JPH0533705Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention is a diesel engine with a positive displacement supercharger that uses a positive displacement supercharger to increase torque in the extremely low speed range. When a boost compensator was used in a diesel engine with a feeder, a sufficient amount of fuel was not injected in the extremely low speed range and the torque did not increase. However, the present invention relates to a boost compensator for a positive displacement supercharged diesel engine that makes it possible to increase the amount of fuel injected.

Conventional technology In conventional turbocharged diesel engines, it was difficult to supply a sufficient amount of intake air from the turbocharger to the engine at low speeds when the amount of exhaust gas supplied from the engine was low. . In such cases, even if you try to supply a large amount of fuel to the engine by fully depressing the accelerator pedal to increase torque, the engine does not receive enough intake air to compensate for the increase, resulting in incomplete combustion and exhaust smoke. This resulted in deterioration of performance.

Therefore, in order to prevent such incomplete fuel as much as possible, the discharge air pressure of the turbocharger, that is, the boost pressure, is detected, and if the boost pressure is lower than the set value, the fuel supply is restricted. A boost compensator was used. Such a boost compensator receives boost pressure in a pressure chamber partitioned by a diaphragm pressed by a boost compensator spring, and the reduction of the diaphragm due to the boost pressure operates a control rack via an operating member and a lever. The amount of fuel injected was controlled by increasing or decreasing the amount of fuel injected.

Hereinafter, a conventional boost compensator will be explained with reference to FIG. 1, where 10 is a diesel engine and 20 is a turbo supercharger. 11 is a boost compensator, and a turbo supercharger 20
The pressure chamber 12 of the boost compensator receives the boost pressure, and the pressure chamber has a diaphragm 14 that is separated from the atmosphere and is provided with a push rod 13, and the diaphragm is pressed by the boost compensator spring 15 to increase the boost pressure. Equilibrium. Further, an actuating member 16 is pressed into contact with the push rod 13 by a starting increase spring 17. One end of a lever lever 18, which is supported by a pivot 18a, comes into contact with the operating member 16, and the other end contacts a stopper 19 of a control rack 19 that operates a plunger mechanism that controls the increase and decrease of the fuel injection amount.
It is in contact with b.

Note that the control rack 19 has a cancel mechanism 19a, and 19a' is its spring;
9a'' is an actuation bar connected to the governor body and an accelerator pedal mechanism (not shown).

Therefore, when the driver depresses the accelerator pedal to increase torque, the fuel supply to the diesel engine 10 is stopped by the cancel mechanism 1.
The operating bar 19a'' at 9a is the spring 19
Move in the direction that compresses a′. However, since the rotation speed of the diesel engine 10 is low and the amount of exhaust gas supplied to the exhaust gas turbine 20a of the turbo supercharger 20 is small, the boost pressure by the compressor 20b is low, so that the boost pressure is lower than the pressure chamber 12.
Even if the pressure was supplied within the boost compensator spring 15, the pressure was lower than the set pressure of the boost compensator spring 15 and the diaphragm 14 could not be pressed down. In such a case, since the diaphragm 14 is not pushed down, the actuating member 16 also does not fall, and no matter how much the driver depresses the accelerator pedal, the stopper 19b stops at the position where it contacts the foot lever 18 and does not move. Therefore, the control rack 19 could not be moved further in the direction of increasing the fuel injection amount (to the left in the figure). However, when the engine speed increases and the increase in boost pressure exceeds the pressure of the boost compensator spring 15 and starting increase spring 17, the diaphragm 14 is compressed, the operating member 16 is lowered, and the foot lever 18 is rotated (clockwise). direction) and stopper 19
The stop caused by b is released and control rack 1 is reached.
9 was decided to be moved in the direction of increasing the fuel injection amount.

Therefore, according to Figure 2, the engine speed Ne
When the increase/decrease in the amount of fuel injection is shown by the positional relationship of the control rack, the line a (imaginary line) shows the positional relationship of the control rack due only to the governor body, and the line b (broken line) shows the balance between the boost compensator spring 15 and the boost pressure. In contrast, line c (solid line) shows the positional relationship of the control racks in the boost compensator constructed in this way. As shown in the figure, the positional relationship of the control rack is shown when the control rack is arranged in parallel with the boost compensator spring 15 to increase the amount of fuel injection.

Note that in the figure, range d is the amount of increase due to the provision of a starting increase spring, which the actuating member presses against the push rod, in parallel with the boost compensator spring, and is the operating range of the boost compensator.

Problems to be Solved by the Invention However, in order to increase the torque when starting the engine, conventional methods have used a boost compensator in which the starting volume increase spring is installed in parallel with the boost compensator spring to increase the amount of fuel injection. However, due to the structure of the engine, it was not possible to increase the fuel injection amount enough to produce torque in the extremely low speed range of the engine.
That is, as shown by line c in FIG. 2, no matter how many starting increase springs 17 are disposed in the boost compensator 11 in parallel with the boost compensator spring 15, the increase in fuel injection amount by the boost compensator is within the range d. ,
In the extremely low speed range (400 to 500 rpm), the amount of fuel injection is prevented from increasing due to structural features, and even more so since a positive displacement supercharger is used to increase torque in the extremely low speed range of the engine. However, with the conventional boost compensator installed as described above, there was a problem that a sufficient amount of fuel could not be injected in the extremely low rotation speed range, the torque could not be increased, and starting performance could not be improved.

Therefore, the present invention consists of a boost compensator spring that presses a diaphragm, which is compressed by boost pressure, in opposition to the boost pressure, and an actuating member mounted on a push rod provided on the diaphragm. To provide a boost compensator whose purpose is to increase the amount of fuel injection in an extremely low speed rotation range of an engine by arranging it in series with a starting increase spring that is brought into contact and pressed. .

Means for Solving the Problems The present invention receives boost pressure from a turbocharger into a pressure chamber partitioned by a diaphragm pressed by a boost compensator spring, and the compression of the diaphragm affects the operating member and the lever. In the boost compensator, which operates the control rack through the boost compensator to increase or decrease the amount of fuel injection, it increases the amount of fuel injection at the time of startup when using a positive displacement supercharger by increasing the torque in the extremely low speed rotation range. In order to do this, a starting boosting spring is provided that presses the operating member into contact with a push rod provided on the diaphragm, and one end of the starting boosting spring is actuated so that the starting boosting spring is in series with the boost compensator spring. An engine with a positive displacement supercharger, characterized in that the other end is in contact with and fixed to the other end edge of a sheet with one end interposed in a part where a boost compensator spring is in press contact with a diaphragm. It is a boost compensator.

Operation Therefore, the present invention arranges the starting spring in series with the boost compensator spring balanced by the boost pressure so that the amount of fuel injected at the time of starting is increased, and for this purpose, the operating member is always Since it is pressed into contact with the push rod provided on the diaphragm, the amount of fuel injected is increased by a certain amount by the operation of the starting increase spring even in the extremely low speed range, and the torque is increased. Even if a positive displacement supercharger is used for this purpose, the boost compensator can sufficiently increase the fuel injection amount and increase the torque.

Embodiments Hereinafter, embodiments of the boost compensator of the present invention will be explained based on the drawings. As shown in FIG. There is a pressure chamber 2 which is partitioned, and a push rod 3 is provided on the diaphragm 4 of the pressure chamber, and an actuating member 6 is pressed into contact with the push rod 3 by a starting increase spring 7. The starting increase spring 7, which has one end in contact with the actuating member 6, has its other end in contact with the other end edge 4a'' of the seat 4a, which has one end edge 4a' interposed in the portion where the boost compensator spring 5 is pressed against the diaphragm 4. The actuating member 6 is pressed into contact with the push rod 3 provided on the diaphragm 4, which is compressed by the boost pressure by the starting increase spring 7, and is in series with the boost compensator spring 5. One end of the pivoted lever 8 is abutted, and the other end of the lever 8 is abutted against a stopper 9b of a control rack 9 that operates a plunger mechanism that controls increase/decrease of the fuel injection amount.

Note that 9a is a cancel mechanism, 9a' is a spring, and 9a'' is an actuation bar connected to the accelerator pedal and the governor body.

Therefore, when the driver depresses the accelerator pedal to increase torque in the engine's extremely low speed range, the actuation bar 9a'' is activated, but due to the low boost pressure of the turbocharger, the drop is small. Actuation member 6
Since the stopper 9b of the control rack 9 is brought into contact with and stopped by the lever 8 in contact with the lever 8, the spring 9a' of the cancel mechanism 9a is compressed. By the way, by arranging the boost compensator spring 5 and the starting increase spring 7 in series, so that the starting increasing spring always presses the operating member 6 into contact with the push rod 3 provided on the diaphragm 4, it is possible to control the engine speed regardless of the engine speed. Also, the fuel injection amount can be increased to a certain degree, and the boost pressure rises quickly. When the diaphragm 4 pressed by the boost compensator spring 5 is pushed down by such boost pressure, and the actuating member 6 that contacts the push rod 3 is lowered, the lowering of the actuating member 6 causes one end to come into contact with the actuating member. The contact lever 8 is allowed to rotate (clockwise) on the pivot shaft 8a, and the control rack 9, which was stopping the stopper 9b in contact with it at the other end, is allowed to move, and the control rack 9 is compressed by the cancel mechanism 9a. The control rack 9 is actuated in the direction of increasing the fuel injection amount by the spring 9a'. Therefore, even if a positive displacement supercharger is used, a sufficient amount of fuel can be injected.

To explain this state in terms of the relationship between the control rack position and the engine speed, as shown in FIG. ), the control rack 9 position by the boost compensator in which the starting increase spring 7 is connected in series with the boost compensator spring 5 is line e (solid line), and the starting increase spring 7 in series with the boost compensator spring 5 is in series with the actuating member 6. The increase in fuel injection amount relative to the engine rotational speed obtained by the boost compensator brought into pressure contact with the push rod 3 falls within the illustrated range f. Therefore, even in the extremely low speed range (400 to 500 rpm) of a diesel engine, the amount of fuel injected will always be increased by a certain amount, so it is difficult to use a diesel engine that uses a positive displacement supercharger in the very low speed range. As a result, the fifth
As shown in the figure, the torque T relative to the engine speed Ne can be increased by a range i from the g line (broken line) to the h line (solid line).

Effects of the invention As a result of the above, the present invention can always increase the fuel injection amount at a constant level even in the extremely low rotation speed range by using the starting increase spring arranged in series with the boost compensator spring. Even if a type supercharger is used, there will be no shortage of fuel supply, and the fuel supply will be sufficient to match the intake air, making it possible to reliably increase torque, thus improving engine startability. I will do it.

[Brief explanation of drawings]

FIG. 1 is a structural diagram of a conventional boost compensator, and FIG. 2 is a relationship diagram showing the positional relationship of a control rack with respect to engine speed in the boost compensator. Third
4 is a structural diagram of the boost compensator of the present invention, FIG. 4 is a relationship diagram showing the positional relationship of the control rack with respect to engine speed in the boost compensator, and FIG. 5 is a diagram showing the torque relationship. It is. 1,11...Boost compensator, 2,1
2...Pressure chamber, 3,13...Push rod,
4,14...Diaphragm, 5,15...Boost compensator spring, 6,16...Operating member, 7,17...Start increase spring, 8,1
8...foot lever, 8a, 18a...axis,
9, 19...Control rack, 9a, 19a
...Cancel mechanism, 9a', 19a'...Spring, 9a'', 19a''...Operating bar, 9b, 19b...
...stopper, 10...diesel engine, 2
0...Turbo supercharger.

Claims (1)

[Scope of utility model registration request] Boost pressure from the turbocharger is received in a pressure chamber partitioned by a diaphragm pressed by a boost compensator spring, and the reduction in pressure of the diaphragm operates a control rack via an operating member and a lever lever to control the fuel injection amount. In a boost compensator that is operated to increase or decrease, when using a positive displacement supercharger to increase the torque in the extremely low rotation speed range, the operating member is pressed against a push rod provided on the diaphragm in order to increase the amount of fuel injected. The other end edge of the seat is provided with a starting increasing spring that is in contact with the boost compensator spring, one end of which is in contact with the actuating member, and the other end of the starting increasing spring is in pressure contact with the diaphragm. Fix it in contact with the
A boost compensator for a positive displacement supercharged engine, characterized in that the fuel injection amount is increased by connecting a starting increase spring and a boost compensator spring in series.