Method of, and apparatus for ignition timing in internal combustion engines

Claim 5

Apparatus as claimed in claim 2, characterized in that the time delay circuit comprises a timing capacitor and a transistor switch connected to the output of the amplifier and which in the absence of a position pulse short-circuits the timing capacitor, a charging circuit for the timing capacitor which charges the capacitor in the presence of said position pulse, and a difference amplifier which delivers a signal at the output terminal of the delay circuit when the capacitor voltage exceeds a reference voltage.

Claim 6

Apparatus as claimed in claim 2, characterized in that the pulse generator comprises a two-stage transistor amplifier including a first transistor in common emitter configuration with its base connected to the output of the position pulse amplifier and the collector-circuit connected by means of a capacitor to a second transistor in common emitter configuration, and the collector circuit of the second transistor includes a terminal from which the reference pulse may be derived.

Claim 7

Apparatus as claimed in claim 2 characterized in that the pulse width comparison device comprises two current source circuits, the first of which supplies current to a storage capacitor through a transistor switch connected to the pulse generator, whereas the second current source circuit takes current from the storage capacitor via a second transistor switch connected to the output of the delay circuit, the comparison device further including a differential amplifier with one input terminal connected to the storage capacitor, and the other input terminal connected to a reference voltage.

Claim 10

The method of claim 6 comprising the further step of changing the reference quantity so as to change the instant at which the trigger signal occurs.

Claim 11

The method of claim 6 comprising the further step of changing the measurment parameters when measuring the time period between the trigger signal and the second signal thereby to change the instant at which the trigger signal occurs.

Claim 12

Apparatus as claimed in claim 5 wherein said time delay circuit comprises a timing capacitor and a third transistor switch connected to the output of the differential amplifier, said third transistor switch being responsive to the position pulse so that in the absence of said pulse it short-circuits the timing capacitor, a charge circuit for the timing capacitor that includes a current source output of the differential amplifier and is arranged to charge the timing capacitor when the position pulse is present to open the third transistor switch, and a difference amplifier which delivers a signal at an output terminal of the delay circuit when the timing capacitor voltage exceeds a reference voltage.

Claim 13

Apparatus as claimed in claim 2 wherein the crankshaft transducer comprises a disc-shaped part adapted to rotate with the crankshaft and including sectors having arc lengths corresponding to the desired angular positions, and a pick-up member disposed close to the disc-shaped part so as to detect the presence of a sector and thereby derive said position pulse.

Claim 14

Apparatus for timing the ignition in an internal combustion engine as a function of engine speed comprising, a crankshaft transducer for deriving first and second signals during the compression stroke of a cylinder piston, the occurrence of the first signal representing a first piston position prior to the instant of ignition and the occurrence of the second signal representing a second later position of the piston near top dead center, a time delay circuit with an input coupled to said transducer and responsive to said first signal to derive a time delayed trigger signal at an output terminal, a comparison device with one input connected to the output of the time delay circuit, a reference source that delivers to a second input of the comparison device an electric reference quantity related to the inflammation time of the gas mixture in a cylinder, means connecting the output of the comparison device to a control input of the time delay circuit which adjusts the delay time thereof, said time delay circuit being operative to supply the second signal to said one input of the comparison device whereby the time interval between the trigger signal and the second signal is measured and compared with the reference quantity related to the inflammation time period to produce a control signal at the output of the comparison device which, in the event of a deviation of the compared time periods, is applied to said delay circuit control input to adjust the delay time of the time delay circuit for said first signal in a sense to compensate for the engine speed, and means for applying the trigger signal at the output of the delay circuit to a device for controlling the operation of the engine ignition contact breaker.

Claim 15

Apparatus for timing the ignition in an internal combustion engine as a function of engine speed comprising, a crankshaft transducer for deriving first and second signals during the compression stroke of a cylinder piston, the occurrence of the first signal representing a first piston position prior to the instant of ignition and the occurrence of the second signal representing a second later position of the piston near top dead center, a time delay circuit with an input coupled to said transducer and responsive to said first signal to derive a time delayed trigger signal at an output terminal, a comparison device with one input connected to the output of the time delay circuit, a reference source that delivers to a second input of the comparison device an electric reference quantity related to the inflammation time of the gas mixture in a cylinder, means connecting the output of the comparison device to a control input of the time delay circuit which adjusts the delay time thereof, said time delay circuit being operative to supply the second signal to said one input of the comparison device whereby the time interval between the trigger signal and the second signal is measured and compared with the reference quantity related to the inflammation time period to produce a control signal at the output of the comparison device which, in the event of a deviation of the compared time periods, is applied to said delay circuit control input to adjust the delay time of the time delay circuit for said first signal in a sense to compensate for the engine speed, and means for applying the trigger signal at the output of the delay circuit to a device for controlling the operation of the engine ignition contact breaker.

Claim 16

Apparatus for timing the ignition in an internal combustion engine as a function of engine speed comprisIng, a crankshaft transducer for deriving first and second signals during the compression stroke of a cylinder piston, the occurrence of the first signal representing a first piston position prior to the instant of ignition and the occurrence of the second signal representing a second later position of the piston near top dead center, means responsive to said first and second signals for deriving a rectangular waveform signal whose leading and trailing edges correspond to said first and second signals, respectively, a time delay circuit with an input coupled to the output of said waveform signal deriving means and responsive to said rectangular waveform signal to time delay the leading edge thereof and to pass the trailing edge without any time delay, a comparison device with one input connected to the output of the time delay circuit, a reference source that delivers to a second input of the comparison device an electric reference quantity determined by the inflammation time of the gas mixture in a cylinder, means connecting the output of the comparison device to a control input of the time delay circuit which adjusts the delay time thereof as a function of the difference of the input signals to the comparison device and in a sense to reduce said difference to zero by adjusting the delay of the leading edge of the rectangular waveform signal in the appropriate direction, and means for deriving an output signal from the output of the time delay circuit for controlling the engine ignition point in synchronism with the leading edge of the rectangular waveform signal.

Claim 17

Apparatus for timing the ignition in an internal combustion engine as a function of engine speed comprisIng, a crankshaft transducer for deriving first and second signals during the compression stroke of a cylinder piston, the occurrence of the first signal representing a first piston position prior to the instant of ignition and the occurrence of the second signal representing a second later position of the piston near top dead center, means responsive to said first and second signals for deriving a rectangular waveform signal whose leading and trailing edges correspond to said first and second signals, respectively, a time delay circuit with an input coupled to the output of said waveform signal deriving means and responsive to said rectangular waveform signal to time delay the leading edge thereof and to pass the trailing edge without any time delay, a comparison device with one input connected to the output of the time delay circuit, a reference source that delivers to a second input of the comparison device an electric reference quantity determined by the inflammation time of the gas mixture in a cylinder, means connecting the output of the comparison device to a control input of the time delay circuit which adjusts the delay time thereof as a function of the difference of the input signals to the comparison device and in a sense to reduce said difference to zero by adjusting the delay of the leading edge of the rectangular waveform signal in the appropriate direction, and means for deriving an output signal from the output of the time delay circuit for controlling the engine ignition point in synchronism with the leading edge of the rectangular waveform signal.