JP2002155763A - Fuel injection device and fuel injection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection device capable of preventing an excess fuel injection during operation of an engine and certainly inhibiting a generation of a harmful unburned component and a black smoke. SOLUTION: A fuel injection pump 31 of the fuel injection device 22 is provided with a plunger 40 for pressurizing a fuel; and a rack 57 for increasing/ reducing a fuel injection amount by turning the plunger to a direction around a shaft. A governor 60 for moving the rack to a starting position where the fuel injection amount becomes the maximum at the time of starting of the engine and a position where an appropriate fuel injection amount is obtained corresponding to an operation state of the engine is auxiliarily provided. An solenoid 62 is installed at an opposite side to the governor of the fuel injection pump. The solenoid pressed the rack moved to the starting position no so as to be moved no more and limits a motion of the rack to a direction of increasing the fuel injection amount before the rack arrives at the starting position after the engine is started.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection device and a fuel injection method for adjusting a fuel injection amount by changing an effective stroke of a plunger by a control rack.

[0002]

2. Description of the Related Art In a diesel engine, air taken into a combustion chamber is compressed at a high compression ratio, and fuel is injected into high-temperature, high-pressure air through a fuel injection pump. Combustion is performed by the self-ignition of grains. For this reason, a fuel injection pump used for a diesel engine is required to inject an appropriate amount of fuel into a combustion chamber according to an ever-changing operating condition of the engine. It is necessary to increase the fuel injection amount in order to enhance the startability.

[0003] In a fuel injection pump used for an industrial vehicle such as a forklift, for example, the effective stroke of a plunger is changed by changing the position of a control rack, and the fuel injection amount is adjusted.

The control rack is reciprocally supported by a pump housing of a fuel injection pump, and is operated by a mechanical governor. The mechanical governor is composed of a flyweight that is rotationally driven by a cam shaft of a fuel injection pump, and various levers and springs that are linked to the flyweight, and is incorporated at one end of the pump body.

FIG. 6 schematically shows a basic structure of a conventional mechanical governor 1. Reference numeral 2 denotes a cam shaft of a fuel injection pump. At the tip of the camshaft 2, two fly weights 3a and 3b are rotatably supported. The flyweights 3a and 3b are opened and closed in the radial direction of the camshaft 2 by the centrifugal force generated when the camshaft 2 rotates, as indicated by arrows in FIG. Fly weights 3a, 3
When b opens radially outward of the camshaft 2, the roller 5 supported at one end of the arm 4 pushes the control block 7 away from the camshaft 2 against the urging force of the spring 6. I have.

[0006] The mechanical governor 1 has a guide lever 8 and a control lever 9. The guide lever 8 is rotatably suspended above the governor cover 10, and the lower end of the guide lever 8 is rotatably connected to the tip of the control block 7.
The control lever 9 has a pivot shaft 11
And is rotatably supported at an intermediate portion of the guide lever 8 through the shaft. The lower end of the control lever 9 is linked to the accelerator pedal 12, and the upper end is connected to one end of a control rack 13 incorporated in the fuel injection pump.

The control block 7 is connected to the camshaft 2
The spring 6 that presses in the direction of (1) includes a weak spring (not shown) that operates during low-speed operation including idling, and a strong spring (not shown) that presses the control block 7 in the above-described direction until the maximum speed operation is reached. In. Therefore, during the intermediate speed operation between the low speed operation and the maximum speed operation, the centrifugal force of the fly weights 3a and 3b and the urging force of the spring 6 are balanced with each other, and the control block 7 is kept stationary. Has become.

In the mechanical governor 1 having such a configuration, when the rotation speed of the camshaft 2 decreases during low-speed operation of the diesel engine, the centrifugal force generated in the fly weights 3a and 3b decreases. Therefore, the urging force of the spring 6 overcomes the centrifugal force and presses the control block 7 in the direction of the camshaft 2, so that the guide lever 8 is rotated clockwise in FIG. By this rotation, the control lever 9 moves following the control block 7, and the control rack 13 is pushed into the fuel injection pump.

As a result, the plunger of the fuel injection pump is rotated in the direction of increasing the fuel injection amount, and the amount of fuel injected into the combustion chamber increases.

When the camshaft 2 exceeds a predetermined rotation speed while the diesel engine is operating near the maximum speed, the centrifugal force generated in the fly weights 3a and 3b overcomes the urging force of the spring 6 and the control block. 7 is pushed in a direction away from the camshaft 2. Therefore, the guide lever 8 is rotated counterclockwise in FIG. 6, and the control lever 9 moves following the control block 7, whereby the control rack 13 is pulled out of the fuel injection pump.

Therefore, the plunger of the fuel injection pump is rotated in the direction of decreasing the fuel injection amount, and the injection amount of the fuel injected into the combustion chamber is reduced, thereby suppressing the overspeed of the diesel engine.

During the intermediate speed operation, the control block 7 is stationary without being affected by the centrifugal force of the fly weights 3a and 3b, so that the position of the pivot shaft 11 connecting the guide lever 8 and the control lever 9 is maintained. Is kept fixed. Therefore, the accelerator pedal 1
When stepping on 2, the control lever 9 moves the pivot shaft 1
The control rack 13 is rotated clockwise around the fulcrum 1 and the control rack 13 is pushed into the fuel injection pump. Therefore, the fuel injection amount increases following the depression of the accelerator pedal 12.

Conversely, when the depression of the accelerator pedal 12 is released, the control rack 13 is pulled out of the fuel injection pump by the control lever 9, and the fuel injection amount is reduced. As a result, during the intermediate speed operation, the fuel injection amount is adjusted by the accelerator pedal 12 linked to the control lever 9.

When the diesel engine is started, it is necessary to inject excess fuel into the combustion chamber in order to enhance the startability. For this reason, the conventional mechanical governor 1 has an adjusting lever (not shown) interlocked with the control lever 9, and this adjusting lever is
The control rack 13 is forcibly pushed into a starting position where the fuel injection amount is maximized.

Further, the conventional fuel injection pump has a limit sleeve on the side opposite to the mechanical governor 1. The limit sleeve is located on an extension along the moving direction of the control rack 13, and when the control rack 13 is pushed toward the starting position,
It comes into contact with the tip of the control rack 13. For this reason, the limit sleeve presses the control rack 13 pushed into the starting position so as not to move any more, whereby the fuel injection amount at the time of starting the diesel engine is determined.

FIG. 7 shows a conventional general mechanical governor 1.
FIG. 7 shows an example of the characteristic curve of FIG.
-D represents the relationship between the rotation speed of the fuel injection pump (cam shaft) and the position of the control rack 13. AB
Indicates the position of the control rack 13 at the time of engine start at which the fuel injection amount becomes maximum. At the time of starting the engine, if excessive fuel is injected into the combustion chamber exceeding the injection amount required for the start, the ratio of fuel to air in the combustion chamber becomes too large, so that incomplete combustion is likely to occur. For this reason, a large amount of black smoke is emitted after the engine is started. Therefore, in the conventional fuel injection pump, the control rack 13 is pressed by the limit sleeve so that the control rack 13 does not move to a position beyond the start point A.

FIG. 7 shows the relationship between the rotational speed of the fuel injection pump (cam shaft) and the position of the control rack 13 during the intermediate speed operation. During the intermediate speed operation, the control block 7 is stationary without being affected by the centrifugal force of the fly weights 3a and 3b, so that the control rack 13 maintains the fixed position.

The point C in FIG. 7 corresponds to the fly weights 3a and 3b.
The centrifugal force that occurs overcomes the biasing force of the spring 6,
The position where the control rack 13 is withdrawn from the fuel injection pump is shown. After the point C, the characteristic is such that the fuel injection amount decreases as the pump rotation speed increases.

[0019]

By the way, in a fuel injection pump having the mechanical governor 1 having the above characteristics,
For example, when sudden acceleration is required, the accelerator pedal 12
Is fully opened from fully closed, the movement of the accelerator pedal 12 is transmitted to the control rack 13 via the control lever 9, and the control rack 13 is
It is pushed too far to the position -B.

As a result, a large amount of fuel is injected into the combustion chamber in the same manner as when the engine is started, even when the engine is operating, so that the balance between the amount of intake air and the amount of fuel injected is lost, resulting in excessive combustion of the fuel. State. Since this excess fuel does not contribute to combustion at all, it becomes an unburned component and is released into the atmosphere, which not only wastes fuel but also causes air pollution.

In addition, since the ratio of fuel to intake air becomes too large, oxygen tends to be insufficient during combustion, and incomplete combustion tends to occur. For this reason, a problem arises in that soot is generated in the combustion chamber, and a larger amount of black smoke is emitted than in normal operation.

The present invention has been made in view of such circumstances, and a fuel injection device and a fuel that can prevent excessive fuel injection during engine operation and reliably suppress generation of harmful unburned components and black smoke. The purpose is to provide an injection method.

[0023]

In order to achieve the above object, a fuel injection device according to the present invention comprises a plunger for pressurizing fuel and an effective stroke of the plunger by rotating the plunger about an axis. A fuel injection pump having a control rack for adjusting the fuel injection amount by moving the control rack to a start position where the fuel injection amount is maximized when the engine is started. A governor that moves the control rack to a position where an appropriate fuel injection amount is obtained in accordance with the control rack, and a control rack that is installed on the opposite side of the governor of the fuel injection pump and is moved to the start position when the engine is started. Not to move, and after starting the engine, the control rack starts It is characterized in that comprises a limiting means for limiting the movement of the control rack in the direction increasing the fuel injection amount reaches the previously position.

In order to achieve the above object, a fuel injection method according to the present invention pressurizes fuel by a plunger driven in synchronization with an engine, and injects the pressurized fuel into a combustion chamber of the engine. In addition, the effective stroke is changed by rotating the plunger around the axis by a control rack that is reciprocated according to the engine operating condition, and the amount of fuel injection injected into the combustion chamber is adjusted. Assuming the method, when the engine is started, the control rack moved to the starting position where the fuel injection amount is maximized is pressed so as not to move any more, and after the engine starts, the control rack reaches the starting position. Previously, the movement of the control rack in the direction to increase the fuel injection amount was limited. That.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.
A description will be given with reference to FIG.

FIG. 1 shows a fuel injection system used for an industrial vehicle such as a forklift. The fuel injection system is a four-cycle diesel engine 21
And a fuel injection device 22. The diesel engine 21 has a cylinder block 23 and a cylinder head 24, and a piston 25 is housed inside the cylinder block 23. The piston 25 is connected to a crankshaft (not shown) via a connecting rod 26.

The cylinder head 24 forms a main combustion chamber 27 in cooperation with the top of the piston 25. A swirl chamber 28 is formed inside the cylinder head 24, and the swirl chamber 28 is connected to a main combustion chamber 27 through an injection port 29.

The water jacket 30 is provided inside the cylinder block 23 and the cylinder head 24, respectively.
Are formed. The water jacket 30 surrounds the piston 25, the main combustion chamber 27, and the vortex chamber 28, and the engine cooling water flows through the water jacket 30.

As shown in FIG. 1, the fuel injection device 22
The fuel injection pump 31 has a row shape. The fuel injection pump 31 has a pump housing 32 supported by the cylinder block 23. As shown in FIG. 2, a cam shaft 33 is housed inside the pump housing 32. The camshaft 33 is located below the pump housing 32. The camshaft 33 is rotationally driven by the crankshaft of the diesel engine 21.
On the cam shaft 33, pump driving cams 34 (only one is shown) corresponding to the number of cylinders are formed.

Further, inside the pump housing 32,
A fuel chamber 36 is formed. The fuel chamber 36 is located above the pump housing 32, and the fuel is supplied to the fuel chamber 36 via a fuel feed pump 37.

The pump housing 32 accommodates a number of pump elements 38 (only one is shown) corresponding to the number of cylinders. The pump element 38 includes a plunger barrel 39 and a plunger 40. The plunger barrel 39 is fixed to the pump housing 32. The plunger barrel 39 has a cylinder 41 on an axis, and the plunger 40 is fitted to the cylinder 41 so as to be able to reciprocate in the axial direction.

The lower end of the plunger 40 has a tappet 42
Through a cam 34 for driving the pump of the cam shaft 33. Therefore, when the cam shaft 33 is rotated, the plunger 40 repeats reciprocating motion according to the shape of the pump driving cam 34.

A control sleeve 43 is mounted on the outer peripheral surface of the plunger barrel 39 so as to be rotatable around the axis. The control sleeve 43
The control pinion 44 is fixed to the outer peripheral surface of the control sleeve 43 while being relatively movable in the axial direction of the plunger 40 while integrally rotating around the axis with the plunger 40.

As shown in FIGS. 1 and 2, a delivery holder 45 is screwed into the upper end of the pump housing 32. A fuel discharge passage 46 is formed inside the delivery holder 45, and the fuel discharge passage 46 is connected to an upper end of the cylinder 41 via a delivery valve 47. The delivery valve 47 forms a fuel pressurizing chamber 48 in cooperation with the upper end of the cylinder 41, and the head 40 a at the upper end of the plunger 40 faces the fuel pressurizing chamber 48. The delivery valve 47 is constantly connected to the fuel pressurizing chamber 48 and the fuel discharge passage 4 via a valve spring 49.
6 is urged in such a direction as to interrupt the communication therewith.

The fuel pressurizing chamber 48 is connected to the fuel chamber 36 via one feed hole 50. The feed hole 50 is opened on the inner peripheral surface of the fuel pressurizing chamber 48,
The plunger 40 is opened and closed by a head 40a.

The downstream end of the fuel discharge passage 46 is connected to a fuel injection valve 52 via an injection pipe 51. The fuel injection valve 52 is mounted on the cylinder head 24 of the diesel engine 21, and injects fuel into the vortex chamber 28 of the cylinder head 24.

As shown in FIG. 3, a lead 54 and an oil hole 55 are formed on the head 40a of the plunger 40. The lead 54 is spirally formed on the outer peripheral surface of the head 40a, and the upper edge of the opening is inclined upward.
The oil hole 55 is located on the axis of the plunger 40, and is open to the upper surface of the head 40 a facing the fuel pressurizing chamber 48 and the lead 54.

FIGS. 3A to 3D show the plunger 40.
The process from the intake of fuel to the pumping by the operation of is continuously shown. 3A, when the plunger 40 reaches the bottom dead center due to the rotation of the camshaft 33, the head 40a of the plunger 40 comes off the feed hole 50. Therefore, the fuel sent from the fuel feed pump 37 flows into the fuel pressurizing chamber 48 by the feed pressure and the suction action of the plunger 40.

As shown in FIG. 3B, the plunger 4
When 0 is pushed up from bottom dead center to top dead center,
The feed hole 5 is formed by the head 40a of the plunger 40.
0 is closed, and the communication between the fuel chamber 36 and the fuel pressurizing chamber 48 is cut off. Therefore, the fuel in the fuel pressurizing chamber 48 is pressurized with the rise of the plunger 40, and when the pressure of the fuel exceeds the opening pressure of the delivery valve 47, as shown in FIG. The valve 47 is opened, and the pressurized fuel is supplied from the fuel discharge passage 46 to the fuel injection valve 52 via the injection pipe 51.

As shown in FIG. 3D, the plunger 4
When the upper edge of the opening of the lead 54 reaches the feed hole 50 with the rise of 0, the high-pressure fuel in the fuel pressurizing chamber 48 flows back from the oil hole 55 to the fuel chamber 36 through the lead 54 and the feed hole 50. For this reason, after the lead 54 communicates with the feed hole 50, even if the plunger 40 moves up, the fuel in the fuel pressurizing chamber 48 is not pressurized, and the fuel injection is terminated by closing the delivery valve 47.

Accordingly, the effective stroke of the plunger 40 from the time when the plunger 40 closes the feed hole 50 and starts pressurizing the fuel until the time when the pressurizing of the fuel is completed is as follows.
The effective stroke is determined by the position of the upper edge of the opening of the feed hole 50 and the lead 54, that is, the axial dimension of the plunger 40 from the lower edge of the opening of the feed hole 50 to the upper edge of the opening of the lead 54. It changes by turning in the direction.

In the example of FIG. 3, as the plunger 40 is rotated clockwise, the upper edge of the opening of the lead 54 moves away from the feed hole 50, so that the effective stroke of the plunger 40 increases and the fuel injection amount increases. Increase. Conversely, when the plunger 40 is rotated in the counterclockwise direction, the upper edge of the opening of the lead 54 approaches the feed hole 50, so that the effective stroke of the plunger 40 decreases and the fuel injection amount decreases.

The adjustment of the fuel injection amount is performed by rotating the plunger 40 around the axis via the control rack 57. Control rack 57
Extends linearly along a direction perpendicular to the plunger 40 and is slidably supported on the upper part of the pump housing 32. The control rack 57 is engaged with the control pinion 44 inside the pump housing 32.

Therefore, by sliding the control rack 57 in accordance with the operating condition of the diesel engine 21, the plunger 40 is rotated at a desired angle around the axis, and the amount of fuel injected into the vortex chamber 28 is adjusted. In this embodiment, the control rack 5
As the cylinder 7 is pushed into the pump housing 32, the fuel injection amount increases.

As shown in FIG. 1, the control rack 5
One end of 7 protrudes outward from one end of the pump housing 32. At one end of the pump housing 32, a mechanical governor 60 that changes the position of the control rack 57 in accordance with the operating condition of the diesel engine 21 is provided.
Is installed. Since the mechanical governor 60 has the same configuration as that of the conventional mechanical governor 1 shown in FIG. 6, the same reference numerals are given to the respective components, and the description thereof will be omitted.

The governor cover 10 of the mechanical governor 60
Is connected to one end of the pump housing 32,
A control rack 57 is provided inside the governor cover 10.
One end has been introduced. One end of the control rack 57 is rotatably connected to the upper end of the control lever 9 so that the control rack 57 is pushed into the pump housing 32 by the control lever 9 or pulled out from the pump housing 32. It has become.

The mechanical governor 6 of the fuel injection pump 31
A limit sleeve 61 is provided at the end opposite to the end 0. The limit sleeve 61 has a hollow cylindrical boss portion 62 protruding outward from an end face of the pump housing 32.
Screwed into. The limit sleeve 61 and the boss portion 62 are located coaxially with the control rack 57, and the limit sleeve 61 and the boss portion 62
The end of the control rack 57 on the opposite side to the mechanical governor 60 is inserted inside.

At the end of the limit sleeve 61, an electromagnetic solenoid 62 as a limiting means is supported. The electromagnetic solenoid 62 has a frame 63 for holding an electromagnetic coil (not shown), and a piston rod 64 supported by the frame 63 so as to be able to protrude and retract. Frame 63
Is screwed into the tip of the limit sleeve 61, and the screwing causes the piston rod 64 to be coaxially positioned on an extension of the control rack 57.

The piston rod 64 is connected to the electromagnetic solenoid 6
When the second electromagnetic coil is excited, the frame 6 is retracted into the frame 63 by a first position, and by a return spring (not shown) when the excitation of the electromagnetic coil is released.
3 and is movable over a second position projecting therefrom.

As shown in FIG. 4A, when the piston rod 64 has been moved to the first position, the tip of the piston rod 64 has moved away from the control rack 57. When the control rack 57 is pushed into the starting position, the tip 64a of the piston rod 64
The control rack 57 is pressed against the end face of the control rack 57 so as to prevent the control rack 57 moved to the start position from moving further in the direction of increasing the fuel injection amount.

Further, as shown in FIG. 4B, when the piston rod 64 is moved to the second position, the piston rod 64 advances toward the control rack 57. Therefore, the tip 6 of the piston rod 64
4a strikes the end of the control rack 57 before it reaches the starting position,
The movement of the control rack 57 in the direction to increase the fuel injection amount is restricted.

The electromagnetic solenoid 62 includes a controller 66
It is excited based on the signal output from. The controller 66 determines whether or not the diesel engine 21 is in the starting state based on the temperature of the engine coolant. In the present embodiment, the controller 66 determines the temperature of the engine coolant flowing through the water jacket 30 as the coolant temperature. A signal S1 detected by the sensor 67 and indicating the temperature of the engine cooling water is input from the water temperature sensor 67 to the controller 66. Then, as shown in FIG. 5, when the temperature of the engine cooling water falls below 0 ° C., the controller 66 sends an excitation signal S2 to the electromagnetic solenoid 62.

Therefore, when the electromagnetic solenoid 62 is excited by the excitation signal S2, the piston rod 64 moves to the first position shown in FIG. 4A, and the piston rod 64 is controlled to the starting position where the fuel injection amount becomes maximum. The rack 57 is pushed in.

At the end of the limit sleeve 61,
A protective cap 68 that covers the electromagnetic solenoid 62 is screwed.

In such a configuration, when starting the diesel engine 21 in which the temperature of the engine cooling water is lower than 0 ° C., the excitation signal output from the controller 66 is provided.
The electromagnetic solenoid 62 is excited by S2, and the piston rod 64 is moved to the first position.

Therefore, when the control rack 57 of the fuel injection pump 31 is largely pushed toward the starting position by the control lever 9 of the mechanical governor 60, the end surface of the control rack 57 abuts on the tip end 64a of the piston rod 64. Therefore, the piston rod 64 moves the control rack 57 moved to the starting position.
Is pressed so as not to move further in the direction of increasing the fuel injection amount, whereby the position of the control rack 57 at the time of starting the engine is determined at the point A in FIG.

When the diesel engine 21 starts, the camshaft 2 of the mechanical governor 60 rotates, so that a centrifugal force is generated in the fly weights 3a and 3b, and the control block 7 is pushed in a direction away from the camshaft 2. Therefore, the guide lever 8 is rotated in the counterclockwise direction in FIG. 6, and the control lever 9 moves following the control block 7, whereby the control rack 57 is pulled out of the fuel injection pump.

As a result, the control rack 57 is moved to an idling position (point B in FIG. 7) where the fuel injection amount is reduced from the starting position. In this idling position,
Since the centrifugal forces of the fly weights 3a and 3b and the biasing force of the spring 6 are balanced, the control rack 57 is kept stationary, and a smooth idling operation is maintained.

On the other hand, when the temperature of the engine cooling water exceeds 0 ° C. with the start of the diesel engine 21, the transmission of the excitation signal S 2 to the electromagnetic solenoid 62 is stopped, and the excitation of the electromagnetic solenoid 62 is released. Therefore, as shown in FIG. 4B, the piston rod 64 of the electromagnetic solenoid 62 projects from the first position to the second position and approaches the end surface of the control rack 57.

As a result, even when the control rack 57 is pushed toward the starting position by a sudden operation of the accelerator pedal 12 during the intermediate speed operation of the diesel engine 21, the end surface of the control rack 57 is Abuts on the tip end 64a of the piston rod 64 before reaching the starting position.

Therefore, the movement of the control rack 57 in the direction to increase the fuel injection amount is restricted, and during the intermediate speed operation, the position of the control rack 57 that defines the maximum fuel injection amount is apparently point A in FIG. Is forcibly moved in the direction of point B. As a result, excessive fuel injection during intermediate speed operation is limited, so that unburned fuel components are not released into the atmosphere, thereby conserving fuel and contributing to improved fuel efficiency. At the same time, pollution can be reduced.

At the same time, during the intermediate speed operation,
The fuel injected into the vortex chamber 28 can be used for combustion without waste, so that the generation of soot accompanying incomplete combustion is suppressed, and the generation of black smoke during acceleration from a low speed range is prevented. Can be.

Further, according to the above configuration, it is possible to cope with the problem by incorporating the electromagnetic solenoid 62 into the existing limit sleeve. Therefore, the mechanical governor 60 and the fuel injection pump 31 having a complicated configuration can be directly used without any significant structural change. It can be used, which is advantageous in terms of cost.

In the present invention, the restricting means for restricting the movement of the control rack is not limited to the electromagnetic solenoid which is excited in accordance with the temperature of the engine cooling water. A controlled hydraulic actuator may be used.

[0065]

According to the present invention described in detail above, even if the control rack is moved toward the starting position after starting the engine, it is possible to increase the fuel injection amount before the control rack reaches the starting position. The movement of the control rack is restricted, and excessive fuel injection during engine operation is suppressed. Therefore, unburned fuel components are not released into the atmosphere, which contributes to improving fuel efficiency by suppressing wasteful use of fuel and reducing pollution. At the same time, while the engine is running, the injected fuel can be used for combustion without waste, so that the generation of soot due to incomplete combustion can be suppressed, and the generation of black smoke during the operation of the engine can be reliably prevented. There is.

[Brief description of the drawings]

FIG. 1 is a side view of a fuel injection system according to an embodiment of the present invention.

FIG. 2 is a sectional view of a fuel injection pump.

FIGS. 3A to 3D are perspective views sequentially showing a process in which fuel is pressurized by a plunger.

FIG. 4A is a cross-sectional view showing a state where a piston rod of an electromagnetic solenoid has been moved to a first position. (B)
FIG. 4 is a cross-sectional view showing a state in which a piston rod of an electromagnetic solenoid is moved to a second position, and movement of the control rack in a direction to increase a fuel injection amount is restricted by the piston rod.

FIG. 5 is a characteristic diagram showing a relationship between a temperature of engine cooling water and an excitation signal of an electromagnetic solenoid.

FIG. 6 is a side view schematically showing a basic configuration of a conventional mechanical governor.

FIG. 7 is a characteristic diagram of a mechanical governor showing a positional relationship between a rotation speed of a fuel injection pump and a control rack.

[Explanation of symbols]

 2 camshaft 21 engine (diesel engine) 31 fuel injection pump 40 plunger 57 control rack 60 governor (mechanical governor) 62 limiting means (electromagnetic solenoid)

Claims (4)

[Claims] 1. A fuel injection pump comprising: a plunger for pressurizing fuel; and a control rack for changing the effective stroke of the plunger by rotating the plunger about an axis to adjust a fuel injection amount. A governor that is attached to the fuel injection pump and moves the control rack to a starting position where the fuel injection amount is maximized at the time of engine start, and moves the control rack to a position where an appropriate fuel injection amount is obtained according to the engine operating condition. The fuel injection pump is installed on the opposite side of the governor, and when the engine is started, the control rack moved to the starting position is pressed so as not to move any more,
A fuel injection device, comprising: a limiter that limits a movement of the control rack in a direction to increase a fuel injection amount before the control rack reaches the start position after the engine is started. 2. The apparatus according to claim 1, wherein the restricting means is an electromagnetic solenoid having a piston rod movable in an axial direction, and the piston rod of the electromagnetic solenoid is moved to the starting position when the engine is started. A first position in contact with the tip of the control rack to keep the control rack in the starting position; and restricting movement of the control rack in a direction in which the control rack is advanced toward the control rack after the engine is started to increase the fuel injection amount. A fuel injection device capable of moving over a second position. 3. The electromagnetic solenoid according to claim 2, wherein the electromagnetic solenoid is excited when the temperature of the engine cooling water at the time of starting the engine is lower than a prescribed value, and holds the piston rod in the first position. Excitation is released when the temperature of the engine cooling water exceeds a prescribed value, and the piston rod projects from the first position toward the second position. 4. A control rack which pressurizes fuel by a plunger driven in synchronization with the engine, injects the pressurized fuel into a combustion chamber of the engine, and reciprocates according to an engine operating condition. In a fuel injection method in which the effective stroke is changed by rotating the plunger around an axis to increase or decrease the fuel injection amount injected into the combustion chamber, the fuel injection amount becomes maximum when the engine is started. Hold down the control rack moved to the starting position so as not to move any more, and after the engine starts, move the control rack in a direction to increase the fuel injection amount before the control rack reaches the starting position. A fuel injection method characterized by limiting.