Ignition timing adjusting device for internal combustion engines
AssigneesAisin Seiki Kabushiki Kaisha, Toyota Jidosha Kogyo Kabushiki Kaisha
InventorsMasami Inada, Yasuhiro Kawabata, Katsujiro Sato, Akinori Osanai
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Abstract
In an ignition timing adjusting device, a breaker plate of a distributor is held in the initial position thereof during idling of the engine and the breaker plate is temporarily moved in the retarding direction in a period of time after starts of the vehicle to positively retard the ignition timing of the engine so as to minimize the NOx emission and thereafter, instantly moved in the advancing direction upon arrival at a cruising speed of the vehicle to quickly advance the ignition timing of the engine so as to ensure good driveability of the vehicle.
Claims8
An ignition timing adjusting mechanism in combination with an internal combustion engine having a carburetor with a throttle valve and a distributor with a breaker plate for the engine, comprising:
- a vacuum actuator provided therein including a diaphragm piston forming first and second servo-chambers in said actuator and operatively connected to said breaker plate of said distributor, said diaphragm piston being moved in one direction from an original position to move said breaker plate in a retarding direction and being moved in the other direction to move the breaker plate in an advancing direction;
- a change-over valve means interposed between said vacuum actuator and said throttle valve of said carburetor for selectively connecting said first and second servo-chambers to atmospheric air and a negative pressure port upstream of said throttle valve therethrough, said valve means being changed-over from a first position, in which said first and second servo-chambers are respectively connected to the atmospheric air and said negative pressure port to move said diaphragm piston in one direction, to second position in which said first and second servo-chambers are respectively connected to said negative pressure port and the atmospheric air to move said diaphragm piston in the other direction;
- and
- means for delaying the switchover timing of said valve means to provide a predetermined time lag after occurrence of negative pressure at the throttle valve;
- whereby when the throttle valve is closed and said valve means is conditioned in said first position, the breaker plate is positioned by said actuator in said original position, and when the throttle valve is opened with said valve means in said first position, the breaker plate is moved by said actuator in the retarding direction and subsequently moved in the advancing direction with the time lag upon switching-over of said valve means to said second position from said first position.
Dependencies are inferred from the claim text.