JPS633379Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a wastegate of a supercharger attached to an automobile engine.

BACKGROUND OF THE INVENTION Certain types of automobiles are equipped with turbochargers to increase engine output. As a result, when the engine rotates at high speed, the boost increases and the supercharger also rotates at high speed, increasing engine output. However, at low speeds, this supercharger acts as resistance, causing a slight drop in output. A decrease in output when the engine rotates at low speed is not desirable in actual driving. Therefore, it is common practice to use a small supercharger that operates at maximum efficiency when the engine rotates at medium to low speeds, even if it sacrifices some output increase effect, thereby improving the output drop at low speeds. . However, this will cause the supercharger to overrun when the engine rotates at high speeds, so to prevent this, a wastegate is provided in the exhaust system to allow part of the exhaust gas to escape when the engine is running at high speeds.

FIG. 1 shows an example of such a supercharger with a wastegate. Compressor 1
A conduit 3 is provided in a part of the intake pipe 2 leading from the intake manifold to the boost chamber 5 of the wastegate 4 . The housing 6 of the waste gate 4 has a diaphragm 7
The boost chamber 5 is separated from the atmospheric pressure chamber 8 which is open to the atmosphere. The diaphragm 7 is normally pressed toward the boost chamber 5 by a valve spring 9 provided in the atmospheric pressure chamber 8, and as a result, the waste gate valve 10 whose stem tip is attached to the diaphragm 7
However, a bypass 13 provided in the exhaust pipe 12 is closed so as to bypass the turbine 11. When the engine 14 rotates at high speed and the intake boost increases, this boost causes the diaphragm 7 to
is pressed toward the atmospheric pressure chamber 8 to open the waste gate valve 10, allowing a portion of the exhaust gas to escape to the outside air through the bypass 13.

The opening pressure of the valve 10 in the waste gate 4 is determined by the pressing force of the valve spring 9 that presses the valve 10. However, cars are sometimes exported and used at high altitudes around 3,000 meters above sea level. In this case, if the pressing force of the valve spring 9 remains constant even though the atmospheric pressure has decreased, the valve opening pressure will become relatively high, and the valve 1, which would have been open due to a certain boost on flat ground, will become relatively high.
0 no longer opens at high altitudes, waste gate 4
will no longer perform its function and the supercharger will overrun.

The object of this invention is therefore to provide a wastegate for a supercharger that prevents functional deterioration when used at high altitudes.

An embodiment of this invention will be described below with reference to FIG. Components having similar functions to those shown in FIG. 1 are given the same reference numerals. The inside of the housing 6 of the waste gate 4 is separated by a diaphragm 7 into a lower boost chamber 5 and an upper atmospheric pressure chamber 8. The tip of a stem 10a of a waste gate valve 10 is fixed to the center of the diaphragm 7 downward with a nut 15. Inside the atmospheric pressure chamber 8, a movable disc 16 is provided with bellows 17, 18 sealed with a constant negative pressure or positive pressure.
It is supported flat by. bellows 17,
If positive pressure is sealed in 18, it is necessary to provide a cancel spring 19 between disk 16 and the ceiling of housing 6 to offset this pressure. If negative pressure is sealed in the bellows 17, 18, this cancel spring 1
9 is unnecessary.

The wastegate valve 10 normally closes the exhaust bypass 13 due to the differential pressure between the pressing force of the valve spring 9 and the pressure within the bellows 17 and 18. When driving on flat ground, the diaphragm 7 is pushed up by the intake boost introduced from the conduit 3 into the boost chamber 5, and the valve 10 opens the bypass 13. When driving at high altitudes, the bellows 17 and 18 close due to the drop in atmospheric pressure.
The gas inside expands and pushes up the disk 16, so
The pressing force of the valve spring 9 is weakened, and the valve 10 opens with a smaller boost than when driving on flat ground. In other words, so that the pressing force of the spring 9 weakens as the atmospheric pressure decreases, that is, so that the pressure ratio with the boost always remains constant.
Spring constant of spring 9 and bellows 17,1
Determine the pressure, etc. within 8.

In another embodiment of this invention shown in FIG. 3, a cam surface of an eccentric cam 22 which is swingable around a pin 21 is attached to the top of the valve spring 9 on the diaphragm 7 via a small disk 20. are in contact with each other. A bellows 2 is provided on the side wall of the housing 6 and is sealed with a certain pressure on the top end surface of the eccentric cam 22.
The tip of the actuating piece 23a of No. 3 is pivotally attached to the housing 6, and on the opposite side, a tension coil spring 24 for canceling positive pressure sealing is attached to the housing 6.
installed between the side wall. Similarly, in this embodiment, as the atmospheric pressure decreases, the bellows 23
, the cam 22 is rotated counterclockwise to weaken the pressing force of the spring 9.

As mentioned above, the wastegate of the turbocharger according to this invention changes the opening pressure of the wastegate valve in accordance with fluctuations in atmospheric pressure, so even when used at high altitudes where atmospheric pressure is low, the can prevent overruns.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing an example of a supercharger with a waste gate, Fig. 2 is a schematic diagram of a waste gate showing one embodiment of this invention, and Fig. 3 is a schematic diagram showing another embodiment of this invention. FIG. 2 is a schematic diagram showing only the main parts. 4...waste gate, 5...boost room,
6...Housing, 7...Diaphragm, 8...
Atmospheric pressure chamber, 9... Valve spring, 10... Waste gate valve, 16... Disc, 17, 1
8...Bellows, 19...Cancel spring.

Claims (1)

[Scope of Claim for Utility Model Registration] A wastegate of a supercharger that is activated by intake boost to release part of the exhaust gas when the supercharger rotates at high speed, and is provided in the housing and is used as a boost chamber. a diaphragm for isolation from the atmospheric pressure chamber; a waste gate valve whose stem tip is attached to the diaphragm; and a movable circle supported by a bellows installed in the atmospheric pressure chamber and sealed at a constant pressure state. a plate, and a valve spring compressed between the movable disc and the diaphragm, and when used at high altitudes lower than atmospheric pressure, the pressing force of the valve spring is reduced by extensional deformation of the bellows. A wastegate for a supercharger characterized by being configured as follows.