Posted 26 March 2012 - 09:54
Posted 26 March 2012 - 14:05
Some sort of balance or frequency test?
Posted 26 March 2012 - 22:03
Posted 26 March 2012 - 22:37
Posted 26 March 2012 - 23:14
I am fascinated. Can someone post photos or a diagram? I assume the cup is in the control room - how is that done?
Take a long piece of that flexible copper brake tube. poke it through the wall of the test cell. point the open end at the engine, say 6 inches from the cylinder head.
Buy a cup of something that almost but not quite bears no resemblance to tea from a machine. Throw the contents away. Spike the cup onto the control room end of the pipe. listen to the noise.
Calibrating knock (det) sensors is tricky, they are bandpassed, high frequency accelerometers and cost about 23c each so they aren't exactly high quality. As engine speed inceases they respond to the various clatters and bangs as well as knock, so the trick is to choose the right location for the sensor, the right bandpass characteristic, and the right threshhold vs rpm (there is quite a bit more to this). Your ear suffers from none of these deficiencies. However, there is inaudible det, which can kill engines as well.
Posted 27 March 2012 - 00:33