Ignition systems for internal combustion system
AssigneeLumenition Limited
InventorDavid H. Lewis
Life of this patent
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Abstract
A digital electronic ignition system employing two triggers for generating first and second voltage signals in response to engine revolutions. A first counter counts the number of second signal pulses during a predetermined interval of time from a given point in relation to the engine crank-shaft position. A memory which is operative from the first counter, includes a program or the desired advance of retard of the ignition timing, and operates a second counter to count said second signal pulses up to the number stored in the memory in order to initiate engine ignition at the optimum crank-shaft position.
Claims16
An electronic system for controlling the ignition timing of an internal combustion engine, said system including:
- means for generating separate first and second voltage signals in response to revolutions of the engine, each of said signals comprising pulses which change between first and second voltage levels at a predetermined constant frequency per engine revolution with the frequency of said second signal pulses being substantially greater than the frequency of said first signal pulses;
- first counting means for counting the number of said second signal pulses and producing a first output signal representative thereof;
- means for activating said first counting means for a predetermined time period in response to said first signal changing from said first voltage level at a first predetermined crank-shaft position to said second voltage level, whereby said first counting means counts the number of said second signal pulses over said predetermined time period and said first output signal is representative of the engine speed;
- memory means, including a program representative of the desired advance or retard of the ignition timing as a function of engine speed in accordance with the requirements of the engine, for producing, in response to said first output signal, a second output signal representative of the number of second signal pulses required to provide the desired ignition timing;
- second counting means for counting said second signal pulses and initiating engine ignition after a preset number of said second signal pulses have been counted;
- means for adjusting said preset number in response to said second output signal in accordance with engine requirements as determined during the previous firing cycle;
- and means for activating said second counting means in response to said first signal changing from said second voltage level to said first voltage level at a second predetermined crank-shaft position, whereby engine ignition is initiated when said preset number of said second signal pulses have been counted by said second counting means after activation thereof.
A digitial electronic ignition system for controlling the ignition timing of an internal combustion engine including:
- means for generating first and second engine related bistable square wave pulses, the first pulses being in synchronism with the crank-shaft revolutions, and the second pulses being of a frequency which is a multiple of the frequency of said crank-shaft revolutions;
- first counting means for counting the number of second engine related square wave pulses in a given predetermined time from a first crank-shaft position after top dead center, as determined by a first change in state of a said first engine related square wave pulse;
- storing means counting means for counting the second engine related square wave pulses from a second predetermined crank-shaft position before top dead center in the next firing cycle, as determined by a second change in state of a said first engine related square wave pulse;
- and means for initiating the spark when said second counting means has counted the second engine related square wave pulses up to the value stored in said storing means during the previous firing cycle.
Dependencies are inferred from the claim text.