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The open MAHLE Flexible ECU (MFE) was developed and successfully implemented for controlling gasoline, diesel and hybrid engines. The increased demand of new functions development to address future powertrain challenges, such as lower fuel consumption, ever more stringent emissions legislative targets as well as the need to reduce development time and cost at the same time, led to the incorporation of the MFE functions in a co-simulation environment. The co-simulation environment consists of using the virtual engine developed with 1D or 3D numerical simulation tools and the functions of MFE developed with Simulink-Targetlink. This co-simulation approach allows modifying either the engine control or the engine itself. Regarding the engine control and its development, the existing and new functions were tested for the performance, emissions and behaviour changes on several production and prototype engines.

Downsizing of the spark ignition engine is accepted as a key contributor to reducing fuel consumption. Turbocharged engines are becoming commonplace in passenger vehicles, replacing naturally aspirated larger capacity engines. However, turbocharged engines have typically suffered from “lag” during transient operation. This perceived effect is a combination of the low speed steady state torque and a slower rate to reach maximum torque during a load step. In order to increase customer acceptance of downsized concepts it is vital that the low speed torque and transient response are optimized. Variable Length Intake Manifolds (VLIM) have long been an established method of improving the full load performance of naturally aspirated engines. The manifold length being “tuned” to provide a high-pressure pulse at intake valve closing to maximize cylinder filling and deliver improved performance.

The need to meet ever more stringent emission legislations over the last decade has led to a significant increase in diesel engine complexity. A typical modern passenger car diesel engine now features variable geometry exhaust gas turbocharging and variable charge motion in combination with exhaust gas recirculation. Further improvements are still required and one technology that has the potential to improve fuel economy and reduce emissions is variable valve timing. This gives the ability to alter in-cylinder charge motion and effective compression ratio. In doing so, it not only alters in-cylinder pressures and temperatures, but also the operating point of the turbocharger and EGR system. This paper demonstrates how both 1-D and 3-D numerical simulation have been used in conjunction with engine testing to analyse the fundamental effects and separate the interactions.

1D wave action simulation has been used to construct models of a number of turbocharged spark ignition engines. This paper describes how the models have been applied in the development of those engines. The simulation has been used to optimise a number of components including the inlet and exhaust manifolds, the valve timing and the turbo match. The models have been validated against test data. The method of modelling unsteady flow is described and the behaviour of the turbocharger in unsteady flow investigated.