The turbocharged direct injection engine is introduced.

In-cylinder direct injection is also called FSI, and FSI (fuel stratified injection) fuel stratified injection technology represents a development direction of traditional gasoline engines. In the traditional gasoline engine, the cam position of the engine and various related working conditions are collected by the computer, and the injector is controlled to inject gasoline into the intake manifold. However, due to the distance between the nozzle and the combustion chamber, the mixing of gasoline and air is greatly influenced by the intake airflow and the valve switch, and tiny oil particles will be adsorbed on the pipeline wall, so it is hoped that the nozzle can directly inject fuel into the cylinder. FSI is an in-cylinder direct injection technology developed by Volkswagen Group to improve the shortcomings of traditional gasoline engines. The advanced direct injection gasoline engine adopts the fuel supply technology similar to that of diesel engine, and provides the required pressure above 100bar through the piston pump to provide gasoline for the electromagnetic injector located in the cylinder. Then the computer controls the fuel injector to directly inject the fuel into the combustion chamber at the most appropriate time, and the control accuracy is close to millisecond level. The key is to consider the installation of the injector and leave a certain space in the upper part of the cylinder. Because the top of the cylinder has been arranged with a spark plug and a plurality of valves, it is quite compact, so it is arranged near the intake valve. Due to the addition of ejector, the requirements for design and manufacture are quite high. If the layout is unreasonable, the manufacturing accuracy can not meet the requirements, and the stiffness is insufficient or even air leakage can only be lost. In addition, FSI engines require higher fuel quality. At present, the domestic oil consumption situation may be difficult to meet the requirements of FSI engines, so the imported golf of some FSI engines has become acclimatized.

In addition, FSI technology adopts two different fuel injection modes, namely stratified fuel injection mode and uniform fuel injection mode. When the engine is running at low or medium speed, stratified injection mode is adopted. At this time, the throttle valve is in a half-open state, and air enters the cylinder from the intake pipe and collides with the top of the piston. Because the top of the piston is made into a special shape, the expected eddy current is formed near the spark plug. When the compression process draws to a close, a small amount of fuel is ejected by the fuel injector, forming combustible gas. This stratified fuel injection method can fully improve the economy of the engine, because at low speed and light load, only a mixture with high air content needs to be formed around the spark plug, and FSI makes it very close to the ideal state. When the throttle valve is fully open and the engine is running at high speed, a large amount of air enters the cylinder at high speed, forming a strong vortex and mixing evenly with gasoline. So as to promote the full combustion of fuel and improve the power output of the engine. The computer constantly changes the fuel injection mode according to the working condition of the engine, and always maintains the most suitable fuel supply mode. The full utilization of fuel not only improves the fuel utilization efficiency and the output power of the engine, but also improves the emission.

Turbocharged gasoline direct injection engine

TSI gasoline direct injection engine is a technology-leading, energy-saving and environment-friendly engine developed by Volkswagen on the basis of FSI gasoline engine. Compared with the traditional gasoline engine, TSI gasoline direct injection engine has smaller volume, lighter weight and better power output.

technical superiority

The turbocharging system of TSI gasoline direct injection engine can let more air into the cylinder. Gasoline is directly injected into the cylinder through a new high-pressure fuel pump and a 6-hole injector to mix with compressed air, which brings more ideal oil-gas mixing and higher compression ratio, more complete combustion process and stronger power output.

TSI gasoline direct injection engine adopts a new generation of variable cross-section technology, which makes the turbocharger take effect earlier, respond more sensitively and have a wider range of torque output platforms. In addition, because the energy of turbocharger comes from engine exhaust completely, TSI gasoline engine is more efficient than non-supercharged engine and other supercharged engines. While the power performance is obviously improved, its fuel consumption is also greatly reduced, and the vehicle has faster dynamic response and stronger medium-speed acceleration performance. Of course, its advanced design also optimizes the vibration and noise of the engine and greatly improves the comfort of passengers.

The high efficiency power output and low pollution emission of TSI gasoline direct injection engine have brought great development potential for low displacement engines. For example, the 1.4 liter TSI gasoline engine that can be equipped on the sagitar model has a power output comparable to that of the ordinary 2.0 liter gasoline engine, but the fuel consumption is obviously reduced. In a wide engine speed range, this 1.4-liter TSI gasoline engine has excellent power performance, taking into account the torque output at low speed and the power output at high speed. The maximum power output at 5000 rpm can reach 96 kW, and the maximum torque output at 1750 rpm to 3500 rpm can be maintained at 220 Nm.