Abstract: The improved battery-powered lawnmower includes a safety key that is automatically removed when the removable battery is removed, while at the same time blocking the battery recharger receptacle. The lawnmower also includes a control circuit that shuts off the lawnmower upon the occurrence of one or more of several predetermined conditions, including low battery voltage, the encountering of heavy grass for a period of 3 seconds or more, and high motor current that may occur when the cutting blade is jammed. The cutting blade is designed to move through any debris accumulated between the blade ends and the housing sidewall without sacrificing the lift for needed cutting and mulching. The invention also includes a unique height adjustment assembly for adjusting the height of the chassis, a handle attachment that allows the handle to be positively tightened to the lawnmower chassis, and a telescoping groove for the battery's quick connect/disconnect terminals.

Abstract: The improved battery-powered lawnmower includes a safety key that is automatically removed when the removable battery is removed, while at the same time blocking the battery recharger receptacle. The lawnmower also includes a control circuit that shuts off the lawnmower upon the occurrence of one or more of several predetermined conditions, including low battery voltage, the encountering of heavy grass for a period of 3 seconds or more, and high motor current that may occur when the cutting blade is jammed. The cutting blade is designed to move through any debris accumulated between the blade ends and the housing sidewall without sacrificing the lift for needed cutting and mulching. The invention also includes a unique height adjustment assembly for adjusting the height of the chassis, a handle attachment that allows the handle to be positively tightened to the lawnmower chassis, and a telescoping groove for the battery's quick connect/disconnect terminals.

Abstract: The device automatically determines whether a load is being applied to the engine, and outputs a change signal that is used to change one or more engine operating parameters accordingly, such as engine speed, engine timing, or fuel flow. The load is sensed without using a manifold pressure or throttle plate position sensor, thereby reducing the cost of the system. The load is sensed by determining a period of a first crankshaft revolution, determining a period of the successive second crankshaft revolution, and computing a difference value that is a function of the difference between the first and second periods. Since the difference value is proportional to engine load, the difference values may be compared with a reference value to determine whether a load is being applied to the engine. The reference value may be preset, may be manually determined by the operator, or may be learned by the system's software.

Abstract: A microprocessor-controlled inductive ignition system uses a magneto inductive ignition circuit at engine starting speeds, and a microprocessor-controlled ignition circuit at engine running speeds. The microprocessor senses the ignition firings, computes the time between successive ignition firings, and disables the magneto inductive ignition system when the engine speed is greater than a predetermined cut-off speed. The ignition system enables an engine with a recoil starter to be started if the battery is low or if an alternator is used to power the microprocessor. At engine running speeds, the ignition system achieves a greater amount of timing advance than achievable with an inductive ignition system alone, thereby increasing engine efficiency.

Abstract: The modular, automatic idle down system is plugged in series between the 120 VAC output connector of a generator and the input plug of the load device. One prong of the load's input plug may be received directly in a load sensor, such as a Hall effect sensor. The self-contained modular unit is connectable to the mechanical or electronic governor of the generator's engine. The idling system provides two time delays which delay the idling down of the engine upon initial starting and when the load is removed from the generator. When the sensed load current falls below a threshold value, the idling system generates an output signal, after the predetermined time delays, to override the engine's mechanical or electronic governor. The speed-of the engine is thereby reduced from the governed speed to an idle speed.

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: The starting system allows small engines having electronic governors to be powered by an alternator, thereby eliminating the need for a battery or a manually-operated start lever. The starting system causes the throttle to be in the Wide Open Throttle position at engine starting speeds. The starting system disengages at engine running speeds above about 1200 RPM. The starting system includes a pivotable lever arm, a spring that biases the lever arm in a first direction, and a centrifugally-responsive flyweight assembly that moves the lever arm in the opposite direction. At engine starting speeds, the spring force is greater than the opposing force applied by the flyweight assembly, causing the lever arm to engage a governor arm and to open the throttle to the Wide Open Throttle position. At engine running speeds, the opposing force increases and overcomes the spring force.

Abstract: The safety interlock prevents the starting of a device if one or more safety switches is not first cycled through its operational cycle. Since the safety switches must be operated before starting, the device will not operate if the switches have been tampered with or have failed. The interlock includes a digital memory unit connected to the switch which stores information indicative of the cycling of the switch. The output of the memory unit is interconnected with the starting system of the device such that starting is prevented unless the stored information indicates that each switch has been cycled. In a preferrred embodiment the interlock includes a microprocessor.

Abstract: The idling system reduces the speed of an engine having a speed governor that is used to power an air compressor, a pressure washer, or another load device which outputs pressurized gases or fluids. The idling system includes a pressure or flow switch which is activated in response to a sensed pressure or fluid flow respectively in the load device. When the switch is activated, an electromagnet is energized through a diode rectifier by the engine alternator or other power source. The energizing of the electromagnet creates a magnetic field that attracts a governor lever arm on the engine's mechanical speed governor. Since the lever arm is interconnected with the throttle plate of the engine carburetor, movement of the lever arm rotates the throttle plate to reduce the engine speed to an idle speed.

Abstract: The microprocessor-based speed limiter compares a speed value functionally related to the actual speed of the engine with a stored reference value and generates a limit signal to ground the ignition pulses if the speed value is greater than or equal to the reference value. The ignition pulses are preferably grounded for a preselected number of engine revolutions, after which another comparison is made to determine whether the actual engine speed is below the maximum limit speed. Both the stored reference value and the preselected number of engine revolutions may be changed.

Abstract: An idling system is disclosed for devices such as internal combustion engines having a speed controlling or governor. When no load is sensed by a load sensing means, a disable means generates a disable signal to deactivate the engine's speed controller after a predetermined time delay period. When a load is sensed, the disable means is itself disabled, allowing the device's speed control means to operate the device at the higher governed speed.

Abstract: An engine speed limiter includes a computing means for computing a value that is functionally related to the time between successive ignition pulses and for outputting a speed signal representative thereof. The speed limiter also includes generating means for generating a reference signal that is functionally related to the desired maximum limit speed. A comparison means compares the speed signal with the reference signal and generates a limit signal if the result of the comparison indicates that the actual engine speed is about equal to or greater than the desired maximum limit speed. The limit signal is used to interrupt engine ignition to thereby limit engine speed.