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An ignition system for an internal combustion engine, such as an outboard marine engine, which includes an advanced timing schedule, a normal timing schedule, and a circuit for switching between the two schedules or disabling both schedules based upon engine operating conditions. The ignition system

An ignition system for an internal combustion engine, such as an outboard marine engine, which includes an advanced timing schedule, a normal timing schedule, and a circuit for switching between the two schedules or disabling both schedules based upon engine operating conditions. The ignition system includes an optoelectronic time base generator which produces two sets of timing pulses relative to crankshaft position which are normal timing pulses and advanced timing pulses. The time base generator comprises a LED-phototransistor pair and an encoder disk attached to the crankshaft with slots to interrupt the emission path between LED-phototransistor pair. The normal pulses are generated based upon the trailing edge of each slot while the advanced pulses are generated based up the leading edge, wherein the width of the slots indicate the degree of advancement of the advanced schedule over the normal schedule. Both schedules are inhibited based on a high overspeed condition and a low overspeed condition when the engine is overheated, wherein there is a smooth tarnsition between the two conditions.

대표청구항 ▼

A time base generator for an ignition system of an internal combustion engine having a crankshaft, said time base generator comprising: an encoder disk which rotates synchronously with the crankshaft of the engine and includes a plurality of timing features of a predetermined width which are at fixe

A time base generator for an ignition system of an internal combustion engine having a crankshaft, said time base generator comprising: an encoder disk which rotates synchronously with the crankshaft of the engine and includes a plurality of timing features of a predetermined width which are at fixed locations relative to the crankshaft and includes at least one synchronizing feature which is at a fixed location relative to the crankshaft and to at least one of said timing features; detector means for detecting the presence or absence of said timing features and said at least one synchronizing feature and for generating digital signals representative thereof; and pulse generating means for generating a first pulse train from the trailing edge of each timing feature represented in said digital signal and for generating a second pulse train from the leading edge of each timing feature represented in said digital signal whereby the pulses of said second pulse train are advanced from the pulses of said first pulse train by a predetermined angular rotation of the crankshaft determined by the width of each timing feature.