JPH074395A - Exhaust turbosupercharger - Google Patents

Abstract

PURPOSE:To provide an exhaust turbosupercharger allowing the low speed performance of an engine to be improved without exhaust interference and preventing the load increase of a variable nozzle part and a turbine moving blade and the degradation of engine efficiency. CONSTITUTION:An exhaust turbosuperchager has a turbine moving blade 1, a variable nozzle 2 provided around the turbine moving blade 1, a spiral scroll part 3 surrounding the variable nozzle 2, and an exhaust gas lead-in part 10 for leading exhaust gas to a throat 4 for supplying exhaust gas to the scroll part 3 from the exhaust manifold of an engine. The exhaust gas lead-in part 10 is formed of two lead-in passages 12 for leading exhaust gas from the different cylinders of the engine. These two lead-in passages 12 are partitioned by a division plate 14 extended as far as in front of the throat 4 from a connecting part 13 to the exhaust manifold, and passage areas at the ends of two lead-in passages are respectively smarter than the passage area of the connecting part 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust turbine supercharger, and more particularly to an exhaust turbine supercharger having a variable nozzle.

[0002]

2. Description of the Related Art An exhaust turbine supercharger is a device for rotating a turbine at high speed by the exhaust gas of an engine and driving a supercharging blower with this turbine, in order to increase the output and efficiency of the engine. Widely used in. An exhaust turbine supercharger provided with a variable nozzle is provided with a variable nozzle 2 upstream of a turbine rotor blade 1 as shown in FIG. 6, for example, and improves low speed performance while maintaining high speed performance. be able to. That is, when the engine exhaust speed is low and the engine speed is low, the variable nozzle narrows the nozzle (reduces the nozzle flow passage area) to speed up turbine rotation to increase boost pressure and improve engine low speed performance. be able to.

[0003]

However, in the exhaust turbine supercharger equipped with such a variable nozzle, if the nozzle is throttled to a certain extent or more, the turbine inlet pressure (that is, the exhaust pressure of the engine) rises, and the adjacent ignition cylinders. There was a problem that blowback (so-called exhaust interference) occurred, and even if the nozzles were throttled further, the performance of the engine deteriorated. Therefore, there is a problem that the adjustable range of the variable nozzle is narrow and the low speed performance of the engine cannot be improved any further. In order to prevent this exhaust interference, for example, as shown in FIG.
There is proposed and partially used a supercharger in which the upstream scroll portion 3 is divided into two by a scroll blade 3a in the circumferential direction to separate the exhaust gas of the adjacent ignition cylinders.
However, in such a supercharger, since the exhaust gas of each cylinder of the engine is transmitted as it is, the pressure fluctuation due to the pulse of the exhaust gas is large, the load on the variable nozzle 2 and the turbine rotor blade 1 is large, and the damage due to the blade vibration or There was a problem that problems such as wear could occur. Scroll blade 3a
The (partition wall) causes a problem that the wall friction loss of the fluid increases and the engine efficiency deteriorates.

The present invention was devised to solve such problems. That is, an object of the present invention is to provide an exhaust turbine supercharger equipped with a variable nozzle that can improve the low-speed performance of an engine without exhaust interference, do not increase the load on the variable nozzle portion and turbine rotor blades, and do not deteriorate engine efficiency. To provide.

[0005]

According to the present invention, a turbine rotor blade, a variable nozzle provided around the turbine rotor blade, a spiral scroll portion surrounding the variable nozzle, and an exhaust manifold of an engine are provided. To the throat for supplying exhaust gas to the scroll portion, and an exhaust gas turbocharger having an exhaust gas introduction portion that guides exhaust gas to the throat, wherein the exhaust gas introduction portion includes two introduction passages that introduce exhaust gas from cylinders of different engines The two introduction passages are partitioned by a dividing plate extending from a connection portion with the exhaust manifold to the front of the throat, and flow passage areas at ends of the two introduction passages are smaller than connection passage passage areas. An exhaust turbine supercharger is provided. According to a preferred embodiment of the present invention, the sum of the two end channel areas is larger than the throat channel area. Further, it is preferable that the end channel area is 40 to 90% of the connection channel area, and the sum of the two terminal channel areas is 0 to 60% larger than the throat channel area. . Also,
The minimum flow passage area of the variable nozzle is smaller than the inlet flow passage area of the turbine rotor blade, and the throat flow passage area is substantially the same as or larger than the maximum flow passage area of the variable nozzle,
An end of the introduction passage is adjacent to the throat,
It is preferable.

[0006]

According to the above-described structure of the present invention, the exhaust gas introducing portion is composed of two introducing passages for guiding the exhaust gas from the cylinders of different engines, and only the two introducing passages are connected to the exhaust manifold and the throat. It is partitioned by a dividing plate extending to the front, and the end passage areas of the two introduction passages are smaller than the connection passage area. This exhaust gas introduction portion functions as a so-called pulse converter, and exhaust gases from different cylinders have it. Pulse energy can be converted to velocity energy. Therefore, so-called exhaust interference does not occur even if the variable nozzle is narrowed down compared to the conventional one, the adjustable range of the variable nozzle can be widened, and the low speed performance of the engine can be improved. Further, since the pulse energy of the exhaust gas is converted into the velocity energy, the pressure fluctuation in the scroll portion is small and the load on the variable nozzle portion and the turbine rotor blade does not increase. Moreover, since there is no scroll blade (partition wall) in the scroll part and the division plate (partition wall) of the exhaust gas introduction part is short, the wall loss of the fluid wall hardly increases and engine efficiency is not deteriorated. Therefore, due to the compact structure, it is possible to reduce fluctuations in exhaust gas pressure reaching the variable nozzle portion and the rotor blades to substantially eliminate vibration stress and wear, and to reduce wall friction loss of fluid to improve engine performance. .

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a partial cross-sectional view of a turbine side of an exhaust turbine supercharger according to the present invention, and FIG. 2 is A- of FIG.
It is sectional drawing in the A line. 1 and 2, an exhaust turbine supercharger according to the present invention includes a turbine rotor blade 1,
Variable nozzle 2 provided around the turbine rotor blade 1.
And a scroll-shaped scroll portion 3 surrounding the variable nozzle 2.
And an exhaust gas introducing portion 10 for guiding exhaust gas from an exhaust manifold (not shown) of the engine to the throat 4. The tongue-shaped partition wall provided at the connecting portion between the scroll portion 3 and the exhaust gas introducing portion 10 is referred to as a tongue portion 5.
The part with the narrowest cross section that passes through the tip of is the throat 4,
It serves to supply the exhaust gas to the scroll portion 3. The minimum flow passage area of the variable nozzle 2 is smaller than the inlet flow passage area of the turbine rotor blade 1, and the flow passage area of the throat 4 is substantially the same as or larger than the maximum flow passage area of the variable nozzle 2. As a result, the exhaust gas can be supplied to the turbine rotor blade 1 from the throat 4 via the variable nozzle 2 by minimizing the energy loss, and the direction and speed of the exhaust gas flowing into the turbine rotor blade 1 can be effectively controlled. be able to. The exhaust gas introduction part 10 is composed of two introduction passages 12 for introducing exhaust gas from different cylinders of the engine (see FIG. 2),
The two introduction passages 12 are partitioned by a dividing plate 15 extending from a connection portion 13 with the exhaust manifold to a front end 14 of the throat 4. The flow passage areas of the two introduction passages 12 at the terminal end 14 are smaller than the connection portion flow passage area, and are 40 to 90% of the connection portion flow passage area in the illustrated example. As a result, the exhaust gas introduction unit can function as a so-called pulse converter, and the pulse energy of exhaust gas from different cylinders can be effectively converted into velocity energy. The sum of the flow passage areas of the two introduction passages 12 at the end 14 is larger than the flow passage area of the throat 4, which is 0 to 60% larger in the illustrated example. Further, the terminal end 14 of the introduction passage 12 is adjacent to the throat 4 in consideration of the passage shape and the flow loss due to friction. As a result, the exhaust gas passing through the end 14 of the introduction passage 12 can be supplied to the throat 4 without energy loss.

3 to 5 are diagrams showing the performance of the exhaust turbine supercharger according to the present invention. Hereinafter, these figures will be described. FIG. 3 is a diagram showing the relationship between the rotation speed Nt (horizontal axis) of the turbine blade 1 and the vibration frequency F (vertical axis) generated in the turbine blade. The vibration stress amplitude in the conventional supercharger is indicated by a broken circle. And the vibration stress amplitude in the supercharger of the present invention is shown by the size of the solid line circle. As shown in this figure, the present invention reduces the vibration stress generated in the turbine blade. FIG. 4 is a diagram showing pressure fluctuations at the inlet of the variable nozzle 2, where the horizontal axis represents time t, the vertical axis represents pressure fluctuations P, the broken line is the conventional supercharger, and the solid line is the supercharger according to the present invention. Showing the machine. As is clear from this figure, the pressure fluctuation width is small in the supercharger of the present invention, and the load on the variable nozzle portion and the turbine rotor blade is greatly reduced. FIG. 5 shows the fuel consumption rate S with respect to the engine speed Ne (horizontal axis).
FIG. 8 is a performance characteristic diagram in which the vertical axis represents FC, turbine blade rotation speed Nt, exhaust gas flow rate Q, and supercharging pressure Pb, in which the broken line indicates the conventional supercharger of the type shown in FIG. 7, and the solid line indicates this. 1 shows a supercharger of the invention. As is clear from this figure, in the supercharger of the present invention, the fuel consumption rate SFC is low, the turbine blade rotation speed Nt, the exhaust gas flow rate Q, and the supercharging pressure Pb are all large, especially in the high speed region of the engine. It has excellent performance characteristics. Further, it can be seen that even in the low speed region, the difference in the fuel consumption rate SFC is small, but the other performances are superior to those of the conventional supercharger.

[0009]

As described above, according to the structure of the present invention, the exhaust gas introducing portion is composed of the two introducing passages for guiding the exhaust gases from the cylinders of different engines, and only the two introducing passages are the exhaust manifold and the exhaust manifold. Is divided by a dividing plate extending from the connection part to the front of the throat, and the flow passage areas of the ends 14 of the two introduction passages are smaller than the connection portion flow passage area.
Therefore, the exhaust gas introducing portion functions as a so-called pulse converter, and the pulse energy of exhaust gas from different cylinders can be converted into velocity energy. Therefore,
Even if the variable nozzle is narrowed down compared to the conventional one, so-called exhaust interference does not occur, the adjustable range of the variable nozzle can be widened, and the low speed performance of the engine can be improved. Further, since the pulse energy of the exhaust gas is converted into the velocity energy, the pressure fluctuation in the scroll portion is small and the load on the variable nozzle portion and the turbine rotor blade does not increase. Moreover, since there is no scroll blade (partition wall) in the scroll part and the division plate (partition wall) of the exhaust gas introduction part is short, the wall loss of the fluid wall hardly increases and engine efficiency is not deteriorated.

That is, according to the present invention, the compact structure can improve the low speed performance of the engine without exhaust interference, and the load of the variable nozzle portion and the turbine rotor blade does not increase and the engine efficiency does not deteriorate. The effect can be obtained.

[Brief description of drawings]

FIG. 1 is a turbine-side partial sectional view of an exhaust turbine supercharger according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a diagram showing a relationship between a rotational speed of a turbine blade (horizontal axis) and a frequency (vertical axis) generated in the turbine blade.

FIG. 4 is a diagram showing pressure fluctuations at the inlet of the variable nozzle.

FIG. 5: Fuel consumption rate S for engine speed (horizontal axis)
FIG. 4 is a performance characteristic diagram showing FC, turbine blade rotation speed Nt, exhaust gas flow rate Q, and boost pressure Pb.

FIG. 6 is a configuration diagram of an exhaust turbine supercharger including a conventional variable nozzle.

FIG. 7 is another configuration diagram of an exhaust turbine supercharger including a conventional variable nozzle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Turbine rotor blade 2 Variable nozzle 3 Scroll portion 4 Throat 5 Tongue portion 10 Exhaust gas introduction portion 12 Introduction passage 13 Connection portion 14 Terminal 15 Dividing plate

Claims (4)

[Claims] 1. A turbine rotor blade, a variable nozzle provided around the turbine rotor blade, a spiral scroll portion surrounding the variable nozzle, and a throat for supplying exhaust gas from an exhaust manifold of an engine to the scroll portion. An exhaust gas turbocharger having an exhaust gas guide section for guiding exhaust gas to the exhaust gas turbocharger, wherein the exhaust gas guide section includes two introduction paths for guiding exhaust gas from cylinders of different engines, and the two introduction paths are an exhaust manifold and The exhaust turbine supercharger is characterized in that the flow passage areas at the ends of the two introduction passages are smaller than the connection portion flow passage areas, respectively, and are partitioned by a dividing plate extending from the connection portion to the front of the throat. 2. The exhaust turbine supercharger according to claim 1, wherein the sum of the two end flow passage areas is larger than the throat flow passage area. 3. The end channel area is 40 to 90% of the connection channel area, and the sum of two terminal channel areas is 0 to 60% larger than the throat channel area. The exhaust turbine supercharger according to claim 2, wherein 4. The minimum flow passage area of the variable nozzle is smaller than the inlet flow passage area of the turbine blade, and the throat flow passage area is substantially the same as or larger than the maximum flow passage area of the variable nozzle. The exhaust turbine supercharger according to claim 3, wherein an end of the introduction passage is adjacent to the throat.