Claims
- 1. A method for timing a Harley Davidson type engine having a timing port through which a timing mark indicative of a position of a movable member of the engine can be seen, the method comprising:securing a variable reluctance sensor proximate the timing port of the Harley Davidson type engine; sensing the presence of the timing mark of the engine with the variable reluctance sensor and providing a timing mark signal as a function thereof; sensing an occurrence of an ignition spark and providing an ignition signal as a function thereof; filtering ignition sparks of compression strokes from ignition sparks of compression and exhaust strokes of a selected cylinder and providing a filtered ignition signal being indicative of only the ignition sparks of compression strokes; generating a delayed signal having a selected delay from the filtered ignition signal; comparing the timing mark signal to the delayed signal and providing an output signal indicative of substantial simultaneous occurrence of the timing mark signal and the delayed signal; and operating an indicator as a function of the output signal.
- 2. The method of claim 1, wherein filtering comprises comparing the ignition signal with a selected threshold.
- 3. The method of claim 1 wherein filtering comprises:detecting a peak amplitude of the ignition signal; and forming the selected threshold as a function of the ignition signal from at least one previous spark.
- 4. A combination comprising:a Harley Davidson type engine having a timing port and a timing mark indicative of a position of a movable member, wherein the Harley Davidson type engine provides ignition sparks for compression strokes and exhaust strokes to a selected cylinder; an ignition timing device including: a variable reluctance sensor secured in the timing port to provide a timing mark signal indicative of presence of the timing mark; an ignition sensor adapted to provide an ignition signal indicative of the occurrence of an ignition spark; a filter receiving the ignition signal and to provide a filtered ignition signal, the filter filtering ignition sparks of compression strokes from ignition sparks of compression and exhaust strokes of the selected cylinder; a delay element receiving the filtered ignition a selected delay from the filtered ignition signal; a comparator receiving the timing mark signal and the delayed signal, the comparator providing an output signal indicative of substantial simultaneous occurrence of the timing mark signal and the delayed signal; and an indicator receiving the output signal and operable as a function thereof.
- 5. The combination of claim 4 wherein the variable reluctance sensor comprises;a support tube insertable in the port and having a bore extending from a first end to a second end; a sensor housing insertable in the bore; and a variable reluctance probe disposed in the sensor housing.
- 6. The combination of claim 5 wherein the support tube includes exterior threads adapted to mate with threads of the port.
- 7. The combination of claim 6 wherein the support tube includes interior threads and the sensor housing includes exterior threads adapted to mate with the interior threads.
- 8. The combination of claim 1 wherein the filter includes a comparator, wherein the filtered ignition signal is indicative of a spark exceeding a selected threshold.
- 9. The combination of claim 8 wherein the selected threshold is constant.
- 10. The combination of claim 8 and further comprising a peak detector, and wherein the selected threshold is a function of at least one previous detected spark.
- 11. The combination of claim 4 wherein the ignition sensor comprises a light detector.
CROSS-REFERENCE TO RELATED APPLICATION
This application claims priority of U.S. patent application Ser. No. 60/103,026, filed Oct. 5, 1998, and Ser. No. 60/144,750, filed Jul. 21, 1999, both of which are herein incorporated by reference in their entirety.
US Referenced Citations (24)
Non-Patent Literature Citations (1)
Entry |
Haynes Automotive Repair Manual #867 for a Pontiac Firebird 1982 thru 1992, pp. 55-56. Copyright 1993. |
Provisional Applications (2)
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Number |
Date |
Country |
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60/103026 |
Oct 1998 |
US |
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60/144750 |
Jul 1999 |
US |