The Development Of Electronic Controlling System For CNG Single Fuel Engine Based On DSPACE

As a new type of clean energy, especially automobile, natural gas has been widely applied to various industries. There are two main types of natural gas engine, that is, single fuel gas engine and dual fuel gas engine. With the development of modern control technology, the air-fuel ratio of engine and emission control is becoming more and more strict, therefore, exploring a CNG engine electronic control unit with market competitiveness has become a major focus in the current.In the face of increasingly complex electronic system, the traditional way of ECU development has many disadvantages, such as long cycle, high cost and difficult to design. Especially for design highly complex and nonlinear engine control unit, no matter software development or testing are getting harder.In this paper, we establish a rapid control prototyping of electronic control unit (ECU) with MATLAB/Simulink software combined with RTI modules in dSPACE system and success to design control algorithm for CNG engine in the form of module block diagram. On the basis of the original control model, the paper include:closed-loop control and self-learning strategy based on UEGO for CNG engine air-fuel ratio control, automatic ignition advance angle calibration system based on feedback speed and CNG engine constant speed control algorithm. For the relationship between speed and throttle under different loads, we carry out the transfer function identification and do a research on the feedback PID simulation control.Based on the analysis of working principle for Bosch LSU4.2UEGO, we develop closed-loop control and self-learning for the air fuel ratio control strategy and achieve the effective control of air-fuel ratio and help the calibration of the injection MAP so that we are not need to accurate calibrate each point. The injection width can be adjusted to the appropriate value rely on closed-loop and self-learning when the engine work and it can save time for MAP calibration, at the same time it also can make up for the air-fuel ratio deviation due to loss of the engine aging.The calibration system of ignition advanced angle based on speed feedback can help the calibration of ignition MAP. The constant engine speed control system is to expand the applicability of the control system. We use PID control strategy to insure the speed steady near the target value through adjusting throttle position real-time. Based on the model of the throttle and the speed feedback PID control simulation is recognized the throttle and the speed transfer function under different load in advance and then the feedback PID control model is established so that it can be convenient to set PID parameters.