Development of an electronic control unit for a compressed natural gas engine, based on circuit simulation and modelling

Abstract

An electronic control unit (ECU) is designed for a compressed natural gas (CNG) engine on the basis of circuit simulation and modelling. The ignition drive circuit and power-off delay circuit are discussed, with emphasis on circuit simulation, and resistance matching for the sensor processing circuit is described. Design of the software of the CNG control system is based on modelling. A TargetLink model of an air—fuel ratio closed-loop control system is presented. The CNG ECU has been applied successfully in bench tests. The results of bench tests have shown that the hardware meets CNG control system requirements; actuators can be controlled precisely, and the performance of the CNG engine can reach design targets. Circuit simulation and modelling are good methods for developing the ECU design for CNG engine systems. Quality of hardware and software design can be ensured, and the development cycle and costs can be reduced.