JPH0520567B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention is characterized in that the exhaust gas of an engine drives an exhaust gas turbine, and the turbine drives a compressor that pressurizes air supply to the engine. This invention relates to improvements to turbocharging devices.

Prior Art Engines for vehicles such as automobiles are operated over an extremely wide speed range from idle speed to maximum 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 is provided in the turbine housing to divide the exhaust gas inflow path in the same housing into two or more exhaust gas inflow paths with different flow characteristics, and
A valve device is provided in one or more of the divided exhaust gas inflow paths, 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 to obtain a braking effect on the vehicle by the exhaust pressure when the valve is closed.

Problems to be Solved by the Invention By the way, in the exhaust gas turbine of such a conventional variable displacement turbocharger, various technical problems have been solved regarding the arrangement and structure of the valve device for opening and closing the two or more divided exhaust gas passages. There was a problem. One of the most important problems is that the exhaust gas path changes when the valve is opened and closed, but in both cases, the flow path is as gentle as possible when the valve is opened or closed. The objective is to obtain a suitable shape, that is, to reduce the flow path resistance as much as possible and reduce the pressure loss of the exhaust gas.

In addition, the next important problem is that the partition walls that form the two or more divided exhaust gas inflow passages cannot be formed close to each other because the partition walls that form the two or more divided exhaust gas inflow passages will hit the outer circumference of the turbine rotor and be damaged due to thermal expansion due to heating. There was a technical problem.

Moreover, since the turbine housing of the turbocharger is manufactured by casting, very high precision cannot be expected.

For this reason, it is difficult to form the above-mentioned partition wall and the turbine rotor close to each other with high precision, and the gap between the above-mentioned partition wall and the turbine rotor must be formed to be large.

In the case of a turbocharging device formed in this manner, the exhaust gas inflow path from the tip of the partition wall to the turbine rotor suddenly expands, resulting in a problem that loss occurs.

In addition, in conventional exhaust brake valves, in order to prevent adverse effects on the valve train, a small hole is formed in the exhaust brake valve to prevent the exhaust pressure from rising above a required pressure even when the valve is closed.

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

Therefore, in an attempt to solve these problems, the present invention provides at least two inlets separated by a partition wall in the exhaust gas introduction portion of the turbine housing, and each of the inlets is connected via a valve device. is connected to the engine's exhaust system, that is, the manifold, and the inlet area for introducing exhaust gas into the turbine housing is changed by selecting the opening/closing operation of each valve device, thereby enabling variable capacity supercharging. Since the valve device is opened and closed on the upstream side of the valve seat, the device itself can be made compact, and the device can also be made more compact by downsizing the actuator for operating the valve device. In addition, the system is designed to provide sufficient exhaust braking effect over the entire engine speed range, and to perform supercharging according to the engine operating conditions during normal operation. The purpose is to provide the following.

Means for Solving the Problems The present invention provides at least two inlets partitioned by a partition wall in the exhaust gas introduction portion of the turbine housing, and the inlets are connected to the exhaust system of the engine through a valve device, respectively. That is, in a device connected to an exhaust manifold, the valve device includes a valve seat provided at the inlet of the turbine housing, and a valve member supported on a swinging arm that cooperates with the valve seat to open and close the exhaust gas passage. A support shaft is formed at the end of the swing arm, the support shaft is supported by an exhaust manifold on the side of the inlet, and the swing arm is rotated from the upstream side of the exhaust gas to the downstream side. This is a variable displacement turbo supercharging device characterized in that the valve member is brought into contact with the valve seat to completely seal the inlet, and the valve device allows the valve member to be placed on the swing arm with an appropriate play. When the valve member is not circular, it is movably supported, and when the valve member is not circular, it forms a rotation stopper, and when the opening and closing of the valve device toward the upstream side of the valve seat is operated by an actuator such as an air cylinder, it is possible to use a valve with a large flow path area. When the member is in operation, an actuator of an air cylinder that operates a valve member with a small flow path area is operated as an auxiliary actuator, and when the engine brake is in operation, the valve device is fully closed. The present invention is characterized in that it can also be used as an exhaust brake device.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. As shown in FIG. gas turbine 12
This is a compressor driven by. The exhaust gas turbine 12 includes a turbine housing 18 that accommodates a rotor 16, and inside the housing 18, exhaust gas passages each having different flow characteristics are divided in the rotor axial direction by a radial partition wall 20. That is, scrolls A and B are provided.

Further, the exhaust gas inlet 22 of the housing 18
is connected to an engine exhaust system, that is, an exhaust manifold 26.

Note that the exhaust gas inlet 22 is provided with the partition wall 2.
Inlets 22a and 22b are provided which are separated by an extended portion of 0 and are continuous to the exhaust gas passages A and B, respectively, and valve seats 32a and 32b are provided in the inlets 22a and 22b, respectively. The valve seats are opened and closed by valve members 34a and 34b, respectively.

The valve members 34a and 34b each have a protruding shaft 3 on the back surface thereof.
6a, 36b, and the protruding shafts 36a, 36b each have sufficient play in the radial direction to allow the swing arm 38
The swing arms 38a and 38b are supported by the free ends of the swing arms 38a and 38b, and the other ends of the swing arms 38a and 38b are fixed to support shafts 40a and 40b which are pivoted with bushings on the side wall of the manifold 26 connected to the inlet of the turbine housing. ing.

Above, the valve device will be further explained with reference to FIG.
The exhaust gas inlet 22 of the turbine housing 18 includes an inlet 22a, which is continuous with the exhaust gas passages A and B.
22b, the inlets are valve seats 32a and 32b, and a bushing 40 is provided on the side wall of the manifold 26, which is an engine exhaust device connected to the exhaust gas inlet 22.
swinging arms 38a, 38 that support valve members 34a, 34b with protruding shafts 36a, 36b;
b is fitted and integrated with the support shafts 40a, 40b, and pivotally supported by the bushes 40c, 40d. In order to control high-temperature exhaust gas, these materials are used for the support shaft 4 when, for example, martensitic chromium carbide precipitated steel is used for the bushes 40c and 40d.
0a, 40b and the swing arms 38a, 38b are made of martensitic steel, and when zirconia or alumina ceramic is used for the bushing, martensitic steel with chromium carbide precipitation is used for the support shaft and swing arms. , a combination that overcomes wear resistance at high temperatures and without lubrication.

Although the valve members 34a and 34b are supported on the free ends of the swing arms 38a and 38b by spherical seats, they do not necessarily have to be spherical seats, and may be supported by flat seats. You can also
In this case, it is desirable to provide an appropriate clearance between them in the axial direction of the protruding shafts 36a, 36b, and in relation to the cross-sectional shape of the exhaust gas passage formed by the partition wall 20 of the turbine housing inlet 22, the valve seat 32a , 32b may be a rectangle, an oval, or an ellipse. Correspondingly, of course, it is desirable that the shapes of the valve members 34a, 34b are roughly similar to the shapes of the valve openings of the valve seats 32a, 32b, and when such shapes are used, the shapes shown in FIGS. 3A and 3B are similar. As shown in FIG.
Stopper member 40 to prevent a and 34b from rotating.
e, 40f are provided. The stopper member is the valve member 3.
The valve member 34 is a plate body having a bent portion holding down the side walls of the valve members 34a and 34b.
Tighten together with a and 34b.

In addition, in the figure, 50a and 50b are pneumatic, hydraulic, or electric actuators for operating the valve device.

In the above device, the support shaft 4 opens and closes the valve members 34a and 34b via the swing arms 38a and 38b.
0a and 40b are connected to appropriate actuator devices, such as air cylinders, and are opened and closed depending on the operating conditions such as the rotation speed and load of an engine (not shown). Also, in the illustrated apparatus, exhaust gas passage A within turbine housing 18 is shown to have a greater flow rate characteristic than passage B.

Therefore, the exhaust gas introduction portion of the turbine housing is provided with at least two inlets separated by a partition wall, and a valve device is provided to open and close each of the inlets in order to vary the supercharging capacity. A valve control mechanism is provided that keeps the valve device closed when the pressure on the upstream side of the device is below the required pressure, and opens one of the valve devices when the pressure increases to the required pressure or higher. There is. With this configuration, 2
The inlets are now opened and closed by valve devices,
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 only when the pressure exceeds the required pressure, which has a negative effect on other valve systems, does the valve operate. The device is opened and the upstream side of the valve device is maintained at a maximum pressure below the required pressure.

By the way, since the valve device of the variable displacement turbocharger of the present invention has a structure that opens and closes on the upstream side of the valve seat, the flow path area is large, that is, the valve member 3 of the exhaust gas passage A has a large flow path area.
4a was difficult to open due to the large exhaust pressure received. Therefore, when switching the valve device, for example, using an air cylinder, when opening the valve member 34a, the flow path area is small, that is, the exhaust gas The lever 38c opens and closes the valve member 34a of the exhaust passage A so that the air cylinder that operates the valve member 34b of the gas passage B assists.
and a lever 38d for opening and closing the valve member 34b of the exhaust passage B.
The lever 38c of the exhaust gas passage A of the link 38f is engaged with the elongated hole 38g in a pivoting manner.

Function: The actuator 50 is attached to the swinging arms 38a, 38.
a, 50b and a fluid pressure source that supplies operating pressure to the actuator, and when the valve members 34a, 34b are closed, the exhaust pressure of the exhaust manifold 26 on the upstream side exceeds the required pressure. When the valve member 34a becomes loose, the valve member 34a is opened against the air pressure within the actuator 50a.

Therefore, the variable capacity turbocharger of the present invention is suitable for low speed and high load operation of the engine (region _B1 in Fig. 5).
, the valve member 34a is closed and the valve member 34a is closed.
b is opened, and the exhaust gas from the exhaust manifold 26 acts on the blades of the turbine rotor 16 from the inlet 22b of the turbine housing through the valve opening of the valve seat 32b, through the exhaust gas introduction path B, and as shown in FIG.
Due to the flow rate characteristic shown in B ₁ , the exhaust gas turbine 1
2 is operated efficiently.

In addition, the engine is at medium speed and under high load (see Figure 5).
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 .

Furthermore, during high-speed, high-load and low-load operation of the engine (area _B3 in FIG. 5), the two valve members 34a and 34b are
are both opened, and the inflowing exhaust gas flows into the inlets 22a and 22b of the turbine housing, respectively, and the flow rate characteristics are determined from both the exhaust gas introduction paths A and B.
B ₃ supplies the turbine rotor 16.

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 becomes closed, and the exhaust pressure inside the exhaust manifold 26 increases.
Pe provides an exhaust braking effect.

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 system, the valve member 34a does not open against the air pressure in the actuators 50a and 50b, and the exhaust pressure Pe is completely sealed. Therefore, a braking effect can be obtained by the highest exhaust pressure Pe at that rotation speed.

In addition, when the engine is operated in a medium to high speed range, when 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 is operated by the actuator 50a,
It is operated to open against the air pressure in 50b.

After this, the valve member 34 is moved to a position where the pressing force by the actuators 50a and 50b and the exhaust pressure Pe are balanced.
a is opened, and the exhaust pressure in the exhaust manifold 26
Pe is held at pressure Peo.

That is, as shown by the dotted line in Fig. 7, in the past, 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 the present invention, 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 changed to Peo. Since the opening degree of the valve member 34a is automatically adjusted so that the maximum exhaust pressure Pe at the engine rotation speed is the exhaust pressure of the exhaust brake, regardless of the engine rotation speed, the maximum exhaust pressure Pe at the engine rotation speed is limited to the required pressure Peo.
Acts as Pe.

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

In this way, the variable displacement turbocharger 10 performs efficient supercharging and also provides an appropriate exhaust braking effect.

Note that if this variable displacement turbocharger is used, a conventional exhaust brake is not required, which reduces costs accordingly.

By the way, the operation of the link 38f mechanism that assists the valve member 34a of the exhaust gas passage A, which has a large flow path area so that the valve device opens and closes on the upstream side of the valve seats 22a and 22b, will be explained as shown in FIG. The state is that the valve member 3 of the exhaust gas passage A with a large flow passage area
4a is closed and the valve member 34b of the exhaust gas passage B, which has a small flow area, is open, and the assisting action of the link 38f is not performed. Next, the opening operation is difficult due to the exhaust pressure load because the flow path area is large. To open the valve member 34a of the exhaust gas passage A, the actuator 50a of the valve member 34a also operates the actuator 50b of the exhaust gas passage B, and the actuator 50b of the exhaust gas passage B cooperates with the actuator 50a of the valve member 34a to assist in the opening operation. However, when opening the valve member 34b of only the exhaust gas passage B,
The pin 38p formed at one end of the lever 38c of the valve member 34a having a large flow path area slides through the slit 38g of the link 38f, and does not act on the valve member 34b.

Example Hereinafter, an example will be explained.
If the valve members 34a, 34b shown in B are not circular, a rotation stopper is required due to the seating relationship with the valve seats 32a, 32b. Stopper portions 40g, 40h are formed at the corners, and even if the valve members 34a, 34b try to rotate, the stoppers abut against the support shafts 40a, 40b, making it impossible.

Next, the valve members 34a, 34 shown in FIG.
When b is rectangular as described above, as an example considering the difficulty of opening due to the exhaust pressure of the valve member, the protruding shaft 36a of the valve member, By shifting the support point of 36b toward the support shafts 40a, 40b, the swinging arms 38a,
38b is shortened.
Therefore, against the exhaust gas pressure, the valve members 34a, 3
In order to open 4b, if the cross-sectional center of the flow path and the support point of the valve member coincide, a force of the same magnitude as the exhaust gas pressure is required, but if the support point of the valve member is aligned with the support point of the flow path cross-section. Since the valve members 34a, 34b are offset from the center toward the support shafts 40a, 40b, the opening force acts on the support shafts 40a, 40b using the abutting portions of the valve members 34a, 34b and the valve seat as fulcrums.
The rear end portions of the valve members 34a, 34b are opened in a lifted state, and exhaust gas flows through the gap in this open portion, reducing the pressure difference on both sides of the valve member. This allows the valve member to be opened with a small force. Therefore,
Offsetting the support points in this manner results in a more compact actuator for opening the valve member.

Furthermore, as an example of the partition wall 20 that partitions the exhaust gas introduction part of the turbine housing 18, the tip of the partition wall is made of martensite for a ring-shaped housing made of, for example, spheroidal graphite cast iron, as a measure against damage caused by thermal stress. It is considered that the annular member may be formed by casting another member with a low expansion coefficient such as stainless steel, but as a better measure against damage to the annular member, a slit 20a as shown in FIGS. 10A and 10B may be used. Structure, division 2 as shown in Figure 10C
A 0b structure may be used, which absorbs deformation due to thermal expansion and prevents damage. Incidentally, as shown in FIG. 11, a support 20c may be provided to prevent the exhaust gas passage B from becoming narrower due to deformation of the partition wall.

Effects As a result of the above, according to the variable capacity turbocharging device of the present invention, the exhaust gas introduction portion of the turbine housing is provided with at least two inlets separated by a partition wall, and the turbocharging capacity is made variable. A valve device is equipped to open and close each of the above-mentioned inlets, and when the pressure on the upstream side of the valve device is below the required pressure, the above-mentioned valve device is kept closed, and when the pressure rises above the required pressure, the above-mentioned valve device is closed. It has a simple configuration in which a valve control mechanism is provided to open either one of the This has the advantage that the exhaust gas can be efficiently supplied to the exhaust gas turbine according to the operating condition of the engine using an inexpensive device.

In addition, when operating the exhaust brake, the exhaust pressure is fully utilized for the exhaust brake without adversely affecting the valve train, regardless of the engine rotation speed, and the advantage is that sufficient exhaust braking effect can be obtained. be.

In addition, the actuator of the valve member with a small flow path area cooperates with the opening operation of the valve member with a large flow path area, thereby eliminating unnecessary enlargement of the actuator, and making the device smaller and more compact.

Furthermore, even if a non-circular valve member is used, providing a rotation stopper will prevent the valve member from becoming uncomfortable with the valve seat, and in addition, in cases where the valve member is rectangular, etc. By making the support point eccentric, it becomes a force multiplier mechanism, and by making the actuator smaller, it can be made even more compact.

[Brief explanation of the drawing]

Fig. 1 is an overall structural diagram of a variable capacity turbocharger, Fig. 2 is a structural diagram of a valve device, and Fig. 3 is a structural diagram showing a rotation prevention structure of a valve member of the valve device. A is a cross-sectional view, and B is a plan view. FIG. 4 is a diagram of a mechanism in which an actuator with a small flow path area assists the opening operation of a valve member with a large flow path area. FIG. 5 is an engine operating state graph, FIG. 6 is a flow rate characteristic graph, and FIG. 7 is an exhaust brake effect graph. FIG. 8 is a structural diagram of another embodiment for preventing rotation of the valve member, in which A is a plan view and B is a side sectional view. Fig. 9 is a structural diagram of a valve device in which the support point of the valve member is eccentric, and Fig. 10 is a structural diagram of an example structure with measures taken against damage to the partition wall, where A is a structure diagram of an embodiment of the valve device in which the support point of the valve member is eccentric. It is a structural phase diagram with a slit in B.
1 is a structural diagram in which slits are made in a staggered manner on the inside and outside of a separate member, and C is a structural diagram in which a separate member is made into a split type. FIG. 11 is a structural diagram of a partition wall provided with supports to prevent narrowing of the exhaust gas passage due to thermal deformation. 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, 32a, 32b...Valve seat, 34
a, 34b...valve member, 36a, 36b...protruding shaft, 38a, 38b...swinging arm, 38c, 38d
...Lever, 38f...Link, 38g...Elongated hole, 38p...Pin, 40a, 40b...Support shaft, 40c, 40d...Button, 40e, 40
f... Stopper member, 50a, 50b... Actuator, A, B... Exhaust gas passage, 20a...
Slit of partition ring, 20b... Divided portion of partition ring, 20c... Support of partition ring.

Claims (1)

[Claims] 1. In the exhaust gas introduction part of the turbine housing,
In a variable capacity turbocharger provided with at least two inlets 22a, 22b partitioned by a partition wall 20, each of which is connected to an exhaust manifold 26 via a valve device, the valve device is connected to the exhaust manifold 26. It consists of valve seats 32a, 32b provided at the inlet of the turbine housing, and valve members 34a, 34b supported on swing arms 38a, 38b, which cooperate with the valve seats to open and close the exhaust gas passages A, B. , forming support shafts 40a and 40b at the ends of the swinging arms, supporting the support shafts on the exhaust manifold at the side of the inlet, and rotating the swinging arms from the upstream side of the exhaust gas to the downstream side; A variable capacity turbocharger characterized in that the valve member is brought into contact with a valve seat to completely seal the inlet. 2 At the exhaust gas introduction part of the turbine housing,
In a variable capacity turbocharger provided with at least two inlets 22a, 22b partitioned by a partition wall 20, each of which is connected to an exhaust manifold 26 via a valve device, the valve device is connected to the exhaust manifold 26. It consists of valve seats 32a, 32b provided at the inlet of the turbine housing, and valve members 34a, 34b supported on swing arms 38a, 38b, which cooperate with the valve seats to open and close the exhaust gas passages A, B. , forming support shafts 40a and 40b at the ends of the swinging arms, supporting the support shafts on the exhaust manifold at the side of the inlet, and rotating the swinging arms from the upstream side of the exhaust gas to the downstream side; The valve members 34a, 34 are brought into contact with the valve seat to completely seal the inlet.
A variable capacity turbocharger characterized in that b is provided with a rotation stopper. 3 At the exhaust gas introduction part of the turbine housing,
In a variable capacity turbocharger provided with at least two inlets 22a, 22b partitioned by a partition wall 20, each of which is connected to an exhaust manifold 26 via a valve device, the valve device is connected to the exhaust manifold 26. It consists of valve seats 32a, 32b provided at the inlet of the turbine housing, and valve members 34a, 34b supported on swing arms 38a, 38b, which cooperate with the valve seats to open and close the exhaust gas passages A, B. , forming support shafts 40a and 40b at the ends of the swinging arms, supporting the support shafts on the exhaust manifold at the side of the inlet, and rotating the swinging arms from the upstream side of the exhaust gas to the downstream side; The actuator 50b brings the valve member into contact with the valve seat, completely sealing the inlet, and opens the valve member 34b with a small flow path area. A variable capacity turbocharger characterized in that the variable capacity turbocharger is linked to assist in opening operation by an actuator 50a. 4 At the exhaust gas introduction part of the turbine housing,
In a variable capacity turbocharger provided with at least two inlets 22a, 22b partitioned by a partition wall 20, each of which is connected to an exhaust manifold 26 via a valve device, the valve device is connected to the exhaust manifold 26. It consists of valve seats 32a, 32b provided at the inlet of the turbine housing, and valve members 34a, 34b supported on swing arms 38a, 38b, which cooperate with the valve seats to open and close the exhaust gas passages A, B. , forming support shafts 40a and 40b at the ends of the swinging arms, supporting the support shafts on the exhaust manifold at the side of the inlet, and rotating the swinging arms from the upstream side of the exhaust gas to the downstream side; The valve member is brought into contact with the valve seat to completely seal the inlet, and when the pressure on the upstream side of the valve device is below the required pressure when the exhaust brake is activated, the valve device is kept in a closed state and the pressure exceeds the required pressure. 1. A variable displacement turbo supercharging device characterized by being provided with a valve control mechanism that opens one of the valve devices when the pressure is increased.