An internal combustion engine employing a valve regulating the passage of a fluid between the hollow interior of the combustion chamber and the atmosphere. The valve includes a valve body having a valve opening and a blade track passing around the valve opening. A guillotine blade slides linearly along the blade track between an open position in which said fluid may pass through the valve opening and a closed position in which the fluid is restricted from passing through the valve opening. A reciprocating driver moves the guillotine blade along the blade track when actuated by an electronic control signal.