Automotive powerplant evaluation

A program to obtain automotive engine performance data for use in estimating vehicle emission and fuel economy in varied service and duty is described. An experimental test procedure for generating fuel consumption and emissions data adequate to characterize an engine over its full operating range was developed for steady-state tests. The development of a test procedure for transient testing is currently under way. The steady-state data will be collected from approximately 23 different engines, including: (1) 16 current production spark-ignition engines; (2) 3 pre-production or prototype advanced design spark-ignition engines; and (3) 4 light-duty diesel engines which are, or could be, used in passenger car applications. To date, steady-state ''engine maps'' were completed on 10 engines. A simplified model used to compare steady-state data with chassis dynamometer data indicates that results thus far can be used to obtain estimates of fuel economy in automobiles.