Effects of a Wide Range of Drive Cycles on the Emissions from Vehicles of Three Levels of Technology

Exhaust emission tests were performed on a fleet of vehicles comprising a range of engine technology from leaded fuel control methods to closed loop three-way catalyst meeting 1992 U.S. standards but marketed in Australia. Each vehicle was tested to 5 different driving cycles including the FTP cycles and steady speed driving. Research had shown that for hot-start operation the major driving pattern parameters which influence fuel consumption and exhaust emissions are average speed and PKE (the positive acceleration kinetic energy per unit distance). Plots from analysis of micro-trip fuel use and emissions rates from the test cycles may be presented as contours in PKE. It follows that the micro trip emissions from a range of driving cycles including, regulated e.g. FTP city and unregulated e.g. LA-92, recently developed EPA cycles or from other cities e.g. Bangkok can be superimposed. The implications of stop-go driving can be graphically depicted and compared with smooth driving such as the U.S. highway cycle. It is concluded that: the latest technology vehicles, whilst emitting at lower levels have emission rates more sensitive to high accelerations (PKE) than older technology vehicles; the conditions for minimum emissions change with vehicle technology; and regulating vehicle acceleration and speed can be a beneficial emission reduction strategy.