Ignition timing control device for an internal combustion engine

Claim 1

An ignition timing control device for an internal combustion engine having intake and exhaust passages and an exhaust gas recirculation system which includes an exhaust gas recirculation control valve and selectively recirculates exhaust gases from said exhaust passage to said intake passage, comprising: a vacuum advancer which has a diaphragm means and advances ignition timing of the engine in accordance with vacuum supplied to said diaphragm means, first and second passage means which alternatively connect said intake passage and said diaphragm means so as to conduct fluid pressure therebetween, a delay and hold means related with said second passage means which includes a check valve, a surge space and a delay means and delays transmission of vacuum from said intake passage to said diaphragm means effected through said second passage means, while it holds the largest vacuum generated in said second passage means for said diaphragm means, and a changeover means which changes over connection of said intake passage and said diaphragm means between a route through said first passage means and a route through said second passage means in accordance with operation of said exhaust gas recirculation system so that, when exhaust gas recirculation is not performed, said intake passage and said diaphragm means are connected through said first passage means, and, when exhaust gas recirculation is performed, said intake passage and said diaphragm means are connected through said second passage means.

Claim 9

The device of any one of claims 1 through 5, further comprising a thermostat which suppresses operation of said exhaust gas recirculation system when engine temperature is below a predetermined value.