Timing control system for internal combustion engines

Abstract From the Canadian patent

An ignition timing control system for an internal combustion engine has a first vacuum passage connected to the engine intake passage downstream from the throttle valve and a second throttled vacuum passage connected to the engine intake passage slightly upstream from the throttle valve in closed position, both vacuum passages being connected to the angle advance chamber of the ignition timing device of the engine. A solenoid valve is placed in the first vacuum passage and a delay valve is placed in the second vacuum passage. An electrical circuit for energizing the solenoid valve includes an electrical switch which closes when the engine temperature is low so that the ignition, timing of …