Engine cycle recognition for fuel delivery
Piston stroke recognition methods for small internal combustion engines, such as single and two cylinder engines, in which the ignition-related trigger pulses corresponding to the engine cylinders are the only input signal used for stroke recognition.
1. In an internal combustion engine including a crankshaft and at least one cylinder having a piston reciprocating therein according to a four-stroke cycle of intake, compression, power, and exhaust, a method for determining the stroke of a piston, comprising the steps of:
generating an ignition-related event for each cylinder during each revolution of the crankshaft;
obtaining an average engine speed;
determining the duration of a plurality of periods between successive ignition-related events, each period corresponding to at least a portion of at least one of an even and odd crankshaft revolution;
obtaining an average duration for the plurality of periods; and
determining the stroke of a piston by comparing the average duration for the plurality of periods to the average engine speed.
2. The method of claim 1 , wherein the ignition-related event is an ignition trigger pulse generated by a magnet passing closely proximate a coil.
3. The method of claim 1 , wherein said first obtaining step comprises:
determining the durations of a plurality of 360° periods between successive ignition-related events of one cylinder; and
obtaining an average engine speed from the durations of the 360° periods.
4. The method of claim 1 , wherein said first determining step and said second obtaining step further comprise:
determining the duration of a plurality of first periods between successive ignition-related events, each first period corresponding to at least a portion of an even crankshaft revolution;
obtaining an average duration for the plurality of first periods;
determining the duration of a plurality of second periods between successive ignition-related events, each second period corresponding to at least a portion of an odd crankshaft revolution; and
obtaining an average duration for the plurality of second periods.
5. The method of claim 4 , wherein said second determining step further comprises:
comparing each of the average durations for the pluralities of the first and second periods to the average engine speed to obtain first and second deviation values, respectively;
comparing the first and second deviation values to one another to obtain a deviation change; and
comparing the deviation change to a threshold value.
6. The method of claim 1 , wherein the engine includes a pair of cylinders arranged X° from one another, and each of the periods in the plurality corresponds to (360°−X°).
7. The method of claim 6 , wherein X° is 90°.
8. In an internal combustion engine including a crankshaft and a pair of cylinders arranged X° from one another, each cylinder including a piston reciprocating therein according to a four-stroke cycle of intake, compression, power, and exhaust, a method for determining the stroke of a piston, comprising the steps of:
generating an ignition-related event for each cylinder during each crankshaft revolution;
obtaining an average engine speed;
determining the duration of at least one (360°−X°) period between successive ignition-related events of the engine cylinders; and
determining the stroke of a piston by comparing the duration of the (360°−X°) period to the average engine speed.
9. The method of claim 8 , wherein said first obtaining step comprises:
determining the durations of a plurality of 360° periods between successive ignition-related events of one of the cylinders; and
obtaining an average engine speed from the durations of the 360° periods.
10. The method of claim 9 , wherein X° is 90°.
11. The method of claim 8 , wherein said first determining step further comprises:
determining the duration of a plurality of first (360°−X°) periods between successive ignition-related events, each first period corresponding to an even crankshaft revolution;
obtaining an average duration for the plurality of first periods;
determining the duration of a plurality of second (360°−X°) periods between successive ignition-related events, each second period corresponding to an odd crankshaft revolution; and
obtaining an average duration for the plurality of second periods.
12. The method of claim 11 , wherein said second determining step further comprises:
comparing each of the average durations for the pluralities of first and second periods to the average engine speed to obtain first and second deviation values, respectively;
comparing the first and second deviation values to one another to obtain a deviation change; and
comparing the deviation change to a threshold value.
13. The method of claim 8 , wherein the ignition-related event is an ignition trigger pulse generated by a magnet passing closely proximate a coil.
14. In an internal combustion engine including a crankshaft and a pair of cylinders arranged substantially X° from one another, each cylinder including a piston reciprocating therein according to a four-stroke cycle of intake, compression, power, and exhaust, a method for determining the stroke of a piston, comprising the steps of:
generating an ignition-related event for each cylinder during each crankshaft rotation;
determining the durations of a plurality of 360° periods between successive ignition-related events of one of the cylinders;
obtaining an average engine speed from the durations of the 360° periods;
determining the durations of even and odd (360°−X°) periods between successive ignition-related events of the engine cylinders;
obtaining average speeds from the durations of the even and odd (360°−X°) periods; and
determining the stroke of a piston by comparing the average speed from the even and odd (360°−X°) periods to the average engine speed.
15. The method of claim 14 , wherein said third determining step further comprises:
comparing each of the averages speeds of the even and odd (360°−X°) periods to the average engine speed to obtain first and second deviation values, respectively;
comparing the first and second deviation values to one another to obtain a deviation change; and
comparing the deviation change to a threshold value.
16. The method of claim 14 , wherein X° is 90°.
17. The method of claim 14 , wherein the ignition-related event is an ignition trigger pulse generated by a magnet passing closely proximate a coil.
18. In an internal combustion engine including a crankshaft and a pair of cylinders arranged at an angle with respect to one another, each cylinder including a piston reciprocating therein according to a four-stroke cycle of intake, compression, power, and exhaust, a method for determining the stroke of a piston, comprising the steps of:
generating an ignition-related event for each of the cylinders during each crankshaft revolution;
determining the durations of a plurality of first periods between successive ignition-related events of one of the engine cylinders corresponding to odd crankshaft revolutions;
obtaining an average duration for the plurality of first periods;
determining the durations of a plurality of second periods between successive ignition-related events of the one engine cylinder corresponding to even crankshaft revolutions;
obtaining an average duration for the plurality of second periods; and
comparing the average duration for the plurality of first periods with the average duration for the plurality of second periods.
19. The method of claim 18 , wherein said comparing step comprises:
obtaining a difference value between the average duration for the plurality of first periods and the average duration for the plurality of second periods periods; and
comparing the difference value to a threshold value.
20. The method of claim 19 , wherein the ignition-related event is an ignition trigger pulse generated by a magnet passing closely proximate a coil.