Tom Shenton

Laser ignited engines: progress, challenges and prospects.

Laser ignition (LI) has been shown to offer many potential benefits compared to spark ignition (SI) for improving the performance of internal combustion (IC) engines. This paper outlines progress made in recent research on laser ignited IC engines, discusses the potential advantages and control opportunities and considers the challenges faced and prospects for its future implementation. An experimental research effort has been underway at the University of Liverpool (UoL) to extend the stratified speed/load operating region of the gasoline direct injection (GDI) engine through LI research, for which an overview of some of the approaches, testing and results to date are presented. These indicate how LI can be used to improve control of the engine for: leaner operation, reductions in emissions, lower idle speed and improved combustion stability.

Multi-point laser spark generation for internal combustion engines using a spatial?light modulator

This paper reports on a technique demonstrating for the first time successful multi-point laser-induced spark generation, which is variable in three dimensions and derived from a single laser beam. Previous work on laser ignition of internal combustion engines found that simultaneously igniting in more than one location resulted in more stable and faster combustion – a key potential advantage over conventional spark ignition. However, previous approaches could only generate secondary foci at fixed locations. The work reported here is an experimental technique for multi-point laser ignition, in which several sparks with arbitrary spatial location in three dimensions are created by variable diffraction of a pulsed single laser beam source and transmission through an optical plug. The diffractive multi-beam arrays and patterns are generated using a spatial light modulator on which computer generated holograms are displayed. A gratings and lenses algorithm is used to accurately modulate the phase of the input laser beam and create multi-beam output. The underpinning theory, experimental arrangement and results obtained are presented and discussed.

Advanced Powertrain Control Strategies

Abstract The development process for powertrain control systems is intensive of time, effort and skill. With the availability of integrated CAE tools for control system design, simulation and implementation the automotive industry is moving towards model based design and analysis techniques to speed development and provide more robust control solutions. Today’s CAE tools provide flexibility and offer considerable scope to evaluate and test advanced control methods. This paper discusses the application of these tools to a project concerned with the evaluation of different control methods for an engine idle speed problem.

Multiple Pulse Laser Ignition in GDI Lean Combustion

Laser Ignition (LI) is a new, innovative technology which overcomes several limitations of conventional spark ignition; it presents many potential advantages for engine dynamic control, especially for gasoline direct injection engine. This paper highlights a new approach, using principle component analysis of the pressure curve, to dynamically control multiple pulse laser ignition (MPLI). In the results, experimental data presents how the control of MPLI improves the performance of the engine and demonstrates the effectiveness of MPLI in lean combustion. This work is part of an Engineering and Physical Sciences Research Council funded research project which is to investigate how optimised control strategies, including multiple stratified fuel injection (MSFI); MPLI and multiple location laser ignition (MLLI), can help to improve the stability of leaner operation and reduce the emissions. The possible future of LI dynamical control strategies is discussed.

Multiple Pulse Laser Ignition Control Application in GDI Lean Combustion

This paper highlights a new innovative approach to create and control multiple pulse laser ignition applied on a GDI engine. The results present the dual pulse effectiveness in super lean condition and it indicates the dual pulse has significantly improved the engine stability.

Diffractive Multi-point Laser ignition of internal combustion engines using a spatial light modulator

We generated diffractive multi-beams for laser ignition using a spatial light modulator (SLM). Breakdown sparks with arbitrary geometrical location were created. The multi-beam patterns were delivered to engine for ignition tests without clipping.

Optimal Input Design for Dynamic Model Prediction Accuracy

Abstract A new optimality criterion for the optimal input design for discrete dynamic nonlinear system identification is presented. The criterion weights the parameter covariances by the magnitude of regressors in order to reduce the prediction error. An iterative optimization procedure to the optimal signal design is proposed. The effectiveness of the optimal test signal design is demonstrated by the system identification and validation of a nonlinear multiple-input single-output (MISO) automotive engine fuelling model. The output-error simulation accuracy of the resulting model is compared with those of models identified by means of commonly used non-optimal test signals and optimal signals designed by alternative optimality criteria. The proposed test signal design method is shown to provide superior outcomes in output prediction fit and also to allow the application of input and output constraints as required for experimental industrial applications.