Research On Controllable Supercharging System Of Gasoline Engine

Downsizing gasoline direct engine with charger is a trend of the development of contemporaryengine. Through reducing engine displacement to improve economy, then charging to enhance its powerperformance. This technology is accepted by the worldwide related enterprises and research institutions.Such as Volkswagen’s1.4TSI engine, using the combination of turbocharged and gasoline direct injectionmakes full use of1.4L engine’s power performance, the economy is also better than the same powerperformance of large displacement naturally aspirated engines. It largely improved the engine’s power perliter.Traditional gasoline direct injection engine with charger technology are based on the turbocharger,but for many years turbocharger was not widely used by gasoline engines because throttling loss causedby throttle has serious influence on the supercharger, just because of throttling, which makes turbochargernot play its due role, As the turbocharger is driven by exhaust to provide impetus turbine rotation, andsupercharges intake by rotating impeller. Because of this, turbocharger must always access, and can’tdisconnect, no matter how much throttle percentage it always compress intake.For supercharged engine, supercharger is rotated by power passed out by crankshaft. It is linkedthrough the pulley or gear, which decides its connection between crankshaft and supercharger. Based onthe characteristics, this paper studies a controllable supercharged mode which adds an electromagneticclutch on the basis of the traditional supercharger. It can quickly and efficiently control the connection ofsupercharger with crankshaft, by means of this controlling whether to compress intake. At the same timewe also study a control mode which is different from the traditional supercharger.It is variable speed ratiosupercharger, as follows:1.Using the traditional supercharger, it’s difficult to give consideration on different requirement forthe amount of intake air when the engine works at low or high speed condition. Low speed ratio canimprove the intake efficiency when the engine works at high speed but it can not provide enough fresh airfor its poor condition contributed by the low charger speed. When the speed ratio increased, the speed ofcharger is enhanced accordingly so that it can work on a better state and the performance of the enginecan be improved. The increase of the speed ratio also result in high speed of charger that consume of thepower will rise, which will block the improvement of engine’s performance.2. Pass-off supercharger can be used to cut down the negative influence of the throttle. At part load,the naturally aspirated engine. At full load, the supercharger will benefit the economy of the part load andthe dynamic of the high load. Innovatively propose a new control strategy. Intervention of thesupercharger will attribute the sudden improvement of the motive power when the throttle is opencompletely. Lacking smooth transform will affect engine performance greatly. 3. The first section of Chapter four of this article, a controlled opening of the intake pressure reliefvalve was introduced in the back end of the turbocharger, by controlling the opening of the pressure reliefvalve to control the inlet pressure. This allows throttle inlet pressure gradually increased, so that theengine power can be a smooth transition.4. In part two Chapter four, a variable transmission pattern of the supercharger which based on theelectromagnetic clutch control of the supercharger is put forward. For the sudden change of motive power,the pressure ratio of the mechanical supercharger can be changed by changing the transmission ration.This variable pressure ratio can make the supercharger’s pressure increased gradually when the throttleopen completely, making the transition of the engine smooth. When the engine needs more power you canraise the supercharger’s pressure ratio by changing the speed ratio, effectively enhance the amount offresh air into the cylinder. This will provide more power for the car. Intake air naturally can reduce theconsumption of the petrol great when there is no need for too much power, making the goal of high fueleconomy and good power performance.