Electronic ignition system

An ignition system, comprising:

• ignition means operable in response to an actuating signal for supplying an ignition spark to an engine having a piston movable in a combustion chamber,
• detector means generating a reference timing signal indicative of each movement of the piston to a reference position in the engine,
• advance means receiving the reference signals and being operable in response thereto over an effective range of engine speeds including a predetermined idling speed and extending to higher engine speeds fo generating advanced timing signals in time leading relation to the reference timing signals,
• selector means receiving the reference timing signals and the advanced timing signals and being connected in controlling relation with said ignition means,
• control means receiving the reference timing signals and being operable in response thereto independently of said advance means and over a different range of engine speeds including cranking speeds and extending therefrom beyond the predetermined idling speeds for producing a first control signal as the engine accelerates to a predetermined speed and producing a second control signal at engine speeds above the predetermined speed,
• said control means comprising:
• speed sensing means including a capacitor and a charging network for charging the capacitor to a reference potential and switch means responsive to each reference timing signal for effecting alternate charging of the capacitor to the reference potential and then discharging the capacitor to a potential providing a speed signal representative of the speed of the engine,
• reference means producing a reference signal representative of the predetermined engine speed,
• comparison means operable in response to the speed signal and the reference signal for effecting the first control signal as the engine accelerates to the predetermined speed and effecting the second control signal at engine speeds above the predetermined speed,
• said selector means being responsive to the first control signal for supplying actuating signals to said ignition means in synchronism with the reference timing signals and responsive to the second control signal for supplying actuating signals to the ignition means in synchronism with the advanced timing signals,
• said selector means including signal processor means receiving the control signals from said speed sensing means and being operable in response to a clock pulse for producing selector signals determining the timing of the operation of said ignition means, and
• clock means responsive to the reference timing signals for supplying clock pulses to said signal processor means when said switch means reverses from discharging to charging the capacitor.