hi,

can u tell me which kind of sensors used to detect the leakage from the inlet and exhaust valve of the engine cylinder?

 

1) bourdon tube pressure gauge on a flexible hose with a spark plug fitting adapter on the end.

2) In 1976, VW used a clamp-on current sensor on the power cable from the battery to the starter solenoid to measure starter motor current draw on their Wolfsburg factory service department analysis computer.

I can't recall where the synch signal came from (to indicate cylinder ID) , but a paper tape printout provided a relative comparison of compression between cylinders, a bar graph, if I recall properly (and 30 years later, I could be mistaken on the format of the printout).

3) PLC forums occasionally have comments relating to the use of pressure sensors for leak rate detection for reciprocating engine combustion chambers. Given the nature of the ideal gas law, I'm not sure how well that spins out, when temperature sensing and correction becomes a factor.

Dan

 

Usually just a pressure guage. Pressurize and shut off the air. Observe the rate of decrease. This is called a leakdown test. You could use ultrasonics in the manifolds but that is pretty much pass/fail, hard to quantify. It would have the advantage of being insensitive to ring leakage.

Regards
cww