JP2539667B2 - Fuel injection amount control device for diesel engine for vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fuel injection amount control device for a vehicle diesel engine such as a work vehicle and a small transport vehicle.

(Prior Art and its Problems) Conventionally, as shown in FIG. 5, the governor lever 10 is provided with a maximum fuel injection amount limiting lever 48 facing from the fuel increase side,
A fuel injection amount limiting device has been developed in which the limiting lever 48 is engaged with the adjust ring 4 fixed to the slide rod 36 of the negative pressure actuator 31, for example.

This device rotates the limit lever 48 to the fuel increase side (S1 side) by the slide rod 36 at the time of engine start to secure the fuel increase at the time of start, and when the engine is idling etc. It is rotated to the lower side to limit the fuel injection amount and prevent the generation of black smoke. That is, as shown in the injection amount characteristic graph of FIG. 6, the maximum rack position is secured at the increasing position R1 as indicated by the broken line Y1 at the start, and the rack is moved as shown by the solid line Y3 at the time of idling after the start. Position R3
I am trying to limit the fuel.

However, with the two-stage control method as described above, when accelerating from an idling state of about 700 rpm, fuel becomes insufficient near the initial rotation speed N1 (1000 rpm), resulting in insufficient torque and acceleration. take time. On the other hand, near the rotation speed N2 (2000 rpm) in the low-speed rotation section Y4 during acceleration, conversely, the fuel is a little too much, and black smoke may occur.

(Object of the Invention) An object of the present invention is to make it possible to secure an increased fuel amount at the time of starting and to control the fuel limitation in the low speed rotation region after the start in multiple stages, so that This is to improve the acceleration performance and to sufficiently prevent the generation of black smoke during the acceleration in the low speed rotation range.

(Technical Means for Achieving the Object) In order to achieve the above object, the present invention provides a displaceable fuel restriction for restricting the maximum amount of movement of a fuel injection amount increasing / decreasing member such as a governor lever toward the fuel increasing side. Equipped with a lever,
The second actuators are arranged so as to face each other substantially in the same axis, and an adjust ring that engages with the limiting lever is axially movably fitted to the output slide rod of the first actuator and faces the stopper of the second slide rod. The first actuator is provided with a first spring for urging the first slide rod toward the fuel increase side, and the second actuator is provided with a second spring for urging the stopper toward the fuel decrease side. A third spring that biases the adjust ring toward the fuel increasing side with respect to the first slide rod is arranged on the rod, and the spring force is reduced in order of the first, second, and third springs. The actuators have those ON and OF
The first and second switching valves for switching F are connected to each other, and switching control is performed by the rotation speed detection device, the regulator lever position detection device, or the intake pressure detection device according to the rotation speed, the regulator lever position, or the magnitude of the intake pressure signal. The controller is connected to each switching valve.

(Function) When the engine is started, the adjust ring is moved to the maximum fuel increase side as in the conventional case to secure the fuel increase and maintain a good starting performance.

When accelerating from an idling state or the like, at the beginning of acceleration, the movement of the first slide rod to the fuel increase side and the return action of the adjust ring to the fuel increase side by the third spring may cause a slight increase in the conventional limit. Relax the torque limit to eliminate torque shortage.

Further, in the low speed range during acceleration, the restriction of the stopper of the second actuator or the like is used to make the restriction a little tighter than before, and the generation of black smoke is reliably prevented.

(Embodiment) First, the overall structure of a governor of a diesel engine will be briefly described. In FIG. 1, a governor lever shaft 8 is provided in the governor case 1, and the governor lever shaft 8 includes a thrust lever 9, a governor lever 10 and an inverted L lever. The letter-shaped tension levers 11 are rotatably supported.

At the lower end of the governor case 1, a pump actuating cam shaft 2 extends from the rear fuel injection pump case, and at the front end of the cam shaft 2, a governor sleeve 3 is axially movably fitted and a governor weight 6 is provided. The governor weight 6 is supported so as to be capable of expanding, and the governor weight 6 abuts against the governor sleeve 3 and the governor weight 6 expands due to an increase in the number of rotations of the cam shaft 2 to push the governor sleeve 3 forward. .

The governor lever 10 and the thrust lever 9 are integrally and rotatably connected by a spring 12, and a lower end portion 9a of the thrust lever is provided with a shifter 15 facing the front end surface of the governor sleeve 3 to receive the governor force. It has become. A rear end opening-shaped recess is formed in the lower end of the tension lever 11, and a rear protruding start spring 20 is disposed in the recess, and the rear end of the start spring 28 abuts on the thrust lever lower end 9a. , The start spring 20 can ensure an increase in fuel amount at the time of starting. Further, the lower end of the tension lever 11 is provided with an Angleich mechanism including an Angleich spring 17 and the like.

A rack link 26 is pivotally connected to the upper end of the governor lever 10, and the link 26 is connected to the fuel increasing / decreasing rack of the fuel injection pump 5.

The tension lever 11 has a governor spring 13 stretched between a rear upper end portion and a front end portion of a front regulator lever 14, and the governor spring 13 urges the tension lever 8 toward the fuel increasing side. Regulator lever 14
Is connected to an accelerator lever or the like outside the governor case so that the tension of the governor spring 13 can be adjusted.

A fuel limiter 29 limits the maximum amount of rotation of the tension lever 8 in the fuel increasing direction.

The governor as described above is provided with the fuel injection amount control device according to the present invention. As the fuel injection amount control device, the diaphragm type first and second actuators 31, 32 are arranged at the upper end of the governor case 1 with the same axis center and are opposed to each other in the front and rear direction.
And a fuel injection amount limiting lever 48. The limiting lever 48 is rotatably supported by the governor case 1 via a rotating shaft 30, and the lower end portion 48a faces the front edge of the upper end portion of the governor lever 10 from the front side, and the governor lever 10 has a maximum fuel increase side. The amount of rotation is regulated.

The first actuator 31 is arranged on the front wall of the upper end portion of the governor case 1, and has an actuator case 33, a case lid 34, a rubber diaphragm 35, and a first slide rod 36.
And a first spring (coil spring) 39. The outer peripheral end of the rubber diaphragm 35 is sandwiched between the actuator case 33 and the case lid 35, and a chamber 38 between the case lid 34 and the rubber diaphragm rubber 35 is formed as a negative pressure chamber (pressure fluctuation chamber). The first spring 39 is contracted between the central portion of the rubber diaphragm 35 and the case lid 34, and biases the rubber diaphragm 35 rearward. The central part of the rubber diaphragm 35 is the first
The first slide rod 36 is integrally connected to the slide rod 36, is movable in the front-rear direction in the actuator case 33, and extends rearward.

An adjust ring 41 having an annular groove is axially movably fitted to the first slide rod 36, and a limiting nut 42 is screwed to the rod 36 portion on the rear side of the adjust string 41, so that the adjust string 41 The amount of movement to the rear is regulated. A third spring (coil spring) 45 is contracted between the front surface of the adjust ring 41 and the front spring receiver 43. The spring receiver 43 is engaged with the step portion of the first slide rod 36.

The second actuator 32 is arranged at the rear end portion of the governor case 1 and has a substantially similar structure to the first actuator 31, although the front-back direction is opposite. That is, the actuator case 53, the case lid 54, the rubber diaphragm 55,
A second slide rod 56 and a second spring (coil spring) 59 are provided, and a chamber 58 between the rubber diaphragm 55 and the case lid 54 is formed as a negative pressure chamber (pressure fluctuation chamber). Second spring
Reference numeral 59 urges the rubber diaphragm 55 forward, the second slide rod 56 extends forward, and a bottomed cylindrical stopper 60 is screwed to the front end portion thereof. The front end edge of the stopper 60 opposes the rear end edge of the adjust ring 41 in a pushable manner.

The spring strength F1 of the first, second and third springs 39, 59 and 45,
The relationship between F2 and F3 is F1>F2> F3.

The negative pressure chambers 38 and 58 of the actuators 31 and 32 are connected to the switching valves 61 and 62, respectively. The switching valves 61 and 62 are equipped with, for example, electromagnetic solenoids, and the negative pressure chambers 38 and 58 are connected to a vacuum pump. And a negative pressure supply source 66 and atmosphere introducing portions 63 and 64 are switchably connected. A controller 70 is connected to each of the switching valves 61 and 62 for switching operation, and the controller 70 is connected to a rotation speed detection device 71 and switches to each of the switching valves 61 and 62 according to a set rotation speed. It emits a signal.

The function of the controller 70 will be described in detail. When the engine is started, the first switching valve 61 is switched to the atmosphere side, and the second switching valve 62 is switched to the negative pressure side. Rotation speed section X2 (0 to 1000 rpm
(Strong), both switching valves 61 and 62 are switched to the negative pressure side,
In the rotation speed section X4 (1500 rpm to 2000 rpm or more), both switching valves 61,
Both 62 are switched to the atmosphere side, and the first switching valve 61 is switched to the negative pressure side and the second switching valve 62 is switched to the atmospheric side in the section X3 (1000 rpm to 1500 rpm) between the sections X2 and X4. ing.

In FIG. 3, it is expressed as ON when the switching valves 61 and 62 are switched to the atmosphere side, and OFF when switched to the negative pressure side.

The operation will be described. In FIG. 3, when the engine is stopped and started, the first switching valve 61 is placed on the atmospheric side as shown in the first stage.
The second switching valve 62 is switched to the negative pressure side. As a result, the first spring 39 extends rearward to move the first sly rod 36 rearward to the maximum extent, while the second slide rod 56 retracts rearward and the stopper 60 is separated from the adjust ring 41. The third spring 45 also extends and pushes the adjust ring 41 rearward until it abuts the limiting nut 42 on the first slide rod. Therefore, the adjust ring 41 has moved to the maximum rearward, the limit lever 48 in FIG. 1 has rotated to the maximum arrow S1 side (fuel increase side), and the start spring 20 ensures a sufficient start increase. it can. In FIG. 4, it is a portion of X1 indicated by a broken line.

The lowest section X2 in the low speed range during operation after engine start
Then, as shown in the second stage of FIG. 3, both switching valves 61 and 62 are connected to the negative pressure side. This makes the first sly rod
36 compresses the first spring 39 to move forward, while the second slide rod 56 compresses the second spring 59 to retract backwards, and the stopper 60 separates from the adjust ring 41. Further, the third spring 45 extends to restrict the adjusting ring 41 to the limiting nut 42.
Pushing backwards until it touches. That is, although the first slide rod 36 is moved forward, the adjust ring 41 is also moved forward, but the third spring 45 causes the adjuster ring 41 to be returned slightly backward. Therefore, the limit lever 48 in FIG. 1 moves to the arrow S2 side (fuel reduction side) and moves to the governor lever 10
The maximum fuel injection amount is limited,
Since the spring 45 extends to press the adjust ring 41 against the rearward limiting nut 42, the limiting lever 48 shown in FIG.
Is located. This is the rack position R2 in FIG.

In the rotational speed section X3 (1000 rpm to 1500 rpm) in the low speed rotational range after the engine is started, the first switching valve 61 is on the negative pressure side and the second switching valve 6 is
2 is connected to the atmosphere side. As a result, the first slide rod 36 moves forward, the second slide rod 56 also moves forward, the adjust ring 41 moves forward together with the first slide rod 36, and further forward by the stopper 60 of the second slide rod 56. The third spring 45 is compressed. Therefore, the restriction lever 48 in FIG. 1 is rotated further toward the fuel reduction side than in the case of the section X2, and the maximum injection amount is restricted to R3 lower than R2 as shown in FIG. This R3 is substantially at the same position as the conventional R3 in FIG.

In the rotation speed section X4 of the low speed rotation range, both of the switching valves 61 and 62 are switched to the atmosphere side. As a result, the first slide rod 36 moves rearward, the second slide rod 56 moves forward, and the stopper 60 pushes the adjust ring 41 forward to compress the third spring 45. Therefore, the limiting lever 48 is kept at a position slightly rotated from the rack position R2 to the fuel increase side, and further to the fuel decrease side from the conventional limit amount near Y4 in FIG.

During operation, when accelerating from an idle speed lower than the rotational speed N1 shown in Fig. 4, the rack position can be moved to the rack position R2 in the initial stage of acceleration, so the fuel limit is slightly relaxed within the range where black smoke does not occur. , Insufficient torque near the rotation speed N1 (1000 rpm) is eliminated.

In the range of section X3 of the low speed rotation range during acceleration, it is limited to the R3 position as before. In this section, the number of revolutions has risen to some extent, so there is almost no torque shortage,
Moreover, as in the past, the generation of black smoke is prevented.

Then, in the next stage of the section X4, the fuel restriction is relaxed, but the fuel is restricted to the rack position R4 which restricts the fuel a little more than in the conventional case of Y4 in FIG. Therefore, the generation of black smoke is sufficiently prevented in this section.

In this way, when accelerating from idling, the acceleration performance is improved by slightly relaxing the fuel limitation near the rotational speed N1 at the initial stage of acceleration from the conventional limitation, and the rotational speed N2 in the low speed rotational range during acceleration is also increased. By making the fuel limit a little tighter than before, it is possible to reliably prevent the generation of black smoke.

(Another embodiment) (1) In the device shown in FIG. 2, the inlets of the switching valves 61 and 62 are connected to a positive pressure supply source such as an accumulator 86, and the switching valves 6 are connected.
The outlets of 2, 63 are connected to the chambers 88, 89 of the actuators 31, 32 on the opposite side to the spring accommodating chambers, respectively, and the chambers 88, 89 described above are connected.
Is a pressure fluctuation chamber (positive pressure chamber).

That is, instead of compressing the springs 39 and 59 with a negative pressure as in the above embodiment, they are compressed with a positive pressure. Therefore, when corresponding to FIG. 3, each actuator 31,
It can be set to OFF when 32 is connected to the positive pressure side and OFF when connected to the atmosphere.

(2) The first spring 39 shown in FIG.
31 is contracted between the rear end surface of the actuator case 33 and the spring receiver 43 so that the first slide rod 36 is biased rearward, while the second spring 59 moves the second actuator 59.
It may be arranged such that the second slide rod 56 is biased rearward by being contracted between the front end face of the 32 actuator case 54 and the stopper 60.

(3) As the first, second, and third springs, a plurality of cone springs or leaf springs may be compressed.

(4) Instead of the rotation speed detecting device, a controller for performing switching control according to the regulator lever position by the regulator lever position detecting device may be connected to each switching valve as in the invention of claim (2).

(5) Instead of the rotation speed detecting device, a controller for performing switching control according to the magnitude of the intake pressure signal by the intake pressure detecting device may be connected to each switching valve as in the invention described in claim (3). .

(6) Although the illustrated embodiment has a structure in which the governor lever is opposed to the limiting lever, for example, a metal fitting may be provided on the rack link 26 and the limiting lever may be opposed to the metal fitting.

(Effect of the Invention) As described above, the present invention includes the first and second actuators 31 and 32 facing each other in order to control the maximum fuel injection amount by facing the governor lever 10 or the like,
The first and second springs 39 and 59 for moving the first and second slide rods 36 and 56, respectively, and the third spring 45 for moving the slidable adjust ring 41 on the first slide are provided. Since the maximum fuel injection amount can be controlled in multiple stages at the time of acceleration in the rotation range, there are the following advantages.

(1) Compared to the structure of controlling in two stages of the starting increase line and the limit line as in the conventional example of FIGS. 5 and 6, for example, in acceleration from idling after starting, in the initial stage of acceleration, as shown in FIG. It is possible to improve the acceleration performance in the low speed region by eliminating the torque shortage by relaxing the fuel limitation a little like the speed N1.

(2) On the other hand, in the low speed rotation range during acceleration, near the rotation speed N2, the fuel limit is tighter than before, and the generation of black smoke can be stopped within the range where the torque does not decrease.

(3) Of course, at the time of start-up, it is possible to secure a sufficient increase in the amount of start-up as in the conventional case, and to secure good starting performance.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a fuel injection amount control device according to the present invention,
FIG. 2 is a longitudinal sectional view of another embodiment, FIG. 3 is a schematic view showing the states of the adjust ring in each rotational speed section in correspondence with the states of the switching valve, and FIG. 4 is a fuel injection amount characteristic diagram. FIG. 5 is a longitudinal sectional view of the conventional example, and FIG. 6 is a fuel injection amount characteristic diagram of the conventional example. 10 …… Governor lever, 14 …… Regulator lever, 31,32 …… First and second actuators, 36 …… First
Slide rod, 39 ... first spring, 41 ... adjust ring, 48 ... fuel injection amount limiting lever, 61, 62 ... first,
Second switching valve, 70 ... Controller

Claims (3)

(57) [Claims] 1. A displaceable fuel injection amount restricting lever for restricting a maximum amount of movement toward a fuel increase side with respect to a fuel injection amount increasing / decreasing member such as a governor lever, and the first and second actuators have substantially the same axis. The adjust rings, which are arranged to face each other and engage with the limiting lever, are axially movably fitted to the output first slide rod of the first actuator and face the stopper of the second slide rod so that the adjuster is attached to the first actuator. Includes a first spring for urging the first slide rod toward the fuel increase side, a second spring for urging the stopper toward the fuel decrease side is disposed in the second actuator, and the first slide rod includes the first slide. A third spring for urging the adjust ring toward the fuel increase side is arranged with respect to the rod.
The spring force is reduced in order of the second and third springs, and the first and second actuators are connected to the first and second switching valves for switching between ON and OFF, respectively. A fuel injection amount control device for a vehicle diesel engine in which a controller that controls switching according to a signal is connected to each switching valve. 2. A fuel injection amount for a vehicle diesel engine according to claim 1, wherein a controller for switching control according to the regulator lever position by the regulator lever position detecting device is connected to each switching valve instead of the rotation speed detecting device. Control device. 3. A fuel for a diesel engine for vehicle according to claim 1, wherein instead of the rotation speed detection device, a controller for switching control according to the magnitude of the intake pressure signal by the intake pressure detection device is connected to each switching valve. Injection amount control device.