The engine is able to work because the combustion of gasoline so that the piston movement work engine to normal operation, the combustion of gasoline in the cylinder is through the nozzle for atomization fuel supply. The way Sensor of fuel injection is also divided into direct injection and EFI.
In-cylinder direct injection technology is a new and now more advanced fuel injection technology. Is to use high pressure directly to the fuel injected into the combustion chamber inside the cylinder. Unlike the original put the nozzle on the front of the intake valve, so that the intake valve is no longer a mixture of oil and gas but pure air. This allows the direct injection engine in the cylinder can be based on the valve to open the time to know the amount of air into the cylinder burning, only in accordance with the time required to work out the corresponding fuel to the amount of fuel. Low fuel consumption, high power, compression ratio of up to 12, with the same displacement of the general engine power Fuel Rail Pressure Sensor and torque are increased by 10%. Direct injection engine High pressure fuel is injected into the combustion chamber, which enters the tiny mist and absorbs heat when it evaporates to cool the cylinder, thereby reducing emissions. But the components are complex, and the price is usually more expensive. Technical requirements are relatively high, in-cylinder direct injection engine technical difficulty is 'stratified combustion' to achieve.
The engine is composed of a number of cylinders, has an orderly work together. So at first people think, in the entrance of the place (intake manifold) fuel injection, each cylinder their own distribution on the line. Its structure is more simple, but by the structure, the working state of the impact, we assigned to the amount of different. Gradually it also withdrew from the market stage. Single-point EFI structure is simple, low cost. But the air-fuel ratio control as multi-point jet engine accuracy, poor emission standards. Automotive engine ejection device is generally by the fuel injection circuit, the sensor group and the electronic control unit composed of three parts. If the injector is installed in the original carburetor position, that is, the entire engine has only one gasoline injection point, which is a single point of ejection; if the injector is installed in the intake pipe of each cylinder, that is, the injection of gasoline is made by multiple places (At least every cylinder has a spray point) sprayed cylinder, which is multi-point EFI. Its structure is simple, the fuel dispenser is not demanding, maintenance Temperature Sensor and reliability of the performance of the oil is not high demand is not high. Although the problem of uneven distribution of single-point EFI mix is improved, it is still not perfect for fuel atomization and oil-gas mixing. Structure is more complex, so the high cost.
Multi-point EFI technology is more mature, cheap, high combustion efficiency, while maintenance more convenient and cheap. Can be used in order to spray, so the air-fuel ratio control more accurate, so the discharge is better, but the degree of fuel-efficient as direct injection technology in the cylinder. In-cylinder direct injection technology is more advanced, in the fuel efficiency, fuel economy, emissions are more than the E-spray to be better. Fuel injection system location is different, it also led to the formation of carbon deposition is different, we all know that gasoline itself is a very good organic solvent, the carbon has a certain cleaning capacity, so the general direct injection engine carbon deposition Concentrated in the back of the intake valve, because the gasoline spray is not, and EFI engine cylinder carbon deposition is more stubborn. Are direct injection within the cylinder, but compared to foreign countries, the engine generated carbon deposition seems to be many times more times. In fact, this and the actual domestic road traffic environment is interrelated. Frequent congestion and low-speed Confucianism with the car, so that the direct injection engine in the fuel mixture temperature significantly increased, theoretically will reduce the combustion efficiency. The reason why foreign direct injection engine in the country less carbon deposition, but also thanks to most of the time, the vehicle at normal speed, direct injection engine in the cylinder combustion efficiency is higher, the probability of spontaneous carbon deposition will be reduced.
Direct injection engines need to cooperate with a lot of other technologies to maximize efficiency, but the introduction of many domestic direct injection engine castration of layered combustion technology, it is certainly not as good as the publicity so good. Because fuel consumption problems are associated with too many factors, gearbox matching, vehicle weight, driving habits, road conditions, etc. will have Speed Sensor a greater impact, direct injection technology represents only the engineers in the fuel injection form of efforts, so we can not simply rough Said that direct injection will be able to save a lot of oil.
Family cars on the election more EFI, multi-point EFI more reliable, low maintenance costs, fuel consumption is not very high. In-cylinder direct injection theory has many advantages, but it is not so good to use, power performance is not perfect, fuel consumption performance is not very good. Of course, the direct injection is the trend, the advantage is irreplaceable. Multi-point EFI also have bottlenecks, and perhaps will eventually be replaced. Faced with increasingly stringent emission regulations, some direct injection engine in the cylinder is difficult to parry. So the R \u0026 D staff remembered manifolds and added them to the direct injection engine to form a hybrid jet system.
Low load conditions, the manifold nozzle in the cylinder intake stroke fuel injection, mixed gas into the cylinder, and then with the compression stroke cylinder fuel injector injections, in order Throttle Position Sensor to achieve stratified combustion; high load conditions, Only in the compression stroke in-cylinder direct injection. In this way, not only can improve the efficiency of the engine, but also to avoid the above mentioned in low load conditions due to excessive oxygen emissions caused by the problem