JPH0533706Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention is extremely useful when the boost compensator of a conventional turbocharged diesel engine is adopted in a diesel engine equipped with a turbo supercharger or a positive displacement supercharger. In order to resolve the issue where a sufficient amount of fuel was not injected in the low-speed rotation range, the structure of the boost compensator was improved and the foot lever was activated by an actuator at the same time as the positive displacement supercharger's changeover switch was turned on, allowing control by the foot lever. Turbo superchargers and positive displacement superchargers that are capable of increasing the amount of fuel injection in accordance with the amount of depression of the accelerator pedal by releasing the contact stop of the rack and making the control rack free. This relates to a boost compensator for a diesel engine.

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 press the accelerator pedal all the way down to increase torque and supply a large amount of fuel to the engine, the engine does not receive enough intake air to compensate for the increased torque, resulting in incomplete combustion and exhaust smoke. This resulted in deterioration of performance.

Therefore, in order to prevent such incomplete combustion, 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. In such a boost compensator, boost pressure is received in a pressure chamber partitioned by a diaphragm pressed by a boost compensator spring, and the reduction of the diaphragm by the boost pressure operates a control rack via an operating member and a foot lever. The amount of fuel injected was controlled to increase or decrease.

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. Equilibrate. Further, an actuating member 16 is pressed against the push rod 13 by a starting increase spring 17. One end of a lever lever 18, which is supported by a pivot shaft 18a, comes into contact with the operating member 16, and the other end contacts a stopper 1 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 9b.

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
It operates in the direction of compressing a′. However, since the rotational speed of the diesel engine 10 is low and the amount of exhaust gas supplied to the exhaust gas turbine 20a of the turbocharger 20 is small, the boost pressure by the compressor 20b is low, so that the boost pressure is lower than the pressure chamber 1.
Even if the boost pressure is supplied to the diaphragm 1, it is lower than the set pressure of the boost compensator spring 15.
4 could not be lowered. In such a case, since the diaphragm 14 is not pushed down, the actuating member 16 also does not fall, and no matter how fully the driver depresses the accelerator pedal, the stopper 19b
Because the control rack 19 stopped and did not move at the position where it abutted against the lever 18, 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 the starting increase spring 17, the diaphragm 14 is compressed.
The actuating member 16 is lowered and the foot lever 18
rotation (clockwise direction) and stopper 1
9b is released, and the control rack 19 is now moved in the direction of increasing the fuel injection amount.

Therefore, according to Figure 2, the engine speed Ne
When the increase/decrease in fuel injection amount is shown by the positional relationship of the control rack, line a (imaginary line) shows the positional relationship of the control rack only by the governor body, and line b (broken line) shows the relationship between the control rack and the boost pressure of the boost compensator spring 15. It shows the positional relationship of the control rack in the boost compensator configured by balance, whereas line c (solid line) shows the position of the starting increase spring 17 in order to press the actuating member 16 into contact with the push rod 13. As shown in FIG. 1, this shows the positional relationship of the control rack when it is arranged in parallel with the boost compensator spring 15 to increase the amount of fuel injection.

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

Problems that the invention aims to solve However, in order to increase the torque when starting the engine, the amount of fuel injection has been increased in the past by using a boost compensator in which the starting increase spring is installed in parallel with the boost compensator spring. However, due to the structure of the engine, it was not possible to increase the fuel injection amount enough to produce the necessary torque in the extremely low rotational 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 will be within the range d. Therefore, in the extremely low speed rotation range (400 to 500 rpm), the amount of fuel injection is prevented from increasing due to structural functions, and moreover, positive displacement superchargers are used for the purpose of increasing torque in the extremely low speed rotation range of the engine. However, since the permissible stroke in which the diaphragm of the pressure chamber is compressed is limited due to its structure, with the conventional boost compensator installed as described above, it is difficult to inject a sufficient amount of fuel in the extremely low rotation speed range. However, there were disadvantages in that the torque could not be increased and starting performance could not be improved.

Therefore, in the present invention, the control rack, which had been stopped by the foot lever of the boost compensator to suppress the increase in fuel injection amount, is switched on at the same time as the control switch is turned on to switch to the positive displacement supercharger. Turbo supercharger and The purpose is to measure the increase in fuel injection amount in the extremely low speed rotation range of a positive displacement supercharged engine.

Means for Solving the Problems The present invention receives boost pressure from a turbo supercharger into a pressure chamber partitioned by a diaphragm pressed by a boost compensator spring, and the pressure reduction of the diaphragm causes the diaphragm to increase the starting pressure. In a boost compensator that operates a control rack that is in contact with the other end of the foot lever by means of an actuating member pressed by a spring and a foot lever that is in contact with the actuating member at one end to increase or decrease the amount of fuel injection. Depending on the engine speed and load, the controller will operate the positive displacement turbocharger operation switch in the extremely low speed range.
At the same time as it is turned on, the solenoid valve opens,
A displacement type that uses an actuator using air pressure from a separately owned air source to release the control rack that has been stopped by the foot lever and makes it free, making it possible to increase the amount of fuel injection based on the amount of depression of the accelerator pedal. This is a boost compensator for supercharged engines.

Function Therefore, the present invention is capable of increasing torque in the extremely low rotational speed range of the engine by switching from a turbo supercharger to a positive displacement supercharger under the control of a controller based on the engine speed and load. When the solenoid valve is opened at the same time as the operation switch is turned ON, air pressure from a separately owned air source operates the actuator, and the boost from the turbo supercharger is generated by the operation of the actuator. The diaphragm was pushed down by the pressure, and the foot lever, which had been stopped at one end by contacting the operating member that was being operated, was rotated, and the control rack, which had been stopped by the stopper at the other end of the foot lever, was rotated. is released and becomes free, and the control rack moves its other end in the direction of increasing the amount of fuel injection in accordance with the amount of depression of the accelerator pedal, which is connected to one end of the control rack together with the governor body. Sufficient fuel injection amount is increased immediately in response to aircraft operation. and,
Torque will be increased.

Embodiment Hereinafter, an embodiment of the boost compensator of the present invention will be explained based on the drawings. As shown in FIG. The boost compensator 1 operates to draw air into the diesel engine and receives the boost pressure in the pressure chamber 2, and the diaphragm 4 is compressed by the boost pressure to operate the operating member 6 and control rack 9. The boost compensator has a controller 33 that turns on and off the operation of the positive displacement supercharger 34 depending on the engine speed and load,
The controller operates the positive displacement turbocharger.
The actuator 32 has a solenoid valve 31 that opens so that the actuator 32 is actuated by air pressure from a separate air source 30 existing in the truck or the like when turned on. When the control rack 9 is brought into contact with and stopped, the control rack 9 is moved to its stopper 9.
The foot lever 8, which has been stopped at point b, has a piston rod 32a that is pivoted to the rotation axis pin 8b of the foot lever 8 through a long hole 32a', which rotates the stopped state so as to be forcibly released by the operation of the actuator 32. .

The pressure chamber 2 of the boost compensator is partitioned by a diaphragm 4 pressed by a boost compensator spring 5, and the diaphragm is provided with a push rod 3, which is disposed in parallel with the boost compensator spring 5. The actuating member 6 is pressed into contact with a starting increasing spring 7. One end of a foot lever 8, which is supported by a pivot 8a, is brought into contact with the operating member 6, and the other end of the foot lever 8 is a control rack that operates a plunger mechanism (not shown) that controls the increase and decrease of the fuel injection amount. 9
The stopper 9b is in contact with the stopper 9b.

Furthermore, 9a is a cancel mechanism;
a' is a spring, and 9a'' is an actuation bar connected to an accelerator pedal and a governor body (not shown).

Therefore, when the driver depresses the accelerator pedal to increase the torque, the operating bar 9a'' is activated, but the stopper 9b of the control rack 9 comes into contact with the foot lever 8 and is stopped, compressing the spring 9a' of the cancel mechanism 9a. As the engine speed increases, the diaphragm 4 pressed by the boost compensator spring 5 is compressed in the pressure chamber 2 which receives boost pressure from the turbo supercharger, and the diaphragm 4 is compressed by the starting booster spring 7. The actuating member 6 which is pressed into contact with the push rod 3 provided at rotational direction), thereby allowing the foot lever 8
The control rack 9, which was stopped by the stopper 9b at the other end, is moved by the force of the spring 9a' compressed by the cancel mechanism 9a, and the operation of the control rack 9 increases the amount of fuel injection. Ru.

However, since the boost pressure is low in the extremely low rotational speed range of the engine, the control rack 9 is activated by lowering the diaphragm 4 with the boost pressure and operating the actuating member 6 and lever 8 to increase the amount of fuel injected. It didn't reach that point.

Furthermore, even if the control rack 9 operates to increase the fuel injection amount, the permissible stroke of the diaphragm 4 of the pressure chamber 2 is until it reaches the bottom of the boost compensator case 1, and no further increase is possible. The operation did not occur.

Therefore, in order to increase the torque, we switched to the positive displacement supercharger 34, and even with that switch, the control rack 9 was not activated due to the low boost pressure and the permissible stroke of the diaphragm 4, and the amount of fuel injection could not be increased. To prevent this from running out, the positive displacement supercharger 34 is turned ON by the controller 33 depending on the engine speed and load, and at the same time the solenoid valve 31 is opened, so that air pressure from a separately owned air source 30 is applied to the actuator 32. The lever 8, which had stopped the control rack 9 by the piston rod 32a, is forcibly rotated, and the contact with the stopper 9b of the control rack is released, and the control rack 9 is stopped.
The operation becomes free and the amount of fuel injection can be increased according to the amount of depression of the accelerator pedal.

The elongated hole 32a' of the piston rod 32a has an allowable stroke length that allows the lever 8 that contacts and presses the actuating member 6 to operate under the pressure of the diaphragm 4 of boost pressure, and also adjusts the stroke of the actuator 32. By doing so, it is also possible to determine the amount of movement of the control rack 9 and determine the maximum fuel injection amount.

If the above state is shown in a drawing regarding the relationship between the control rack position and the engine speed, the fourth
It will look like the figure.

The a line (imaginary line) shows the positional relationship of the control rack based only on the governor body, and the b line (broken line) shows the positional relationship of the control rack 9 in the boost compensator constituted by the balance of the boost compensator spring with respect to the boost pressure. Line c (solid line) shows the positional relationship of the control rack 9 by the boost compensator in which the starting increase spring 7 is arranged in parallel with the boost compensator spring 5, and the line e (three-dot chain line) shows the state in which the increase in capacity is increased by pressing the accelerator pedal. This shows the positional relationship of the control racks. The range d shown in the figure is the increased amount due to the provision of the starting increase spring 7 in parallel with the boost compensator spring 5, and indicates the operating range of the boost compensator, and the range f shown in the figure is a positive displacement type in the extremely low speed rotation range. This shows a control rack position state in which the supercharger 34 is switched to operation and the fuel injection amount is increased by the amount of depression of the accelerator pedal.

Therefore, in a diesel engine with a positive displacement supercharger as described above, as shown in FIG. It becomes possible to increase the range i from the line (broken line) to the line h (solid line).

Effects of the invention As a result of the above, the present invention makes it possible to simultaneously obtain a fuel injection amount corresponding to the amount of depression of the accelerator pedal when the positive displacement supercharger is turned on depending on the engine speed and load. Since it is possible to increase the amount in the low speed rotation range and at the time of starting, and the torque can be significantly increased, starting performance and acceleration performance are improved.

[Brief explanation of the drawing]

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 case,
2,12...Pressure chamber, 3,13...Push rod, 4,14...Diaphragm, 5,15...Boost compensator spring, 6,16...
Operating member, 7, 17...starting increase spring,
8, 18... Foot lever, 8a, 18a... Pivot, 8b... Rotating pivot pin, 9, 19... Control rack, 9a, 19a... Cancel mechanism, 9a', 19a'... Spring, 9a'', 19
a″...operating bar, 9b, 19b...stopper,
10... Diesel engine, 20... Turbo supercharger, 20a... Exhaust gas turbine, 20b...
Compressor, 30... Air source, 31... Solenoid valve, 32... Actuator, 32a... Piston rod, 32a'... Long hole, 33... Controller, 34... Positive displacement supercharger.

Claims (1)

[Scope of utility model registration request] Boost pressure from a turbo supercharger is received in a pressure chamber partitioned by a diaphragm pressed by a boost compensator spring, and the pressure of the diaphragm is applied to the diaphragm by a starting increase spring, the actuating member being pressed, and the actuating member. In a boost compensator, a control rack that is in contact with the other end of the foot lever is actuated by a foot lever that is in contact with the other end of the foot lever to increase or decrease the amount of fuel injection. It has a controller that turns on and off the operation of the control rack, and an actuator that is actuated via a solenoid valve by air pressure from a separately owned air source that releases the contact stop caused by the foot lever of the control rack. A positive displacement supercharger characterized in that, at the same time as the controller turns on the solenoid valve, the control rack is released by the actuator, making it possible to increase the amount of fuel injection in accordance with the amount of depression of the accelerator pedal. Boost compensator for engine.