Deposit induced runaway surface ignition may be avoided by proper engine design and maintenance, and in many cases by controlling the quantity of lubricant ash consumed by the engine. This can be done by maintaining good oil control for minimum engine wear and maximum cleanliness. The paper examines theories as to how deposit induced runaway surface ignition occurs, and reports the results of tests on truck and passenger car engines, and a single cylinder COT engine. Results indicate that deposit induced runaway surface ignition is affected by the type of combustion chamber deposits made by the fuel lubricant combination, by the deposit heating characteristics of the fuel and air mixture, and by the hot spot characteristics of the fuel air charge.
