Cng And Gasoline Dual-fuel Engine Electronic Control Unit Hardware Research

As a green fuel, CNG features less expense and a rather low exhaust pollution compared to gasoline in the engine fuel application. And our country has a large natural gas storage. Thus, applying CNG in automotives could fully utilize the natural gas resource, reduce the exhaust pollution and operating expense of the vehicles.The research of CNG application is just started due to the automotive industry development domestic. Engines specially designed for CNG are rare and the CNG stations are not fully established. So carrying out the application research of CNG based on gasoline engines and developing bifuel engine system for CNG and gasoline has great significance.This dissertation falls into four aspects below:The differences between CNG and gasoline in the engine application and engine performances under different CNG supply methods are discussed. Then the bifuel engine system solution for CNG and gasoline based on AJR 1.8L 2VQSEA 827 NF gasoline is proposed.Handling logics for sensor signals are developed and related hardware interfaces are designed based on the analysis of important sensors and their signal characteristic; the CNG and gasoline injector characteristic and their demand for driving circuit is introduced. Injector driving circuits are designed, which drive the injectors properly and pass the lab test.The demand of hardware reliability design in automotive environment is analyzed from component selection and EMC design aspects; Solution for clock circuit, I/O port circuit and CNG injector circuit is given. And the most emphasis is laid upon the CNG injector driving circuit reliability design.Last, the data acquisition and actuator driving logics, which provide efficient and reliably low level logic for the upper level software in the engine management system, are developed upon the MAC7111 Microcontroller and former described ECU hardware.The ECU hardware with sensor interface and injector driving circuit could fulfill basic function in bifuel engine management under software control. The whole bifuel engine management system could operate reliably in Hardware-in-the-Loop Simulation under lab environment.