Study On Calibration Methods Of Electronic Control System For Gasoline Engine Based On Uniform Design

With the improving requirements on automotive engines performances for emissions, econocimic, security and drivablility, Electronic Control Systems (ECS) have already been an inevitable choice for modern engines. The gradually improved system function enables the control strategies more complicated and the number of the related control parameters increased rapidly. Traditional ECS calibration have shown two notable characteristics: one is the experiments design still rests on comprehensive design, orthogonal design so that the number of test points grows exponentially or squared with control parameters and nodes; the other is that test methods mainly adopts trails and errors. Therefore, calibration with high accuracy and precision demands extensive input of time and capital, and hardly completes the experiments within the increasingly urgent product development cycles. Thus systematic study and reform for the calibration technology is imperative.The research work and the results include: (1) By taking 479Q gasoline engine as the research object, using the open ECU with host computer control system developed by our studying team, a test bench was builded. (2) Based on the study on the structure and principle of sensors and actuators of ECS, experimentally calibrated the working characteristics. (3) Through analysis on output signal waveform of crankshaft position sensor and camshaft position sensor, top dead center on compression stroke of 1# cylinder located at 118.5CA after teeth mark was determined, while the output signal wave of camshaft position sensor was high potential, and the engine operation synchronization was completed. (4) According to the external characteristic and theoretical model builded, initial control MAPs for injection pulse width and volume efficiency were obtained. (5) The quasi-diensional combustion model for spark advance angle was performed. (6) Based on electromagnetic theory, initial control MAPs for close angle were acquired. (7) Prediction with empirical function through bench test, accelerated the basic calibration progress. (8) Adapted to uniform design (30 test points) and polynomial regression models, basic control MAPs for injection pulse width and spark advance angle were successfully obtained, with less error compared with that maked by comprehensive test( 170 test points).After systematic researching bench basic calibration process for ECS, by means of uniform design and empirical function prediction, calibration methods can make full use of existing data and engineers' experience knowledge, ensure not only accuracy and precision, but also reduce workload without restriction by the number of control parameters. It shows an important role and engineering value in speeding up ECS development owing to the calibration time and experimental costs effectively controlled.