JPS626257Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a variable nozzle control device for a turbocharger, which is provided with an on-off valve mechanism at an inlet for introducing exhaust gas into a turbine.

Generally, a turbo supercharger is made up of a turbine placed in the exhaust passage of the engine and a compressor placed in the intake passage of the engine. The turbine is configured to rotate, and as the turbine is driven, a compressor mounted coaxially with the turbine is rotated, thereby increasing the filling efficiency of fuel supplied into the engine.

By the way, in this type of engine, when the accelerator is depressed, that is, when the engine load is increased, the flow rate of exhaust gas introduced from the engine into the turbine is small, so the rotational speed of the turbine is relatively low, and the compressor is Boost pressure was getting low. As a result, the startup speed of the turbocharger was slow, resulting in poor engine response. In addition, in the high engine speed range where the engine speed is high, the turbine rotates at high speed, so
There was also a problem that the engine brake was difficult to apply.

This idea was created in consideration of the above circumstances, and its purpose is to speed up the start-up of the turbocharger when the engine load increases, improve engine response, and effectively apply engine braking. An object of the present invention is to provide a variable nozzle control device for a turbo supercharger that can be operated to control the nozzle of a turbocharger.

An embodiment of this invention will be described below with reference to the drawings. In FIG. 1, 1 is a turbine of a turbocharger. The turbo supercharger is composed of the turbine 1, which is disposed in the exhaust passage of the engine's exhaust gas, and a compressor, which is disposed in the intake passage of the engine. As the turbine 1 is driven, a compressor mounted coaxially with the turbine 1 is driven to rotate, thereby increasing the filling efficiency of the air-fuel mixture supplied into the engine. Furthermore, an on-off valve mechanism 2 is disposed at the exhaust gas inlet of the turbine 1 . This on-off valve mechanism 2
is formed by a movable ring 3, a plurality of movable vanes 4, and a plurality of connecting rods 5 connecting each movable vane 4 to the movable ring 3. Each of the movable vanes 4 is rotatably provided around a pin 6, and as the movable ring 3 rotates clockwise in FIG. 1, each movable vane 4 moves around a pin 6. At the same time as the movable ring 3 rotates counterclockwise, each movable vane 4... is rotated clockwise around the pin 6...
It is designed to be rotated counterclockwise around . Further, this on-off valve mechanism 2 is adapted to be driven by a drive mechanism 7. This drive mechanism 7 includes a cylinder 8 which is an actuator, a first cylinder 8,
Second electromagnetic switching valves 9, 10 and air tank 1
It is formed by 1. Inside the cylinder 8, first and second pistons 12 and 13 are disposed, as well as first and second stoppers 1.
4 and 15 are provided, respectively. The first stopper 14 is attached to an intermediate portion inside the cylinder 8, and first and second pressure chambers 16 and 17 are respectively formed inside the cylinder 8 by the first stopper 14. Further, the second stopper 15 is provided protrudingly from the end face on the second pressure chamber 17 side. A first piston 12 and a second piston 13 are arranged inside the first pressure chamber 16 and the second pressure chamber 17, respectively. Also, the first
The piston rod 12a of the piston 12 is inserted into an insertion hole 18 provided at the center of the first stopper 14, and with the piston rod 12a guided by the insertion hole 18, the first piston 1 is inserted.
2 performs reciprocating motion within the first pressure chamber 17. Furthermore, the piston rod 13a of the second piston 13 is protruded to the outside through an insertion hole 19 provided in the end face of the cylinder 8 on the second pressure chamber 17 side, and is connected to the movable ring 3 through a connecting member 20. connected. Further, a coil spring 21 is wound around the piston rod 13a of the second piston 13. The second piston 13 is capable of reciprocating movement within the second pressure chamber 17 and is normally held pressed against the first stopper 14 by the biasing force of the coil spring 21. ing. The cylinder 8 also has a first vent hole 22 on the end face on the first pressure chamber 16 side.
is formed. Furthermore, the first stopper 14
has an opening 23a facing the first pressure chamber 16 side.
and an opening 23 facing the second pressure chamber 17 side.
b are formed respectively. The first vent 22 of the cylinder 8 has one end of the first air pipe 24, and one opening 23b of the first stopper 14.
One end of the second air supply pipe 25 is connected to each of the two ends, and an exhaust pipe is connected to the other opening 23a of the first stopper 14. Further, the other end of the first air supply pipe 24 is connected to the first electromagnetic switching valve 9, and the other end of the second air supply pipe 25 is connected to the second electromagnetic switching valve 10, respectively. Further, the first electromagnetic switching valve 9 has an exhaust pipe 26 and a third air supply pipe 27, and the second electromagnetic switching valve 10 has an exhaust pipe 28.
and a fourth air pipe 29 are connected to each other. Then, the first solenoid switching valve 9 causes the first air pipe 24 and the exhaust pipe 26 to communicate with each other, or the first air pipe 24 and the third air pipe 27 to communicate with each other. Along with the switching operation,
The second air supply pipe 25 is controlled by the second electromagnetic switching valve 10.
The switching operation is performed such that the air pipe 25 and the exhaust pipe 28 are in communication with each other, or the second air pipe 25 and the fourth air pipe 29 are in communication with each other. Further, the third and fourth air supply pipes 27 and 29 are communicated with each other, and are supplied with air from the air tank 11, respectively. Then, each of the first and second electromagnetic switching valves 9, 10
are the first and second air pipes 24, 25 and each exhaust pipe 2.
6 and 28, the second piston 13 is held at the reference position pressed against the first stopper 14 by the biasing force of the coil spring 21. It's summery. Further, the first solenoid valve 9 is connected to the first air pipe 24
At the same time, the second electromagnetic switching valve 10 is switched to a state where the third air supply pipe 27 and the third air supply pipe 27 are communicated with each other.
When the air supply pipe 25 and exhaust pipe 28 are switched to communicate with each other, air is supplied from the air tank 11 into the first pressure chamber 16 via the third and first air supply pipes 27 and 24. As shown in FIG. 2, the first piston 12 is moved to the first stopper 1 by
4, the second piston 13 is moved by the piston rod 12a of the first piston 12 against the biasing force of the coil spring 21, and the second piston 13 is moved between the first and second stoppers 14 and 15. It is adapted to be held in a first displacement position.
Further, the first and second electromagnetic switching valves 9 and 10 switch the first and second air pipes 24 and 25 to the third and fourth air pipes 27 and 29, respectively. When operated, air is supplied from the air tank 11 into the first pressure chamber 16 via the third and first air supply pipes 27, 24, and the fourth,
Since air is also supplied into the second pressure chamber 17 via the second air supply pipes 29 and 25, the second piston 13 is moved to the second stopper 15 as shown in FIG.
It is adapted to be held in a second displacement position pressed against the. Therefore, the second piston 1
3 is adapted to be moved to three stages, a reference position, a first displacement position, and a second displacement position, based on switching operations of the first and second electromagnetic switching valves 9 and 10. When the piston 13 of No. 2 is held at the reference position, the movable link 3 and each movable vane 4 are held in the normal state _A3 in which the opening area of the exhaust gas inlet of the turbine 1 is wide open.
When the second piston 13 is moved to the second displacement position, the moving operation of the second piston 13 causes the movable ring 3 to rotate clockwise in FIG. ... are respectively rotated clockwise around pin 6..., and turbine 1
Throttle condition where the opening area of the exhaust gas inlet is narrowed down.
When the second piston 13 is held at A ₁ and moved to the first displacement position, the movable ring 3 and each movable vane 4 move to the intermediate state as the second piston 13 moves. The opening area of the exhaust gas inlet of the turbine 1 is maintained at an intermediate throttle state _A2 , which is between the normal state _A3 and the throttle state _A1 .

On the other hand, 30 is the accelerator pedal of the car body, 3
1 is a load detection sensor 32 that detects the engine load from the accelerator opening degree l of the accelerator pedal 30;
is a rotation speed detection sensor that detects the rotation speed N of the engine. Output signals from these load detection sensor 31 and rotation speed detection sensor 32 are input to a controller 33. This controller 33 controls the drive mechanism 7 according to the engine rotation speed N and the engine load. That is, as shown in FIG. 4, during low-load operation when the accelerator opening degree l is less than the first set value _l1 and the engine load is small, the first and second electromagnetic switching valves 9 and 10 are switched to the first and second positions. The air pipes 24, 25 and the third and fourth air pipes 27, 29 are switched to communicate with each other, and the second piston 13 is switched to the third
Move each movable vane 4 to the second displacement position shown in the figure to hold it in the throttle state _A1 , and when the accelerator opening l reaches the first set value _l1 , the first and second Each electromagnetic switching valve 9, 10 is connected to each of the first and second air pipes 2.
4, 25 and the respective exhaust pipes 26, 28 are switched to communicate with each other, and the second piston 13 is switched to the first
Move each movable vane 4 to the reference position shown in the figure.
... is controlled to be maintained in the normal state _A3 . Also, the engine rotation speed N is the first
If the accelerator opening l becomes larger than the second set value _l2 in a state of a low rotational speed range lower than the set value _N1, the first and second electromagnetic switching valves 9 and 10 are switched to the first , the second air pipes 24, 25 and the third and fourth air pipes 27, 29 are switched to communicate with each other, and each movable vane 4 is held in the throttle state _A1 . There is. Further, the engine speed N is set to a second set value higher than the first set value _N1 .
Accelerator opening l in the middle rotation speed range lower than N ₂
becomes larger than the second set value _l2 , the first electromagnetic switching valve 9 is switched to a state where the first air supply pipe 24 and the third air supply pipe 27 are communicated with each other, and the second The electromagnetic switching valve 10 is switched to a state where the second air supply pipe 25 and the exhaust pipe 28 are communicated with each other, and each movable vane 4 is held in an intermediate throttle state _A2 .

Therefore, in the case of the above configuration, the turbine 1
The opening area of the exhaust gas inlet of the turbine 1 is switched in stages (discontinuously) into three stages: minimum state, intermediate throttle state, and maximum open normal state. For example, the opening area of the exhaust gas inlet of the turbine 1 can be quickly switched to the minimum state at the same time as the accelerator pedal 30 is turned off. When the accelerator opening l is low and the engine load is small, each movable vane 4 is held in the throttle state _A1 , so that the exhaust gas introduced into the turbine 1 side via each movable vane 4 is The flow rate can be significantly increased compared to conventional methods. Furthermore, the exhaust gas can be effectively blown onto the turbine 1 by each movable vane 4 . Therefore, when the accelerator is depressed, that is, when the engine load increases, the turbine 1
The rotation speed of the compressor can be increased, and the boost pressure of the compressor can be increased. Therefore,
It is possible to accelerate the start-up of the turbo supercharger, further increase the filling efficiency of fuel supplied to the engine, and improve the responsiveness of the engine. Also, with the engine running in a high rotation speed range, release the accelerator and adjust the accelerator opening l to the first level.
By reducing the setting value l to below ₁ , each movable vane 4 is controlled to switch to the aperture state _A1 .
The flow resistance of the exhaust gas introduced into the turbine 1 side via each movable vane 4 rapidly increases. Therefore, engine braking can be effectively applied. Furthermore, since the operation of the drive mechanism 7 of the on-off valve mechanism 2 that changes the area of the exhaust gas inlet of the turbine 1 is controlled by the controller 33, for example, the depression force of the accelerator pedal 30 is applied to the on-off valve mechanism 2. There is no fear that it will change depending on the driving state, and it is possible to prevent the pedal operation feeling of the accelerator pedal 30 from deteriorating as the depression operation force of the accelerator pedal 30 changes.

Note that this invention is not limited to the above embodiments. For example, the drive mechanism 7 may be hydraulic or electric. Furthermore, it goes without saying that various other modifications can be made without departing from the gist of the invention.

As explained above, according to this invention, the opening area of the exhaust gas inlet of the turbine is switched stepwise into three stages: the minimum state, the intermediate throttle state, and the maximum open normal state. It is possible to speed up the switching operation of the opening area of the exhaust gas inlet of the turbine, and by switching the opening area of the turbine exhaust gas inlet to the minimum state, the flow velocity of the exhaust gas flowing into the turbine is increased. This increases engine torque, making it possible to accelerate the start-up of the turbocharger when the engine load increases, such as during sudden acceleration, when the accelerator pedal is pressed down rapidly, improving engine responsiveness and improving acceleration performance. In addition to improving the feeling of acceleration, the opening area of the turbine exhaust gas inlet can be quickly switched to the minimum state even when the engine load is reduced, such as when operating the engine brake. It is possible to increase the flow resistance of exhaust gas flowing into the exhaust gas inlet of the engine, thereby effectively applying engine braking.

[Brief explanation of the drawing]

The figures show one embodiment of this invention. Figure 1 is a schematic diagram of the overall configuration, Figures 2 and 3 are schematic diagrams for explaining the operation of the drive mechanism, and Figure 4 is an engine rotation diagram. FIG. 4 is a relationship diagram showing the relationship among the number of gases, the opening degree of the accelerator, and the opening area of the inlet. DESCRIPTION OF SYMBOLS 1... Turbine, 2... Opening/closing valve mechanism, 7... Drive mechanism, 31... Load detection sensor, 32... Rotation speed detection sensor, 33... Controller.

Claims (1)

[Scope of utility model registration request] A turbine driven by exhaust gas discharged from an engine cylinder, an on-off valve mechanism disposed at the exhaust gas inlet of the turbine and varying the area of the inlet, and a valve mechanism that drives the on-off valve mechanism. A drive mechanism, a rotation speed detection sensor that detects the engine rotation speed, a load detection sensor that detects the engine load based on the accelerator opening degree, and output signals from the rotation speed detection sensor and the load detection sensor are inputted. The drive mechanism is controlled according to changes in engine rotation speed and engine load, and the accelerator opening is smaller than the first set value during low-load operation and the accelerator opening is larger than the first set value. During low-speed, high-load operation in which the value exceeds the first set value and the engine speed is lower than the first set value, the opening area of the inlet is kept at a minimum to increase the flow velocity of the exhaust gas flowing into the turbine. , when the accelerator opening is larger than the second set value and the engine speed is maintained between the first set value and a second set value higher than the first set value, A turbo supercharger characterized by comprising: a controller that maintains the opening area of the inlet in an intermediate throttle state, and otherwise switches the opening area of the inlet to a normal state in which it is opened to the maximum. Machine's variable nozzle control device.