USEFUL test procedures and instrumentation for evaluating the effects of combustion chamber deposits are described here. A multi-cylinder deposit-ignition counter has been developed which detects and records the deposit ignition occurring in the individual cylinders of a multicylinder engine. This new instrument measures basic deposit effects over a wide range of engine operating conditions and can be used either in the laboratory or on the road.
The instrument is useful for studying the effects of fuels, lubricants, and additives in multi-cylinder engines. Since variation among individual cylinders can be detected, the instrument is also useful for studying engine design changes as well as operating conditions.
Road and dynamometer test procedures for evaluating deposit-induced autoignition by the conventional audible method of detection are described along with the effects of several fuel-lubricant-additive combinations.