High Altitude Laboratory Studies of Compression Ignition Engines

An engine is sensitive to its fuel and lubricant. This suggests such problems as wear and deposits, and the modifying conditions of environmental effects which cause cold starting and vapor lock. Another environmental condition not often considered is altitude. This paper discusses very briefly a test facility at Aberdeen Proving Ground that can be used to evaluate the full load performance of an engine at varying altitudes. Altitudes of 12,000 ft can be simulated with a 150 hp engine while maintaining temperatures from −65 F to +120 F. Results for six engines operated in this facility are presented. These engines are all military engines but most have commercial counterparts.

Data show the advantage of turbocharged engines over naturally aspirated engines. However, unless turbocharger is properly matched to engine and environment, gains are negligible. Data on which the paper is based are all normal laboratory measurements (power, fuel flow, temperatures and pressures) and in some cases turbine speeds, air flow and combustion data.