EFI University

[Pantera EFI]

When Detonation "bends" a high quality connection rod, their must be an effect on crankshaft speed.

I hope that some agree in the ability to measure this change in acceleration of the crankshaft.

The same engine, same decode (Long 60-2), same day, can exhibit "Pre-Ignition" in testing by tuning/calibrating for damage
to occure on a sparkplug ONLY in one cylinder.

My guess is a measurable change can be "seen" in crankshaft acceleration.

Who has seen this change ?

Lance

[furpo]

I have 'seen' an oscillation in crank shaft speed for a single cylinder engine running with normal combustion. The instrumentation was a scope picking the signal from a hall sensor. The tooth count was 60-1 and was located on the crank. This was a two stroke chainsaw engine running at a fixed speed near 6000rpm with no load. The purpose was to test the accuracy of a hand held tachometer.

It was seen that during combustion the sensor output frequency would increase.

I have no further experience with this sort of testing.

Surely a similar experiment could be conducted to test the validity of the proposed method of knock detection. If an engine was running with no knock and then driven into knock a change in the output signal should be seen if this is a valid method.

You could use both Hall and Variable Reluctance type sensors on the same engine to find which gives the best signal type for this form of knock detection.

If possible I would suggest using a octane rating test engine for this experiment as the experiment would be more repeatable and they are reasonably well set up to determine knock using other methods.

A knock event which bends a rod is major so would be detected by conventional methods.

Roger
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don't mind me, i always need help

[Pantera EFI]

Hi Roger, thank you for your report.
I know that General Motors uses this type of (proposed) method ALONG with their version of 'convential' detection in the 2006+ GM cars.
I know that the elimination of the EGR valve is able to be done because of this, when the Long 60-2 target is fitted to the crankshaft in the GM position.

I know that knowledge of their method is kept "black", a closly guarded secret.

I know that a new Crank Shaft Sensor design was needed for this system to operate within specification.

My guess: This engine design was created to meet this need AND that any other engine may have a different responce.

Would you Roger, all others included, be interested in a team effort to explain this "secret" ?

Lance

[furpo]

What do you propose Lance?

I am not sure what I could bring to such a collaboration that you have not already got.

Have you put a scope on a GM engine which uses this method of knock detection to see the output during a knock event?

You have some knowledge of what GM is doing. Are patents pending which cover this technology?

Roger
_________________
don't mind me, i always need help