JPH041311Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an engine turbocharging device.

[Prior Art] Engines for automobiles and other vehicles are operated over an extremely wide range of rotation speeds, from idle speed to maximum speed, and within a load range that fluctuates widely, so the amount of exhaust gas is also significantly reduced. It fluctuates. Therefore, an exhaust gas turbine having a single flow rate characteristic cannot sufficiently recover and utilize the exhaust gas energy discharged from the engine. Therefore, a partition wall is provided in the turbine housing to divide the exhaust gas introduction path in the same housing into two or more exhaust gas introduction paths with different flow characteristics, and
A valve device is provided in one or more of the divided exhaust gas introduction passages, and the valve device is opened and closed according to operating conditions such as engine speed and load, thereby improving the operating efficiency of the exhaust gas turbine. Variable displacement turbochargers have already been proposed.

The exhaust gas turbine in this type of variable capacity turbocharger is equipped with a valve device that opens and closes the two or more divided exhaust gas introduction passages.

On the other hand, it has been conventional practice to provide an exhaust brake valve on the exhaust side of the engine and obtain a braking effect on the vehicle by the exhaust pressure when the valve is closed.

[Problem that the invention attempts to solve]

By the way, in such conventional exhaust brake valves, in order to prevent adverse effects on the valve train system, a small hole is drilled in the exhaust brake valve so that the exhaust pressure does not rise above the required pressure even when the exhaust brake valve is closed. ing.

For this reason, when the engine is running at low speeds, even though the exhaust pressure has not reached the level required to obtain a sufficient exhaust braking effect, the exhaust gas leaks from the small hole mentioned above, and the exhaust pressure decreases to obtain a sufficient exhaust braking effect. There was a problem that I couldn't do it.

The present invention attempts to solve these problems by making it possible to obtain a sufficient exhaust braking effect over the entire engine speed range, and also to provide supercharging according to the engine operating conditions during normal operation. An object of the present invention is to provide a variable capacity turbocharger that can perform the following steps.

[Means for solving problems]

Therefore, the variable capacity turbocharging device of the present invention includes a turbine housing in which a plurality of exhaust inlets are formed, a plurality of downstream openings that communicate with the plurality of exhaust inlets, and an upstream opening that communicates with the exhaust manifold of the engine. a hollow valve casing having an opening formed therein; a partition wall that partitions at least a portion of the inside of the valve casing into a plurality of exhaust gas introduction passages communicating with the plurality of downstream openings; and an upstream end of the plurality of exhaust gas introduction passages. In a variable capacity turbocharger including a plurality of valve devices respectively arranged, each of the plurality of valve devices has a valve seat formed at an upstream end of the exhaust gas introduction passage and a valve on the same valve seat. A valve member that opens and closes the opening and forms a side wall of the exhaust gas introduction passage facing the partition wall when the valve member is in the fully open position, and an inside of the valve casing that is separated from the exhaust gas introduction passage by the valve member when the valve member is in the fully open position. The present invention is characterized in that it is comprised of a support shaft disposed in a space, and a swing arm whose one end is swingably supported by the support shaft and whose other end is connected to the valve member.

[Effect]

With the above configuration, during normal operation, parts of the two or more inlets are opened and closed by the valve device, and a gentle exhaust gas passage is formed both in the open state and the closed state of the valve device.

Furthermore, it becomes easy to manufacture the valve member to match the opening shape of the valve seat, and as a result, the sealing performance of the valve device when fully closed is improved, and the braking effect when the exhaust brake is activated is improved.

Furthermore, since the valve member and the support shaft are not located within the exhaust gas introduction path even when the valve is fully open, exhaust resistance does not increase in operating conditions where there is no need to operate the exhaust brake.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Figs. 1 to 4 show a variable capacity turbocharger as an embodiment of the invention, and Fig. 1 is a schematic diagram showing the overall configuration; 2 to 4 are graphs showing the characteristics, respectively.

As shown in FIG. 1, in the turbocharger 10,
Exhaust gas turbine 12 and exhaust gas turbine 1
A compressor 14 is provided which is driven by 2. The exhaust gas turbine 12 includes a turbine housing 18 that accommodates a turbine rotor 16. Inside the turbine housing 18, there are flow rate characteristics divided in the rotor axial direction by partition walls 20 extending in the radial direction. Different exhaust gas introduction passages, namely scrolls A and B, are provided.

Further, a valve casing 24, which will be described in detail later, is connected to the exhaust gas inlet 22 of the turbine housing 18, and the valve casing 24 is further connected to an engine exhaust system (not shown), that is, an exhaust manifold 26 in this embodiment. .

Note that the exhaust gas inlet 22 is provided with the partition wall 2.
Inlets 22a, 22 are separated by an extended portion of 0 and are continuous to the exhaust gas introduction paths A, B, respectively.
b is provided.

Next, the valve casing 24 has an approximately box-shaped outer shape, and an upstream opening 28 communicating with the exhaust manifold 26 is provided on the upper wall surface in the drawing, and inlets 22a and 22b are provided on the lower wall surface, respectively. Connecting downstream openings 30a, 30b are provided.

Moreover, the upstream opening 28 and the downstream openings 30a, 30b
A valve seat 32a, which has a seat surface in two planes intersecting in a V-shape at a 90 degree angle, is provided between the valve seat 32a and
32b are provided, and the valve openings of these valve seats are opened and closed by valve members 34a and 34b, respectively.

The valve members 34a, 34b have protruding shafts 36a, 36b on their back surfaces, respectively.
36b is supported by the free ends of the swinging arms 38a, 38b with sufficient play in the radial direction, and the other end of each swinging arm 38a, 38b is connected to the relatively upstream side wall of the valve casing 24. It is fixed to support shafts 40a and 40b pivotally supported above. The valve casing 24 has openings on the left and right sides in the figure for attachment, removal, inspection, etc. of the valve members 34a and 34b, and normally these openings are provided with a removable lid 42. It has since been closed.

In this embodiment, the valve member 34 is supported on the free end of the swinging arm 38a by a spherical seat, but it does not necessarily have to be a spherical seat, and may be supported by a flat seat. In this case, it is desirable to provide an appropriate clearance between the two in the axial direction of the protruding shaft 36a.

The cross-sectional shape of the upstream opening 28, the valve opening of the valve seat 32a, and the exhaust gas introduction passage from the valve opening to the downstream inlets 22a and 22b may be any of a rectangle with rounded corners, an oval, an ellipse, and a circle. Alternatively, a combination of these may be used. Further, it is desirable that the shape of the valve member 34 is approximately similar to the shape of the valve opening of the valve seat 32a.

A valve control mechanism C is attached to the swing arm 38a.

The valve control mechanism C is composed of an actuator 50 and a fluid pressure source 51, and a required air pressure is supplied from the fluid pressure source 51 to control the actuator 5.
A pressing force obtained by subtracting the return spring force of the return spring 50a within 0 is applied to the swing arm 38a.

As a result, in the closed state of the valve members 34a and 34b, if the exhaust pressure of the exhaust manifold 26 on the upstream side exceeds the required pressure (pressure corresponding to the above-mentioned pressing force), the valve member 34a is moved to the actuator 50. It is designed to open against the air pressure inside.

Since the variable capacity turbocharger as an embodiment of the present invention is configured as described above, it is possible to operate the engine at low speed and high load (region _B1 in Fig. 3).
, valve member 34a is closed and valve member 34b is closed.
is opened to allow exhaust gases from the exhaust manifold 26 to pass through the upstream opening 28, the valve opening in the valve seat 32b, the corresponding downstream opening 30b, and the inlet 2 of the turbine housing.
2b acts on the blades of the turbine rotor 16 through the exhaust gas introduction path B, and efficiently operates the exhaust gas turbine 12 with the flow rate characteristic shown by B ₁ in FIG. In this state, the valve member 34b is open.
cooperates with the partition wall 44 to form a generally gently curved exhaust gas introduction path with low resistance in the valve casing 24 on the downstream side from the valve seat 32b. The valve member 34a seated on the valve seat 32a included in planes that intersect at an angle constitutes a part of the introduction passage wall on the upstream side of the valve seat 32b, so that the exhaust gas is introduced smoothly and with little resistance. form a road.

In addition, the engine is in a medium speed and high load state (see Figure 3).
When operating in _B2 area), the valve member 34a
is opened and the valve member 34b is closed, and in exactly the same manner as described above, the exhaust gas introduction path A having large flow rate characteristics is opened.
Exhaust gas is supplied to the turbine rotor 16 from. That is, it is operated with flow rate characteristic _B2 .

In this case as well, as shown, the valve casing 2
Since the valve seat and the exhaust gas introduction path are formed almost symmetrically on both sides of the partition wall 44 in the exhaust gas chamber 4, a gentle introduction path with low flow resistance is formed, just like the above.

Furthermore, during high-speed, high-load and low-load operation of the engine (area _B3 in FIG. 3), the two valve members 34a and 34 are
b are both opened, and the exhaust gas flowing into the valve casing 24 from the upstream opening 28 flows through the central partition wall 44.
The exhaust gas flows into the turbine housing inlets 22a and 22b from the downstream openings 30a and 30b, respectively, through the introduction passage divided into left and right parts by the exhaust gas introduction passages A and B, and flows into the turbine rotor 16 from both the exhaust gas introduction passages A and B according to the flow rate characteristic _B3. Supplied.

In this case as well, the opened valve members 34a and 34b cooperate with the partition wall 44 to serve as one side wall of the exhaust gas introduction path.

As mentioned above, by arranging the valve seat and valve member in a special manner between the exhaust gas turbine of the turbocharger and the engine exhaust system, such as the exhaust manifold, the valve seat and valve member can be arranged in a special manner depending on the operating state of the engine. The exhaust gas can be supplied to the exhaust gas turbine via a suitable and selected introduction path with low flow resistance.

On the other hand, when operating the exhaust brake on the engine, the valve members 34a and 34b are closed.

As a result, the exhaust manifold 26 is brought into a closed state, and the exhaust pressure Pe within the exhaust manifold 26 provides an exhaust braking effect.

In this case, the valve device is configured with a valve member that opens and closes the opening of the valve seat newly formed at the upstream end of the exhaust passage and a swinging arm that swings and supports the valve member as separate bodies. It becomes easy to create the valve member to match the opening shape of the valve seat, and therefore,
The sealing performance of the valve device when fully closed is improved, and the braking effect when the exhaust brake is activated is improved. In addition, since the support shaft is disposed in a space separated from the exhaust gas introduction passage by the valve member when the valve member is in the fully open position, the valve member and the support shaft remain within the exhaust gas introduction passage even when the valve is fully open. There is no risk of the boost pressure decreasing even when the engine speed is low and the exhaust gas flow rate is low.

And, this exhaust braking effect reduces the exhaust pressure when the engine is operated in a low rotation range.
Since Pe does not reach the required pressure Peo that has a negative effect on the valve train, the valve member 34a does not open against the air pressure inside the actuator 50.
The exhaust pressure Pe is completely sealed, and the braking effect of the highest exhaust pressure Pe at that rotational speed is obtained.

Further, when the engine is operated in a medium to high speed range, if the exhaust pressure Pe becomes equal to or higher than the required pressure Peo as a result of the closing operation of the valve members 34a and 34b, the valve member 34a It is opened against air pressure.

Thereafter, the valve member 34a is opened to a position where the pressing force by the actuator 50 and the exhaust pressure Pe are balanced.
The exhaust pressure Pe in the exhaust manifold 26 is maintained at pressure Peo.

That is, as shown by the dotted line in Fig. 2, conventionally, the exhaust pressure Pe at which the exhaust braking effect can be obtained changes according to the engine rotation speed, and it is difficult to obtain the required pressure Peo when the engine rotation speed is high. Because a small hole was drilled in the exhaust brake to allow the engine to run smoothly, the exhaust pressure Pe dropped significantly when the engine speed was low.

However, according to the device of this embodiment, when the exhaust pressure Pe in the exhaust manifold 26 is below the required pressure Peo, the closed state is maintained, and when the exhaust pressure Pe exceeds the required pressure Peo, Pe is The opening degree of the valve member 34a is automatically adjusted so that the required pressure is maintained regardless of the engine speed.
With Peo as the limit, the highest exhaust pressure Pe at that engine speed acts as the exhaust pressure Pe of the exhaust brake.

In other words, a sufficient exhaust braking effect can be obtained over the entire engine speed range.

Note that the force acting on the valve member 34a is determined by the air pressure in the return spring 50a being Pa, the pressure receiving area of the actuator 50 being Aa, and the force acting on the actuator 50.
If the return spring force is Fs, and the pressure receiving area of the valve member 34a is Av, then (PaAa−Fs),
Pa, Aa, and Fs are set to satisfy PaAa−Fs=AvPeo.

That is, when Pe>Peo, PaAa-Fs=AvPeo<AvPe, the valve member 34a is pushed open, and its opening degree is automatically adjusted so that PaAa-Fs=AvPeo=AvPe.

In this way, the turbocharger 10 allows
Not only is efficient supercharging performed, but the exhaust braking effect can also be properly achieved.
Note that if this device is used, a conventional exhaust brake is not required, and costs can be reduced accordingly.

The valve seat 32 is most preferably arranged in a plane (not necessarily a plane) that intersects the vertical plane at an angle of 45 degrees, but the angle is approximately 30 degrees to 60 degrees. It is possible to make a wide range of changes, and generally the same effect can be obtained.

Further, as an application example of the present invention, a third exhaust gas introduction path can be provided in the exhaust gas turbine housing in addition to the introduction paths A and B in the embodiment,
It can also be configured to be opened and closed by a third valve separate from the valve members 34, 34 described above.

[Effect of idea]

As described in detail above, the variable capacity turbocharging device of the present invention includes a turbine housing in which a plurality of exhaust inlets are formed, a plurality of downstream openings each communicating with the plurality of exhaust inlets, and an engine. a hollow valve casing formed with an upstream opening communicating with an exhaust manifold; a partition wall partitioning at least a portion of the inside of the valve casing into a plurality of exhaust gas introduction passages communicating with the plurality of downstream openings; and a plurality of exhaust gases. In a variable capacity turbocharger including a plurality of valve devices each disposed at an upstream end of an introduction path, each of the plurality of valve devices has a valve seat formed at an upstream end of the exhaust gas introduction path. a valve member that opens and closes the valve opening of the valve seat and forms a side wall of the exhaust gas introduction passage facing the partition wall when the valve member is in the fully open position; a support shaft disposed in a space within the valve casing separated from each other;
The following effects and advantages can be obtained with a simple structure consisting of a swing arm whose one end is swingably supported by the support bearing and whose other end is connected to the valve member.

(1) The valve device is configured with a valve member that opens and closes the opening of the valve seat newly formed at the upstream end of the exhaust passage and a swinging arm that swings and supports the valve member as separate parts. It becomes easy to create the member to match the opening shape of the valve seat, thus improving the sealing performance of the valve device when fully closed, and improving the braking effect when the exhaust brake is activated.

(2) Since the support shaft is arranged in the space separated from the exhaust gas introduction passage by the valve member when the valve member is in the fully open position, the valve member and the support shaft are located within the exhaust gas introduction passage even when the valve is fully open. There is no fear that the boost pressure will decrease even when the engine speed is low and the exhaust gas flow rate is low.

(3) Since the support shaft is arranged in the space separated from the exhaust gas introduction passage by the valve member when the valve member is in the fully open position, the valve member and the support shaft are located within the exhaust gas introduction passage even when the valve is fully open. Therefore, the exhaust resistance does not increase unnecessarily in operating conditions where the exhaust brake does not need to be operated.

[Brief explanation of the drawing]

Figures 1 to 4 show a variable displacement turbocharger as an embodiment of the present invention. Figure 1 is a schematic diagram showing its overall configuration, and Figures 2 to 4 are graphs showing the characteristics of each. be. 10... Turbo supercharger, 12... Exhaust gas turbine, 14... Compressor, 16... Turbine rotor, 18... Turbine housing, 20...
...Partition wall, 22...Exhaust gas inlet, 22a, 22b
...Inlet, 24...Valve casing, 26...Exhaust manifold, 28...Upstream opening, 30a, 30b
...Downstream opening, 32a, 32b...Valve seat, 34
a, 34b... Valve member, 36a, 36b... Protruding shaft, 38a, 38b... Swinging arm, 40a, 40b
... Support shaft, 42 ... Lid, 44 ... Partition wall, 50 ...
... Actuator, 50a ... Return spring, 51 ... Fluid pressure source, A, B ... Exhaust gas introduction path, C ... Valve control mechanism, Pe ... Exhaust pressure, Peo ...
Pressure, V...valve device.

Claims (1)

[Scope of utility model registration request] a turbine housing in which a plurality of exhaust inlet ports are formed; a hollow valve casing in which a plurality of downstream openings each communicate with the plurality of exhaust inlet ports; and an upstream opening in communication with an exhaust manifold of an engine; A variable valve device comprising: a partition wall that partitions at least a portion of the inside of the casing into a plurality of exhaust gas introduction passages communicating with the plurality of downstream openings; and a plurality of valve devices respectively disposed at upstream ends of the plurality of exhaust gas introduction passages. In the capacity turbocharging device, each of the plurality of valve devices opens and closes a valve seat formed at an upstream end of the exhaust gas introduction passage, and a valve opening of the valve seat, and faces the partition wall in a fully open position. a valve member forming a side wall of the exhaust gas introduction passage;
a support shaft disposed in a space within the valve casing that is separated from the exhaust gas introduction passage by the valve member when the valve member is in a fully open position; and a swinging arm connected to a valve member,
Variable capacity turbocharger.