INFLUENCE OF FUEL PRESSURE PULSATION ON INJECTION CHARACTERISTICS OF CR SYSTEM

Abstract

Fuel injection causes high fuel pressure fluctuations in the tube before the sprayer. If several injections made, the previous injection affects the following injection. The amplitude of the pressure fluctuation is influence by fuel pressure, the size of the first injection portion and the properties of fuel. The aim of the study is to investigate the influence of pressure fluctuations caused by the first (auxiliary) injection on the main portion of fuel. Studies have shown that the amplitude of the pressure fluctuation of the mineral diesel is 6; 11 and 18 MPa at 60, 120 and 180 MPa for injection pressure and 0.3 mS auxiliary injection time. Increasing the duration of auxiliary injection to 0.5 ms, the amplitude of pressure fluctuations changed slightly and reached 6; 10 and 18 MPa. In order to investigate the influence of pressure pulsations on the cyclic fuel content, the time between auxiliary and main injection changed so that in one case the main injection begins due to the pressure fluctuations caused by the auxiliary injection and as the pressure decreases. At a pressure of 60 MPa and an injection duration of 0.3 ms, the cyclic fuel quantity was higher when the main injection occurred during pressure increase. The difference reached 0.22 mg. Meanwhile, the duration of the 0.5 ms auxiliary injection, the cyclic fuel was 1.28 mg higher with pressure decreasing. When the pressure reached 120 MPa, the cyclic fuel at a higher pressure of 0.5 mg increased by 0.3 m and at 0.5 ms, with a decrease in 1.59 mg. At 180 MPa pressure, both values were obtained with higher pressure decreasing - 0.73 and 0.85 mg.