Research on Pressure Control of High Pressure Oil Pipe Based on Mass Conservation

Abstract

为了研究高压油管内压力的稳定问题，基于质量守恒原理，本文运用燃油量周期不变、周期分割、压力按周期等量划分的思想，建立了质量守恒模型。首先通过拟合弹性模量和压力的关系，建立密度与压力的微分方程。再计算进油量，根据质量守恒方程求得单向阀每次开启时长。根据不同调整时间算出喷油器工作周期数，得出2 s、5 s、10 s下每次单向阀开启时长。根据考虑柱塞腔与针阀控制的高压燃油系统工作原理，考虑在1 s的总时长下，高压油管的压力保持稳定，求出单周期下的喷油量。对于供油柱塞，计算得到下止点时充满柱塞腔的燃油质量。最后根据质量守恒求得周期数，得到凸轮角速度。 In order to study the stability of high pressure oil pipe pressure, based on the principle of mass conservation, a mass conservation model is established by using the idea of fuel quantity period constant, period segmentation and pressure division by period. Firstly, the differential equation of density and pressure is established by fitting the curve of elastic modulus and pressure. After that we calculate the oil inflow together with the length of each check valve by using the mass conservation equation. According to the different adjustment time, the number of working cycles of the injector is also calculated, hence the length of each check valve opening is obtained for 2 s, 5 s and 10 s, respectively. In the light of the working principle of the high-pressure fuel system, the plunger chamber and the needle valve control, it is considered that the pressure of the high-pressure fuel pipe is kept stable under the total length of 1 s, while the fuel injection amount in a single cycle is obtained. For the oil supply plunger, the fuel mass filled in the plunger chamber at the bottom dead center is also obtained. Finally, the number of cycles is computed following the conservation of mass, and further the cam angular velocity is obtained.