Oil And Gas Quantity Adjustment Control And Software Development Of Diesel/CNG Dual Fuel Engines

In order to improve the technical level of China’s diesel engine, meet the user’s actualneeds and the requirements of the Euro III emission regulations, this paper based on the levelof current diesel engine, researched electronic-controlled technology of diesel/CNG dual fuelengine that will provide an basis for improving existing diesel/CNG dual fuel engine level anddeveloping more advanced electronical-controlled dual-fuel engine and promoting to broadenthe diesel vehicle market channels, change the car energy system and solve exhaust pollutionproblem.Relied on the Science and Technology Department Shaanxi Province “Throttle DrivingControl Device of Natural Gas/diesel Dual-fuel Vehicle” project, this paper converted purediesel engine into diesel/CNG dual fuel engine and studied control strategies and sofewaredevelopment of diesel/CNG dual fuel engine. In order to ensure the feasibility of the projectimplementation, in this paper, the diesel injection system used mechanical and electrical jointcontrol solution; diesel came from fuel pump, natural gas controlled by a solenoid valve.Codewarrior software platform, as the development tool of Freescale MC9S12DG128,Freescale C as the programming language, this paper researched the following four conditions:starting and warming, stable idle, intermediate running and overspeed protection,designeddual-fuel engine speed interrupt service program, the sensors analog signal acquisition andprocessing program for different working conditions’ program etc. PID algorithm incrementalis used to correction and adjustment. In the conditions of starting and overspeed protection,the open-loop control algorithm is used. Closed-loop control is used in idle and intermediateconditions to regulate separately the engine speed and the throttle stick position.Commissioning tests by fuel injection equipment is accomplished. Signal generatoranalog signals of speed sensor, rotary potentiometer analog gas pressure sensor and thecooling water temperature sensor. Through debugging the control strategies’ test of dual-fuelmode, the results show that control strategies meet engine operating conditions according toadjusting the position of the throttle and natural gas injection valve.