Text/Qin Ming
The fuel saving problem of traditional fuel models has always been an important factor for many users to consider when buying a car, so we will talk about the fuel control technology today - fuel injection technology.
carburetor
At present, the fuel injection technology of automobile engine mainly includes single-point electronic injection, multi-point electronic injection, and direct injection in the cylinder. The carburetor is the early fuel atomization into the engine equipment, mainly rely on the engine vacuum to suck the fuel and air into the cylinder, the carburetor mechanism is simple, the failure rate and cost are relatively low, but at low temperatures can not effectively atomize the fuel, the need for in situ heating after the normal use, and the in situ heat car will not only consume more fuel but also cause insufficient combustion and increase emissions, and can not adjust the amount of oil according to the engine conditions, so this injection method has been eliminated for more than ten years, and production is currently prohibited.
With the development of electronic technology, people's requirements for fuel economy are also increasing, and EFI technology has succeeded the carburetor. EFI technology mainly has single point EFI, multi-point EFI and in-cylinder direct injection three technologies, the main principle of electronic injection technology is to increase the sensor in the intake pipe to calculate the intake of the cylinder, in the ECU to calculate the amount of fuel required, so as to control the solenoid valve to inject the corresponding amount of fuel, so that the gas and fuel to achieve the best proportion, and finally let the engine reach the best state.
Single-point EFI
Early EFI technology began with single-point EFI, where the nozzle was placed in the throttle position of the engine's intake manifold, and the fuel was first mixed with the air after the fuel was injected, and then the mixed gas was distributed to each cylinder through the intake manifold.
Because the fuel is first fused with the air and then distributed to each cylinder, the length of the four intake manifolds is different in length, then the total amount of mixed oil and gas entering the cylinder through each manifold will be inconsistent, and the power generated by the deflagration of different cylinders will also be very different, which will lead to unstable engine operation and insufficient combustion of different cylinders.
Multi-point EFI
In order to improve the accuracy of fuel injection, the single electric injection has been improved into multi-point injection, multi-point injection using the injector nozzle is placed in front of the intake door, each intake valve is set up with a nozzle design, the focus is on the length of the intake manifold is also the same, so as to ensure that the amount of air entering each cylinder is the same, so that it can more accurately control the amount of oil injected into the cylinder, improve fuel efficiency, and directly above the valve injection fuel can wash the carbon on the intake valve, bring it into the cylinder to burn, Improve the carbon deposit problem of the intake valve.
Direct injection in the cylinder
Direct injection in the cylinder is more simple and rough than single-point EFI and multi-point EFI, and the injector nozzle is directly installed in the cylinder of the engine, and the fuel is injected into the cylinder, which avoids the attachment of the first two fuels to the intake manifold force and reduces fuel waste.
Because even if the high-pressure injection causes part of the splash on the cylinder wall or piston, it can also be evaporated by high temperature during the compression process, so the direct injection engine can inject oil at a higher pressure, the degree of atomization is higher under high pressure, and the atomized fuel can be evaporated more quickly under high temperature, and the fuel efficiency will be improved after efficient evaporation is realized, that is, the power will be improved to a certain extent.
Moreover, through the position of the injector nozzle and the structural design of the piston fuel chamber, the injected fuel can produce better airflow and mix more fully with the air. Therefore, under the premise of comparable performance, vehicles using direct injection technology in cylinders tend to be more fuel-efficient and have stronger dynamic performance.
Disadvantages of direct injection in the cylinder
At present, the mainstream injection technology is direct injection in the cylinder, but it can not be said that there is no disadvantage in the direct injection in the cylinder, first of all, the valve chamber cover carbon deposition, the second is the fuel injector carbon deposition, because it can not be like multi-point electric injection like the carbon deposit above the valve is washed away, and it is easy to accumulate carbon above the time, but as long as regular maintenance is carried out, it will not affect normal driving. In fact, the carbon deposit problem can also be dealt with, that is, to avoid impurities entering the engine as much as possible, so the more efficient air filter element is also replaced to alleviate the carbon deposit problem.
Another point of direct injection in the cylinder is that the cost is relatively high, and the parts are more demanding than the other two types of electronic spraying. Because the pressure in the cylinder is greater, a high-pressure pump is required to inject the fuel out, but the direct injection in the cylinder has better fuel economy, and the current oil price continues to rise, the fuel costs that may be saved are more expensive than these costs.
In general, the in-cylinder direct injection engine is better than the multi-point EFI engine, but there are still some defects, with the further maturity of the technology, I believe there will be better fuel injection technology to provide users with a better experience.