Fuel injection arrangement for iternal combustion engines

Claim 2

In a fuel injection arrangement for an internal combustion engine, in combination, fuel injection control means; monostable circuit means with output connected to said injection control means and producing pulses of which the duration is dependent on an operating parameter of the engine for at least partly determining the operating time of said fuel injection control means and thereby the amount of fuel injected; bistable multivibrator means coupled to said engine and responsive to the engine rpm to generate pulses having a repetition frequency dependent on the speed of said engine; and pulse differentiating means connecting the output of said bistable multivibrator means to the input of said monostable circuit means and being responsive to the operation of the former to trigger the latter, said pulse differentiating means differentiating the output pulses of said bistable multivibrator means and forming thereby a trigger pulse for triggering said monostable circuit means, whereby the amount of fuel supplied by said fuel injection control means to the engine by the pulse duration of said monostable circuit means varies in accordance with the operating condition of the engine, said bistable multivibrator means comprising first and second transistors connected to be triggered between conductive and non-conductive states, respective switch means connected to each of said first and second transistors for triggering said respective transistor between its two states, and respective capacitor means connected to each of said switch means for delaying the triggering of the respective transistor when the respective said switch means are operated, said bistable multivibrator means having two outputs and said pulse differentiating means comprising an AND circuit connected to said two outputs to trigger said monostable circuit means when both of said first and second transistors are in the same conductive state.

Claim 3

In a fuel injection arrangement for an internal combustion engine, in combination, fuel injection control means; monostable circuit means with output connected to said fuel injection control means and producing pulses of which the duration is Dependent on an operating parameter of the engine for at least partly determining the operating time of said fuel injection control means and thereby the amount of fuel injected; bistable multivibrator means coupled to said engine and responsive to the engine rpm to generate pulses having a repetition frequency dependent on the speed of said engine; and pulse differentiating means connecting the output of said bistable multivibrator means to the input of said monostable circuit means and being responsive to the operation of the former to trigger the latter, said pulse differentiating means differentiating the output pulses of said bistable multivibrator means and forming thereby a trigger pulse for triggering said monostable circuit means, whereby the amount of fuel supplied by said fuel injection control means to the engine by the pulse duration of said monostable circuit means varies in accordance with the operating condition of the engine, said bistable multivibrator means comprising first and second transistors connected to be triggered between conductive and non-conductive states, respective switch means connected to each of said first and second transistors for triggering said respective transistor between its two states, and respective capacitor means connected to each of said switch means for delaying the triggering of the respective transistor when the respective said switch means are operated, said bistable multivibrator means having two outputs and said pulse differentiating means comprising an AND circuit connected to said two outputs to trigger said monostable circuit means when both of said first and second transistors are in the same conductive state, said AND circuit being monolithic integrated circuit including a gating transistor with first, second and third emitter diodes.

Claim 4

In a fuel injection arrangement for an internal combustion engine, in combination, fuel injection control means; monostable circuit means with output connected to said fuel injection control means and producing pulses of which the duration is Dependent on an operating parameter of the engine for at least partly determining the operating time of said fuel injection control means and thereby the amount of fuel injected; bistable multivibrator means coupled to said engine and responsive to the engine rpm to generate pulses having a repetition frequency dependent on the speed of said engine; and pulse differentiating means connecting the output of said bistable multivibrator means to the input of said monostable circuit means and being responsive to the operation of the former to trigger the latter, said pulse differentiating means differentiating the output pulses of said bistable multivibrator means and forming thereby a trigger pulse for triggering said monostable circuit means, whereby the amount of fuel supplied by said fuel injection control means to the engine by the pulse duration of said monostable circuit means varies in accordance with the operating condition of the engine, said bistable multivibrator means comprising first and second transistors connected to be triggered between conductive and non-conductive states, respective switch means connected to each of said first and second transistors for triggering said respective transistor between its two states, and respective capacitor means connected to each of said switch means for delaying the triggering of the respective transistor when the respective said switch means are operated, said bistable multivibrator means having two outputs and said pulse differentiating means comprising an AND circuit connected to said two outputs to trigger said monostable circuit means when both of said first and second transistors are in the same conductive state, said AND circuit being monolithic integrated circuit including a gating transistor with first, second and third emitter diodes.

Claim 5

A combination as defined in claim 1, including a respective voltage divider having first and second series connected resistance means connected to the base of each of said first and second transistors and defining a common junction; respective third resistance means connected between a respective said common junction and a respective one of said switch means; and wherein each of said capacitor means are connected to a respective said common junction.

Claim 6

A combination as defined in claim 2, wherein said first and second emitter diodes are turned off, and said third emitter diode is turned on to conduct a positive going pulse, when both of said first and second transistors are in the same conductive state; and said monostable circuit means comprise a first switching transistor, said switching transistor defining a first switch path that is turned on by said positive going pulse.

Claim 7

A combination as defined in claim 4, wherein said engine operating parameter is the intake manifold suction pressure, and including a second switching transistor having an output electrode and connected to said first switching transistor and turned on thereby when said first switching transistor conducts; and an intake-manifold-suction-pressure detector having a coil with a primary winding connected to said output electrode whereby there appears on said primary winding a voltage falling with an e function when said second transistor is turned on.

Claim 8

A combination as defined in claim 5, including a secondary winding for said coil; and wherein said monostable circuit means comprise third and fourth switching transistors connected to be triggered when said primary winding induces a voltage in said secondary winding.

Claim 9

A combination as defined in claim 6, including a temperature compensating diode connecting one end of said secondary winding to the base of said third switching transistor; and wherein the emitter of said third switching transistor is connected to the base of said first switching transistor, the collectors of said third and fourth switching transistors are connected together, and the emitter of said fourth switching transistor is connected to ground; and furtHer including resistance means connecting the collector of said third switching transistor to positive.

Claim 10

A combination as defined in claim 7, including resistance means connected between the collectors of said third and fourth switching transistors.

Claim 11

A combination as defined in claim 8, wherein the voltage induced in said secondary winding turns off said third and fourth switching transistors.

Claim 12

A combination as defined in claim 9, wherein said fourth switching transistor comprises an output electrode; and including a fifth switching transistor having a control electrode, and a switching path that is in parallel with said first switching path, and wherein said fourth switching transistor output electrode is connected to said fifth switching transistor control electrode.

Claim 13

A combination as defined in claim 10, including resistance means connecting said fourth switching transistor output electrode to said fifth switching transistor control electrode.

Claim 14

A combination as defined in claim 11, wherein said monostable circuit means comprise an output; and including logical circuit means having an input connected to said monostable circuit means output, and an output; amplifier circuit means connected to said logical circuit means output; and wherein said fuel injection control means comprise at least one fuel injection spray valve operatively connected to said amplifier circuit means.

Claim 15

A combination as defined in claim 12, wherein said logical circuit means comprise at least two switching transistors defining each a switching path and having a respective control electrode; and wherein said monostable circuit means output is connected to the control electrode of each of said two switching transistors, whereby the operation of the latter said switching transistors is dependent at least on the suction pressure in the intake manifold.

Claim 16

A combination as defined in claim 13, wherein each of said first and second transistors has an output; and including a respective further switching transistor having each a control electrode and defining a switching path in series with each of said two switching transistors; and including a respective inverting stage connecting each of the control electrodes of said further switching transistors to a respective output of said first and second transistors.

Claim 17

A combination as defined in claim 14, wherein each of said further switching transistors has an output electrode; and including a respective first amplifier transistor having a control electrode and connected to each of the latter said output electrodes.

Claim 18

A combination as defined in claim 15, including a plurality of said fuel injection spray valves; respective pairs of series connected resistors connecting different ones of said further switching transistor output electrodes to positive, and wherein the control electrode of each said first amplifier transistor is connected to the junction between the resistors of a respective said pair; and further including respective second amplifier transistors having each a control electrode connected to the collector of a respective said first amplifier transistor, and an output electrode connected to operate at least one of said fuel injection spray valves.

Claim 19

A combination as defined in claim 16, including a respective power transistor connecting to each said second amplifier transistor output electrode.

Claim 20

A combination as defined in claim 17, including for each said second amplifier transistor respective output transistor having an output electrode and a control electrode, said control electrode being connected to the control electrode of a respective said second amplifier transistor; and a test clip connected to the output electrodes of said output transistors.

Claim 21

A combination as defined in claim 18, including resistance means connected between said test clip and said output electrodes.

Claim 22

A combination as defined in claim 19, including current limiting means for limiting The circuit current flow in the event of wrong polarity.

Claim 23

A combination as defined in claim 20, wherein said circuit means are at least partly monolithic integrated circuits.