Automatic vacuum advance controller for ignition system - uses two vacuum units acting independently on rotatable plate in ignition distributor to produce more complex advance curves

摘要

The vacuum advance controller has two independent vacuum displacement units which may be arranged to act successively or together to give various vacuum advance characteristics. The vacuum advance units are coupled to the rotatable plate in the rotating magnet type ignition distributor. Each vacuum unit (1,2) has a single arm (3,4) which moves directly in or out of the unit depending on the level of engine vacuum. At the end of each arm an elongated hole (7,8) fits over a pin (5,6) attached to the rotatable plate (10). One of the arms (3) is curved around so it clears the rotor shaft but is close to a third pin (11) on the plate (10), which acts as a motion stop for the plate rotation generated by the other vacuum unit arm (4). The two vacuum units may have different characteristics, one controlling low vacuum advance, the other controlling medium vacuum advance and, at high vacuum, both units combining to produce further ignition advance.