The author considers the rapid rate of advance in technologies associated with exhaust emissions which has brought compliance with regulations ahead of time. Reducing nitrogen oxides and particulates simultaneously has been a particularproblem. Research into improved combustion however has brought improved fuel consumption as well. The role of the speed of injection in minimising nitrogen oxides is discussed and improvements made to injection systems in the last few years outlined. The advantages of the electronic control of injection are considered. The role of fuel quality is briefly examined. The engines emerging tend towards high torque at low speed and a slow governed speed. Areas where further research is expected are outlined including after-treatment de)
Abstract