DE2051959A1 - Fuel cut-off device for internal combustion engines - Google Patents

Description

t / ■ * t i. m ι M ti il η LI »_ 2051959 Dipi.-chem. Dr. D. Thomsen Dipt m _g H. Tiedtke
Dipi.-chem. O. Bühiing Dipi.-mg. R. Kinne MUNICH 2
VAL 33
TEL. 0611/226894
295051
CABLES: THOPATENT
TELEX: TO FOLLOW Dipi.-ing. W.Weinkauff FRANKFURT (MAIN) 50
FUCHSHOHL 71
TEL 0811/51 «66

Reply requested to: Please reply to:

8000MQ

Oct. 22, 1970 - case PG23-7Q24

Nissan Motor Company, Limited Yokohama City, Japan

Fuel cut-off device for internal combustion engines

The invention relates generally to a fuel system for an internal combustion engine, and more particularly to a device for inclusion in such a system for blocking the fuel supply during the delay, thereby reducing the amount of carbon monoxides and reduce hydrocarbons in engine exhaust.

Air pollution from automobile exhaust creates significant social problems, so that the

1098.18 / U90

2051

Development of pollution-free vehicles highest
Has to be observed by most motor vehicle manufacturers.
Numerous anti-pollution measures taken by these manufacturers include shutting off the fuel supply to the cylinders during deceleration, because this causes the carbon monoxide and hydrocarbons in the exhaust gases to be eliminated.

heblioh be diminished. With an ordinary force

Substance blocking device for a vehicle internal combustion engine a shut-off valve is used to shut off the fuel supply determining the presence, one of the following Locked states or conditions:

(1) When the suction pipe pressure is above a certain Value is |

(2) when the relationship between the engine speed-P speed and the throttle valve position falls within a predetermined range.

Such a fuel shut-off device works in such a way that it closes the shut-off valve _? if
the throttle valve has reached its fully gffichlosene position so that still a considerable amount of
cleaning remains.

The object of the invention is to provide a fuel cut-off device for a motor vehicle internal combustion engine that avoids the aforementioned disadvantages.

This object is achieved by a first 'device, which is operatively associated with a throttle valve to a To generate a voltage signal that corresponds to the position of the throttle valve, by a second device that is connected to the first device is connected and a fuel cut signal generated when the time derivative of the voltage signal exceeds a predetermined value, and by a third device responsive to the fuel cutoff signal responds to the fuel supply to the cylinders lock.

The invention is illustrated in the following with the aid of a schematic Drawings explained in more detail.

Fig. 1 shows schematically a fuel cut-off device according to the invention in a conventional fuel injection system;

Fig. 2 shows an example of a throttle valve position detector or throttle position detector at the fuel cut-off device "according to FIG. 1;

VO 9 8 1 8 / U 9 0

Fig. 3 is a circuit diagram showing another arrangement of the throttle position detector j

Fig. U is a circuit diagram of a fuel cut off '' signal generator of Figure 1;

Figures 5 (a) through 5 (c) illustrate the throttle valve ™ position, 'the speed of movement of the

Throttle and the fuel cut signal;

Fig. 6 is a circuit diagram of a check valve controller;

7 illustrates an injection pulse control circuit or driver circuit of the fuel injection system of Fig. 1;

Fig. 8 Ca) to 8 Ce) show how the amount of carbon monoxide and hydrocarbons in the exhaust gases by the fuel shut-off device according to the invention is decreased;

FIG. 9 is a representation corresponding to FIG. 1, showing the locking device according to the invention in use in a fuel delivery system the type of carburetor made clear.

.:. . 10981B / U9Ö "'' '.'

In Fig. 1 is a fuel injection system with. a fuel shut-off device according to the invention according to an embodiment of the invention shown. In the figure, reference numeral 10 denotes a throttle valve or a throttle valve that can be tilted in a throttle chamber 11 to allow more or less air flow. The throttle chamber 11 is connected to the suction line

12 in connection that is on the side of a cylinder block

13 is arranged. An injection nozzle sits in the intake line 12 11 for injecting fuel in spray form. The nozzle does not have to be in the suction line, but can also be arranged in the same way that they are immediately downstream of the inlet valve or Intake valve injected into the cylinder of the engine. A pump, not shown, is provided to take the fuel Provides pressure from a fuel source to a pressure regulator that controls the pressure of the fuel supplied to the nozzle controls. The fuel coming from the pressure regulator goes through a shut-off valve 15 to the nozzle IH, which is through a Solenoid operated valve 16 is controlled.

The throttle valve 10 is operationally connected to an accelerator pedal in the driver's compartment via a mechanical linkage (not shown). In the mechanical linkage there is a throttle valve switch 21 which is closed when the throttle valve is in its fully closed position 109818 / UdO

2051351

is brought. Also located in the mechanical linkage is a throttle valve position detector 17 which generates a voltage signal that corresponds to the position of the throttle valve 10. The Fig. 2 schematically shows an example of the Drosselklappenstellungsd "Tektor 17 which has a sliding contact 18, which upon opening and closing the throttle valve 10 to a resistor 19 W back and vorgleitet. One end of the resistor 19 ″ is connected to a direct voltage source, for example a battery 20, while the other end is connected to ground The throttle valve is closed is denoted by 21 in FIG. 2.

3 shows schematically a further embodiment form of the throttle position detector 17. The part of the circuit shown in the left section, the one Having transistor 22 is an oscillator circuit which has a constant oscillator frequency. The output of the oscillator circuit is taken from an inductance coil, which is coupled to another inductance coil 2 * 1, a shield plate 25 being provided therebetween. The shield plate 25 is operationally connected to the mechanical linkage in such a way that it provides minimal shielding

'1090187 1440 ...

protection is provided when the accelerator pedal is fully depressed, ie when the throttle valve is fully open. The inductance coil 24 supplies an input energy to a DC voltage watrilerschaltung with a transistor 26 ·, this DC voltage converter circuit converts the input energy supplied by the inductance coil 2 k into a DC voltage corresponding thereto. Thus, a DC voltage E is obtained from the output terminal 27 of the converter circuit, which depends on the throttle valve position.

The DC voltage signal corresponding to the throttle valve position is sent to a fuel cut signal generator 30 applied, which differentiates the DC voltage E and generates a fuel cut-off signal when the Absolute value de? time derivative dE / dt a predetermined Value exceeds. Since the time derivative dE / dt is proportional to the speed of movement of the throttle valve 10, the fuel cut signal is generated when the speed at which the throttle valve 10 returns to its fully closed position is a predetermined one Value exceeds.

The fuel cut-off signal is applied to a cut-off valve control device 31, the output of which is sent to the cut-off valve 15 is connected. The control device 31

2051S59

■ - 8 -

operates in response to the fuel cut-off signal in such a way that it keeps the shut-off valve 15 closed and thereby the fuel supply from the pressure regulator to the injection nozzle 14 interrupts. In addition to the fuel cut signal supplied from the throttle position detector 17 the shut-off valve control device 31 receives two signals, the engine speed and the full

P show the closed position of the throttle valve 10. the

Motor speed is sensed by a trigger device 32 driven by the motor, as shown in the left part of FIG. 1 and which is accommodated in a distributor housing (not shown). The device 42 loading _; sits a cam 33, which is seated on a shaft 34 driven by the motor, and two trigger switches 3b and 36, which are actuated alternately by rotating the cam 33 as a function of the motor speed. the

fc stationary contacts 37 and 38 of the trigger switch .35 and 36 are connected to a battery 39 via resistors 40 and 41, respectively connected and also to the check valve control device 31. If the cam 33 is dependent on the motor rotated by the engine speed, a signal with a ** engine speed proportional Repetition rate from the motor driven trigger device 32 to the check valve controller 31 delivered. The fully closed position of the throttle valve is determined by the switch 21 (Fig. 2 and 3), the

'109818 / U9.0

is operationally assigned to the mechanical linkage according to the previous description. The use of the control device 31 as a function of the engine speed and the fully closed position of the throttle valve 10 is shown below described in detail.

The pulse signal that increases the engine speed <

is also applied to a computing circuit 42 which, in response to engine speed and other engine operating conditions such as intake manifold pressure and engine temperature, calculates an appropriate pulse width of injection pulses which actuate injector 16. The injection pulse from the computer circuit 42 goes through a fuel cut-off control device 43 to each of the solenoid-operated injection valves 16. The fuel cut-off control device 43 is connected to the lock-signal generator 30 with the aid of a supply line 44, so that, depending on the fuel cut-off signal, the control device 43 is blocked so that no Einspritζimpuls is transmitted to the injection valve 16. If a fuel cut-off signal is generated, the injection valve 16 is closed simultaneously with the closure of the cut-off valve 15.

FIG. 4 shows, as an example, a circuit of the fuel cut-off signal generator 30 according to FIG. 1. The circuit is a monostable multivibrator, on whose .109018 / 1490

20519 5 Ö

- ίο -

Input a differentiating circuit is connected, which consists of a capacitor 50 and a resistor 51. A diode 53 is connected to a connection node 52 between the capacitor 50 and the resistor 51, which is in turn connected to the collector of a normally non-conductive transistor 54. The diode 53 is in polarized in one direction, so that only negative impulses pass through. The collector of transistor 54 is Connected via a capacitor 55 to the base of a normally conductive transistor 56, whose collector via a resistor to the base of the normally non-conductive Transistor 54 is connected. The resistor 51 is connected to a bus line connected to a battery 58 connected. The collector of the normally non-conductive transistor 54 and the base and the The collectors of the normally conducting transistor 56 are connected to the bus 58 via resistors 59, 60 and 61 connected. The emitters of the two transistors 54 and 56 are connected directly to ground. The fuel cut signal is taken from the collector of the normally conducting transistor 56.

The operation of the locking signal generator 30 shown in Fig. 4 is such that when the throttle valve 10 returns to its fully closed position at the connection node 52 between the capacitor 50 and the

1Q9818 / U90

- 11 -

Resistor 51 has a negative voltage, the size of which is proportional to the speed of the throttle valve movement is. The negative voltage is applied through the diode 53 and the capacitor 55 to the base of the normally conducting transistor 56 is applied. Referring to FIGS. 5 (a), 5 (b) and 5 (c), the transistor 56 becomes non-conductive and thus the transistor 51 conductive when the Speed at which the throttle valve 10 returns to its fully closed position, a predetermined value which corresponds to the threshold voltage of transistor 56. The multivibrator is now in its quasi stable state and it generates a at the collector of the normally conductive transistor 56 Output signal. The circuit remains more or less stable in the State only for a limited duration T, which depends on the values of the capacitor 55 and the resistor 60. The duration T is set so long that the (

Collector of transistor 56 an output voltage remains until the throttle valve 10 is fully closed Position reached as it is in Fig. 5 (c) Dargesisllt. When the defined period ends, a regenerative one takes place Process that makes the transistor 56 conductive and, if necessary, the multivibrator in its initial stable state returns.

The output from the collector of transistor 56 109818/1490.

is supplied to a driver circuit with a resistor 6JJ ₁ and a normally non-conductive transistor 71 in the shut-off valve control device 31 according to FIG. When the fuel cut-off signal is applied to the base of the transistor 71, the latter becomes conductive, so that the cut-off valve 15 is closed in order to interrupt the fuel supply to the injection nozzle 14, λ

r ■

In the left part of FIG. 6 there is an input connection 72 of the circuit which is connected to the trigger device 32 (FIG. 1) driven by the motor, so that a _{pulse signal indicating the t} motor speed is applied to the circuit. According to the illustration, a differentiating circuit composed of a capacitor 73 and a resistor 74 is connected to the input connection 72. With the connection node between the capacitor 73 and the resistor 74 ψ is a diode 7.5 is connected, which is polarized in a direction that it passes only positive pulses. The diode 75 is also connected to an integrator, which has a resistor. 76 and a capacitor 77, the connection between these to the base of a. Transistor 78 is connected. Thus, a DC voltage proportional to the motor speed is applied to the base of transistor 78. The collector of transistor 78 is connected to a bus 79 through a resistor 80 while being . . 1 0 S Ö 1 8 / U 9 0 . ■,. ■ ■

Emitter is connected to ground via a resistor 81. The base of the transistor 78 is connected via a resistor 82 to a voltage divider which consists of two resistors 83 and 8k which are connected between the bus 79 and ground. The resistance values of the four resistors 81, 82, 83 and 84 are set so that when the base potential of the transistor 78 exceeds a λ value which corresponds to a first predetermined motor speed, for example 2000 rpm, the transistor becomes conductive.

The diode 75 is also connected to a further integrating circuit, which has a resistor 85 and a · Has capacitor 86, the connection between them being connected to the base of a transistor 87. As in the case of transistor 78, the collector of transistor 87 is connected to the bus line via a resistor 88 79 and its emitter through a resistor 89 Ground connected. The base of the transistor 87 is connected to a voltage divider via a resistor 90, which has two resistors 91 and 92. The four resistors 89, 90, 91 and 92 are set so that the transistor 87 becomes conductive when the potential at the base of this transistor rises to a value which corresponds to a second predetermined engine speed, e.g., 1000 rpm.

1 0 9 8 1 8 / U 9 ö

The collector of transistor 78 is connected to the collector of a normally non-conductive transistor via a capacitor 94 and a diode 95. The diode 95 is polarized in one direction so that it only allows a negative pulse to pass through. The collector of the transistor 9 3 is connected via a resistor 9 6 to the base of a normally conductive transistor 9 7 ψ ' which, together with the transistor 93, forms a flip-flop circuit. The base of the transistor. 93 is connected via a resistor 99 to the collector of the normally conductive transistor 9 7, this collector being the bus Vy via a resistor 100 ah

■ {■■

connected. The bases of the two transistors 93 and 97 are connected to ground via resistors 101 and 102, respectively. The emitters of the two transistors 9 3 and 97 are connected together via a parallel connection of a resistor stand 103 and a capacitor 104 to ground. The base of the normally conducting transistor 9 '/ is connected to the bus 79 via a diode 105 and two series-connected resistors 106 and 107. The switch 21 (Figs. 2 and 3) is connected to the connection between the two resistors 106 and 107, which is operationally associated with the throttle valve 10 such that it is closed when the throttle valve 10 reached their fully closed position. Of the

109618 / U9Ö

Switch 21 is also connected to ground. The collector of transistor 87 is connected to the base of the normally conductive transistor 97, through a capacitor 108 and a diode 109, which in is polarized in one direction, so that they only allow positive impulses to pass through. The usually leading one The collector of the transistor 97 of the flip-flop circuit is connected to the base of the via a resistor 110 Transistor 71 connected.

The above-described check valve control device operates in the following manner. If switch 21 held open, i.e. if the throttle valve 10 is not in its fully closed position, the Flip-flop circuit in its first stable state, at which the transistors 93 and 97 do not conduct or conduct, since the base of the transistor 97 via the resistors 106 { and 107 and the diode 105 is connected to the bus 79. When the transistor 97 is conductive Voltage at its collector applied to the base of transistor 71 is not sufficiently high enough, to make him lead. Thus, there is no current path from the manifold 79 through the solenoid operated check valve 15 manufactured to the mass. When the switch 21 is closed under these conditions, it becomes on negative going impulse at the connection between the 1Ö9818 / U3Ö

Resistors 106 and 107 generated, but not through the diode 105 is transferred to the base of the transistor 97.

If the engine speed rises above the second predetermined one Speed, e.g. looo rpm, the

^ Transistor 87 conductive and generated at its collector

** "■ has a negative going or negative pulse. However

the negative pulse has no effect on the flip-flop since the pulse is passed through the Diode 109 is prevented. If the engine speed continues to increase and exceeds the first predetermined one Speed, e.g. 2000 rpm, transistor 78 becomes conductive and develops a negative at its collector Pulse, which in turn via the capacitor 9 4 and the diode 95 to the collector of the normally non-conductive P transistor 93 and then through resistor 96 to the base

of the normally conducting transistor 9 7 is applied. When the throttle switch 91 is closed, power the negative pulse non-conductive transistor 97 and drives the flip-flop circuit in its second state, in which the increased voltage on the collector of the transistor 97 is applied to the base of the transistor 71, whereby this becomes conductive and the shut-off valve 15 is actuated.,

In contrast, if the engine speed falls to the

At the first predetermined rate, transistor 78 becomes non-conductive and generates a positive going or positive pulse at its collector. However, this pulse is prevented from passing through diode 95. If the motor speed continues to decrease to the second predetermined speed, transistor 87 becomes non-conductive and generates a positive pulse at its collector. The positive pulse can, however, go through the capacitor 108 and the diode 109 to the base of the transistor 9 7 and makes it conductive and possibly the transistor 9 3 non-conductive, so that the shut-off valve 15 stops interrupting the fuel supply to the injection nozzle 14. From the above description it follows that when the switch 21 is not closed, the flip-flop circuit remains in its first stable state, while the flip-flop circuit is under the influence of the output pulse from the transistors 78 and 87 when the switch 21 i

is not closed.

FIG. 7 shows an example of the fuel cut-off control device 43 according to FIG. 1, which can receive an injection pulse from the computer circuit 42 and amplify the signal in order to actuate the solenoid-operated injection valve 16. The injection pulse signal is applied to an input terminal 111 which-via a resistor

109818/1496

112 is connected to the base of a transistor 113. The collector of the transistor 113 is connected to a bus 115 via a resistor im, while its emitter is connected to ground. The collector is connected via a resistor 116 to the base of a transistor 117, the collector of which is connected via a resistor 118 to the bus line 115 and the emitter of which is connected to ground terminal Jk . The collector of transistor 117 is

connected to the base of a transistor 119, whose Emitter is connected to ground. The collector of the TransistOr 119 is via two series-connected resistors 120 and 121 connected to the bus 115, the connection between these resistors being connected to the base of a Transistor 122 is connected, the emitter of which is connected to the bus 115. The collector of the transistor

122 is across a capacitor 123 and a resistor 12H put to earth. It is a solenoid operated injection

■ ** valve 16 shown, which is the series connection of condenser

123 and resistor 124 bypass.

To the base of transistor 113 of the first ver- The gain stage is the collector of a transistor 125 on- • closed, the emitter of which is grounded. The base of transistor 125 is connected to the output terminal of the blocking signal generator 30 connected. In the absence of the

t SY1

Fuel cutoff signal at the base of transistor 125 this is kept non-conductive, so that an injection pulse generated by the computer circuit 42 is sent to the Base of transistor 113 is applied and through the transistor 113 and the following three transistors 117, 119 and 122 is amplified. The injection pulse amplified in this way actuates the injector 16 to dispense fuel into the intake manifold 12. If the fuel cut-off I signal is applied to transistor 125, this becomes conductive, so that the base potential of transistor 113 is zero falls off. As a result, the injection pulse signal applied to the circuit is interrupted, so that the injection valve 16 is not actuated.

8 (a) to 8 (e) show how the amount of carbon monoxide and hydrocarbons in the motor vehicle exhaust gases is reduced by using the fuel barrier device according to the invention. In FIGS. 8 (d) and 8 (c), the solid lines 126 and 127 represent the emission level of carbon monoxide and hydrocarbons as measured using the fuel cut-off device according to the invention, while the broken lines 128 and 129 represent those when the conventional fuel cut-off device is used indicate measured values.

9 schematically shows a further embodiment

the fuel cut-off device according to the invention in use in a carburetor system. Designated in the figure, ■ 130 a solenoid operated valve which open and close the idle and low speed passages 131 of the carburetor 132 can. The throttle valve 10 is attached to a throttle valve position detector 17 of the variable resistance type connected as shown in FIG. The sliding

™ contact 18 of the detector 17 is to a blocking signal generator 30 according to FIG. 4 connected. The output of generator 30 is to a check valve controller the type of Fig. 6 connected. The shut-off valve controller 31 also receives the engine speed indicating pulse signal from a trigger device 32 driven by the motor according to FIG. 1. The Output of the check valve control device 3l is to the solenoid operated check valve 130 connected so that

fe the valve 130 in response to the fuel lock halo is operated by the fuel cut signal generator 30, ' to close the passage through the idle and low-speed channel '131. The fuel cut-off device has also a switch 21 which is closed when the throttle valve 10 is in its fully closed position is moved. The throttle switch 21 is connected to the fuel cut controller 31. the How this locking device works depending on the engine speed and the movement of the throttle

flap switch 21 is the same as it in connection with FIG. 6 was explained.

109818/1490

Claims (13)

20519S9 Claims ί I./Fuel shut-off device for an internal combustion engine with a throttle valve and combustion cylinder, characterized by one of the throttle valve (10) associated first device (17), which is one of the throttle valve position corresponding signal generated by a P connected to the first device second device (30), which generates a fuel cut-off signal when the derivative of the voltage signal with respect to time is a predetermined Exceeds value, and by a third device (31) responsive to the fuel cutoff signal and cut off the fuel supply to the cylinders. 2. Device according to claim 1, characterized in that that the first device (17) is a throttle valve position ^ Detector with variable resistance (19) and a sliding contact (18) ^: which slides back and forth on a resistor (19) with the movement of the throttle valve (10). 3. The device according to claim 1, characterized in that the first device (17) is a throttle position detector of the oscillator type, which has an oscillator circuit (22, 23) with a constant oscillator frequency and a. DC / DC converter circuit (2 ¹ I, 26), which via a coupling β8pulβ (24) the output of the oscillator 109818 / 149Ö Circuit receives, the degree of coupling of the clutch coil is changed by a shielding plate '(25), the moves with the throttle valve (10). 4. Apparatus according to claim Ibis 3, characterized in that that the second device (30) is a fuel blocking signal generator which has a monostable Multivibrator with a differentiating circuit (50, 51) connected to its input. 5. Apparatus according to claim 1 to 1, characterized in that that the period of time during which the monostable multivibrator is in its quasi-stable state is like this is long that it lasts until the throttle valve is in the fully closed position. 6. Apparatus according to claim 1 to 5, characterized | by a throttle switch (21) that is closed will when the throttle is in its fully closed Position is brought. 7. Apparatus according to claim 1 to 6, characterized in that that the third device is a check valve control device (31) which is a flip-flop circuit (97, 93) and one connected to the second device 1O9818 / U90 Driver circuit for generating a fuel cut-off signal comprises, wherein the input of the shut-off valve control device to the throttle valve switch (21) and the Output of the lock valve control device is connected to a lock valve (16) which, when actuated, the Fuel supply to the injection nozzles (1Ό blocks. 8. Apparatus according to claim 1 to 7, characterized by a motor-driven trigger device (32) connected to the shut-off valve control device (31) for generating a signal indicative of the engine speed is connected to be applied to the shut-off valve control device is. 9. Apparatus according to claim 1 to 8, characterized in that that when the throttle valve switch (21) is closed, the shut-off valve control device (31) is at Rise in engine speed to a first predetermined value operates in such a way that the shut-off valve (16) is closed. 10. The device according to claim 9, characterized in that that the first predetermined value is 2000 rpm. 11. Device according to claim 1 to 9, characterized in that 1 0 9 8 1 8 / U 9 Ö indicates that when the throttle valve switch (21) is closed, the shut-off valve control device (31) is at. If the engine speed drops to a second predetermined value, it works in such a way that the shut-off valve (16) is opened. 12. Device according to claim 11, characterized marked A is characterized in that the second predetermined value is 1000 rpm. 13. The device according to claim 1 to 12, characterized by a fourth device (42) for calculating correct 'pulse widths of the injection pulses as a function of the engine speed, engine temperature and intake line pressure and by a fifth device for the Recording of the injection pulse and for de-energizing a Injection pulse booster circuit when the fuel cut signal is applied by the second device. Ik, device according to Claim 1, characterized by a shut-off valve (130) which is assigned to a carburetor (132) in such a way that it closes the idle and slow-speed duct (131) of the carburetor when the fuel shut-off signal is applied to the shut-off valve. 109818/1490 blank page