Causes of high intake manifold pressure

The reason for the high intake manifold pressure is the throttle opening: the smaller the throttle opening, the greater the suction effect formed by the piston during intake, the greater the intake manifold suction and the greater the vacuum degree, that is, the smaller the intake manifold pressure (at this time, the suction of the intake manifold is opposite to its suction).

Second, the engine speed: the higher the engine speed, the greater the suction effect formed by the piston, the greater the suction of the intake manifold and the greater the vacuum degree, that is, the smaller the intake manifold pressure;

The third is sealing performance: including the sealing performance of intake manifold and cylinder. The better the sealing performance, the greater the intake manifold suction and the greater the vacuum, that is, the smaller the intake manifold pressure.

Intake manifold pressure is related to throttle opening, speed and sealing performance, and sealing performance is related to engine wear. Throttle opening and speed are related to the working state of the engine: the smaller the throttle opening, the higher the engine speed and the greater the vacuum suction of the intake manifold. If the throttle opening behind the refueling door increases, the vacuum suction will decrease; However, when the throttle opening increases, the vacuum suction will increase. So what will happen to the vacuum suction of the intake manifold after increasing the throttle? I don't have time to do experiments now, but one thing is clear: if the throttle opening is increased, the engine speed will not be significantly improved due to external resistance, and the vacuum suction of the intake manifold will definitely decrease.

So the conclusion is that when the external resistance is large, the vacuum suction of the intake manifold will decrease, that is, the pressure of the intake manifold will increase. On the contrary, an increase in intake manifold pressure means a larger engine load. (Photo/Text/Photo: Dong Peng) @20 19