Current directions in LD powertrain technology in response to stringent exhaust emissions and fuel efficiency requirements

The major global automotive markets have all set limits for exhaust emissions from new road vehicles, which have become increasingly stringent over the past few decades. There is also considerable pressure to reduce fuel consumption and CO2 emissions – around 80% of all new passenger cars sold globally are subject to some kind of energy efficiency regulation. Such legal requirements necessitate extensive R&D and testing and the entire field is undergoing a period of rapid change. Despite a recent trend towards harmonisation, at present significant regional differences exist, which vary from the analytical laboratory methods specified, the list of regulated pollutants, the numerical values of the emissions limits and the test cycles employed for engine and chassis dynamometer testing of vehicles and their powertrains. Here the key points are reviewed and strategies and technologies employed to deal with these emissions challenges are discussed. Incoming automotive emissions regulations including the WLTP and Real Driving Emissions are discussed and in conclusion likely directions in powertrain technology are identified.