Ultra High Efficiency Engines and Fuels for Future Low Carbon Vehicles

Professor Hua Zhao, together with Dr Jun Xia, Professor A. Cairns and Dr A. Pesiridis (Department of Mechanical, Aerospace and Civil Engineering) has been awarded a major research grant to the value of £1.04million from the EPSRC to research and develop a novel internal combustion engines for future low carbon vehicles.

The project will be carried out in the Centre for the Advanced Powertrains and Fuels, a research theme in the Institute of Energy Future and is part of a consortium comprising University of Brighton, University of Oxford and UCL, which will investigate how to improve the operation of internal combustion engines by as much as one third efficiency and how new fuels' performance can be used in future engines to bring emissions close to zero.

A number of recent national and international reports have concluded that internal combustion (IC) engines will be the dominant power plant in automobiles for the next few decades and further improvements in the efficiency of IC engines are the most effective way to minimise the CO2 emissions from automobiles. Amongst many potential fuel saving technologies, engine downsizing and regenerative energy recovery are considered to be the two most effective and practical means to lead to large volume production low carbon vehicles in the short to medium terms. The aggressive downsizing (the replacement of a bigger engine with a smaller turbocharged engine) of a four-stroke gasoline engine at 50% has a potential fuel saving of 25%. However, aggressive downsizing to 50% and beyond presents severe challenges because of the maximum capability of boosting devices, knocking combustion, transient performance, high peak cylinder pressure and associated mechanical and thermal load.

The 2-stroke engine has double the firing frequency of the 4-stroke, for the same output torque the 2-stroke engine IMEP and the peak pressure are approximately halved and the safety margin from combustion knock is wider. Therefore the 2-stroke engine has a much greater potential than the 4-stroke engine for more aggressive downsizing, without having to increase boost to the same level as the 4-stroke engine, thereby making the engineering challenges are more realistic and easier to deal with. However, in order to avoid the shortcomings of the conventional 2-stroke engines, the 2-stroke Boosted Uniflow Scavenged Direct Injection Gasoline (BUSDIG) engine has been proposed. New combustion process and control techniques will be researched and developed in order to realise the full potential of the BUSDIG engine. Furthermore, novel air hybrid engine operating concepts will be studied and exploited to enable the uniflow scavenged 2-stroke engine to be operated as a most efficient compressor/expander for further improvement in fuel economy by regenerative energy recovery.

The research project at Brunel is to carry out research on new combustion processes and their control techniques, novel and cost-effective air hybrid engine concepts to maximise the fuel economy benefits of a highly downsized boosted uniflow scavenged DI gasoline (BUSDIG) engine. The research will involve fundamental studies of the flow and combustion process and research of air hybrid engine technologies.
It will be accomplished by both thermodynamic analyses of engine performance and scientific studies of in-cylinder flow and combustion processes through advanced laser diagnostic and modelling techniques.

For more information contact hua.zhao@Brunel.ac.uk