JPS62165531A - Turbocharger - Google Patents

Abstract

PURPOSE:To provide the excellent supercharging performance covering a wider operating range by forming a radial turbine and a centrifugal compressor, which are for supercharging mainly in the high-speed region, and an axial turbine and an axial compressor, which are for supercharging mainly in the low-speed region, such that they are incorporated in a body. CONSTITUTION:A radial turbine 11, having a high expansion-ratio, and a centrifugal compressor 12, having a high pressure-ratio, are placed in a housing 15, which is provided with a turbine scroll 13 and a compressor scroll 14, and connected through a hollow shaft 18 to each other. In addition, on the downstream side from the turbine 11 is provided an axial turbine 19, and, on the upstream side from the centrifugal compressor 12 is provided an axial compressor 20 respectively. Said axial turbine 19 and said axial compressor 20 are connected through a rotating shaft 21, which is placed in the hollow shaft 18, to each other. And further, in the low-speed region and at the time of acceleration, supercharging is performed under a condition where the axial turbine 19 is rotated more speedily than the radial turbine 11, while, in the high-speed region, supercharging is performed by the high-speed rotation of the radial turbine 11.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a turbochart.

(Prior art) In order to improve the output of the engine, there is a turbocharger that supercharges the intake air using the exhaust energy of the ennon. (Refer to the 30th issue of the month).

To explain this based on Figure 2, Ennon's exhaust
An exhaust turbine 1 that rotates in response to air pressure and an intake compressor 2 that pressurizes intake air are connected via a common rotating shaft 3. As the engine rotates, the intake compressor 2 is also rotated, and the engine intake air is supercharged via the compressor scroll 5.

This intake compressor 2 is installed in the intake passage 7 on the upstream side of the throttle valve 6, and in order to prevent the discharge pressure (supercharging pressure) of the intake compressor 2 from exceeding a rising value, the exhaust is discharged when the discharge pressure reaches a predetermined value. The waste date valve 9 of the passage 8 bypassing the turbine 1 is opened so that part of the exhaust gas introduced into the exhaust turbine 1 from the exhaust passage 10 escapes.

(the problem that the invention seeks to solve),! 1. ) However, with such a conventional turbocharger, it is difficult to always maintain R-appropriate supercharging under a wide range of operating conditions.

For example, boost pressure? To the turbine scroll 4 so that the intercept point that reaches a predetermined value (maximum value) is in the Ennon low range! ? If the shape is set as the setting needle, the low-speed torque will improve, but the rotation of the exhaust turbine 1 will not increase in the high-speed range, resulting in a low torque.

Furthermore, since the moment of inertia of the turbochart is large, there is a time lag during acceleration etc. until the boost pressure reaches its maximum value.

The object of the present invention is to provide an excellent turbocharger that solves the above problem α.

(Means for Solving the Problems) This invention connects a high pressure ratio centrifugal compressor and a high expansion ratio porcelain turbine via a hollow shaft, and also provides a low pressure ratio molar turbine on the upstream side of the centrifugal compressor. The axial flow compressor and the axial flow turbine with a low expansion ratio are arranged downstream of the radial turbine. Connect via.

(Function) Therefore, when the engine is in a low speed range or when accelerating, the other-flow turbine rotates in succession to the radial turbine, and supercharging is mainly performed by the axial flow compressor, whereas in the high-speed range, the radial turbine It rotates at high speed and the centrifugal compressor begins to supercharge.

For this reason, each turbine and each compressor operate efficiently, ensuring sufficient supercharging from the low engine speed range to the high speed range, and achieving high supercharging responsiveness.

(Embodiment) FIG. 1 is a partial cross-sectional view showing an embodiment of the present invention.
12 is a high expansion ratio radial turbine, and 12 is a high pressure ratio centrifugal compressor.

The radial turbine 11 and centrifugal compressor 12 are composed of a turbine scroll 13 and a compressor scroll 1.
4, and the bearing 1G,
They are connected via a hollow shaft 18 supported by 17.

An axial turbine 19 is arranged downstream of the radial turbine 11, and an axial compressor 20 is arranged upstream of the centrifugal compressor 12.

The axial flow turbine 19 and the axial flow compressor 20 each include a rotating shaft 21 that passes through the hollow shaft 18 and is arranged concentrically.
The rotating shaft 21 is connected to the radial turbine 11 via
and a bearing 22 fitted between the centrifugal compressor 12
, 23.

Between the radial turbine 11 and one axial flow turbine, there is a /zzle 24 having a predetermined blade shape that guides the flow of exhaust gas that has passed through the radial turbine 11 to the axial flow turbine 19, and between the centrifugal compressor 12 and the axial flow compressor 20. Stators 25 each having a predetermined blade shape are provided to adjust the flow of intake air that has passed through the axial compressor 20 and guide it to the centrifugal compressor 12.

Further, the axial flow turbine 19 and the axial flow compressor 20 are set to have a lower expansion ratio and a lower pressure ratio than the radial turbine 11 and the centrifugal compressor 12. In this case, the axial flow turbine 19 is an impulse turbine in which the discharge pressure of the radial turbine 11 is not increased as much as possible with the /zuru 24, that is, the degree of reaction is close to zero.

Note that 6 is an intake passage ' downstream of the compressors 12 and 20.
7 is a throttle valve installed, 9 is a turbine 11.19
9 is an estdate valve installed in the passage 8 that bypasses the.

With this configuration, the radial turbine 1
1 rotation is not so earthy, but the downstream axial flow turbine V
The engine 19 efficiently maintains sufficient rotation due to its low j expansion ratio.

Therefore, a predetermined supercharging is performed by the axial flow compressor 20 that works in conjunction with the axial flow turbine 19, and good torque can be ensured from the low speed range to the partial load range.

Then, when the engine enters a high speed range or a high load range and the exhaust gas volume increases, the radial turbine 11 rotates at a high speed, and the centrifugal condenser 12 performs supercharging accordingly.

Therefore, sufficient supercharging can be obtained even in high-speed, high-load ranges, and full-open torque can be improved.

Further, during acceleration, the rotation of the axial flow turbine 11 and the axial flow compressor 12, which are lightweight and have a small moment of inertia, increases in a responsive manner to provide supercharging, thereby improving the time lag and providing good acceleration response.

In addition, each turbine 11, 19, each compressor 12.20
Since they are arranged concentrically, they can be housed integrally in the nozzle 15, and the structure is simplified.

(Effects of the Invention) As described above, according to the present invention, radial turbines and centrifugal compressors that perform supercharging mainly in high speed ranges, and axial flow turbines and axial flow compressors that perform supercharging mainly in low speed ranges. Since it is integrally constructed, it is possible to obtain excellent rL supercharging performance as a turbocharger from a low engine speed range to a high speed range, and to ensure high acceleration response. Also,
The structure is simple.

[Brief explanation of drawings]

FIG. 1 is a partial cross-sectional view showing an embodiment of the present invention, and FIG. 2 is a partial cross-sectional view of a conventional example. DESCRIPTION OF SYMBOLS 11... Radial turbine, 12... Centrifugal compressor, 18... Hollow shaft, 19... Axial flow turbine, 2
0... Axial flow fan presser, 21... Rotating shaft. Patent Applicant: Nissan Automobile Il1 System Corporation□Personal Agent: Patent Attorney: Masaki Goto (1 other name) Figure 1 Figure 2

Claims (1)

[Claims] A high pressure ratio centrifugal compressor and a high expansion ratio radial turbine are connected via a hollow shaft, and a low pressure ratio axial flow compressor is installed upstream of the centrifugal compressor, and a low expansion ratio shaft is installed downstream of the radial turbine. What is claimed is: 1. A turbocharger, characterized in that the axial flow compressor and the axial flow turbine are connected to each other via a rotary shaft that passes through the hollow shaft and is arranged concentrically.