Design Of Fuel Injection Control System For Marine Dual Fuel Engine

Energy crisis and environment pollution are the two main problems which restrict social sustainable development. The increasing strict emission regulation has made the oil-used internal combustion engine in a awkward position. CNG gets special attention for its advantages such as high energy density, low emission and high reserves, in the context of energy saving and emission reduction. CNG vised as an alternative fuel in diesel is widely researched around the world. In our research we change an marine diesel engine into an dual-fuel-engine, develop an dual-fuel inject control system and study the economic and emission performance of dual-fuel engine.According to the research of predecessors and appeal of gasification of Yangtze River, we transform a Weichai X6170ZC-05W diesel which is the mainstream engine on river boat. On the principle of keep the original machine unchanged, we add CNG supply system on the inlet manifold.According to need of system we choose a Freescale 16bits MCU as a core control chip. We design the controller under the guide of modular and universal design thought so that we can use the same controller in two different gas supply system. On the basic of hardware we develop the software under the guide of hierarchical and modular design thought, priority and task scheduling is used.Combining the features of marine engine we design the operation condition identification and gas injection strategy. We analysis the design methods of oil gas shift, speed signal process, gas inject timing, control of solenoid driven, control of gas quality and communication calibration.We carny out experiment to verify the performance of dual-fuel engine. According to the diesel propulsion characteristic, we conducted a series of contrast experiment under diesel only and dual-fuel mode. By comparing the experiment result of single-point and multipoint at same operation condition we study the dynamic property, economic and emission property and alternative ratio of dual-fuel engine. The result shows that dual-fuel engine have the same dynamic property as the primary engine and the NOx and soot emission decreased obviously, the HC and emission temperature increased. But the economic and emission performance is better than diesel only mode as a whole. When alternative ratio is 65% the dynamic property, economic and emission performance, operation stability are in better station. So it is efficient for double fuel to improve the economic and emission of the engine.