In at least some implementations, a method of maintaining an engine speed below a first threshold, includes: (a) determining an engine speed; (b) comparing the engine speed to a second threshold that is less than the first threshold; (c) allowing an engine ignition event to occur during a subsequent engine cycle if the engine speed is less than the second threshold; and (d) skipping at least one subsequent engine ignition event if the engine speed is greater than the second threshold. In at least some implementations, the second threshold is less than the first threshold by a maximum acceleration of the engine after one ignition event so that an ignition event when the engine speed is less than the second threshold does not cause the engine speed to increase above the first threshold.

A barrier-discharge-type ignition apparatus that can accurately determine the application voltage, of a barrier ignition plug, that causes a non-ignition discharge to occur. In the barrier-discharge-type ignition apparatus, in a combustion assist control, the voltage difference between the one-period-prior application voltage and the present-period application voltage in the AC period is calculated based on an application voltage detected by a voltage detection circuit; then, it is determined whether or not a discharge exists in the barrier ignition plug, based on the comparison between the voltage difference and a preliminarily set discharge determination threshold value.

In general, the subject matter described in this disclosure can be embodied in methods, systems, and program products for performing vehicle control. A computing system determines a difference between a recent rate of change and a historical rate of change of a rotating vehicle shaft of a vehicle during a vehicle race. The computing system determines that the difference between the recent rate of change of the rotating vehicle shaft and the historical rate of change of the rotating vehicle shaft satisfies a criteria for limiting vehicle power, wherein the computing system changes the criteria for limiting vehicle power during the vehicle race. The computing system sends a signal for receipt by a vehicle component of the vehicle, to cause the vehicle component to limit rotation of the rotating vehicle shaft.

The invention relates to an improved ignition system for spark ignited combustion engines. According to the invention the voltage over a coil winding 6P on the primary side of the ignition coil is regulated to a sufficiently low voltage level during timed periods of the ignition cycle, such that at least one function out of three in total, i.e. prevention of premature spark-on-make, or spark suppression after onset of ignition, or improved frequency response between primary and secondary side of the ignition coil after end of ignition, is obtained. When applied in an inductive ignition system a differential amplifier (8) may be connected over the primary winding 6P regulating a control switch 2CS via a drive unit (9). The invention is preferably implemented in ignition systems with ion sense circuitry 5C,5R on the secondary side of the ignition coil, and implementing all three functions.

In general, the subject matter described in this disclosure can be embodied in methods, systems, and program products for performing vehicle control. Multiple target rotation rates for a vehicle shaft may be identified. A first actual rotation rate may be determined to exceed a first target rotation rate. In response, a computing system may send a first signal in order to cause a first component of a vehicle to limit the rate of rotation of the vehicle shaft. A second actual rotation rate may be determined to be below a second target rotation rate. In response, the computing system may send a second signal in order to cause the first component of the vehicle or a second component of the vehicle to increase the rate of rotation of the vehicle shaft.

There is provided an engine rotation speed control device for performing over-speed rotation prevention control to decrease an engine rotation speed if the engine rotation speed exceeds a first upper limit rotation speed. If a gear position of a transmission is a neutral state or an intermediate neutral state in which predetermined gears are not engaged with each other in the middle of a gear change operation of the transmission, a second upper limit rotation speed which is lower than the first upper limit rotation speed is set. If the engine rotation speed at the time when the gear position of the transmission is the neutral state or the intermediate neutral state is higher than the second upper limit rotation speed, the over-speed rotation prevention control is performed.

An electronic governor system includes a motor, a transmission coupled to the motor, a throttle plate coupled to the transmission, the throttle plate movable to multiple positions between closed and wide-open, wherein power is supplied to the motor to move the throttle pate to a desired position and wherein power is not supplied to the motor to maintain the throttle plate in the desired position.

A method is for the safe starting of a combustion engine in a handheld, portable work apparatus. When starting, start rpm limiting is activated when the rotational speed of the combustion engine exceeds an activation rotational speed that lies above the coupling rotational speed of a centrifugal coupling. After activating the start rpm limiting for at least one working cycle, an intervention in the ignition is carried out such that the rotational speed of the combustion engine decreases. After the rotational speed has decreased below a lower engagement rotational speed, an intervention in the ignition is carried out such that the rotational speed increases. If the rotational speed exceeds an upper engagement rotational speed, an intervention in the ignition is again carried out such that the rotational speed decreases. The upper engagement rotational speed and/or the lower engagement rotational speed is/are changed with an increasing number of consecutive working cycles.

An engine-driven working machine according to the present invention has a controller and a muffler. The controller is operated from starting of the engine in a rotational speed limitation mode in which the engine is prevented from rotating at a rotational speed that is higher than the predetermined limitation rotational speed. The controller forces to stop the engine, after a predetermined period has passed, during which the engine operates in the rotational speed limitation mode.

A method for controlling the operation of a spark ignition internal combustion engine is described. The engine includes: a combustion chamber, an intake duct for placing the combustion chamber in communication with the external, a throttle valve arranged inside the intake duct, a carburetor for introducing fuel into the intake duct to form an air/fuel mixture to be intaken into the combustion chamber, and a spark plug arranged inside the combustion chamber to generate a spark for igniting the combustion of the air/fuel mixture. The method includes: monitoring the opening degree of the throttle valve; monitoring the speed of the engine, preventing the spark plug from generating the spark, if the opening degree of the throttle valve drops below a first opening degree threshold value and the speed of the engine is greater than a first engine speed threshold value.