JPH01193024A - Supercharger for engine - Google Patents

Abstract

PURPOSE:To improve the durability of a switching means by constructing a change valve provided in an exhaust passage at the down stream of a supercharger turbine when the number of exhaust gas turbo type superchargers which should operate in response to the speed of revolution of an engine is changeably controlled by the switching means. CONSTITUTION:The respective exhaust port 3 of two groups of cylinders consisting of three cylinders respectively the firing order of which is discontinuous is connected to the first and collecting portion X1, X2 formed by a partition wall 32e in an in-line 6 cylinder engine. Respective collecting portion X1, X2 is connected to the exhaust gas introducing ports of the first and the second supercharger 22, 23 via branching exhaust passages 33, 34. In this case, a change valve 35 is provided at a branching exhaust passage 37 where exhaust gas passes through after it passes through a turbine 23b. Meantime, the change valve 35 is opening/closing-controlled to operate only a supercharger 22 at the time of a low speed, and to operate both supercharger 22, 23 at the time of a high speed. Accordingly, a chance to contact with dirty exhaust gas in a high temperature and a high pressure is reduced to improve its durability.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to an engine supercharging device that performs supercharging using a plurality of exhaust turbo superchargers6 (Prior art) Exhaust turbo In a type turbocharger, if the supercharging capacity is set to a large value, the response, especially at low speeds, will deteriorate, and it will be difficult to provide sufficient supercharging to ensure responsiveness. .

For this reason, as shown in Japanese Unexamined Patent Publication No. 56-41417, two exhaust turbo superchargers are installed so that only one supercharger operates at low speeds or low loads, while at high speeds or low loads, A system has been proposed in which two superchargers are operated together during high load operation. By doing this, it is possible to solve the problem of responsiveness at low speeds by making one supercharger that operates only at low rotational speeds or low f1 loads have excellent responsiveness. ii) It becomes possible to obtain sufficient supercharging capacity at high speeds.

(Problems to be Solved by the Invention) By the way, by using a plurality of exhaust turbo superchargers, it is possible to change the number or type of superchargers used depending on the operating condition.
That is, when changing the supercharging capacity, a switching means for this change is required. This switching means is generally
It is generally constructed by a switching valve that is an on-off valve that switches the flow of exhaust gas into and out of the turbine of the supercharger that is to be switched between activation and deactivation.

However, in this case, the switching valve is constantly exposed to exhaust gas, which tends to pose a problem in terms of its durability.

In order to prevent such a problem, it is conceivable to operate the supercharger at all times, and at the same time, to relieve the supercharging pressure from the supercharger that is to be switched between active and inactive using a relief valve. However, in this case, the supercharger, which is not cheap to perform supercharging, will be forced to do unnecessary work, making it difficult to employ.

Therefore, the object of the present invention is based on the premise that a plurality of exhaust turbo superchargers are used, and the number or type of superchargers to be operated can be changed depending on the operating state.
It is an object of the present invention to provide an engine supercharging device that can improve the durability of a switching means that performs this change without unnecessarily operating a supercharger.

(Means and operations for solving the problems) In order to achieve the above-mentioned object, the present invention has the following configuration. In other words, it is equipped with multiple exhaust turbo superchargers,
At low speeds, only some of the superchargers are operated to achieve a first state with low supercharging capacity, while at high speeds, at least the remaining superchargers are operated to achieve a second state with high supercharging capacity. In the supercharging device for an engine, the switching means for switching between activation and non-operation of the supercharger is constituted by a switching valve consisting of an on-off valve provided in an exhaust passage downstream of the turbine of the supercharger. The structure is as follows.

With such a configuration, the supercharger to be switched is activated or deactivated, that is, switched between the first state and the second state, by opening and closing the switching valve.

Since the switching valve is located in the exhaust passage downstream of the turbocharger's turbine, it comes into contact with exhaust gas only when the turbocharger is operating, which reduces its durability. Improved.

In addition, since high-pressure exhaust gas is always acting on the turbine inlet side of the supercharger that is subject to switching, the turbine will be rotated as soon as the switching valve is opened. Become. This is also advantageous in that it improves responsiveness when transitioning from the first state to the second state.

(Example) Hereinafter, an example of the present invention will be described based on the attached drawings.

In FIG. 1, reference numeral 1 denotes an engine body, which is an Otto type reciprocating in-line six-cylinder engine having six cylinders Ct to C6 in series with each other. Each cylinder C1~
An intake boat 2 and an exhaust boat 3 are opened at C6, and each boat 2 or 3 is opened and closed at a predetermined timing in synchronization with the rotation of the engine output shaft by an intake valve or an exhaust valve, respectively, which are not shown. The ignition order in each cylinder C1 to C6 is, for example, Cl-C5→C3-C6-C2
→ C4, and as a result, in the example, three cylinders C1 to C3 form a first cylinder group in which the ignition order (exhaust stroke) is not consecutive, and three cylinders 04 to C6 are set as ignition order (exhaust stroke). ) constitutes a non-contiguous second 'A double cylinder group.

An intake passage 11 for supplying intake air to each intake boat 2 is provided with a surge tank 12 in the middle thereof.

This surge tank 12 and each intake boat 2 are connected by independent intake passages 13a = 13f. The intake passage 11 on the upstream side of the surge tank 12 includes an upstream common intake passage 14 and a downstream common intake passage 15, and an air cleaner 16 and an air flow meter 17 are connected to the F downstream common intake passage 14. on the other hand,
An intercooler 18 and a throttle valve 19 are connected to the downstream common intake passage 15 .

The common intake passages 14 and 15 on the upstream side and the downstream side are connected by two branch intake passages 20 and 21, first and second, which are parallel to each other. This first branch intake passage 2
0, the compressor 22a of the first supercharger 22, which is an exhaust turbo type, is disposed, and the second branch passage 2! What is
Compressor 2 of the second supercharger 23 which is an exhaust turbo type
3a is provided. The first of the compressor 22a
The branch intake passage 20 and the second branch intake passage 21 downstream of the compressor 23a are connected by a bypass passage 24, and a bypass valve 25 consisting of an on-off valve is disposed in the bypass passage 24. In addition, the second branch intake passage 21
A cut valve 26 consisting of an on-off valve is disposed at the downstream end of the bypass passage 24 , that is, at a position downstream from the connection to the bypass path 24 .

On the other hand, exhaust passage 3! includes an exhaust manifold 32, and the exhaust manifold 32 has a first gathering portion x1 and a second gathering portion x2 defined by a partition wall 32e. For this first gathering part x1, three cylinders C1 to C3 forming the first cylinder group whose exhaust strokes do not overlap with each other are
The exhaust boats 3 are individually connected to each other by independent exhaust passages 32a to 32c. Also, 2nd gathering section x 2
In this case, the exhaust boats 3 of the three cylinders C4 to C6 forming the second cylinder group whose exhaust passage strokes do not overlap with each other are individually and independently connected by independent exhaust passages 32d to 32r.

No. 2 above. Exhaust gas from the second two collecting parts XI and X2 is passed through the first branch exhaust passage 33.

m1 is supplied to the turbine 22b of the first supercharger 22.

The scroll passage serving as the exhaust gas introduction passage of the first supercharger 22 is divided into two scroll passages 22 by a partition wall 22C.
d and 22e. On the other hand, the first branch exhaust passage 33 also has two passages 33A and 3 which are constructed by dividing two pipes by partition walls 33a.
3B, one passage 33A communicates the first collecting portion x1 with one scroll passage 22d, and the other passage 33A communicates with one scroll passage 22d.
B communicates the second collecting portion x2 with the other scroll passage 22e. Of course, the turbine 22b of the first supercharger 22
is connected to the compressor 22a via a shaft 23f.

Similarly, the second supercharger 23 also includes two scroll passages 23d% 23e defined by a partition wall 23c,
One scroll passage 23d passes through the passage 34A. The other scroll passage 23e is in communication with the gathering part x1.
is communicated with the second gathering portion x2 via the passage 34B. The second branch exhaust passage 34 constituting both roads 34Δ and 348 is formed as a short piece integrally with the intake manifold 32, that is, it is formed as a collection part of the intake manifold 32, and is formed as a collection part of the intake manifold 32. Partition wall 32 that partitions
e directly serves as a partition wall that separates both roads 34A and 34B. Of course, the turbine 23b of this second supercharger 23 is connected to the compressor 23 via the shaft 23r.
connected to a.

The exhaust gas after passing through the turbines 22b and 23b of both the superchargers 22 and 23 is routed through the branch exhaust passage 36 or 37.
It is then discharged. Although not shown, these re-branched exhaust passages 36 and 37 are finally merged into one, and a catalyst for exhaust gas purification is disposed downstream of this merged portion. And a branch exhaust passage 37 for the second supercharger 23
A switching valve 35 consisting of an on-off valve is provided. Also, 1st. The second superchargers 22 and 23 each have a WGB (
Wastegate valve) has an angle of 38.39°. In addition,
This WG838 (39) has two scroll passages 22d%22e (23d, 23) of the supercharger 22 (23).
There are two pieces corresponding to e), but only one of them is shown in the drawing.

Here, the first supercharger 22 is small in size, ie, has a small supercharging capacity, but has a responsiveness of +/min even at low speeds. On the other hand, the second supercharger 23 is large-sized, that is, has a sufficiently large supercharging capacity, although it is inferior in response.

Note that, as in the embodiment, the turbines 22b and 23b of the supercharger 22 and 23 are connected to each cylinder group whose exhaust strokes do not overlap.
By supplying exhaust gas to the engine, exhaust interference can be prevented and boost pressure can be further increased under the same operating conditions (improvement of turbine efficiency).

Figure 2 shows the bearings 22g and 23 of the 1-car supercharger 22.23.
An example of the configuration of a cooling water passage and an oil passage for g. In FIG. 2, a cooling water outlet 51 and an oil outlet 52 are installed at a high location in the engine body l. The cooling water taken out from the cooling water extraction part 51 is supplied to the bearing part 23g of the second supercharger 23 via the pipe 53. Further, the cooling water flows through the bearing portion 23g from the front side to the back side of the second figure, and then is supplied to the bearing portion 22g of the first supercharger 22 via the pipe 54. After the cooling water flows through the bearing portion 22g from the back side to the front side of the paper in the second drawing, it is returned to the heater bomb (the path shown in the drawing) via the piping 55.

] 2. The bearing portion 22g of the first supercharger 22 is connected to the second supercharger 2.
It is located at a lower position than the bearing portion 23g of No. 3.

Therefore, as will be described later, the first supercharger 22, which is frequently used and tends to become hot, has a higher temperature than the second supercharger 23, which is located at a higher place, when cooling water is circulated by boiling cooling that occurs after the engine is stopped. It will be more thoroughly cooled.

On the other hand, the oil from the oil extraction portion 52 is transferred to the piping 56
The fuel is supplied to the bearing portion 22g of the first supercharger 22 via.

This oil flows through the bearing portion 22g from the top to F in FIG. 2, and then returns to the oil pan 58 via the pipe 57.

In addition, the above oil is supplied to a pipe 59 branched from the pipe 56.
After flowing from the top to the bottom in FIG. 2 through the bearing portion 23g of the second supercharger 23, it is returned to the oil pan 58 via the pipe 60.

Reference numeral 71 in FIG. 1 is a control unit configured using a microcomputer. Signals from sensors 72 and 73 are input to this control unit 71, and signals from the control unit 71 are sent to actuators 75 to 79. output for The sensor 72 detects the engine rotation speed.

The sensor 73 detects the throttle opening. The actuator 75 is for driving the bypass valve 25 to open and close. Actuator 76 is cut valve 26
This is for driving the opening and closing of. Actuator 77
is for driving the switching valve 35 to open and close. The actuators 78 and 79 are for adjusting the valve opening pressure of WG838 or 39, that is, the maximum boost pressure.

The control details of the control unit 71- will be explained below. First, the control unit 71 controls the opening and closing of the switching valve 35 based on the map shown in FIG. This point will be explained by focusing on the map shown in FIG. 3 as follows.

First, the operating state of the engine is as shown in ■ on the right side of the β line in Figure 3.
When it is in the region, the switching valve 35 is opened (fully opened).

As a result, the turbines 22b and 2 of the 1-car supercharger 22.23
3b are both rotationally driven by receiving exhaust gas energy, and both superchargers 22 and 23 provide a second one with a large supercharging capacity.
state. At this time, the bypass valve 25 is closed and the cut valve 26 is closed.

Next, the area to the left of the α line in Figure 3 is the β line and β line.
There is a region (2) between the β line and a region (2) to the left of the β line, and in this region (2), the switching valve 35 is closed (fully open). As a result, the turbine 23b of the second supercharger 23
No exhaust gas flows into the engine, so supercharging is performed only by the first supercharger 22. At this time, both the bypass valve 25 and the cut valve 26 are closed (1).In addition, when in the region (2), the switching valve 35 is opened in the lower F, and the second supercharger 23 is opened in preparation for the situation in the region (2). is idled. At this time, the bypass valve 25 is opened and the cut valve 26 is closed.

In addition, the adjustment of the maximum boost pressure is in the area O), in case of ■, the first
By adjusting the valve opening pressure of WGB38 (control to actuator 77), and when in area ■, WGB39
By adjusting the valve opening pressure of (actuator 79
control) is carried out.

The control contents of the control unit 71 described above will be explained with reference to the flowchart shown in FIG. Note that in the following explanation, ]) indicates a step.

First, in 1) 4 of Fig. 4, the engine speed and throttle opening are read, and then in P5, the current operating state is read by applying it to the map of Fig. 3 (area ■, ■ or ■). ). And at P6,
It is determined whether or not the current area is ■, and this determination is YES.
In the case of S, 1) At 7, the switching valve 35 is fully closed (only the first supercharger 22 is operated). Also, in the judgment of P6, N
If it is O, it is determined in P8 whether or not it is in the area ■. When the determination in P8 is YES, the on-off valves 35A and 35B are fully opened in P9 (both the first and second superchargers 22 and 23 are operated). Furthermore, if the determination in P8 is No, it is area ■ after all, so
At PIO, the switching valve 35 is partially opened (the first supercharger 22 is in operation and the second supercharger 23 is idle). In addition, the bypass valve 25 and the cut valve 2 according to the operation of the switching valve 35
Since the operation of 6 is as described above, its explanation will be omitted.

Although the embodiments have been described above, the present invention is not limited thereto, and includes, for example, the following case.

■The exhaust turbo supercharger may have 3 to 7 cages.

■All exhaust turbo superchargers may be set to have the same supercharging capacity.

■If the supercharging capacities are set to be different as in the example, only the first supercharger 22 with a small supercharging capacity is operated at low speeds, and only the second supercharger 23 with a large supercharging capacity is operated at high speeds. may be activated. in this way,
If there are a plurality of superchargers that are switched between active and inactive, a switching valve may be provided in the exhaust passage downstream of the turbine of each supercharger.

(2) The supercharging capacity may be changed from low speed to high speed, for example, in three or more stages. In this case, in the embodiment, only the first supercharger 22 is operated at low speeds, only the second supercharger 23 is operated at medium speeds, and both superchargers 22 and 23 are operated at high speeds. All you have to do is let it happen.

■When only the first supercharger 22 is operating, the oil supply to the second supercharger 23 is cut off so that more sufficient oil is supplied to the first supercharger 22. You can. And preferably.

When transitioning from area ■ to area ■ or It is preferable to supply oil to the second supercharger 23 until the amount decreases. In this case, for example, the piping 5 in FIG.
9 may be provided with a cut valve, and the opening and closing of this cut valve may be controlled.

(Effects of the Invention) As is clear from the above description, the present invention allows switching between the first state where the supercharging capacity is small and the second state where the supercharging capacity is large without operating the supercharger unnecessarily. In addition, since the switching valve for performing the above switching is installed in the exhaust passage downstream of the turbine, there are fewer opportunities for high-temperature, high-pressure, and dirty exhaust gas to come into contact with this switching valve, which reduces its durability. performance is improved.

Furthermore, since high-pressure exhaust gas is always acting on the turbine of the supercharger when it is not in operation, responsiveness when the supercharger starts operating is improved.

[Brief explanation of the drawing]

FIG. 1 is an overall system diagram showing one embodiment of the present invention. FIG. 2 is a side view showing an example of the arrangement of two superchargers and their cooling water passage system and oil passage system. Figure 3 is a map showing the operating area of the supercharger. FIG. 4 is a flowchart showing a control example of the present invention.・l: Engine body 22: First supercharger (for low speed) 23: Second supercharger (for high speed) 35: Switching valve 71: Control unit 77: Actuator (for switching valve) = 1D Figure 4

Claims (1)

[Claims] (1) Equipped with multiple exhaust turbo superchargers, at low speeds only some of the superchargers are operated to achieve the first state with low supercharging capacity, while at high speeds at least the remaining superchargers are activated. In an engine supercharging device which is activated to enter a second state with a large supercharging capacity, the switching means for switching between activation and non-operation of the turbocharger is configured to control the exhaust gas downstream of the turbine of the turbocharger. A supercharging device for an engine, comprising a switching valve consisting of an on-off valve provided in a passage.