JPH0355796Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field of the invention] The invention reduces the so-called "free accelerator smoke" that occurs when the accelerator of a supercharged diesel engine is greatly depressed at or near no load. Regarding equipment.

[Prior art]

In a supercharged diesel engine, a boost compensator is used to increase the amount of fuel injected in response to changes in boost pressure when the supercharger is activated.

However, this boost compensator is configured to increase the fuel injection amount in response to an increase in boost pressure as the engine speed increases, regardless of the engine load.
Therefore, even if the accelerator is pressed heavily under no-load conditions, the amount of fuel injected will increase when the boost pressure increases slightly near maximum rotation, resulting in a large amount of smoke, or free accelerator smoke, resulting in air pollution. is occurring.

Fig. 4 is a characteristic diagram showing the relationship between the position of the fuel injection pump rack and engine speed, and Fig. 5 is a characteristic diagram showing the relationship between fuel injection amount and engine speed drawn corresponding to Fig. 4. It is a diagram.

In both figures, curves A and A' show the state of full-load operation, and curves B and B' show the state where the boost compensator is operating. When the pedal is depressed, a large amount of free accelerator smoke is generated when the engine speed rises above points C and C', causing problems such as air pollution.

As a countermeasure to this free acceleration smoke, a method has been proposed in which, as shown in curves D and D', the stroke of the boost compensator is increased in the free acceleration state to lower the position of the rack, thereby reducing the overall fuel injection amount. However, there are problems with this method.

That is, as shown in FIG. 5, when the accelerator is depressed to start the vehicle, the amount of fuel injected decreases as the engine rotation increases and reaches its lowest value at point E. Therefore, the output is reduced at the accelerator position where output is required to start the vehicle, resulting in a drawback that the starting performance is deteriorated.

Therefore, in the state of free acceleration, the fuel injection amount is increased through curve B' until the engine speed reaches point E in Figure 5, and at higher engine speeds, the fuel injection amount is increased.
If the fuel injection amount is slightly increased by shifting to D', free acceleration smoke can be eliminated and the vehicle's starting performance can be improved.

[Purpose of invention]

The present invention provides a device that reduces the free acceleration smoke of the conventional supercharged diesel engine and improves the starting performance of the vehicle.

[Summary of the idea]

In order to achieve the above object, the present invention provides a temporary fixing means that fixes the spring interposed between the governor lever and the modulator link at the maximum depression position of the accelerator pedal, and releases it at the position where the accelerator pedal is depressed less than the maximum depression position. This is an accelerator smoke reduction device for a supercharged diesel engine.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing the main parts of a device for reducing free acceleration smoke in a supercharged diesel engine according to the present invention, in which 1 is a governor mechanism that rotates in conjunction with the rotation of the engine; The governor link 2 that constitutes moves the governor lever 3 back and forth. The governor lever 3 is housed in a modulator link 4, transmits its movement to the modulator link 4 via a spring 5, and moves the control rack 6 of the fuel injection pump back and forth to adjust the amount of fuel injected. do.

The end of this control rack 6 is a stopper 7.
The stopper 7 comes into contact with a receiving portion 10 provided on an adjusting rod 9 of the boost compensator 8, so that its movement amount is regulated.

As shown in FIGS. 2 and 3, the modulator link 4 is provided with an elongated hole 15, and the pin 16 planted in the modulator link 4 is inserted into the elongated hole 15.
They are beginning to move within.

Furthermore, a fixed claw 18 is provided on the modulator link 4.
is rotatably supported via a pin 17, and a spring 19 acts on this fixing pawl 18 with an elastic force that causes it to rotate in the direction of arrow A.

Note that FIG. 2 shows a state in which the fixing claw 18, which rotates due to this elastic force, stops at a predetermined position and is just before the pin 16 comes into contact with the pin 16. In this case, the fixing claw 18 is rotated in the direction opposite to the arrow A, so that the pin 16 falls into the hook portion 18b and the two engage with each other.

Further, the fixed claw 18 is provided with a guide surface 18c, and the release pin 20 fixed to the bracket 21 comes into contact with the guide surface 18c, thereby causing the engagement between the hook portion 18b and the pin 16 set on the governor lever 3. is configured to release the connection.

Next, the operation of the device according to the present invention will be explained.

(In the case of normal operation) When the accelerator pedal is depressed to start the vehicle, the governor lever 3 moves in the direction I of fuel increase due to the action of the governor mechanism 1. This movement of the governor lever 3 is transmitted to the modulator link 4 via the spring 5, which moves the control rack 6 in the direction of arrow I, increases the amount of fuel injected, and generates the engine output necessary for starting the vehicle. .

When the boost pressure increases as the engine speed increases, the receiving part 10 provided at the tip of the adjusting rod 9 of the boost compensator 8 moves in the direction of arrow B, so the stopper 7 moves clockwise. As the control rack 6 rotates and moves backward, the control rack 6 moves in the direction of arrow I, further increasing the amount of fuel injected and increasing the output of the engine.

(Free accelerator state) When the accelerator is depressed greatly in free accelerator, that is, in a no-load state or in a state close to this, a ``delay'' occurs between the amount of accelerator depression and the increase in boost pressure. become.

The invention is to utilize this "delay" to lock the spring 5 in the modulator link 4 into a non-actuated state.

Now, if you press the accelerator pedal hard in a no-load state, the engine speed will increase, but
Since the governor mechanism 1 rotates in accordance with the movement, the governor lever 3 suddenly moves in the direction of arrow I. Along with this movement, the control rack 6 moves while it fills the gap g between it and the stopper 7. However, the time for which this control rack 6 moves is very short.

As mentioned above, when the engine speed increases with the control rack 6 in contact with the stopper 7, the pin 16 moves in the direction of arrow I because the governor lever 3 moves in the direction of arrow I while the control rack 6 is fixed. Then, the front end 18a of the fixing claw 18 is pushed and the fixing claw 18 is rotated in the direction opposite to the arrow A, so that the pin 18 finally engages with the hook portion 18b at the position 18'.

In this state, the spring 5 is in its most compressed state, and the governor lever 3 and modulator link 4 are integrated by the fixing claw 18. In other words, if the accelerator pedal is depressed greatly when the engine is under no load, the governor link 3
suddenly moves in the direction of increasing fuel, and the control rack 6 and governor lever 3 are temporarily integrated through mechanisms such as the pin 16 and the fixing pawl 18, resulting in a locked state.

When the governor lever 3 is moved back in the direction of arrow D in which the fuel decreases in the locked state, the control rack 6 is also quickly moved back in the direction of arrow D at the same time. In other words, it means that the control rack 6 quickly retreats in the direction of decreasing fuel at a position where the fuel injection amount is large.

Next, when the governor lever 3 is retreated to a certain range, the release pin 20 and the guide surface 18c of the fixed claw 18 come into contact with each other, and the fixed claw 18 is rotated counterclockwise to prevent the engagement between the pin 16 and the fixed claw 18. Release it and allow the spring 5 to operate. This spring 5
By operating the boost compensator 8, the boost compensator 8 operates normally.

FIG. 6 shows the easy-to-use
Fig. 7 shows the relationship between [fuel injection amount and engine speed], and curves A and A' show the relationship between [fuel injection amount and engine speed], respectively, and curves A and A' correspond to full-load operation corresponding to Figs. 4 and 5. state.

Curves M and N respectively indicate the operation of the device according to the present invention, and in the range where the engine speed is higher than the position f, the governor link 3 and modulator link 4 are integrated as described above. In order to move backward, the position of the control rack 6, that is, the amount of fuel injection, is reduced by the shaded area in FIGS. 6 and 7.

[Effect of idea]

As explained above, the device according to the present invention provides a spring 5 (modulator spring) between the governor lever 3 and the modulator link 4 of the boost compensator of a diesel engine with a supercharger.
It is distinctive in that it is configured to be inactive when the accelerator is free.

Therefore, according to the present invention, when the accelerator pedal is depressed greatly with the engine under no load and the engine speed increases, the governor lever 3 and control rack 6 are also suddenly moved backward within a range of f or more. As a result, the amount of fuel injected decreases rapidly as shown in the shaded area in Figure 7.
The occurrence of so-called free acceleration smoke can be prevented, and the problem of air pollution can be solved.

However, when the amount of depression of the accelerator pedal is small, the amount of fuel injected is the same as that of a normal engine, so the vehicle starts easily.

Further, since the device according to the present invention only requires adding a few parts to the currently used supercharged diesel engine, the cost will not increase.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an outline of the accelerator smoke reduction device for a supercharged diesel engine according to the present invention, Fig. 2 is a front view showing the fixing mechanism between the governor lever and the modulator link, and Fig. 3 is a side view of the same. be. FIG. 4 is a diagram showing the relationship between the rack position and engine rotation of a conventional fuel injection pump, and FIG. 5 is a diagram showing the relationship between the conventional fuel injection amount and engine rotation. FIG. 6 is a diagram corresponding to FIG. 4 in the apparatus according to the present invention, and FIG. 7 is a diagram corresponding to FIG. 5 in the apparatus according to the present invention. 1...Governor mechanism, 2...Governor link, 3...
...Governor lever, 4...Modulator link, 5
... Spring, 5 ... Control rack, 7
...Stopper, 8...Boost compensator,
9...Adjusting rod, 10...Receptacle, 1
5... Long hole, 16, 17... Pin, 18... Fixed claw, 18a... Front end, 18b... Hook portion, 19...
Bracket, 20...Release pin.

Claims (1)

[Scope of utility model registration request] An accelerator smoke reduction device for a supercharged diesel engine, which is provided with a fixing means between a governor lever and a modulator link, which is fixed at the maximum depression position of the accelerator pedal and released at a position where the accelerator pedal is depressed less than the maximum depression position.