JPH074839U - Exhaust device for sequential turbo engine - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the vibration force of the exhaust control valve and reduce noise and spring load. [Configuration] A primary turbo supercharger 5 and a secondary turbo supercharger 6 are connected to the exhaust manifolds 20 and 21 of the left and right banks 3 and 4 of the engine body 1, respectively, and the exhaust manifolds 20 and 21 are connected by a communication pipe 22. Is
The exhaust control valve 3 is provided on the exhaust inflow side of the secondary turbocharger 6.
1 is provided so that it can be opened and closed. Then, between the exhaust control valve 31 of the exhaust manifold 21 to the secondary turbocharger 6 and the turbine upstream side of the exhaust manifold 20 to the primary turbocharger 5, the resonance prevention chamber 41 is provided.
The pulsation pressure relief pipe 40 having the above is communicated so as to release and reduce the exhaust pulsation pressure of the left and right banks 3 and 4.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an exhaust device for a sequential turbo engine equipped with a plurality of turbochargers in a vehicle, and more particularly to noise reduction measures for an exhaust control valve.

[0002]

[Prior art]

 In recent years, a sequential turbo engine has been proposed as a supercharged engine for vehicles. This engine has a multi-cylinder exhaust system in which a primary turbocharger and a secondary turbocharger are installed in parallel.For example, in a single turbo mode in the low speed range, only the primary turbocharger operates and in the high speed range When in the twin turbo mode, both turbochargers are activated to obtain the optimum engine output characteristics according to the running condition. Therefore, the exhaust system of the engine is required to be configured so that both the primary turbocharger and the secondary turbocharger operate well.

Conventionally, as for the above-mentioned sequential turbo engine, there is a prior art disclosed in, for example, Japanese Patent Laid-Open No. 14-8028. In this prior art, the exhaust manifolds of the first supercharger and the second supercharger, which are arranged in parallel to the exhaust system of the engine, are connected to each other by a connecting pipe to connect the connecting pipe and the second supercharger. An exhaust switching valve is provided at the branch. Then, the exhaust gas switching valve closes the second supercharger side and opens the communication pipe, and introduces the exhaust gas of all cylinders of the engine to the first supercharger. Further, it is shown that the exhaust switching valve opens the second supercharger side and closes the communication pipe, and the exhaust gases of the left and right cylinders are independently introduced into the first and second superchargers.

[0004]

[Problems to be solved by the device]

 By the way, in the above-mentioned prior art, the exhaust manifolds of the first supercharger and the second supercharger are simply connected by a connecting pipe. For this reason, in the single turbo mode in which only the first supercharger is operated, a closed exhaust switching valve causes a dead end, and therefore, when exhausting a cylinder close to the exhaust switching valve, the broken line in FIG. The large exhaust pulsation pressure acts as follows. Then, the exhaust pulsation pressure excites the exhaust switching valve to generate noise such as chattering. Further, when the exhaust switching valve is opened downstream, there is a problem that the load of the return spring increases.

In view of such a point, the present invention aims to reduce the vibration force of the exhaust control valve to reduce noise, spring load, and the like.

[0006]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention has a primary turbocharger and a secondary turbocharger connected to the exhaust manifolds of the left and right banks of the engine body, respectively, and the exhaust manifolds are connected by a communication pipe, and a secondary turbocharger is connected. In a sequential turbo engine with an exhaust control valve that can be opened and closed on the exhaust gas inflow side of the supercharger, immediately before the exhaust control valve of the exhaust manifold to the secondary turbocharger and to the primary turbocharger. A pulsation pressure relief pipe is connected between the manifold and the upstream side of the turbine so as to communicate with the left and right banks so as to release and reduce the exhaust pulsation pressure.

[0007]

[Action]

 In the present invention having the above-mentioned configuration, when the exhaust control valve is controlled to close in the low speed range during engine operation, all of the exhaust gas from the left and right banks is introduced into the primary turbocharger through the exhaust manifold and the communication pipe. It operates in single turbo mode. At this time, when exhausting the cylinder of the right bank, the exhaust pulsation pressure acts on the closed exhaust control valve, but the exhaust pulsation pressure smoothly escapes to the pulsation pressure relief pipe immediately before the exhaust control valve and is suitable. As a result, the vibration control force of the exhaust control valve is reduced and chattering etc. does not occur.

[0008]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. Referring to FIG. 1, a case of a 4-cylinder horizontal opposed type sequential turbo engine will be described. In the engine body 1, banks 3 and 4 having cylinder heads are horizontally arranged on the left and right of a crankcase 2, the right bank 4 has first and third cylinders, and the left bank 3 has second and fourth cylinders. Cylinders are arranged and operated in the ignition order of # 1 → # 3 → # 2 → # 4. Immediately after the left and right banks 3 and 4, a primary turbo supercharger 5 and a secondary turbo supercharger 6 are arranged respectively.

As an intake system, intake pipes 10 and 11 branched from the air cleaner 19 are connected to the blowers 5b and 6b of the turbochargers 5 and 6 respectively, and the intake pipes from the blowers 5b and 6b are connected to each other. 12, 13 are communicated with the intercooler 14. The intercooler 14 communicates with a chamber 16 via a throttle valve 15, and the chamber 16 communicates with each cylinder of the left and right banks 3 and 4 via intake manifolds 17 and 18.

As an exhaust system, exhaust manifolds 20 and 21 are taken out from the lower portions of the left and right banks 3 and 4, respectively, and these exhaust manifolds 20 and 21 are connected to each other by a communication pipe 22. One exhaust manifold 20 is communicated with the turbine 5a of the primary turbocharger 5, the other exhaust manifold 21 is communicated with the turbine 6a of the secondary turbocharger 6, and the exhaust pipe 25 from both turbines 5a, 6a is one. It merges with the main exhaust pipe 26 and communicates with the catalytic converter 27 and the muffler 28.

The primary turbocharger 5 is provided with a waste gate valve 30 which is communicated with the exhaust manifold 20 so as to be constantly supercharged and bypasses the turbine 5 a to control the supercharging pressure. The secondary turbocharger 6 is provided with an exhaust control valve 31 that opens downstream in an exhaust manifold 21 on the turbine inlet side so as to be openable and closable, and an intake control valve 32 is provided in an intake pipe 13 below the blower 6b. A supercharging pressure relief valve 33 is provided between the upper side and the lower side of 6b, and a waste gate valve 34 is separately provided on the turbine side. In the single turbo mode in the low speed range, the exhaust control valve 31 and the intake control valve 32 are closed by the actuators 31a and 32a, and the boost pressure relief valve 33 is opened by the actuator 33a. In the twin turbo mode in the high speed range, those valves are closed. It is controlled so that the open / closed states of 31 to 33 are reversed.

A description will be given of a measure for reducing noise and the like of the exhaust control valve 31 in the single turbo mode in the above configuration. When the exhaust control valve 31 is closed in the single turbo mode, one end of the exhaust system becomes a dead end at the exhaust control valve 31, so only the exhaust pulsation pressure needs to be released immediately before the exhaust control valve 31. Therefore, the pulsation pressure relief pipe 40 is connected between the exhaust control valve 31 of the exhaust manifold 21 of the secondary turbocharger 6 and the upstream side of the turbine of the exhaust manifold 20 of the primary turbocharger 5. The pulsation pressure relief pipe 40 is formed to have a length and a thickness suitable for reducing the exhaust pulsation pressure of the left and right banks 3 and 4. A resonance preventing chamber 41 is provided at both ends of the pulsation pressure relief pipe 40 to prevent resonance of the exhaust pulsation pressures of the left and right banks 3 and 4 due to the interference of the exhaust pulsation pressures.

Next, the operation of this embodiment will be described. First, in the low speed range during engine operation, the exhaust control valve 31 and the intake control valve 32 are closed and the boost pressure relief valve 33 is controlled to open, so that the exhaust control valve 31 controls the secondary turbocharger 6 to operate. The introduction of exhaust gas into is cut. Therefore, the exhaust gases discharged from the left and right banks 3 and 4 of the engine body 1 are gathered together by the exhaust manifolds 20 and 21 and the communication pipe 22 and introduced into only the turbine 5a of the primary turbocharger 5.

At this time, the exhaust gas is also introduced into the pulsation pressure relief pipe 40 communicating with the exhaust manifold 21, but the pulsation pressure relief pipe 40 is introduced into the pulsation pressure relief pipe 40 alternately from both ends depending on the ignition order, so that the exhaust gas is blocked in the pulsation pressure relief pipe 40. Therefore, the flow of exhaust gas through the pulsation pressure relief pipe 40 is not actually performed. Therefore, the exhaust gases of the left and right banks 3 and 4 flow smoothly by being guided only by the original exhaust manifolds 20 and 21 and the communication pipe 22, and thus, the single turbo mode in which only the primary turbocharger 5 is operated. Then, the blower 5b is rotationally driven together with the turbine 5a of the primary turbocharger 5, and the air is compressed and supplied to the intake pipe 12 and thereafter, thereby improving the air charging efficiency and increasing the output in the low speed range.

On the other hand, in the horizontally opposed engine, since the ignition order is determined as described above, the first bank and the third cylinder of the right bank 4 continuously exhaust the gas twice, and then the second bank of the left bank 3 and the second cylinder. The exhaust of the four cylinders is repeated twice in a row. When exhausting the first and third cylinders of the right bank 4, the exhaust pulsation pressure P acts on the exhaust control valve 31 closed via the exhaust manifold 21, but the exhaust control valve 31 Immediately before, the pulsating pressure relief pipe 40 is smoothly released. Here, the pulsation pressure relief pipe 40 is prevented from resonating due to the interference of the exhaust pulsation pressures by the resonance prevention chamber 41, so that the exhaust pulsation pressure P of the pulsation pressure relief pipe 40 is appropriately determined in the process of being transmitted through the pipe. Is reduced to. Therefore, the exhaust pulsation pressure P does not act much on the closed exhaust control valve 31, and the vibration force is reduced as shown by the solid line in FIG. Further, also during exhaust of the second and fourth cylinders of the left bank 3, the exhaust pulsation pressure thereof escapes to the pulsation pressure relief pipe 40 and is reduced.

Next, in the middle and high speed ranges, the exhaust control valve 31 is opened, so that the exhaust gases of the left and right banks 3 and 4 are introduced into the primary turbo supercharger 5 and the secondary turbo supercharger 6 to operate. , Twin turbo mode is set. Also in this mode, the pulsation pressure relief pipe 40 is clogged with exhaust gas, and the exhaust pulsation pressure during exhaust of the left and right banks 3 and 4 is similarly reduced.

Although the embodiment of the present invention has been described above, the invention can be similarly applied to a sequential turbo engine other than the horizontally opposed type.

[0018]

[Effect of device]

 As described above, according to the present invention, in a sequential turbo engine equipped with a plurality of turbochargers, a pulsating pressure relief pipe is provided immediately before the exhaust control valve of the secondary turbocharger and between the primary turbocharger. Are connected in series to reduce the exhaust pulsation pressure when exhausting the left and right banks, so that the excitation force can be effectively reduced especially when the exhaust control valve is closed in the single turbo mode. it can. Therefore, noise such as chattering of the exhaust control valve is reduced, and the spring load on the actuator of the exhaust control valve can be reduced even when the exhaust valve is opened downstream. In addition, the exhaust pulsation pressure in the left and right banks is constantly reduced, which reduces engine noise and smoothens turbo turbocharger operation. Since the pulsation pressure relief pipe is provided with the resonance prevention chamber, resonance due to interference between the exhaust pulsation pressures is prevented, and the exhaust pulsation pressure can be appropriately reduced.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of an exhaust device for a sequential turbo engine according to the present invention.

FIG. 2 is a pressure waveform diagram showing an exciting force of an exhaust control valve.

[Explanation of symbols]

 1 Engine Main Body 3, 4 Left and Right Bank 5 Primary Turbocharger 6 Secondary Turbocharger 20, 21 Exhaust Manifold 22 Communication Pipe 31 Exhaust Control Valve 40 Pulsating Pressure Relief Pipe 41 Resonance Prevention Chamber

Claims (2)

[Scope of utility model registration request] 1. A primary turbo supercharger and a secondary turbo supercharger are respectively connected to the exhaust manifolds of the left and right banks of the engine body, and the exhaust manifolds are connected by a communication pipe, and the exhaust inflow side of the secondary turbocharger is connected. In a sequential turbo engine in which the exhaust control valve is openable and closable, the pulsation occurs immediately before the exhaust control valve of the exhaust manifold to the secondary turbocharger and the turbine upstream side of the exhaust manifold to the primary turbocharger. An exhaust system for a sequential turbo engine, wherein pressure relief pipes are connected so as to release and reduce exhaust pulsation pressure in the left and right banks. 2. The exhaust system for a sequential turbo engine according to claim 1, wherein the pulsation pressure relief pipe has a resonance prevention chamber in the middle thereof.