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1 stratified fuel injection FSI
Introduction:
FSI Fuel Stratified Injection is the acronym, which means fuel stratified injection. Layered Fuel injection technology is calculated to analyze precisely controlling the injection quantity into the cylinder combustion mixture to increase the proportion of fuel that the engine, thereby increasing engine efficiency is a technique using the electronic chip EFI engine. Compared to
with the conventional art fuel into an intake manifold of the engine, the engine main advantage FSI are: good dynamic response, can improve the power and torque while reducing fuel consumption.
conventional gasoline engines camshaft position is to collect relevant data, and a computer to control the engine through the fuel injector injected into the intake manifold. Gasoline start mixing within the manifold, and then into the combustion cylinder. Best air mixing ratio with gasoline is 14.7 / 1 (also called theoretical air-fuel ratio), because the traditional gasoline engine with air in the intake manifold mix into the inner tube, it is necessary to achieve the theoretical air-fuel ratio to get better power and economy . However, since the nozzle a certain distance away from the combustion chamber, the mixing of fuel with air is greatly influenced by the valve and the intake air flow switch, and fine oil particles adsorbed on the wall of the pipe, the theoretical air-fuel ratio which is very difficult to achieve, which is a technical problem with the conventional engine difficult to solve.
The direct injection of fuel into the cylinder can solve this problem. Direct injection gasoline engine fuel supply using techniques similar to diesel engines, provide more than 100bar pressure required by a high pressure pump pumps the fuel to provide an electromagnetic fuel injector located within the cylinder. Then the computer-controlled fuel injector in the most appropriate time directly into the combustion chamber, through the design of the internal shape of the combustion chamber, so that the mixed gas can produce a strong vortex of air and fuel mix. And then the region around the spark plug to have a richer mixture, the surrounding region other than the lean mixture, ensures a smooth ignition ofAchieve as much as possible in case of lean combustion.
FSI engine combustion modes:
Theoretically, FSI combustion engine has at least two modes: the stratified combustion and homogeneous combustion, the homogeneous combustion mode was also subdivided into homogeneous lean mode and a homogeneous combustion mode. Fuel Stratified Injection FSI represents the meaning from the point of view, should be the essence of the stratified combustion characteristics FSI engine, but it can also be understood as a starting point for research and development and infrastructure.
stratified combustion:
advantage stratified combustion is characterized by high thermal efficiency, low throttling losses, limited as much as possible of the fuel is converted into work energy. The stratified combustion mode, the throttle valve is not fully open, ensure a certain degree of vacuum in the intake pipe (exhaust gas recirculation may be controlled and the canister etc. means). In this case, the engine torque is dependent on the size of the fuel injection amount, the intake air amount and the ignition advance angle has little relationship.
In the stratified combustion mode during an intake throttle valve opening degree is relatively large, reducing the portion of throttling losses. Key intake process is disposed in the intake manifold a replica replica open up (the principles of the nature of the actual models may vary) is sealed at the intake manifold, so that the intake air accelerated by, the Omega; shaped piston top fitting, complementary intake swirl.
stratified combustion when the fuel injection time in the top dead point before 60deg; 45deg ;, before top dead injection time has a great influence on the formation of air-fuel mixture, fuel is injected in the pit of the piston top, spray a fuel vortex is formed in conjunction with the intake air-fuel mixture. Mixture formation occurs at a crank angle 40 deg; to 50 degrees; the range, if less than this range, the mixed gas can not be ignited if it exceeds, it becomes a homogeneous state. Stratified combustion air-fuel ratio is generally between 1.6-3. Ignition, only around the spark plug is preferably a mixed state of gas is ignited, when the fresh air and the gas around the exhaust gas recirculation is formed from a well insulated protective, reducing the cooling cylinder arm, improved thermal efficiency. Ignition timing control is also very important, the compression only in a very narrow range ending process.
the lean homogeneous:
the homogeneous lean mode mixture formation for a long time, uniform combustion, by precisely controlling the fuel injection, the mixed gas can reach the lowerconcentration. Ignition timing broad range of homogeneous lean, good fuel economy.
the lean homogeneous combustion and stratified same intake process, oil extended mixing time, to form a homogeneous mixture. Combustion occurs throughout the combustion chamber, the ignition timing is not required for stratified combustion less stringent. A lean homogeneous air-fuel ratio is greater than 1.
homogeneous combustion:
homogeneous combustion is able to give full play to the dynamic response, high torque and power characteristics. Homogeneous combustion during the intake throttle position determined by the accelerator pedal, a replica of the location in the intake manifold depending on circumstances. Among isochronous load, a replica is still closed, favors the formation of a strong cyclonic flow into, conducive to the formation of mixed gas atomization. When the high speed high load, replica opened, the intake air amount is increased, so that more air is involved in combustion. Fuel injection homogeneous combustion, and the combustion gas mixture is formed with substantially the same as the homogeneous lean mode. The homogeneous combustion air-fuel ratio is less than or equal to 1.