A measurement method for the dual fuel coupling injection characteristics of the high-pressure natural gas and diesel co-direct injection engine

This paper presents an innovative measurement method for a two-phase fuel transient flow rate in the same space-time dimension. Based on the jet momentum measurement, a spray filter is designed to realize the space extraction of the target jet. The optimized jet baffle structure is proposed, which greatly improves the quality of the test signal. Compared with the pressure-time method, this method has higher precision in the gas injection rate shape measurement and the recognition precision of gas injection beginning and ending moment. The coupling effect of two-phase fuel injection and the influence of different ambient pressures on injection performance can be studied by this method. The results show that the pilot diesel injection will cause more than 20% fluctuation of gas injection mass, and the ambient pressure can promote the gas needle opening, which will significantly affect the fuel injection mass of the engine.

Automated summary

This paper presents an innovative measurement method for a two-phase fuel transient flow rate in the same space-time dimension. Through jet momentum measurement and the design of a spray filter, the method enables spatial extraction of the target jet. With the optimized jet baffle structure, the quality of the test signal is greatly improved. Compared with traditional methods, this method has higher precision in measuring the shape of gas injection rate and recognizing the beginning and ending moments of gas injection. It can also be used to study the coupling effect of two-phase fuel injection and the influence of ambient pressure on injection performance.