Many people may have heard of the problem of air leakage in the intake manifold, but if they really encounter this problem, most people may not know how to judge, so let's take a look at the performance of the air intake manifold today.
First, let us define the concept of the intake manifold. If it is a carburetor or throttle body gasoline injection engine, the intake manifold refers to the intake pipe from the carburetor or throttle body to the intake port of the cylinder head. The main function of the pipeline is to distribute the air-fuel mixture to the intake port of each cylinder through the carburetor or throttle body.
For port fuel injection engines or diesel engines, the intake manifold is a pipe that distributes air out.
Since the intake manifold needs to distribute the fuel mixture or clean air to each cylinder as evenly as possible, it is necessary to keep the inner wall as smooth as possible so that the length of the gas passing through the intake manifold is as equal as possible to improve the intake capacity .
The most obvious performance for judging whether the intake manifold is leaking is whether there are phenomena such as high idling speed, acceleration, and easy flameout during acceleration. Even if the situation is serious, it will affect the vehicle.
These are some things that are brought to you today about air intake manifold leaks. If your car often has the above situation, you should consider whether there is a problem with the intake manifold.
Intake manifold refers to the intake pipe from after the carburetor or throttle body to the cylinder head intake port. Its function is to distribute the air and fuel mixture from the carburetor or throttle body to the intake ports of each cylinder.
For a naturally aspirated engine, since the intake manifold is located behind the throttle, when the throttle opening of the engine is small, enough air cannot be drawn in the cylinder, which will cause the manifold vacuum to be high; and when the engine throttle is open When the temperature is large, the vacuum degree in the intake manifold becomes smaller. Therefore, the injection fuel supply engine will install a pressure gauge on the intake manifold to supply the ECU to determine the engine load and give the appropriate amount of fuel injection.
The design of the intake manifold is also very knowledgeable. In order to have the same combustion conditions in each cylinder of the engine, the length and curvature of the manifold of each cylinder should be the same as possible.
Since the engine has four strokes to complete the operation program, each cylinder of the engine will be injected in pulses. According to experience, a longer manifold is suitable for low-speed operation, while a shorter manifold is suitable for high-speed operation.
Therefore, some models will use a variable-length intake manifold, or a continuously variable-length intake manifold, so that the engine can perform better in all speed ranges.
Today’s intake manifold has changed from aluminum to plastic. The main advantages of plastic intake manifolds are lower cost and lighter weight.
In addition, because the thermal conductivity of PA is lower than that of aluminum, the temperature of the fuel nozzle and the incoming air is lower.
Not only can the hot start performance be improved, the power and torque of the engine can be improved, but the heat loss in the pipe can be avoided to a certain extent during the cold start, and the gas temperature can be accelerated. The smooth inner wall of the plastic intake manifold can reduce the air flow resistance, thereby improving the engine Performance. In terms of cost, the material cost of the plastic intake manifold and the aluminum intake manifold are basically the same. The plastic intake manifold is formed at one time, and the qualification rate is high;
The aluminum intake manifold blank casting yield is low, and the machining costs are relatively high. Therefore, the production cost of the plastic intake manifold can be reduced by 20%-35% compared with the aluminum intake manifold.
The master concluded: The intake manifold is an indispensable thing for the engine structure, and most cars nowadays sport a variable intake manifold.