JPH0214537B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine fuel supply device that detects the exhaust smoke concentration of an engine such as a diesel engine and automatically controls the amount of fuel supplied to the engine.

In general, an engine's fuel supply system is adjusted to supply the engine with a predetermined amount of fuel depending on engine operating conditions such as intake air amount and engine rotational speed so that the engine operates most efficiently. , in actual use,
Due to poor maintenance of the fuel supply system itself or the engine, control of the fuel supply amount may deviate from the normal state, resulting in inappropriate exhaust smoke concentration.

For this reason, the engine fuel injection amount automatic control device of Utility Model Application Publication No. 119811/1983 is designed to:
The system detects changes in engine exhaust smoke concentration and prevents more fuel than necessary from being supplied to the engine, improving fuel consumption and exhaust smoke concentration.

On the other hand, some diesel engines in particular are equipped with an exhaust brake that closes off a valve in the engine's exhaust pipe to operate and control the engine as a compressor. There is a tendency for the exhaust smoke concentration to temporarily increase when the system is released. At this time, if the fuel injection amount is controlled based on the exhaust smoke concentration as in the above-mentioned Utility Model Application Publication No. 50-119811, the amount of fuel supplied will decrease relative to the engine load when accelerating after releasing the exhaust brake. Therefore, a problem arises in that the necessary engine output cannot be obtained.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel supply device that can supply fuel to an engine so that sufficient engine output can be obtained when the exhaust brake is released.

The present invention provides a main control system that appropriately controls the amount of fuel supplied to the engine depending on the operating state, an exhaust smoke concentration detector that detects the exhaust smoke concentration, and an exhaust gas detected by the exhaust smoke concentration detector. A control circuit that compares the smoke concentration with a set exhaust smoke concentration predetermined according to the operating state and outputs a difference signal, and according to this difference signal, makes the engine exhaust smoke concentration equal to or less than the set exhaust smoke concentration. In an engine fuel supply system that includes a sub-control system consisting of an actuator that corrects the amount of fuel supplied, the system detects that the exhaust control valve that controls the opening and closing of the exhaust passage of the engine changes from a closed state to an open state. , a valve state detector that outputs a detection signal, an operation signal generator that receives this detection signal and outputs an operation signal for a predetermined time from the time of input of this detection signal, and receives this operation signal and operates the control circuit. The present invention is characterized by being provided with an adjustment device that controls to increase the value of the set exhaust smoke concentration or to stop the operation of the sub-control system.

According to the engine fuel supply device of the present invention having the above-described structure, the release of the exhaust brake is detected by detecting that the exhaust control valve changes from the closed state to the open state, and at this time, the above-mentioned secondary Since the control system is controlled to increase the set exhaust smoke concentration value or to stop the operation of this sub-control system, the necessary amount of fuel is supplied to the engine when the exhaust brake is released. Therefore, sufficient engine output can be obtained during acceleration, for example, following release of the exhaust brake.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An engine fuel supply system according to a preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a fuel supply system for a diesel engine 1 equipped with a distributed fuel injection pump A, and in this figure, reference numeral 2 indicates an intake passage, and reference numeral 3 indicates an exhaust passage. The exhaust passage 3 is provided with an exhaust control valve 4 that acts as an exhaust brake.
The opening and closing of the exhaust control valve 4 is controlled by a diaphragm actuator 5, and the negative pressure chamber 5a of the actuator 5 is
Vacuum tank 7 and vacuum pump 8 via passage 6
is communicated with. This passage 6 is provided with a solenoid valve 9 for controlling the introduction of negative pressure from the vacuum tank 7 into the negative pressure chamber 5a of the actuator 5. This solenoid valve 9 is a foot brake switch.
SW ₁ (on state when stepping on the brake) and engine speed is the specified speed (e.g. 1500 rpm)
It is designed to be controlled by a rotary switch _SW2 which is turned on in the above cases. The solenoid valve 9 is
When the switches SW ₁ and SW ₂ are turned on, they open to introduce negative pressure into the negative pressure chamber 5a of the actuator 5, and close the valve 4 to act as an exhaust brake.

The distribution fuel injection pump A has a housing 10, and inside the housing 10, a pump chamber 11 to which fuel is supplied and a cylindrical hole 11a communicating with the pump chamber 11 are formed. A plunger 12 is disposed within the cylindrical hole 11a and distributes and pressure-feeds the fuel within the pump chamber 11 by rotating and reciprocating. A cam disk 13 is integrally fixed to one end of this plunger 12, and this cam disk 13 is
The plunger 12 and the plunger 12 are rotated by a drive shaft 14 at a speed that is one-half of the engine speed.

The cam disk 13 is provided with the same number of face cams 13a as the number of cylinders of the engine, and the cam disk 13 is brought into pressure contact with the plunger 12 and the roller 15 whose position is fixed by a plunger spring (not shown). It is energized as follows. In this way, the cam disc 13 has the face cam 13a attached to the fixed roller 15.
The plunger 12 is rotated in a state in which it is in pressure contact with the plunger 12 to cause the plunger 12 to reciprocate by the amount of cam lift. The plunger 12 has a suction slit 12a communicating with the suction port 16 of the housing 10, a central oil passage 12b, a distribution slit 12c communicating with the discharge passage 17 of the housing 10, and a cut-off port 12d opening into the pump chamber 11. A cut-off sleeve 18 for opening and closing the cut-off port 12d is slidably fitted around the outer periphery of the plunger 12. The plunger 12 opens the suction slit 12 when retracting.
By matching a with the suction port 16, the fuel in the pump chamber 11 fed from the tank is sucked into the chamber 19 at the tip, and then, as the plunger 12 rotates and moves forward, the suction port 16 closes and is simultaneously compressed. When the distribution slit 12c and the discharge passage 17 match, the compressed high-pressure fuel is injected into the combustion chamber of a predetermined cylinder via the delivery valve 20,
Subsequently, when the plunger 12 moves further forward, the cut-off port 12d moves into the cut-off sleeve 18.
By moving to the side and opening, the high-pressure fuel inside the plunger 12 is released into the pump chamber 11, its pressure is reduced, and the injection is completed.
This reciprocating movement of the plunger 12
During one rotation of the plunger 12, the number of cylinders is
The fuel is sequentially injected into each cylinder through discharge passages 17 (only one is shown) provided at equal intervals around the outer periphery of the cylinder. Further, the fuel injection amount is increased or decreased by sliding the cut-off sleeve 18 and changing the effective stroke amount of the plunger 12, that is, by adjusting the opening timing of the cut-off port 12d. When moving to the left in the figure, the injection amount decreases, and conversely, when moving to the right, the injection amount increases.

A half-all speed governor 21 is built in the upper part of the pump chamber 11.
This is to adjust the movement of the cut-off sleeve 18 in accordance with the engine speed to adjust the fuel injection amount. Governor 21 is governor shaft 2
The governor shaft 22 rotatably supports a governor gear 24 that meshes with a drive gear 23 fixed to the drive shaft 14. A flyweight holder 26 that is integrally formed with the governor gear 24 has a flyweight 25 incorporated therein. A governor sleeve 27 is slidably fitted into the governor shaft 22, and the governor sleeve 27 is moved around the governor shaft 22 by the expanding operation of the flyweight 25 due to centrifugal force.
It is configured to slide along the

A telesion lever 28 is in contact with the tip of the governor sleeve 27 , and a start lever 29 is disposed adjacent to the telesion lever 28 . It is pivotally supported by a common first pin 31 fixed to. At the bottom of the start lever 29 is a ball head pin 3.
2 is implanted, and this ball head pin 32 is configured to engage with the pin hole 18a of the cut-off sleeve 18 and move the cut-off sleeve 18 in response to rotation of the start lever 29. A start spring 33 is mounted between the start lever 29 and the tension lever 28.

The housing 10 includes a control lever 34.
is pivotally supported via a shaft 35, and this control lever 34 is connected to a cable or link 3.
6, etc., to the accelerator pedal 37. One end of a yoke 39 is attached to the inner end of the shaft 35 via an eccentric pin 38.
At the other end of this yoke 39, there is an idle pin 4 extending through the upper end of the telesion lever 28.
0 is connected, and the head 4 of this idle pin 40
An idle spring 41 is arranged between Oa and the tension lever 28. Yoke 39 has
Two compression springs, a governor spring 42 and a partial load spring 43, are installed with a predetermined load.
As the angle of the control lever 34 increases, that is, the amount of depression of the accelerator pedal 37 increases, the yoke 39 is pulled to the left in the figure, and the tension lever 28 is moved to the left by the increased tension. It acts to pull on. Note that the collector lever 30 is fixed to the housing 10 by a second pin 44,
It is biased by a lower support spring 45, and its rotational position is adjusted by a full load adjustment screw 46.

Reference numeral 51 denotes a maximum injection amount regulating device that regulates the amount of movement (rotation amount) of the tension lever 28, which constitutes the fuel control member of the fuel injection pump A, in the fuel increase direction. Negative pressure chamber 53 defined by diaphragm 52
have. This negative pressure chamber 53 communicates with a passage 54, and a spring 55 is compressed in this negative pressure chamber 53. An actuation rod 56 is connected to the diaphragm 52 and has an engaging portion 56a consisting of a small diameter portion and a large diameter portion formed below the small diameter portion. One end 57a of a regulating lever 57 rotatably supported on the housing 10 by a pin 58 is engaged with the engaging portion 56a of the actuating rod 56, and the other end 57b of the regulating lever 57 is engaged with the engaging portion 56a of the operating rod 56. Direction of fuel increase of the fuel lever 28 (counterclockwise in the figure)
the tension lever 28 so as to restrict rotation of the tension lever 28;
It is in contact with the upper end of. A vacuum pump 59 is connected to the passage 54, and a solenoid valve 60 is provided. By controlling the opening and closing of the solenoid valve 60, the pressure inside the negative pressure chamber 53 is adjusted to achieve maximum injection. Adjust amount.

The solenoid valve 60 is connected to a control circuit 61 that controls opening and closing of the solenoid valve. This control circuit 6
1 is equipped with a comparator 62, and this comparator 62
A reference voltage generator 63 indicating the set exhaust smoke concentration is connected to one input terminal 62a of the exhaust gas.

The exhaust passage 3 is provided with an exhaust smoke concentration detector 64 that detects the exhaust smoke concentration of the exhaust gas flowing through the exhaust passage 3 and outputs an electric signal indicating this concentration. The output terminal is connected to the other input terminal 62b of the comparator 62. The exhaust smoke concentration detector 64 optically detects the exhaust gas concentration as shown in FIG. There is. Light emitting part 65
consists of a light emitting diode 65a as a light source and a collimator lens 65b, a phototransistor 66a that receives the light from the light emitting section 65 that has passed through the exhaust gas, and converts it into an amount of electricity; This phototransistor 66
a lens 66b for converging on the phototransistor 66a, and an amplifier 66c for amplifying the output of the phototransistor 66a.
It is made up of

In the above configuration, when the exhaust smoke concentration is less than or equal to the set exhaust smoke concentration, the control circuit 61 does not output a control signal, and therefore the solenoid valve 60 is in a closed state. When the solenoid valve 60 is in the closed state like this,
Since negative pressure does not act on the negative pressure chamber 53 and it is opened to the atmosphere, the diaphragm 52 is biased downward by the spring 55, the actuating rod 56 is lowered, and the regulating lever 57 is accordingly moved clockwise in the figure. The small diameter engaging portion 5 of the actuating rod 56 is rotated to
6a, one end 57a of the regulation lever 57 is placed in a retracted position where it does not impede the rotation of the tension lever 28 in the direction of fuel increase, and thus the rotation restriction of the tension lever 28 is released and the fuel injection pump A is moved. From this point onward, the maximum amount of fuel to be injected is supplied. On the other hand, when the exhaust smoke concentration exceeds the set exhaust smoke concentration, the output of the exhaust smoke concentration detector 64 becomes smaller than the reference voltage, so the comparator 62
outputs a control signal to open the solenoid valve 60. When the solenoid valve 60 opens in this way, negative pressure acts on the negative pressure chamber 53, biasing the diaphragm 52 upward against the spring force of the spring 55, and the actuating rod 56 rises accordingly, thereby regulating the pressure. The lever 57 comes into contact with the large-diameter engagement portion 56a of the actuating rod 56, and the regulating lever 57 is rotated counterclockwise in the figure to be positioned at the regulating position where the rotation of the tension lever 28 in the fuel increasing direction is restricted. Therefore, by regulating the rotation of the tension lever 28, the maximum fuel injection amount of the fuel injection pump A is reduced and regulated.

As described above, the maximum fuel injection amount of the fuel injection pump A is controlled according to the engine operating condition to achieve an appropriate exhaust smoke concentration, but generally the exhaust smoke concentration is determined by the release of the exhaust brake. In other words, when the exhaust control valve 4 changes from the closed state to the open state, there is a tendency for the fuel injection amount to increase temporarily, and if the fuel injection amount is controlled based on the exhaust smoke concentration at this time, the exhaust smoke concentration will be reduced. However, if this is done, the engine output becomes insufficient compared to the required engine output, especially when transitioning from a deceleration state to an acceleration state, impairing drivability. Therefore, in one embodiment of the present invention, the reference voltage generator 63 is
An adjustment device 67 is provided to adjust the reference voltage generated by the reference voltage. This adjustment device 67 is connected to the generator 63
Reference value correction circuit 68 that increases the reference voltage of
When switches SW ₁ and SW ₂ are opened, that is, when the exhaust brake is released,
and an operation signal generation circuit 69 that outputs an operation signal for operating the reference value correction circuit 68 for a predetermined period of time. The reference value correction circuit 68 receives the operation signal output from the operation signal generation circuit 69 and operates to increase the reference value, that is, the set exhaust smoke concentration, for a predetermined period of time after the exhaust brake is released.

In the above embodiments, a type of adjustment device that increases the reference value, that is, a set exhaust smoke concentration has been described, but there is also a type of adjustment device that stops the control system that controls the fuel injection amount based on the exhaust smoke concentration. Good too. In this example, the third
As shown in the figure, a switch 70 is provided between the solenoid valve 60 and the control circuit 61, and the opening and closing of this switch 70 is controlled by an adjustment device 67'. This adjustment device 67'
includes an operation signal generation circuit 69 similar to the adjustment device 67, and the switch 7 while this operation signal generation circuit 69 generates an operation signal in the same manner as above.
It consists of a switch controller 71 that opens 0. When the switch controller 71 operates and the switch 70 is opened, the output of the control circuit 61 does not reach the solenoid valve 60, so the solenoid valve 60 remains closed regardless of the output state of the control circuit 61. maintained. Therefore, the fuel supply amount is not controlled in accordance with the exhaust smoke concentration.

FIG. 4 shows an example in which the fuel supply amount control device of the present invention is applied to a diesel engine equipped with an in-line fuel injection pump B having a plunger for each cylinder. The description thereof will be omitted. In FIG. 4, reference numeral 80 is a fuel injection pump main body, and reference numeral 81 is a fuel control rack disposed within the pump main body 80. One end of this fuel control rack 81 is connected to the governor 21.
It is connected to an accelerator pedal 37 via a link mechanism and a control lever 34. Reference numeral 82 denotes a maximum injection amount regulating device that is disposed opposite the other end of the fuel control rack 81 and regulates the amount of movement of the fuel control rack 81 in the fuel increase direction (leftward in the figure). This maximum injection amount regulating device 8
2 includes a solenoid 83 that operates in response to a control signal from the control circuit 61, and one end of which is connected to the solenoid 8.
3, the other end of which abuts the other end of the fuel control rack 81, and a regulation lever 84 that rotates to a regulation position that regulates movement of the fuel control rack 81 in the fuel increase direction by the operation of the solenoid 83. , the regulation lever 84 is activated by the operation of the solenoid 83.
is rotated to the regulating position to regulate the movement of the fuel control rack 81 in the direction of increasing the amount of fuel, thereby regulating the maximum fuel injection amount to decrease. In addition, the code 85
is a maximum movement adjustment screw that adjusts the maximum movement of the fuel control rack 81 in the fuel increase direction via the regulation lever 84.

Therefore, in this embodiment as well, when the exhaust smoke concentration increases, the amount of movement of the fuel control rack 61 in the direction of fuel increase is regulated, the maximum fuel injection amount is regulated to decrease, and the amount of fuel is reduced to a predetermined value from the time the exhaust brake is released. The time adjusting device 67 increases the set exhaust smoke concentration, thereby supplying a sufficient amount of fuel to the engine to obtain the required engine power. It goes without saying that the control system shown in FIG. 3 may also be applied to this in-line fuel injection pump B. Furthermore, although the most convenient type of operation signal generation circuit 69 is a timer, it is not limited to this, and various circuits can be used, such as a circuit that detects the rotational state of the engine and outputs an operation signal for a predetermined period of time. Conceivable.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a fuel supply system for a diesel engine equipped with a distributed fuel injection pump according to an embodiment of the present invention, and FIG. 2 is a diagram showing exhaust smoke concentration detection used in the fuel supply system of FIG. 1. FIG. 3 is a schematic diagram showing the adjustment device, and FIG. 4 is a diagram showing a modified example of the adjustment device.
The figure is a configuration diagram showing an example in which the fuel supply device of the present invention is applied to a row-type fuel injection pump. A, B... Fuel injection pump, 1... Diesel engine, 3... Exhaust passage, 4... Exhaust control valve,
51... Maximum injection amount control device, 61... Control circuit, 63... Reference voltage generator, 64... Exhaust concentration detector, 67... Adjustment device, 68... Reference value correction circuit, 69... Operation signal generation circuit.

Claims (1)

[Claims] 1. A main control system that appropriately controls the amount of fuel supplied to the engine according to the operating condition, an exhaust smoke concentration detector that detects the exhaust smoke concentration, and the exhaust smoke concentration detected by the exhaust smoke concentration detector and the operating condition. a control circuit that compares the exhaust smoke concentration with a predetermined set exhaust smoke concentration and outputs a difference signal; In an engine fuel supply system that is equipped with a sub-control system consisting of an actuator that corrects the amount of fuel, it detects that the exhaust control valve that controls the opening and closing of the engine's exhaust passage changes from a closed state to an open state and outputs a detection signal. an operating signal generator that inputs the detection signal and outputs an operating signal for a predetermined period of time from the time when the detection signal is input; 1. A fuel supply system for an engine, comprising: an adjustment device that controls the sub-control system to increase the fuel value or to stop the operation of the sub-control system.