The Experts below are selected from a list of 18261 Experts worldwide ranked by ideXlab platform
Guoming G. Zhu - One of the best experts on this subject based on the ideXlab platform.
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SI and HCCI Combustion Mode Transition Control of an HCCI Capable SI Engine
IEEE Transactions on Control Systems Technology, 2013Co-Authors: Xiaojian Yang, Guoming G. ZhuAbstract:The Combustion Mode transition between spark ignition (SI) and homogeneous charge compression ignition (HCCI) Combustion of an internal Combustion (IC) engine is challenging due to the distinct engine operating parameters over the two Combustion Modes and the cycle-to-cycle residue gas dynamics during the Mode transition. The control problem becomes even more complicated for a multicylinder engine without camless variable valve actuators. This paper studies the Combustion Mode transition problem of a multicylinder IC engine equipped with dual-stage valve lift and electrical variable valve timing (VVT) systems. Hardware-in-the-loop (HIL) simulations were used as a tool to develop and validate the proposed control strategies. Based on the HIL simulation results, this paper shows that smooth Combustion Mode transition can be realized in a few engine cycles. During the Mode transition, a Model-based linear quadratic tracking strategy was used to track the desired engine manifold pressure through the engine throttle control to maintain the engine AFR in a desired range; the fuel quantity of individual cylinder was controlled via the iterative learning; and engine spark was maintained for the SI-HCCI (or spark assistant) hybrid Combustions during the Combustion Mode transition. The HIL simulations demonstrated the effectiveness of the developed control strategies under both steady state and transient engine operating conditions. As a result, it is feasible to have a smooth Combustion Mode transition for an HCCI capable SI engine equipped with dual-stage valve lift and electrical VVT systems.
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ACC - Air-to-fuel ratio regulation during SI to HCCI Combustion Mode transition using the LQ tracking control
2012 American Control Conference (ACC), 2012Co-Authors: Xiaojian Yang, Guoming G. Zhu, Xuefei ChenAbstract:The Combustion Mode transition between spark ignition (SI) and homogeneous charge compression ignition (HCCI) Combustions of an internal Combustion (IC) engine is challenging due to the distinct engine operating parameters over the two Combustion Modes and the cycle-to-cycle residue gas dynamics during the Mode transition. The control problem becomes even more complicated for a multi-cylinder engine without camless valve actuation. This paper studies the Combustion Mode transition problem of a multi-cylinder IC engine with dual-stage valve lift and electrical variable valve timing (VVT) systems. Hardware-in-the-loop (HIL) simulations were used to develop and validate the proposed control strategies. The HIL simulation results show that smooth Combustion Mode transition can be realized utilizing the hybrid Combustion Mode in a few engine cycles and in-cylinder air-to-fuel ratio during the Mode transition needs to be regulated to the desired level. This paper presents a Model based linear quadratic tracking strategy to track the desired air-to-fuel ratio by controlling the engine throttle. The HIL simulations demonstrated the effectiveness of the developed control strategies. As a result, it is feasible to have a smooth Combustion Mode transition with dual-stage valve lift and electrical VVT systems.
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SI and HCCI Combustion Mode Transition Control of a Multi-Cylinder HCCI Capable SI Engine via Iterative Learning
ASME 2011 Dynamic Systems and Control Conference and Bath ASME Symposium on Fluid Power and Motion Control Volume 2, 2011Co-Authors: Xiaojian Yang, Guoming G. ZhuAbstract:The Combustion Mode transition between spark ignition (SI) and homogeneously charged compression ignition (HCCI) Combustions of an internal Combustion (IC) engine is challenging due to the distinct engine operational parameters over these two Combustion Modes and the cycle-to-cycle residue gas dynamics of the HCCI Combustion. The control problem becomes even more complicated when multi-cylinder operation is involved. This paper studies the Combustion Mode transition problem of a multi-cylinder IC engine with dual-stage valve lifts and electrical variable valve timing systems. A control oriented engine Model was used to develop a multistep Mode transition control strategy via iterative learning for Combustion Mode transition between SI to HCCI with minimal engine torque fluctuations. The hardware-in-the-loop (HIL) simulations demonstrated the effectiveness of the developed control strategy for the Combustion Mode transition under both constant load and transient engine operational conditions.
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ACC - Modeling and control of an electric variable valve timing system for SI and HCCI Combustion Mode transition
Proceedings of the 2011 American Control Conference, 2011Co-Authors: Zhen Ren, Guoming G. ZhuAbstract:This paper Models an electric variable valve timing (VVT) system and develops the corresponding controller for the electric VVT system. The studied electric VVT uses a planetary gear system for engine cam timing control; and a cyclic torque disturbance is applied to the cam shaft. The main motivation of utilizing the electric VVT system is for the Mode transition control between the spark ignited (SI) and homogeneous charge compression ignition (HCCI) Combustions due to its fast response time. During the Combustion Mode transition between SI and HCCI operations, it is required for the engine cam timing to follow a desired trajectory to make the smooth Combustion Mode transition possible. This is mainly due to the fact that the engine valve timings effect the engine recompression operation that is directly associated with the start of HCCI Combustion. A control oriented electric VVT Model was developed and closed-loop control strategies were developed to maintain the cam phase at a desired level, as well as to follow a desired trajectory during the Combustion Mode transition. Simulation results are included.
Fei Qin - One of the best experts on this subject based on the ideXlab platform.
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Local supersonic and subsonic Combustion Mode transition in a supersonic jet flame
Proceedings of the Combustion Institute, 2019Co-Authors: Donggang Cao, Fei Qin, Dan MichaelsAbstract:Abstract An experimental and computational study has been carried out for a supersonic jet flame by using OH chemiluminescence imaging, shadowgraph visualization, temperature measurement by TDLAS, pressure measurement by transducers, and large eddy simulation (LES) together with a skeletal reaction mechanism involving 13 species and 41 steps. Agreements have been found between experimental data and LES results, which are subsequently used to analyze the flow, mixing, Combustion, and heat release processes involved. A systematic method is adopted to qualitatively as well as quantitatively investigate different Combustion Modes and their contributions to heat release in the combustor. Influences of airstream temperature and pressure on Combustion Mode and heat release are also discussed by comparing four different cases. Results show that the heat is released from a combination of supersonic Combustion Mode and subsonic Combustion Mode even when the main flow is at supersonic speed. Local Mode transition occurs as the jet flame propagates and interacts with shocks that enhance mixing because of baroclinic effects and induce subsonic Combustion due to deceleration effects. It is also observed that subsonic Combustion releases more than 50% of heat at the base of the jet flame because of recirculation zones behind the strut. Supersonic Combustion Mode gradually becomes prominent in the turbulent far field with small values of heat release rate. The overall dominant Combustion Mode is dependent on not only inflow conditions but also Combustion intensity.
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Investigation on Combustion Mode and heat release in a Model scramjet engine affected by shocks
International Journal of Hydrogen Energy, 2019Co-Authors: Duo Zhang, Donggang Cao, Bing Liu, Fei QinAbstract:Abstract A Model scramjet engine in which the 1.0 Ma hydrogen jet mixes and reacts with the 2.0 Ma surrounding airstream is investigated using large eddy simulation. The flame structure is analyzed with a focus on the relationship between premixed/diffusion Combustion Mode and heat release in the supersonic reacting flow. The flame filter is used to evaluate the contributions to heat release rate by different Combustion Modes qualitatively and quantitatively. Results show that the heat is released from a combination of premixed Combustion Mode and diffusion Combustion Mode even when the fuel and airstream are injected into the combustor separately. Local Mode-transition occurs as the supersonic jet flame propagates and interacts with shocks. The diffusion Combustion Mode dominates during the ignition stage and the premixed Combustion becomes dominant during the intensive Combustion region. When the shock wave impinges on the flame, the Combustion area decreases a little due to the compression effects of the shock. However, the heat release rate is significantly improved in the interaction region since the shock could increase the air entrainment rate by directing the airflow toward the fuel jet and enhance the mixing rate by inducing vorticity due to baroclinic effects, which is good for flame stabilization in the supersonic flow. For the present case, 33.3% of the heat is released by diffusion Combustion and 66.7% of the heat is released by premixed Combustion. Thus the premixed Combustion Mode is dominant in terms of its contributions to heat release in the Model scramjet engine.
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large eddy simulation of flame structure and Combustion Mode in a hydrogen fueled supersonic combustor
International Journal of Hydrogen Energy, 2015Co-Authors: Zhiwei Huang, Fei Qin, Xianggeng WeiAbstract:Abstract In this study, Large Eddy Simulation (LES) of supersonic turbulent mixing and Combustion adopting a Partially Stirred Reactor (PaSR) sub-grid Combustion Model is performed for a hydrogen fueled Model scramjet combustor. The compressible LES solver, which adopts a skeleton of 27 steps and 9 species hydrogen chemical kinetics Model, is used to simulate the flowing and Combustion processes based on structured hexahedral grids. The code is implemented in an Open Source Field Operation and Manipulation (OpenFOAM) solver, and validated against experimental data in terms of mean axial velocity and static temperature at different cross-sections, all show good predictions. An analysis of the flow field is carried out to investigate the supersonic turbulent flame structure and Combustion Mode in the combustor. Mixture fraction is extracted to indicate the reaction progress at different sites, which donates the most likely flame locations when at stoichiometric. Comparison of Combustion parameters including OH mass fraction, scalar dissipation rate, flame index and heat release rate spatial distribution reveals that the supersonic Combustion has the characteristics of a turbulent diffusion flame, where Combustion is held at non-premixed Mode controlled by turbulent mixing in the shear layers. A time scale analysis, the Damkohler Number is performed to examine these reactive zones in more detail. The role of auto-ignition in flame stabilization and lift-off is revealed.
Wen Bao - One of the best experts on this subject based on the ideXlab platform.
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effect of mach number and equivalence ratio on the pressure rising variation during Combustion Mode transition in a dual Mode combustor
Aerospace Science and Technology, 2018Co-Authors: Chenlin Zhang, Juntao Chang, Wen Bao, Jingfeng TangAbstract:Abstract Experiments of equivalence ratio linear increasing are utilized to employ to investigate the characteristics of Combustion Mode transition. For the experiments with kerosene of different increasing slope, it is found that the fuel equivalence ratio has a significant impact on pressure rising slope variation during Combustion Mode transition. In the experiments, the big equivalence ratio slope would not lead to slope variation of pressure rising. Similarly, this phenomenon also could not occur under some high Mach number of incoming flow experiments. Different equivalence ratio slope would lead to different border shape of the boundary layer. And the border shape of the boundary layer and normal shock wave at thermal throat restrains the main flow is an important factor to alter the pressure. Gas dynamics analysis is employed to explain the effect of the boundary layer on the pressure rising slope variation. Further, the analysis also reasonably explains that incoming flow Mach number impacts on pressure rising slope variation.
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pressure rising slope variation accompanying with Combustion Mode transition in a dual Mode combustor
Aerospace Science and Technology, 2017Co-Authors: Chenlin Zhang, Juntao Chang, Shuo Feng, Junlong Zhang, Wen BaoAbstract:Abstract Direct-connect experiment with equivalence ratio linear increasing in a dual-Mode combustor with a strut is conducted at free stream Mach number of 2.0. Based on the pressure histories on side wall, pressure rising slope variation accompanying with Combustion Mode transition is found and discussed. The pressure rising has different slopes vary as equivalence ratio linearly increasing. Meanwhile, this characteristic of pressure slope variation leads to the change of combustor thrust. By analyzing the Combustion heat release zone and the geometric configuration combustor, a typical simplified geometric Model is proposed and studied by using numerical simulation. The phenomenon of the pressure rising slope variation is obtained and explained by the shock train movement in numerical simulation. In the process of shock train movement, a normal shock is established at thermal throat to make the airflow of throat position reach critical state, which could limit the mass flow rate of the supersonic mainstream. Further, inviscid and isentropic flow analysis is employed to illustrate the variation of pressure rising resulted from the occurrence of a normal shock wave. The analysis indicates that the cross-sectional area of mainstream is bounded by the subsonic boundary layer plays a key role to alter the pressure rising slope.
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Experimental study on Combustion Modes and thrust performance of a staged-combustor of the scramjet with dual-strut
Acta Astronautica, 2016Co-Authors: Qingchun Yang, Khaled Chetehouna, Nicolas Gascoin, Wen BaoAbstract:Abstract To enable the scramjet operate in a wider flight Mach number, a staged-combustor with dual-strut is introduced to hold more heat release at low flight Mach conditions. The behavior of Mode transition was examined using a direct-connect Model scramjet experiment along with pressure measurements. The typical operating Modes of the staged-combustor are analyzed. Fuel injection scheme has a significant effect on the combustor operating Modes, particularly for the supersonic Combustion Mode. Thrust performances of the combustor with different Combustion Modes and fuel distributions are reported in this paper. The first-staged strut injection has a better engine performance in the operation of subsonic Combustion Mode. On the contrast, the second-staged strut injection has a better engine performance in the operation of supersonic Combustion Mode.
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Nonlinear characteristics and detection of Combustion Modes for a hydrocarbon fueled scramjet
Acta Astronautica, 2015Co-Authors: Cong Zhang, Juntao Chang, Qingchun Yang, Jingfeng Tang, Wen BaoAbstract:Abstract An experimental investigation of Combustion Mode transition in a hydrocarbon fueled scramjet combustor Model is reported under Mach number 2.1 and 2.5 inflow conditions. Three different Combustion Modes with respect to equivalence ratio are observed, namely, scramjet Mode, weak ramjet Mode and strong ramjet Mode. The typical features of different Combustion Modes are analyzed by wall-pressures and one-dimensionally estimated Mach number distributions. The processes of Combustion Mode transitions show significant nonlinear characteristics. The static pressure and Mach number have discontinuous sudden changes as the Mode transition occurs, especially near the fuel-supply region, emphasizing the importance of detection and control of Combustion Modes. The nonlinear characteristics of wall-pressures near the exit of the isolator can be used in the detection of different Combustion Modes. A series of experiments prove that this pressure-magnitude-based detection technique is feasible.
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Experimental study on Combustion Mode transition effects in a strut-based scramjet combustor
Proceedings of the Institution of Mechanical Engineers Part G: Journal of Aerospace Engineering, 2014Co-Authors: Qingchun Yang, Juntao Chang, Youhai Zong, Wen BaoAbstract:A strut-based scramjet combustor was operated in three different Combustion Modes under Mach 2.5 inflow conditions, scramjet Mode, weak ramjet Mode, and strong ramjet Mode. The Combustion Mode transition effects are investigated through ground experiments. The scramjet Mode occurred below the overall fuel equivalence ratio of around 0.44. Transition from the scramjet Mode to the weak ramjet Mode occurred at ER ∼ 0.44, accompanied by a sudden increase in thrust. By contrast, transition from the weak ramjet Mode to strong ramjet Mode occurred at ER ∼ 0.6125, accompanied by a sudden decrease in thrust. In particularly, Combustion Mode transitions significantly change the dominant characteristics of the flow field.
Juntao Chang - One of the best experts on this subject based on the ideXlab platform.
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Study on influencing factors of Combustion Mode transition boundary for a scramjet engine based on one-dimensional Model
Aerospace Science and Technology, 2020Co-Authors: Ruifeng Cao, Juntao ChangAbstract:Abstract Combustion Mode transition is an important way for a dual-Mode scramjet engine to obtain the high engine performance in a wide operating range of flight Mach number. In this study, the influencing factors on the Combustion Mode transition boundary for the scramjet engine was investigated based on a one-dimensional Model proposed earlier by the authors. The definition of the Combustion Mode transition boundary was described. The effect of the duct area profile of the combustor, the heat release distribution in the combustor, the wall temperature and wall roughness of the combustor and the air composition of the incoming flow on the Combustion Mode transition boundary were analyzed. The result showed that the variation of these factors will make the Combustion Mode transition boundary deviate from the design value. The influencing rules found in this study will provide some theoretical foundations for designing the engine structure and the Combustion Mode transition control scheme of the scramjet engine.
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effect of mach number and equivalence ratio on the pressure rising variation during Combustion Mode transition in a dual Mode combustor
Aerospace Science and Technology, 2018Co-Authors: Chenlin Zhang, Juntao Chang, Wen Bao, Jingfeng TangAbstract:Abstract Experiments of equivalence ratio linear increasing are utilized to employ to investigate the characteristics of Combustion Mode transition. For the experiments with kerosene of different increasing slope, it is found that the fuel equivalence ratio has a significant impact on pressure rising slope variation during Combustion Mode transition. In the experiments, the big equivalence ratio slope would not lead to slope variation of pressure rising. Similarly, this phenomenon also could not occur under some high Mach number of incoming flow experiments. Different equivalence ratio slope would lead to different border shape of the boundary layer. And the border shape of the boundary layer and normal shock wave at thermal throat restrains the main flow is an important factor to alter the pressure. Gas dynamics analysis is employed to explain the effect of the boundary layer on the pressure rising slope variation. Further, the analysis also reasonably explains that incoming flow Mach number impacts on pressure rising slope variation.
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pressure rising slope variation accompanying with Combustion Mode transition in a dual Mode combustor
Aerospace Science and Technology, 2017Co-Authors: Chenlin Zhang, Juntao Chang, Shuo Feng, Junlong Zhang, Wen BaoAbstract:Abstract Direct-connect experiment with equivalence ratio linear increasing in a dual-Mode combustor with a strut is conducted at free stream Mach number of 2.0. Based on the pressure histories on side wall, pressure rising slope variation accompanying with Combustion Mode transition is found and discussed. The pressure rising has different slopes vary as equivalence ratio linearly increasing. Meanwhile, this characteristic of pressure slope variation leads to the change of combustor thrust. By analyzing the Combustion heat release zone and the geometric configuration combustor, a typical simplified geometric Model is proposed and studied by using numerical simulation. The phenomenon of the pressure rising slope variation is obtained and explained by the shock train movement in numerical simulation. In the process of shock train movement, a normal shock is established at thermal throat to make the airflow of throat position reach critical state, which could limit the mass flow rate of the supersonic mainstream. Further, inviscid and isentropic flow analysis is employed to illustrate the variation of pressure rising resulted from the occurrence of a normal shock wave. The analysis indicates that the cross-sectional area of mainstream is bounded by the subsonic boundary layer plays a key role to alter the pressure rising slope.
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Nonlinear characteristics and detection of Combustion Modes for a hydrocarbon fueled scramjet
Acta Astronautica, 2015Co-Authors: Cong Zhang, Juntao Chang, Qingchun Yang, Jingfeng Tang, Wen BaoAbstract:Abstract An experimental investigation of Combustion Mode transition in a hydrocarbon fueled scramjet combustor Model is reported under Mach number 2.1 and 2.5 inflow conditions. Three different Combustion Modes with respect to equivalence ratio are observed, namely, scramjet Mode, weak ramjet Mode and strong ramjet Mode. The typical features of different Combustion Modes are analyzed by wall-pressures and one-dimensionally estimated Mach number distributions. The processes of Combustion Mode transitions show significant nonlinear characteristics. The static pressure and Mach number have discontinuous sudden changes as the Mode transition occurs, especially near the fuel-supply region, emphasizing the importance of detection and control of Combustion Modes. The nonlinear characteristics of wall-pressures near the exit of the isolator can be used in the detection of different Combustion Modes. A series of experiments prove that this pressure-magnitude-based detection technique is feasible.
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Experimental study on Combustion Mode transition effects in a strut-based scramjet combustor
Proceedings of the Institution of Mechanical Engineers Part G: Journal of Aerospace Engineering, 2014Co-Authors: Qingchun Yang, Juntao Chang, Youhai Zong, Wen BaoAbstract:A strut-based scramjet combustor was operated in three different Combustion Modes under Mach 2.5 inflow conditions, scramjet Mode, weak ramjet Mode, and strong ramjet Mode. The Combustion Mode transition effects are investigated through ground experiments. The scramjet Mode occurred below the overall fuel equivalence ratio of around 0.44. Transition from the scramjet Mode to the weak ramjet Mode occurred at ER ∼ 0.44, accompanied by a sudden increase in thrust. By contrast, transition from the weak ramjet Mode to strong ramjet Mode occurred at ER ∼ 0.6125, accompanied by a sudden decrease in thrust. In particularly, Combustion Mode transitions significantly change the dominant characteristics of the flow field.
Xiaojian Yang - One of the best experts on this subject based on the ideXlab platform.
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SI and HCCI Combustion Mode Transition Control of an HCCI Capable SI Engine
IEEE Transactions on Control Systems Technology, 2013Co-Authors: Xiaojian Yang, Guoming G. ZhuAbstract:The Combustion Mode transition between spark ignition (SI) and homogeneous charge compression ignition (HCCI) Combustion of an internal Combustion (IC) engine is challenging due to the distinct engine operating parameters over the two Combustion Modes and the cycle-to-cycle residue gas dynamics during the Mode transition. The control problem becomes even more complicated for a multicylinder engine without camless variable valve actuators. This paper studies the Combustion Mode transition problem of a multicylinder IC engine equipped with dual-stage valve lift and electrical variable valve timing (VVT) systems. Hardware-in-the-loop (HIL) simulations were used as a tool to develop and validate the proposed control strategies. Based on the HIL simulation results, this paper shows that smooth Combustion Mode transition can be realized in a few engine cycles. During the Mode transition, a Model-based linear quadratic tracking strategy was used to track the desired engine manifold pressure through the engine throttle control to maintain the engine AFR in a desired range; the fuel quantity of individual cylinder was controlled via the iterative learning; and engine spark was maintained for the SI-HCCI (or spark assistant) hybrid Combustions during the Combustion Mode transition. The HIL simulations demonstrated the effectiveness of the developed control strategies under both steady state and transient engine operating conditions. As a result, it is feasible to have a smooth Combustion Mode transition for an HCCI capable SI engine equipped with dual-stage valve lift and electrical VVT systems.
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ACC - Air-to-fuel ratio regulation during SI to HCCI Combustion Mode transition using the LQ tracking control
2012 American Control Conference (ACC), 2012Co-Authors: Xiaojian Yang, Guoming G. Zhu, Xuefei ChenAbstract:The Combustion Mode transition between spark ignition (SI) and homogeneous charge compression ignition (HCCI) Combustions of an internal Combustion (IC) engine is challenging due to the distinct engine operating parameters over the two Combustion Modes and the cycle-to-cycle residue gas dynamics during the Mode transition. The control problem becomes even more complicated for a multi-cylinder engine without camless valve actuation. This paper studies the Combustion Mode transition problem of a multi-cylinder IC engine with dual-stage valve lift and electrical variable valve timing (VVT) systems. Hardware-in-the-loop (HIL) simulations were used to develop and validate the proposed control strategies. The HIL simulation results show that smooth Combustion Mode transition can be realized utilizing the hybrid Combustion Mode in a few engine cycles and in-cylinder air-to-fuel ratio during the Mode transition needs to be regulated to the desired level. This paper presents a Model based linear quadratic tracking strategy to track the desired air-to-fuel ratio by controlling the engine throttle. The HIL simulations demonstrated the effectiveness of the developed control strategies. As a result, it is feasible to have a smooth Combustion Mode transition with dual-stage valve lift and electrical VVT systems.
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SI and HCCI Combustion Mode Transition Control of a Multi-Cylinder HCCI Capable SI Engine via Iterative Learning
ASME 2011 Dynamic Systems and Control Conference and Bath ASME Symposium on Fluid Power and Motion Control Volume 2, 2011Co-Authors: Xiaojian Yang, Guoming G. ZhuAbstract:The Combustion Mode transition between spark ignition (SI) and homogeneously charged compression ignition (HCCI) Combustions of an internal Combustion (IC) engine is challenging due to the distinct engine operational parameters over these two Combustion Modes and the cycle-to-cycle residue gas dynamics of the HCCI Combustion. The control problem becomes even more complicated when multi-cylinder operation is involved. This paper studies the Combustion Mode transition problem of a multi-cylinder IC engine with dual-stage valve lifts and electrical variable valve timing systems. A control oriented engine Model was used to develop a multistep Mode transition control strategy via iterative learning for Combustion Mode transition between SI to HCCI with minimal engine torque fluctuations. The hardware-in-the-loop (HIL) simulations demonstrated the effectiveness of the developed control strategy for the Combustion Mode transition under both constant load and transient engine operational conditions.