JPS6135706Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an exhaust gas switching device for a turbocharger.

In a turbocharged engine, the turbine efficiency can be improved by exposing the turbine scroll to high-speed gas immediately after the valve is opened.

In addition, in multi-cylinder engines, in order to prevent the exhaust gases that come out at different timings from interfering with each other, causing a relative drop in exhaust pressure and reducing turbine efficiency, the exhaust path leading to the turbine is Sometimes it is divided into two paths to avoid exhaust interference.

On the other hand, when the engine speed is low, the flow rate of exhaust gas decreases and the turbine efficiency decreases. This system aims to prevent a decrease in turbine efficiency by guiding the exhaust gas only to increase the flow velocity.

For example, in Utility Model Application No. 50-8306, which was immediately disclosed, as shown in FIG. 1, a heavy load nozzle 1a and a light load nozzle 1b corresponding to the turbine chamber inlet
A switching valve 2 is provided to selectively open and close each of these two nozzles, and a signal from a pressure switch 4 provided in the exhaust path 3 is used to switch the heavy load nozzle 1a when the gas pressure in the exhaust path 3 is high. In addition, when the gas pressure is low, the nozzle 1b for light load is switched to the nozzle 1b for light load.

Or, in Utility Model Application No. 52-46105, the second
As shown in the figure, swingable variable blades 6 are attached to appropriate positions of a partition wall 5 provided to form a plurality of entries (exhaust gas passages) between the turbine nozzle part and the exhaust manifold. By operating the variable vane, exhaust gas flowing through some of the plurality of entries is made to merge with exhaust gas flowing through other entries.

In both of these, a part of the partition wall 5 is provided as the pivot point A of the switching valve 2 and the variable blade 6, and the switching valve 2 rotates.
It is configured such that one exhaust path is blocked by the edge of the variable blade 6.

However, providing such a pivot point A on a part of the partition wall 5 requires a complicated structure, and it is extremely difficult to process this along with the contact portion of the exhaust path 3 with the switching valve 2 and the edge of the movable blade 6. Moreover, it is difficult to obtain good exhaust gas sealing properties, and there is a problem that it is impractical.

The present invention is intended to solve the above-mentioned problems, and aims to provide an exhaust gas switching device for a turbocharger that has a simple structure and good exhaust gas sealing properties.

Examples will be described below with reference to the drawings.

As shown in FIG. 3, this switching device 7 is interposed between the inlet of the turbine housing 8 of the turbocharger and the outlet of the exhaust manifold 9, and its details are shown in FIGS. 4 and 5. It will be done.

The main body housing 10 is a rectangular parallelepiped, and has a passage 11 communicating with the outlet passage of the exhaust manifold 9, and a branch that is partitioned by a partition wall 5 and each communicates with a partitioned inlet (not shown) of the turbine housing 8. Channels 12, 13 are formed.

A part of one of the branch passages 12 is formed in a circular hole 14, and a butterfly valve 15 that is in close contact with the inner periphery of the circular hole 14 when fully closed is rotatably supported by the main body housing 10 via a shaft 16. The branch passage 12 is opened and closed by actuation by a control means such as an air cylinder (not shown).

Inside the main body housing 10 is a shaft 16.
A water jacket 18 is formed to surround the boss portion 17 supporting the branch passages 12 and 13, and an inlet 19, an outlet 2
The cooling water of the engine cooling system flows back through the inlet pipe 23 and outlet pipe 24 connected to the engine as shown by the arrow.

In the above configuration, when the engine is running at high speed, the butterfly valve 15 is fully opened in parallel to the center line of the device, as shown by the two-dot chain line, by a control means such as an air cylinder.

As a result, the exhaust gas passes through the branch paths 12 and 13, thereby avoiding exhaust interference and improving turbine efficiency.

Next, when the engine is running at low speed, the butterfly valve 15 is rotated in the direction of the arrow by a control means such as an air cylinder and closes the branch passage 12 by coming into close contact with the inner periphery of the circular hole of the branch passage 12, as shown in the figure. do.

As a result, the exhaust gas is guided to only one branch path 13 and throttled, so the flow velocity increases and a decrease in turbine efficiency is therefore prevented.

This butterfly valve 15 is disc-shaped like the one for the exhaust brake, and is in close contact with the inner periphery of the circular hole 14 of the branch passage 12, so that it can reliably shut off exhaust gas. As a result, the speed increasing effect of the exhaust gas passing through the branch path 13 is improved.

In addition, the shaft 16 of the butterfly valve 15
is the water jacket 1 around the boss part 17.
8, the stagnation due to exhaust heat is reliably prevented.

On the other hand, since the circular hole portion 14 of the branch passage 12 is perfectly circular, it can be processed using a normal machine tool, so it is extremely easy to process it together with the disc-shaped butterfly valve 15, and high precision can be achieved. As a result, high sealing performance between the two can be obtained.

As described above, the present invention forms two perfectly circular branch passages in parallel in the main body housing interposed between the exhaust manifold and the turbine housing, and a circular plate is placed at the entrance of one of the branch passages. A water jacket is formed in the main body housing at the supporting part of the butterfly valve shaft and around the butterfly valve in the closed state, and a part of the engine cooling water is supplied to the water jacket. Since the butterfly valve is configured to circulate, it provides a good seal when the butterfly valve is closed, increasing the flow rate of exhaust gas and improving turbine efficiency.At the same time, the area around the butterfly valve and the valve shaft is cooled by cooling water. Therefore, even if the butterfly valve is exposed to the heat of high-temperature exhaust gas, it is possible to reliably prevent valve sticking, and it is also possible to improve the heat resistance of the butterfly valve.

[Brief explanation of the drawing]

FIGS. 1 and 2 are cross-sectional views showing a conventional device;
FIG. 3 is a side view showing an embodiment of the present invention, FIG. 4 is a detailed sectional view of the main body housing of FIG. 3, and FIG. 5 is a sectional view taken along the - line in FIG. 4. 1...Switching valve, 3...Exhaust path, 5...Bulkhead, 6
...Variable blade, 8...Turbine housing, 9...
Exhaust manifold, 10...Body housing, 11...Passway, 12, 13...Branch passage, 14
...Round hole part, 15...Butterfly valve, 16...
...Shaft, 17...Boss section, 18...Water jacket.

Claims (1)

[Scope of utility model registration request] Two perfectly circular branch passages are formed in parallel in the main body housing interposed between the exhaust manifold and the turbine housing, and a disc-shaped butterfly valve is provided at the entrance of one of the branch passages. a water jacket is formed in the main body housing at a support portion of the butterfly valve shaft and around the butterfly valve in a closed state;
An exhaust gas switching device for a turbocharger, characterized in that it is configured to circulate a portion of engine cooling water through the water jacket.