高压共轨系统中的燃油温度变化及其影响

In order to explain the effect of fuel temperature on fuel injection quantity, fuel temperature change in high pressure common rail(HPCR) system and its effect on the system were studied. A math model of fuel heat release and heat-exchange in HPCR system was founded, a temperature model was built of the fuel in high pressure pump, common rail and electronically controlled injector, and a simulation model of the fuel heat in HPCR system was set up with the hydraulic fluid calculation software AMEsim. The simulation model was verified with the test data. By means of simulation, fuel temperature variation at outlets of different parts was analyzed. The results show at 400 r/min and 1 600 r/min high-pressure pump speed, the fuel temperature at the pump outlet is increased by 4.5 ℃ and 23.3 ℃ respectively; when the rail pressure is increased from 55 MPa to 140 MPa, the change range of fuel temperature at the rail outlet is only 35~55 ℃; when the rail pressure is 140 MPa, the change range of fuel temperature at the nozzle orifice outlet is 90~110 ℃. The pressure fluctuation in the rail resulting from fuel temperature is smaller when the fuel temperature is at 20 ℃ and 40 ℃, and larger at 60 ℃ and 0 ℃; the fuel injection quantity change due to fuel temperature is larger at low rail pressure and smaller at high rail pressure.