New development of piston crown for dual fuel diesel engine to improve efficiency and reduce nox emissions: A review

An engine technology breakthrough is in high demand to balance efficiency and emission levels, and one potential method is to use gas as fuel, such as in dual-fuel (DF) technology. In this research, CNG fuel will be used in a 4-stroke single-cylinder diesel engine. The combustion efficiency will be effected not only by the fuel quantity and quality but also by other processes such as the combustion stoichiometry, fuel, and air mixing, gas, and air, the timing of opening and closing valves, injection timing, etc. Higher combustion may be achieved when the engine geometry is improved to receive a higher energy transfer, but may consequently cause higher forces and require greater strength in the material, with the possibility of causing damage. Increasing the combustion capacity may have a dangerous effect on components such as the piston crown, walls, injector needle, and valves. Such cost is one of the noted weaknesses of the DF diesel engine, and the piston crown is the weakest component. The structure of the crown must be capable of absorbing the thermal impact by sufficient thickness and user profiling. This research work will examine some configurations of the piston crown shape to find the optimum one to deal with the overload that may occur when the combustion is maximized by using a higher proportion of the gas fuel, which is called the un-lean condition. Piston crown modeling and further testing use structural strength and forms analysis software. Related papers and previous research will be reviewed here to enrich the concept.