JPS59122726A - Turbine scroll of turbo-charger - Google Patents

Abstract

PURPOSE:To prevent reduction of the turbine efficiency due to formation of the stagnant region in a supplementary exhaust passage at the time of the low speed operation of a turbine rotor by providing a communication part between the external peripheral part of a main exhaust passage which has the opening part oriented to the inlet of the turbine rotor and the external peripheral part of the supplementary exhaust passage which is arranged in parallel with said main passage. CONSTITUTION:A turbine scroll 13 has a main exhaust passage 13A which has an opening part 14 oriented to the inlet 1A of a rotor 1 and a supplementary exhaust passage 13B which is arranged in parallel wherewith via a partition wall 5B. A communication part 15 is continuously formed with a constant width B around both the external peripheries of the main exhaust passage 13A and the supplementary exhaust passage 13B along the inner peripheral face of a scroll housing 5 from the narrowest passage part of the tongue part 16 of the supplementary exhaust passage 13 on the side of the rotor 1 to the throat part 17 which is formed by the tongue part 16 and the housing 5. As a result, when an opening/closing valve 18 is closed at the slow running of a turbine, the supplementary exhaust passage 13B is separated by the partition wall 5B and therefore will not be opened to the inlet 1A, hence preventing the influence caused by the stagnant region.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a turbine scroll for a turbocharger, and more particularly to a turbine scroll in which the displacement fft supplied to the exhaust turbine is made variable at the scroll inlet depending on the operating state of the engine.

FIG. 1 shows an example of a conventional turbine scroll with a variable capacity of this type, and this example is shown in U.S. Patent Publication No. 32-11. This is disclosed in No. 233. Here, l is a turbine rotor that is directly connected to a compressor impeller (not shown) by a rotor shaft, and a spiral passage turbine scroll 3 is provided on the outer periphery of the turbine rotor l. Exhaust gas from the displacement Its is guided O Furthermore, in the turbine scroll 3 of this example, its housing! The large exhaust passage section 3A and the small exhaust passage section 3B form a spiral chamber, and these passage sections 3A and 3B are connected to the inlet of the rotor l. It is opened towards part/A.

Reference numeral 6 denotes an on-off valve provided on the large exhaust passage 3A side at the part of the exhaust passage connected to the inlet JC of the scroll 3. This on-off valve B controls the volume μ of exhaust gas flowing into the large exhaust passage 3A. It can be changed. 7 is an exhaust gas outlet.

In the turbine scroll 3 configured in this manner, when the engine is in a low speed rotation region, there is a question of compatibility between the turbocharger and the engine. In order to maintain good low-speed supercharging characteristics at 7M, it is necessary to reduce the gas passage area, for example, by operating the on-off valve 6 by a control mechanism (not shown) that uses supercharging pressure. , the gas volume passing through the large exhaust passage 3A! k can be adjusted. Furthermore,
When the engine is in the high speed rotation area, the large exhaust passage 3A
Gas is supplied to the rotor from both the small exhaust passage Jf3 and the small exhaust passage Jf3.

However, in the turbine scroll 3 in which the gas capacity supplied to the rotor is variable as described above, both the large exhaust passage 3A and the small exhaust passage 3B are shaped to open toward the rotor inlet portion/A, and further, Since the gas flow rate of the large exhaust passage 3A is configured to be throttled by the on-off valve B, when the gas supply to the large exhaust passage 3A is cut off by the on-off valve B in the low speed rotation region of the engine, this large exhaust passage A dead water area occurs at 3A.

However, in such a state, gas flows into the small exhaust passage 3B.
is supplied from the rotor inlet /A to the rotor /, and at this time, a swirling flow /θ as shown in FIG. The gas fluid forming io will have centrifugal force. A part of the gas fluid is then dispersed across the width of the gas body, which is the dead water region of the large exhaust passage 3A, thereby generating a circulation flow shown in FIG. 2(B). As this circulating flow // flows along the wall surface of the large exhaust passage 3A, it loses energy due to friction loss, and then merges with the swirling flow /θ again, resulting in a large energy loss within the turbine scroll 3, resulting in turbine efficiency. resulting in a decrease in

Furthermore, FIG. 3 shows a commonly used double entry housing type scroll 3, in which the housing 5 is divided in the axial direction by a wall &A projecting from the outer periphery.

Therefore, in such a double entry valve type scroll 3, either one of the exhaust passages 3D
Even if an on-off valve (not shown) is provided to open and close the valve, a similar phenomenon will occur, resulting in lower efficiency than in the case of a single-entry turbine scroll, and the turbo boost pressure at low speeds will decrease. Makes the start-up worse.

The purpose of the present invention is to focus on the above-mentioned problems, and to effectively utilize exhaust energy from low speed to high speed engine speeds, reduce loss, maintain good turbine efficiency, and further reduce engine backlash. An object of the present invention is to provide a turbine scroll for a turbocharger that contributes to maintaining sufficient high-speed output through the effect of lowering pressure. It has a main exhaust passage and a spiral auxiliary exhaust passage which is arranged in parallel with the main exhaust passage and does not open directly into the rotor inlet, and a communication hole having a constant width over almost the entire circumference of the rotor is formed between the outer peripheries of both exhaust passages. In addition, an on-off valve is provided on the engine/exhaust passage side that connects to the auxiliary exhaust passage, so that even when the on-off valve is closed, exhaust gas is always supplied to the rotor inlet through the opening of the main exhaust passage. do.

The present invention will be described in detail below based on the drawings.

FIG. 9 shows an embodiment of the present invention, where /3 is a turbine scroll and A1. /, 3 A is scroll /3
The main exhaust passage is spiral-shaped. The main exhaust passage 13A has an opening llI facing the inlet part /A of the quadrature, and is between this main exhaust passage /3A and an auxiliary exhaust passage /3B provided in parallel via a partition wall 3B. has a communication part /S.

However, this communication department/! 8r is continuously provided at a position along the inner circumferential surface of the scroll housing 3 as shown in No. 31 (A), and the width B of the groove-shaped communication portion /S is constant, and the communication The area where part/S is provided is from the smallest passage of the rotor L in the tongue part/B of the scroll 13 to the throttle part, that is, the throat part formed by the tongue part/A and the housing S. However, depending on the design If it is not possible to provide the communication part /3 continuously in this range as shown in FIG. 3 due to top or structural reasons, the range where the communication part /3 is not provided is made as short as possible and the inlet part /3 of the turbine rotor l is not provided. The increase in loss due to non-uniformity of the channel structure in A is suppressed.

7g is the entrance part of scroll/3/? Auxiliary passage of exhaust passage q connecting with C/? This is an on-off valve provided on the B side, and is opened and closed via a control mechanism and a drive mechanism (not shown).
to close it.

The width B'fr of the communication portion /3 is determined by the following formula as a condition that the inventor of the present invention has confirmed to obtain the best supercharging characteristics.

However, in equation (1), AAT: main exhaust passage/,? Restricted portion of A/area at A - ABT: Area at auxiliary exhaust passage/restricted portion of 3B/'7B RA: Distance from rotor center O to the center of gravity of constricted portion/7 RB: From rotor center 0 to constricted portion/' 7B Distance H to the center of gravity: If the width B of the communication part 15 needs to taper downstream due to design reasons, etc., depending on the blade width at the artificial part /A of the turbine rotor, the above conditions should be met. With this in mind, consideration must be given to minimizing losses as much as possible.

In the turbine scroll/3 configured in this way, when the on-off valve/g is closed in the low speed rotation region of the engine, a dead water area is generated in the auxiliary exhaust passage/3B, but the auxiliary exhaust passage/3B has a partition wall, Main exhaust passage/J by tB
Since it is separated from A, it is not opened toward the inlet part /A of rotor l, and therefore the auxiliary exhaust passage /,? B
The flow described in (4th body) and (B) does not occur on the side. Thus, although the communication part /S exists, the main exhaust flow is limited to the main exhaust passage /3A and flows into the rotor l, as if there were a partition w left B in this part /S. go.

Therefore, the rise characteristics of the supercharging pressure in the low speed rotation region are similar to those of a single entry turbine scroll having a small throttle area, and good low speed supercharging characteristics can be maintained.

Furthermore, after the boost pressure rises and reaches a predetermined pressure, the on-off valve /g begins to open via a control mechanism that utilizes the boost pressure, etc., so that the main exhaust passage /3A and the auxiliary exhaust Exhaust gas is guided to both passageways/3B, but the exhaust gases guided to the auxiliary exhaust passageway/jB flow into the main exhaust passageway/JA side via the communication part/left, and are then routed to the main exhaust passageway/3A side. and is guided to the rotor.

In particular, the communication part/left is provided along the inner circumference of the scroll/3, and is the part where the flow velocity is slowest within the scroll/3, so from the auxiliary exhaust passage/JB side to the main exhaust passage/, The loss when the exhaust gas mixes into the A side is kept to a minimum, and even in the high-speed rotation region, that is, when the flow rate of the exhaust gas is large, there is no problem with the decrease in efficiency due to the exhaust gas passing through the communication hole /S. Therefore, good supercharging characteristics can be maintained.

As described above, according to the present invention, there is provided a winding-shaped main exhaust passage that opens directly toward the turbine sorter inlet, and an auxiliary exhaust passage that is arranged in parallel to this and does not open to the rotor inlet. Therefore, between the outer peripheral parts of both exhaust passages, the outer peripheral wall forms a communication part through which gas can flow from the position of the tongue part closest to the rotor to the position of the throat part, and communicates with the auxiliary exhaust passage. An on-off valve is installed in the engine exhaust passage.
In the low speed range of the engine, this on-off valve was operated to supply exhaust gas mainly to the rotor through the main exhaust passage, so even at low speeds, energy was lost due to the dead water produced in the auxiliary exhaust passage. There is no possibility that the condition will be carried into the rotor, an appropriate boost pressure can be supplied, and good turbine efficiency can be obtained.

Furthermore, even at high speeds, the exhaust gas can be guided directly to the rotor for supercharging, so there is less loss of exhaust energy and the back pressure of the engine can be lowered, which of course contributes to high-speed output. Nor.

In addition, in the above explanation, the partition wall is configured to be a surface perpendicular to the rotation axis, but depending on the spiral shape of the scroll to be set, the partition wall does not necessarily have to be a surface perpendicular to the rotation axis. The surface may be tilted more than this.

[Brief explanation of drawings]

No. 1rXJ shows an example of the configuration of a conventional variable capacity turbine scroll; FIG.
4) is its A-AM4 sectional view, and Figure S (B) is the No. 1 kite]
FIG. l...Turn rotor, /A...inlet section, K...shaft, 3, /3...turbine scroll 1. 7A, , 7B, da... exhaust passage, 3C, /3C.
...Inlet section, S...Housing, sh...Wall, 6, /Za...Opening/closing valve, 7...Gas outlet, 10...Swirling flow, /C...Circulating flow, /, ? A, /, 7B... Exhaust blood path, /lI... Opening, /S... Communication portion, /6... Tongue, /7. /7A, /? B...Aperture part. Figure 1 Figure 2 (B) Figure 3

Claims (1)

[Claims] It has a spiral main exhaust passage having an opening facing the turbine rotor inlet, and an auxiliary exhaust passage that is arranged in parallel with the main exhaust passage and is isolated from the turbine rotor inlet. A valve that provides a communication portion over approximately the entire circumference of the turbine rotor between an outer circumferential portion and an outer circumferential portion of the main exhaust passage to allow exhaust gas to freely flow and to vary the amount of exhaust gas supplied to the auxiliary exhaust passage; A control mechanism that operates the valve according to the operating state of the engine closes the auxiliary exhaust passage in a low speed rotation region of the engine and supplies the exhaust gas to the turbine rotor only through the main exhaust passage. A turbine scroll of a turbocharger characterized by: