JPS6367012B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device that adjusts the boost pressure based on the flow rate adjustment of the exhaust flow flowing into the turbine of a supercharger. The present invention relates to a boost pressure control device for controlling

BACKGROUND ART Conventionally, a supercharger has been used that uses exhaust energy from an engine to increase air supply pressure to increase engine output. In this supercharger, it is necessary to regulate the flow rate of exhaust gas flowing into the turbine side so that the compressor does not perform excessive supercharging in an emergency such as overrun or overheating of the exhaust system. For this reason, the supercharger is equipped with a bypass passage that is opened and closed by the wastegate valve so that a portion of the exhaust gas bypasses the turbine and is discharged directly to the atmosphere. By the way, many waste gate valves are equipped with a diaphragm that operates using supercharging pressure as an actuator that opens and closes the valve body. For example, “Separate Volume Automotive Engineering Car Technology No. 6, Publisher:
Connect the waste gate valve to the diaphragm via a link, as disclosed in the Japanese Railway Company,
This diaphragm is operated with boost pressure. In this case, when the boost pressure exceeds the set value, the diaphragm resists the return spring and opens the wastegate valve, so part of the exhaust gas flows from the bypass path to the exhaust pipe side, causing the turbine rotation and boost pressure to exceed the set value. can be prevented from climbing. However, this diaphragm type actuator regulates the turbine rotation and boost pressure only by the characteristics of the attached return spring, and cannot control the boost pressure more appropriately depending on the mode of the engine.

An object of the present invention is to provide a boost pressure control device that can control boost pressure more appropriately.

The boost pressure control device according to the present invention includes a flow control valve that detours a part of the exhaust gas toward the turbine of the supercharger to the bypass path side, and controls the boost pressure by adjusting the opening/closing amount of the flow control valve. In the device for controlling the flow rate, the pressure adjusting means introduces the boost pressure, adjusts the boost pressure according to the operating conditions of the engine, and derives the adjusted pressure; a first diaphragm that drives the control valve to open and close; and a first diaphragm that is disposed as a separate body so as to be movable relative to the first diaphragm and that is configured to be able to press the first diaphragm in the opening direction of the flow rate control valve. 2 diaphragm, and a first diaphragm that biases the flow control valve in the valve closing direction via the first diaphragm.
Adjustment pressure is introduced from the pressure adjustment means formed between the spring, the first diaphragm, and the second diaphragm, and presses the first diaphragm against the biasing force of the first spring to open the flow rate control valve. A first pressure chamber that is driven to open the valve, and a second pressure chamber that is driven to open the valve.
a second spring that comes into contact with the diaphragm and biases the second diaphragm in a direction away from the first diaphragm; and a second spring that is separated from the first pressure chamber by the second diaphragm and receives the supercharging pressure. The present invention is characterized by comprising an actuator having a second pressure chamber that applies a pressing force to the first diaphragm via the second diaphragm based on the differential pressure between the supercharging pressure and the adjustment pressure in the first pressure chamber.

The present invention will be described below with reference to the accompanying drawings.

The drawing shows an engine 1 equipped with a boost pressure control device as an embodiment of the present invention. This engine measures the flow rate of fresh air taken in from an air cleaner 2 with an air flow meter 3, pressurizes it with a compressor 5 of a supercharger 4, and transfers the pressurized fresh air to an intercooler 6.
After passing through, it is supplied to cylinder 7. Then, the exhaust gas from the cylinder 7 is guided to the turbine 8 of the supercharger 4, and the exhaust gas after passing through the turbine is passed through the catalytic converter 9 and the muffler 10 and released into the atmosphere. The output signal of the air flow meter 3 is input to a microcomputer (hereinafter simply referred to as "microcomputer") 11,
This microcomputer outputs an amount of fuel corresponding to the output signal so that a fuel injection device (not shown) injects it. An exhaust path E extending from the cylinder 7 of the engine branches into an inlet 801 side of the turbine 8 and a bypass path B side. The exhaust gas flowing into the inlet 801 uses its kinetic energy to rotate the turbine 8 and flows out to the exhaust pipe 13 side. The bypass path B can merge with the exhaust path E of the exhaust gas after passing through the turbine 8 via the waste gate valve 14 as a flow rate regulating valve. The waste gate valve 14 has its lower end connected to the pin 1 on the base side.
5, and the valve portion 141 on the upper end side closes the bypass path B by being rotationally biased clockwise. One end of the connecting rod 16 is locked midway between the valve portion and the pin 15 mounting position. The other end of this connecting rod is connected to a first diaphragm 18 in an actuator 17 supported by a base (not shown).

The actuator 17 has a bottomed cylindrical outer frame 12 that is long in the longitudinal direction of the connecting rod 16, and inside the outer frame are the first diaphragm 18, the first pressure chamber 19, the second diaphragm 20, and the second diaphragm 20. 2 pressure chamber 2
1 are deployed in this order. First diaphragm 1
8 is subjected to an elastic pressing force in the valve closing direction C by the first spring 22 whose one end is brought into contact with the annular end 901 of the outer frame 12 . The first diaphragm has a spring receiving member 23, which is open at the center and fixed to the outer frame 9 at the outer periphery, close to the side surface of the first pressure chamber 19. A second spring 24 is installed between this spring receiving member and the second diaphragm 20, and this spring causes the second diaphragm 20 to
is always subjected to an elastic force in the valve closing direction C. The first pressure chamber 19 includes a pair of diaphragms 18 and 20 and an outer frame 12.
The inside of the chamber is connected via a pipe 32 to a solenoid valve 25 as a pressure regulating valve. on the other hand,
The second pressure chamber 21 includes an outer frame 12 and a second diaphragm 2.
0, and the interior of the room communicates with the outlet 501 of the compressor 5 via a pipe 26. The solenoid valve 25 has a pressure chamber port a on the first pressure chamber 19 side,
It is equipped with a supercharging pressure port b on the pipe 26 side and an atmospheric port c that is opened to the atmosphere, of which the supercharging pressure port b and the atmospheric port c are arranged opposite to each other,
When one of the two is closed by the valve body 251, the other is opened. A throttle 28 is attached to the pipe 27 that connects the pipe 26 to the boost pressure port b, a throttle 29 is attached to the pipe 32, and a throttle 31 is attached to the pipe 30 extending from the atmospheric port c. solenoid valve 2
The pressure value controlled by No. 5 is adjusted. The valve body 251 is disposed opposite to an excitation coil 252, and is activated when this coil receives an output signal from the microcomputer 11. That is, the microcomputer 11 outputs to the solenoid valve 25 an output signal whose duty ratio is varied in magnitude. As a result, the pressure value of the first negative pressure chamber 19 increases in proportion to the increase in the duty ratio, and the first diaphragm 18 maintains the opening degree of the waste gate valve 14 at a predetermined value in accordance with this pressure value.

The microcomputer 11 is connected to an engine rotation sensor 33 for detecting the engine rotation speed, an exhaust path high temperature sensor 34, a knock sensor 35, etc., and each output signal is inputted from these.

The operation of such a supercharger control device will be explained.
When the engine starts, the turbine 8 is driven by exhaust gas, the compressor 5 pressurizes fresh air, and the supercharger 4 works to cause the engine 1 to generate a predetermined output. At the same time, actuator 17 and microcomputer 11
also works.

The second pressure chamber 21 of the actuator constantly receives supercharging pressure P1 and pushes the second diaphragm 20 in the valve opening direction O against the pressing force of the second spring 24. The first pressure chamber 19 has a regulated pressure P regulated by a solenoid valve 25 that operates in response to an output signal from the microcomputer 11.
2 (P2<P1) acts, which presses the first diaphragm 18 in the valve opening direction O against the pressing force of the first spring 22, and also presses the second diaphragm 20 in the valve closing direction C. The second diaphragm 20 is separated from the first diaphragm 18 by the resultant force of the pressing force based on this pressure P2 and the elastic force of the second spring 24. In this case, unless there is a set emergency, the output level of the microcomputer 11 increases or decreases in a predetermined range according to the engine speed, and the waste gate valve 14 is rotated by a predetermined amount only by the adjusted pressure P2 of the first pressure chamber 19. do. As a result, the turbine rotation speed increases or decreases within the set value. On the other hand, in an emergency, for example, when a knock occurs, the microcomputer 1
1 emits a high level output. Then, the solenoid valve provides the first pressure chamber 19 with an adjusted pressure P2 close to the supercharging pressure P1. At this time, the second diaphragm 20 receives supercharging pressure on both sides and mainly receives the elastic force of the second spring 24, so that it is separated from the first diaphragm 18 side. At the same time, waste gate valve 1
4 is fully opened by the first diaphragm 18, the turbine rotational speed is suppressed within a set value, and damage to the supercharger 4 and engine 1 is prevented.

Furthermore, if the microcomputer 11 or the solenoid valve 25 breaks down, first, if the valve body 251 closes the atmospheric port c and opens the boost pressure port b, the first
Diaphragm 18 opens wastegate valve 14 in response to boost pressure P1. Conversely, when the valve body 251 opens the atmospheric port c and closes the supercharging pressure port b, the first pressure chamber 19 becomes atmospheric pressure, the second pressure chamber 21 receives the supercharging pressure P2, and the first pressure chamber 19 becomes atmospheric pressure. The second diaphragm 20 presses the first diaphragm 18 in the valve opening direction O, and opens the wastegate valve 14 in accordance with the boost pressure. That is, if the microcomputer 11 or the solenoid valve 25 fails, the wastegate valve 14 will open by the amount corresponding to the supercharging pressure regardless of the state in which the valve body 251 is fixed.

In this way, the boost pressure control device controls the adjustment pressure P2, which is regulated by the solenoid valve, which is applied to the first pressure chamber 19 while the engine 1 is operating in a normal state, and the first pressure chamber, which has a relatively small spring constant. The waste gate valve 14 can be opened and closed by the balanced operation with the spring 22. On the other hand, in an emergency, the waste gate valve 14 is opened wide with the adjusted pressure P2 close to the supercharging pressure to prevent damage to the engine 1 and the supercharger 4. Moreover, even when the microcomputer 11 or the solenoid valve 25 breaks down, the waste gate valve 14 is opened wide. The waste gate valve 14 can be opened according to the pressure, and problems that may cause damage to the engine 1 and the supercharger 4 are also prevented.

[Brief explanation of drawings]

The drawing shows a schematic configuration diagram of an engine equipped with a boost pressure control device as an embodiment of the present invention. 4...Supercharger, 8...Turbine, 14...Wastegate valve, 17...Actuator, 18...First
Diaphragm, 19...First pressure chamber, 20...Second diaphragm, 21...Second pressure chamber, 22...First spring, 24...Second spring, 25...Solenoid valve, B...Bypass path, P1...Supercharging pressure.

Claims (1)

[Claims] 1. In a device that is equipped with a flow control valve that detours a part of the exhaust gas toward the turbine of a supercharger to the bypass path side, and that controls supercharging pressure by adjusting the amount of opening and closing of this flow control valve, the supercharging pressure is a pressure regulating means that is introduced and regulates the supercharging pressure according to the operating condition of the engine to derive a regulating pressure; and a first diaphragm that is connected to the flow control valve via a connecting rod and drives the flow control valve to open and close. a second diaphragm that is disposed separately and movable relative to the first diaphragm and is configured to be able to press the first diaphragm in the opening direction of the flow rate control valve; A first spring biases the flow rate control valve in the valve closing direction, and a regulating pressure from the pressure regulating means formed between the first diaphragm and the second diaphragm is introduced, and the biasing force of the first spring is a first pressure chamber that presses the first diaphragm against the pressure to open the flow control valve;
a second spring that biases the diaphragm in a direction away from the first diaphragm; and a second spring that is separated from the first pressure chamber by the second diaphragm and receives the supercharging pressure and is configured to receive the supercharging pressure and the first pressure. A supercharging pressure control device comprising an actuator having a second pressure chamber that applies a pressing force to the first diaphragm via the second diaphragm based on a pressure difference between the chamber and the adjusted pressure.