STRATIFIED CHARGE TWO-STROKE SPARK:IGNITION ENGINE (RAM STRATICHARGE, VEE-4, 108.6 INT3 DISP.) PERFORMANCE CHARACTERISTICS

摘要

The RAM vee-4, two-stroke stratified charge engine is a spark-ignition, blown, pressure lubricated, port valve engine with a cam actuated auxiliary air inlet poppet valve. It is designed to operate with lean air-fuel ratios, like a compres¬sion-ignition engine, but with a low compression ratio and spark ignition. No carburetor is employed. Either timed or continuous manifold fuel injection upstream from the auxiliary valve may be used. The tests reported here are for continuous injection.nThe engine with the 90° duration cam for the poppet valve has a flat specific fuel consumption curve at approximately 60 lb/shp-hr and hydrocarbon emissions of 2 to 3#. The max¬imum brake mean effective pressure at 2000 rpm was 90 psi. The longer duration cam (120°) results in a somewhat higher specific fuel consumption averaging approximately .63 lb/shp-hr over a smaller range of speeds and torques. Hydrocarbon emissions are higher of the order of 4 to 5％.