Pilot Program to Develop Operating Time Emission Degradation Factors for General Aviation Piston Engines.

摘要

A pilot program for investigating the problems associated with the piston engine continuous compliance requirement of the Emission Standards was undertaken at the National Aviation Facilities Experimental Center (NAFEC). The program used two aircraft as test vehicles to determine emission degradation characteristics of piston engines over a time period of 150 hours. This was the initial plan for the program, but due to a proposed modification in the Environmental Protection Agency (EPA) emission standards for piston engines, the program was shortened and terminated after 50 hours on each engine. This report describes the work and results obtained for the 50-hour engine time period. The results indicate that (1) no appreciable change in emissions occurs within the first 50 hours of engine operation, (2) emissions can be measured on aircraft-installed engines with accuracies comparable to those obtained in test stands, provided proper instrumentation and test procedures are used, and (3) aircraft instrumentation is satisfactory for some parameters, but in order to achieve EPA accuracy requirements, manifold pressure, fuel flow, and induction airflow must be measured on laboratory-type instruments. (Author)