JP2005201059A - Exhaust system for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent deterioration of an exhaust emission control device or a heat energy recovery device caused by overheat, and to increase noise reduction effect. <P>SOLUTION: In an exhaust system 1, the exhaust emission control device or heat energy recovery device 8 are installed to a branch passage 7 which is branched from an exhaust passage 4, and an open/close valve 9 is disposed to the exhaust passage 4 to make exhaust gas selectively flow into either the exhaust passage 4 or branch passage 7. The branch passage 7 is branched at a upstream branch section 5 from the exhaust passage 4 through which the exhaust gas flows, and is united at a downstream branch section 6 to the exhaust passage 4. The exhaust emission control device or the heat energy recovery device 8 is disposed in the middle of the branch passage 7, the open/close valve 9 is disposed to the exhaust passage 4 between the upstream branch section 5 and downstream branch section 6, and a capacity chamber 10 communicating with the exhaust passage 4 is serially disposed in the middle of the exhaust passage 4 upstream of the upstream branch section 5. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an exhaust device for an internal combustion engine.

  An exhaust device for an internal combustion engine is provided with an exhaust purification device such as a catalytic converter for purifying exhaust gas. The exhaust purification device is installed on the upstream side of the exhaust device so as to improve the warm-up property and to purify the exhaust gas immediately after the start of the internal combustion engine. However, after warm-up, high-temperature exhaust gas circulates in the exhaust purification device, and therefore, the exhaust purification device is overheated and easily deteriorates.

  In order to solve such a problem, conventionally, an exhaust device as shown in FIG. 4 has been proposed (see FIG. 1 of Patent Document 1).

  In this exhaust device, a branch passage (catalyst passage) 104 connecting the upstream branch portion 102 and the downstream branch portion 103 provided in the exhaust passage 101 is formed, and exhaust gas is disposed in the middle of the branch passage (catalyst passage) 104. A purification device (catalyst device) 105 is provided. The exhaust passage 101 is provided with an on-off valve (switching valve) 106, which opens and closes according to the exhaust gas temperature.

  With this configuration, when the engine is cold, the on-off valve (switching valve) 106 is closed and the exhaust gas is circulated from the upstream branching portion 102 to the branch passage 104 and purified by the exhaust purification device (catalyst device) 105. Then, after warm-up, the on-off valve (switching valve) 106 is opened to allow the exhaust gas to flow through the exhaust passage 101 and bypass the exhaust purification device (catalyst device) 105. We plan to suppress the degradation of the purification device (catalyst device) 105 and improve the power performance of the vehicle.

  In addition, since the on-off valve (switching valve) 106 is provided in the middle of the exhaust passage 101, the configuration and control of the on-off valve (switching valve) 106 is easy, so that the cost is low. Are expected.

  Further, as shown in FIG. 5, by forming volume portions (chamber portions) 107 and 108 having a predetermined volume before and after the exhaust purification device (catalyst device) 105, it is caused by explosion of each cylinder of the internal combustion engine. The pressure pulse is attenuated and the exhaust gas is prevented from flowing into the branch passage (catalyst passage) 104 when the on-off valve (switching valve) 106 is in an open state, and deterioration of the exhaust purification device (catalyst device) 105 is prevented. The thing which suppresses is also known (refer FIG. 5 of patent document 1).

  However, although these volume portions (chamber portions) 107 and 108 are effective in reducing exhaust noise, they are formed before and after the exhaust purification device (catalyst device) 105, so that the on-off valve (switching valve) 106 is provided. The exhaust noise is reduced only when the valve is closed, and the exhaust noise is not reduced when the on-off valve (switching valve) 106 is open.

  Further, instead of the exhaust purification device 105, an exhaust device having a thermal energy recovery device such as a heat exchange device or a thermoelectric conversion device in the branch passage 104 is known (see Patent Document 2).

However, also in this exhaust device, the thermal energy recovery device may be overheated and deteriorated as described above.
Japanese Patent Laid-Open No. 9-317449 JP 2000-312035 A

  An object of the present invention is to provide an exhaust device for an internal combustion engine that solves the above-described problems.

  In order to solve the above-mentioned problem, the invention according to claim 1 forms a branch passage that branches from an exhaust passage through which exhaust gas circulates at an upstream branch portion and merges with the exhaust passage at a downstream branch portion. In the exhaust system for an internal combustion engine in which an exhaust purification device is provided in the middle of the branch passage, and an open / close valve is provided in the exhaust passage between the upstream branch portion and the downstream branch portion, the volume chamber communicating with the exhaust passage is provided in the upstream It is characterized by being provided in series in the middle of the exhaust passage upstream from the side branch portion.

  According to a second aspect of the present invention, a branch passage is formed that branches from an exhaust passage through which exhaust gas circulates at an upstream branch portion and merges with the exhaust passage at a downstream branch portion, and an exhaust purification device is provided in the middle of the branch passage. In the exhaust system for an internal combustion engine in which an open / close valve is provided in the exhaust passage between the upstream branch portion and the downstream branch portion, a volume chamber is provided in parallel with the exhaust passage, and the volume chamber and the upstream side A communication pipe that communicates with the exhaust passage upstream from the branching portion is provided.

  According to a third aspect of the present invention, a branch passage is formed that branches from an exhaust passage through which exhaust gas circulates at an upstream branch portion and merges with the exhaust passage at a downstream branch portion, and recovers thermal energy in the middle of the branch passage. In an exhaust system for an internal combustion engine provided with a device and provided with an on-off valve in an exhaust passage between an upstream branch portion and a downstream branch portion, an exhaust passage upstream of the upstream branch portion in a volume chamber communicating with the exhaust passage It is characterized by being provided in series in the middle.

  According to a fourth aspect of the present invention, a branch passage is formed that branches from an exhaust passage through which exhaust gas circulates at an upstream branch portion and merges with the exhaust passage at a downstream branch portion, and recovers thermal energy in the middle of the branch passage. In an exhaust system for an internal combustion engine, in which an opening / closing valve is provided in an exhaust passage between an upstream branch portion and a downstream branch portion, a volume chamber is provided in parallel with the exhaust passage, and the volume chamber and the upstream side A communication pipe that communicates with the exhaust passage upstream from the branching portion is provided.

  According to the first aspect of the present invention, since the volume portion communicating with the exhaust passage is provided in series in the middle of the exhaust passage upstream from the upstream branch portion, the pressure pulse caused by the explosion of each cylinder of the internal combustion engine. Can be attenuated. Accordingly, it is possible to suppress the exhaust gas from flowing into the branch passage side by the pressure pulse when the on-off valve is in the open state, to suppress the overheating of the exhaust purification device, and to suppress the deterioration of the exhaust purification device. Further, the silencing effect can be always obtained by the expansion action by the volume chamber, and the effect of reducing the exhaust noise can be exhibited.

  According to the second aspect of the present invention, the volume chamber is provided in parallel with the exhaust passage, and the communication pipe that communicates the volume chamber and the exhaust passage upstream of the upstream branch portion is provided. As in the case of the present invention, the effect of suppressing the deterioration of the exhaust emission control device can be exhibited. Furthermore, the volume chamber can always provide a silencing effect due to resonance, and can exhibit an effect of reducing exhaust noise.

  According to the third aspect of the present invention, due to the same action as that of the first aspect, it is possible to suppress deterioration of the thermal energy recovery device provided in the branch passage from overheating, and due to the expansion action of the volume chamber. A silencing effect can always be obtained.

  According to the fourth aspect of the present invention, due to the same action as that of the second aspect, it is possible to suppress deterioration from overheating of the thermal energy recovery device provided in the branch passage, and also due to the resonance action of the volume chamber. A silencing effect can always be obtained.

  The best mode for carrying out the present invention will be described based on the embodiment shown in FIGS.

FIG. 1 is a schematic view showing an exhaust device 1 according to a first embodiment of the present invention.
A plurality of branch pipes 3 through which exhaust gas to be discharged flows are connected to each cylinder of the internal combustion engine 2, and the branch pipes 3 are assembled and connected to a single exhaust passage 4. In the middle of the exhaust passage 4, an upstream branch portion 5 and a downstream branch portion 6 positioned downstream thereof are provided, and a branch passage 7 connecting both the branch portions 5 and 6 is provided.

  A catalytic converter 8 serving as an exhaust purification device is provided in the middle of the branch passage 7. The catalytic converter 8 contains a honeycomb-shaped carrier (not shown) carrying a noble metal and purifies harmful components in the exhaust gas, and a known one is used.

  On the other hand, an on-off valve 9 for opening and closing the exhaust passage 4 is provided in the middle of the exhaust passage 4. The on-off valve 9 detects, for example, the temperature of the catalytic converter 8 or the temperature of exhaust gas flowing into the catalytic converter 8 with a temperature sensor (not shown), and commands a control unit (not shown) according to the temperature. Therefore, the opening / closing operation may be performed by a conventionally known actuator (not shown).

  A volume chamber 10 communicating with the exhaust passage 4 is provided in series with the exhaust passage 4 in the middle of the exhaust passage 4 upstream from the upstream branching portion 5. The volume chamber 10 is formed to have a space having a larger cross-sectional area than the exhaust passage 4.

  In the above configuration, the exhaust gas discharged from each cylinder of the internal combustion engine 2 flows through each branch pipe 3, gathers downstream thereof, and flows downstream through one exhaust passage 4.

  When the air conditioner is cold, the on-off valve 9 is controlled to be in a closed state, and the exhaust gas flowing into the exhaust passage 4 flows into the branch passage 7 from the upstream branching portion 5 on the upstream side of the on-off valve 9, and is an exhaust purification device. After passing through the catalytic converter 8, the air flows again into the exhaust passage 4 on the downstream side of the on-off valve 9 through the downstream branching portion 6, and then flows downstream of the exhaust passage 4.

  When the temperature of the catalytic converter 8 reaches a predetermined temperature after warming up, the on-off valve 9 is switched to an open state by an actuator (not shown) according to the command of the control unit. When the on-off valve 9 is thus opened, the steady flow of exhaust gas does not flow into the branch passage 7 but bypasses the catalytic converter 8 and flows straight through the exhaust passage 4.

  Furthermore, since the volume chamber 10 is provided upstream of the upstream branching section 5, the volume chamber 10 can attenuate pressure pulses caused by the explosion of each cylinder of the internal combustion engine.

  Therefore, when the on-off valve 9 is in the open state, it is possible to suppress the exhaust gas from flowing into the branch passage 7 due to the pressure pulse, and to suppress overheating of the catalytic converter (exhaust gas purification device) 8. 8 can be suppressed.

  Further, since the exhaust gas always flows through the volume chamber 10 regardless of the open / close state of the on-off valve 9, it is possible to always obtain a silencing effect due to the expansion action, and to exhibit an exhaust noise reduction effect.

FIG. 2 is a schematic view showing an exhaust device according to a second embodiment of the present invention.
In the second embodiment, a volume chamber 20 is provided in parallel with the exhaust passage 4 of the first embodiment, and a communication pipe 21 that communicates the volume chamber 20 and the exhaust passage 4 upstream of the upstream branching portion 5. Is provided. The volume chamber 20 is formed so as to have a space having a larger cross-sectional area than the communication pipe 21.

  Since the other structure is the same as that of the first embodiment, the same parts as those described above are denoted by the same reference numerals and the description thereof is omitted.

  Also in the second embodiment, similarly to the first embodiment, when the on-off valve 9 is in the open state, the exhaust gas is prevented from flowing into the branch passage 7 side, and the catalytic converter (exhaust purification device) 8 Overheating can be suppressed and deterioration of the catalytic converter 8 can be suppressed.

  In the second embodiment, the exhaust gas always communicates with the volume chamber 20 regardless of the open / close state of the on-off valve 9. Therefore, a silencing effect due to the resonance action can always be obtained, and the exhaust noise reduction effect is exhibited. To do.

FIG. 3 is a schematic view showing an exhaust device according to a third embodiment of the present invention.
In the third embodiment, as shown in FIG. 3, a volume chamber 30 is provided in the middle of the exhaust passage 4, and an upstream branch portion 35 in the branch passage 7 is provided in the volume chamber 30.

  Since the other structure is the same as that of the first embodiment, the same parts as those described above are denoted by the same reference numerals and the description thereof is omitted.

  In the third embodiment, the same operation and effect as in the first embodiment are exhibited, and the exhaust noise reduction effect can be exhibited regardless of the deterioration of the exhaust purification device and the open / close state of the on-off valve 9.

  In the above embodiment, an example of a catalytic converter containing a carrier as an exhaust purification device is shown, but an exhaust purification device containing an adsorbent that adsorbs harmful components in exhaust and a filter that collects particulates in exhaust But you can.

  Further, the exhaust device can be disposed at an arbitrary position such as an engine room or a vehicle floor.

In each of the above embodiments, an exhaust device in which the catalytic converter 8 is provided as an exhaust purification device in the branch passage is shown. Instead of this exhaust purification device, heat that exchanges heat with a fluid such as cooling water in the branch passage 7 is used. Even if a thermal energy recovery device such as an exchange device or a thermoelectric conversion device equipped with a thermoelectric conversion element that converts thermal energy into electrical energy is provided, overheating of the thermal energy recovery device can be suppressed. Deterioration can be suppressed.
Therefore, when this thermal energy recovery device is installed, reference numeral 8 in FIG. 1, FIG. 2 and FIG.

The schematic diagram which shows the exhaust apparatus of 1st Example of this invention. The schematic diagram which shows the exhaust apparatus of 2nd Example of this invention. The schematic diagram which shows the exhaust apparatus of 3rd Example of this invention. The schematic diagram which shows the conventional exhaust apparatus. The schematic diagram which shows the conventional exhaust apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Exhaust device 2 Internal combustion engine 4 Exhaust passage 5,35 Upstream branch part 6 Downstream branch part 7 Branch path 8 Exhaust gas purification device, thermal energy recovery device 9 On-off valve 10, 20, 30 Volume chamber

Claims (4)

  A branch passage that branches from the exhaust passage through which the exhaust gas circulates is formed at the upstream branch portion and merges with the exhaust passage at the downstream branch portion, and an exhaust purification device is provided in the middle of the branch passage. In an exhaust system of an internal combustion engine in which an open / close valve is provided in the exhaust passage between the downstream branch portion, a volume chamber communicating with the exhaust passage is provided in series in the middle of the exhaust passage upstream from the upstream branch portion. An exhaust system for an internal combustion engine characterized by the above.   A branch passage that branches from the exhaust passage through which the exhaust gas circulates is formed at the upstream branch portion and merges with the exhaust passage at the downstream branch portion, and an exhaust purification device is provided in the middle of the branch passage. In an exhaust system of an internal combustion engine in which an open / close valve is provided in an exhaust passage between a downstream branch portion, a volume chamber is provided in parallel with the exhaust passage, and the volume chamber and an exhaust passage upstream from the upstream branch portion An exhaust system for an internal combustion engine, characterized in that a communication pipe is provided for communicating with the internal combustion engine.   A branch passage that branches from the exhaust passage through which the exhaust gas circulates is formed at the upstream branch portion and merges with the exhaust passage at the downstream branch portion, and a thermal energy recovery device is provided in the middle of the branch passage. In the exhaust system of the internal combustion engine in which an open / close valve is provided in the exhaust passage between the upstream branch portion and the downstream branch portion, a volume chamber communicating with the exhaust passage is provided in series in the middle of the exhaust passage upstream from the upstream branch portion. An exhaust system for an internal combustion engine.   A branch passage that branches from the exhaust passage through which the exhaust gas circulates is formed at the upstream branch portion and merges with the exhaust passage at the downstream branch portion, and a thermal energy recovery device is provided in the middle of the branch passage. In the exhaust system of the internal combustion engine in which an open / close valve is provided in the exhaust passage between the downstream branch portion and the downstream branch portion, a volume chamber is provided in parallel with the exhaust passage, and the exhaust passage upstream of the volume chamber and the upstream branch portion is provided. An exhaust system for an internal combustion engine, characterized in that a communication pipe is provided for communicating with the internal combustion engine.

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