JPS60230515A - Exhaust energy recovering turbine - Google Patents

Abstract

PURPOSE:To offset generated thrust and reduce mechanical loss by fixing two turbine blades whose generating quantity is nearly equal, on one shaft, being faced against each other, and branching an exhaust gas into casings having each turbine blade. CONSTITUTION:Turbine blades 2A, 2B whose outputs are nearly equal, are provided, being faced against each other, on both sides of a shaft 3 on which a power recovering gear mechanism 4 is fixed, and housed in casings 6A, 6B respectively. Air feeding ports 7A, 7B are connected by a connecting pipe, and the exhaust gas of an engine is branched and fed as shown by the arrow A, drives each of the turbine blades 2A, 2B simultaneously, and is discharged from exhaust ports 9 as shown by the arrow B. A thrust bearing 5A is provided on the shaft 3. Thereby, leftward thrust is generated on the turbine blade 2A, and rightward thrust is generated on the turbine blade 2B, and, since both thrusts mutually offsets, an axial thrust can be prevented from generating in the shaft 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in a turbine for recovering energy contained in engine exhaust gas.

[Prior art]

Engine exhaust gas contains a large amount of energy,
In order to make effective use of this and improve air supply efficiency, a method of driving a turbocharger has been adopted.

On the other hand, an exhaust energy recovery turbine is employed to directly recover the energy contained in the exhaust gas as part of the power.

As shown in FIG. 3, this exhaust energy recovery turbine is constructed by providing a gear mechanism 4 on a shaft 3 that supports the turbine blades 2 of the turbine 1, and connecting the gear mechanism 4- to the output shaft system of the engine. The system is configured to receive power from the exhaust gas and recover the energy from the exhaust gas as power.

Exhaust gas flows into the turbine 1 through the air supply port IA as shown by arrow A.
When the gas is supplied from the exhaust gas, drives the turbine blade 2, and is exhausted from the exhaust port IB as shown by arrow B, a thrust S is generated that pushes the turbine blade 2 in the opposite direction to this exhaust gas. A thrust bearing 5 is provided for receiving.

FIG. 4 is a diagram plotting the exhaust gas pressure P on the vertical axis and the turbine rotational speed N on the horizontal axis.
The rotational speed of the turbine blade 2 is determined according to this, and the thrust S is generated accordingly. This thrust S is quite large, and therefore the thrust bearing 5 has to be large.

Therefore, the mechanical loss in the thrust bearing 5 is normally 5 to 7%, and the mechanical loss in the energy recovery turbine is as high as 10%, making the efficiency of recovering exhaust gas energy extremely low. This will result in a decline.

[Purpose of the invention]

The present invention provides an exhaust energy recovery turbine that minimizes the mechanical loss due to the thrust generated in the conventional turbine that recovers the energy contained in the exhaust gas of the engine.

[Summary of the invention]

The configuration of the present invention for achieving the above object is such that two turbine blades are fixed to one shaft in opposite directions, and the exhaust gas of the engine is divided into a casing having the turbine blades. This is an exhaust energy recovery turbine.

〔Example〕 Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view showing a first embodiment of the present invention, in which tanibine blades 2A and 2B with approximately the same output are provided on both sides of a shaft 3 to which a gear mechanism 4 for power recovery is fixed. The turbine blades 2A, 2B are housed in the casings 6A, 6B and the air supply ports are installed. A and 7B are connected by a connecting pipe 8, engine exhaust gas is divided and supplied as shown by arrow A, the turbine blades 2A and 2B are simultaneously driven, and exhaust gas is exhausted from an exhaust port 9 as shown by arrow B. Further, the shaft 3 is provided with a thrust bearing 5A for receiving thrust generated therein.

In this embodiment, two exhaust gas turbines Ta and Tb having the same rotation speed and output are fixed on a shaft 3 so that their respective turbine blades 2A and 2B are oriented in opposite directions, and these turbine Ta , Tb are supplied with exhaust gas in a branched manner, and the energy of the exhaust gas is directly extracted as motive power via a gear mechanism 4 provided on the shaft 3.

In this way, the two turbines Ta have the same rotation speed and output,
one shaft 3 so that the thrusts of Tb are in opposite directions
By arranging it above to form a turbine and supplying exhaust gas in a divided manner, a leftward thrust is generated in the turbine blade 2A, and a rightward thrust is generated in another turbine blade 2B. , both thrusts have the same size or almost the same size, and only differ in direction, so both thrusts cancel each other out, and there is virtually no thrust that moves the shaft 3 in its axial direction. It turns out.

Therefore, in the exhaust energy recovery turbine according to the present invention, the thrust bearing 5A may be miniaturized.

FIG. 2 is a sectional view showing a second embodiment, and in the embodiment of FIG. 1, the turbine blades 2A of the turbine Ta and the turbine blades 2B of the turbine Tb are back to back, so the exhaust port However, in this embodiment, two turbine blades 2A and 2B of two turbines T'a and Tb are required.
The casings 6A, 6B are further connected by an exhaust pipe 10, and a common exhaust port 9 is provided between the casings 6A, 6B.

In addition, in a device with this structure, since the shaft 3 passes through the inside of the exhaust pipe 10, the shaft 3 is required to have heat resistance.
Depending on the construction of the casing, the shaft 3 can be located outside the exhaust gas flow and not exposed to this heat.

The first embodiment and the second embodiment differ only in the arrangement of the gear mechanism 4 for recovering power and the exhaust pipe 9.
Although there is not much difference in terms of operation and effect, either structure is adopted depending on the position of the route for recovering power and the arrangement of the exhaust pipe 9.

〔Effect of the invention〕

The present invention provides a turbine for recovering the energy of exhaust gas from an engine, in which two turbine blades having substantially the same output are fixed to one shaft in opposite directions, and the exhaust gas from the engine is transferred to the turbine blades. The structure is such that the flow is divided into a casing that surrounds the casing.

Therefore, according to the turbine according to the present invention, the substantially identical thrusts generated by the two turbine blades being simultaneously driven by the exhaust gas are in opposite directions and therefore cancel each other out.

Therefore, the thrust bearing 5A that supports the shaft 3 can be downsized, and the loss of mechanical energy can be reduced accordingly, so that the energy of the exhaust gas can be recovered with less loss. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the main parts of an exhaust energy recovery turbine according to a first embodiment of the present invention, FIG. 2 is a sectional view showing the second embodiment, and FIG. 3 is a sectional view showing a conventional exhaust energy recovery turbine. A sectional view showing the energy recovery turbine, FIG. 4 is a characteristic diagram of the turbine shown in FIG. 3. 1... Turbine, IA... Air supply port, IB... Exhaust port, 2.2A, 2B... Turbine blade, 3... Shaft 4.
...Gear mechanism, 5,5A...Thrust bearing, 6A,6
B...Casing, 7A, 7B...Air supply port, 8...
- Connecting pipe, 9...exhaust port, 10...exhaust pipe. Agent: Patent Attorney Shin Ogawa − Patent Attorney Ken Noguchi Teru Patent Attorney Kazuhiko Saishita Figure 1 Figure 3 Figure 2 Figure 4

Claims (1)

[Claims] An exhaust energy recovery turbine configured to have two turbine blades having substantially the same amount of thrust generated in opposite directions fixed to a single shaft so that exhaust gas is divided into a casing having the turbine blades.