Engine operation detecting circuit for a visual display

Details Engine operation detecting circuit for a visual display Engine operation detecting circuit for a visual display

2000-09-07

2002-04-23

Lefkowitz, Edward (Department: 2632)

Communications: electrical

Land vehicle alarms or indicators

Internal alarm or indicator responsive to a condition of the...

C340S648000, C123S429000

Reexamination Certificate

active

06377168

ABSTRACT:

FIELD OF THE INVENTION
The invention relates to a visual display circuit for monitoring and displaying the operation of a combustion engine and more particularly concerns an circuit for monitoring the operation time of a riding lawn mower.
BACKGROUND ART
Hour meters of various types are commercially available both as an add on device to a combustion engine or supplied as part of a vehicle that has a combustion engine. The hour meter provides information about the amount of time the engine has been operating. This information is useful for scheduling maintenance necessary at predetermined engine run times. In addition, hour meters may be used on test vehicles to calculate the durability of engine components as a function of engine run time.
U.S. Pat. No. 5,644,491 to Fiske et al. concerns a self contained multi-function engine monitor and timer for providing engine running time, job time, service time and tachometer functions. The engine monitor employs a spark sensor in the form of a pick up wire wrapped around a spark plug wire. The spark plug current flowing through the spark plug wire induces a voltage across the coil of the pick up wire. This voltage is sensed by a microcomputer and is used to determine a variety of engine functions. Circuitry is required to filter the signal from the pick up wire to make it suitable for input to the microcomputer.
U.S. Pat. No. 4,617,639 to Paine concerns an hour meter apparatus and method for use with industrial vehicles. The hour meter increments time interval registers whenever the ignition switch of the vehicle is in a position indicating that the vehicle is in operation. Because the hour meter is activated by the ignition switch of the vehicle, engine time may be logged when the ignition switch is turned to the on position, but the vehicle's engine is not running.
SUMMARY OF THE INVENTION
The present invention concerns a timing circuit for providing an output to a monitoring circuit indicating whether an engine having a magneto is operating. In a preferred embodiment, the monitoring circuit is a microcontroller. The timing circuit includes switching means, such as a triac in an exemplary embodiment, coupled to the magneto for switching output generating circuitry between an engine on condition and an engine off condition in response to an operating condition of the engine. The output generating circuitry provides a signal indicating that the engine is not operating to the microcontroller when the circuitry is in an engine off condition and provides a signal indicating that the engine is operating to the microcontroller when the circuitry is in an engine on condition.
In an exemplary embodiment, the triac is activated by pulses generated by the magneto when the engine is operating to place the output generating circuitry in the engine on condition. The triac operates in a conducting mode and the circuitry includes a capacitor that discharges to ground through the triac thereby maintaining the output circuitry in the engine on condition. The triac is deactivated when the magneto is not generating pulses to place the output generating circuitry in the engine off condition such that the triac does not conduct current. The circuitry includes a transistor that switches on when the triac is not conducting current to maintain the output circuitry in the engine off condition.
In an embodiment of the present invention, the microcontroller senses a voltage at the capacitor and records a time between drops in said voltage to determine the RPM of the engine.


REFERENCES:
patent: 3992070 (1976-11-01), Dunn et al.
patent: 4129037 (1978-12-01), Toalson
patent: 4144862 (1979-03-01), Estkowski
patent: 4181883 (1980-01-01), Beeghly et al.
patent: 4187927 (1980-02-01), Byrne
patent: 4280457 (1981-07-01), Bloxham
patent: 4613939 (1986-09-01), Paine
patent: 4617639 (1986-10-01), Paine
patent: 4642787 (1987-02-01), McCarthy et al.
patent: 4742297 (1988-05-01), Heaton et al.
patent: 5065320 (1991-11-01), Hayashi et al.
patent: 5138995 (1992-08-01), Erhard
patent: 5150568 (1992-09-01), White
patent: 5375977 (1994-12-01), Hill
patent: 5642284 (1997-06-01), Parupalli et al.
patent: 5644491 (1997-07-01), Fiske et al.
patent: 5730098 (1998-03-01), Sasaki et al.
patent: 5857159 (1999-01-01), Dickrell et al.
patent: 5869776 (1999-02-01), Vuong et al.
patent: 5913911 (1999-06-01), Beck et al.

Affiliated with

Also associated with

Rating

Engine operation detecting circuit for a visual display does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Engine operation detecting circuit for a visual display, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Engine operation detecting circuit for a visual display will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2920000