发动机活塞位置全工况测量系统设计与试验

Design and Experimental Investigation of Engine Measurement System of Piston Position Under All Operating Conditions

设计的发动机活塞位置全工况测量系统利用特定的二进制信号靶盘及光电传感器来突破传统磁电传感器频率响应下限,并设计活塞位置标定表和相应算法,满足了直喷汽油机瞬时反转直接起停系统对工况的拓展,可全工况实时监测发动机活塞位置、相位、正反转信号和转速.同时建立了直喷发动机停机试验台架,并在冷却水温度90,℃时进行无负载停机试验.结果表明,发动机停机行为遵循"正转-反转-再正转"的停机特征.经统计,反转幅度在65～75,°CA,反转最高转速达到70,r/min,之后的再次正转幅度在2～5,°CA,再次正转最高转速为40,r/min.发动机停机行为是活塞-连杆-曲轴-飞轮系统受摩擦和缸内所封住气体的影响,与周围环境构成停机剩余动能的耗散系统.

The measurement system of engine piston position under all-operating condition was designed. Using specific binary coded target and photoelectric sensors, the lower frequency limit of traditional magnetoelectric sensor was broken, and the piston position calibration table and the corresponding algo- rithms table was designed, so the development of operating conditions for instantaneous reverse direct start ＆ stop system of gasoline direct injection engine was covered, which meant piston position, phase, rotate direction signal and rotate speed can be measured under all operating conditions. The test bench for stopping test was established by gasoline direct injection（GDI）engine, and the stopping test without load when the temperature of cooling water is 90℃ was made. The test result shows that stop be- havior of engine follows the characteristic, that is, ＂forward-reverse-forward＂. The reversal range is be- tween 65- 75℃A, and the maximum reversal speed is 70 r/min. The forward range is between 2 5℃A, and the maximum forward speed is 40 r/min. The stop behavior is that piston-connecting rod- crankshaft-flywheel and its surrounding become the dissipative system of surplus kinetic energy.