Engine ignition system having improved warmup advanced timing control

An ignition system for an internal combustion engine of the type which has an ignition capacitor means, a means to charge said ignition capacitor means and an ignition capacitor discharge means connected to discharge said ignition capacitor means in response to receiving a trigger pulse applied thereto, the system comprising:

• trigger pulse generating means for producing trigger pulses in synchronism with the engine, said trigger pulse generating means being adapted to provide a first timing characteristic for discharging said ignition capacitor means and a second timing characteristic that is advanced a predetermined time relative to said first timing characteristic, said trigger pulse generating means providing said second timing characteristic in response to an advance signal being applied thereto;
• means for selectively generating an advance signal for application to said trigger pulse generating means, said advance signal generating means producing said advance signal only when enabled;
• means for enabling said advance signal generating means for a variable time period after startup of the engine, said enabling means including a voltage storing means and first and second circuit means, each of said circuit means being adapted to discharge said voltage storing means, said voltage storing means being charged to a first predetermined voltage level during startup of the engine and enabling said advance signal generating means when the voltage level of said voltage storing means is above a second predetermined level that is lower than the first predetermined level;
• said first circuit means including a first resistance means and a switch means, said first circuit means being adapted to discharge said voltage storing means below said second predetermined level in a predetermined minimum time period when said switch means is closed, said switch means switching to a closed condition in response to the engine reaching a minimum operating temperature;
• said second circuit means including a second resistance means having a resistance value that varies inversely with temperature, said second circuit means being adapted to discharge said voltage storing means below said second predetermined level in a variable time period greater than said minimum time period during operation of the engine.

An ignition system for an internal combustion engine of the type which has a starter and a source of power for operating the starter, said system being of the type which has an ignition capacitor means, a means to charge said ignition capacitor means and an ignition capacitor discharge means connected to discharge said ignition capacitor means in response to receiving a trigger pulse applied thereto, the system comprising:

• trigger pulse generating means for producing trigger pulses in synchronism with the engine, said trigger pulse generating means being adapted to provide a first timing characteristic for discharging said ignition capacitor means and a second timing characteristic that is advanced a predetermined time relative to said first timing characteristic, said trigger pulse generating means providing said second timing characteristic in response to an advance signal being applied thereto;
• means for selectively generating an advance signal for application to said trigger pulse generating means, said advance signal generating means producing said advance signal only when enabled;
• means for enabling said advance signal generating means for a time period that varies between a minimum time period and a temperature dependent longer variable time period after startup of the engine, said enabling means including a voltage storing means and at least first and second circuit means each of which is capable of discharging said voltage storing means, said voltage storing means being charged to a first predetermined voltage level during startup of the engine and enabling said advance signal generating means when the voltage level of said voltage storing means is above a second predetermined level that is lower than the first predetermined level;
• said first circuit means including a first resistance means and a switch means, said first circuit means being adapted to discharge said voltage storing means below said second predetermined level in a predetermined minimum time period when said switch means is closed, said switch means switching to a closed condition in response to the engine reaching a minimum operating temperature;
• said second circuit means including a second resistance means having a resistance value that varies with temperature, said second circuit means being adapted to discharge said voltage storing means below said second predetermined level in a variable time period greater than said minimum time period during operation of the engine, said variable time period having a shorter duration as said resistance value decreases with an increased temperature.