Research On Diaphragm Pump Driven By Plane Cam For DME Engine

Dimethyl Ether (DME) has many advantages, such as high efficiency, low emissions, lownoise, smokeless and so on, which make it a promising alternative fuel in diesel engine. With itsunique physical-chemical characteristics, when applying it in diesel engine, the NOx emissioncan be lower, and nearly smokeless. That effectively solves the contradiction which can notreduce PM and NOx emissions at the same time. However, when using DME in traditionaldiesel engine, plunger of injection pump can be severely worn in a short period, due to the lowviscosity of DME. As a result, serious leak comes out and finally injection pump can not worknormally.In order to solve the problem above, our research group has developed planecam-diaphragm type fuel pump, based on DME engine low-pressure fuel delivery system. Themain characteristics of fuel pump is that its transmission system is improved, based on thetraditional hydraulic diaphragm pump. The planar cam transmission mechanism of VE pump isused as transmission mechanism of fuel pump. The problem of leakage plunger wear is solvedby diaphragm of diaphragm pump, because it can separate the plunger and DME. Plane cammechanism has many advantages, such as small size, stable, reliable, high fuel. It can solve theProblem that the diaphragm pump can not be used in DME engine because of large size.The planar cam transmission mechanism and hydraulic diaphragm pumps are analyzed inthis paper, according to which, the simulation model of this system has established by AMESim.Pressure, flow, leakage characteristics of fuel pump are mainly deeply researched systematically.The batch of plunger stroke, the plunger radius, cam speed and other parameters is analyzed.With the methods of comparison and optimization, the optimization results, including thestructural parameters of the plane diaphragm fuel pump cam are gained. One the one hand, thisresearch provides theoretical guidance for the research of DME engine plane cam pump’sminiaturization; on the other hand, it laid the foundation for the research of DME enginelow-pressure common-rail performance.