JPH108978A - Supercharging pressure control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain the deterioration of a fuel consumption rate with the excessive increase of exhaust pressure during partial load by providing a nozzle vane at the inlet of a turbine for a turbo charger to vary an exhaust air passing area so that the opening of the nozzle vane can be controlled to be increased corresponding to the increase of supercharging pressure. SOLUTION: In a turbo charger which has a compressor in an intake passage 2 and a turbine 4 in an exhaust passage 3, a nozzle vane 5 is provided at the inlet of the turbine 4 to vary the area of a nozzle. In a low load conditions where supercharging pressure is below P0 and differential pressure between exhaust pressure and supercharging pressure is below P1 , the nozzle vane 5 is fully closed. When the differential pressure between exhaust pressure and supercharging pressure gets to P1 , the second push rod 7d of the second actuator 7 is displaced corresponding to the differential pressure to open the nozzle vane 5 via a link 8 and a push rod 9 and, when supercharging pressure gets to P0 , the first actuator 6 is operated to control the opening of the nozzle vane 5 to be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a supercharging pressure control device for an internal combustion engine.

[0002]

2. Description of the Related Art As a conventional supercharging pressure control device for an internal combustion engine, a description of a new model of a NISSAN Leopard F31 type vehicle (Nissan Motor Co., Ltd., February 1986, No. 549)
No. B-13).

[0003] This is a variable nozzle that controls the nozzle area in accordance with the operating conditions by opening a movable flap provided in a turbine nozzle portion in order to achieve both an improvement in torque at low speed and an increase in output at high speed. It has a mechanism.
In this system, the nozzle is fully closed until the supercharging pressure reaches a predetermined value, and the nozzle is opened when the supercharging pressure exceeds a predetermined value.

[0004]

However, when such supercharging pressure control is performed, since the nozzle is fully closed until the supercharging pressure reaches a predetermined value, the exhaust pressure reduces the supercharging pressure. There is a possibility that it will greatly exceed the fuel efficiency. In particular, in a diesel engine having a low exhaust gas temperature at a partial load, the fuel consumption may be deteriorated because it is necessary to increase the turbine pressure ratio by narrowing the nozzle opening area, that is, to increase the turbine pressure by increasing the exhaust pressure. .

For this reason, it is necessary to finely control the nozzle opening in accordance with the operating conditions.
By changing the rate at which the supercharging pressure introduced from the downstream of the compressor is released to the atmosphere (upstream of the compressor), the pressure introduced to the actuator that drives the variable nozzle is controlled. In order to perform the control, that is, the feedback control of the nozzle to the intermediate opening, a sensor for detecting the intake air amount and the supercharging pressure is required, and the system configuration is complicated.

The present invention has been proposed in view of the above-described problems of the prior art, and realizes supercharging pressure control according to engine operating conditions with a simple system configuration, and achieves fuel efficiency at a partial load due to a rise in exhaust pressure. The purpose is to suppress deterioration.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention has a nozzle vane for varying the exhaust passage area of a turbine inlet of a turbocharger, and a supercharging pressure chamber for introducing a supercharging pressure. A diaphragm-type first actuator driven by a pressure difference between the supercharging pressure and the atmospheric pressure, an exhaust pressure chamber into which the exhaust pressure at the turbine inlet is introduced, and a supercharging pressure chamber into which the supercharging pressure is introduced. A diaphragm type second actuator formed and driven by a differential pressure between the exhaust pressure and the supercharging pressure; a first push rod interlocked with the first actuator; and a second push rod interlocked with the second actuator.
With a push rod and a link supported at both ends,
The link and the nozzle vane are interlocked via a third push rod.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a configuration diagram of an embodiment of the present invention. First, the configuration will be described. A compressor (not shown) of a turbocharger is mounted in an intake passage 2 connected to an engine body 1, and a turbine 4 is mounted in an exhaust passage 3.
At the inlet of the turbine 4, there is provided a nozzle vane 5 having a variable nozzle area.

The supercharging pressure in the intake passage 2 downstream of the compressor is introduced into the supercharging pressure chamber 6a of the first actuator 6 through the introduction pipe 10a. An atmospheric pressure chamber 6c is formed on the opposite side of the supercharging pressure chamber 6a via a diaphragm 6b. FIG. 2 shows the relationship between the supercharging pressure in the supercharging pressure chamber 6a and the displacement (downward in FIG. 1) of the first push rod 6d interlocked with the diaphragm 6b.

The second actuator 7 has an exhaust pressure chamber 7a through which the exhaust pressure in the exhaust passage 3 upstream of the turbine 4 is introduced through the introduction pipe 11, and a supercharging pressure in the intake passage 2 downstream of the compressor through the introduction pipe 10b. Pressure chamber 7 into which the pressure is introduced
c are formed with the diaphragm 7b interposed therebetween. The displacement of the second push rod 7d interlocking with the diaphragm 7b changes as shown in FIG. 3 due to the pressure difference between the pressure in the exhaust pressure chamber 7a and the pressure in the boost pressure chamber 7c.

The first push rod 6d of the first actuator 6 and the second push rod 7 of the second actuator 7
d is restricted from moving in directions other than the vertical direction in FIG. 1 by the guides 6e and 7e, respectively.

The first push rod 6d and the second push rod 7d are rotatably supported at both ends of the link 8, respectively. The lever 5 a of the nozzle vane 5 is linked with the link 8 via the third push rod 9.

FIG. 4 shows a turbocharger according to this embodiment. The first actuator 6 and the second actuator 7 are fixed by a bracket 14 supported by a compressor 12. 13 is a center housing.

The operation of this embodiment will be described below with reference to FIG. Supercharging pressure P ₀ or less, and, in the differential pressure between the exhaust pressure and the boost pressure P ₁ or lower load conditions (below the load), the nozzle vanes 5 are fully closed.

When the pressure difference between the exhaust pressure and the supercharging pressure reaches P ₁ , the second push rod 7 d of the second actuator 7 is displaced according to the pressure difference, and is displaced via the link 8 and the third push rod 9. Therefore, since the nozzle vane 5 is opened, the rise in the differential pressure can be suppressed to a minimum (range of-). For this reason, fuel consumption deterioration due to an increase in pumping loss can be suppressed.

When the load increases and the supercharging pressure reaches P ₀ ,
Since the first push rod 6d of the first actuator 6 is displaced and the opening degree of the nozzle vane 5 is increased, an increase in the supercharging pressure can be suppressed, and damage to the engine due to an increase in the in-cylinder pressure can be prevented (above load).

When the nozzle opening is controlled only by the supercharging pressure, the operation is repeated until the supercharging pressure reaches a predetermined value (P ₀ ) (
Since the nozzle remains fully closed, the exhaust pressure greatly exceeds the supercharging pressure, and the fuel consumption rate deteriorates (range).

[0019]

As described above, according to the present invention, the nozzle vane 5 for varying the exhaust passage area at the turbine inlet of the turbocharger and the supercharging pressure chamber 6a for introducing the supercharging pressure are formed. A diaphragm-type first actuator 6 driven by a pressure difference between the supercharging pressure and the atmospheric pressure, an exhaust pressure chamber 7a into which the exhaust pressure at the turbine inlet is introduced, and a supercharging pressure chamber 7c into which the supercharging pressure is introduced Are formed, a diaphragm-type second actuator 7 driven by a differential pressure between the exhaust pressure and the supercharging pressure, a first push rod 6d interlocked with the first actuator 6, and interlocked with the second actuator 7 The second push rod 7d is provided with a link 8 supported at both ends, and the link 8 and the nozzle vane 5 are interlocked via a third push rod 9. And without additional control logic, it is possible to suppress deterioration of the fuel consumption rate due to an excessive increase in the exhaust pressure at part load.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is an operation characteristic diagram of a first actuator 6.

FIG. 3 is an operation characteristic diagram of a second actuator 7;

4A and 4B are configuration diagrams of a turbocharger according to an embodiment of the present invention, wherein FIG. 4A is a front sectional view and FIG. 4B is a side view.

FIG. 5 is a diagram showing control of a nozzle opening degree and its effect according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Internal combustion engine main body 2 Intake passage 3 Exhaust passage 4 Turbine 5 Nozzle vane 5a Lever 6 First actuator 6a, 7c Supercharging pressure chamber 6b, 7b Diaphragm 6c Atmospheric pressure chamber 6d First push rod 6e, 7e Guide 7 Second actuator 7a Discharge Atmospheric chamber 7d Second push rod 8 Link 9 Third push rod 10, 10a, 10b, 11 Introducing pipe 12 Compressor 13 Center housing 14 Bracket

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[Procedure amendment]

[Submission date] August 26, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Fig. 4

[Correction method] Change

[Correction contents]

FIG. 4 is a front sectional view and a side view of the turbocharger according to the embodiment of the present invention.

Claims (2)

[Claims] 1. A turbocharged internal combustion engine, comprising: a nozzle vane that varies an exhaust passage area at a turbine inlet of a turbocharger; and a supercharging pressure control unit that increases the nozzle vane opening according to an increase in supercharging pressure. An exhaust pressure control device for an internal combustion engine, comprising: exhaust pressure control means for increasing the nozzle vane opening in accordance with an increase in a differential pressure between an exhaust pressure at a turbine inlet and a supercharging pressure. 2. A turbocharged internal combustion engine, comprising: a nozzle vane that varies an exhaust passage area at a turbine inlet of a turbocharger; and a supercharging pressure chamber into which a supercharging pressure is introduced. A first actuator driven by the differential pressure of the turbine, an exhaust pressure chamber into which the exhaust pressure at the turbine inlet is introduced, and a supercharging pressure chamber into which the supercharging pressure is introduced. A second actuator driven by a pressure difference between the first and second actuators; and a link in which both ends of a first push rod interlocked with the first actuator and a second push rod interlocked with the second actuator are supported. 2. The supercharging pressure control device for an internal combustion engine according to claim 1, wherein the nozzle vane and the nozzle vane are interlocked via a third push rod.