JP2008095534A - Internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suitably control a bank by preventing heat damage caused by a communicating pipe and by reducing a size of a device. <P>SOLUTION: In a V-type six-cylinder engine, a cylinder group wherein a plurality of cylinders are divided to left and right first and second banks 12 and 13 is provided, an intake pipe 51 is connected to the cylinder group of the banks 12 and 13, a first exhaust pipe 57 and a second exhaust pipe 58 are connected, a first front stage three-dimensional catalyst 59 and a second front stage three-dimensional catalyst 60 are respectively disposed on the exhaust pipes 57 and 58, and a first control valve 64 and a second control valve 65 are disposed, and the front stage three-dimensional catalysts 59 and 60 of the exhaust pipes 57 and 58 and the upstream sides of the control valves 64 and 65 are communicated through the communicating pipe 63, and collecting passages 55 and 56 communicating with exhaust ports 26 and 27 and exhaust pipe connection parts 55a and 56 and communicating pipe connection parts 55b and 56b are integrally formed in cylinder heads 20 and 21 in the left and right banks 12 and 13. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an internal combustion engine having two cylinder groups in which a plurality of cylinders are divided into left and right banks and in which the upstream side of the exhaust passage of each cylinder group is communicated by a communication passage.

  In a general V-type multi-cylinder engine, a cylinder block has two banks inclined upward at a predetermined angle, and a plurality of cylinders are provided in each bank to constitute two cylinder groups. Pistons are movably fitted to a plurality of cylinders provided in each bank, and each piston is connected to a crankshaft that is rotatably supported at the lower part. In addition, each combustion chamber is configured by fastening a cylinder head to the upper part of each bank of the cylinder block, and each combustion chamber is formed with an intake port and an exhaust port, and can be opened and closed by an intake valve and an exhaust valve. It has become. An intake pipe is connected to the intake port of each bank, while an exhaust pipe is connected to the exhaust port of each bank. A front-stage purification catalyst is attached to the exhaust pipe, and an exhaust collecting pipe into which the exhaust pipes merge is connected. A post-stage purification catalyst is installed.

  In such a V-type multi-cylinder engine, in order to warm up the early stage purification catalyst at the time of low temperature start of the engine and to activate it early, the two exhaust pipes communicate with each other on the upstream side of the previous stage purification catalyst. Some bank control is enabled by providing a control valve in each exhaust pipe. Therefore, when the engine is started at a low temperature, the control valve of one exhaust pipe is closed and the exhaust gas from the cylinder group of each bank is merged in the other exhaust pipe through the communication pipe. It is possible to warm up the purification catalyst efficiently and achieve early activation.

  In addition, there is such a V-type multi-cylinder engine in which a turbocharger is provided only in one bank. In this case, when the turbocharger is in operation, the control valve of the exhaust pipe without the turbocharger is closed and the exhaust gas from the cylinder group of each bank is merged through the communication pipe in the exhaust pipe with the turbocharger. After that, the turbocharger turbine is driven by this large amount of exhaust gas, the compressor integrated with this turbine is driven to compress the air, and the turbocharger is introduced into the combustion chamber. Thermal deterioration of the upstream purification catalyst on the exhaust pipe side without the supercharger can be suppressed.

  As such an internal combustion engine, there is an “exhaust gas purification device for an internal combustion engine” described in Patent Document 1 below.

Japanese Patent Laid-Open No. 08-121153

  In the conventional engine described above, the control valve provided in the exhaust pipe of one bank is closed in accordance with the operating state of the engine, and the exhaust gas discharged from the cylinder group of this one bank is exhausted to the other exhaust through the communication pipe. By flowing through the pipe, the exhaust gas discharged from the cylinder group of the other bank is merged, and the pre-purification catalyst is warmed up or the turbocharger is driven by the merged exhaust gas.

  In this case, the exhaust pipes connected to the cylinder groups of the left and right banks are connected by a communication pipe on the rear side of the engine. Since various auxiliary machines are arranged behind the engine, when exhaust gas passes through the communication pipe, the communication pipe becomes hot due to the heat of the exhaust gas, and various auxiliary machines around the communication pipe. May be damaged by heat. Therefore, in order to prevent heat damage from the communication pipe, it is possible to install a heat insulating material around the communication pipe or increase the distance between the communication pipe and various auxiliary equipment, but this increases the cost and design. There is a problem that the degree of freedom is lost and the mountability deteriorates.

  The present invention is intended to solve such a problem, and provides an internal combustion engine capable of good bank control by preventing thermal damage caused by a communication pipe and reducing the size of the apparatus. With the goal.

  In order to solve the above-described problems and achieve the object, an internal combustion engine of the present invention has two cylinder groups in which a plurality of cylinders are divided into left and right banks, and intake air is supplied to each cylinder group. While the passages are provided, the exhaust passages are provided independently, a control valve for adjusting the flow rate of the exhaust gas is provided in each exhaust passage, and a purification catalyst is provided in at least one of the exhaust passages. In the internal combustion engine in which the upstream side of each control valve and the purification catalyst in each exhaust passage is communicated by a communication passage, the exhaust passage is connected to the cylinder group in at least one of the left and right banks. The cylinder head has a collecting passage for collecting exhaust gas to be discharged, and a connecting portion of the collecting passage and the communication passage to the collecting passage is provided in the cylinder head.

  In the internal combustion engine of the present invention, a supercharger is provided in the other exhaust passage of the left and right banks, and the communication passage is connected to the inlet side of the supercharger in the exhaust passage.

  In the internal combustion engine of the present invention, the exhaust passages in the left and right banks each have a collecting passage in which exhaust gas discharged from the cylinder group collects, and the connecting portion of the connecting passage to the collecting passage and the collecting passage Is provided in the cylinder head, and the connecting portion is opened on the opposing surface of each cylinder head in the left and right banks, and is connected by a communication pipe.

  The internal combustion engine of the present invention is characterized in that a heat exchanger capable of exchanging heat between the exhaust gas and the cooling medium is provided in the communication passage.

  The internal combustion engine of the present invention is characterized in that the amount of heat exchange between the exhaust gas and the cooling medium by the heat exchanger is changed by opening and closing the control valve according to the operating state.

  In the internal combustion engine of the present invention, the heat exchanger is connected to a heater unit.

  According to the internal combustion engine of the present invention, there are two cylinder groups in which a plurality of cylinders are divided into left and right banks, and an exhaust passage is provided independently for each cylinder group. An exhaust control valve for adjusting the gas flow rate is provided and a purification catalyst is provided, and each control valve in each exhaust passage and the upstream side of the purification catalyst are connected by a communication passage, and at least one of the left and right banks The exhaust passage is provided with a collecting passage for collecting exhaust gas discharged from the cylinder group, and the connecting portion of the collecting passage and the communication passage for the collecting passage is provided in the cylinder head. By opening and closing the control valve provided in the exhaust passage, the exhaust gas discharged from the cylinder group of one bank flows through the communication pipe to the other exhaust pipe and is discharged from the cylinder group of the other bank. When the bank control for processing by joining with the exhaust gas is performed, the connecting portion of the collecting passage and the communication passage is provided in the cylinder head, so that the length of the communication pipe exposed to the outside is shortened. In addition to preventing heat damage due to the communication pipe, it is possible to prevent the temperature of the exhaust gas flowing through the communication pipe from being lowered, and as a result, it is possible to achieve good bank control and the compactness of the apparatus. Can be achieved.

  Embodiments of an internal combustion engine according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited by this Example.

  FIG. 1 is a schematic plan view of a V-type 6-cylinder engine representing an internal combustion engine according to Embodiment 1 of the present invention, and FIG. 2 is a schematic cross-sectional view of the V-type 6-cylinder engine of Embodiment 1.

  In the first embodiment, a V-type 6-cylinder engine is applied as the internal combustion engine. In this V-type six-cylinder engine, as shown in FIGS. 1 and 2, the cylinder block 11 has left and right banks 12 and 13 inclined at a predetermined angle at the upper portion, and a plurality of cylinders are provided in each bank 12 and 13. Are provided to form two cylinder groups. Each of the banks 12 and 13 is formed with three cylinder bores 14 and 15, and pistons 16 and 17 are fitted to the cylinder bores 14 and 15 so as to be vertically movable. A crankshaft (not shown) is rotatably supported at the lower part of the cylinder block 11, and the pistons 16 and 17 are connected to the crankshaft via connecting rods 18 and 19, respectively.

  On the other hand, cylinder heads 20 and 21 are fastened to the upper portions of the banks 12 and 13 of the cylinder block 11, and the combustion chambers 22 and 23 are constituted by the cylinder block 11, the pistons 16 and 17, and the cylinder heads 20 and 21. ing. The intake ports 24 and 25 and the exhaust ports 26 and 27 are formed on the upper portions of the combustion chambers 22 and 23, that is, the lower surfaces of the cylinder heads 20 and 21 so as to face each other. 27, the lower end portions of the intake valves 28 and 29 and the exhaust valves 30 and 31 are located. The intake valves 28 and 29 and the exhaust valves 30 and 31 are supported by the cylinder heads 20 and 21 so as to be movable in the axial direction, and are attached in a direction to close the intake ports 24 and 25 and the exhaust ports 26 and 27. It is supported. Further, intake camshafts 32 and 33 and exhaust camshafts 34 and 35 are rotatably supported on the cylinder heads 20 and 21, and the intake cams 36 and 37 and the exhaust cams 38 and 39 are interposed via a roller rocker arm (not shown). Are in contact with the upper ends of the intake valves 28 and 29 and the exhaust valves 30 and 31.

  Accordingly, when the intake camshafts 32 and 33 and the exhaust camshafts 34 and 35 rotate in synchronization with the engine, the intake cams 36 and 37 and the exhaust cams 38 and 39 operate the roller rocker arm, and the intake valves 28 and 29 and the exhaust valve 30 and 31 move up and down at a predetermined timing to open and close intake ports 24 and 25 and exhaust ports 26 and 27, intake ports 24 and 25 and combustion chambers 22 and 23, combustion chambers 22 and 23, and exhaust port 26. , 27 can communicate with each other.

  In addition, the valve mechanism of this engine is a variable intake valve timing mechanism (VVT) 40 that controls the intake valves 28 and 29 and the exhaust valves 30 and 31 at an optimal opening / closing timing according to the operating state. 41 and an exhaust variable valve mechanism 42, 43. The intake variable valve operating mechanisms 40 and 41 and the exhaust variable valve operating mechanisms 42 and 43 are configured, for example, by providing VVT controllers at the shaft end portions of the intake camshafts 32 and 33 and the exhaust camshafts 34 and 35. The opening / closing timing of the intake valves 28, 29 and the exhaust valves 30, 31 is advanced or retarded by changing the phase of each camshaft 32, 33, 34, 35 with respect to the cam sprocket by a pump (or electric motor). Is something that can be done. In this case, each variable valve mechanism 40, 41, 42, 43 advances or retards the opening / closing timing with the operating angle (opening period) of intake valves 28, 29 and exhaust valves 30, 31 being constant. The intake camshafts 32, 33 and the exhaust camshafts 34, 35 are provided with cam position sensors 44, 45, 46, 47 for detecting their rotational phases.

  A surge tank 50 is connected to the intake ports 24 and 25 of the cylinder heads 20 and 21 via intake manifolds 48 and 49. On the other hand, an air cleaner 52 is attached to an air intake port of an intake pipe (intake passage) 51, and an electronic throttle device 54 having a throttle valve 53 is provided in the intake pipe 51 and is located downstream of the air cleaner 52. It has been. The downstream end of the intake pipe 51 is connected to the surge tank 50.

  The exhaust ports 26 and 27 communicate with collecting passages 55 and 56 in which exhaust gases discharged from the combustion chambers 22 and 23 gather, and exhaust pipe connecting portions 55a and 56a are connected to the collecting passages 55 and 56, respectively. The first and second exhaust pipes 57 and 58 are connected to each other. In this case, the exhaust ports 26 and 27, the collecting passages 55 and 56, and the exhaust pipe connecting portions 55a and 56a are integrally formed in the cylinder heads 20 and 21 of the left and right banks 12 and 13, respectively.

  A first front three-way catalyst (purification catalyst) 59 is attached to the first exhaust pipe 57, while a second front three-way catalyst (purification catalyst) 60 is attached to the second exhaust pipe 58. The downstream end portions of the first and second exhaust pipes 57 and 58 are joined and connected to the exhaust collecting pipe 61, and the NOx occlusion reduction type catalyst 62 is attached to the exhaust collecting pipe 61. Each of the preceding three-way catalysts 59 and 60 simultaneously purifies HC, CO, and NOx contained in the exhaust gas by an oxidation-reduction reaction when the exhaust air-fuel ratio is stoichiometric. The NOx occlusion reduction type catalyst 62 temporarily occludes NOx contained in the exhaust gas when the exhaust air-fuel ratio is lean, and occludes when it is in the rich combustion region or stoichiometric combustion region where the oxygen concentration in the exhaust gas is reduced. The released NOx is released, and NOx is reduced by the added fuel as a reducing agent.

  Further, the upstream side of the first exhaust pipe 57 and the second exhaust pipe 58 is connected by a communication pipe (communication path) 63 on the upstream side in the flow direction of the exhaust gas from the position where the front three-way catalysts 59 and 60 are mounted. It is communicated. Specifically, the cylinder heads 20, 21 of the left and right banks 12, 13 are formed with communication pipe connection portions 55 b, 56 b that communicate with the collecting passages 55, 56, and each end of the communication pipe 63. Are connected to the communication pipe connecting portions 55b and 56b. In this case, in addition to the exhaust ports 26 and 27, the collecting passages 55 and 56, and the exhaust pipe connection portions 55a and 56a, communication pipe connection portions 55b and 56b are formed integrally with the cylinder heads 20 and 21, respectively. That is, the exhaust pipe connection portions 55a and 56a are opened on the side surfaces of the left and right banks 12 and 13 where the cylinder heads 20 and 21 do not face each other, and the communication pipe connection portions 55b and 56 are formed on the rear surfaces of the cylinder heads 20 and 21, respectively. Is open.

  A first control valve 64 and a second control valve 65 are mounted on the first exhaust pipe 57 and the second exhaust pipe 58 on the downstream side of the upstream three-way catalyst 59, 60 in the flow direction of the exhaust gas. Yes. The first and second control valves 64 and 65 are flow control valves, and the flow rate of the exhaust gas flowing through the exhaust pipes 57 and 58 can be adjusted by adjusting the opening degree.

  A turbocharger 67 is provided on the first bank 12 side. The turbocharger 67 is configured such that a compressor 68 provided on the intake pipe 51 side and a turbine 69 provided on the first exhaust pipe 57 side are integrally connected by a connecting shaft 70. In this case, the turbocharger 67 can drive the turbine 69 by the exhaust gas from the first exhaust pipe 57 on the first bank 12 side, and the end of the communication pipe 63 is connected to the turbine 69 in the first exhaust pipe 57. It is connected upstream from the mounting portion. In the turbocharger 67, downstream of the compressor 68 and upstream of the electronic throttle device 54 (throttle valve 53), intake air that has been compressed by the compressor 68 and has risen in temperature is supplied to the intake pipe 51. An intercooler 71 for cooling is provided.

  Therefore, the turbocharger 67 provided in the first bank 12 is turbine-driven by the exhaust gas discharged from the combustion chamber 22 of the first bank 12 through the exhaust port 26 and the collecting passage 55 to the first exhaust pipe 57. 69 is driven, and the compressor 68 connected by the connecting shaft 70 is driven, so that the air flowing through the intake pipe 51 can be compressed. Therefore, the air introduced from the air cleaner 52 into the intake pipe 51 becomes compressed intake air and is cooled by the intercooler 71 and then introduced into the surge tank 50, and the intake manifolds 48 and 49 and the intake ports of the banks 12 and 13. The air is sucked into the combustion chambers 22 and 23 through 24 and 25.

  The cylinder heads 20 and 21 are respectively equipped with injectors 72 and 73 for injecting fuel (gasoline) directly into the combustion chambers 22 and 23. Delivery pipes 74 and 75 are connected to the injectors 72 and 73, respectively. Each of the delivery pipes 74 and 75 can be supplied with fuel at a predetermined pressure from a high-pressure fuel pump 76. The cylinder heads 20 and 21 are provided with spark plugs 77 and 78 that are located above the combustion chambers 22 and 23 and ignite the air-fuel mixture.

  Incidentally, an electronic control unit (ECU) 79 is mounted on the vehicle, and this ECU 79 can control the fuel injection timing of the injectors 72 and 73, the ignition timing of the spark plugs 77 and 78, and the like. The fuel injection amount, the injection timing, the ignition timing, and the like are determined based on the engine operating conditions such as the intake air amount, intake air temperature, throttle opening, accelerator opening, engine speed, and coolant temperature. That is, the air flow sensor 80 and the intake air temperature sensor 81 are mounted on the upstream side of the intake pipe 51, and the measured intake air amount and intake air temperature are output to the ECU 79. The electronic throttle device 54 is provided with a throttle position sensor 82, and the accelerator pedal is provided with an accelerator position sensor 83, which outputs the current throttle opening and accelerator opening to the ECU 79. Further, a crank angle sensor 84 is provided on the crankshaft, and the detected crank angle is output to the ECU 79. The ECU 79 calculates the engine speed based on the crank angle. Further, the cylinder block 11 is provided with a water temperature sensor 85 and outputs the detected engine cooling water temperature to the ECU 79.

  Further, the ECU 79 can control the intake variable valve mechanisms 40 and 41 and the exhaust variable valve mechanisms 42 and 43 based on the engine operating state. That is, when the temperature is low, the engine is started, the engine is idling, or when the load is light, the exhaust gas 30 is exhausted from the intake port 24, 31 by eliminating the overlap between the exhaust valve 30, 31 opening timing and the intake valve 28, 29 opening timing. 25 or the amount of air blown back to the combustion chambers 22 and 23 is reduced, and combustion stability and fuel efficiency can be improved. Further, at the time of medium load, by increasing the overlap, the internal EGR rate is increased to improve the exhaust gas purification efficiency, and the pumping loss is reduced to improve the fuel consumption. Further, at the time of high-load low-medium rotation, the closing timing of the intake valves 28 and 29 is advanced to reduce the amount of intake air that blows back to the intake ports 24 and 25, thereby improving volumetric efficiency. At the time of high load and high rotation, the closing timing of the intake valves 28 and 29 is retarded according to the rotational speed, thereby improving the volume efficiency as the timing according to the inertial force of the intake air.

  In the V-type 6-cylinder engine of this embodiment, as described above, the first exhaust pipe 57 and the second exhaust pipe 58 are connected to the collecting passages 55 and 56 of the cylinder heads 20 and 21, respectively. First and second front three-way catalysts 59 and 60 and first and second control valves 64 and 65 are mounted on the exhaust pipe 57 and the second exhaust pipe 58, and the collecting passages 55 and 56 are connected to the communication pipe 63. It is communicated by. Therefore, various bank control is possible by changing the combustion state of each bank 12 and 13 and the exhaust gas discharge route.

  When the engine is started at a low temperature, for example, the first control valve 64 is closed and the second control valve 65 is opened, and the first exhaust pipe 57 is connected from the cylinder group of the first bank 12 to the first exhaust pipe 57 via the collecting passage 55. By bypassing the discharged exhaust gas to the second exhaust pipe 58 through the communication pipe 63, exhaust gas from the cylinder groups of the first and second banks 12 and 13 is merged in the second exhaust pipe 58, and then a large amount This exhaust gas is caused to flow into the second front-stage three-way catalyst 60, so that the second front-stage three-way catalyst 60 is warmed up. Thereafter, when the warming-up of the second pre-stage three-way catalyst 60 is completed and activated, the first and second control valves 64 and 65 are opened, and exhaust gases from the cylinder groups of the banks 12 and 13 are discharged. Instead of passing through the communication pipe 63, the exhaust gas collecting pipe 61 is joined through the exhaust pipes 57 and 58, and then the exhaust gas is flowed into the NOx occlusion reduction type catalyst 62 to be purified.

  Further, in the V-type 6-cylinder engine of this embodiment, in a high load state, the first control valve 64 is opened, while the second control valve 65 is closed, and the second bank 13 cylinder group is removed. By exhausting the exhaust gas discharged to the second exhaust pipe 58 via the collecting passage 56 to the first exhaust pipe 57 through the communication pipe 63, the exhaust gas from the cylinder groups of the first and second banks 12 and 13 is made to flow. After merging in the first exhaust pipe 57, a large amount of exhaust gas is caused to flow into the turbocharger 67, whereby the turbocharger 67 can be operated with high efficiency and high turbocharging can be achieved. The thermal deterioration of the second front three-way catalyst 60 attached to the second exhaust pipe 58 of the cylinder group of the second bank 13 that does not have the supercharger is suppressed.

  Further, for example, the exhaust gas from the cylinder group of the first bank 12 has a lean atmosphere, the exhaust gas from the cylinder group of the second bank 13 has a rich atmosphere, and the first control valve 64 and the second control valve 65 are The exhaust gas in the lean atmosphere discharged from the cylinder group of the first bank 12 is made to flow into the first exhaust pipe 57, and the exhaust gas in the rich atmosphere discharged from the cylinder group of the second bank 13 is made into the first exhaust pipe. The NOx occlusion reduction type catalyst 62 is warmed up using the oxidation exothermic reaction in the NOx occlusion reduction type catalyst 62 or accumulated in the NOx occlusion reduction type catalyst 62. The sulfur component is released and regenerated.

  However, since various auxiliary machines are arranged around the engine, when the bank control for opening and closing the control valves 64 and 65 according to the operating state of the engine is executed, the exhaust gas is exhausted in the communication pipe 63. When the gas passes, the communication pipe 63 becomes hot due to the heat of the exhaust gas, and various auxiliary equipments around the communication pipe 63 may be damaged by heat damage.

  Therefore, in the engine of the first embodiment, as described above, the exhaust ports 26 and 27, the collecting passages 55 and 56, the exhaust pipe connecting portions 55a and 56a, and the exhaust ports 26 and 27 are provided in the cylinder heads 20 and 21 in the left and right banks 12 and 13, respectively. The communication pipe connecting portions 55b and 56b are integrally formed. Therefore, by shortening the length of the communication pipe 63 exposed to the outside, it is possible to prevent heat damage caused by the communication pipe 63 and to prevent a temperature drop of the exhaust gas flowing through the communication pipe 63. .

  Here, the opening / closing control of the control valves 64 and 65 in the V-type 6-cylinder engine of the first embodiment will be described.

  In the V-type 6-cylinder engine of the first embodiment, the air introduced into the intake pipe 51 through the air cleaner 52 is compressed by the compressor 68 of the turbocharger 67 provided on the first bank 12 side, After being metered by the throttle valve 53, it flows into the surge tank 50, reaches the intake ports 24, 25 via the intake manifolds 48, 49, and opens the intake ports 24, 25 when the intake valves 28, 29 are opened. Air is drawn into the combustion chambers 22,23. During this intake stroke or during the compression stroke in which the pistons 16 and 17 rise and compress the intake air, the injectors 72 and 73 inject a predetermined amount of fuel into the combustion chambers 22 and 23. Then, high-pressure air and mist-like fuel are mixed in the combustion chambers 22 and 23, and the ignition plugs 77 and 78 are ignited and explode in the air-fuel mixture, whereby the pistons 16 and 17 are pushed down. While the driving force is output, when the exhaust valves 30 and 31 are opened, the exhaust gas in the combustion chambers 22 and 23 is collected from the exhaust ports 26 and 27 through the collecting passages 55 and 56 and then the first exhaust pipe 57 and the second exhaust pipe. It is discharged to the tube 58. The exhaust gas discharged to the first exhaust pipe 57 drives the turbine 69 of the turbocharger 67, and the compressor 68 connected to the turbine 69 by the connecting shaft 70 drives to be introduced into the intake pipe 51. Compress the air.

  In the first bank 12, the exhaust gas discharged from the combustion chamber 22 through the exhaust port 26 and the collecting passage 55 to the first exhaust pipe 57 warms up and activates the first three-way catalyst 59. The harmful substances contained are purified and flow into the exhaust collecting pipe 61. On the other hand, in the second bank 13, the exhaust gas discharged from the combustion chamber 23 through the exhaust port 27 and the collecting passage 56 to the second exhaust pipe 58 warms up and activates the second front three-way catalyst 60. The harmful substances contained are purified and flow into the exhaust collecting pipe 61. The exhaust gas flowing into the exhaust collecting pipe 61 warms and activates the NOx occlusion reduction type catalyst 62, and is released to the atmosphere after the remaining harmful substances are appropriately purified.

  Further, when the engine is started, the first control valve 64 is closed, while the second control valve 65 is opened, and the exhaust gas discharged from the cylinder group of the first bank 12 to the first exhaust pipe 57 is communicated. By bypassing to the second exhaust pipe 58 through the pipe 63, exhaust gases from the cylinder groups of the first and second banks 12, 13 are merged in the second exhaust pipe 58, and then a large amount of exhaust gas is supplied to the second front stage. The second upstream three-way catalyst 60 is warmed up by flowing into the three-way catalyst 60.

  Thereafter, when the warm-up of the second pre-stage three-way catalyst 60 is completed and activated, the first and second control valves 64 and 65 are opened and the exhaust gas from the cylinder group of the first bank 12 is opened. , The exhaust gas from the cylinder group of the second bank 13 is made a rich atmosphere, and the exhaust gas in the lean atmosphere and the exhaust gas in the rich atmosphere are allowed to flow through the exhaust pipes 57 and 58 without passing through the communication pipe 63, By joining the NOx occlusion reduction type catalyst 62 through the exhaust collecting pipe 61, the NOx occlusion reduction type catalyst 62 is warmed up by utilizing the oxidation exothermic reaction at that time.

  When the warming-up of the NOx occlusion reduction type catalyst 62 is completed and activated, the exhaust gas from the cylinder groups of the banks 12 and 13 is released while the first and second control valves 65 and 66 are opened. A stoichiometric atmosphere is established, and the exhaust gas collecting pipe 61 is joined through the exhaust pipes 57 and 58, and then the exhaust gas is caused to flow into the NOx storage reduction catalyst 62 for purification.

  When the engine is under high load and high speed, the first control valve 64 is opened, the second control valve 65 is closed, and the exhaust gas discharged from the cylinder group of the second bank 13 to the second exhaust pipe 58 is discharged. By bypassing the first exhaust pipe 57 through the communication pipe 63, exhaust gas from the cylinder groups of the first and second banks 12 and 13 is merged in the first exhaust pipe 57, and then a large amount of exhaust gas is turbocharged. By introducing the turbocharger 67, the supercharging pressure by the turbocharger 67 is increased, and the output is improved.

  Thus, in the internal combustion engine of the first embodiment, in the V-type 6-cylinder engine, a cylinder group in which a plurality of cylinders are divided and arranged in the left and right first banks 12 and second banks 13 is provided, and each bank is provided. While the intake pipe 51 is connected to the 12 and 13 cylinder groups, the first exhaust pipe 57 and the second exhaust pipe 58 are connected, and the first front three-way catalyst 59 and the second front stage are connected to the exhaust pipes 57 and 58, respectively. The three-way catalyst 60 is provided, and the first control valve 64 and the second control valve 65 are provided. The upstream three-way catalysts 59 and 60 and the control valves 64 and 65 in the exhaust pipes 57 and 58 are connected to the upstream side by the communication pipe 63. In the left and right banks 12, 13, the collecting heads 55, 56, the exhaust pipe connection portions 55a, 56a, and the communication pipe connection portions communicated with the exhaust ports 26, 27 in the respective cylinder heads 20, 21 at the left and right banks 12, 13. 55b and 56b are integrally formed That.

  Therefore, by closing the first control valve 64 or the second control valve 65, the exhaust gas discharged from one of the cylinder groups of the left and right banks 12 and 13 passes through the communication pipe 63 to the other first exhaust pipe 57 or the second control valve 65. 2 When executing bank control to flow into and join the exhaust pipe 58, the communication pipe 63 becomes hot due to the exhaust gas flowing in the communication pipe 63, but the collecting passages 55, 56 and the communication pipe connecting portions 55b, 56b are cylinders. Since it is provided in the heads 20, 21, the length of the communication pipe 63 exposed to the outside is shortened, heat damage to peripheral devices due to the communication pipe 63 can be suppressed, and the communication pipe 63 flows inside. The temperature drop of the exhaust gas can be prevented. Further, since the exhaust gas generated in each bank 12 and 13 flows directly from the collecting passages 55 and 56 to the communication pipe 63, pressure loss can be reduced. As a result, good bank control can be achieved.

  Further, by providing the collecting passages 55 and 56 and the communication pipe connecting portions 55b and 56b in the cylinder heads 20 and 21, heat damage due to the communication pipe 63 is suppressed, so that a heat insulating material is provided around the communication pipe 63. In addition, it is not necessary to increase the distance between the communication pipe 63 and the peripheral device, the apparatus can be made compact and the cost can be reduced, and the degree of freedom in design can be increased to improve the mountability.

  FIG. 3 is a schematic plan view of a V-type 6-cylinder engine that represents an internal combustion engine according to a second embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the same function as what was demonstrated in the Example mentioned above, and the overlapping description is abbreviate | omitted.

  In the V-type six-cylinder engine of the second embodiment, as shown in FIG. 3, a plurality of cylinders are provided in the left and right first and second banks 12 and 13 to constitute a cylinder group. An air cleaner 52 is attached to the air intake port of the intake pipe 51, and an electronic throttle device 54 having a throttle valve 53 is provided on the downstream side of the air cleaner 52. A surge tank 50 is connected to the downstream end of the intake pipe 51, and the surge tank 50 is connected to intake ports 24 and 25 of the banks 12 and 13 via intake manifolds 48 and 49.

  The exhaust ports 26 and 27 communicate with collecting passages 55 and 56 in which exhaust gases discharged from the combustion chambers 22 and 23 gather, and exhaust pipe connecting portions 55a and 56a are connected to the collecting passages 55 and 56, respectively. The first and second exhaust pipes 57 and 58 are connected to each other. In this case, the exhaust ports 26 and 27, the collecting passages 55 and 56, and the exhaust pipe connecting portions 55a and 56a are integrally formed in the cylinder heads 20 and 21 of the left and right banks 12 and 13, respectively. A first front three-way catalyst 59 is attached to the first exhaust pipe 57, while a second front three-way catalyst 60 is attached to the second exhaust pipe 58, and the first and second exhaust pipes 57, 58 are attached. The downstream end of the exhaust gas is joined and connected to an exhaust collecting pipe 61, and a NOx occlusion reduction type catalyst 62 is attached to the exhaust collecting pipe 61. A turbocharger 67 is provided in the first exhaust pipe 57 in the first bank 12.

  Further, the upstream side of the first exhaust pipe 57 and the second exhaust pipe 58 is communicated by the communication pipe 63 on the upstream side in the flow direction of the exhaust gas from the position where the front-stage three-way catalysts 59 and 60 are mounted. . Specifically, one end of the communication pipe 63 is connected to the first bank 12 so as to face the inlet side of the turbocharger 67 in the first exhaust pipe 57, that is, the turbine 69. On the other hand, in the second bank 13, the cylinder head 21 is connected to the collecting passage 56 to form a communication pipe connection portion 56b. The other end of the communication pipe 63 is connected to the pipe connection portion 56b. ing. In this case, the exhaust port 27, the collecting passage 56, the exhaust pipe connection portion 56 a, and the communication pipe connection portion 56 b are formed integrally with the cylinder head 21.

  A first control valve 64 and a second control valve 65 are mounted on the first exhaust pipe 57 and the second exhaust pipe 58 on the downstream side of the upstream three-way catalyst 59, 60 in the flow direction of the exhaust gas. Yes. The first and second control valves 64 and 65 are flow control valves, and the ECU 79 adjusts the flow rate of the exhaust gas flowing through the exhaust pipes 57 and 58 by adjusting the opening degree according to the engine operating state. can do. That is, the ECU 79 can perform various bank controls by changing the combustion state of the banks 12 and 13 and the exhaust gas discharge route.

  In the engine of the second embodiment, as described above, in the first bank 12, one end of the communication pipe 63 is connected to face the inlet side of the turbocharger 67 in the first exhaust pipe 57, In the second bank 13, a collecting passage 56 that communicates with the exhaust ports 26 and 27, an exhaust pipe connection portion 56 a, and a communication pipe connection portion 56 b are integrally formed in the cylinder head 21. Therefore, by shortening the length of the communication pipe 63 exposed to the outside, heat damage due to the communication pipe 63 is prevented, and temperature reduction of the exhaust gas flowing through the communication pipe 63 is prevented. Further, in the first bank 12, the influence of exhaust interference on the second bank 13 side with respect to the turbocharger 67 is reduced.

  Thus, in the internal combustion engine of the second embodiment, in the first bank 12, one end of the communication pipe 63 is connected to the inlet side of the turbocharger 67 in the first exhaust pipe 57, and the second bank 13 In the cylinder head 21, the collecting passage 56 communicating with the exhaust ports 26 and 27, the exhaust pipe connection portion 56a, and the communication pipe connection portion 56b are integrally formed, and one end of the communication pipe 63 is connected to the communication pipe connection portion 56b. It is connected.

  Therefore, although the communication pipe 63 becomes hot due to the exhaust gas flowing in the communication pipe 63, the collecting passage 56 and the communication pipe connection portion 56 b are provided in the cylinder head 21. The length is shortened, the heat damage to the peripheral devices by the communication pipe 63 can be suppressed, and the temperature drop of the exhaust gas flowing through the communication pipe 63 can be prevented. Further, since the exhaust gas generated in the second bank 13 flows directly from the collecting passage 56 to the communication pipe 63, pressure loss can be reduced. As a result, good bank control can be achieved.

  Further, in the first bank 12, the exhaust gas flowing from the combustion chamber 22 through the exhaust port 26 and the collecting passage 55 to the first exhaust pipe 57 branches to the communication pipe 63 on the downstream side of the turbocharger 67. Accordingly, the influence of exhaust interference on the second bank 13 side with respect to the turbocharger 67 is reduced, and the turbocharger 67 can improve the supercharging performance.

  FIG. 4 is a schematic plan view of a V-type 6-cylinder engine that represents an internal combustion engine according to Embodiment 3 of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the same function as what was demonstrated in the Example mentioned above, and the overlapping description is abbreviate | omitted.

  In the V-type six-cylinder engine of the third embodiment, as shown in FIG. 4, a plurality of cylinders are provided in the left and right first and second banks 12 and 13 to constitute a cylinder group. An air cleaner 52 is attached to the air intake port of the intake pipe 51, and an electronic throttle device 54 having a throttle valve 53 is provided on the downstream side of the air cleaner 52. A surge tank 50 is connected to the downstream end of the intake pipe 51, and the surge tank 50 is connected to intake ports 24 and 25 of the banks 12 and 13 via intake manifolds 48 and 49.

  The exhaust ports 26 and 27 communicate with collecting passages 55 and 56 in which exhaust gases discharged from the combustion chambers 22 and 23 gather, and exhaust pipe connecting portions 55a and 56a are connected to the collecting passages 55 and 56, respectively. The first and second exhaust pipes 57 and 58 are connected to each other. In this case, the exhaust ports 26 and 27, the collecting passages 55 and 56, and the exhaust pipe connecting portions 55a and 56a are integrally formed in the cylinder heads 20 and 21 of the left and right banks 12 and 13, respectively. A first front three-way catalyst 59 is attached to the first exhaust pipe 57, while a second front three-way catalyst 60 is attached to the second exhaust pipe 58, and the first and second exhaust pipes 57, 58 are attached. The downstream end of the exhaust gas is joined and connected to an exhaust collecting pipe 61, and a NOx occlusion reduction type catalyst 62 is attached to the exhaust collecting pipe 61. A turbocharger 67 is provided in the first exhaust pipe 57 in the first bank 12.

  Further, the upstream side of the first exhaust pipe 57 and the second exhaust pipe 58 is communicated by the communication pipe 63 on the upstream side in the flow direction of the exhaust gas from the position where the front-stage three-way catalysts 59 and 60 are mounted. . Specifically, the cylinder heads 20, 21 of the left and right banks 12, 13 are formed with communication pipe connection portions 55 b, 56 b that communicate with the collecting passages 55, 56, and each end of the communication pipe 63. Are connected to the pipe connecting portions 55b and 56b. In this case, in addition to the exhaust ports 26 and 27, the collecting passages 55 and 56, and the exhaust pipe connection portions 55a and 56a, communication pipe connection portions 55b and 56b are formed integrally with the cylinder heads 20 and 21, respectively. That is, the exhaust pipe connecting portions 55a and 56a are opened on the side surfaces of the left and right banks 12 and 13 where the cylinder heads 20 and 21 do not face each other, and communicate with the respective side surfaces (opposing surfaces) where the cylinder heads 20 and 21 are opposed. The pipe connecting portions 55b and 56 are opened.

  A first control valve 64 and a second control valve 65 are mounted on the first exhaust pipe 57 and the second exhaust pipe 58 on the downstream side of the upstream three-way catalyst 59, 60 in the flow direction of the exhaust gas. Yes. The first and second control valves 64 and 65 are flow control valves, and the ECU 79 adjusts the flow rate of the exhaust gas flowing through the exhaust pipes 57 and 58 by adjusting the opening degree according to the engine operating state. can do. That is, the ECU 79 can perform various bank controls by changing the combustion state of the banks 12 and 13 and the exhaust gas discharge route.

  In the engine of the third embodiment, as described above, the exhaust ports 26 and 27, the collecting passages 55 and 56, the exhaust pipe connecting portions 55a and 56a, and the exhaust ports 26 and 27 are provided in the cylinder heads 20 and 21 in the left and right banks 12 and 13, respectively. The communication pipe connection portions 55b and 56b are integrally formed, and the communication pipe connection portions 55b and 56b are formed so as to open on the opposing surfaces of the cylinder heads 20 and 21. Therefore, by shortening the length of the communication pipe 63 exposed to the outside, heat damage due to the communication pipe 63 is prevented, and temperature reduction of the exhaust gas flowing through the communication pipe 63 is prevented.

  As described above, in the internal combustion engine of the third embodiment, the collecting passages 55 and 56 that communicate with the exhaust ports 26 and 27 and the communication pipe connection portions 55b and the cylinder heads 20 and 21 in the left and right banks 12 and 13 are provided. 56b is integrally formed, and the communicating pipe connecting portions 55b and 56b are formed by opening on the opposing surfaces of the cylinder heads 20 and 21, and each end of the communicating pipe 63 disposed between the cylinder heads 20 and 21. The portion is connected to the communication pipe connecting portions 55b and 56b.

  Therefore, although the communication pipe 63 becomes hot due to the exhaust gas flowing in the communication pipe 63, the collecting passage 56 and the communication pipe connection portion 56 b are provided in the cylinder head 21. The length is shortened to the gap distance between the cylinder heads 20 and 21, the heat damage to the peripheral devices by the communication pipe 63 can be suppressed, and the temperature reduction of the exhaust gas flowing through the communication pipe 63 can be prevented. Can do. Further, since the exhaust gas generated in the second bank 13 flows directly from the collecting passage 56 to the communication pipe 63, pressure loss can be reduced. As a result, good bank control can be achieved.

FIG. 5 is a schematic plan view of a V-type 6-cylinder engine that represents an internal combustion engine according to Embodiment 4 of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the same function as what was demonstrated in the Example mentioned above, and the overlapping description is abbreviate | omitted.

  In the V-type six-cylinder engine of the fourth embodiment, as shown in FIG. 5, a plurality of cylinders are provided in the left and right first and second banks 12 and 13 to constitute a cylinder group. An air cleaner 52 is attached to the air intake port of the intake pipe 51, and an electronic throttle device 54 having a throttle valve 53 is provided on the downstream side of the air cleaner 52. A surge tank 50 is connected to the downstream end of the intake pipe 51, and the surge tank 50 is connected to intake ports 24 and 25 of the banks 12 and 13 via intake manifolds 48 and 49.

  The exhaust ports 26 and 27 communicate with collecting passages 55 and 56 in which exhaust gases discharged from the combustion chambers 22 and 23 gather, and exhaust pipe connecting portions 55a and 56a are connected to the collecting passages 55 and 56, respectively. The first and second exhaust pipes 57 and 58 are connected to each other. In this case, the exhaust ports 26 and 27, the collecting passages 55 and 56, and the exhaust pipe connecting portions 55a and 56a are integrally formed in the cylinder heads 20 and 21 of the left and right banks 12 and 13, respectively. A first front three-way catalyst 59 is attached to the first exhaust pipe 57, while a second front three-way catalyst 60 is attached to the second exhaust pipe 58, and the first and second exhaust pipes 57, 58 are attached. The downstream end of the exhaust gas is joined and connected to an exhaust collecting pipe 61, and a NOx occlusion reduction type catalyst 62 is attached to the exhaust collecting pipe 61. A turbocharger 67 is provided in the first exhaust pipe 57 in the first bank 12.

  Further, the upstream side of the first exhaust pipe 57 and the second exhaust pipe 58 is communicated by the communication pipe 63 on the upstream side in the flow direction of the exhaust gas from the position where the front-stage three-way catalysts 59 and 60 are mounted. . Specifically, the cylinder heads 20, 21 of the left and right banks 12, 13 are formed with communication pipe connection portions 55 b, 56 b that communicate with the collecting passages 55, 56, and each end of the communication pipe 63. Are connected to the pipe connecting portions 55b and 56b. In this case, in addition to the exhaust ports 26 and 27, the collecting passages 55 and 56, and the exhaust pipe connection portions 55a and 56a, communication pipe connection portions 55b and 56b are formed integrally with the cylinder heads 20 and 21, respectively.

  A first control valve 64 and a second control valve 65 are mounted on the first exhaust pipe 57 and the second exhaust pipe 58 on the downstream side of the upstream three-way catalyst 59, 60 in the flow direction of the exhaust gas. Yes. The first and second control valves 64 and 65 are flow control valves, and the ECU 79 adjusts the flow rate of the exhaust gas flowing through the exhaust pipes 57 and 58 by adjusting the opening degree according to the engine operating state. can do. That is, the ECU 79 can perform various bank controls by changing the combustion state of the banks 12 and 13 and the exhaust gas discharge route.

  In the engine of the fourth embodiment, as described above, the exhaust ports 26 and 27, the collecting passages 55 and 56, the exhaust pipe connection portions 55a and 56a, and the exhaust ports 26 and 27 are provided in the cylinder heads 20 and 21 in the left and right banks 12 and 13, respectively. The communication pipe connection portions 55b and 56b are integrally formed, and the end of the communication pipe 63 is connected to the communication pipe connection portions 55b and 56b, and heat can be exchanged between the exhaust gas and the cooling medium in the communication pipe 63. A heat exchanger 91 is provided. The heat exchanger 91 is configured by mounting a hollow cylindrical communication pipe on the outer peripheral portion of the communication pipe 63, and engine cooling water is circulated as a cooling medium in the communication pipe. Therefore, by shortening the length of the communication pipe 63 exposed to the outside, heat damage due to the communication pipe 63 is prevented, and temperature reduction of the exhaust gas flowing through the communication pipe 63 is prevented. Further, heat exchange is performed between the exhaust gas in the communication pipe 63 and the engine cooling water in the heat exchanger 91, whereby the communication pipe 63 is cooled to prevent heat damage and the engine cooling water is heated. And warm-up is promoted.

  As described above, in the internal combustion engine of the fourth embodiment, the collecting passages 55 and 56 that communicate with the exhaust ports 26 and 27 and the communication pipe connecting portions 55b and the cylinder heads 20 and 21 in the left and right banks 12 and 13 are provided. 56b is integrally formed, and each end of the communication pipe 63 is connected to the communication pipe connection portions 55b and 56b, and the heat exchanger 91 performs heat exchange between the exhaust gas and the engine coolant in the communication pipe 63. Is provided.

  Therefore, although the communication pipe 63 becomes hot due to the exhaust gas flowing in the communication pipe 63, the collecting passage 56 and the communication pipe connection portion 56 b are provided in the cylinder head 21. The length is shortened, and the exhaust gas in the communication pipe 63 is cooled by the engine coolant in the heat exchanger 91, so that heat damage to peripheral devices by the communication pipe 63 can be suppressed.

  Further, heat exchange is performed between the exhaust gas in the communication pipe 63 and the engine cooling water in the heat exchanger 91, whereby the engine cooling water is heated to promote engine warm-up and reduce friction. On the other hand, since the exhaust gas is cooled, the exhaust gas temperature at the time of high engine load decreases, and the fuel cooling to the combustion chambers 22 and 23 can be stopped to improve the fuel consumption.

FIG. 6 is a schematic plan view of a V-type 6-cylinder engine that represents an internal combustion engine according to Embodiment 5 of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the same function as what was demonstrated in the Example mentioned above, and the overlapping description is abbreviate | omitted.

  In the V-type six-cylinder engine of the fifth embodiment, as shown in FIG. 6, a plurality of cylinders are provided in the left and right first and second banks 12 and 13 to constitute a cylinder group. In the cylinder heads 20, 21 of the banks 12, 13, the exhaust ports 26, 27 communicate with the collecting passages 55, 56 where the exhaust gas discharged from the combustion chambers 22, 23 gathers. First and second exhaust pipes 57 and 58 are connected to 55 and 56 via exhaust pipe connection portions 55a and 56a. A first front three-way catalyst 59 is attached to the first exhaust pipe 57, while a second front three-way catalyst 60 is attached to the second exhaust pipe 58, and the first and second exhaust pipes 57, 58 are attached. The downstream end of the exhaust gas is joined and connected to an exhaust collecting pipe 61, and a NOx occlusion reduction type catalyst 62 is attached to the exhaust collecting pipe 61. A turbocharger 67 is provided in the first exhaust pipe 57 in the first bank 12.

  The cylinder heads 20 and 21 of the left and right banks 12 and 13 are formed with communication pipe connection portions 55b and 56b in communication with the collecting passages 55 and 56, respectively. It is connected with the pipe connection parts 55b and 56b. In this case, in addition to the exhaust ports 26 and 27, the collecting passages 55 and 56, and the exhaust pipe connection portions 55a and 56a, communication pipe connection portions 55b and 56b are formed integrally with the cylinder heads 20 and 21, respectively. The first control valve 64 and the second control valve 65 are mounted on the first exhaust pipe 57 and the second exhaust pipe 58, and the ECU 79 flows through the exhaust pipes 57 and 58 by adjusting the opening degree. The flow rate of the exhaust gas can be adjusted, and bank control for changing the combustion state of the banks 12 and 13 and the exhaust gas discharge route is possible.

  In the engine of the fifth embodiment, the exhaust ports 26 and 27, the collecting passages 55 and 56, the exhaust pipe connecting portions 55a and 56a, and the communication pipe connecting portion 55b are provided in the cylinder heads 20 and 21 in the left and right banks 12 and 13, respectively. , 56b are integrally formed, and the end portion of the communication pipe 63 is connected to the communication pipe connection portions 55b, 56b, and the heat exchanger 91 capable of exchanging heat between the exhaust gas and the cooling medium. Is provided. The ECU 79 controls the opening and closing of the first control valve 64 and the second control valve 65 according to the engine operating state, thereby exchanging heat between the exhaust gas and the engine coolant (cooling medium) by the heat exchanger 91. I try to change the amount.

  For example, the ECU 79 closes the first control valve 64 and opens the second control valve 65 when the engine is warmed up, and communicates exhaust gas discharged from the cylinder group of the first bank 12 into the collecting passage 55. Then, the engine cooling water in the heat exchanger 91 is heated by the exhaust gas flowing in the communication pipe 63, and warming up of the engine is promoted. Further, when starting the engine, the ECU 79 closes the first control valve 64 and opens the second control valve 65, and exhaust gas exhausted from the cylinder group of the first bank 12 to the collecting passage 55 through the communication pipe 63. By flowing through the second exhaust pipe 58, the engine coolant in the heat exchanger 91 is heated by the exhaust gas flowing through the communication pipe 63, and the heater performance is improved. Further, the ECU 79 opens the first control valve 64 and the second control valve 65 when the engine is heavily loaded, and the exhaust pipe discharged from the cylinder groups of the banks 12 and 13 to the collecting passages 55 and 56 is connected to the communication pipe 63. By flowing through the exhaust pipes 57 and 58 without passing through, the heating of the engine cooling water in the heat exchanger 91 by the exhaust gas flowing through the communication pipe 63 is stopped, and the temperature rise of the engine cooling water is suppressed.

  As described above, in the internal combustion engine of the fifth embodiment, the collecting passages 55 and 56 communicating with the exhaust ports 26 and 27 and the communication pipe connecting portions 55b and the cylinder heads 20 and 21 in the left and right banks 12 and 13 are provided. 56b is integrally formed, and each end of the communication pipe 63 is connected to the communication pipe connection portions 55b and 56b, and the heat exchanger 91 performs heat exchange between the exhaust gas and the engine coolant in the communication pipe 63. And the ECU 79 controls the opening and closing of the first control valve 64 and the second control valve 65 in accordance with the engine operating state so as to change the heat exchange amount between the exhaust gas and the engine coolant by the heat exchanger 91. I have to.

  Therefore, although the communication pipe 63 becomes hot due to the exhaust gas flowing in the communication pipe 63, the collecting passage 56 and the communication pipe connection portion 56 b are provided in the cylinder head 21. The length is shortened, and the exhaust gas in the communication pipe 63 is cooled by the engine coolant in the heat exchanger 91, so that heat damage to peripheral devices by the communication pipe 63 can be suppressed.

  Further, the ECU 79 controls the opening and closing of the control valves 64 and 65 according to the engine operating state, and performs heat exchange between the exhaust gas in the communication pipe 63 and the engine coolant in the heat exchanger 91 as necessary. Thus, effects such as promotion of warming up of the engine, securing of the performance of the heater, and high temperature of the engine cooling water at the time of high engine load can be achieved.

FIG. 7 is a schematic plan view of a V-type 6-cylinder engine that represents an internal combustion engine according to Embodiment 6 of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the same function as what was demonstrated in the Example mentioned above, and the overlapping description is abbreviate | omitted.

  In the V-type 6-cylinder engine of the sixth embodiment, as shown in FIG. 7, a plurality of cylinders are provided in the left and right first and second banks 12 and 13 to constitute a cylinder group. In the cylinder heads 20, 21 of the banks 12, 13, the exhaust ports 26, 27 communicate with the collecting passages 55, 56 where the exhaust gas discharged from the combustion chambers 22, 23 gathers. First and second exhaust pipes 57 and 58 are connected to 55 and 56 via exhaust pipe connection portions 55a and 56a. A first front three-way catalyst 59 is attached to the first exhaust pipe 57, while a second front three-way catalyst 60 is attached to the second exhaust pipe 58, and the first and second exhaust pipes 57, 58 are attached. The downstream end of the exhaust gas is joined and connected to an exhaust collecting pipe 61, and a NOx occlusion reduction type catalyst 62 is attached to the exhaust collecting pipe 61. A turbocharger 67 is provided in the first exhaust pipe 57 in the first bank 12.

  The cylinder heads 20 and 21 of the left and right banks 12 and 13 are formed with communication pipe connection portions 55b and 56b in communication with the collecting passages 55 and 56, respectively. It is connected with the pipe connection parts 55b and 56b. In this case, in addition to the exhaust ports 26 and 27, the collecting passages 55 and 56, and the exhaust pipe connection portions 55a and 56a, communication pipe connection portions 55b and 56b are formed integrally with the cylinder heads 20 and 21, respectively. The first control valve 64 and the second control valve 65 are mounted on the first exhaust pipe 57 and the second exhaust pipe 58, and the ECU 79 flows through the exhaust pipes 57 and 58 by adjusting the opening degree. The flow rate of the exhaust gas can be adjusted, and bank control for changing the combustion state of the banks 12 and 13 and the exhaust gas discharge route is possible.

  In the engine of the sixth embodiment, the exhaust ports 26 and 27, the collecting passages 55 and 56, the exhaust pipe connecting portions 55a and 56a, and the communication pipe connecting portion 55b are provided in the cylinder heads 20 and 21 in the left and right banks 12 and 13, respectively. , 56b are integrally formed, and the end portion of the communication pipe 63 is connected to the communication pipe connection portions 55b, 56b, and the heat exchanger 91 capable of exchanging heat between the exhaust gas and the cooling medium. Is provided. The heat exchanger 91 is connected to the heater unit 92. That is, the cooling pipe 93 from the heater unit 92 is connected to the engine (the cylinder head 21 of the second bank 13), the cooling pipe 94 from this engine is connected to the heat exchanger 91, and the cooling from the heat exchanger 91 is performed. A pipe 95 is connected to the heater unit 92.

  Therefore, when the engine is started, the first control valve 64 is closed and the second control valve 65 is opened, and the exhaust gas discharged from the cylinder group of the first bank 12 to the collecting passage 55 is passed through the communication pipe 63 to the second exhaust. By flowing through the pipe 58, the engine coolant in the heat exchanger 91 is heated by the exhaust gas flowing through the communication pipe 63. At this time, the engine cooling water circulating from the engine through the cooling pipe 94 to the heat exchanger 91 takes heat from the exhaust gas by the heat exchanger 91 and rises in temperature, and then directly passes through the cooling pipe 95. Circulation to the heater unit 92 improves the heater function, and warm air is supplied into the room at an early stage from the start of the engine.

  As described above, in the internal combustion engine of the sixth embodiment, in the cylinder heads 20 and 21 in the left and right banks 12 and 13, the collecting passages 55 and 56 communicating with the exhaust ports 26 and 27, and the communication pipe connecting portions 55b and 56b is integrally formed, and each end of the communication pipe 63 is connected to the communication pipe connection portions 55b and 56b, and the heat exchanger 91 performs heat exchange between the exhaust gas and the engine coolant in the communication pipe 63. And the heat exchanger 91 is connected to the heater unit 92.

  Therefore, although the communication pipe 63 becomes hot due to the exhaust gas flowing in the communication pipe 63, the collecting passage 56 and the communication pipe connection portion 56 b are provided in the cylinder head 21. The length is shortened, and the exhaust gas in the communication pipe 63 is cooled by the engine coolant in the heat exchanger 91, so that heat damage to peripheral devices by the communication pipe 63 can be suppressed.

  Further, when the engine is started, high-temperature engine cooling water whose temperature has been increased by taking heat from the exhaust gas by the heat exchanger 91 circulates directly to the heater unit 92 through the cooling pipe 95, thereby starting the engine. Thus, warm air can be supplied to the room at an early stage, and the heater performance can be improved.

  In each of the above-described embodiments, the front three-way catalyst 59, 60 is attached to both the exhaust pipes 57, 58 of the banks 12, 13, but the front three-way catalyst is attached to only one of the exhaust pipes 57, 58. A catalyst may be attached and a three-way catalyst may be provided in the collective exhaust pipe 61. In addition, the turbocharger 67 is provided in the first bank 12 and the first and second banks 12 and 13 are supercharged. However, the turbocharger 67 may be provided in both the banks 12 and 13 or both banks 12 and 13 may be provided. , 13 may be removed from the turbocharger.

  In each of the above-described embodiments, a V-type 6-cylinder engine is applied as the internal combustion engine. However, the engine type, the number of cylinders, and the like are not limited to the embodiments. Further, the fuel injection type of the internal combustion engine is the in-cylinder injection type, but it may be a port injection type, and the combustion mode may not be a lean combustion type, and in this case, the NOx occlusion reduction type catalyst becomes unnecessary. .

  As described above, the internal combustion engine according to the present invention enables good bank control by preventing thermal damage caused by the communication pipe communicating with the left and right exhaust passages and reducing the size of the apparatus. It is also useful for internal combustion engines.

1 is a schematic plan view of a V-type 6-cylinder engine that represents an internal combustion engine according to Embodiment 1 of the present invention. 1 is a schematic cross-sectional view of a V-type 6-cylinder engine according to Embodiment 1. FIG. It is a schematic plan view of the V type 6 cylinder engine showing the internal combustion engine which concerns on Example 2 of this invention. It is a schematic plan view of the V type 6 cylinder engine showing the internal combustion engine which concerns on Example 3 of this invention. It is a schematic plan view of the V type 6 cylinder engine showing the internal combustion engine which concerns on Example 4 of this invention. It is a schematic plan view of the V type 6 cylinder engine showing the internal combustion engine which concerns on Example 5 of this invention. It is a schematic plan view of the V type 6 cylinder engine showing the internal combustion engine which concerns on Example 6 of this invention.

Explanation of symbols

12 First bank 13 Second bank 16, 17 Piston 20, 21 Cylinder head 22, 23 Combustion chamber 24, 25 Intake port 26, 27 Exhaust port 28, 29 Intake valve 30, 31 Exhaust valve 51 Intake pipe (intake passage)
54 Electronic throttle device 55, 56 Collecting passage (exhaust passage)
55a, 56a Exhaust pipe connection (exhaust passage)
55b, 56b Communication pipe connection 57 First exhaust pipe (exhaust passage)
58 Second exhaust pipe (exhaust passage)
59 First three-way catalyst (purification catalyst)
60 Second front three-way catalyst (purification catalyst)
61 exhaust collecting pipe 62 NOx occlusion reduction type catalyst 63 communication pipe (communication passage)
64 First control valve 65 Second control valve 67 Turbocharger 72, 73 Injector 77, 78 Spark plug 79 Electronic control unit, ECU
91 Heat exchanger 92 Heater unit

Claims (6)

  There are two cylinder groups in which a plurality of cylinders are divided into left and right banks, and an intake passage is provided for each cylinder group, while an exhaust passage is provided independently. A control valve for adjusting the flow rate of the exhaust gas is provided, and a purification catalyst is provided in at least one of the exhaust passages, and the control valve in each exhaust passage and the upstream side of the purification catalyst communicate with each other by a communication passage. In at least one of the left and right banks, the exhaust passage has a collecting passage in which exhaust gas discharged from the cylinder group collects, and the collecting passage and the collecting passage An internal combustion engine characterized in that a connecting portion of the communication passage is provided in a cylinder head.   2. The internal combustion engine according to claim 1, wherein a supercharger is provided in the other exhaust passage of the left and right banks, and the communication passage is connected to an inlet side of the supercharger in the exhaust passage. An internal combustion engine.   2. The internal combustion engine according to claim 1, wherein the exhaust passages in the left and right banks each have a collective passage in which exhaust gas discharged from the cylinder group collects, and the collective passage and the communication passage to the collective passage The internal combustion engine is characterized in that the connecting portion is provided in the cylinder head, and the connecting portion is opened on a facing surface of each cylinder head in the left and right banks and connected by a communication pipe.   4. The internal combustion engine according to claim 1, wherein a heat exchanger capable of exchanging heat between the exhaust gas and the cooling medium is provided in the communication path.   5. The internal combustion engine according to claim 4, wherein the amount of heat exchange between the exhaust gas and the cooling medium by the heat exchanger is changed by opening and closing the control valve according to an operating state. organ.   6. The internal combustion engine according to claim 4, wherein the heat exchanger is connected to a heater unit.

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