Browse Publications Technical Papers 2019-32-0579

Calcium in Oil Effects on Pre-ignition of Two-stroke Engine 2019-32-0579

Investigations of the influence of calcium on pre-ignition in a two-stroke engine have shown that the lower the calcium concentration, the lower the frequency of pre-ignition. Pre-ignition problems can occur in small, air-cooled, two-stroke engines such as a chainsaw. In contrast, in a supercharged automobile engine, it has been reported that calcium, which is a detergent component in engine oil, causes low-speed pre-ignition. The oil for two-stroke engines also contains calcium and is mixed with the fuel and lubricated before being supplied to the combustion chamber. This makes, two-stroke engines more likely to be affected by oil components. Based on this, we investigated the influence of calcium on pre-ignition of a two-stroke engine. First, we investigated driving conditions in which pre-ignition is likely to occur, such as warming up the engine. Under this condition, oil with calcium concentrations ranging from 0 ppm to 1,500 ppm were tested at a mixing ratio of 2%. The results show that the lower the calcium concentration, the lower the incidence rate of pre-ignition. Which could also occur at 0 ppm. The incidence rate was 4.6% at 1,500 ppm and 2.3% at 0 ppm.


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