Explain the modification principle of four-throat direct injection engine.

Firstly, the intake system of automobile engine is explained. The intake manifold contains a throttle that controls the intake air volume. According to the different configuration of throttle, it can be divided into "single-throat type" which supplies air to each cylinder evenly behind the throttle and "multi-throat type" which uses a single throttle for each cylinder independently, also known as multi-throat direct injection system. Considering the convenience of maintenance and cost control, the general commercial mass production vehicles usually adopt a single throat throttle with the least number of parts. The so-called high-performance sports car, in order to pursue high-peak horsepower and instantaneous/post-acceleration, can directly delete the cost and price factors and directly use the multi-throat direct injection system under the principle of reciprocity. The advantage of multi-throat system is not only to increase the effective area of the throttle, but also to make the manifold reach the theoretical requirements of short distance, equal length and good straightness because of its structure without throttle cavity, thus interfering with the change of intake horn or valve and ensuring that each cylinder can obtain a large number of rapid intake efficiency. In the early years, almost all love express trains were multi-throat. Recently, Japanese AE/KOOC-0/0/KOOC-0//KOOC-0//KOOC-0/,BMW M3, 9/KOOC-0//RSR, Ferrari trains are all multi-throat direct injection systems, so it can be seen that the NA car has been obtained. Even if the turbo car wants to show more violence, it can still rely on the multi-throat system. The overall performance of multi-throat system is mostly concentrated in the middle and high speed field. The shorter the manifold, the better the efficiency of air entering the cylinder and the greater the high-speed horsepower output. However, the longer manifold can improve the torque at middle and low speeds, which is beneficial to ordinary urban streets. The above are just the general characteristics of multi-throat direct injection. If the fuel consumption, torque and horsepower change under the condition of fixed-mode multi-throat manifold, the throttle valve diameter must be selected. Generally, there are 40mm, 45mm and 50mm throttles. When using the 50mm throttle engine, the displacement is better than 2000 c c, and the compression is better controlled above 12: 1. Moreover, due to the large caliber, the amount of gas inhaled at the moment of acceleration is too large, which is not comparable to most computers. It needs to be programmed if necessary. Generally, the air inlet with multi-throat direct injection design is usually equipped with only one horn for performance, but the hot air generated in the engine room will relatively affect the quality and density of the air inlet, so it is best to install a large pressure accumulation gas collector, which can increase the instantaneous acceleration force and make the engine have better high torque performance. The specifications and dimensions of the multi-throat system designed by the original factory are absolutely different from one family to another, but when it is used in the standard modification kit, the multi-throat system has its own specifications. Generally speaking, the side suction system is called "DCOE" and the down suction system is called "DCNF". These two specifications must be clear, because when ordering a modified multi-throat kit, 20% and 20% will always be paired, that is, the four throats are two groups of valve bodies and the six throats are three groups of valve bodies (the only special system is the 9 1 1 system, in which the multi-throat system is left and right, and each group has three throttle valves, which is different from other modified systems). Like the valve body, how to deal with different engines depends on the intake manifold, and different intake manifolds can match different types of engines. Therefore, a multi-throat direct injection system consists of intake manifold, two or three or four groups of valve bodies, bell mouth, fuel rail, fuel nozzle, throttle valve and pipeline bracket group. In recent years, in order to make the function of multi-throat direct injection more powerful, manufacturers have also developed a throttle valve different from the previous butterfly valve and adopted a slide valve type. The biggest difference between the two systems is that the butterfly valve XX has a rotating shaft fixed valve, and there are still obstacles when it is fully opened, which hinders the flow of air, of course, there will be substantial loss of horsepower; When the throttle valve of the side plate is fully opened, the throttle valve completely becomes a hole with no parts inside, and the side plate is actually hidden in the space next to the valve body. Although the multi-throat system has many advantages, the more parts, the more complex the structure, the more difficult it is to set up, which is not possible for ordinary manufacturers, and its setting and adjustment are equally important. Assuming that the project is not handled perfectly, the result is very bad idle speed and uncoordinated jitter acceleration. The multi-throat linkage device connected by a valve body with two throats basically regulates the air intake of each cylinder, and its idle speed regulation needs to connect each cylinder manifold with a vacuum gauge group and adjust the bypass valve to make the idle air intake of each cylinder consistent; Don't think that the throttle is adjusted to the same opening (in fact, this adjustment project is a bit complicated)! Next, test whether the intake flow of each cylinder is equal when the throttle valve is opened with a multi-throat special flowmeter, and adjust the throttle valve opening screw to make it consistent. After oil return, it is necessary to adjust the bypass screw again to determine whether the idle speed is balanced. A multi-throat system with unbalanced adjustment will lead to unsmooth engine and poor horsepower output, but it will lead to serious imbalance of each cylinder and abnormal engine wear, which must not be taken lightly! Generally, the so-called four-throat products are all derived from the concept of multi-throat, which also shortens the four-pronged part and increases the internal caliber to the same length as much as possible. Combined with the type of bell mouth and smooth inner wall, the single throttle manifold also has the advantages of multi-throat manifold, which greatly improves the intake efficiency! Especially high speed and acceleration are decisive. Other strengthening methods include increasing the throttle valve and then increasing the manifold to match the intake with the throttle valve, which can also increase the pressure storage efficiency. Finally, I want to emphasize to you that you should pay attention to the adjustment of mixing ratio after the manifold and throttle are maximized. No matter how much air intake there is, if there is no proper amount of oil supply to match it, the engine still cannot play its due perfect performance!