David Dyntar

Modellbasierte Steuerung und Regelung eines Erdgasmotors

SAE technical paper series, Mar 4, 2002

CNG engines are now recognized to be an interesting alternative to classical IC engines because o... more CNG engines are now recognized to be an interesting alternative to classical IC engines because of low pollutant and carbon dioxide emissions. This paper will first briefly summarize these advantages quantitatively and then concentrate on the modeling and the control of CNG engines. In the modeling part it will be shown which effects are similar to SI engines and what new submodels are necessary. In the control part the problem of sudden A/F ratio changes (for instance during the regeneration of NOx trap catalysts) will be considered. In these transients it is important to switch from lean to rich conditions within few combustion cycles (in order to avoid excessive NOx engine-out emissions) while keeping the engine torque constant (for comfort reasons). The paper presents a model of the most important phenomena associated with that transient and a feedforward control that meets the mentioned requirements. Both simulation results and experimental validation will be shown.

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Optimal Control for Bouncing Suppression of CNG Injectors

Journal of Dynamic Systems Measurement and Control-transactions of The Asme, Mar 1, 2004

This paper describes the model-based design and the experimental validation of a control system w... more This paper describes the model-based design and the experimental validation of a control system which suppresses the bouncing behavior of Compressed Natural Gas (CNG) fuel injectors. First a detailed model of the system is developed, including temperature and supply-voltage variation effects. Using an optical position sensor, this model is experimentally validated in a second step. Based on this model a feed-forward controller is developed and tested which minimizes the bouncing energy of the system. Since in series applications position sensing would be too expensive to use, an observer-based iterative control algorithm is derived which uses coil current measurements instead of the position information to asymptotically suppress bouncing.

Clean Engine Vehicle A Natural Gas Driven Euro-4/SULEV with 30% Reduced CO2-Emissions

SAE technical paper series, Mar 8, 2004

The goal of the Clean Engine Vehicle project (CEV) was the conversion of a gasoline engine to ded... more The goal of the Clean Engine Vehicle project (CEV) was the conversion of a gasoline engine to dedicated natural gas operation in order to achieve a significant reduction in C0 2 emissions. The targeted reduction was 30% compared with a gasoline vehicle with similar performance. Along with the reduction in emissions, the second major requirement of the project, however, was compliance of the results with Euro-4 and SULEV emission limits. The project entailed modifications to the engine and the pre-existing model-based engine control system, the introduction of an enhanced catalytic converter and downsizing and turbocharging of the engine. As required by the initiators of the project, all components used were commonly available, some of them just being optimized or modified for natural gas operation. Such technology represents one of the cleanest powertrains for motor vehicles, especially if an effectbased assessment of exhaust emissions regarding greenhouse gases, ozone-forming potential, acid formation and toxic exhaust emissions is considered.

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Modellbasierte Steuerung und Regelung eines Erdgasmotors

The present thesis is a contribution to the research efforts dealing with the injection of natura... more The present thesis is a contribution to the research efforts dealing with the injection of natural gas and its combustion within an engine. It introduces a new kind of accurate discrete event Modell of fuel dynamics, which can not only be used for natural gas engines. A feedforward controller for the fast A-switchbased on this modell has been developed and sucessfully tested. A lean-bum spark ignition engine saves fuel. This is also true for an engine powered by natural gas. However, the emission limits of the future cannot be met by lean-bum engines alone [36, 41]. Rather, special catalytic converters with storage capabilities will have to be utilized as well. With lean-bum engines, such catalysts work effectively for a few tens of seconds only, after which they regularly have to be regenerated for a few seconds with rich exhaust gas. Unless special precautions are taken, these periodic so-called lambda switches cause unacceptably high torque disturbances, which seriously affect th...

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A method for driving an electromagnetically actuated pilot valve and to a plant with such a switching valve

A method for driving a blocking a pressurized fluid flow and releasing electromagnetically actuat... more A method for driving a blocking a pressurized fluid flow and releasing electromagnetically actuated switching valve having a solenoid which acts on a movable valve body and the current is supplied to the valve-operating with a coil current, wherein the current supply having a rising and a falling pulse edge with the coil current, characterized in that a distance from a switching edge (11, 12) of the valve-actuating coil current (10) an air movement of the valve body braking braking pulse (13, 14) of the current supply is superimposed, wherein the brake pulse is determined so that the energy of the valve body, upon reaching a stop on the minimizing end of the flight movement, wherein the current flowing through the solenoid coil current is measured and the energy of the flight movement of the valve body from the coil current (I) is derived.

Verfahren zum Ansteuern eines elektromagnetisch betätigten Schaltventils sowie eine Anlage mit einem solchen Schaltventil

Die vorliegende Erfindung betrifft ein Verfahren zum Ansteuern eines elektromagnetisch betatigten... more Die vorliegende Erfindung betrifft ein Verfahren zum Ansteuern eines elektromagnetisch betatigten Schaltventils sowie eine Anlage mit einem solchen Schaltventil. Bei einem Verfahren zum Ansteuern eines Schaltventils wird durch ein elektromagnetisch betatigtes Schaltventil eine druckbeaufschlagte Fluidstromung, wie eine Gasstromung, gesperrt oder freigegeben. Hierzu wirkt ein Elektromagnet auf einen beweglichen Ventilkorper ein. Er wird zur Ventilbetatigung mit einem Spulenstrom 10 bestromt, wobei die Bestromung mit dem Spulenstrom 10 eine ansteigende und eine abfallende Schaltflanke 11 bzw. 12 aufweist. Beabstandet zu einer Schaltflanke 11, 12 des ventilbetatigenden Spulenstroms 10 wird ein die Flugbewegung des Ventilkorpers bremsender Bremsimpuls 13, 14 der Bestromung uberlagert.

Hybrid Wave Engine Concept and Numerical Simulation of Engine Operation

Archive of Mechanical Engineering, 2010

Recent investigations of micro engines have documented the problem of low efficiency of steady co... more Recent investigations of micro engines have documented the problem of low efficiency of steady compression devices [2]. As a solution, the application of unsteady processes has been proposed [1, 6, 17-20]. Closer investigations have shown the applicability of pure unsteady devices for gas compression, but it is also shown that they are practically not applicable for torque generation [21]. A new concept of the wave engine has to be developed. This paper presents such a new concept and numerical investigation of the hybrid wave engine. A hybrid wave engine combines in a single machine components realizing unsteady compression, steady expansion, and mixed unsteady and steady scavenging due to the centrifugal force action. MEMS technology requires or prefers a flat geometry. Therefore, the use of a radial type of wave compression device for air compression is proposed. A numerical, two-dimensional complete model of this device was built, and several numerical simulations of engine operations were performed. The numerical model includes the simplified model of the combustion chamber closing the flow loop between the high-pressure compressed air port and the high-pressure hot exhaust gas port. The model represents the complete flow scheme of the hybrid wave engine. A special type of turbine in radial configuration with serial flow layout is used for torque generation.

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Modeling and Control of CNG Engines

SAE Technical Paper Series, 2002

CNG engines are now recognized to be an interesting alternative to classical IC engines because o... more CNG engines are now recognized to be an interesting alternative to classical IC engines because of low pollutant and carbon dioxide emissions. This paper will first briefly summarize these advantages quantitatively and then concentrate on the modeling and the control of CNG engines. In the modeling part it will be shown which effects are similar to SI engines and what new submodels are necessary. In the control part the problem of sudden A/F ratio changes (for instance during the regeneration of NOx trap catalysts) will be considered. In these transients it is important to switch from lean to rich conditions within few combustion cycles (in order to avoid excessive NOx engine-out emissions) while keeping the engine torque constant (for comfort reasons). The paper presents a model of the most important phenomena associated with that transient and a feedforward control that meets the mentioned requirements. Both simulation results and experimental validation will be shown.

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Optimal Control for Bouncing Suppression of CNG Injectors

Journal of Dynamic Systems, Measurement, and Control, 2004

This paper describes the model-based design and the experimental validation of a control system w... more This paper describes the model-based design and the experimental validation of a control system which suppresses the bouncing behavior of Compressed Natural Gas (CNG) fuel injectors. First a detailed model of the system is developed, including temperature and supply-voltage variation effects. Using an optical position sensor, this model is experimentally validated in a second step. Based on this model a feed-forward controller is developed and tested which minimizes the bouncing energy of the system. Since in series applications position sensing would be too expensive to use, an observer-based iterative control algorithm is derived which uses coil current measurements instead of the position information to asymptotically suppress bouncing.

Ultra-high-energy-density converter for portable power

Mesoscale gas turbine generator systems are a promising solution for high energy and power densit... more Mesoscale gas turbine generator systems are a promising solution for high energy and power density portable devices. This paper presents an overview of a two-stage system with a power output of 100 W. There is a need for catalytic combustion and new ceramic materials. An existing turbine expander and a compression system are downscaled and a high-speed test-bench setup for the electrical system has been built. A simulation toolbox for small thermal machines and model-based control and diagnostics are developed.

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Hybrid Wave Engine Concept and Numerical Simulation of Engine Operation

Archive of Mechanical Engineering, 2010

Recent investigations of micro engines have documented the problem of low efficiency of steady co... more Recent investigations of micro engines have documented the problem of low efficiency of steady compression devices [2]. As a solution, the application of unsteady processes has been proposed [1, 6, 17-20]. Closer investigations have shown the applicability of pure unsteady devices for gas compression, but it is also shown that they are practically not applicable for torque generation [21]. A new concept of the wave engine has to be developed. This paper presents such a new concept and numerical investigation of the hybrid wave engine. A hybrid wave engine combines in a single machine components realizing unsteady compression, steady expansion, and mixed unsteady and steady scavenging due to the centrifugal force action. MEMS technology requires or prefers a flat geometry. Therefore, the use of a radial type of wave compression device for air compression is proposed. A numerical, two-dimensional complete model of this device was built, and several numerical simulations of engine operations were performed. The numerical model includes the simplified model of the combustion chamber closing the flow loop between the high-pressure compressed air port and the high-pressure hot exhaust gas port. The model represents the complete flow scheme of the hybrid wave engine. A special type of turbine in radial configuration with serial flow layout is used for torque generation.

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Numerical investigation of the Wave Disk Micro-Engine concept

International journal of gas turbine, propulsion and power systems, 2008

This paper presents results of numerical investigation, based on two-dimensional model, of a wave... more This paper presents results of numerical investigation, based on two-dimensional model, of a wave disk micro-engine concept taking into account full set of unsteady, centrifugal, Corriolis forces existing in such configuration. Even in two-dimensional simplification, the engine model derived guarantees conservation of mass flow through the simulated combustion chamber. A series of different geometrical configurations is analyzed. Investigation concentrates on the pure unsteady wave engine configuration. The waveengine design investigation presented in recent paper focused on two main problems: realization of gas compression and simultaneously a torque generation. Compression performance has been confirmed in almost any considered configuration but the torque generation was much below the expectations. Results of numerical simulations are presented in form of pressure, temperature and velocity distributions as well torque variations.

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Numerical investigation of the Wave Disk Micro-Engine concept

International Journal of Gas Turbine, Propulsion and Power Systems, 2008

This paper presents results of numerical investigation, based on two-dimensional model, of a wave... more This paper presents results of numerical investigation, based on two-dimensional model, of a wave disk micro-engine concept taking into account full set of unsteady, centrifugal, Corriolis forces existing in such configuration. Even in two-dimensional simplification, the engine model derived guarantees conservation of mass flow through the simulated combustion chamber. A series of different geometrical configurations is analyzed. Investigation concentrates on the pure unsteady wave engine configuration. The waveengine design investigation presented in recent paper focused on two main problems: realization of gas compression and simultaneously a torque generation. Compression performance has been confirmed in almost any considered configuration but the torque generation was much below the expectations. Results of numerical simulations are presented in form of pressure, temperature and velocity distributions as well torque variations.

Download

Clean Engine Vehicle A Natural Gas Driven Euro-4/SULEV with 30% Reduced CO2-Emissions

SAE Technical Paper Series, 2004

The goal of the Clean Engine Vehicle project (CEV) was the conversion of a gasoline engine to ded... more The goal of the Clean Engine Vehicle project (CEV) was the conversion of a gasoline engine to dedicated natural gas operation in order to achieve a significant reduction in C0 2 emissions. The targeted reduction was 30% compared with a gasoline vehicle with similar performance. Along with the reduction in emissions, the second major requirement of the project, however, was compliance of the results with Euro-4 and SULEV emission limits. The project entailed modifications to the engine and the pre-existing model-based engine control system, the introduction of an enhanced catalytic converter and downsizing and turbocharging of the engine. As required by the initiators of the project, all components used were commonly available, some of them just being optimized or modified for natural gas operation. Such technology represents one of the cleanest powertrains for motor vehicles, especially if an effectbased assessment of exhaust emissions regarding greenhouse gases, ozone-forming potential, acid formation and toxic exhaust emissions is considered.

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