Ignition control system for internal combustion engines

Claim 2

An ignition control system for internal combustion engines comprising: a battery; a timing pulse generator for generating timing pulses with the cycle time varying with engine operting conditions; a reference signal generator for generating a reference signal; a computation circuit, connected to said generator and said reference signal generator, for producing control pulses, by (1) subtracting a constant time period from said cycle time which is measured in response to said reference signal and (2) subtracting the remainder from said cycle time which is currently measured, thereby approximating the width of said control pulses to said constant time period, an ignition coil, connected to said battery and said computation circuit, for providing ignition energy in response to said control pulses from said computation circuit; and at least one spark plug, coupled to said ignition coil, for providing ignition sparks.

Claim 3

An ignition control system as claimed in claim 1, wherein said reference signal generator comprises an oscillator for generating clock pulses of a fixed frequency; and said computation circuit comprises: a counter, connected to said oscillater, for counting up said clock pulses in each cycle of said timing pulses; a register, connected to said counter, for memorizing output signals of said counter; a subtractor, connected to said register and being supplied with a predetermined signal, for producing output signals indicative of the difference between said time period and said constant time period; and a comparator, coupled to said counter and said subtractor, for comparing said output signals from said subtractor with said output signals in a following cycle of said timing pulses, whereby said control pulses are generated while said output signals of said counter exceeds said output signals of said subtractor.

Claim 4

An ignition control system as claimed in claim 1, wherein said reference signal generator comprises: a source for supplying a constant current; and a first capacitor, connected to said source for storing said constant current in each cycle of said timing pulses; and wherein said computation circuit comprises; a second capacitor, coupled to said first capacitor through a switch responsive to said timing pulses, for producing a voltage indicative of one cycle time period of said timing pulses upon closure of said switch; an amplifier, connected to said second capacitor and a voltage source which supplies with a predetermined voltage indicative of said constant time period, for producing a difference voltage indicative of the difference between said two time periods; and a comparator, connected to said first capacitor and said amplifier, for comparing said difference voltage with a voltage developing across said first capacitor in proportion to the time period in the following cycle of said timing pulses, whereby said control pulses are generated while said voltage across said first capacitor exceeds said difference voltage.

Claim 5

An ignition control system for internal combustion engines having at least one spark plug comprising; a battery; a timing pulse generator fo generating timing pulses in accordance with engine operating conditions; first means, connected to said timing pulse generator, for measuring the time period of said timing pulses in each cycle thereof; second means, connected to said first means, for memorizing the measured time period of said timing pulses; third means for providing a constant time period; fourth means, connected to said second means and said third means, for subtracting said constant time period from said measured time period; fifth means, connected to said first means and said fourth means, for comparing a subtraction-resultant time period with the time period in the following cycle of said timing pulses; and an ignition device, connected to said battery and said fifth means, for firing said spark plug in synchronism with said timing pulses, said ignition device being supplied with the eletric power from said battery only while the timer period of said timing pulses exceeds said subtraction-resultant time period.

Claim 6

An ignition control system for internal combustion engines having at least one spark plug comprising; a battery; a timing pulse generator fo generating timing pulses in accordance with engine operating conditions; first means, connected to said timing pulse generator, for measuring the time period of said timing pulses in each cycle thereof; second means, connected to said first means, for memorizing the measured time period of said timing pulses; third means for providing a constant time period; fourth means, connected to said second means and said third means, for subtracting said constant time period from said measured time period; fifth means, connected to said first means and said fourth means, for comparing a subtraction-resultant time period with the time period in the following cycle of said timing pulses; and an ignition device, connected to said battery and said fifth means, for firing said spark plug in synchronism with said timing pulses, said ignition device being supplied with the eletric power from said battery only while the timer period of said timing pulses exceeds said subtraction-resultant time period.