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High engine efficiency and low emissions on spark ignition engines can be achieved with a new camshaft profile switching device. This enables the use of two camshaft profiles for inlet and exhaust that can be switched independent of each other by any engine management input. This paper proposes the use of this device to give an excellent torque curve together with reduced emissions, by selecting from two discrete inlet and exhaust camshaft profiles and timings against engine parameters such as speed, load and temperature.

In order to reduce the development time involved in optimising the combustion system and valve timing of the internal combustion engine, an electro-hydraulic valve actuation system has been developed. The effects of various combustion strategies, including asymmetrical valve events, on emissions and efficiency, together with their sensitivity to EGR and AFR were investigated. In addition, the influence of the cylinder head design on in-cylinder charge motion and combustion was investigated by correlating airflow, tumble and swirl data to the heat release data obtained during dynamometer testing.