Fuel injection performance and spray characteristic of high‐pressure common rail systems at low temperatures

Abstract

The fuel injection performance and spray characteristics of the high‐pressure common rail (HPCR) system at low temperatures are investigated with experiment. The effects of environmental temperature, common rail pressure, and fuel injection pulse width on the injection quantity and spray characteristics are discussed. The fuel injection quantity at −30°C decreases by about 10% compared to the target fuel quantity. For the different target fuel quantity, the decrease of fuel injection quantity with temperature is the same under different rail pressures. The impact of temperature change on fuel injection quantity is relatively greater when the fuel injection pulse width is small. At the same common rail pressure and injector control pulse width, the injection quantity of −35# diesel is greater than that of −10# diesel for the same temperature condition. The low‐temperature fluidity can ensure normal diesel supply and injection in the fuel supply system. When the viscosity of diesel fuel rises and fluidity deteriorates in a low‐temperature environment, the spray beam produced by the same spray pressure becomes difficult to spread, and the spray penetration distance and cone angle decrease. The spray penetration distance differs by about 2.2 mm between the two temperatures. At low temperatures, the viscosity of diesel fuel rises and the fluidity deteriorates. The minimum injection pressure of the spray increases, and the spray angle is relatively small.