Fuel injection system for internal combustion engines

Claim 2

A fuel injection system for internal combustion engines comprising: first means for generating a time variable signal having a predetermined characteristic curve representative of a fuel injection time interval with respect to the intake manifold pressure; second means for producing a voltage signal having an amplitude indicative of a desired fuel injection time interval determined from actually measured engine parameters including at least the engine speed and the intake manifold pressure; and third means for initiating the generation of said time variable signal simultaneously with the beginning of each cycle of the fuel injection and producing a signal for ending the fuel injection of each cycle when said time variable signal reaches a value equal to the amplitude of said voltage signal.

Claim 3

A fueL injection system for internal combustion engines according to claim 1, wherein said first means includes a capacitor charging circuit and means for changing the time constant of said charging circuit to thereby control the rate of change of said time variable signal.

Claim 4

A fuel injection system for internal combustion engines according to claim 2 characterized by including a capacitor connected to the power source through a first charging circuit, and at least one further charging circuit connected to said capacitor through a reverse current blocking means and through a voltage dividing circuit divided to a voltage lower than the power source voltage.

Claim 5

In a fuel injection system for an internal combustion engine having means, responsive to manifold pressure and the speed of rotation of the engine, for generating first and second control signals respectively representative of said pressure and speed and having fuel injection valves to which fuel is supplied to operate the engine, the improvement comprising: first means, responsive to the rotation of the engine, for generating a first electrical signal synchronized with the rotation of the engine, representative of the engine fuel injection starting time; second means, responsive to the rotation of the engine and being synchronized therewith, for generating a second electrical signal representative of a predetermined function, the characteristics of which vary with respect to time; and third means receiving the first and second electrical signals, generated by said first, and responsive second means and receiving said first and second control signals, for supplying a fuel injection supply signal to a fuel injection valve in accordance with said first electrical signal and for terminating the generation of said fuel injection supply signal when said second electrical signal reaches a value determined by said first and second signals, whereby the amount of fuel supplied to the engine is controlled in accordance with said predetermined function.

Claim 6

In a fuel injection system for an internal combustion engine having means, responsive to manifold pressure and the speed of rotation of the engine, for generating first and second control signals respectively representative of said pressure and speed and having fuel injection valves to which fuel is supplied to operate the engine, the improvement comprising: first means, responsive to the rotation of the engine, for generating a first electrical signal synchronized with the rotation of the engine, representative of the engine fuel injection starting time; second means, responsive to the rotation of the engine and being synchronized therewith, for generating a second electrical signal representative of a predetermined function, the characteristics of which vary with respect to time; and third means receiving the first and second electrical signals, generated by said first, and responsive second means and receiving said first and second control signals, for supplying a fuel injection supply signal to a fuel injection valve in accordance with said first electrical signal and for terminating the generation of said fuel injection supply signal when said second electrical signal reaches a value determined by said first and second signals, whereby the amount of fuel supplied to the engine is controlled in accordance with said predetermined function.

Claim 7

A fuel injection system according to claim 4, wherein said second means comprises a segmented linear signal function generator for generating a voltage signal, the characteristics of which are linearly segmented with respect to the lapse of time from the start of the generation of said first signal by said first means.

Claim 8

A fuel injection system according to claim 4, wherein said third means comprises a voltage discrimination circuit for comparing the sum of said first and second control signals and said second signal with a prescribed electrical level for terminating said fuel injection supply signal when said sum reaches said prescribed electrical level.

Claim 9

A fuel injection system according to claim 6, wherein the second means comprises a segmented linear signal function generator for generating a voltage signal, the characteristics of which are linearly segmented with respect to the lapes of time from the start of the generation of said first signal by said first means.

Claim 10

A fuel injection system according to claim 7, wherein said segmented linear signal function generator comprises a first capacitor charging circuit responsive to a source of supply voltage for generating a voltage at the output thereof, the magnitude of which follows said predetermined function.

Claim 11

A fuel injection system according to claim 8, wherein said first capacitor charging circuit comprises a plurality of non-linear voltage generating circuits, each of which includes a non-linear current conducting element and a resistor element coupled between said source of supply voltage and a capacitor, across the terminals of which said voltage function is generated.

Claim 12

A fuel injection system according to claim 8, wherein said discrimination circuit comprises an Esaki diode and a first transistor having an input, output and control electrode, said Esaki diode being connected in parallel with said input and control electrode of said transistor, said second signal being supplied to the cOntrol input of said first transistor and said fuel injection supply signal being taken from the output electrode of said first transistor.

Claim 13

A fuel injection system according to claim 9, wherein said discrimination circuit comprises an Esaki diode and a first transistor having an input, output and control electrode, said Esaki diode being connected in parallel with said input and control electrode of said transistor, said second signal being supplied to the control input of said first transistor and said fuel injection supply signal being taken from the output electrode of said first transistor.

Claim 14

A fuel injection system according to claim 11, wherein said function generating circuit further includes a boot-strap transistor circuit connected between said capacitor charging circuit and the control electrode of said first transistor.

Claim 15

A fuel injection system according to claim 10, further including a differentiator circuit connected between the voltage supply source and the input of said discrimination circuit.

Claim 16

A fuel injection system according to claim 12, further including a differentiator circuit connected between the voltage supply source and the input of said discrimination circuit.

Claim 17

A fuel injection system according to claim 9, wherein said first means comprises a second capacitor charging circuit, responsive to the rotation of the engine, for generating said first electrical signal in response to the voltage across said second capacitor charging circuit.

Claim 18

A fuel injection system according to claim 15, wherein said second capacitor charging circuit comprises a capacitor and a switching circuit responsive to the rotation of the engine for generating a switching voltage to control the charging of the capacitor of said second capacitor charging circuit.

Claim 19

A fuel injection system according to claim 16, wherein said discrimination circuit comprises an Esaki diode and a first transistor having an input, output and control electrode, said Esaki diode being connected in parallel with said input and control electrode of said transistor, said second signal being supplied to the control input of said first transistor and said fuel injection supply signal being taken from the output electrode of said first transistor.

Claim 20

A fuel injection system according to claim 17, wherein said switching circuit comprises an electrical switch connected between said source of supply voltage and a transistor circuit connected across said electrical switch, the output of said transistor circuit being connected to one side of a capacitor for controlling the charging thereof, the other side of said capacitor being coupled to the input of said discrimination circuit.

Claim 21

A fuel injection system according to claim 18, further including a differentiator circuit connected between the voltage supply source and the input of said discrimination circuit.

Claim 22

A fuel injection system according to claim 18, further including a diode element connected between said electrical switch and the junction of the capacitor of said first capacitor charging circuit and said plurality of non-linear voltage generating circuits.