The scope for improving the efficiency and environmental impact of internal combustion engines

Currently 99.8% of global transport is powered by internal combustion engines (ICEs) and 95% of transport energy comes from liquid fuels made from petroleum. Many alternatives including battery electric vehicles (BEVs) and other fuels like biofuels and hydrogen are being considered. However, all these alternatives start from a very low base and face very significant barriers to unlimited expansion so that 85–90% of transport energy is expected to come from conventional liquid fuels powering combustion engines even by 2040. Hence it is imperative that ICEs are improved in order to reduce the local and global environmental impact of transport. This paper considers the scope for such improvement after discussing…