Ignition systems for internal combustion engines
AssigneeLumenition Limited
InventorEric H. Ford
Life of this patent
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Abstract
The advance and retard of the spark ignition in an ignition system of an internal combustion engine is achieved electronically by generating two series of pulses in synchronism with the engine using one series as a reference for maximum advance and the other series to operate a counter to count down the requisite number of pulses beyond the maximum advance point before the spark is initiated, the count of the counter being varied from a computer in accordance with speed and/or load on the engine.
Claims10
An electronic device for controlling the advance and retard of the ignition timing of an internal combustion engine in accordance with engine requirements, including means for generating a first series of square-wave voltage pulses in synchronism with the engine revolutions to provide a series of alternate first and second voltage levels;
- means for generating a second series of square-wave voltage pulses also in synchronism with the engine revolutions and at a fixed multiple of the first series of square-wave voltage pulses, so that the frequency of the second series of voltage pulses is greatly in excess of the frequency of the first series of voltage pulses;
- means for counting a predetermined number of the second series of voltage pulses from a [predetermined] point [in relation to the first series of voltage pulses,] at which the logic level of the first series of pulses changes to the first voltage level , the number of said pulses counted depending on the engine requirements;
- means for producing an output at the first voltage level from said counting means after said count has been completed;
- means for detecting the presence of both an output at the first voltage level from the first pulse generating means[,] and an output at the first level from the counting means [in order to initiate] and, upon such occurrence, initiating the production of a spark and causing spark duration to begin for the combustion of the fuel, the outputs from both the counting means and the first pulse generating means remaining at the first voltage level until the logic level of the first pulse generating means changes to a second voltage level at a given engine crankshaft position and causes termination of spark duration ;
- and means for continuously varying the count of the counting means, so as to advance and retard the ignition timing in accordance with the requirements of the engine.
An electronic device for controlling the advance and retard of the ignition timing of an n cylinder internal combustion engine, having an ignition coil with primary and secondary windings, said device including an opaque disc driven in synchronism with the engine;
- a series of equi-spaced slits around the disc;
- n equi-spaced apertures in the disc;
- a pair of infra-red radiation sources and a pair of infra-red radiation detectors arranged on opposite sides of the disc, [the] a first element of each pair being arranged to cooperate with said n apertures and [the] a second element of each pair being arranged to cooperate with the slits, [one] a first one of said infra-red [detector] detectors generating a first series of square-wave voltage pulses in synchronism with the engine revolutions, to provide a series of alternate first and second voltage levels;
- [the other] a second one of said infra-red [detector] detectors generating a second series of square-wave voltage pulses also in synchronism with the engine revolutions, and at a fixed multiple of the first series of square-wave voltage pulses, so that the frequency of the second series of voltage pulses is greatly in excess of the first series;
- a [frequency divider circuit] counter for counting [the pulses generated from the second infra-red detector at a starting point determined when said respective first series of pulses change from the second to the first voltage level] a predetermined number of the second series of voltage pulses from a point at which the logic level of the first series of voltage pulses changes to the first voltage level, the number of said pulses counted depending on engine requirements;
- means for producing an output at the first voltage level from said counter after said count has been completed ;
- a computer connected to receive [analogue] analog information from a pair of inputs regarding the requirements of the engine, and providing a corresponding digital output, in accordance with that information for changing the count of the [frequency divider, the frequency divider producing an output after the predetermined count] counter;
- logic circuitry for detecting the presence of both an output at the first voltage level from the first detector and an output at the first voltage level from said counter ;
- a transistorized power stage in series with the primary winding of the ignition coil, the power stage being rendered non-conductive [at the instant when there is a first voltage level output from the frequency divider and the first detector thereby initiating the spark for ignition, the advance and retard of the ignition timing being continuously adjusted in accordance with engine requirements] in response to the logic circuitry detecting the presence of both outputs and thereby initiating the production of a spark and causing spark duration to begin for the combustion of the fuel, the outputs from both said counter and the first detector remaining at the first voltage level until the logic level of the first detector changes to a second voltage level at a given engine crankshaft position .
Dependencies are inferred from the claim text.