LPG AS AN ENGINE FUEL. ENGINE AND CAR TESTS

The aim of this work was to determine the highest possible propylene content of c3-lpg, if the fuel has to be equivalent to premium quality gasoline in a dual-fuel application. Knock tests were made both with a cfr test engine and an ordinary four-cylinder talbot engine. The results of the cfr tests showed that the level of premium gasoline quality can be reached at a propylene content of 20%, whereas the multicylinder test showed that the propylene content should be about 10%. When the propylene content varies from 0 to 50%, the theoretical air-fuel ratio varies from 15.8 to 15.3. The effects of the air-fuel ratio were studied with an engine installed in an engine dynamometer. The influence of the air-fuel ratio on engine performance is small at low load levels, but will increase as does the influence of spark timing with higher loads. Fuel consumption and exhaust gas emissions did not differ essentially from conventional gasoline values. Engine wear and deposits were insignificant in lpg running. (TRRL)