Abstract: The engine governor outputs a pulse width modulated actuator control signal at two or more frequencies to improve actuator performance. In one embodiment, the control signal has a frequency of about 60 to 70 hertz when the throttle is nearly closed, and switches to a frequency of between 5 to 30 hertz once the throttle is between 50 to 75 percent open. In a second embodiment, the frequency of the actuator control signal decreases in a linear manner from 60 to 70 hertz to between 5 to 30 hertz as the throttle is opened from a closed throttle position to wide open throttle. A decrease in frequency with increased throttle opening provides additional control signal off time, thereby allowing the magnetic field in the actuator to sufficiently dissipate for proper dithering action.

Abstract: The electronic governor has a fast response time by eliminating the return spring of prior art governors. Instead, a magnetic field generated either by permanent magnets or by a second actuator coil is used to oppose the force created by a first actuator coil. The current to the first actuator coil is pulse width modulated. If a second coil is used instead of permanent magnets, the current to the second coil may be either pulse width modulated or may be a constant DC signal. An actuator having a low inertia rotor and a stationary core is preferred to further reduce the response time.

Abstract: An ignition-powered engine shut-off circuit is provided for power-driven apparatus such as lawn mowers, pumps, generators, tractors and the like. The shut-off circuit preferably includes a first switch, such as a low oil or toggle switch, which is activated when a particular condition exists. The circuit also includes an electronic switch that is subject to the control of a switch control means. When the first switch senses that a particular condition exists, the switch control means gates on the electronic switch, grounding the ignition pulses and shutting off the engine. The first switch is preferably a reed switch used to sense low oil levels, and the electronic switch is preferably a high-power SCR or other thyristor. An indicator means consisting of an LED and a shunt resistor indicates that the ignition pulses are being grounded.