JPH09158741A - Exhaust gas turbosupercharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain supercharging of a high pressure ratio at low cost by composing a compressor of an exhaust gas turbosupercharger of low pressure and high pressure compressors, and providing an intermediate cooler in an air passage between the air outlet of the low pressure compressor and the air inlet of the high pressure compressor. SOLUTION: An exhaust gas radial turbine 3 is fixed to one end of a rotor shaft 1, and a lower pressure stage radial compressor 21 is fixed to the other end of the rotor shaft 1. A high pressure stage radial compressor 22 fixed to the rotor shaft 1 is provided adjacently to the inside of the compressor 21. Both compressors 21, 22 are juxtaposed so that the outlet side is placed back to back, and low pressure and high pressure casings 61, 62 with air passage formed to pass the respective compressors 21, 22 are fixed to each other. An air inlet of an intermediate cooler 11 is connected to an air outlet passage 14 of the low pressure casing 61 through an air pipe 12, and an air outlet is connected to an air inlet passage 15 of the high pressure casing 62 through an air pipe 13 so as to effectively cool supercharged air.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas turbine supercharger used in an internal combustion engine, particularly a large diesel engine.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional example of an exhaust gas turbine supercharger for a large diesel engine.

In FIG. 3, 1 is a rotor shaft, 2 is a radial compressor that compresses air and sends it to an engine, 3 is a radial turbine that is driven by exhaust gas from the engine, and the radial compressor is provided at one end of the rotor shaft. Two
Is arranged at the other end, and the central portion is supported by the bearing housing 8 via two sets of flat bearings 4. Reference numeral 6 is a compressor casing, and 7 is a turbine casing.

An oil labyrinth 5 is provided outside the two sets of plain bearings 4, and the sliding portion between the plain bearing 4 and the rotor shaft 1 is sealed by the air flowing through the compressor 2.

[0005]

DISCLOSURE OF THE INVENTION In a diesel engine using the above exhaust gas turbine supercharger,
When supercharging with a high pressure ratio is required, the performance of a single-stage turbocharger as shown in Fig. 3 is usually improved to perform supercharging with one unit, or a plurality of single-stage superchargers are used. I'm using two (usually two).

However, in the case of the former method, since the rotation speed of the supercharger is increased, the stress of the rotor such as the rotor shaft 1, the compressor 2 and the turbine 3 is increased, and the plain bearing 4 is used. However, there is a problem in that the bearing conditions in (1) become severe and the compressor efficiency further decreases.

In the latter case, the installation space for a plurality of superchargers becomes large, making it difficult to mount the turbocharger on the engine. If the turbocharger is installed separately from the engine, the piping becomes long and complicated. However, there is a problem that cost increase is inevitable.

An object of the present invention is to provide an exhaust gas turbine capable of realizing supercharging at a high pressure ratio at a low cost without lowering the strength of rotating parts, shortening the bearing life, and lowering the efficiency of the supercharger. To provide a supercharger.

[0009]

Means for Solving the Problems The present invention solves the above-mentioned problems, and the gist of the invention is to provide an exhaust gas turbine supercharger in which a turbine and a compressor are fixed to both ends of a rotor shaft. The compressor comprises a low-pressure compressor for pressurizing air from the atmosphere and a high-pressure compressor for further pressurizing the compressed air by the low-pressure compressor, which are fixed to the rotor shaft. The intercooler for cooling the air to the high pressure compressor is provided in the air passage between the air inlet and the air inlet.

According to the above means, the high-pressure compressor and the low-pressure compressor are arranged in parallel on one rotor shaft, the air compressed by the low-pressure compressor is cooled by the intercooler to lower the temperature, and this is guided to the high-pressure compressor. Since it is further pressurized and sent to the engine, it is possible to pressurize the air in two stages with one supercharger, and with a compact structure without increasing the size of the supercharger, it should also have a high rotation speed. Without, the required high pressure ratio can be obtained.

Therefore, it is unnecessary to increase the rotation speed of the supercharger,
This suppresses an increase in stress on rotating members such as the rotor shaft, the compressor, and the turbine, and prevents the load on the bearing and the speed condition from becoming severe, thus preventing the bearing life from being shortened.

Further, the air after being pressurized by the low pressure compressor is cooled by the intercooler and is cooled to be sent to the high pressure compressor where it is pressurized and the high temperature air which has been lowered in temperature is supplied to the engine, It is possible to maintain the same high supercharger efficiency as in the case where two superchargers are installed side by side like the conventional one.

In the first means, the low-pressure compressor and the high-pressure compressor are arranged such that the high-pressure compressor is located near the bearing of the rotor shaft and the outlet sides of both are back to back. It is also one of the specific means of the present invention that the high pressure air passing through the high pressure compressor is configured to be supplied to the seal portion of the oil labyrinth.

According to such means, since the high pressure compressor and the oil labyrinth are adjacent to each other, the high pressure air passing through the high pressure compressor can be easily used as the air for sealing the oil labyrinth, and the sealing performance is improved.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view taken along a rotor axis of an exhaust gas turbine supercharger for a large diesel engine according to a first embodiment of the present invention.

In FIG. 1, 1 is a rotor shaft, 3 is a radial turbine fixed to one end of the rotor shaft 1 and driven by exhaust gas from an engine (not shown), and 7 is a turbine casing.

Reference numeral 21 denotes a low pressure stage radial compressor fixed to the other end of the rotor shaft 1, and 22 denotes a low pressure stage radial compressor 21 fixed to the rotor shaft 1 adjacent to the inside thereof (on the side of a plain bearing 4 described later). It is a high pressure stage radial compressor.

As shown in FIG. 1, the low-pressure stage radial compressor 21 and the high-pressure stage radial compressor 22 are arranged side by side so that the outlet sides are back-to-back, whereby the high pressure to the oil labyrinth 5, which will be described later, is increased. In addition to facilitating the supply of air, the coupling mode between the low-pressure casing 61 and the high-pressure casing 62, which will be described later, is compact and easy.

The central portion of the rotor shaft 1 has two sets of plain bearings 4
It is supported by the bearing box 8 via. 5 is the plain bearing 4
An oil labyrinth that is provided outside a plain bearing on the high pressure stage (described later) side and that seals the sliding portion between the plain bearing 4 and the rotor shaft 1 by supplying high pressure air to the inlet of the high pressure radial compressor 22. is there.

Reference numeral 61 denotes the low pressure stage radial compressor 2
1 is a low pressure casing having an air passage formed therethrough, and 62 is a high pressure casing having an air passage formed through the high pressure stage radial compressor 22. These casings are gas-sealed by bolts (not shown). Stick to each other.

Reference numeral 11 denotes an intercooler for cooling air, the air inlet of which is connected via the air pipe 12 to the low pressure casing 6 described above.
1, the air outlet is connected to the air inlet passage 15 of the high-pressure casing 62 via the air pipe 13.

During operation of the radial turbine type exhaust gas turbine supercharger constructed as described above, the exhaust gas from the engine (not shown) is guided to the turbine casing 7 and flows as shown by the arrow in FIG. The radial turbine 3 is driven and discharged to the exhaust pipe.

The driving force of the turbine 3 causes the low-pressure stage radial compressor 21 and the high-pressure stage radial compressor 22 to rotate via the rotor shaft 1. The air compressed by the low pressure radial compressor 21 is the air pipe 1
After passing through 2, it enters the intercooler 11, where it is heat-exchanged with a coolant such as cooling water to be cooled. Further, this cooled pressurized air enters the air inlet passage 15 of the high-pressure casing 62 through the air pipe 13, is subjected to the second-stage compression by the high-pressure radial compressor 22, and is supplied to the intake pipe of the engine or It is sent to a scavenging chamber (neither is shown).

FIG. 2 shows an exhaust gas turbine supercharger according to a second embodiment of the present invention. In this embodiment, an axial flow turbine 41 is provided instead of the radial turbine 3 in the first form shown in FIG. 71
Is the turbine casing. Other configurations are the same as those of the first embodiment shown in FIG. 1, and the same members are designated by the same reference numerals.

In the exhaust gas turbine supercharger according to the above embodiment, the high pressure and low pressure compressors are arranged in parallel on one rotor shaft 1 to compress the air in two stages, so that the structure is small and compact. In addition, a high pressure ratio can be obtained without increasing the turbine speed. Further, by avoiding higher rotation, the load and speed conditions applied to the bearing 4 are not severed, and the bearing life is secured.

Further, since the air pressurized and raised by the low pressure stage radial compressor 21 is cooled by the intercooler 11, the high pressure stage radial compressor 22 can send the cooled high pressure air to the engine. , High turbocharger efficiency can be obtained.

Further, the high pressure stage radial compressor 22
Since the oil labyrinth 5 and the oil labyrinth 5 are adjacent to each other, the high pressure air passing through the high pressure stage radial compressor 22 can be easily used as the air for sealing the oil labyrinth 5, and the sealing performance is improved.

[0028]

The present invention is configured as described above.
According to the invention of claim 1, high-pressure and low-pressure compressors are arranged in parallel on one rotor shaft, and the compressed air in the low-pressure compressor is cooled by the intercooler and pressurized by the high-pressure compressor. With a compact structure without increasing the size of the turbocharger, and without increasing the rotation speed, high pressure that maintains the same efficiency as the conventional two turbochargers. A ratio of exhaust gas turbine superchargers can be obtained.

Further, since it is not necessary to increase the rotation speed of the supercharger,
The increase in stress of the rotating member is suppressed, and the load condition of the bearing is prevented from becoming severe, so that the life of the bearing is prevented from being shortened.

According to the second aspect of the invention, the oil labyrinth can be sealed by the high pressure air passing through the high pressure stage compressor, and the sealing performance is improved.

[Brief description of the drawings]

FIG. 1 is a sectional view taken along a rotor axis of an exhaust turbine supercharger according to a first embodiment of the present invention.

FIG. 2 is an illustration corresponding to FIG. 1 according to a second embodiment of the present invention.

FIG. 3 is an FIG. 1 correspondence diagram showing an example of a conventional exhaust turbine supercharger.

[Explanation of symbols]

 1 Rotor Shaft 3 Radial Turbine 4 Plain Bearing 5 Oil Labyrinth 11 Intercooler 21 Low Pressure Stage Radial Turbine 22 High Pressure Stage Radial Turbine 41 Axial Flow Turbine 61 Low Pressure Casing 62 High Pressure Casing

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location F16J 15/447 F16J 15/447

Claims (2)

[Claims] 1. An exhaust gas turbine supercharger in which a turbine driven by exhaust gas from an engine is attached to one end of a rotor shaft, and a compressor for pressurizing air to the other end and sending the compressed air to the engine is fixed to the other end, The compressor comprises a low-pressure compressor for pressurizing air from the atmosphere and a high-pressure compressor for further pressurizing the compressed air by the low-pressure compressor, which are fixed to the rotor shaft. An exhaust gas turbine supercharger, characterized in that an intercooler for cooling air to the high-pressure compressor is provided in an air passage between the air inlet of the exhaust gas turbine and the air inlet. 2. The low-pressure compressor and the high-pressure compressor are arranged such that the high-pressure compressor is located closer to the bearing of the rotor shaft and the outlet sides of the two are back-to-back, and high-pressure air passing through the high-pressure compressor. The exhaust gas turbine supercharger according to claim 1, wherein the exhaust gas turbine supercharger is configured to supply the oil to the seal portion of the oil labyrinth.