1.FSI
FSI, literal translation of the word it represents as the fuel stratified injection, it is a sign of the code Volkswagen direct injection engine. So FSI engine What are the benefits? It’s loaded car can bring us what kind of surprise?
compared to those of the gas injected into the engine intake manifold, the main advantage FSI engine are: good dynamic response, can improve the power and torque while reducing fuel consumption.
Theoretically, FSI combustion engine has at least two modes: the stratified combustion and homogeneous combustion, was also divided into the homogeneous combustion mode and a homogeneous lean mode 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 has the advantage of 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 greater than,It becomes a homogeneous state. Stratified combustion air-fuel ratio is generally between 1.6-3.
When the 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, lift thermal efficiency. Ignition timing control is also very important, the compression only in a very narrow range ending process.
the homogeneous lean mode mixture formation for a long time, uniform combustion, by precisely controlling the fuel injection, to achieve a lower concentration of the mixture. 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 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.
above three FSI engine combustion state is unique to combustion control mode, but some aspects still remain in terms of theoretical advantages. Now Audi FSI engine also released worldwide have adopted the homogeneous combustion mode, this does not mean stratified combustion can not be achieved, but only that the cost or timing of implementation of stratified combustion is not yet ripe. Mainly in the stratified combustion with a lean mixture, to improve the in-cylinder temperature also increases nitrogen oxides such harmful emissions. For lean burn, Common catalytic conversion of nitrogen oxides is difficult to clean and requires the addition of a NOx reduction catalytic converter, and adds to the burden of space and cost. In addition, the high sulfur content of gasoline at this stage this is very damaging to catalytic converters, and therefore there is the transformation of oil refining equipment, improve fuel quality and cost.
is not a stratified combustion will not let FSI launchThe advantages of the original machine gone? the answer is negative. Even without the application of stratified combustion, FSI can improve the compression ratio of the engine as well as to reduce the amount of residual oil combustion characteristics. FSI engine with direct injection, gasoline evaporated in the cooling effect is generated inside the cylinder, thus reducing the likelihood of knocking, it may be appropriate to enhance the compression ratio. When blended with swirl intake valve timing can not obtain a good combustion of the residual oil re-use. In this way, FSI engine still greater as increased power, lower fuel consumption.
FSI effect produced by the engine can be seen from the engine Audi indicators released by the company. 3.2 l and 4.2 l FSI FSI example, contrast the previous model were 3.0 liters and 4.2 liters of gasoline. The power was 3.2 l FSI engine 257 horsepower, improved 39 hp 218 hp compared to the original model, 350 hp engine FSI 4.2 liters up to 15 hp 335 hp compared to the original model; on the maximum torque, is 3.2 liters 330 Nm 290 Nm FSI of the original model, 4.2 liter FSI 420 440 Nm of the original model.