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

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 algorithms 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 behavior of engine follows the characteristic,that is,"forward-reverse-forward".The reversal range is between 65～75,°CA,and the maximum reversal speed is 70,r/min.The forward range is between 2～ 5,°CA,and the maximum forward speed is 40,r/min.The stop behavior is that piston-connecting rodcrankshaft-flywheel and its surrounding become the dissipative system of surplus kinetic energy.