Research Of Diesel Cylinder Deactivation Technology Based On GT-Power And Simulink

With the continuous increase of vehicle holdings in China, energy saving and emission reduction of engines has become an extremely urgent matter. In order to improve fuel economy of engines, cylinder deactivation technology has been used on engines at the beginning of the 20th century. However, it is mainly used in gasoline engines and marine diesel engines; and much of the literature has indicated that the application of cylinder deactivation technology in gasoline engines can improve the fuel economy effectively. The use on diesel engines is very limited because there is no throttle valve which causes pumping loss before cylinder deactivation. But there is still research value. After some of the cylinders are deactivated it is necessary to increase output power of the remaining cylinders to ensure that the total output power is constant as before, and then the diesel engine can be made to work in the area of higher fuel economy. The main research contents are as follows:(1) The model of a diesel engine was established by GT-Power software, selecting engine heat transfer model, fuel injection model and combustion model, imputing relative parameters, adjusting initial conditions and boundary parameters of each module, and verifying that the model is correct.(2) On the basis of the established GT-Power model of the diesel engine, it has been modified to realize cylinder deactivation technology.(3) Choosing different cylinder deactivation ways including that one cylinder and two cylinders were deactivated to simulate the diesel engine in several work conditions: 1600r/min,2000r/min,2400r/min and 3200r/min with 25% load and fuel economy was compared.(4) Selecting the cylinder deactivation mode with a better fuel economy, analyzing emission characteristics, cylinder deactivation working area and the influence of cylinder deactivation position to the diesel engine.(5) An integrated simulation platform was built to achieve the transient control of the cylinder deactivation with GT-Power and Simulink.(6) Work processes of the diesel engine from the original machine to two cylinders deactivated and from two cylinders deactivated to the original machine were simulated under 25% load of 2400r/min speed, and the influence of different control strategies on the diesel engine cylinder deactivation has been analyzed.The research shows:(1) Stopping off the fuel injection to deactivate cylinders cannot reduce the fuel consumption rate, and thus the mode on the diesel engine is not available;(2) The fuel economy of the diesel engine can be improved effectively by stopping valves to achieve cylinder deactivation. Compared to the case with one cylinder deactivated, the fuel saving effect is better with two cylinders deactivated, and NOx emission has a rise of 10%, and soot emission has a decline of 35%.(3) Based on stopping valves the cylinder deactivation was simulated. It shows that different positions of deactivated cylinders have a very small impact on fuel economy. But considering output torque smoothness, cylinder position with uniform ignition interval should be chosen to be deactivated. Thus, the third cylinder is chosen during one cylinder deactivated, and the second cylinder and the third cylinder are chosen during two cylinders deactivated.(4) From the work without cylinder deactivated to the work with two cylinders deactivated, there is a sudden drop on the output torque and the drop reaches 60% if there is no special control. To reduce the drop rate during the conversion process, the increasing rate of fuel injection mass of working cylinders should be improved and the injection timing should be advanced appropriately.(5) From the work with two cylinders deactivated to the work without cylinder deactivated, the output torque dropped to about 35% of the original torque suddenly and then it suddenly increased to about 135% of the original torque. To ensure the rapid recovery and vibration amplitude of diesel engine torque during cylinder deactivation recovery process, the decreasing rate of the fuel injection mass of the working cylinders should be improved.