Engine ignition timing by combustion pressure harmonic phase difference
An ignition timing control for an internal combustion engine is described including a combustion chamber, means effective to ignite a combustible charge in the combustion chamber and power output apparatus including a rotating crankshaft driven in response to the expansion of the ignited combustible charge. The ignition timing control comprises, in combination: pressure sensing mean effective to sense the pressure in the combustion chamber and generate a combustion pressure signal therefrom; means effective to sense the rotational speed of the crankshaft; frequency selective filter means for generating at least two predetermined harmonic signals of the combustion pressure signal, the frequency selective filter means being responsive to the last means to maintain the frequencies of the harmonic signals at whole number multiples of the firing frequency of the engine as the rotational speed of the crankshaft changes; means effective to detect the times of corresponding peaks in the two predetermined harmonic signals and determine the difference therebetween; and means for varying the ignition timing of the engine to reduce the difference to zer in closed loop operation.
- Assignee:
- General Motors Corp., Detroit, MI
- Patent Number(s):
- US 4699105
- OSTI ID:
- 5776981
- Resource Relation:
- Patent File Date: Filed date 17 Nov 1986
- Country of Publication:
- United States
- Language:
- English
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