JPS6245057Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a turbocharger, and particularly to an improvement in a supercharging pressure outlet provided in a scroll portion of a compressor.

Improving the performance of internal combustion engines, that is, increasing output,
A turbocharger that uses exhaust gas is used to reduce size and weight and improve fuel efficiency.
The exhaust gas rotates the turbine wheel of the turbocharger disposed in the exhaust passage of the engine at high speed, and the compressor wheel, which is fixed coaxially with the turbine wheel and disposed within the intake passage, is rotated at high speed to generate intake air. Forming a branch exhaust passage in the engine exhaust passage that bypasses the turbine wheel while supercharging the engine,
A wastegate valve is provided in the branch exhaust passage, and when the supercharging pressure exceeds a set limit value, the wastegate valve is opened to lower the rotational speed of the turbine wheel and suppress an increase in supercharging pressure due to the compressor wheel. It is equipped with a boost pressure control device for the turbocharger.

Boost pressure control is performed by directing the boost pressure of the turbocharger, that is, the pressure on the downstream side of the compressor, to the boost pressure chamber of the actuator connected to the wastegate valve through a communication passage, thereby controlling the high boost pressure that exceeds the limit set value. This is done by occasionally opening the wastegate valve to suppress the increase in the rotational speed of the turbine wheel, thereby preventing engine knocking caused by an increase in supercharging pressure and improving fuel efficiency. It is preferable to take out such boost pressure from the scroll part of the compressor in order to improve control accuracy.
Therefore, a supercharging pressure control device has been proposed in which one end of the communication path to the actuator is opened on the wall surface of the scroll portion (Japanese Patent Application Laid-Open No. 1983-1999-1).
124629).

On the other hand, in internal combustion engines, the so-called blow-by gas that leaks into the crankcase from between the piston and the cylinder wall contains a large amount of hydrocarbons (HC), so this gas is returned to the intake system using intake negative pressure and released into the cylinder. The device for this purpose is known as a blow-by gas reduction device.

When this blowby gas reduction device is attached to the above-mentioned turbocharged internal combustion engine, the blowby gas is sent to the suction side of the compressor through the air cleaner, but at this time, the oil mist contained in the blowby gas is not completely removed. When taken into the compressor, the blow-by gas is heavier than air, so it is affected by the centrifugal force of the rotation of the compressor wheel and scattered on the outer wall of the scroll section. As a result, oil mist adheres to the boost pressure outlet of the scroll section. Otherwise, the oil mist may be taken into the boost pressure introduction passage and enter the actuator or other control valves, adhere to each moving part, such as the valve body, and reduce its viscosity. This may cause problems such as interfering with their operation.

The present invention has been made in view of the above points, and provides a turbocharger having a compressor wheel disposed coaxially with a turbine wheel rotated by exhaust gas of an internal combustion engine and supplying pressurized air to the engine. By protruding the provided boost pressure outlet opening end to the inside of the scroll portion, it is possible to prevent oil mist, etc. from entering from the scroll portion into the boost pressure chamber of the actuator or the control valve, etc. The purpose is to provide a turbocharger.

An embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

In FIG. 1, a turbine wheel 1a of a turbocharger 1 is arranged in an exhaust passage 3 of an engine 2, and a compressor wheel 1b fixed to a rotating shaft 1c of this turbine 1a is arranged in an intake passage 4. A branch exhaust passage 5 that bypasses the turbine wheel 1a is formed in the exhaust passage 3,
A waste gate valve 6 is disposed in the passage 5.

The actuator 7 is divided into two chambers 7a and 7b by a diaphragm 8, one of which is the chamber 7a.
A hole 7c for venting to the atmosphere is bored approximately in the center of the side end face, forming an atmospheric pressure chamber. One end of the rod 9 loosely passes through the hole 7c and is fixed approximately in the middle of the diaphragm 8 within the atmospheric pressure chamber 7a, and the other end is rotatably supported at a predetermined position on the rod 10. Rod 1
One end of the rod 0 is rotatably supported by a pin 11, and the other end is connected to the waste gate valve 6, and a link mechanism 12 is constituted by these rods 9, 10, pin 11, etc. The coil spring 13 is disposed in the atmospheric pressure chamber 7a, and has one end pressed against the diaphragm 8 and the other end pressed against the end face 7d facing the diaphragm 8, and a rod 9 freely passes through its axis. This spring 13 is used to determine the limit set value of the supercharging pressure, and acts to press the diaphragm 8 rightward in the figure with a predetermined spring pressure to close the wastegate valve 6.

The other chamber 7b of the actuator 7 is a boost pressure chamber, and communicates with the scroll portion 1d of the compressor 1b of the intake passage 4 via a passage 14. Further, a throttle 14a is provided at a predetermined location of the passage 14, and a control valve, such as a solenoid valve 15, is provided in communication with the downstream side of the throttle 14a. The solenoid valve 15 is a normally closed valve, and the atmosphere communication port 15a is opened to the atmosphere via the air cleaner 16. Inside the casing 15c, there is a valve body 15b and a solenoid 1 which are disposed so as to be able to open and close the communication port 15a.
5d is provided. and solenoid 15
d is an electronic control unit (not shown) (hereinafter referred to as
(referred to as ECU), and the solenoid valve 15 is controlled to open and close by the ECU. In addition, code 17
1 is an air cleaner for the intake passage 4, and reference numeral 18 is an intercooler disposed in the intake passage 4 in order to lower the temperature of the pressurized intake air and increase the output of the engine.

An open end 14b of the passage 14 to the compressor scroll portion 1d is connected to an open end 19b of the adapter 19, as shown in FIG. This adapter 19 is inserted into and fixed to a boss portion 1e formed on the outer wall surface of the scroll portion 1d in the direction of the shaft 1c, for example, and its tip portion 19a is attached to the scroll portion 1d.
d protrudes a predetermined length inside to form a supercharging pressure outlet. Further, FIG. 3 shows a schematic side view of the compressor section, and the adapter 19 is arranged at the lower part of the scroll section 1d provided in a spiral shape between the air intake port 1f and the air outlet 1g.

Now, when the turbine wheel 1a rotates at high speed due to the exhaust gas from the engine 2, the compressor wheel 1b also rotates at high speed and the air cleaner 1
The air taken in through the pump 7 is pressurized to generate supercharging pressure. Then, the air whose flow rate corresponds to this supercharging pressure is cooled by the intercooler 18, and the air is cooled by the intercooler 18.
Inside, the fuel is mixed with fuel injected from a fuel injector (not shown) and then supplied to the combustion chamber of the engine 2.

As the engine speed increases, the exhaust gas pressure increases and the rotation speed of the turbine wheel 1a increases, so the boost pressure generated by the compressor wheel 1b also increases, and the boost pressure is set at the limit value. 1, the pressure of the scroll portion 1d of the compressor wheel 1b moves the diaphragm 8 to the left in FIG. Open the exhaust passage 5. As a result, part of the exhaust gas in the exhaust passage 3 bypasses the turbine wheel 1a through the branched exhaust passage 5, and the rotational speed of the turbine wheel 1a, that is, the rotational speed of the compressor wheel 1b, decreases accordingly. As a result, the boost pressure is prevented from increasing beyond the set limit value.
On the other hand, in addition to this, the solenoid valve 15 is controlled to open and close at a predetermined duty ratio by a control signal from the ECU, and as a result, the boost pressure chamber 7 of the actuator 7
b pressure is controlled.

During such operation, as shown in FIG. 2, air taken in from the air intake port 1f by the compressor wheel 1b flows in a spiral shape as shown by the arrow inside the scroll portion 1d, and is compressed into the air outlet. 1g (Fig. 3) and is discharged into the intake passage 4 (Fig. 1). As the air flow inside the scroll portion 1d is spiral as described above, oil mist, etc. in the blow-by gas, which is heavier than air, is scattered on the inner wall surface of the scroll portion 1 d due to centrifugal force, and the oil in the blow-by gas is Mist adheres to the wall surface.
However, in the present invention, the air passage 14
Since the tip 19a of the adapter 19 connected to the scroll part 1d protrudes into the inside of the scroll part 1d, it is difficult to inhale oil mist near the inner wall surface, and always supplies clean air to the boost pressure chamber 7b of the actuator 7 and the solenoid valve. In particular, oil mist does not adhere to the valve body 15b of the solenoid valve 15 and obstruct the opening/closing operation of the valve body 15b.

As explained above, in the present invention, in a turbocharger having a compressor wheel disposed coaxially with a turbine wheel rotated by exhaust gas of an internal combustion engine and supplying pressurized air to the engine, the compressor wheel is installed in the scroll portion of the compressor. Since the opening end of the boost pressure outlet is made to protrude inside the scroll part, even if the blow-by gas sent to the suction side of the compressor contains oil mist, no oil mist will be present at the boost pressure outlet. Since the supercharging pressure chamber of the actuator and other control devices can always be supplied with clean supercharging pressure, the control accuracy of the supercharging pressure is improved.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram showing the entire supercharging pressure control device for a turbocharger including a turbocharger according to the present invention, and Fig. 2 is an enlarged sectional view of main parts showing the structure of the supercharging pressure outlet of the compressor scroll part. ,
FIG. 3 is an end view seen from the arrow direction of FIG. 2. 1...Turbo charger, 1a...Turbine wheel, 1b...Compressor wheel, 1d...
...scroll section, 7...actuator, 14...
...Aisle, 19...adapter.

Claims (1)

[Scope of utility model registration request] In a turbocharger having a compressor wheel disposed coaxially with a turbine wheel rotated by exhaust gas of an internal combustion engine and supplying pressurized air to the engine, an opening end of a supercharging pressure outlet provided in a scroll portion of the compressor. 1. A turbocharger characterized in that a turbocharger is made to protrude into the inside of the scroll portion.