JPH09268922A - Control device of turbocharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To optimize a valve opening degree even in intermediate speed and an intermediate load range by forming the return spring side of a diaphragm actuator as an air tight chamber, connecting the air tight chamber to a vacuum pump through a three way valve, and controlling the three way valve by engine rotational speed and a load. SOLUTION: At the time of operation of an engine 1 provided with a turbocharger interposed a waste gate valve 10 in a bypass passage 13, the three way valve 15 in a vacuum circuit B is switched by a signal from a control device 19 for inputting output signals of an engine rotational speed sensor 20 and a load sensor 21. Namely, in the case of intermediate and right load, the vacuum circuit B is opened, and the diaphragm 11a of the actuator 11 is controlled by a balance between the negative pressure of a negative pressure chamber 11g and positive pressure of a positive pressure chamber 11h. On the other hand, in the case of high load, the actuator 11 is controlled by only positive pressure in the positive pressure chamber 11h. It is thus possible to generate proper boost pressure by the load direction of the engine 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turbocharger control device for controlling a wastegate of a wastegate type turbocharger by using a diaphragm actuator.

[0002]

2. Description of the Related Art Conventionally, the technique of opening the wastegate valve for controlling the upper limit of the supercharging pressure is to introduce the supercharging pressure on the compressor side to an actuator and control the wastegate valve provided on the turbine side. Are known.

Further, the above technique has a problem that the fuel consumption is deteriorated in the partial load in the high speed range where the valve opens. In order to improve this, use the brake air for the vehicle brake or the brake booster,
Techniques for arbitrarily opening and closing the wastegate valve are also known (for example, Japanese Patent Laid-Open Nos. 2-16331 and 2-3
5713, etc.).

[0004]

However, in the above-mentioned technique, when the boost pressure on the compressor side is used, there are only two points, the valve opening is fully open or fully closed, and the opening is at full load. It is necessary to select the optimum position of. on the other hand,
The valve opening that minimizes fuel consumption at partial load is generally different from the opening at full load.

Further, when the brake air is used, it is necessary to provide a dedicated air circuit for controlling the turbocharger on the vehicle side, resulting in a complicated and troublesome layout and an increase in cost.

Therefore, in view of the above problems, it is an object of the present invention to provide a wastegate valve type turbocharger control device capable of obtaining an optimum valve opening degree even in a medium / high speed / medium load range.

[0007]

According to the present invention, in a turbocharger control device for controlling a wastegate of a wastegate type turbocharger using a diaphragm actuator, a return spring side of the diaphragm actuator is an airtight chamber, The airtight chamber is connected to a vacuum pump via a three-way valve, one of which is open to the atmosphere, and the three-way valve electrically connects to the control device that switches the airtight chamber of the diaphragm actuator between the vacuum side and the atmosphere open side by the engine speed and load. Connected by a circuit.

Further, according to the present invention, it is preferable that the vacuum pump is constructed integrally with the generator.

[0009]

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

FIG. 1 is an overall block diagram showing an embodiment of a control device for a turbocharger according to the present invention. An intake pipe 2 of an engine, which is generally designated by 1, is connected to a compressor section 3 of the turbocharger. A turbine unit 5 of a turbocharger is connected to the exhaust pipe 4. The compressor wheel 3a and the turbine wheel 5a are connected by a shaft 6 via a bearing 7.

Further, a bypass passage 13 is provided so as to join the exhaust passage 14 from the upstream side of the turbine section 5, and a waste gate valve 10 for opening and closing the bypass passage is provided in the bypass passage 13, and the valve 10 is a diaphragm. It is connected to the rod 12 of the actuator 11.

Referring to FIG. 2, the actuator 11 includes a diaphragm 11a provided on a case, a return spring 11b, a spring seat 11c and a seal 1.
A negative pressure chamber 11g that is a hermetically sealed chamber is formed on the side of the return spring 11b with the rod 12 that is airtightly sealed in 1d, and a positive pressure chamber 11h that has a connection hole 11e that is connected to the outlet 3b of the compressor unit 3 And the vacuum hole 11f of the negative pressure chamber 11g connected to the three-way valve 15.

The connecting hole 11e is connected to the outlet 3b of the compressor section 3 by the air circuit A, and the vacuum hole 11f is connected to the generator 17 of the engine 1 via the three-way valve 15.
To the vacuum circuit B. Also, three-way valve 1
The drive unit 15b of No. 5 is connected to the control device 19 by an electric circuit, and the control device 19 is connected to an engine speed sensor 20 and a load sensor 21 (not shown) by an electric circuit. Here, reference numerals 15a and 16a are atmosphere opening holes, 18 is a generator pulley, 18a is a V belt, 8 is an intake valve, 9 is an exhaust valve, 22 is a piston, 23 is a connecting rod, and 24 is a cylinder, respectively. . Further, the vacuum pump is not limited to the one configured integrally with the generator.

Further, the diaphragm actuator 11
The connection hole 11e may be connected to the brake air (not shown) instead of the compressor portion of the turbocharger.

The operation will be described below with reference to FIG. FIG. 3 is a characteristic curve showing the engine load on the horizontal axis and the fuel consumption and boost pressure on the vertical axis, and the boost pressure characteristic and the fuel consumption characteristic respectively correspond to a solid line and a chain line.

In operation, the three-way valve 1 of the vacuum circuit B
5 is switched by a signal from the control device 19,
In the case of a light load, the vacuum circuit is opened (the position shown in the figure) and the diaphragm 11a moves to the negative pressure of the negative pressure chamber 11g and the positive pressure chamber 1.
It is controlled by the balance with the positive pressure of 1h, the vacuum circuit is opened in the case of a high load, and the actuator 11 is controlled only by the positive pressure of the positive pressure chamber 11h which is the pressure of the compressor unit 3. Therefore, the characteristic C becomes an intermediate value between the characteristic D under the control of the known wastegate valve and the characteristic E under the condition that the valve is fully opened when the brake air is used, for example, and an appropriate boost pressure can be obtained depending on the engine load direction.

Further, since the pressure of the compressor portion 3 of the turbocharger is low at the time of low speed rotation, only the operation by vacuum is performed, but the three-way valve 15 is controlled to be closed if necessary.

In the case of the above control, the three-way valve 15 is opened or closed (opened to the atmosphere) and fixed, so that when the three-way valve communicates with the vacuum pump (open), the internal pressure of the negative pressure chamber 11g of the accumulator 11 is increased. Is the same as the vacuum pump,
There is only one type of balance with positive pressure. That is, one characteristic C is fixed.

Therefore, if the three-way valve 15 is controlled to switch between open and close in a very short cycle, the negative pressure can be controlled arbitrarily. The technique of this three-way valve is an application of the technique used for controlling a well-known continuously variable variable capacity turbocharger.

Therefore, as shown in the experimental result of FIG. 3, medium-high speed / medium load (range G) which is frequently used in practice.
Fuel consumption in is improved.

[0021]

EFFECTS OF THE INVENTION Since the present invention is constructed as described above, it is possible to provide an electronically controlled wastegate with a simple structure and at a low cost, and to improve running fuel efficiency in medium-high speed / medium load, which is frequently used in normal running. To be done.

[Brief description of drawings]

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

FIG. 2 is a side sectional view of a diaphragm actuator that is a main part of FIG.

FIG. 3 is a diagram for explaining the function and effect of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Intake pipe 3 ... Compressor part 4 ... Exhaust pipe 5 ... Turbine part 10 ... Waste gate valve 11 ... Diaphragm actuator 15 ... Three-way valve 16. ..Vacuum pumps 19 ... Control devices

Claims (2)

[Claims] 1. A turbocharger control device for controlling a wastegate of a wastegate turbocharger by using a diaphragm actuator, wherein a return spring side of the diaphragm actuator is an airtight chamber, and one of the airtight chambers is open to the atmosphere. It is connected to a vacuum pump via a three-way valve, and the three-way valve is connected by an electric circuit to a control device that switches the airtight chamber of the diaphragm actuator between the vacuum side and the atmosphere release side depending on the engine speed and load. Control unit for turbocharger. 2. The turbocharger control device according to claim 1, wherein the vacuum pump is configured integrally with a generator.