JPH09222024A - Exhaust bypass device of turbo supercharged engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent exhaustion interference in the upstream side of a turbine impeller so as to effectively utilize exhaust pulsation by providing first and second bypass passages branching from first and second exhaust passages and connecting the exit of each bypass passage to an exhaust exit passage facing the exhaust port of the turbine impeller. SOLUTION: An exhaust manifold 4 collects the exits of exhaust ports #1 to #3 and #4 to #6. Two rooms 6 and 7 are formed by a partition wall 5 and the rooms 6 and 7 are communicated with first and second scroll rooms inside a turbine house via the exhaust exit ports 6a and 7a. The exhaust manifold 4 includes an exhaust taking out part 25, first and second exhaust taking-out passages 26 and 27 are formed in this part and the passages 26 and 27 are opened/closed by opening/closing valves 29 and 30. During the opening of the opening/closing valves 29 and 30, the exhausts of the rooms 6 and 7 are sent out through first and second bypass piping lines 37 and 38 to the exhaust exit passage 21 and the turbine impeller is bypassed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention particularly relates to an exhaust bypass device for an engine equipped with a twin entry turbocharger.

[0002]

2. Description of the Related Art There is known a turbocharger of a twin-entry type in which exhaust gas is separately sent from two scroll chambers to drive a turbine impeller to rotate. Especially in a multi-cylinder engine, this prevents exhaust interference between cylinder groups and positively utilizes exhaust pulsation, and due to dynamic pressure supercharging, for example, even in a low revolution range where the exhaust flow rate is small,
The input energy is increased so that the rise of turbine rotation can be improved.

In the engine in which the turbocharger is combined, the exhaust manifold has a dual structure, that is, the exhaust manifold is internally partitioned or has a completely divided structure so that the exhaust port outlets are gathered in predetermined cylinders. It is said that. Exhaust gas is sent individually from these exhaust manifolds to the respective scroll chambers, thereby preventing exhaust interference on the upstream side of the turbine impeller.

By the way, in the supercharging pressure control of the turbocharger, a part of the exhaust gas is bypassed and sent from the upstream side to the downstream side of the turbine impeller to reduce the flow rate of the exhaust gas to be sent to the turbine impeller to thereby supercharge It is known to reduce pressure.

FIG. 4 shows a conventional exhaust bypass device for doing this. As shown in the figure, the exhaust manifold a is divided into two parts by partitioning the inside so that exhaust gas is individually sent from each outlet b, c to each scroll chamber. It has become. The exhaust manifold a is formed with an exhaust extraction portion d, and two passages e and f are formed in this portion, and the common opening / closing valve g opens and closes the passages e and f, and one passage h on the downstream side thereof. The exhaust gas is merged and bypassed to the downstream side of the turbine impeller.

[0006]

However, with this structure, when the supercharging pressure rises and the on-off valve g is opened, the passages e and f are communicated with each other and the exhaust gas in each internal chamber of the exhaust manifold a is exhausted. However, there is a drawback that exhaust gas interference occurs on the upstream side of the turbine impeller, the pulsation is attenuated, and the efficiency of the turbocharger is reduced.

[0007]

An exhaust bypass device for a turbocharged engine according to the present invention comprises a first exhaust passage for collecting the outlets of exhaust ports of a predetermined cylinder among exhaust ports of a multi-cylinder engine, A second exhaust passage that collects the outlets of the remaining exhaust ports is provided, and the outlets of these exhaust passages are made to face the exhaust inlet of the turbine impeller, respectively, and the exhaust outlet passage is made to face the exhaust outlet of the turbine impeller. And branching from the first and second exhaust passages to provide first and second bypass passages, respectively, and connecting the outlets of the first and second bypass passages to the exhaust outlet passage, First and second on-off valves are provided in the first and second bypass passages, respectively.

In this structure, the bypass passages are independent of each other, and the bypass passages are opened and closed by individual opening / closing valves. Therefore, even if the on-off valve is opened, the bypass passages are not communicated with each other, whereby exhaust interference on the upstream side of the turbine impeller is prevented, and exhaust pulsation can be fully utilized.

[0009]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 2 is a plan view showing the entire engine to which the exhaust bypass device according to the present invention is applied.

As shown, the engine 1 has a series 6
It is a cylinder, and from the timing pulley 2 side (right side) in order #
1 ... # 6 Cylinders 3 ₁ ... 3 ₆ are included. Each cylinder 3 ₁ ... to respectively corresponding to the # 1 ... # 6 exhaust ports (not shown) is communicated. An exhaust manifold 4 is attached to the cylinder head so as to communicate with these exhaust ports.

The exhaust manifold 4 has a partition wall 5 in the center thereof.
Has its inner chamber divided into two chambers. Specifically, the first chamber 6 collects the outlets of the # 1 ... # 3 exhaust ports, and the second chamber 7 collects the outlets of the # 4 ... # 6 exhaust ports. The turbine housing 9 of the turbocharger 8 is connected to the exhaust manifold 4.

FIG. 3 shows a turbine portion of the turbocharger 8. As shown in the drawing, the turbocharger 8 has a twin entry type structure. Inside the turbine housing 9, there are two scroll chambers 1 partitioned by a partition wall 10.
1, 12 are independently formed in parallel, and the scroll chamber 1
Reference numerals 1 and 12 form first and second exhaust gas introduction paths for introducing exhaust gas into the turbine impeller 13, respectively. First
The scroll chamber 11 is communicated with the first chamber 6 described above, and the second scroll chamber 12 is communicated with the second chamber 7 described above. The outlets inward in the radial direction of the scroll chambers 11 and 12 are
The turbine impeller 13 is opened so as to face the exhaust inlet 14 radially outward.

The turbine impeller 13 is the turbine shaft 1.
5, which is integrally attached to one end of the turbine shaft 1
A compressor wheel (not shown) is attached to the other end of 5. The turbine shaft 15 is rotatably supported by the bearing portion 17 of the center casing 16.

The turbine impeller 13 has an exhaust outlet 18 at its axial end portion, and the turbine housing 9 has an exhaust outlet portion 19 surrounding the exhaust outlet 18. An exhaust pipe 20 (shown in FIG. 2) is connected to the exhaust outlet portion 19, and the exhaust outlet portion 19 and the exhaust pipe 20 define an exhaust outlet passage 21 facing the exhaust outlet 18 of the turbine impeller 13.

Similarly, the first chamber 6 and the first scroll chamber 11, and the second chamber 7 and the second scroll chamber 12 described above respectively face the exhaust inlet 14 of the turbine impeller 13 with the first exhaust gas. The passage 22 and the second exhaust passage 23 are separately formed (see FIG. 2). As shown in FIG. 2, when the turbine impeller 13 is driven by exhaust gas, the compressor wheel in the compressor housing 24 rotates to feed intake air into each cylinder 3 ₁ ... In a supercharged state. Especially # 1 ...
The exhaust gas of the # 3 cylinders 3 ₁ ... 3 ₃ is discharged from the first exhaust passage 22.
Are collected and sent to the turbine impeller 13, while the exhaust of the # 4 ... # 6 cylinders 3 ₄ ... 3 ₆ is collected in the second exhaust passage 23 and sent to the turbine impeller 13 in a system different from this. Be done. In this way, since the exhaust gas is sent to the turbine impeller 13 by another system, mutual interference of the exhaust gas is prevented, exhaust pulsation can be positively utilized, and highly efficient dynamic pressure supercharging can be achieved.

By the way, in controlling the supercharging pressure, it is necessary to avoid the turbine impeller 13 and bypass the exhaust gas. A device for performing this will be described in detail below.

As shown in FIG. 1, the exhaust manifold 4 has an exhaust outlet port 6 for communicating the first chamber 6 and the second chamber 7 with the first and second scroll chambers 11 and 12, respectively.
a and 7a are formed. On the other hand, an exhaust outlet 25 is formed in the exhaust manifold 4 and includes a first chamber 6 and a second exhaust chamber 25.
First and second exhaust gas extraction passages 2 that respectively communicate with the chamber 7.
6, 27 are formed. These passages 26 and 27 are opened at the upper end surface 28 of the exhaust outlet 25, and in particular, the upper end surface 28
Form a valve seat for the first and second on-off valves 29, 30.

The first and second on-off valves 29, 30 are configured as a swing valve, and here, are connected to a common shaft 31 via first and second stays 32, 33,
By rotating the shaft 31 about its axis, the outlets of the first and second exhaust outlet passages 26 and 27 are individually opened and closed synchronously. The shaft 31 integrally has a lever 34 at its end, and the lever 34 is pushed and pulled by a dashpot 35 (actuator) to rotate about the axis. When the intake air from the intake pipe 36 (shown in FIG. 2) is introduced into the dashpot 35 and the intake pressure becomes equal to or higher than the set supercharging pressure, the dashpot 35 pushes the lever 34 in accordance with the pressure, and the first And, the second opening / closing valves 29, 30 are simultaneously opened by an appropriate amount.

The exhaust outlet 25 has a first and a second
Bypass pipes 37 and 38 are connected, and these pipes 3
7 and 38 are individually communicated with the first and second exhaust extraction passages 26 and 27, respectively. Furthermore, these bypass piping 3
As shown in FIG. 2, the exhaust outlet ends of the exhaust pipes 7, 38 are connected to the exhaust pipe 20.
Connected to.

As described above, the first exhaust outlet passage 26 and the first bypass pipe 37 and the second exhaust outlet passage 27 and the second bypass pipe 38 are connected to the first and second exhaust passages 22, 23 are respectively branched to form a first bypass passage 39 and a second bypass passage 40 for bypassing the exhaust gas by another system. Then, the first and second on-off valves 29 and 30 individually open and close these passages.

Now, according to this structure, when the first and second on-off valves 29, 30 are opened, the first chamber 6
Exhaust gas from the first and second chambers 7 is supplied to the first and second bypass passages 3
It is sent to the exhaust outlet passage 21 through 9, 40. That is, the exhaust gas is bypassed from the upstream side of the turbine impeller 13 to the downstream side through a passage of another system. And open / close valve 2
Since 9 and 30 open and close each passage separately, the passages do not communicate with each other at the time of opening, and therefore the exhaust gas does not join.

Therefore, the interference of the exhaust gas on the upstream side of the turbine impeller 13 is prevented, whereby the damping of the exhaust gas pulsation is prevented, and the exhaust gas pulsation can be sufficiently utilized for driving the turbine. Even in an operating region where the supercharging pressure control is performed, the performance of the turbocharger does not have to be degraded, and high efficiency can be maintained.

The exhaust gas bypassed by another system joins in the exhaust pipe 20, but this position is the turbine impeller 13
Since it is on the downstream side, and the distance for the passage is maintained sufficiently to the upstream side, this has no effect and the advantage of dynamic pressure supercharging is not impaired.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and other embodiments can be adopted. For example, the exhaust gas is taken out of the turbine housing 9 and bypassed, or the on-off valves 29, 3
It is also possible to separately operate the actuators without linking 0. Further, the opening / closing valves 29 and 30 may be servo valves, or the two bypass pipes 37 and 38 may be integrated into one to provide a partition inside. Further, the number of cylinders other than 6 cylinders can be applied to the engine 1 as well.

[0026]

The present invention exhibits the following excellent effects.

(1) In supercharging pressure control, exhaust interference on the upstream side of the turbine impeller can be prevented, exhaust pulsation can be fully utilized, and efficiency reduction can be prevented.

[Brief description of drawings]

FIG. 1 is a front view showing an exhaust bypass device according to the present invention.

FIG. 2 is a plan view showing the entire engine to which the exhaust bypass device according to the present invention is applied.

FIG. 3 is a vertical sectional view showing a turbocharger.

FIG. 4 is a front view showing a conventional exhaust bypass device.

[Explanation of symbols]

 1 Engine 13 Turbine Impeller 14 Exhaust Inlet 18 Exhaust Outlet 21 Exhaust Outlet Passage 22 First Exhaust Passage 23 Second Exhaust Passage 29 First Open / Close Valve 30 Second Open / Close Valve 39 First Bypass Passage 40 Second Bypass passage

Claims (1)

[Claims] 1. A first exhaust passage for gathering the outlets of the exhaust ports of a predetermined cylinder among exhaust ports of a multi-cylinder engine, and a second exhaust passage for gathering the outlets of the remaining exhaust ports are provided. The outlet of the exhaust passage faces the exhaust inlet of the turbine impeller, and the exhaust outlet passage is provided so as to face the exhaust outlet of the turbine impeller. The exhaust outlet passage is branched from the first and second exhaust passages to form the first and second exhaust passages. Second bypass passages are respectively provided, and the outlets of the first and second bypass passages are connected to the exhaust outlet passage, and the first and second bypass passages are connected.
An exhaust bypass device for a turbocharged engine, characterized in that first and second on-off valves are provided in the bypass passages of.