What is the normal intake pressure of a six-cylinder diesel engine?

The cylinder pressure of gasoline engine is generally 8~ 1 1bar, and that of diesel engine is generally 12~ 16bar, subject to the reference manual. 1. Throttle opening: The smaller the throttle opening, the greater the suction effect formed by the piston during intake, and the greater the vacuum suction of the intake manifold, that is, the lower the intake manifold force.

2. Engine speed: The higher the engine speed, the greater the suction force formed by the piston during air intake, and the greater the vacuum suction force of the intake manifold, that is, the lower the intake manifold force.

3. Sealing performance: including the sealing of intake manifold and cylinder. The better the sealing performance, the greater the suction force formed by the piston during intake, and the greater the vacuum suction force of the intake manifold, that is, the lower the intake manifold force.

There is a fixed range and law for the vacuum degree of the intake manifold of the normal engine:

On the other hand, if the vacuum degree deviates from the normal value, the engine must be faulty. This is a common cause of abnormal vacuum reading, such as one or more spark plugs not firing, damaged air hose or loose hose connector, and poor valve seal.

The cylinder head potential or intake manifold gasket leaks, the piston ring leaks seriously, the exhaust gas recirculation valve (EGR) cannot be closed, and the positive crankcase ventilation valve (PCV) is stuck in the fully open position. Different reasons correspond to different readings of vacuum gauge. It is helpful for fault diagnosis to master the correct readings of vacuum gauge under common working conditions and some abnormal situations caused by faults.