Abstract: A fail safe device for isolating the revolution limiter from the ignition system of an internal combustion engine, in which the output stage of the revolution limiter is continuously monitored to ascertain whether or not it is absorbing ignition pulses at a speed lower than the limiting speed. In the event that the absorption of ignition pulses is taking place at a speed lower than the limiting speed, the fail safe device becomes operative upon the engine revolutions falling below a given value and causes a fuse in series with the output stage of the revolution limiter to blow, thus isolating the revolution limiter from the ignition system to allow ignition to be instantly re-established in the event of a fault occuring in the revolution limiter.

Abstract: A monolithic Darlington in which the transistors forming the Darlington pair are formed on a substrate together with a fourth terminal in addition to the normal three terminals provided for a Darlington pair, the fourth terminal being connected to the base electrode of the second transistor and the emitter electrode of the first transistor. The addition of the fourth terminal enables a control circuit for controlling the rate of switch off to be connected between the fourth terminal and the command collector electrode, this removing the effect which the stored charge on the base electrode of the first transistor has on the switching rate of the Darlington pair, thus enabling a faster switching rate to be achieved.

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.

Abstract: A revolution limiter for internal combustion engines having a circuit for detecting when the engine revolutions exceed a given maximum permitted value, and a circuit for limiting the voltage on the primary winding of the coil comprising a semiconductor device which will breakdown above a given threshold voltage and a semiconductor switch connected in series between the terminal of the primary winding remote from the positive line connection and ground, the semiconductor switch being rendered conductive by the detection circuit in order to limit the voltage on the primary winding of the coil and thus prevent a spark occurring when said given limit is exceeded.

Abstract: A closed loop electronic ignition system for internal combustion engines, in which a comparison is made between a signal derived from a fixed predetermined crank-shaft angle, and a signal derived from the commencement of the second stage of combustion within a cylinder of the engine, and if non-coincidence is detected between the two signals, the ignition timing is either advanced or retarded so as to maintain coincidence between the signals, so that the second stage of combustion always occurs at the fixed predetermined crank angle, the spark then being extinguished by switching the ignition coil "on" at this predetermined crank-shaft angle, irrespective of engine requirements.

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.

Abstract: Detection of the combustion within a cylinder of an internal combustion engine by sensing the visible and/or infra-red radiation emitted on combustion by means of a quartz window in the cylinder wall or head, a fiber optic light guide and a photo-transistor. The detection may be utilized in ignition timing, or determining engine R.P.M. or cylinder misfire.

Abstract: The quantity of fuel injected in a fuel injection 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 fuel injection is initiated, the count of the counter being varied from a computer in accordance with speed and/or load on the engine.

Abstract: An opto-electronic ignition system for an internal combustion engine in which radiation falls on to and is cut off from a photo-transistor in timed sequence with the engine, and in which between the photo-transistor and the primary winding of the ignition coil there is a plurality of switching Darlington pairs, each Darlington switching in inverse relation to its neighbor, and the first Darlington switching in inverse relation with the photo-transistor. The circuit is designed so that it will reliably operate in engine compartment temperatures above 125.degree. C.

Abstract: In an ignition system of an internal combustion engine the provision of a device for fast switching the primary circuit, this device including an infra-red radiation source and an infra-red radiation sensitive element, the radiation path being interrupted in timed relation to the engine revolutions whereby switching current is provided which is amplified for fast switching transistorized elements and applied to the primary winding of the ignition coil. Advance or retard of the ignition system can be achieved in relation to speed and/or load conditions on the engine by altering the line of sight between the radiation source and the radiation sensitive element in relation to a device which interrupts the radiation in timed relation to the engine revolutions.

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.