Intake Valve Deposit Testing Using an Engine Dynamometer Procedure

The use of 1985 BMW 318i vehicles is the most widely used method for the measurement and study of intake valve deposits in automotive gasoline engines. An alternative test procedure has been developed employing a 1985 2.3L Ford engine on an engine dynamometer which correlates with the BMW method, and has good statistical repeatability. The 112 hour test uses a two phase cycle with engine conditions controlled to enhance formation of dry and carbonaceous deposits. This test procedure has been successfully applied to two additional engine types, and also can be used to study the influence of gasoline composition on intake valve deposits and to measure octane requirement increases.