A Research About Control Parameters' On-line Adjustment Technology Of Dual-Fuel Automobile's ECU

It is an important developmental direction to use liquefied petroleum gas and natural gas as automobiles' substitutive fuel in our country. It can decrease emission pollution caused by automobiles and relieve the shortage of energy. However, because of the restriction of gas stations, majority of our country's gas automobiles work on dual fuel form. Presently the main technology devices of refitting dual-fuel automobiles depend on import, and the cost of refitting is very high. In view of the above, Harbin Engineering University has developed a kind of nuclear component of electronic control system-electronic-control-unit (ECU) which owns independent rights. It can control the amount of gas fuel of a dual-fuel automobile. The electronic-control-unit was used to apply to a type of Xia Li automobile once. By the experimental study, it was proved that it had possessed higher standard of control emission, and achieved the Europe standards (II). However, since it hasn't the function of communication, it couldn't adjust the control parameters online when we are refitting a dual fuel automobile from different types of automobiles, and it is very not convenient to make matching experiments. In view of this, in order to complete the functions of the electronic-control-unit and make preparation for its practical application, an on-line adjustment technology of control parameters of dual-fuel automobiles' ECU is worked out in this paper, so the study works have practical significance.The chief study contents and results in this paper are the following:(1) A test-bed of LPG and gasoline dual-fuel system has been set up on 2032SA Beijing jeep, and a series of emission experiments have been done which include the contrast of using petrol and LPG, the contrast of LPG opened loop control system and closed loop control system, et al. The experimental results indicate that the control effects of the ECU are well, and the application prospect is bright. By doing the emission experiments, the control principle of the ECU and the functions of related control parameters are known, and beneficial experience for the developing of on-line adjustment technology of ECU's control parameters is accumulated.(2) Adopting RS-232C interface standard and asynchronous serialcommunication method, the overall scheme of the data communication system between the microcomputer in the ECU and a PC computer were designed.(3) A series of interface electric circuits of the communication system were completed. The communication programs between the microcomputer and a PC computer are worked out. The designs of user interface are reasonable and its functions are integrity. The simulated experimental results indicate that the communication system designed in this paper is reliable and very convenient to use. At the same time it can meet the demands of on-line adjustments for ECU's control parameters.