JPS6240094Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a new turbocharger, and in particular,
A partition plate is installed inside the scroll part to automatically control exhaust pulsation in response to the temperature of the exhaust gas, which changes according to the increase or decrease in the flow rate of exhaust gas emitted by the internal combustion engine.
The present invention relates to a turbocharger that can improve the low-speed torque and fuel efficiency of an internal combustion engine by increasing the supercharging pressure during low-speed rotation when the exhaust gas flow rate decreases.

[Prior Art] In general, a turbocharger rotates a turbine wheel at high speed using exhaust gas from an internal combustion engine, and drives a compressor installed coaxially with the turbine wheel to compress intake air and power the internal combustion engine. It is designed to supercharge to a predetermined pressure.

As shown in FIG. 1, the turbine casing 1 is comprised of a scroll portion 3 surrounding the turbine impeller 2, and an exhaust gas introduction passage portion 4 through which exhaust gas is introduced into the scroll portion 3. The scroll part 3 is set under predetermined conditions so that the exhaust gas introduced therein supplies a uniform operating flow velocity to the turbine wheel 2 along its circumferential side,
It is formed into a spiral shape whose cross-sectional area S is successively reduced.

By the way, the amount of exhaust gas exhausted from an internal combustion engine increases or decreases according to changes in engine speed.
In particular, when rotating at low speeds, the flow rate of exhaust gas decreases,
Its flow rate also decreases. When the flow velocity of the exhaust gas decreases in this way, there is a problem in that the operating flow velocity for rotationally driving the turbine wheel 2 decreases, making it impossible to increase the supercharging obtained from the compressor to a predetermined pressure.

Further, conventionally, a turbo supercharger is known that utilizes pulsation of exhaust gas to increase the rotational speed of the turbine wheel 2 during low-speed rotation. As shown in Figure 2,
Inside the turbine casing 1, a partition wall 5 is provided which extends from the exhaust gas introduction passage 4 to the scroll part 3 and divides the scroll part 3 into two along the flow direction of the exhaust gas, and is integrally molded with the turbine housing 6. In this divided turbine casing 1, exhaust gas exhausted from each cylinder 7 of the internal combustion engine E is collected and connected to two separate exhaust pipes 9 so that the pulsations do not interfere with each other. be done.

With this configuration, the rotational speed of the turbine wheel 2 can be increased by improving the energy transfer efficiency to the turbine wheel 2 by utilizing the pulsation of the exhaust gas.

However, in such conventional examples,
Since the partition 5 is a fixed wall, the rotation speed of the turbine wheel 2 in the low speed range of the internal combustion engine E is increased, and the rotation speed in the high speed range is also increased. Overcharging and over-rotation of the turbine wheel 2 will cause damage. For this reason, in this type of turbocharger, it becomes necessary to sacrifice its high speed range to some extent, and the internal combustion engine loses its vigor in the high speed range.

In general, the disadvantages mentioned above are that the rotational speed band of the internal combustion engine (effective rotational speed band) in which the turbocharger can supply a predetermined boost pressure and the rotational speed band of the internal combustion engine that is actually regularly used (effective rotational speed band) This is caused by the fact that the actual rotational speed band is narrower than the practical rotational speed band.

The purpose of the present invention is to take into account the problems of conventional turbochargers and to improve them as much as possible. The purpose of this invention is to create a partition plate that moves within the scroll section to control exhaust pulsation, and a shape memory alloy that automatically operates the partition plate in response to the exhaust gas temperature, which changes in response to increases and decreases in the exhaust gas flow rate. An object of the present invention is to provide a turbo supercharger that is equipped with a partition plate actuating means to improve supercharging pressure during low-speed rotation when the exhaust gas flow rate is reduced, thereby improving low-speed torque and fuel efficiency of an internal combustion engine. .

In addition, the purpose of the present invention is to be able to expand the effective rotational speed range of the internal combustion engine in which the effects of the turbocharger are exerted, and to improve the performance of the internal combustion engine in the low speed range without degrading the performance in the high speed range. Our goal is to provide a turbocharger that can.

[Means for Solving the Problems] This invention provides a structure in which a scroll portion of the turbine housing for guiding exhaust gas that drives the turbine wheel is provided near the peripheral edge of the turbine wheel in the low speed rotation range of the engine. , dividing the scroll member into two exhaust gas passages along the scroll direction and arranging a divided movable partition plate that narrows the exhaust gas outlet to the turbine wheel; It engages with the turbine wheel so as to be relatively movable along the radial direction of the turbine wheel and to prevent mutual movement of the turbine wheel in the axial direction so as to form the same plane. One end of a support member that is movable in the direction is connected to the upper part of each movable partition plate, and the other end of the support member senses the temperature inside the scroll section by the wall temperature of the turbine housing, and the temperature of the exhaust gas that has been sensed is transferred to the engine. When in the high speed rotation range, through these supporting members,
The movable partition plates are spaced apart from the peripheral edge of the turbine wheel, and when the detected exhaust temperature is in the low speed rotation range of the engine, the movable partition plates are separated from the peripheral edge of the turbine wheel via the support member. This problem is solved by energizing the partition plate actuating means made of a shape memory alloy and brought close to the peripheral edge.

[Operation] The exhaust gas supplied into the scroll portion gives energy of the exhaust gas to the turbine wheel to drive the turbine wheel. The partition plate operating means made of a shape memory alloy senses and detects the temperature of the exhaust gas, and when the temperature is in the low speed rotation range of the engine, moves each movable partition plate to the peripheral edge of the turbine wheel via the support member. By making the scroll portion close to each other, the scroll portion is partitioned into two exhaust gas passage chambers, and the exhaust gas jet port that finally causes the exhaust gas to collide with the turbine wheel is narrowed down. As a result, the flow velocity of the exhaust gas is increased, so that the turbine wheel is optimally driven even in this low-speed rotation range.

Further, the partition actuating means separates each movable partition plate from the peripheral edge of the turbine wheel via the support member when the temperature of the exhaust gas sensed and detected is in a high speed rotation range of the engine. Then, the exhaust gas outlet that causes the exhaust gas to collide with the turbine wheel is widened in the low-speed rotation range, so the flow velocity of the exhaust gas against the turbine wheel becomes appropriate for this high-speed rotation range, and over-rotation of the turbine wheel is prevented. be done.

By the way, since the movable partition plates are engaged with each other so as to form the same plane along the scroll direction, the flow of exhaust gas within the scroll section is not obstructed, and each movable partition plate is supported by a support member. The dividing surfaces adjacent to each other on the movable partition plates are engaged with each other so as to be allowed to move relative to each other in the radial direction of the turbine wheel, and are prevented from moving relative to each other in the axial direction of the turbine wheel. Therefore, even if pressure fluctuations or large exhaust pulsations of exhaust gas passing through the scroll portion are applied to each movable partition plate, these pressure fluctuations and exhaust pulsations are received by the movable partition plates as a whole. In other words, the movable partition plates have such rigidity that they can be fixed at predetermined positions even in different rotation ranges. In other words, the structural strength of the movable partition plate is significantly increased. This improves the operation of the partition plate control means, and also improves and maintains the function and durability of the movable partition plate in a turbocharger that varies the flow rate of exhaust gas. Its reliability can be significantly improved.

[Embodiments] Next, preferred embodiments of the present invention will be described in detail based on the accompanying drawings.

As shown in FIGS. 3 and 4, a turbine housing 11 is provided to surround the turbine wheel 2 so that the turbine wheel 2 is rotationally driven by exhaust gas exhausted from the internal combustion engine E. Turbine housing 11
The scroll part 12 surrounds the turbine impeller 2 and the exhaust gas introduction passage part 13 for introducing exhaust gas into the scroll part 12 defines a turbine casing 14. Further, an exhaust gas supply port 15 is formed in the scroll portion 13 of the turbine casing 14 so as to face the peripheral edge of the turbine impeller 2 and supply exhaust gas thereto.

Furthermore, a partition plate 16 is provided inside the scroll portion 12 to divide it into two along the circumferential direction, and an exhaust gas passage chamber 18 having an exhaust gas jet port 17 facing the peripheral edge of the turbine impeller 2 is provided. Form a compartment. Further, the partition plate 16 is divided into an appropriate number of parts (in the illustrated example, divided into three parts) so as to be moved outward in the radial direction, and is formed by movable partition plates 19, 19 and a fixed partition plate 20. .

A support member 21 is formed on the movable partition plate 19 from its outer peripheral end, passing through the turbine housing 11 and extending out of the turbine casing 14 . This support member 21 supports the movable partition plate 19, and detects the wall temperature of the turbine housing 1 to automatically adjust the exhaust gas temperature, which changes depending on the exhaust gas flow rate, without being affected by the heat and pressure fluctuations of the exhaust gas. It is connected to a partition plate operating means 22 for reciprocating the partition plate 19 in the radial direction.

The partition plate operating means 22 includes the support member 21 and
A disk-shaped flange portion 23 formed at its tip
and the flange portion 23 surrounding these and the flange portion 23
A cylindrical hollow chamber 24 allows for reciprocating movement.
and two types of springs A fitted between the casing top cover 26 and the flange portion 23 within the hollow chamber 24.

The above springs A and B include the normal spring A, which has a spring constant K _A that is approximately constant with respect to temperature changes, and the spring constant K _B , which changes at the set temperature T _O , where T > T _O. When K _B > K _A , when T < T _O , K _B
<K _A shape memory alloy spring B is used.

When these springs A and B are inside the hollow chamber 24, the spring A biases the flange portion 23 inward in the radial direction, and the spring B is fixed by the fixing claw 27 and is attached to the casing upper lid 26. It is configured to connect the flange portion 23 and urge it to be pulled back radially outward.

Therefore, when T<T _O , since K _B <K _A, the spring A overcomes the contraction force of the spring B and expands, pushing out the flange portion 23 and bringing the partition plate 19 closer to the turbine wheel 2 . Also, when T > T _O , since K _B > K _A , spring B overcomes the extension force of spring A and contracts, pulling back the flange portion 23 and moving the partition plate 19 towards the turbine wheel 2.
Separate from.

By the way, in order to provide the partition plate 16 in the turbine casing 14 including the casing part 27 of the partition plate actuating means 22, the turbine housing 11 has divided pieces 28, which are divided from approximately the center along the longitudinal direction. 29. These divided pieces 2
A flange 30 is formed on the peripheral edge of each 8, 29, and this flange 30 is fastened with bolts 31 and nuts 32, and the turbine housing 11 is integrally formed to partition the turbine casing 14. Become.

On the other hand, a movable partition plate 19 is provided at the flange 30 portion.
A housing groove 33 for the partition plate 19 is formed along the outer peripheral edge of the partition plate 19 to allow movement of the partition plate 19 in the radial direction.

Further, the fixed partition plate 20 extends into the exhaust gas introduction passage section 13 and divides it into two parts, thereby forming an exhaust gas passage chamber 18 formed within the scroll section 12.
It forms an exhaust gas introduction passage chamber 34 that is continuous with the flange portion 30, and is clamped by the flange portion 30 and fixedly supported by being tightened together with bolts and nuts.

Furthermore, the partition plate 16 has movable partition plates 19,1
9 and between the movable partition plate 19 and the fixed partition plate 20, as shown in FIG.
The engagement protrusion 37 engaged with the engagement groove 36 enables relative movement in the radial direction with respect to the turbine wheel 2 and prevents mutual movement in the axial direction with respect to the turbine wheel 2. Partition plates 16 that are connected and form a continuous same plane along the scroll direction.
form.

Therefore, as shown in FIGS. 3 and 4, the turbine casing 14 is connected to the inlet 48 of the exhaust gas introduction passage chamber 44.
From there to the exhaust gas outlet 17 of the exhaust gas passage chamber 18, there are two continuous exhaust gas passages that are divided along the flow direction of the exhaust gas.

Further, the exhaust gas exhausted from the internal combustion engine E is divided and collected into two exhaust pipes 38 to utilize its pulsation. The exhaust gases collected in the respective exhaust pipes 38 are collected in different ignition orders so that the exhaust gases exhausted from the cylinders 39 of the internal combustion engine E do not interfere with each other in their pulsations. For example, in the illustrated six-cylinder internal combustion engine E, #1→
In the case of the ignition order of #5 → #6 → #2 → #4,
The #1, #2, and #3 cylinders and the #4, #5, and #6 cylinders are each grouped together and divided into two exhaust pipes 38.

Therefore, the exhaust gas collected in this way is introduced into the turbine casing 14, passes through two separated exhaust gas passages, and retains its pulsation.
The exhaust gas is ejected from the exhaust gas outlet 17 to the turbine wheel 2 .

Next, the operation of this embodiment will be explained.

As shown in FIGS. 3 and 4, the engine speed of the internal combustion engine E shifts from high-speed operation to low-speed operation,
When the exhaust gas flow rate decreases and its temperature falls below the set temperature, or when the engine speed is low and the exhaust gas temperature falls below the set temperature, such as when starting, the partition plate actuating means 22 operates. It functions to bring the movable partition plate 19 closer to the turbine wheel 2.

That is, when the temperature of the exhaust gas flowing through the scroll portion 12 decreases, the temperature of the turbine housing 11 also decreases accordingly. At this time, the partition plate operating means 2 is integrally molded with the turbine housing 11.
When the temperature of the second part falls below the set temperature T _O , the spring B becomes T<T _O , and the spring constant K _B becomes the spring A.
is smaller than the spring constant K _A of , and K _B <K _A. Then, the spring A expands against the contraction force of the spring B, the flange portion 23 is pushed out, the movable partition plate 19 is moved radially inward, and the turbine wheel 2
It will be placed close to.

By bringing the movable partition plate 19 close to the turbine wheel 2, the inside of the scroll portion 12 is completely divided into two parts, and exhaust gas is directly supplied to the turbine wheel 2 from the exhaust gas outlet 17 of the exhaust gas passage chamber 18.

Therefore, the exhaust gas flowing through the two exhaust gas passage chambers 18 is split and ejected from the respective exhaust gas jet ports 17, and the pulsations of the exhaust gas are not interfered with and have pulse-like high energy, and are sent to the turbine wheel 2. Supplied. As a result, the energy transmission efficiency to the turbine wheel 2 is improved, the rotational speed of the turbine wheel 2 is increased, and the supercharging pressure in the low speed rotation region is increased.

Here, at this time, the respective movable partition plates 19, 19 and the divided connection parts of the movable partition plate 19 and the fixed partition plate 20 are mutually prevented from moving in the axial direction of the turbine impeller 2, and , is supported by the support member 21, so even when atmospheric pressure fluctuations or pressure waves due to exhaust pulsation act within the scroll portion 12, each movable partition plate 19 and the support member 21 absorb the force. Because it receives the whole, each moving partition plate 1
9 position can be maintained.

Furthermore, when the internal combustion engine E shifts from low-speed operation to high-speed operation and the engine speed increases, the exhaust gas flow rate increases and its temperature also rises. Therefore,
As the exhaust gas temperature rises, the turbine housing 1
When the temperature of the partition plate actuating means 22 exceeds the set temperature T _O , the spring constant K _B of the spring B is larger than the spring constant K _A of the spring A because T > T _{O. B} > K _A. Therefore, the spring B contracts against the extension force of the spring A, and the flange portion 23 is pulled back, and the movable partition plate 19 is moved radially outward and separated from the turbine wheel 2.

As shown in FIG. 6, when the movable partition plate 19 is separated from the turbine wheel 2, the exhaust gas outlet 17 of the exhaust gas passage chamber 18 is also separated, and the exhaust gas flows ejected from the two exhaust gas outlets 17 are mixed. The exhaust gas is then ejected to the turbine wheel 2 from the exhaust gas supply port 15 formed by the scroll portion 12 . Even at this time, each movable partition plate 19 and fixed partition plate 2
0 and the movable partition plate 19 are mutually maintained and further supported by the support member 21, so that the flow of exhaust gas within the scroll portion 12 is not disturbed. This allows the partition plate operating means 22 to function reliably.

Therefore, the pulsations of the exhaust gas interfere with each other, are attenuated and cancelled, and act on the turbine wheel 2 as a steady flow having substantially constant energy. Therefore, the efficiency of energy transmission to the turbine wheel 2 is reduced, and the turbine wheel 2 is prevented from being over-rotated beyond a predetermined set rotation speed range.

Therefore, when the exhaust temperature of the internal combustion engine E is lower than the set temperature, that is, when the engine is operated at low speed and the engine speed is low, the boost pressure is increased and low-speed torque and fuel efficiency are achieved. can be improved. On the other hand, in the high-speed rotation range where the exhaust temperature is high, the predetermined boost pressure is maintained, the performance of the internal combustion engine E in the high-speed range is maintained, and damage to the turbine wheel 2 due to over-rotation is prevented. be done.

In this embodiment, one movable partition plate is provided with two partition plate operating means, but not only one or more may be provided, but the number of divisions of the movable partition plate may also be changed according to the present embodiment. Not limited.

[Effects of the invention] As described above, the present invention provides the following excellent effects.

Movable partition plates divided along the scroll direction are mutually movable in the radial direction of the turbine wheel, and mutually prevent movement of the turbine wheel in the axial direction, and furthermore, these movable partition plates are divided along the scroll direction. Since it is supported by a support member that passes through the scroll section so as to be movable in the radial direction, it is possible to ensure sufficient rigidity over a long period of time against pressure fluctuations and exhaust pulsations that occur within the scroll section.

The reliability of the partition plate operating means can be greatly improved.

The boost pressure in the low-speed rotation region of the internal combustion engine can be increased, the low-speed torque thereof can be improved, and the fuel efficiency can be improved as much as possible.

The turbine wheel is not over-rotated in the high-speed rotation region of the internal combustion engine, and the turbine wheel is not damaged.

Compared to a conventional internal combustion engine with a turbo supercharger, the effective rotation speed range in which the turbo supercharger is effective can be expanded across its low speed and high speed rotation regions, and the internal combustion engine It can be adapted as much as possible to the commonly used practical rotational speed range.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing a turbine casing of a conventional turbocharger, Fig. 2 is a side cross-sectional view showing a turbine casing of a conventional turbocharger having a partition wall in the turbine casing, Fig. 3 is a partially cutaway front view showing one embodiment of the present invention, Fig. 4 is a side cross-sectional view of Fig. 3, Fig. 5 is a cross-sectional view taken along line V-V in Fig. 3, and Fig. 6 is a cross-sectional view taken along line V in Fig. 3. In the drawings, 2 is a turbine impeller, 11 is a turbine housing, 12 is a scroll portion, 14 is a turbine casing, 16 is a partition plate, 17 is an exhaust gas outlet, 18 is an exhaust gas passage chamber, 22 and 42 are partition plate operating means, B
is a shape memory alloy spring, and E is an internal combustion engine.

Claims (1)

[Scope of utility model registration request] Within the scroll portion of the turbine housing for guiding exhaust gas that drives the turbine wheel, two exhaust gas passages are provided in the low speed rotation range of the engine, close to the peripheral edge of the turbine wheel, and running inside the scroll portion along the scroll direction. A divided movable partition plate is arranged to narrow the exhaust gas outlet to the turbine wheel, and the adjacent dividing surfaces of each movable partition plate are movable relative to each other along the radial direction of the turbine wheel. The movable partitions are connected to one end of a support member which is engaged so as to prevent mutual movement of the turbine impellers in the axial direction and form the same plane, and which passes through the scroll portion and is movable in the radial direction of the turbine impellers. Connected to the upper part of the plate, the other end of the support member senses the temperature inside the scroll section by the wall temperature of the turbine housing, and when the sensed exhaust gas temperature is in the high speed rotation range of the engine, the support member The movable partition plates are spaced apart from the peripheral edge of the turbine wheel, and when the detected exhaust temperature is in the low speed rotation range of the engine, the movable partition plates are separated from the peripheral edge of the turbine wheel via the support member. A turbo supercharger characterized in that a partition plate operating means made of a shape memory alloy is biased and provided close to the peripheral edge.