JPH0326268Y2 - - Google Patents

Description

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

[Conventional technology]

Engines for vehicles such as automobiles are operated over an extremely wide rotational speed range from idle rotational speed to maximum rotational speed, and within a load range that fluctuates widely, so the amount of exhaust gas also fluctuates significantly. 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 aims to solve these problems by ensuring that sufficient exhaust braking effect is achieved over the entire engine speed range, and also ensuring that exhaust gas flows smoothly into the turbine housing during normal operation. It is an object of the present invention to provide a variable capacity turbo supercharging device which can perform supercharging according to engine operating conditions by sending the supercharger to the engine.

[Means for solving problems]

Therefore, the variable capacity turbocharging device of the present invention includes a turbine housing provided with two exhaust gas introduction passages having different flow characteristics, a valve casing interposed between the turbine housing and the exhaust manifold, and a valve casing interposed between the turbine housing and the exhaust manifold. A partition wall provided in the valve casing and extending from the end of the turbine housing to the middle part on the exhaust manifold side and forming two flow passages each communicating with the exhaust gas introduction passage, and an edge of the partition wall on the middle part side. a valve seat formed to have an opening in each of the two planes that intersect along the two planes, and one of the planes is formed as an exhaust gas passage wall to the other flow passage; and two valves, each of which opens and closes the valve seats and opens downstream in the exhaust gas flow direction via two swing arms each pivotally supported on the valve casing, and which are each formed along the flow path. a valve member; a valve control mechanism that opens and closes the two valve members; an exhaust pressure sensor that detects the exhaust pressure in the exhaust manifold; and a controller that outputs output to the valve control mechanism, and the controller sends a signal to the valve control mechanism to open either one of the two valve members when the exhaust pressure is detected to be higher than a predetermined pressure when the exhaust brake is activated. It is characterized by transmitting a signal to the valve control mechanism to detect the open and closed states of the two valve members and to close the valve member that is in the open state when the above-mentioned predetermined pressure or lower is detected. .

[Effect]

With the above configuration, during normal operation, part of the two or more inlets are opened and closed by the valve device, and a gentle exhaust gas passage is formed even when the valve device is in the open state and in the closed state. When operating the exhaust brake,
The closed state is maintained until the exhaust pressure on the upstream side of the valve device exceeds the required pressure, and when the pressure exceeds the required pressure, which has an adverse effect on other valve systems, the valve device is opened and the upstream side of the valve device is opened. side is maintained at a maximum pressure below the required pressure.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Figs. 1 to 5 show a variable capacity turbocharger as an embodiment of the invention, and Fig. 1 is a schematic diagram showing its overall configuration; FIG. 2 is a flowchart showing the operation, and FIGS. 3 to 5 are graphs showing the respective characteristics.

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;
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. Furthermore, 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 includes an actuator 50 and a fluid pressure source 51 that supplies operating pressure to the actuator 50.
It is composed of.

The actuator 50 also includes a valve control mechanism C.
A controller 52 is provided which is connected to an exhaust pressure sensor 53 installed in the exhaust manifold 26 for feedback control.

Note that the swing arm 38b is also provided with a valve control mechanism (not shown) composed of an actuator and a fluid pressure source, similar to the above-mentioned valve control mechanism C.
A controller 52 is attached to it.

The controller 52 is configured to perform the operations shown in the flow chart shown in FIG.

That is, the actuator 50 is actuated based on the opening/closing signal of the valve device outputted from the controller 52, the swinging arm 38a is driven, the valve member 34a is opened and closed, and the exhaust manifold 26 on the upstream side of the valve member 34a is opened and closed. The internal pressure is maintained at the maximum pressure below the required pressure Peo.

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. 4).
, valve member 34a is closed and valve member 34b is closed.
is opened to allow exhaust gas 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 passes through the exhaust gas introduction path B and acts on the blades of the turbine rotor 16, and the exhaust gas turbine 12 is operated efficiently due to the flow rate characteristics shown by _B1 in FIG. In this state, the open valve member 34b cooperates with the partition wall 44 to form a generally gently curved exhaust gas introduction path with low resistance within the valve casing 24 on the downstream side from the valve seat 32b;
The valve member 34a seated on the valve seat 32a, which is included in a plane that intersects the plane containing the valve seat 32b at an angle of approximately 90 degrees, is a part of the introduction passage wall upstream from the valve seat 32b. to form a gentle exhaust introduction path with low resistance.

Also, the engine is in a high speed, high load state (see Figure 4).
When operating in _B2 area), the valve member 34a
is opened and closed by the valve member 34b, and in exactly the same manner as described above, the exhaust gas introduction path A has a large flow rate characteristic.
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 in exactly the same manner as described above.

Furthermore, when the engine is operating at low load (see Figure 4),
In region _B3 ), the two valve members 34a and 34b are both opened regardless of the rotation speed, and the exhaust gas flowing into the valve casing 24 from the upstream opening 28 is blocked by the central partition wall 44. The downstream openings 30a, 30 pass through the introduction path divided into left and right sides.
b respectively to the inlet 22 of the turbine housing.
a, 22b, and is supplied to the turbine rotor 16 from both exhaust gas introduction paths A and B according to the flow rate characteristic _B3 .

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 exhaust brake switch (not shown) is turned on as shown in step S1 in FIG.

As a result, step S2 is executed in the controller 52, and the actuator 50 is driven so that the valve members 34a and 34b are fully closed. In this embodiment, the valve member 34b is maintained in a fully closed state when the exhaust brake is activated.

Next, step S3 is executed, and the exhaust pressure Pe in the exhaust manifold 26 is detected by the exhaust pressure sensor 53 and transmitted to the controller 52.

In the controller 52, the exhaust pressure Pe is
It is determined whether the pressure is below the required pressure Peo set in advance in the controller 52,
If yes, step S5 is executed.

In step S5, it is determined whether the valve member 34a is closed, and if YES, the state is maintained.

If the answer is NO, the actuator 50 is operated to close the valve member 34a, and then steps S3 to S6 are repeated.

On the other hand, if it is determined in step S4 that the exhaust pressure Pe of the exhaust manifold 26 is greater than the pressure Peo, the no route is taken, step S7 is executed, and the actuator 50 is actuated to open the valve member 34a. Activation is performed.

In this way, steps S4, S7, and S3 are repeated until the exhaust pressure Pe becomes less than or equal to the pressure Peo.
is repeated, and the opening degree of the valve member 34a is adjusted so that the exhaust pressure Pe becomes equal to or less than the pressure Peo.

In this way, the following exhaust braking effect can be obtained.

That is, when the engine is operated in a low rotation range, the exhaust pressure Pe does not reach the required pressure that adversely affects the valve train, so the valve member 34a opens against the air pressure in the actuator 50. The exhaust pressure Pe is completely sealed without any
A braking effect can be obtained by the highest exhaust pressure Pe at that rotation speed.

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 Based on the signal, the actuator 50 is opened against the air pressure inside it.

Then, by feedback control from step S3 to step S7, the actuator 50
The valve member 34a is opened at a position where the pressing force and the exhaust pressure Pe are balanced, and the exhaust pressure Pe in the exhaust manifold 26 is maintained at the pressure Peo.

That is, as shown by the dotted line in Fig. 3, 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 also drilled in the exhaust brake to ensure this, the exhaust pressure Pe significantly decreased 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 Since the opening degree of the valve member 34a is automatically adjusted via the controller 52 as shown in FIG. Acts as atmospheric pressure Pe.

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

In this way, the turbocharger 10 allows
Not only is efficient supercharging performed, but the exhaust braking effect can also be properly achieved.

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,
In this case, the third introduction passage may be an introduction passage without a valve, or may be opened and closed by a third valve separate from the valve members 34, 34.

[Effect of idea]

As described in detail above, in the variable displacement turbocharging device of the present invention, the valve members are arranged so as to follow the flow path of the other when seated on the valve seat, and when the valve seat is opened, the valve members Since the valve member is arranged along the flow path on the open side, the same valve member in the closed state is less likely to create resistance to the exhaust gas flowing to the other flow path, and the valve member in the open state is arranged along the flow path on the open side. This is less likely to create resistance to the exhaust gas flowing into the flow path, and as a result, the exhaust gas is smoothly sent into the turbine housing, resulting in the effect that the output of the engine can be improved.

In addition, since the valve member is a swing type that is swung by a swinging arm, when the valve member opens, it does not block the opening at all, and the exhaust gas smoothly passes through the opening and is sent to the turbine housing. , the effect of improving the output of the engine is achieved.

Furthermore, since it is a swing-type valve device in which the valve member is swung by a swinging arm and closes the opening by contacting the valve seat around the opening, the contact area is large, so the valve member The effect is that there is less wear and the durability of the valve member is improved.

Furthermore, when operating the exhaust brake, regardless of the engine speed,
Since the controller detects a predetermined pressure before the exhaust pressure adversely affects the valve train system and opens the valve member, the exhaust valve is less likely to be pushed open by sudden high pressure, and the exhaust pressure is sufficient to exhaust the exhaust valve. It is used for brakes, improves engine durability, and prevents noise from the intake system.

[Brief explanation of the drawing]

Figures 1 to 5 show a variable capacity turbocharger as an embodiment of the present invention. Figure 1 is a schematic diagram showing its overall configuration, Figure 2 is a flow chart showing its operation, and Figure 3 is a flowchart showing its operation. Figures 5 to 5 are graphs showing the respective characteristics. 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, 52 ... controller,
53...Exhaust pressure sensor, A, B...Exhaust gas introduction path, C...Valve control mechanism, Pe...Exhaust pressure, Peo...
...Pressure, S1-S7...Step, V...Valve device.

Claims (1)

[Scope of utility model registration request] a turbine housing provided with two exhaust gas introduction passages having different flow characteristics; a valve casing interposed between the turbine housing and the exhaust manifold; A partition wall extending to the middle part on the manifold side and forming two flow passages each communicating with the exhaust gas introduction passage, and two planes intersecting along the edge of the partition wall on the middle part side and one of the above-mentioned planes. A valve seat formed to have openings in each of the two planes, the plane of which is formed as an exhaust gas passage wall to the other flow passage, and the valve casing that opens and closes both valve seats, respectively. two valve members that open downstream in the exhaust gas flow direction and are each formed along the flow path through two swinging arms that are each pivotally supported by the valve; and a valve that opens and closes the two valve members, respectively. The controller includes a control mechanism, an exhaust pressure sensor that detects exhaust pressure in the exhaust manifold, and a controller that outputs an opening/closing signal for the valve member to the valve control mechanism based on a detection signal of the exhaust pressure sensor. When the exhaust brake is activated, when the exhaust pressure is detected to be above a predetermined pressure, a signal is sent to the valve control mechanism to open either one of the two valve members, and when the exhaust pressure is detected to be below the predetermined pressure, the two valve members are sent to the valve control mechanism. A variable displacement turbo supercharging device, characterized in that the open/close state of two valve members is detected and a signal is sent to the valve control mechanism to close the open valve member.