JPH0519020B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel supply control device, and in particular, includes an actuator that regulates the maximum stroke of a control rack of a fuel injection pump, and an electronic control device that controls the supply of working fluid to the actuator. The present invention relates to a control device for controlling.

A diesel engine is equipped with a fuel injection pump, which supplies fuel by sequentially injecting fuel into each cylinder of the engine. This fuel supply is controlled by a mechanical governor attached to the fuel injection pump. The highest and lowest mechanical governors that have been used in the past are limited to the normal rotation range (approximately 900 rpm
(above), if the engine speed falls below the set value given by the load lever, the amount of fuel supplied is increased, and if it rises above the set value, the amount of fuel supplied is decreased. It does not have a speed regulating function. Therefore, it has not been possible for a vehicle equipped with a diesel engine to run economically or at a constant speed using such a conventional mechanical governor.

Therefore, attempts have been made to provide an actuator that regulates the maximum stroke of the control rack of the fuel injection pump, and to control the supply of working fluid to this actuator using an electronic control device. By adding such a structure to the fuel injection pump, economical driving is possible by regulating the maximum stroke of the control rack to a certain value, and the actuator controls the control rack in preference to mechanical governor control. By controlling this, it becomes possible to drive the vehicle at a constant speed. However, the actuator must be configured to control the control rack in preference to the mechanical governor, and for this reason, for example, if the supply of working fluid is cut off, the actuator will not move in the direction that regulates the stroke of the control rack. If the engine is operated in reverse, the fuel supply to the engine will be stopped and the vehicle will no longer be able to run, and even if you try to start the vehicle without working fluid being supplied, the fuel supply to the engine will be interrupted. If this is not done, the engine will not start, resulting in the inconvenience.

The present invention has been made with the aim of overcoming these problems, and provides a method for controlling the maximum stroke of the control rack while eliminating the influence on the mechanical governor caused by the regulation by the fluid actuator. If the supply of working fluid is cut off, this actuator operates in the direction of releasing the regulation of the control rack, so that the engine continues to rotate even if the supply of working fluid is cut off. The object of the present invention is to provide a device capable of starting an engine.

The present invention will be described below with reference to an illustrated embodiment. FIG. 1 shows a diesel engine 1 equipped with a fuel supply control device according to the present embodiment, and a fuel injection pump 2 is installed on the side of the engine 1. It is provided. The fuel injection pump 2 is driven by the rotation of the engine 1 via a gear 3, a timer 4, and a camshaft 5. That is, the injection pump 2 includes the engine 1
The same number of pump units 6 as the number of cylinders are provided, and each plunger of these pump units 6 is sequentially driven by a cam fixed to the camshaft 5. Each pump unit 6 is connected to a corresponding cylinder by a fuel supply pipe 7.
Fuel is supplied to the engine 1 via the fuel tank.

The fuel injection pump 2 is provided with a control rack 8.
Accordingly, the amount of fuel supplied by each pump unit 6 at one time is controlled. The control rack 8 is controlled by a mechanical governor 9 attached to the fuel injection pump 2. A load lever 10 is rotatably provided on the side surface of the mechanical governor 9, and this lever 10 is connected to an accelerator pedal 12 via a wire cable 11. Therefore, the amount of rotation of the accelerator pedal 12 is controlled by the load lever 10 via the wire cable 11.
Further, the amount of rotation of the load lever 10 is transmitted to a control rack 8 via a mechanical governor 9, and the control rack 8 controls the amount of fuel supplied.

An air actuator 13 is also attached to the mechanical governor 9, and this actuator 13 is connected to an air tank 14 via a solenoid valve 15. Further, air is exhausted from the air actuator 13 by a solenoid valve 16. Furthermore, the air tank 14
is connected to the air actuator 18 via the solenoid valve 17.
It is connected to the. This actuator 18 is
When the rod is pushed out, the load lever 10 is rotated to the maximum rotation position. Each of the electromagnetic valves 15, 16, and 17 is controlled by a control signal from a microcomputer 19, respectively. The microcomputer 19 includes a rotation detection sensor 20 for detecting the engine rotation speed, a temperature sensor 21 for detecting the temperature of engine oil, a temperature sensor 22 for detecting the temperature of the engine cooling water, and a temperature sensor 22 for detecting the position of the control rack 8. The detection outputs of a position detection sensor 23 that detects the position of the rod of the air actuator 13 and a position detection sensor 24 that detects the position of the rod of the air actuator 13 are supplied. In addition to this, various information is also supplied to the microcomputer 19, such as the gear ratio of the transmission, the traveling speed of the vehicle, whether or not the brakes are activated, and the outside temperature.

Next, the structure of the air actuator 13 will be described. As shown in FIGS. 2 and 3, the air actuator 13 is composed of an air cylinder, and this air cylinder is equipped with a piston 25. The piston 25 is constructed by stacking a pair of disc-shaped plates, and a return spring 26 is interposed above the piston 25. Further, a seal ring 40 is attached to this piston 25, and this seal ring 40 prevents air from leaking. A port 42 is formed in the base 41 of the air actuator 13, and the air actuator 13 is connected to the solenoid valves 15 and 16 by an air supply pipe 43 connected to the port 42. ing. Further, a small hole 44 communicating with the outside is formed on the upper side of the air actuator 13.
An air filter 45 is attached to the upper end. Further, a rod 27 is fixed to the piston 25, and this rod 27 passes through a through hole 46 formed in the port 42. A bush 47 is interposed between the through hole 46 and the rod 27. Further, a seal ring 48 is attached to the upper part of the bush 47.

The rod 27 of the air actuator 13 extends downward and is inserted into the casing of the mechanical governor 9. And this rod 2
A pin 28 is implanted at the lower end of 7. A stop lever 29, which can come into contact with this pin 28 at one end, is attached to the pin 3 on the casing of the mechanical governor 9.
It is rotatably supported via 0. The other end of this stop lever 29 is connected to the control rack 8.
It is adapted to come into contact with a protruding piece 31 provided on. The control rack 8 is connected via a rod 32 and a sleeve 33 to a floating lever 34 that constitutes the output end of the mechanical governor 9.
is connected to. A protrusion 35 formed on the rod 32 engages with a slit-like elongated hole 36 formed on the sleeve 33, allowing relative axial movement between the two. Further, a compression coil spring 37 is interposed in the sleeve 33, and this spring 37 causes the rod 32 to move to the second position.
To the left in Figures and Figure 3 (direction of increase in fuel)
is urged to move toward.

In the above configuration, when the solenoid valve 16 is opened by a control signal from the microcomputer 19 and the air inside the actuator 13 is discharged,
The piston 25 shown in FIGS. 2 and 3 is moved downward by the return spring 26, and the rod 27 is accordingly moved downward. Therefore, if the rod 27 is moved sufficiently downward, the stop lever 29 can be rotated to the position shown by the dashed line in FIG. 2 without interfering with the movement of the control rack 8. In such a state, the projection 35 of the rod 32 is pushed against the sleeve 3 by the action of the compression coil spring 37.
In this state, the relative position between the rod 32 and the sleeve 33 is maintained constant. That is, in this case, the rod 32 and floating lever 34 operate in the same way as if they were directly connected. Therefore, when the accelerator pedal 12 is depressed and the load lever 10 is rotated by the wire cable 11, the rotation of the load lever 10 is transmitted to the control rack 8 via the mechanical governor 9, which is different from the conventional method. Fuel supply is controlled in the same way as a mechanical governor.

Next, to explain the operation when performing economical driving using this engine, the solenoid valve 15 is opened based on instructions from the microcomputer 19, and air is introduced into the actuator 13.
5 from the air tank 14. The piston 25 is then pushed against the return spring 26 and moves upward in FIG. As the piston 25 moves upward, the rod 2
7 also moves upward, and as a result, the stop lever 29, whose rotation is restricted by the pin 28 of the rod 27, rotates to the position shown, for example, by a solid line in FIG. By adjusting the amount of air in the air actuator 13 so that the rod 27 is at a predetermined position in this way, the movement stroke of the rack 8 to the left is regulated by the stop lever 29. As a result, the rack 8 cannot be moved to its maximum travel stroke.

Therefore, as shown by the chain line in FIG. 4, the ratio of the fuel supply amount to the engine speed is suppressed to a value lower than the maximum supply amount shown by the solid line in the same figure. Then, by controlling the solenoid valves 15 and 16 by the microcomputer 19 and further returning the position of the rod 27 by the actuator 13, the amount of fuel supplied is further reduced as shown by the dotted line in FIG. I can do it. Therefore, by using this actuator 13 and the stop lever 29 driven by the actuator 13 to regulate the maximum travel stroke of the rack 8, economical travel can be achieved and fuel consumption can be reduced. . Furthermore, when the maximum stroke of the rack 8 is regulated using the actuator 13 in this way, the output torque of the engine with respect to the engine speed changes from the state shown by the solid line to the state shown by the chain line, and then to the state shown by the dotted line, as shown in FIG. will change to the state of Note that Figures 4 and 5 correspond,
When the amount of fuel supplied is shown by the dotted line in FIG. 4, the output torque as shown by the dotted line in FIG. 5 is obtained, and the amount of fuel supplied is decreased as shown by the dotted line in FIG. In this case, the engine output will be as shown by the dotted line in FIG.

In addition, in the case of the above-mentioned economy running, even if the floating lever 34 of the governor 9 shown in FIG. This will be absorbed by the relative movement between sleeve 33 and rod 32. That is, as the compression coil spring 37 contracts and the rod 32 is inserted relatively into the sleeve 33, rotation of the floating lever 34 exceeding a predetermined amount is absorbed.

Next, when this engine is used to drive at a constant speed, first the solenoid valve 17 is opened by the microcomputer 19, and compressed air is supplied from the air tank 14 to the actuator 18 through the solenoid valve 17. Then, the piston rod of the actuator 18 is pushed out, and the load lever 10 is rotated to the maximum rotational position in the direction of increasing fuel, that is, in the counterclockwise direction about the pin 38 in FIG. 2, regardless of the amount of depression of the accelerator pedal 12. That will happen. Therefore, the rotation of the load lever 10 is transmitted to the sleeve 33 via the floating lever 34 of the governor 9, and the compression coil spring 37 pushes the rod 32. In other words, the control rack 8 is pushed in the direction of increasing fuel. Therefore, in this state, the microcomputer 19 controls the solenoid valves 15 and 16.
It is possible to control the amount of fuel supplied by controlling the air actuator 13 via the rod 27 and the stop lever 29 and arbitrarily restricting the movement of the control rack 8 to the left in FIG. become. Therefore, the engine speed,
The vehicle can run at a constant speed by controlling the control rack 8 with high precision based on control signals from the microcomputer 19 into which information such as the vehicle's running speed is input. In this case as well, the relative movement between the rod 32 and the floating lever 34 is caused by the movement between the sleeve 33 and the rod 3.
2, and the compression coil spring 37 only deforms at this time. Therefore, the conventional mechanical governor 9 is provided with air actuators 13, 18 and a stop lever 29,
This allows the vehicle to travel at a constant speed by regulating the amount of movement of the control rack 8.

Further, the amount of movement of the control rack 8 is regulated by bringing a stop lever 29 whose swing is controlled by the air actuator 13 into contact with a protrusion 31 provided on the control rack 8. Therefore, even if the air actuator 13 is configured with an air cylinder in which delicate position control is difficult, the control accuracy of the control rack 8 can be increased by appropriately setting the lever ratio of the stop lever 29.

Next, the operation when air is no longer supplied to the actuator 13 from the air tank 14 will be described. i.e. compressor or air tank 1
If any abnormality occurs in the compressed air supply device 4 or the like, compressed air will not be supplied to the air actuator 13 even if the solenoid valve 15 is opened, or The air pressure drops below the operating pressure. Therefore, in this case, even if the microcomputer 19 supplies a control signal to the solenoid valve 15,
Actuator 13 will not operate correctly. The piston 25 of the actuator 13 is then moved back downward by the return spring 26. Therefore, together with this piston 25, the rod 27
will also move downward. Therefore, the stop lever 29 is in a state where it can freely rotate, and the restriction on the maximum stroke of the control rack 8 by the stop lever 29 is released.
That is, when the actuator 13 is no longer operated correctly, the rod 27 is moved back by the return spring 26, and the stop lever 29 is swung back to the outside of the locus of movement of the protrusion 31 and interferes with the control rack 8. Therefore, the restriction on the maximum stroke of the control rack 8 is released. Therefore, in this case, it is the same as if the actuator 13 and stop lever 29 were not present, and the control rack 8 is controlled by the mechanical governor 9, making it possible to continue normal running. Furthermore, when the supply of working fluid, that is, compressed air, to the actuator 13 is cut off, the control rack 8 can move freely, so the engine can be started while operating the throttle button.
This makes it possible to supply the engine with sufficient fuel.

Next, a modification of the above embodiment will be explained with reference to FIG. In this modification, parts corresponding to those in the above embodiment are given the same reference numerals, and descriptions of parts having the same structure will be omitted. The actuator 13 according to this modification includes a bellows 51 made of rubber, and the bellows 51 communicates with the air supply pipe 43 via a port 42 formed in the base 41 of the actuator 13. The lower end of the bellows 51 is fixed to the base 41, and the upper end of the bellows 51 is fixed to the spring receiver 52. A return spring 26 is interposed between the spring receiver 52 and the upper part of the casing of the air actuator 13. And this air actuator 1 is attached to the spring receiver 52.
No. 3 rod 27 is fixed.

Therefore, based on instructions from the microcomputer 19, the solenoid valves 15 and 16 are opened and closed to control the air pressure in the bellows 51 of the actuator 13, thereby controlling the maximum stroke of the control rack 8 via the rod 27 and the stop lever 29. By regulating this, it becomes possible to perform economical driving or constant speed driving in the same manner as in the above embodiment. When the air supply to the bellows 51 of the actuator 13 is cut off, the return spring 26 moves the rod 27 downward via the spring receiver 52, thereby changing the stroke of the control rack 8. Restrictions will be lifted. Therefore, if an abnormality occurs in the compressed air supply system, the governor 9 allows normal running, and the engine can be started even if compressed air is not supplied to the actuator 13. become. Moreover, since the actuator 13 is equipped with a bellows 51 instead of an air cylinder, the actuator 1
There is no need for a seal ring or the like for sealing 3, thereby simplifying the structure.

Next, another modification will be explained with reference to FIG. In this modification, a metal bellows 55 is used, and the upper end of this bellows 55 is connected to the rod 27 via a mounting plate 56. Further, the lower end of the bellows 55 is attached to the base 41 and communicates with the port 42 of the base 41. The metal bellows 55 itself is constantly trying to contract, so by supplying compressed air against the contracting force of the bellows 55, the rod 27 is moved upward. Therefore, if the air supply is cut off, the bellows 5
The rod 27 is moved downward by the restoring force of the rod 5 itself, and the restriction of the control rack 8 by the stop lever 29 is released. Also in this modification, by controlling the supply of compressed air into the bellows 55, the maximum stroke of the control rack 8 can be regulated to perform economy travel or constant speed travel, as described above. Similar to the example. Furthermore, since the metal bellows 55 is used, there is an advantage that a return spring can be omitted.

As is clear from the above description, according to the present invention, since the maximum stroke of the control rack is regulated using the stop lever whose swing is controlled by the air actuator, delicate position control is difficult. Even when the air actuator is configured with an air cylinder, the control accuracy of the control rack can be increased by appropriately setting the lever ratio of the stop lever, and the air supply to the air actuator can be interrupted. If the stop lever falls down, the return spring swings and retracts the stop lever to a position where it does not interfere with the control rack. Therefore, in the event of an emergency where the air pressure has decreased, normal control by the mechanical governor is performed, making it possible to avoid an unexpected situation where the engine stops. In addition, since the actuator is configured with an air actuator, the reliability of the fuel supply system can be increased, and the pressure of the fuel supply to the fuel injection pump will not change unexpectedly due to the operation of the air actuator. There's nothing to do.

Furthermore, since a spring is interposed between the floating lever of the mechanical governor and the control rack of the fuel injection pump to absorb the relative movement between the two, even when the air actuator is regulating the mechanical governor's internal Despite having a simple configuration that uses the highest and lowest mechanical governor,
It is possible to perform economical driving in which the maximum amount of fuel supplied is suppressed, or constant-speed driving in which the vehicle's traveling speed is maintained at an arbitrary set value.

[Brief explanation of the drawing]

FIG. 1 is a front view of a diesel engine equipped with a fuel supply control device according to an embodiment of the present invention, and FIG.
The figure shows a front view of the main part of the mechanical governor installed in this engine, FIG. 5 is a graph showing changes in the engine torque with respect to the rotational speed of the same engine. FIG. 6 is a cross-sectional view similar to FIG. 3 according to a modification of the above embodiment. The figure is a sectional view similar to FIG. 3 showing another modification. In the symbols used in the drawings, 1...diesel engine, 2...fuel injection pump, 8...control rack, 13...air actuator, 19...microcomputer, 26...return spring, 55... It is a metal bellows.

Claims (1)

[Claims] 1. In a device in which a control rack of a fuel injection pump provided in an engine is controlled by a mechanical governor of the highest and lowest type attached to the fuel injection pump, a floating lever of the mechanical governor and the control rack are connected to the control rack. means for connecting the control rack so as to be relatively movable along the stroke direction of the control rack; a spring that urges the control rack to move in the fuel increasing direction with respect to the floating lever; a stop lever; an air actuator that variably controls the maximum stroke of the control rack by swinging the stop lever along the stroke direction of the control rack; and an electronic device that controls the supply of air to the air actuator. A fuel supply control device comprising: a control device; and a return spring that swings and retracts the stop lever to the outside of a stroke locus of a control rack when the air pressure decreases.