The study of fuel accumulation in the oil of a gasoline engine with direct fuel injection

Abstract

BACKGROUND: The worldwide powertrain engineering tendency is reduction of mass and dimension properties of an engine with simultaneous increase of its specific power and power-to-weight ratio. It can be achieved with compression ratio increase, engine cycle improvement, implementation of supercharging system and direct fuel injection. With the direct injection systems implementation, the issue of fuel accumulation in oil became relevant. AIMS: The article addresses general issues related to fuel accumulation in the motor oil. METHODS: Analysis of the published data addressing this issue. RESULTS: The reasons of fuel entry into oil were formulated, the possible acceptable limits of fuel concentration in oil were defined, and the data of vehicle fleet observation performed by specialists during several years was given. CONCLUSIONS: There is rather considerable range of opinions and recommendations regarding acceptable fuel concentration in oil. Therefore, it may be concluded that the value of fuel concentration in itself makes little difference, and, in order to define the maximal acceptable level of fuel concentration in oil, it is reasonable to carry out studies of determination acceptable limits of particular motor oil properties, primarily viscosity.