Gas engine air-fuel ratio oxygen storage percentage target compensation control system and strategy

The invention discloses a control system and strategy for air-fuel ratio oxygen storage percentage target compensation of a natural gas engine, and the control system and strategy are realized by applying the control system, and the control strategy comprises the following steps: when the natural gas engine runs, measuring the air-fuel ratios at an inlet and an outlet of a three-way catalyst through a front oxygen sensor and a rear oxygen sensor; the rich condition of air-fuel ratio control of the engine body is fed back through a measured value of the rear oxygen sensor; an ROL target compensation curve calibrated in the ECU is inquired by adopting an average value of oxygen concentrations which are measured in real time continuously for N times, so that an ROL target compensation value is obtained to correct and calculate an ROL target value; and comparing the corrected and calculated ROL target value with an actual ROL value, calculating the correction amount of the previous oxygen concentration, and final