pdf} }
Ebrahimi, K., Schramm, A. and Koch, C.R.	Effects of Asymmetric Valve Timing with Constant NVO Duration on HCCI Engine Combustion Characteristics [Abstract] [BibTeX]	2014	Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting , Windsor, ON, pp. 6	conference	URL
Abstract: Homogeneous Charge Compression Ignition (HCCI) engine combustion characteristics are investigated by changing the amount of trapped residual gas and compression ratio cycle-by-cycle by keeping the Negative Valve Overlap (NVO) duration constant and only varying the Exhaust Valve Closing (EVC) and Intake Valve Opening (IVO) timings. Three different NVO durations are tested. Rate of heat release, which is calculated from the in-cylinder pressure trace, and the exhaust gas emission measurements information are used to examine the HCCI engine combustion features. Combustion timing and burn duration are significantly affected by the level of trapped residual gas with this valve timing strategy. The measurements indicate that fuel efficiency, output torque and Indicated Mean Effective Pressure (IMEP) are improved when IVO and EVC timings are advanced simultaneously with constant NVO duration. CO concentration is reduced with the retarded EVC and IVO timings while CO2 concentration reaches its minimum with symmetric NVO.
BibTeX: @conference{CICS2014, author = {K. Ebrahimi and A. Schramm and C. R. Koch}, title = {Effects of Asymmetric Valve Timing with Constant NVO Duration on HCCI Engine Combustion Characteristics}, booktitle = {Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting , Windsor, ON}, year = {2014}, pages = {6}, url = {/ ckoch/open_access/CICS2014.pdf} }
Nazaripoor, H., Koch, C.R. and Bhattacharjee, S.	Dynamics Of Thin Liquid Bilayers Subjected To An External Electric Field [Abstract] [BibTeX]	2014	(1)ASME Int Conf. Montreal Ca, pp. 7	conference	URL
Abstract: Spatiotemporal evolution of liquid-liquid interface leading to dewetting and pattern formation is investigated for thin liquid bilayeres subjected to the long range electrostatic force and the short range van der Waals forces. Based on the 2D weakly non-linear thin film equation three dimensional structure evolution is numerically simulated. A combined finite difference for the spatial dimensions and an adaptive time step ODE solver is used to solve the governing equation. For initially non-wetting surfaces, the stabilizing effects of viscosity and interfacial tension and the destabilizing effect of the Hamaker constant are investigated. Electrostatic interaction is calculated analytically for both perfect dielectric-perfect dielectric and ionic conductive-perfect dielectric bilayers. Ionic conductive-perfect dielectric bi-layers based on the electric permittivity ratio of layers are found to be stabilized or deformed in response to the applied externalelectric field.
BibTeX: @conference{Hadi_asme_2014, author = {Nazaripoor, H. and Koch, Charles R. and Bhattacharjee, Subir}, title = {Dynamics Of Thin Liquid Bilayers Subjected To An External Electric Field}, booktitle = {ASME Int Conf. Montreal Ca}, year = {2014}, number = {1}, pages = {7}, url = {/ ckoch/open_access/Hadi_asme_2014.pdf} }
Sabbagh, R., Lipsett, M.G., Koch, C.R. and Nobes, D.S.	Theoretical And Experimental Study Of Hydrocyclone Performance And Equivalent Settling Area [Abstract] [BibTeX]	2014	(1)ASME Int Conf. Montreal Ca	conference	URL
Abstract: Predicting the performance of a solid-liquid separation process can help in comparing different separators for selection and design. This can be applied to hydrocyclone technology which is used widely in industry due to being an inexpensive device that is easy to operate and maintain and which has no moving parts. Environmental concerns and technological issues in separation processes are motivating the design of higher ?efficiency systems with less capital and operating costs. There is a need therefore for, methods to compare different ?separation technologies. In spite of extensive research into hydrocyclone performance, a mathematical model that can predict the performance of a hydrocyclone for comparison with other centrifugal separators is rare in the literature. The main objective of this research is to apply theoretical and ?experimental approaches to study hydrocyclone performance ?in order to propose an applicable separation performance ?model that represents the whole hydrocyclone operating range. A mathematical model is developed to explore the performance of the separator and to predict the hydrocyclone's equivalent area as compared to a continuous gravity settling tank. A performance chart that can be used for selection and design of hydrocyclones is the result of the model.
BibTeX: @conference{Sabbagh_asme_2014, author = {Sabbagh, R. and Lipsett, M. G. and Koch, Charles R. and Nobes, David S.}, title = {Theoretical And Experimental Study Of Hydrocyclone Performance And Equivalent Settling Area}, booktitle = {ASME Int Conf. Montreal Ca}, year = {2014}, number = {1}, note = {IMECE2014-37482}, url = {/ ckoch/open_access/Sabbagh_asme_2014.pdf} }
Sabbagh, R., Lipsett, M.G., Koch, C.R. and Nobes, D.S.	Hydrocyclone Performance Comparison under the influence of underflow pumping [Abstract] [BibTeX]	2014	European Conference on Fluid-Particle Separation (FPS) October 2014, Lyon, Fr, pp. 2	conference	URL
Abstract: A mathematical model is developed to predict the performance of hydrocyclones for solid-liquid separation. This model is based on residence time theory combined with estimation of average vertical velocity according to locus of zero vertical velocity resulted from equilibrium orbit theory for hydrocyclones. The tangential velocity component is also related to that radial distance of inlet particle from the hydrocyclone centerline. This mathematical model is then used to develop the equivalent area factor that indicates the area of a gravity settling time with the same separation performance as in the hydrocyclone. A performance chart is developed from the model and is compared with literature. It is shown that the chart obtained in the current study is in good agreement with experimental data. This performance chart can be used now as a guideline for selecting and design of hydrocyclones. An experimental setup is also designed for validating the model and resulted chart.
BibTeX: @conference{Sabbagh_FPS_2014, author = {R. Sabbagh and M. G. Lipsett and C. R. Koch and D. S. Nobes}, title = {Hydrocyclone Performance Comparison under the influence of underflow pumping}, journal = {European Conference on Fluid-Particle Separation (FPS) October 2014, Lyon, Fr}, year = {2014}, pages = {2}, url = {/ ckoch/open_access/Sabbagh_FPS_2014.pdf} }
Bullock, D., Schramm, A., Momenimovahed, A., Koch, C.R. and Olfert, J.S.	Effects of Transient Valve Timing on Particulate Emission Concentration of a Homogeneous Charge Compression Ignition Engine [Abstract] [BibTeX]	2013	Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting , Quebec City, QB, pp. 6	conference	URL
Abstract: To quantify the particle emissions from a Homogeneous Charge Compression Ignition (HCCI) engine, a fast-response differential mobility spectrometer (DMS) is used during transient operation to measure momentary changes in particle concentration and size distribution. The DMS has a time response of 500 ms (10-90% rise time) and a sample rate of 2 Hz is used while the engine is operated at approximately 820 rpm or 7 cycles/s. A single cylinder engine with electromagnetic valves is used to test the effect of changing valve timing on particle emissions. During steady-state operation of the single cylinder engine at both 60deg and 180deg of symmetric negative valve overlap (NVO), average particle emissions of 6.0x10^7 and 5.7x10^7 cm-3 respectively are measured. These values agree well within error. The geometric mean diameters (GMD) of both tests are also comparable at 15 nm and 16 nm, respectively. Particulate emissions are then recorded while switching the valve timing between 60deg and 180deg NVO in order to see the effect of a change in engine operating conditions. An order of magnitude increase in particle concentration coincides with the valve timing changes. These concentration spikes range from 1 x10^8 to 3 x108 cm-3. This variability is attributed to the time response limitation of the DMS causing some samples to be taken during the first cycle after the valve timing change versus some being taken during subsequent cycles. After a spike in particle concentration due to a timing change, the value quickly returns to steady-state levels. The GMD remains at 15 nm throughout the test, suggesting that while the particle concentration increases due to timing changes, the mechanism for particle formation does not change.
BibTeX: @conference{CICS2013, author = {D. Bullock and A. Schramm and A. Momenimovahed and C. R. Koch and J. S. Olfert}, title = {Effects of Transient Valve Timing on Particulate Emission Concentration of a Homogeneous Charge Compression Ignition Engine}, booktitle = {Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting , Quebec City, QB}, year = {2013}, pages = {6}, url = {/ ckoch/open_access/CICS2013.pdf} }
Ebrahimi, K. and Koch, C.R.	HCCI Combustion Timing Control with Variable Valve Timing [Abstract] [BibTeX]	2013	2013 American Controls Conference (ACC), Washington, USA, pp. 3979 to 3984	conference	URL
Abstract: Homogeneous Charge Compression Ignition (HCCI) is a promising concept for combustion engines to reduce both emissions and fuel consumption. In HCCI engines, a homogeneous air-fuel mixture auto-ignites due to compression, which is unlike traditional spark ignition and diesel engines where ignition is started with either a spark or fuel injection. HCCI combustion control is a challenging issue because there is no direct initiator of combustion in HCCI engines. Variable Valve Timing (VVT) is one effective way to control the combustion timing in HCCI engines. VVT changes the amount of trapped residual gas and the effective compression ratio both of which have a strong effect on combustion timing. In order to control HCCI combustion, a physics based control oriented model is developed that includes the effect of trapped residual gas on combustion timing. The control oriented model is obtained by model order reduction of complex chemical kinetic reaction mechanisms. This method allows different fuels to be incorporated using a standard methodology and fills the gap between complex models with highly detailed chemical kinetics and simple black box models that have been used in model based control. The control oriented model is used to develop ignition timing PI control using simulation. The PI control modulates the trapped residual gas using variable valve timing as the actuator. The results indicate that the controller can track step changes in HCCI combustion timing.
BibTeX: @conference{Ebrahimi_acc2013, author = {K. Ebrahimi and C. R. Koch}, title = {HCCI Combustion Timing Control with Variable Valve Timing}, booktitle = {2013 American Controls Conference (ACC), Washington, USA}, year = {2013}, pages = {3979 to 3984}, url = {/ ckoch/open_access/Ebrahimi_acc2013.pdf} }
Ebrahimi, K., Schramm, A. and Koch, C.R.	A Control Oriented Model with Variable Valve Timing for HCCI Combustion Timing Control [Abstract] [BibTeX]	2013	SAE Paper 2013-01-0588, pp. 12	conference	URL
Abstract: Homogeneous Charge Compression Ignition (HCCI) is a promising concept for combustion engines to reduce both emissions and fuel consumption. HCCI combustion control is a challenging issue because there is no direct initiator of combustion. Variable Valve Timing (VVT) is being used in SI engines to improve engine efficiency. When VVT is used in conjunction with HCCI combustion it is an effective way to control the start of combustion. VVT changes the amount of trapped residual gas and the effective compression ratio for each cycle both of which have a strong effect on combustion timing in HCCI engines. To control HCCI combustion, a physics based control oriented model is developed that includes the effect of trapped residual gas on combustion timing. The control oriented model is obtained by taking a physics based model of the reaction kinetics and transient dynamics and systematically reducing the model using simplification of reaction mechanisms. This method allows different fuels to be incorporated using a standard methodology. The reduced order model consists of these five stages: intake, compression, combustion, expansion and exhaust. This model fills the gap between complex models with highly detailed chemical kinetics and simple black box dynamic models that have been used in model based control.
BibTeX: @conference{Ebrahimi2013_sae, author = {K. Ebrahimi and A. Schramm and C. R. Koch}, title = {A Control Oriented Model with Variable Valve Timing for HCCI Combustion Timing Control}, booktitle = {SAE Paper 2013-01-0588}, year = {2013}, pages = {12}, url = {/ ckoch/open_access/Ebrahimi2013_sae.pdf} }
Khaligh, S.P., Martinez, A., Fahimi, F. and Koch, C.R.	A HIL Testbed for Small Unmanned Helicopter's Initial Controller Gain Tuning [Abstract] [BibTeX]	2013	Int. Conf. on Unmanned Aircraft Systems, pp. 8	conference	URL
Abstract: A Hardware-In-The-Loop (HIL) testbed design for small unmanned helicopters is described. The testbed provides a safe and low-cost platform to implement control algorithms and tune the control gains in a controlled environment. Specifically, it allows for testing the robustness of the controller to external disturbances by emulating the hover condition. A 6-DOF nonlinear mathematical model of the helicopter has been validated in real flight tests. This model is implemented in real-time to estimates the states of the helicopter which are then used to determine the actual control signals on the testbed. A damping system with a negligible parasitic effect on the dynamics of the helicopter around hover is incorporated into the testbed design to minimize the structural stress on the fuselage in the case of controller failure or a subsystem malfunction. Three experiments including the longitudinal, lateral and heading control tests are performed. Experimental results show that the HIL testbed allows for designing a controller which is robust to the external disturbances, and achieves an accuracy of +-2cm in the position control along the longitudinal and lateral axes in hover, and that of +-1 deg around the yaw axis on the heading trajectory tracking.
BibTeX: @conference{ICUAS2013, author = {Sepehr P Khaligh and Alex Martinez and Farbod Fahimi and Charles Robert Koch}, title = {A HIL Testbed for Small Unmanned Helicopter's Initial Controller Gain Tuning}, booktitle = {Int. Conf. on Unmanned Aircraft Systems}, year = {2013}, pages = {8}, url = {/ ckoch/open_access/ICUAS2013.pdf} }
Seethaler, R., Mashkournia, M., Chladny, R.R., Zhao, J. and Koch, C.R.	Closed Loop Electromagnetic Valve Actuation Motion Control on a Single Cylinder Engine [Abstract] [BibTeX]	2013	SAE Paper 2013-01-0594, pp. 8	conference	URL
Abstract: In an effort to improve the efficiency of internal combustion engines, much focus has been put into variable valve actuation technologies in recent years. Electromagnetic solenoid valves can provide the cycle-by-cycle flexible valve timing needed for throttleless engine control or high efficiency combustion modes such as Homogeneous Charge Compression Ignition. One challenge with electromagnetic solenoid intake and exhaust valves is the robust control of the motion to achieve smooth landing under a variety of operating conditions. Promising algorithms have been demonstrated under test-bench conditions, but no work to date has demonstrated a robust electromagnetic valve-train on a functional engine that also satisfies soft landing and transition timing criteria. In this work, two previously developed valve motion controllers are experimentally tested on a single cylinder test engine. The controllers are compared for the opening transition of the exhaust valve with large variations in combustion pressure. A new control algorithm that combines favorable aspects of both methods is also presented. The new algorithm is shown to operate reliably under a wide range of operating conditions. An analysis indicates that the electrical energy consumed by the camless valve system is comparable to that of an equivalent conventional low friction cam-based valve train.
BibTeX: @conference{Setthaler2013sae, author = {R. Seethaler and M. Mashkournia and R. R. Chladny and J. Zhao and C. R. Koch}, title = {Closed Loop Electromagnetic Valve Actuation Motion Control on a Single Cylinder Engine}, booktitle = {SAE Paper 2013-01-0594}, year = {2013}, pages = {8}, url = {/ ckoch/open_access/Setthaler2013sae.pdf} }
Setayeshgar, A., Lipsett, M.G., Koch, C.R. and Nobes, D.S.	Measurement of particle dynamics in a coherent acoustic field [Abstract] [BibTeX]	2013	10th International Symposium on Particle Image Velocimitry, Delft Ntherlands, 2-4 July, pp. 2	conference	URL
Abstract: A variety of forces can be used to separate fine particles from water in industrial processes. A coherent standing acoustic field can apply a pressure difference across a small particle such that the particle is forced to nodes or anti-nodes in the field depending on particle/liquid properties. The motion of an individual particle which is a result of the balance of forces on the particle, including particle-to-particle interaction is of interest. This study develops a method to measure individual particle motion using a particle tracking velocimetry (PTV) approach. These results are aimed to investigate the effects of particle loading and are used to test the current theory which only addresses single particle motion in a standing acoustic field. This paper focuses on the application and validation of a PTV-based experiential measurement technique used to determine the forces applied on individual particles.
BibTeX: @conference{Setayesgar_2013, author = {A. Setayeshgar and M. G. Lipsett and C. R. Koch and D. S. Nobes}, title = {Measurement of particle dynamics in a coherent acoustic field}, booktitle = {10th International Symposium on Particle Image Velocimitry, Delft Ntherlands, 2-4 July}, year = {2013}, pages = {2}, url = {/ ckoch/open_access/Setayesgar_2013.pdf} }
Shahidi, S., Koch, C.R. and Bhattacharjee, S.	A Milli-Fluidic Device for Electrical Impedance Spectroscopy of Complex Liquids [Abstract] [BibTeX]	2013	(1)ASME Int Conf. San Diego, November 15-21,2013	conference	DOI URL
Abstract: Rapid characterization of complex liquids such as solutions, mixtures, dispersions, and emulsions is useful in a variety of industrial applications ranging from cosmetics, pharmaceuticals, to petroleum production. An electrical impedance spectroscopy (EIS) based technique for rapidly determining the characteristics of liquid-liquid mixtures is presented in this study. A milli-fluidic liquid film impedance measurement cell is developed employing 3D printing technology. The cell is tested using glycerol-water mixtures followed by castor oil in water emulsion samples. Frequency response analysis and equivalent circuit modeling are performed on each sample to quantify the emulsion properties in the form of equivalent capacitance and resistance. The developed technique provides a robust experimental platform for applying EIS to investigation and rapid estimation of different properties of oil-water emulsions.
BibTeX: @conference{Shahidi_asme_2013, author = {Shahidi, S. and Koch, Charles R. and Bhattacharjee, Subir}, title = {A Milli-Fluidic Device for Electrical Impedance Spectroscopy of Complex Liquids}, booktitle = {ASME Int Conf. San Diego, November 15-21,2013}, year = {2013}, number = {1}, url = {/ ckoch/open_access/Shahidi_asme_2013.pdf}, doi = {https://doi.org/10.1115/IMECE2013-65293} }
Bussiere, M., Nobes, D.S. and Koch, C.R.	A Combinatorial vortex detection and characterization algorithm for 2C2D PIV data [Abstract] [BibTeX]	2012	16th Int Symp on Applications of Laser Techniques to Fluid Mechanics, pp. 5	conference	URL
Abstract: In this study, the vortical wake conditions of water flowing past an oscillating symmetric airfoil are described with velocity vector fields obtained from particle image velocimetry (PIV) data. Vortices are identified and characterized with a combinatorial algorithm and were found to agree well with the Burgers vortex model. Velocity vector fields obtained experimentally are often accompanied by undesirable effects which are not present in numerical data. The algorithm overcomes these limitations in the data sets by making use of three separate detection methods to provide dependable vortex detection in a wide range of wake conditions.
BibTeX: @conference{Buss_2012, author = {M. Bussiere and D. S. Nobes and C. R. Koch}, title = {A Combinatorial vortex detection and characterization algorithm for 2C2D PIV data}, booktitle = {16th Int Symp on Applications of Laser Techniques to Fluid Mechanics}, year = {2012}, pages = {5}, note = {Lisbon 2012}, url = {/ ckoch/open_access/Buss_2012.pdf} }
Mashkournia, M. and Koch, C.R.	Cycle by Cycle Actuation of Intake Valve Closing in HCCI [Abstract] [BibTeX]	2012	Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting , Toronto, ON, pp. 6	conference	URL
Abstract: Homogeneous Charge Compression Ignition (HCCI) has the potential to improve automobile efficiency in part load operation. However, challenges of limited operating range as well as difficulty in mode switching from spark ignition to HCCI limit the practical use of HCCI technology. One system that shows promise for fast actuation and control of HCCI is fully variable valve timing. A fully variable electromagnetic valve timing system has been installed on a single cylinder research engine. Running in HCCI, the intake valve closing event is switched cycle by cycle between 180 degrees before top dead center (bTDC) to early valve closing during the intake stroke at 230 degrees bTDC in order to modify the effective compression ratio. A return map of the combustion timing for each cycle indicates deterministic ignition timing when cycling between these two operating points. Each operating point at steady state is then compared to the switched case by examining the return map, IMEP and maximum pressure rise rate.
BibTeX: @conference{CICS2012, author = {M. Mashkournia and C. R. Koch}, title = {Cycle by Cycle Actuation of Intake Valve Closing in HCCI}, booktitle = {Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting , Toronto, ON}, year = {2012}, pages = {6}, url = {/ ckoch/open_access/CICS2012.pdf} }
Nobes, D.S., Setayeshgar, A., Lipsett, M.G. and Koch, C.R.	Investigating the Particles Motion in Ultrasonic Acoustic Wave Field Using PIV/PTV [BibTeX]	2012	Vol. 1433International Congress on Ultrasonics, Poland, pp. 719-722	conference	DOI URL
BibTeX: @conference{Setayesgar_2012, author = {D. S. Nobes and A. Setayeshgar and M. G. Lipsett and C. R. Koch}, title = {Investigating the Particles Motion in Ultrasonic Acoustic Wave Field Using PIV/PTV}, booktitle = {International Congress on Ultrasonics, Poland}, publisher = {AIP}, year = {2012}, volume = {1433}, pages = {719-722}, url = {http://scitation.aip.org/content/aip/proceeding/aipcp/10.1063/1.3703283}, doi = {https://doi.org/10.1063/1.3703283} }
Bussiere, M., Nobes, D. and Koch, C.R.	The oscillatory behavior of a symmetric airfoil hinged at its aerodynamic centre in the wake of a circular cylinder [Abstract] [BibTeX]	2011	23rd Canadian Congress of Applied Mechanics, pp. 5	conference	URL
Abstract: A NACA 0012 airfoil free to rotate about its aerodynamic center is placed in the wake of a circular cylinder. The cylinder produces a periodic pattern of swirling vortices which cause pressure fluctuations across the airfoil and ultimately cause it to oscillate in a sustained periodic manner. This oscillatory behavior is characterized by the oscillation amplitude and frequency as well as the amplitude and frequency of pressure fluctuations measured on either side of the airfoil. How these characteristics vary with distance along the center of the cylinder wake is described.
BibTeX: @conference{Buss_2011, author = {M. Bussiere and D. Nobes and C. R. Koch}, title = {The oscillatory behavior of a symmetric airfoil hinged at its aerodynamic centre in the wake of a circular cylinder}, booktitle = {23rd Canadian Congress of Applied Mechanics}, year = {2011}, pages = {5}, note = {CANCAM 2011}, url = {/ ckoch/open_access/Buss_2011.pdf} }
Ebrahimi, K., Shahbakhti, M. and Koch, C.R.	Comparison of Butanol/n-Heptane as a Blended fuel in an HCCI engines [Abstract] [BibTeX]	2011	Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting, pp. 6	conference	URL
Abstract: Butanol and n-heptane fuel blends are compared to Primary Reference Fuel blends of iso-octane and n-heptane by measuring 98 steady-state HCCI combustion operating points. The volume percentage of the blended fuel with n-heptane and fuel equivalence ratio are varied while all other engine parameters are held constant. The experimental results show that HCCI operation is possible with Butanol blends up to 48.5% and with iso-octane blends up to 63%. Higher indicated thermal efficiencies when running the engine on blends of butanol are obtained compared to the PRF blends and the Butanol blends have a later start of combustion and a slower rate of heat release compared to the PRF blends. Operating points that have the same thermal efficiency but a lower volume percent of butanol compared to iso-octane have been found and this could be an advantage since a smaller amount of secondary fuel would be required.
BibTeX: @conference{CICS2011b, author = {K. Ebrahimi and M. Shahbakhti and C. R. Koch}, title = {Comparison of Butanol/n-Heptane as a Blended fuel in an HCCI engines}, booktitle = {Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting}, year = {2011}, pages = {6}, url = {/ ckoch/open_access/CICS2011b.pdf} }
Ghazimirsaied, A., Shahbakhti, M. and Koch, C.R.	Ignition timing criteria for partial burn operation in an HCCI engine [Abstract] [BibTeX]	2011	Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting, pp. 6	conference	URL
Abstract: Homogeneous Charge Compression Ignition (HCCI) has the potential to improve the efficiency of Spark Ignition (SI) or Compression Ignition (CI) engines particularly at part load near the partial burn/misfire limit. Two challenges of HCCI combustion are: maintaining constant ignition timing despite no direct mechanism to initiate combustion, and to expand the part load region of HCCI near the misfire limit. An accurate criteria of ignition timing is critical to accomplish this. The crank angle where the maximum pressure occurs (ThetaPmax) is proposed as a robust criteria for distinguishing between normal and misfire HCCI combustion modes. Particularly near the partial burn/misfire limit, this method is found to be more reliable than the existing methods of CA50 (Crank angle of 50 percent mass fraction burned). Using (ThetaPmax), normal and partial burn engine cycles can be determined cycle by cycle for fuels exhibiting a cool flame. The performance of this new criteria is then analyzed for different engine loads at both constant fueling and constant equivalence ratio at 329 HCCI experimental operating points, each with 100 cycles of cylinder pressure data. For operating points with high cyclic variation ThetaPmax is found to be more reliable than CA50. Thus ThetaPmax could be used in future feedback algorithms to help control to stabilize ignition timing in these regions extending the useful operating range of HCCI.
BibTeX: @conference{CICS2011a, author = {A. Ghazimirsaied and M. Shahbakhti and C. R. Koch}, title = {Ignition timing criteria for partial burn operation in an HCCI engine}, booktitle = {Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting}, year = {2011}, pages = {6}, url = {/ ckoch/open_access/CICS2011a.pdf} }
Mashkournia, M., Audet, A. and Koch, C.R.	Knock detection and control in an HCCI engine using DWT [Abstract] [BibTeX]	2011	Proceedings of the ASME 2011 Dynamic Systems and Control Conference, Morgantown, USA, pp. 391-399	conference	DOI URL
Abstract: The novel application of the Discrete Wavelet Transform (DWT) in a real time controller is used to detect and subsequently control knock in a Homogeneous Charge Compression Ignition (HCCI) engine. Classical Fourier techniques for knock detection are discussed and compared to Wavelet Transforms. The Discrete Wavelet Transform filter bank is chosen as the best method for knock detection due to its good time-resolution and low computational requirements. The DWT method is compared with the root mean squared value of the pressure trace as the benchmark method for determining knock and the two methods are linearly correlated. Using the DWT method for knock detection and modulating fuel octane, both a Proportional Integral (PI) and PI with Feed-forward control are implemented. Both of these methods reduce knock intensity for a step increase in engine load. The combination of Feed-forward with PI feedback is found to be slightly more effective than just PI feedback control.
BibTeX: @conference{ICEF2011, author = {Masoud Mashkournia and Adrian Audet and Charles Robert Koch}, title = {Knock detection and control in an HCCI engine using DWT}, booktitle = {Proceedings of the ASME 2011 Dynamic Systems and Control Conference, Morgantown, USA}, publisher = {ASME}, year = {2011}, pages = {391-399}, url = {/ ckoch/open_access/ICEF2011.pdf}, doi = {https://doi.org/10.1115/ICEF2011-60076} }
Nobes, D.S., Setayeshgar, A., Lipsett, M.G. and Koch, C.R.	Investigating the Particles Motion in Ultrasonic Acoustic Wave Field Using PIV/PTV [BibTeX]	2011	International Congress on Ultrasonics, Poland, pp. 4	conference	URL
BibTeX: @conference{Setayesgar_2011, author = {D. S. Nobes and A. Setayeshgar and M. G. Lipsett and C. R. Koch}, title = {Investigating the Particles Motion in Ultrasonic Acoustic Wave Field Using PIV/PTV}, booktitle = {International Congress on Ultrasonics, Poland}, publisher = {AIP}, year = {2011}, pages = {4}, url = {/ ckoch/open_access/Setayesgar_2011.pdf} }
Shahbakhti, M., Ghazimirsaied, A. and Koch, C.R.	Modeling Ranges Of Cyclic Variability For HCCI Ignition Timing Control [BibTeX]	2011	Proceedings of the ASME 2011 Dynamic Systems and Control Conference, pp. 8	conference	URL
BibTeX: @conference{DSCC_2011, author = {M. Shahbakhti and A. Ghazimirsaied and C. R. Koch}, title = {Modeling Ranges Of Cyclic Variability For HCCI Ignition Timing Control}, booktitle = {Proceedings of the ASME 2011 Dynamic Systems and Control Conference}, year = {2011}, pages = {8}, url = {/ ckoch/open_access/DSCC_2011.pdf} }
Boddez, J., Checkel., D. and Koch, C.R.	Mode Switiching Development for a Natural Gas SI- HCCI engine [BibTeX]	2010	Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting, pp. 6	conference	URL
BibTeX: @conference{CICS2010c, author = {J. Boddez and D. Checkel. and C. R. Koch}, title = {Mode Switiching Development for a Natural Gas SI- HCCI engine}, booktitle = {Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting}, year = {2010}, pages = {6}, url = {/ ckoch/open_access/CICS2010c.pdf} }
Ghazimirsaied, A., Shahbakhti, M. and Koch, C.R.	Recognizing partial burn operation in an HCCI engine [BibTeX]	2010	Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting, pp. 6	conference	URL
BibTeX: @conference{CICS2010a, author = {A. Ghazimirsaied and M. Shahbakhti and C. R. Koch}, title = {Recognizing partial burn operation in an HCCI engine}, booktitle = {Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting}, year = {2010}, pages = {6}, url = {/ ckoch/open_access/CICS2010a.pdf} }
Ghazimirsaied, A., Shahbakhti, M. and Koch, C.R.	COMPARISON OF CRANKANGLE BASED IGNITION TIMING METHODS ON AN HCCI ENGINE [BibTeX]	2010	Proceedings of the ASME Internal Combustion Engine Division 2010 Fall Conference	conference	URL
BibTeX: @conference{ICEF2010-35087, author = {Ahmad Ghazimirsaied and Mahdi Shahbakhti and Charles Robert Koch}, title = {COMPARISON OF CRANKANGLE BASED IGNITION TIMING METHODS ON AN HCCI ENGINE}, booktitle = {Proceedings of the ASME Internal Combustion Engine Division 2010 Fall Conference}, year = {2010}, url = {/ ckoch/open_access/ICEF2010-35087.pdf} }
Shahbakhti, M., Ghazimirsaied, A., Audet, A. and Koch, C.R.	Combustion characteristics of bio-Butanol/n-Heptane blend fuels in an HCCI engine [BibTeX]	2010	Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting, pp. 6	conference	URL
BibTeX: @conference{CICS2010b, author = {M. Shahbakhti and A. Ghazimirsaied and A. Audet and C. R. Koch}, title = {Combustion characteristics of bio-Butanol/n-Heptane blend fuels in an HCCI engine}, booktitle = {Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting}, year = {2010}, pages = {6}, url = {/ ckoch/open_access/CICS2010b.pdf} }
Audet, A. and Koch, C.R.	Actuator comparison for closed loop control of HCCI combustion timing [Abstract] [BibTeX]	2009	SAE Paper 2009-01-1135, pp. 8	conference	URL
Abstract: Homogeneous Charge Compression Ignition (HCCI) is an emerging combustion technology due to its increased efficiency and decreased nox emissions. One of the most challenging aspects of HCCI is the regulation of the combustion timing. Unlike conventional combustion modes there is no direct control over the start of combustion. Autoignition timing is a function of the temperature, pressure and composition of the mixture, so to adjust the combustion timing of HCCI changes have to be made to these. Both variable valve timing and variable fuel octane number are effective inputs to achieve cycle-to-cycle combustion control of HCCI combustion timing. The application of these control methods are investigated in this paper. A one-cylinder Ricardo engine is fitted with a 4-valve spark ignition cylinder head equipped with camshaft phasers. These phasers independently adjust both the intake and exhaust camshaft phasing. By modifying the intake valve timing the effective compression ratio is changed, which affects the temperature-pressure condition of the mixture. Variable fuel octane is realized using two independent fuel injector systems, one equipped with iso-Octane and the other with n-Heptane. The CA50 (crank angle of 50% mass fraction burned) is regulated using feedback control and two separate actuators for combustion timing are implemented; intake camshaft phasing and variable fuel octane. These actuators are compared according to their range of operation and ability to reject system disturbances. The different combustion controllers are subjected to disturbances of both engine speed and engine load (changes in injected fuel energy). The results show the benefits and limitations of each actuator.
BibTeX: @conference{Audet2009sae, author = {A. Audet and C. R. Koch}, title = {Actuator comparison for closed loop control of HCCI combustion timing}, booktitle = {SAE Paper 2009-01-1135}, year = {2009}, pages = {8}, url = {/ ckoch/open_access/Audet2009sae.pdf} }
Ghazimirsaied, A., Shahbakhti, M. and Koch, C.R.	Partial-burn crankangle limit criteria comparison on an experimental HCCI engine [Abstract] [BibTeX]	2009	Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting, pp. 6	conference
Abstract: Misfire and partial-burn criteria are defined using crank angle based engine parameters and investigated on an experimental Homogeneous charge compression ignition (HCCI) single-cylinder engine at 59 operating conditions. The best criteria to distinguish between normal, partial burn and misfire operating conditions for this engine are: the standard deviation of CA10 (Crank angle at which 10 percent of fuel mass has burned) and burn duration. The partial burn limit for five different blends of isooctane and n-heptane fuels is presented. Increasing the manifold pressure at each specific fuel octane number results in a lower equivalence ratio partial burn limit for the engine operating points tested
BibTeX: @conference{CICS2009b, author = {A. Ghazimirsaied and M. Shahbakhti and C. R. Koch}, title = {Partial-burn crankangle limit criteria comparison on an experimental HCCI engine}, booktitle = {Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting}, year = {2009}, pages = {6} }
Ghazimirsaiied, A., Shahbakhti, M. and Koch, C.R.	Nonlinear Dynamics in Cyclic Variations of Combustion Phasing in an HCCI Engine [BibTeX]	2009	ASME 2009 Int. Comb. Engine Conf., Milwwaukee, USA, pp. 8	conference	URL
BibTeX: @conference{Ghazi_ices09, author = {A. Ghazimirsaiied and M. Shahbakhti and C. R. Koch}, title = {Nonlinear Dynamics in Cyclic Variations of Combustion Phasing in an HCCI Engine}, booktitle = {ASME 2009 Int. Comb. Engine Conf., Milwwaukee, USA}, year = {2009}, pages = {8}, url = {/ ckoch/open_access/Ghazi_ices09.pdf} }
Shahbakhti, M., Ghazimirsaied, A. and Koch, C.R.	The Effect of Operating Conditions on HCCI Exhaust Gas Temperature [Abstract] [BibTeX]	2009	Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting, pp. 6	conference
Abstract: To successfully use an exhaust aftertreatment system to overcome high HC and CO emissions in Homogeneous Charge Compression Ignition (HCCI) engines requires high exhaust gas temperatures for oxidation catalysts. Low exhaust gas temperature in certain HCCI conditions is a limiting factor to obtain a large desirable operating range in HCCI engines. This paper investigates the influence of combustion chamber charge conditions on the exhaust gas temperature in a single cylinder experimental engine at over 160 operating points. For the conditions tested, more than half of the collected data exhibits an exhaust gas temperature below 300^circC which is below the light-off temperature of typical catalytic converters in the market. Location of ignition timing is found as a main factor to influence HCCI exhaust gas temperature. HCCI combustion occurring immediately after TDC indicates a lower exhaust temperature compared to the HCCI combustion that occurs late after TDC. HCCI ignition timing also influences HC and CO and NOx emissions and advancing ignition towards TDC causes lower HC and CO but higher NOx emissions. In addition, results at a constant load condition indicate longer burn duration and higher fueling rate in Spark Ignition (SI) mode lead to have higher exhaust gas temperature in SI mode comparing to that of HCCI mode.
BibTeX: @conference{CICS2009a, author = {M. Shahbakhti and A. Ghazimirsaied and C. R. Koch}, title = {The Effect of Operating Conditions on HCCI Exhaust Gas Temperature}, booktitle = {Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting}, year = {2009}, pages = {6} }
Shahbakhti, M. and Koch, C.R.	Predicting the Distribution of Combustion Timing Ensemble in an HCCI Engine [BibTeX]	2009	ICES2009 Paper, pp. 12	conference
BibTeX: @conference{Shahbakhti_ices09, author = {M. Shahbakhti and C. R. Koch}, title = {Predicting the Distribution of Combustion Timing Ensemble in an HCCI Engine}, booktitle = {ICES2009 Paper}, year = {2009}, pages = {12} }
Shahbakhti, M. and Koch, C.R.	Dynamic Modeling of HCCI Combustion Timing in Transient Fueling Operation [Abstract] [BibTeX]	2009	SAE Paper 2009-01-1136, pp. 16	conference
Abstract: A physics-based control-oriented model is developed to dynamically predict cycle-to-cycle combustion timing in transient fueling conditions for Homogeneous Charge Compression Ignition (HCCI) engines. The model simulates the engine cycle from the intake stroke to the exhaust stroke and includes the thermal coupling dynamics caused by the residual gases from one cycle to the next cycle. A residual gas model, a modified knock integral model, a fuel burn rate model, and thermodynamic models for the gas state in combustion and exhaust strokes are incorporated to simulate the engine cycle. The gas exchange process, generated work and completeness of combustion are predicted using semi-empirical correlations. The resulting model is parameterized for the combustion of Primary Reference Fuel (PRF) blends using 5703 simulations from a detailed thermo-kinetic model. Semi-empirical correlations in the model are parameterized using the experimental data obtained from a single-cylinder engine. The dynamics of fuel transport from intake port into the cylinder is described using the wall wetting fuel dynamic model. Step Air Fuel Ratio (AFR) excursions are used to excite the HCCI engine to determine
BibTeX: @conference{Shahbakhti2009sae, author = {M. Shahbakhti and C. R. Koch}, title = {Dynamic Modeling of HCCI Combustion Timing in Transient Fueling Operation}, booktitle = {SAE Paper 2009-01-1136}, year = {2009}, pages = {16} }
Audet, A. and Koch, C.R.	Experimental HCCI Cyclic Variations using Camshaft Phasing [Abstract] [BibTeX]	2008	Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting, pp. 6	conference	URL
Abstract: The effect of valve timing on cyclic variation of Homogeneous Charge Compression Ignition (HCCI) combustion is experimentally investigated. The understanding of the effect engine parameters have on the cyclic variations of HCCI is needed to control the combustion phasing of HCCI. Cyclic variation control is necessary since the load range of HCCI is partially limited by high cyclic variations seen at the misfire limit. A one-cylinder Ricardo engine with a Mercedes 4-valve camshaft phasing cylinder head is operated at a constant speed, intake temperature and intake pressure. Using camshaft phasers the timing of both the intake and exhaust valves are independently changed at different levels of engine load and fuel octane number. Phasing the intake valves primarily effects the effective compression ratio of the engine, and it is observed that decreasing the effective compression ratio increases the cyclic variation of the timing of HCCI but has little effect on the cyclic variation of Indicated Mean Effective Pressure (IMEP). Phasing of the exhaust valves is used to obtain negative valve overlap which results in trapped residuals. Increases in these trapped residuals is seen to effect both cyclic variation of combustion phasing as well as IMEP mainly through charge temperature.
BibTeX: @conference{CICS2008a, author = {A. Audet and C. R. Koch}, title = {Experimental HCCI Cyclic Variations using Camshaft Phasing}, booktitle = {Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting}, year = {2008}, pages = {6}, url = {/ ckoch/open_access/CICS2008a.pdf} }
Ghazimirsaied, A., Shahbakhti, M., Audet, A. and Koch, C.R.	Characterizing Cyclic Variations in an HCCI Engine using Chaotic and Statistical Methods [Abstract] [BibTeX]	2008	Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting, pp. 6	conference
Abstract: This paper investigates the cyclic variation of ignition timing in an Homogeneous Charge Compression Ignition (HCCI) engine using a range of experimental data collected from a single-cylinder Ricardo engine. Under certain operating conditions, HCCI engines can exhibit large cyclic variations in ignition timing. Cyclic variability ranging from stochastic to deterministic patterns can be observed. This work applies two methods to study patterns of CA50 (Crank angle of 50% fuel burnt) cyclic variation in an HCCI engine. Nine points ranging from the misfire to knock limit within the HCCI mode are experimentally measured by varying the intake manifold temperature. The return map techniques used in nonlinear dynamics and chaos theory are applied to observe possible deterministic structures inherent in these points. Probability distribution for cyclic combustion timing is the second approach examined. Experimental data of 338 different points over a wide range of operating conditions are examined to find out the conditions where a normal distribution for CA50 is observed. Three common statistical testing methods are used to verify the hypothesis of having a normal distribution for each data point.
BibTeX: @conference{CICS2008b, author = {A. Ghazimirsaied and M. Shahbakhti and A. Audet and C. R. Koch}, title = {Characterizing Cyclic Variations in an HCCI Engine using Chaotic and Statistical Methods}, booktitle = {Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting}, year = {2008}, pages = {6} }
Tsai, C.M., Koch, C.R. and Saif, M.	Cycle Adaptive Feedforward Approach Control of an Electromagnetic Valve Actuator [Abstract] [BibTeX]	2008	47th IEEE Conference on Decision and Control (CDC), Cancun, Mexico,, pp. 5698 - 5703	conference	URL
Abstract: An electromagnetic valvetrain on an internal combustion engine can improve the engine thermal efficiency but requires control to achieve soft landing and to avoid excessive wear and noise. Since the valves open and close repetitively, cycle adaptive control can be utilized. A cyclic adaptive feedforward approach controller for automotive electromagnetic valve is presented. This method uses a Nelder-Mead direct search algorithm with the goal of setting constant initial conditions for the landing control. Simulation and testbench results are presented and they show that the approach control works well for disturbances that are slow compared to the valve travel time.
BibTeX: @conference{Tsai_cdc2008, author = {C. M. Tsai and C. R. Koch and M. Saif}, title = {Cycle Adaptive Feedforward Approach Control of an Electromagnetic Valve Actuator}, booktitle = {47th IEEE Conference on Decision and Control (CDC), Cancun, Mexico,}, year = {2008}, pages = {5698 - 5703}, url = {/ ckoch/open_access/Tsai_cdc2008.pdf} }
M.Shahbakhti, Lupul, R., Audet, A. and Koch, C.R.	Experimental Study of HCCI Cyclic Variations for Low-Octane PRF Fuel Blends [Abstract] [BibTeX]	2007	Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting, pp. 6	conference	URL
Abstract: The operating range of Homogeneous Charge Compression Ignition (HCCI) engines is limited by the knock boundary on one side and by high cyclic variations (misfire) on the other side. A challenging problem for HCCI engines is achieving cycle-by-cycle ignition control due to these variations. To control combustion in HCCI engines, it is essential to understand how parameters affect the cyclic variations of HCCI combustion. This paper investigates cyclic variability of HCCI combustion using experimental data collected at 360 operating points from a single cylinder Ricardo engine. The engine is fueled with four different blends of Primary Reference Fuels PRFs (iso-octane and nheptane) at octane values of 0, 10, 20 and 40 over a wide range of equivalence ratios, intake temperatures, intake pressures, Exhaust Gas Recirculation (EGR) rates, and engine speeds. The experimental results show there are three main distinct patterns of cyclic variations for combustion peak pressure (Pmax), Indicated Mean Effective Pressure (IMEP) and ignition timing. These patterns include normal cyclic variations, periodic cyclic variations and cyclic variations with weak/misfired ignitions. The results also show cyclic variation of HCCI combustion is highly dependant on the location of the start of combustion and there is less cyclic variation in the first stage of HCCI combustion compared to that of the second stage for the PRF blends studied.
BibTeX: @conference{CICS2007b, author = {M.Shahbakhti and R. Lupul and A. Audet and C. R. Koch}, title = {Experimental Study of HCCI Cyclic Variations for Low-Octane PRF Fuel Blends}, booktitle = {Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting}, year = {2007}, pages = {6}, url = {/ ckoch/open_access/CICS2007b.pdf} }
Shahbakhti, M. and Koch, C.R.	Thermo-Kinetic Combustion Modeling Of An HCCI Engine To Analyze Ignition Timing For Control Applications [Abstract] [BibTeX]	2007	Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting, pp. 6	conference	URL
Abstract: Ignition timing in Homogeneous Charge Compression Ignition (HCCI) engines is dominated by thermo-kinetic reactions that are dependant on the charge properties. A single zone thermodynamic model, coupled to a kinetic mechanism, is developed to predict the ignition timing of Primary Reference Fuels (PRFs) in an HCCI engine. The model, consisting of 120 chemical reactions and 58 species, is validated against the experimental data from a single cylinder engine for various operating conditions. The model is able to predict the effects of different charge parameters on the HCCI ignition timing. This model is used to perform a sensitivity analysis of HCCI ignition timing to the variations of engine charge properties in order to examine the relative importance of different charge properties for control applications. The sensitivity analysis is done for these main charge variables: initial temperature, initial pressure, Exhaust Gas Recirculation (EGR) rate, equivalence ratio, and octane number. The simulation results show that the sensitivity of HCCI ignition timing is dependant on the crank angle position of the Start of Combustion (SOC). The highest sensitivity of HCCI ignition timing is always seen to the variation of the charge temperature.
BibTeX: @conference{CICS2007a, author = {M. Shahbakhti and C. R. Koch}, title = {Thermo-Kinetic Combustion Modeling Of An HCCI Engine To Analyze Ignition Timing For Control Applications}, booktitle = {Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting}, year = {2007}, pages = {6}, url = {/ ckoch/open_access/CICS2007a.pdf} }
Shahbakhti, M. and Koch, C.R.	Control Oriented Modeling of Combustion Phasing for an HCCI Engine [Abstract] [BibTeX]	2007	2007 American Controls Conference (ACC), New York, USA, pp. 3979 to 3984	conference	URL
Abstract: A promising method for enhancing emission and fuel consumption of internal combustion engines is the Homogeneous Charge, Compression Ignition (HCCI) engine. Control of ignition timing is the major challenge before the potential benefits of HCCI combustion can be fully realized in production applications. The goal of this paper is to develop a real time model for predicting combustion phasing for HCCI control applications. The standard Knock-Integral model is developed and linked with semi-empirical correlations for gas exchange process and fuel heat release to predict HCCI combustion phasing (CA50, crank angle where 50% of the fuel is burnt). The MKIM model is parameterized using a thermokinetic simulation model. Experimental data from a single cylinder engine at several HCCI operation conditions and three fuel blends is used to validate the model.
BibTeX: @conference{Shahbakhti_acc2007, author = {M. Shahbakhti and C. R. Koch}, title = {Control Oriented Modeling of Combustion Phasing for an HCCI Engine}, booktitle = {2007 American Controls Conference (ACC), New York, USA}, year = {2007}, pages = {3979 to 3984}, url = {/ ckoch/open_access/Shahbakhti_acc2007.pdf} }
Shahbakhti, M., Lupul, R. and Koch, C.R.	Sensitivity Analysis And Modeling Of HCCI Auto-Ignition Timing [Abstract] [BibTeX]	2007	Proceedings of Fifth IFAC Symposium on Advances in Automotive Control, Monterey Coast, California, USA, pp. 8	conference
Abstract: To control auto-ignition timing in a Homogeneous Charge Compression Ignition (HCCI) engine, it is essential to be able to predict the auto-ignition timing. Since charge properties influence the auto-ignition timing, a control-oriented model is further developed to predict the HCCI auto-ignition timing and the sensitivity to the charge properties is examined. The simulation results show that in the studied range the Start of Combustion (SOC) is the most sensitive to the variation of charge temperature and the least sensitive to the variation of Exhaust Gas Recirculation (EGR) rate and the sensitivity to charge temperature increases with decreasing EGR rate.
BibTeX: @conference{ifac2007, author = {M. Shahbakhti and R. Lupul and C. R. Koch}, title = {Sensitivity Analysis And Modeling Of HCCI Auto-Ignition Timing}, booktitle = {Proceedings of Fifth IFAC Symposium on Advances in Automotive Control, Monterey Coast, California, USA}, year = {2007}, pages = {8} }
Shahbakhti, M., Lupul, R. and Koch, C.R.	Predicting HCCI Auto-Ignition Timing by Extending a Modified Knock-Integral Method [Abstract] [BibTeX]	2007	SAE Paper 2007-01-0222	conference	URL
Abstract: One major challenge in Homogeneous Charge Compression Ignition (HCCI) combustion is the difficulty in controlling the timing of auto-ignition which is dependant on mixture conditions. Understanding the effect of modifying the properties of the engine charge on the start of combustion is essential to be able to predict and control the auto-ignition timing. The purpose of this work is to develop a realtime model for predicting HCCI auto-ignition timing. The standard Livengood and Wu Knock-Integral Method (KIM) is modified to work with values that are easier to measure compared with the instantaneous in-cylinder parameters required in the original KIM. This modified Knock-Integral Method (MKIM) is developed and is then parameterized using HCCI Thermokinetic Kinetic Model (TKM) simulations for a single cylinder engine. Estimating the MKIM parameters is done using an off-line optimization technique. Once the parameters have been identified, the MKIM needs only the rate of Exhaust Gas Recirculated (EGR), equivalence ratio, intake manifold temperature and intake manifold pressure to predict auto-ignition timing. The MKIM is validated with the experimental data from the single cylinder engine in HCCI operation by varying equivalence ratio, EGR level, engine speed, and intake temperature for three different blends of Primary Reference Fuels (PRF) at octane values of 0, 10 and 20.
BibTeX: @conference{Shahbakhti2007, author = {M. Shahbakhti and R. Lupul and C. R. Koch}, title = {Predicting HCCI Auto-Ignition Timing by Extending a Modified Knock-Integral Method}, booktitle = {SAE Paper 2007-01-0222}, year = {2007}, url = {/ ckoch/open_access/Shahbakhti2007.pdf} }
Shahbakhti, M., Lupul, R. and Koch, C.R.	Cyclic Variations of Ignition Timing in an HCCI Engine [Abstract] [BibTeX]	2007	Proceedings of JRCICE2007 2007 ASME/IEEE Joint Rail Conference & Internal Combustion Engine Spring Technical Conf.,Pueblo, Colorado, USA, pp. 6	conference
Abstract: Understanding the effect of modifying the properties of the engine charge on the cyclic variations of ignition timing is one essential aspect of being able to predict and control the ignition timing in Homogeneous Charge Compression Ignition (HCCI) engines. This paper investigates cyclic variability of HCCI ignition timing using the experimental data from two different engines at over 300 operating points for five different blends of iso-octane and n-heptane. Experimental results indicate that the cyclic variations of HCCI auto-ignition timing decrease with an increase in the intake manifold temperature and mixture richness, but it increases with an increase in the EGR rate.
BibTeX: @conference{jrcice2007_40032, author = {M. Shahbakhti and R. Lupul and C. R. Koch}, title = {Cyclic Variations of Ignition Timing in an HCCI Engine}, booktitle = {Proceedings of JRCICE2007 2007 ASME/IEEE Joint Rail Conference & Internal Combustion Engine Spring Technical Conf.,Pueblo, Colorado, USA}, year = {2007}, pages = {6} }
Chladny, R.R. and Koch, C.R.	Magnetic Flux-Based Position Sensor for Control of an Electromechanical VVT Actuator [Abstract] [BibTeX]	2006	2006 American Controls Conference (ACC), Minneapolois, MN, USA. Received Best Paper in Session award., pp. 3979 to 3984	conference	URL
Abstract: A promising method for enhancing automotive internal combustion engine efficiency uses solenoid actuators to directly control gas exchange valves. Mitigation of valve seating velocities is challenging due to phenomena such as magnetic saturation and pressure disturbances. Production implementation of an electromagnetic valvetrain will require the development of cost effective yet accurate sensors for robust feedback control. A method of magnetic flux-based armature position measurement is presented. Also provided is an overview of the modeling, control design, and experimental and simulated results acquired to date using such a sensor configuration.
BibTeX: @conference{Chladny2006a, author = {R. R. Chladny and C. R. Koch}, title = {Magnetic Flux-Based Position Sensor for Control of an Electromechanical VVT Actuator}, booktitle = {2006 American Controls Conference (ACC), Minneapolois, MN, USA. Received Best Paper in Session award.}, year = {2006}, pages = {3979 to 3984}, url = {/ ckoch/open_access/Chladny2006a.pdf} }
Chladny, R.R. and Koch, C.R.	Flatness-Based Tracking of an Electromechanical VVT actuator with magnetic flux sensor [Abstract] [BibTeX]	2006	IEEE International Conference on Control Applications, Munich, Germany, pp. 1663 to 1668	conference	URL
Abstract: A flatness-based end controller of an automotive solenoid valve has been demonstrated in both simulation and on an actuator test-bench. The simulation model provides an accurate representation of the real system and allows for the development of control strategies. The simulation results are contrasted with those of an actuator test-bench equipped with 42 volt automotive solenoid valves and a pressure chamber to simulate valve opening with exhaust gas pressures. A flux-based sensor which is suitable for real engine operation is used for position estimation in the soft-landing control.
BibTeX: @conference{Chladny2006, author = {R. R. Chladny and C. R. Koch}, title = {Flatness-Based Tracking of an Electromechanical VVT actuator with magnetic flux sensor}, booktitle = {IEEE International Conference on Control Applications, Munich, Germany}, year = {2006}, pages = {1663 to 1668}, url = {/ ckoch/open_access/Chladny2006.pdf} }
Swan, K., Shahbakhti, M. and Koch, C.R.	Predicting Start of Combustion Using a Modified Knock Integral Method for an HCCI Engine [BibTeX]	2006	SAE Paper 2006-01-1086, pp. 10	conference	URL
BibTeX: @conference{Swan2006, author = {K. Swan and M. Shahbakhti and C. R. Koch}, title = {Predicting Start of Combustion Using a Modified Knock Integral Method for an HCCI Engine}, booktitle = {SAE Paper 2006-01-1086}, year = {2006}, pages = {10}, url = {/ ckoch/open_access/Swan2006.pdf} }
Tzanetakis, T., Thomson, M. and Koch, C.R.	Multi-Zone Modeling of a Primary Reference Fuelled HCCI Engine, [BibTeX]	2006	Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting, pp. 6	conference
BibTeX: @conference{Tzanetakis2006, author = {T. Tzanetakis and M. Thomson and C. R. Koch}, title = {Multi-Zone Modeling of a Primary Reference Fuelled HCCI Engine,}, booktitle = {Combustion Institute/Canadian Section (CI/CS) Spring Technical Meeting}, year = {2006}, pages = {6} }
Supeene, G., Koch, C.R. and Bhattacharjee, S.	Numerically Modeled Dynamic Response of Perfect and Leaky Dielectrical Droplets in an Electric Field [BibTeX]	2005	Proceedings of ICMENS 2005, pp. p99	conference
BibTeX: @conference{Supeene, author = {G. Supeene and C. R. Koch and S. Bhattacharjee}, title = {Numerically Modeled Dynamic Response of Perfect and Leaky Dielectrical Droplets in an Electric Field}, booktitle = {Proceedings of ICMENS 2005}, year = {2005}, pages = {p99} }
Koch, C.R., Lynch, A.F. and Chung, S.K.	Flatness-based automotive solenoid valve control [Abstract] [BibTeX]	2004	Proc. of Nonlinear Control Systems Stuttgart Germany, Elsevier Science, pp. 1091 -1096	conference
Abstract: This paper considers the control of solenoid valve actuators used for gas exchange in internal combustion engines. Solenoid valves offer performance benefits over traditional camshaft-based valve timing. Maintaining the impact velocity of the armature and valve is an important performance specification. Flatness-based control provides linear stable tracking error dynamics assuming voltage control. In order to incorporate voltage constraints, magnetic saturation, and to ensure an appropriate position-velocity-acceleration profile, the flat output is parameterized with a spline basis. Non-linear programming is used to obtain optimal spline coefficients for the flat output trajectory.
BibTeX: @conference{Koch2004, author = {C. R. Koch and A. F. Lynch and S. K. Chung}, title = {Flatness-based automotive solenoid valve control}, booktitle = {Proc. of Nonlinear Control Systems Stuttgart Germany, Elsevier Science}, year = {2004}, pages = {1091 -1096} }
Arthur, D.M., Checkel, M.D. and Koch, C.R.	Developing Hydrogen Infrastructure through near-term intermediate technology [BibTeX]	2003	Hydrogen and Fuel Cells 2003 conference and trade show, Vancouver	conference
BibTeX: @conference{Arthur2003, author = {D. M. Arthur and M. D. Checkel and C. R. Koch}, title = {Developing Hydrogen Infrastructure through near-term intermediate technology}, booktitle = {Hydrogen and Fuel Cells 2003 conference and trade show, Vancouver}, year = {2003} }
Atkins, M.A. and Koch, C.R.	A Well-to-Wheel Comparison of Several Powertrain Technologies [BibTeX]	2003	SAE Paper 2003-01-0081	conference	URL
BibTeX: @conference{Atkins, author = {M. A. Atkins and C. R. Koch}, title = {A Well-to-Wheel Comparison of Several Powertrain Technologies}, booktitle = {SAE Paper 2003-01-0081}, year = {2003}, url = {/ ckoch/open_access/Atkins.pdf} }
Lynch, A.F. and Koch, C.R.	Control of Precision Electromagnetic Actuators: Active Magnetic Bearings and Solenoid Valve Actuators [BibTeX]	2003	Proceedings of the Second CSME Biennial Symposium on Mechatronics, Calgary AB	conference
BibTeX: @conference{Lynch2003, author = {A. F. Lynch and C. R. Koch}, title = {Control of Precision Electromagnetic Actuators: Active Magnetic Bearings and Solenoid Valve Actuators}, booktitle = {Proceedings of the Second CSME Biennial Symposium on Mechatronics, Calgary AB}, year = {2003} }
Koch, C.R., Lynch, A.F. and Chladny, R.R.	Modeling and control of solenoid valves for internal combustion engines [Abstract] [BibTeX]	2002	Proc. of the 2nd IFAC Conference on Mechatronic Systems, Berkeley, CA.	conference
Abstract: This paper considers the modeling and control of solenoid valve actuators used for gas exchange in internal combustion engines. Solenoid valves are an emerging technology which offers performance benefits over traditional camshaft based valve timing. Maintaining the impact velocity of the armature and valve is a primary performance requirement in order to minimize acoustic noise and mechanical wear. To control this velocity, the finite element method (FEM) is used to generate static force and flux data which is validated experimentally. A flatness-based control provides linear tracking error dynamics assuming current control. A reduced-order nonlinear velocity/disturbance observer ensures linear estimate error dynamics for constant force disturbances. The estimated state feedback is simulated using the FEM model flux and force data and acceptable impact velocity and acceleration are achieved in face of model uncertainty disturbance.
BibTeX: @conference{Koch2002, author = {C. R. Koch and A. F. Lynch and R. R. Chladny}, title = {Modeling and control of solenoid valves for internal combustion engines}, booktitle = {Proc. of the 2nd IFAC Conference on Mechatronic Systems, Berkeley, CA.}, year = {2002} }