Research On Control System Of Dual Fuel Engine

With the worsened the air pollution and petroleum shortage, a kind of alternative fuel—Liquefied Petroleum Gas (LPG) as a valid solution, is attracting more and more attention. Diesel engine has been used in many fields and is playing an important role in people's life, so to develop a dual fuel engine from the base of diesel is a concernful research direction for engines which consume alternative fuel.Based on the paper [15], a solution for dual fuel engine was provided, which control the quantity of diesel fuel injected into the cylinder precisely by an electronic governor. In this solution, this governor control the rack directly, the structure is very compact with a small quantity of mechanical parts and the parts are easy to be machined, the actuator can link the rack without any clearance and this is advantageous to improve quality of control. This solution is very valuable in engineering application.Based on the engine internal diagram a dynamical physical model was built. This model can reflect the fluctuating of transient speed and the effect of parameters of PID control. So with this model, simulation for some key parameters was realized. The result of the simulation can direct the research work of electronic control system for engine.The jerk pump was redesigned and the original mechanical governor was replaced with an electromagnetic actuator and its sensor. With JiangKui's ECU and based on PID, a digital electronic governor was developed. With this governor, the control system is more flexible than mechanical one, and engine can be used in many fields without any modifying.The control of quantity of dual fuel injected was realized based on the electronic governor. This system can adjust the ratio between these two fuels according to the driver's meaning and the current load of engine. With this system, the dual fuel engine can be put into practice.Wire pedal was realized in this system. With this function, engine can be optimized by calibration according to the character of main equipment, and this is also beneficial to reduce the harmful gas exhausted and make the main equipment more economical and powerful.The result of the engine performance test showed that this system can not only control the quantity of LPG and diesel fuel injected automatically, but also can optimize the performance of the diesel engine.At the end of this paper, a summarization was presented and the work direction of next step is discussed.