Abstract: Circuit for controlling the operability of one or more cylinders of a multicylinder internal combustion engine having electrically controllable means associated with it for preventing combustion from occurring in at least one cylinder of the engine. Preferably, the electrically controllable means for preventing combustion in a cylinder comprises a solenoid and associated mechanical means for preventing opening of the intake and exhaust valves for such cylinder to be thus disabled. Maintaining the intake and exhaust valves in a closed condition prevents the intake of an air-fuel mixture and permits compression and expansion, in a spring-like manner, of gases trapped within the combustion chamber.

Abstract: Circuit for controlling the operability of one or more cylinders of a multicylinder internal combustion engine having electrically controllable means associated with it for preventing combustion from occurring in at least one cylinder of the engine. Preferably, the electrically controllable means for preventing combustion in a cylinder comprises a solenoid and associated mechanical means for preventing opening of the intake and exhaust valves for such cylinder to be thus disabled. Maintaining the intake and exhaust valves in a closed condition prevents the intake of an air-fuel mixture and permits compression and expansion, in a spring-like manner, of gases trapped within the combustion chamber.

Abstract: A frequency responsive switching circuit that, in the preferred form, includes circuit means for generating a periodic first electrical signal. The first electrical signal is applied to a retriggerable monostable multivibrator having as its output a second electrical signal. A timing circuit associated with the retriggerable monostable multivibrator controls the duration of the output pulses constituting the second electrical signal. If the period of the first electrical signal is less than a predetermined amount, the second electrical signal is maintained at a fixed voltage level due to continuous retriggering of the multivibrator. The second electrical signal is applied to the data input of a shift register and the first electrical signal is supplied to the shift register as a trigger input. Multiple bit outputs of the shift register form the inputs to a gate circuit.