Electronic control system for internal combustion engine injectors

Claim 2

In an internal combustion engine provided with a plurality of fuel injectors, an arrangement for controlling the injection of fuel, comprising a bistable flip-flop, a pulse generator controlled by the engine for controlling the operation of the flip-flop at a rate defined by the speed of rotation of the engine to make said flip-flop produce a start of injection signal, a relaxation oscillator adapted to produce high frequency pulses of fixed frequency, a system adapted to transform said pulses into a train of rectangular pulses at said fixed frequency, means controlled by at least one parameter governing the operation of the engine for deFining the duration of said rectangular pulses, an integrating system adapted to integrate said rectangular pulses, means controlled by additional operative parameters of said engine and adapted to trigger the integrating system when the integrated amplitude has reached a predetermined level to thereby make the flip-flop produce an end-of-injection signal.

Claim 3

An arrangement as claimed in claim 1 wherein said oscillator is connected to said flip-flop so that the oscillator is started by said beginning-of-injection signal.

Claim 4

An arrangement as claimed in claim 1 further comprising an AND gate connected between said pulse-transforming system and said integrating system, means whereby the flip-flop opens said AND gate at each beginning-of-injection signal and closes said AND gate at each end-of-injection signal and means continuously energizing said relaxation oscillator so that the pulse transforming system continuously produces rectangular signals.

Claim 5

An arrangement as claimed in claim 1 wherein the oscillator includes a grounded condenser, two first resistances connected between said condenser and the flip-flop, a first transistor the emitter of which is connected with the condenser, two further resistances grounding the connecting point between the two first resistances the connecting point between said further resistances being connected with the base of said first transistor, a second transistor the collector of which is connected with the base of said first transistor and the base of which is connected with the collector of said first transistor and a third transistor the base of which is connected with the emitter of the second transistor and means connecting the connecting point between the two first resistances, the collector of the third transistor and the pulse transforming system, the emitter of the third transistor being grounded.

Claim 6

An arrangement as claimed in claim 1 wherein said pulse transforming system comprises a monostable multivibrator including a first, second and third transistor, a supply of voltage, a voltage divider constituted by two resistances in series between said supply of voltage and ground, the point connecting said two resistances being connected with the base of the first transistor and with the collector of the second transistor, a third resistance connecting the emitter of the first transistor with the supply of voltage, a connection between the collector of the first transistor and the base of the second transistor, a connection between the emitter of the second transistor and the base of the third transistor, a fourth resistance grounding the emitter of the second transistor, a lead grounding the emitter of the third transistor, a fifth resistance connecting the collector of the third transistor with the supply of voltage, a condenser one terminal of which is fed by said oscillator, a fourth transistor the base of which is connected with the second terminal of said condenser and the emitter of which is grounded, a sixth resistance grounding the base of the fourth transistor, a seventh resistance connecting the collector of the fourth transistor with the supply of voltage, and variable circuit means connected with the emitter of the first transistor and with the collector of the fourth transistor and controlled by said parameter governing the operation of the engine.

Claim 7

An arrangement as claimed in claim 5 wherein said adjustable circuit means comprises a condenser having two plates the spacing of which is controlled by said parameter governing the operation of the engine.

Claim 8

An arrangement as claimed in claim 5 wherein said adjustable circuit means is connected with the emitter of the first transistor and with the collector of the fourth transistor and is controlled by said parameter governing the operation of the engine and further including a fifth transistor the emitter of which is grounded, the base of which is connected with the collector of the third transistor, a diode connecting the collector of the fifth transistor with the emitter of the first transistor and a further resistance connecting said collector of the fifth transistor with the supply of voltage.