JPH1089081A - Supercharged pressure controller for variable capacity turbocharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suffice an actuator by one, dminish a space occupied by the actuator, and reduce a mounting space to a vehicle, by connecting a rod for driving the opening/closing of a waste gate valve and a link tlor driving the opening/ closing of a variable nozzle to the rod of a single actuator. SOLUTION: A rod 2 for driving the opning/closing of a variabl nozzle is movable in a direction perpendi cular to an actuator rod. When the rod 2 is moved in a VC direction, the variabl.e nozzle is rotated on an opening small side (closing side),and when the rod 2 is moved in a VO direction, the variable, nozzle is rotated on an opening large side (opening side). A link 7 for driving the opening/closing of a waste gate valve is rotated within a flat surface including rods l, 2. When the link 7 is move in a WC direction, the waste gate valve is rotated on the opening small side (clposing side), and when the link 7 is moved in a WO direction, the waste gate valve is rotated on the opening large side (opening side). A groove 6 is formed in the rod l, and a pin 2a connected to the rod 2 is slidably fitted in this groove 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a supercharging pressure control device for a variable displacement turbocharger.

[0002]

2. Description of the Related Art Turbocharger supercharging pressure control includes a method using a variable nozzle, a method using a wastegate valve, and a method using both of them. When controlling the supercharging pressure with the variable nozzle, change the opening of the variable nozzle to change the exhaust gas speed flowing into the turbine wheel to control the turbine rotation speed, and when controlling the supercharging pressure with the wastegate valve, The work amount of the turbine is controlled by changing the opening of the wastegate valve and changing the amount of exhaust gas that bypasses the turbine. Japanese Utility Model Laid-Open Publication No. 61-159627 discloses that in supercharging pressure control of a variable capacity turbocharger having a waste gate valve and a variable nozzle, the variable nozzle is prevented from opening from an opening at which turbine efficiency sharply decreases. After the state, the opening and closing of the waste gate valve and the variable nozzle are controlled so that the waste gate valve is opened. In order to perform the opening / closing control, separate actuators are required for opening / closing the wastegate valve and the variable nozzle.

[0003]

However, since two actuators are provided, it is difficult to secure a space when the engine with the supercharger is mounted on the vehicle. In addition, two cases are required, and the cost is inevitably increased. An object of the present invention is to provide a variable-capacity turbocharger supercharging pressure control device that is advantageous in terms of mounting space in a vehicle and cost in a variable-capacity turbocharger including a wastegate valve and a variable nozzle. .

[0004]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a variable displacement turbocharger having a wastegate valve and a variable nozzle. It comprises a supercharging pressure control device for a variable capacity turbocharger in which an opening / closing drive rod and a variable nozzle opening / closing drive link are connected. Then, the link for the wastegate valve opening / closing drive link and the connecting structure between the variable nozzle opening / closing drive rod and the actuator rod are structured such that only the variable nozzle is opened in a predetermined engine speed range and only the wastegate valve is opened in a higher speed range. There is.

[0005] In the above device, the variable nozzle and the waste gate valve are opened and closed by one actuator.
Conventionally, two actuators are required and only one actuator is required.
As a result, the space occupied by the actuator is reduced, which is advantageous in terms of mounting space in a vehicle and cost.

[0006]

1 and 2 show a first embodiment of the present invention. FIGS. 3 and 4 show a second embodiment of the present invention.
Shows an overall configuration applicable to both the first and second embodiments of the present invention. Portions common to the first embodiment and the second embodiment are denoted by the same reference numerals in both embodiments. First, the configuration common to the first and second embodiments of the present invention will be described with reference to, for example, FIG. 1, FIG. 2, (or FIG. 3, FIG. 4), and FIG.
This will be described with reference to FIG.

[0007] As shown in Fig. 5, the supercharging pressure control device for a variable displacement turbocharger according to the embodiment of the present invention is a supercharging pressure control device for a variable displacement turbocharger having a waste gate valve and a variable nozzle. And a device in which a wastegate valve opening / closing drive link 7 and a variable nozzle opening / closing drive rod 2 are connected to the rod 1 of the single actuator 3.

The turbocharger 20 has a turbine 21 and a compressor 22. The turbine 21 is disposed in an engine exhaust passage, and a rotor inside the turbine 21 is rotated by the energy (speed energy and thermal energy) of the engine exhaust gas. Reference numeral 22 is disposed in the engine intake passage, and is driven by the turbine 21 to compress intake air and supercharge the engine, thereby increasing engine torque and engine output. The supercharging pressure (compressor outlet pressure) control controls the opening degree of a variable nozzle provided at the rotor inlet of the turbine 21 and is installed in a bypass passage provided to bypass the turbine 21 with respect to the engine exhaust passage. This is achieved by controlling the opening of the wastegate valve.

In FIG. 5, the variable nozzle opening / closing drive rod 2 is movable in a direction orthogonal to the actuator rod 1, and when the variable nozzle opening / closing drive rod 2 moves in the VC direction, the variable nozzle opens at a small opening (closed side). ), And when the variable nozzle opening / closing drive rod 2 moves in the VO direction, the variable nozzle rotates toward the larger opening (opening side). When the opening degree of the variable nozzle is reduced and narrowed, the flow velocity of the exhaust blown to the turbine rotor through the variable nozzle increases, the turbine rotation speed increases, the supercharging pressure increases, and the same exhaust gas amount is obtained. When the opening degree of the variable nozzle becomes large, the turbine rotation speed decreases and the supercharging pressure decreases. The wastegate valve opening / closing drive link 7 is connected to the actuator rod 1.
When the waist gate valve opening / closing drive link 7 is rotated in the WC direction in a plane that is the same as or parallel to the plane including the variable nozzle opening / closing drive rod 2 and the waste gate valve opening small side (closed side). When the waist gate valve opening / closing drive link 7 moves in the WO direction, the waist gate valve opens to a large opening (open side).

[0010] In FIG. 1, the actuator 3 moves the rod 1 from the casing as the engine speed increases.
The actuator has a large protrusion amount. For example, a positive pressure (for example, supercharging pressure) is introduced into the diaphragm chamber 3a, and when the engine speed increases and the supercharging pressure becomes large, the diaphragm 3b pushes the diaphragm 3b against the urging force of the spring 3c to push the rod 1 into the casing. Move to the side protruding from (When using a negative pressure, a negative pressure is introduced into the chamber on the side opposite to 3a.)

Waste gate valve opening / closing drive link 7
As shown in FIGS. 1 and 2 (or as shown in FIGS. 3 and 4), the connecting structure between the variable nozzle opening / closing drive rod 2 and the actuator rod 1 has a predetermined engine speed range b (FIG. 1). , FIG. 2, FIG. 3, and FIG. 4, a, b, c, A, B, and C in any of the figures are a, b, c, A, and
1 and 4, the variable nozzle is abbreviated as VN, and the waste gate valve is abbreviated as WGV).
Is set so that only the waste gate valve is opened in the variable nozzle fully opened state, and both the waste gate valve and the variable nozzle are closed on the lower rotational speed region a than the region b.

The connecting structure 4 between the variable nozzle opening / closing drive rod 2 and the actuator rod 1 is as follows. A groove (including a slot) 6 is formed in the rod 1, and a pin 2 a connected to the variable nozzle opening / closing drive rod 2 is slidably fitted in the groove 6. Groove 6
In FIG. 1, a first portion 6a extending in the axial direction of the rod 1, a second portion 6b extending upward and toward the VO side while bending from an upper end of the first portion 6a, and a second portion 6b
And a third portion 6c extending upward from the upper end of the rod 1 in a direction parallel to the axial direction of the rod 1.

In the low engine speed region a shown in FIG.
The pin 2a of the variable nozzle opening / closing drive rod 2 is the rod 1
And is slidably fitted with the first portion 6a of the groove 6 of FIG. In this state, the variable nozzle is in a closed state. In the engine speed region b (the rotation speed is higher than the region a) in FIG. 2, the pin 2a of the variable nozzle opening / closing drive rod 2 in FIG. I agree. FIG.
When the state changes from A to B, the variable nozzle opening / closing drive rod 2 is moved to the VO side to open the variable nozzle from closed to open. In FIG. 2, the pin 2 a of the variable nozzle opening / closing drive rod 2 is slidably fitted with the third portion 6 c of the groove 6 of the rod 1 in the engine high rotation speed region c (the rotation speed is higher than the region b) in FIG. 2. I agree. In this state, the variable nozzle remains open.

In FIG. 2, at the boundary point A between the rotation speed ranges a and b,
The positional relationship between the pin 2a of the variable nozzle opening / closing drive rod 2 and the groove 6 of the rod 1 is in the state of A in FIG. At the boundary point B between the rotational speed ranges b and c in FIG. 2, the positional relationship between the pin 2a of the variable nozzle opening / closing drive rod 2 and the groove 6 of the rod 1 is as shown in FIG. At a point C which is away from B in the rotational speed range c in FIG. 2, the positional relationship between the pin 2a of the variable nozzle opening / closing drive rod 2 and the groove 6 of the rod 1 is in the state of C in FIG.

Waste gate valve opening / closing drive link 7
The connection structure 5 between the actuator and the actuator rod 1 is as follows. In the engine speed range a and the speed A in FIG.
Is located at a position A in FIG. 1 (a rotation position at which the wastegate valve is closed), and is connected to the actuator rod 1 at that position. In the engine speed region b and the engine speed B in FIG. 2, the wastegate valve opening / closing drive link 7 is located at the position B in FIG. It is linked to Engine speed range c in FIG.
At the rotation speed C, the wastegate valve opening / closing drive link 7 is located at the position C shown in FIG. 1 (a rotation position where the wastegate valve is opened), and is connected to the actuator rod 1 at that position. When the wastegate valve opening / closing drive link 7 rotates from the position B to the position C in FIG. 1, the wastegate valve is changed from the closed state to the open state, and the variable nozzle remains open at that time.

Next, a structure specific to each embodiment of the present invention (the first embodiment and the second embodiment are different in the connection structure 5 between the wastegate valve opening / closing drive link 7 and the actuator rod 1). . In the connection structure 5 between the wastegate valve opening / closing drive link 7 and the actuator rod 1 according to the first embodiment of the present invention, the wastegate valve opening / closing drive link 7 has a groove (slot) formed in the link 7 in the axial direction. Pin 7a fitted to 7c
Are connected via An axially extending groove (including a slot) 8 is formed in the actuator rod 1, and a pin 7 a is slidably fitted in the groove 8.

In the rotational speed regions a and b and the rotational speed A in FIG. 2, there is a gap between the pin 7a and the upper end point of the groove 8 as shown in the state of FIG. Link 7 does not rotate around the fulcrum 7b. At the rotational speed B in FIG. 2, the pin 7a contacts the upper end point of the groove 8, as shown in the state of FIG. In the rotation speed region c and the rotation speed C of FIG. 2, as shown in the state of FIG. 1C, the pin 7a is in contact with the upper end point of the groove 8, and the wastegate valve opening / closing drive link 7 is connected to the fulcrum 7b. Rotate around.

However, in the first embodiment, in the rotation speed regions a and b and the rotation speed A in FIG. 2, as shown in the state A in FIG. There is a gap,
The wastegate valve opens slightly due to the back pressure of the exhaust gas, and the exhaust gas may leak a little through the wastegate valve. If the exhaust gas leaks, the boost pressure increasing performance may slightly decrease in the rotation speed regions a and b. The second embodiment of the present invention described below solves this problem.

In the connection structure 5 between the wastegate valve opening / closing drive link 7 and the actuator rod 1 according to the second embodiment of the present invention, the wastegate valve opening / closing drive link 7 is, as shown in FIGS. The link 7 is connected to the actuator rod 1 via a pin 7a fitted into a groove (including a slot) 7c formed in the link 7, and is rotated around the fulcrum 7b by the actuator rod 1. The wastegate valve 12 rotates in conjunction with the rotation of the wastegate valve opening / closing drive link 7, and opens and closes the bypass passage 11 that bypasses the turbine. The wastegate valve 12 is a fan-shaped valve.

The arc length v of the waste gate valve 12 is longer than the arc length p of the bypass passage 11, and the pin 2a of the variable nozzle opening / closing drive rod 2 is inserted into the first groove 6 of the rod 1.
And the second portion 6a, 6b, the wastegate valve 12 rotates in the rotation direction. The amount of rotation, the arc length V of the wastegate valve, and the arc length of the bypass passage 11 at this time. By making the difference between P equal, the closed state of the bypass passage 11 of FIGS. 3A and 3B is maintained.
Therefore, when the wastegate valve 12 is closed, leakage of exhaust gas is reduced, the turbine speed can be increased, and the supercharging pressure can be further increased. Note that 13
Is a stopper for preventing the wastegate valve 12 from rotating excessively.

Next, the operation will be described. The first of the present invention,
As an action common to the second embodiment, the single actuator rod 1 moves the variable nozzle opening / closing drive rod 2 and the wastegate valve opening / closing drive link 7. Although the variable nozzle opening / closing timing of the variable nozzle opening / closing drive rod 2 and the waist gate valve opening / closing timing of the waste gate valve opening / closing drive link 7 are different, the shapes of the grooves 6 and 8 are set as shown in FIG. In the engine speed region a, the variable nozzle closing and the waste gate valve closing operation are performed by setting the shape and the positional relationship between the groove 6, the valve 12, and the passage 11 as shown in FIG. In the engine speed region b, the variable nozzle performs the operation of closing and opening the waste gate valve, and in the engine speed region c, the variable nozzle performs the operation of closing and opening and the waste gate valve closing and opening, respectively. Can be made. By using a single actuator 3, the space occupied by the actuator is smaller than in the conventional case where two actuators 3 are provided.
Mounting a supercharged engine including the actuator 3 on a vehicle is easy in terms of space and work. In addition, the number of casings, diaphragms, springs, etc. constituting the actuator is reduced to half that of the conventional case, and the cost is reduced.

As a function peculiar to the first embodiment of the present invention, in the engine speed regions a and b, the position of the wastegate valve opening / closing drive link 7 is positively held while the wastegate valve is closed. Since the force of the opening and closing mechanism is not applied to the opening / closing mechanism, the wastegate valve causes the gas flowing through the scroll of the turbine housing,
Although there is a possibility that the boosting pressure slightly rises, a sufficient boosting pressure rising effect can be obtained even if the boosting pressure is slightly increased because the variable nozzle has a large boosting pressure rising effect. In FIG.
The dotted line indicates the boost pressure rise only by the conventional wastegate valve (a, b, when the wastegate valve is closed and opens at point B), and the solid line is variable with the wastegate valve according to the first embodiment of the present invention. A case is shown in which the variable nozzle is opened in the area b and the waste gate valve is opened in the area c using both the nozzles.

As an operation unique to the second embodiment of the present invention, in the engine speed ranges a and b, the wastegate valve 12 keeps the bypass passage 11 completely closed.
As shown in the figure, in the engine speed regions a and b (when the wastegate valve 12 is closed), the leakage of the exhaust gas to the bypass passage 11 is smaller than in the first embodiment, the turbine speed is increased, and therefore the supercharging pressure is increased. Is raised, and the rising performance is improved. FIG. 4 also shows, for comparison, the case of the first embodiment of the present invention and the case of performing supercharging pressure control only with a conventional wastegate valve.

[0024]

According to the device of the first aspect, the wastegate valve opening / closing drive link and the variable nozzle opening / closing drive rod are connected to the single actuator rod.
Conventionally, two actuators are required and only one actuator is required.
As a result, the space occupied by the actuator is reduced, which is advantageous in terms of mounting space in a vehicle and cost.

[Brief description of the drawings]

FIG. 1 is a schematic front view of a variable displacement turbocharger according to a first embodiment of the present invention in each operating state of a supercharging pressure control device.

FIG. 2 is a characteristic diagram of supercharging pressure / engine speed of a supercharging pressure control device for a variable displacement turbocharger according to a first embodiment of the present invention.

FIG. 3 is a schematic front view of a variable-capacity turbocharger according to a second embodiment of the present invention in each operating state of a supercharging pressure control device.

FIG. 4 is a characteristic diagram of supercharging pressure / engine speed of a supercharging pressure control device for a variable displacement turbocharger according to a second embodiment of the present invention.

FIG. 5 is an overall view of a supercharging pressure control device for a variable displacement turbocharger, which can be applied to both the first embodiment and the second embodiment of the present invention, as viewed from the lower surface of the engine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Actuator rod 2 Variable nozzle opening / closing drive rod 3 Actuator 6 Groove 7 Waste gate valve opening / closing drive link 8 Groove 11 Bypass passage 12 Est gate valve 20 Turbocharger 21 Turbine 22 Compressor

Claims (1)

[Claims] 1. A supercharging pressure control device for a variable displacement turbocharger having a wastegate valve and a variable nozzle, wherein a single actuator rod includes a wastegate valve opening / closing drive link and a variable nozzle opening / closing drive rod. A supercharged pressure control device for a variable-capacity turbocharger, which is connected.