Development Of ECU For Compressed Natural Gas Engine

Under the stress of oil supply and consumption, the alternative fuel becomes the new Hotpoint in the automotive area. To meet this requirement, a electronic controlled gaseous injection system for CNG engine was designed and developed in this thesis.Combined with the FAW group subject"development of CNG engine electroniccontrolled system for heavy duty route vehicle", FAW Group plans to produce CNG engine electronic controlled gaseous CNG injection system within three years. Electronic control CNG engine system concludes gaseous CNG injection quantity control and CNG fuel injection timing control. Fuel injection quantity control system was designed primarily in this thesis. A series of work from system configuration, ECU software and hardware development to CAN bus system design were made in this thesis. The development and manufacture of CA6DE2 CNG engine electronic controlled CNG fuel injection system product were focused in this thesis. The basic working principle of CA6SE2‐21CNG engine electronic controlled CNG fuel injection system is showed as following: at first, with engine speed and pedal position signals, normal value of fuel injection quantity is obtained according to MAP figures which is made with engine experiment data and memorized in engine ECU, then, the normal value is modified to target control value by in‐air temperature and pressure signals, at last, fuel injection quantity is controlled according to lambda feedback signal.The software of CNG engine electronic controlled CNG fuel injection system was also designed. This software can meet the requirement of the characteristic of CNG engineElectronic control system has the characteristic of real‐time, multi‐task and random. According to the traits of CNG engine, the design aim and modular concept, the software is divided into fuel inject quantity calculation module, fuel injection timing control module, lambda closed loop control module, ignition angle calculation module, ignition timing control module, ETC control module, main control module and common module. The main control module will administrate other else modules depending on different functions. The results of experiments show that the software is reasonable and efficient.