JP4483556B2 - Internal combustion engine - Google Patents

Description

  The present invention relates to a multi-cylinder internal combustion engine having two banks and each cylinder in each bank exploding at unequal intervals.

  2. Description of the Related Art Conventionally, there is a so-called V-type multi-cylinder internal combustion engine having two banks and a plurality of cylinders arranged in each bank.

  In general, in a multi-cylinder internal combustion engine, the firing order of each cylinder is determined so as to satisfy various requirements such as equal combustion between the cylinders and no torsional vibration in the crankshaft. It is done. For example, in order to satisfy the requirements in a V-type 8-cylinder internal combustion engine in which the first cylinder, the second cylinder,..., The eighth cylinder are alternately arranged from the left and right from the front of the engine in the left bank, the first cylinder → 8 In general, ignition is performed at every crank angle of 90 ° CA in the order of No. cylinder → No. 7 cylinder → No. 3 cylinder → No. 6 cylinder → No. 5 cylinder → No. 4 cylinder → No. 2 cylinder. Thus, in this V-type 8-cylinder internal combustion engine, ignition and explosion of each cylinder in the left and right banks are at unequal intervals.

  On the other hand, in a V-type multi-cylinder internal combustion engine, combustion gas is discharged from each cylinder to an exhaust manifold outside the engine provided for each of the left and right banks. Therefore, in the above-described V-type multi-cylinder internal combustion engine that performs ignition and explosion at unequal intervals, exhaust interference occurs due to a difference in exhaust pulsation between specific cylinders, thereby causing internal EGR (combustion chamber) between the cylinders. Therefore, the intake air charging efficiency between the cylinders (in other words, the air-fuel ratio) varies.

  In view of this, Japanese Patent Application Laid-Open No. H10-228561 discloses a technique for making the internal EGR amount uniform between the cylinders by making the shape of the collection portion of the exhaust manifold an ejector shape.

  Incidentally, it is generally known that the internal EGR lowers the combustion temperature and reduces the discharge amount of HC and NOx. It is also known that the internal EGR can reduce pump loss and reduce the fuel consumption rate. For this reason, in a conventional internal combustion engine, by providing a valve overlap period (a period in which the intake valve and the exhaust valve are simultaneously open) between the exhaust stroke and the intake stroke, the internal EGR amount is increased, and HC and It aims to reduce NOx emissions and fuel consumption.

  However, if the valve overlap period is provided in a V-type multi-cylinder internal combustion engine, in each cylinder arranged in the same bank, the valve overlap period of a certain cylinder and the blow-down timing of exhaust of a specific cylinder (exhaust valve Therefore, the difference in exhaust pulsation between the two cylinders causes a difference in the internal EGR amount between the cylinders.

  Taking the V-type 8-cylinder internal combustion engine that is ignited in the above-mentioned ignition sequence as an example, the effects of blowdown gas in the 7th and 5th cylinders of the same bank are applied to the 1st and 3rd cylinders of the left bank. The internal EGR amount increases in response to each, and the internal EGR amount is influenced by the blowdown gas of the 4th and 8th cylinders of the same bank in the 6th and 2nd cylinders of the right bank. Become more.

  For this reason, in Patent Document 2 below, the internal EGR amount is reduced by changing the shape of the exhaust cam between the cylinder having a large internal EGR amount and the cylinder having a small internal EGR amount, thereby reducing the overlapping state of the valve overlap period and the blowdown time. The technique which aims at equalization of this is disclosed.

JP-A-3-70810 Special table 2003-515025 gazette

  However, even if the shape of the manifold portion of the exhaust manifold is changed to an ejector shape as in the above-mentioned Patent Document 1, the internal EGR amount between the cylinders is not sufficiently uniform. Therefore, variations in intake air charging efficiency (air-fuel ratio) between specific cylinders cannot be eliminated, and combustion fluctuations occur between the cylinders, leading to a reduction in shaft torque due to the unstable combustion. End up. Further, due to the difference in the internal EGR amount between the cylinders, the valve overlap period is limited to the combustion limit of the cylinder having a large internal EGR amount and cannot be expanded. The effect of reduction and reduction in fuel consumption rate cannot be achieved.

  Further, in Patent Document 2, it is difficult to extend the valve overlap period, and even if the shaft torque can be improved, the effects of reducing the discharge amount of HC and NOx and lowering the fuel consumption rate can be sufficiently obtained. I can't.

  Thus, conventionally, since it is difficult to expand the valve overlap period, it is not possible to achieve both improvement in shaft torque by stabilizing combustion, reduction in HC and NOx emissions, and reduction in fuel consumption rate, It was not possible to meet the conflicting demands of recent improvements in engine performance and environmental performance.

  SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an internal combustion engine provided with a means for equalizing an internal EGR amount between cylinders, which can improve the disadvantages of the conventional example and can extend a valve overlap period. .

  In order to achieve the above object, according to the first aspect of the present invention, in an internal combustion engine having two banks and each cylinder on the same bank exploding at unequal intervals, the blow-down gas discharged from the blow-down gas generating cylinder is discharged. Blow down gas pressure wave attenuating means for attenuating the pressure wave of the down gas is provided.

  According to the first aspect of the present invention, it is possible to attenuate the blowdown gas and delay the arrival time of the positive pressure wave of the blowdown gas to the other cylinder. Therefore, the exhaust pulsation difference between the blow-down gas generating cylinder and the blow-down gas inflow cylinder can be reduced, and exhaust interference between the cylinders can be reduced. Therefore, the internal EGR amount between the cylinders can be reduced. As a result, the charging efficiency (air-fuel ratio) of the intake air can be made uniform.

Here, examples of the blowdown gas pressure wave damping means, exhaust passage for communicating the hand exhaust path and the other of the cylinders arranged in banks of each of the exhaust path of each of the cylinders arranged in a bank of A communication means is provided.

Further, as in the invention described in claim 2 , for each bank, an exhaust path through which exhaust gas from each cylinder arranged on the same bank flows, and a catalyst device into which exhaust gas flows through the exhaust path, respectively. provided, as the blowdown gas pressure wave damping means, further provided with a communicating pipe for communicating in front of the exhaust path of each bank respective catalytic converter.

According to a third aspect of the present invention, a blowdown gas exhaust path extending structure in which an exhaust path of a blowdown gas generating cylinder is extended is further provided as the blowdown gas pressure wave attenuating means.

In this case , as in the invention described in claim 4, there is provided a first catalyst device into which exhaust gas flows and a second catalyst device into which exhaust gas which has passed through the first catalyst device flows, and the blowdown gas exhaust path extension is provided. The blowdown gas is arranged downstream of the first catalyst device between the exhaust path of the blowdown gas generating cylinder and the exhaust path of the blowdown gas inflow cylinder where the internal EGR amount increases due to the blowdown gas. It may be provided as a bypass passage to be bypassed.

  The internal combustion engine according to the present invention can make the internal EGR amount between the cylinders, and hence the intake air charging efficiency (air-fuel ratio) uniform, so that the shaft torque can be improved. Further, since the uniform state of the internal EGR amount between the cylinders and the uniform state of the charging efficiency (air-fuel ratio) of the intake air can be maintained even if the valve overlap period is expanded, the valve overlap period As a result, the amount of internal EGR can be increased, and the amount of HC and NOx emissions can be reduced and the fuel consumption rate can be reduced.

  Embodiments of an internal combustion engine according to the present invention will be described below in detail with reference to the drawings. The present invention is not limited to the embodiments.

  A first embodiment of an internal combustion engine according to the present invention will be described with reference to FIGS. Here, reference numeral 1 in FIGS. 1 and 2 indicates the internal combustion engine of the first embodiment.

  First, the configuration of the internal combustion engine 1 of the first embodiment will be described.

The internal combustion engine 1 of the first embodiment has two banks, and the first cylinder # 1, the second cylinder # 2,..., The eighth cylinder alternately from the left and right from the front of the left bank (the left side in FIG. 1). This is a so-called V-type eight-cylinder internal combustion engine in which cylinder # 8 is arranged, and includes a V-shaped cylinder block 1a and two cylinder heads 1b _LH and 1b _RH . That is, the V-type 8-cylinder internal combustion engine 1 of the first embodiment is provided with the first cylinder # 1, the third cylinder # 3, the fifth cylinder # 5, the seventh cylinder # 7 in one bank, No. 2 cylinder # 2, No. 4 cylinder # 4, No. 6 cylinder # 6, No. 8 cylinder # 8 are provided in this bank.

First, on the side of one bank (hereinafter referred to as “left bank”) having the first cylinder # 1, the third cylinder # 3, the fifth cylinder # 5, and the seventh cylinder # 7, each cylinder # 1 is provided. , # 3, # 5, and # 7, the exhaust ports 1b _{# 1} , 1b _{# 3} , 1b _{# 5} , and 1b _{# 7 of} the cylinder head 1b _LH and the respective exhaust ports 1b _{# 1} and 1b _{# 3.} , 1b _{# 5} , 1b _{# 7} , an exhaust manifold 2 _LH , first and second catalytic devices 3 _LH , 4 _LH arranged downstream of the exhaust manifold 2 _LH , and the first and second a first exhaust pipe 5 _LH for communicating the catalytic converter 3 _LH, 4 _LH, a second exhaust pipe 6 _LH to its second exhaust gas passing through the catalytic converter 4 _LH flows is provided for.

On the other hand, on the other bank (hereinafter referred to as “right bank”) side having the second cylinder # 2, the fourth cylinder # 4, the sixth cylinder # 6, and the eighth cylinder # 8, the respective cylinders similarly. Exhaust ports 1b _{# 2} , 1b _{# 4} , 1b _{# 6} , 1b _{# 8 of} cylinder head 1b _RH communicating with # 2, # 4, # 6, # 8 individually and their respective exhaust ports 1b _{# 2} , 1b _{# 4,} 1b and # _6, 1b exhaust manifold 2 _RH communicating with # _8, a first and a second catalytic converter 3 _RH, 4 _RH deployed downstream of the exhaust manifold 2 _RH, the first and a first exhaust pipe 5 _RH for communicating the second catalytic converter 3 _RH, 4 _RH, a second _RH exhaust pipe 6 that the second catalytic converter 4 exhaust gas passed through the _RH flows is provided.

Thus, in the internal combustion engine 1 of the first embodiment, the exhaust paths are provided for the respective left and right banks, and as shown in FIG. 1, the exhaust gas flowing through the respective exhaust paths is the third exhaust pipe 7. In one route. The respective exhaust paths do not necessarily have to be combined into one path by the third exhaust pipe 7. Further, the first exhaust pipes 5 _LH and 5 _RH are gathered in one path, and one catalyst device is arranged on the downstream side of the gathered portion instead of the two second catalyst devices 4 _LH and 4 _RH. May be.

Here, the exhaust manifold 2 _LH of the left bank in the first embodiment is connected to the first to fourth exhaust passages 2 individually communicating with the respective exhaust ports 1b _{# 1} , 1b _{# 3} , 1b _{# 5} , 1b _{# 7. # 1} , 2 _{# 3} , 2 _{# 5} , 2 _{# 7} and these 1st to 4th exhaust passages 2 _{# 1} , 2 _{# 3} , 2 _{# 5} , 2 _{# 7} It is composed of a passage 2a _1. On the other hand, the exhaust manifold 2 _RH in the right bank has first to fourth exhaust passages 2 _{# 2} , 2 _# individually communicating with the respective exhaust ports 1b _{# 2} , 1b _{# 4} , 1b _{# 6} , 1b _{# 8. 4} , 2 _{# 6} , 2 _{# 8} and a collecting passage 2 a ₂ for collecting the exhaust gases of these first to fourth exhaust passages 2 _{# 2} , 2 _{# 4} , 2 _{# 6} , 2 _{# 8} in one route It is configured.

  By the way, the ignition order of the internal combustion engine 1 of the first embodiment is determined so as to satisfy various requirements such as equal combustion of the cylinders # 1 to # 8. For example, here, the first cylinder # 1 → 8th cylinder # 8 → 7th cylinder # 7 → 3rd cylinder # 3 → 6th cylinder # 6 → 5th cylinder # 5 → 4th cylinder # 4 → 2nd cylinder An example is given in which ignition is performed every crank angle of about 90 ° CA in the order of # 2.

  When ignition is performed in such an ignition sequence, the ignition / explosion intervals of the respective cylinders # 1, # 3, # 5, # 7 in the left bank, and the respective cylinders # 2, # 4, # 6 in the right bank , # 8 ignition / explosion intervals are unequal, and the internal EGR amount varies due to exhaust interference between specific cylinders, resulting in variations in intake air charging efficiency (air-fuel ratio) between the cylinders. End up.

  That is, in general, in an internal combustion engine, a valve overlap period in which an intake valve and an exhaust valve are simultaneously opened is set, and a period in which a valve overlap period of a certain cylinder and an exhaust blowdown timing of a specific cylinder overlap. Exists. For this reason, exhaust interference occurs due to the difference in exhaust pulsation between the cylinders, and this causes a difference in the internal EGR amount, resulting in variations in the charging efficiency (air-fuel ratio) of intake air.

  For example, in the V-type eight-cylinder internal combustion engine 1, as shown in FIG. 2-1, between the first cylinder # 1 and the seventh cylinder # 7 and between the third cylinder # 3 and the fifth cylinder # 5. , There is a state in which the exhaust valve is open at the same time between the sixth cylinder # 6 and the fourth cylinder # 4 and between the second cylinder # 2 and the eighth cylinder # 8. For this reason, when the exhaust valves of the seventh cylinder # 7, the fifth cylinder # 5, the fourth cylinder # 4 and the eighth cylinder # 8 are opened, the pressure wave of the blowdown gas is in the valve overlap period. No. 1 cylinder # 1, No. 3 cylinder # 3, No. 6 cylinder # 6 and No. 2 cylinder # 2 reach, and exhaust interference occurs due to the difference in exhaust pulsation between the respective cylinders. As a result, exhaust from the first cylinder # 1, third cylinder # 3, sixth cylinder # 6, and second cylinder # 2 is not sufficiently performed, so the internal EGR amount between the respective cylinders differs. And the intake air charging efficiency (air-fuel ratio) varies.

  Also, in recent internal combustion engines, the opening and closing timings of the intake valve and the exhaust valve are set in order to reduce the HC and NOx emission amount and the fuel consumption rate by increasing the internal EGR amount of each cylinder. Means such as a so-called variable valve timing mechanism that can be varied are provided, and a suitable valve overlap period is variably set as appropriate. Therefore, when such means as a variable valve timing mechanism is provided in each cylinder # 1 to # 8 in the V-type 8-cylinder internal combustion engine 1, and the valve overlap period is expanded as shown in FIG. The difference in internal EGR amount occurs between the same cylinders as described above, and the intake air charging efficiency (air-fuel ratio) varies greatly.

  Hereinafter, the cylinders # 4, # 5, # 7, and # 8 in which the amount of internal EGR is reduced by generating blowdown gas under the respective circumstances are also referred to as “blowdown gas generating cylinders” as appropriate. In addition, the cylinders # 6, # 3, # 1, and # 2 whose internal EGR amount increases under the influence of the blowdown gas under the respective circumstances are also referred to as “blowdown gas inflow cylinders” as appropriate.

  As described above, in the V-type 8-cylinder internal combustion engine 1, the intake air charging efficiency (air-fuel ratio) varies between the cylinders due to the difference in the internal EGR amount between the cylinders. The torque cannot be improved, and the valve overlap period cannot be extended.

  Therefore, in the first embodiment, the pressure wave is attenuated in order to eliminate and equalize the difference in the internal EGR amount between the cylinders due to the pressure wave of the blowdown gas. The blowdown gas pressure wave attenuating means 8 shown in FIG. 5 is provided, and the blowdown gas attenuated thereby is made to reach another cylinder (blowdown gas inflow cylinder).

Specifically, the blowdown gas pressure wave attenuating means 8 according to the first embodiment is an exhaust path communicating means for communicating the exhaust paths into which exhaust gases from the cylinders # 1 to # 8 flow. exhaust passage 2 _{# 1} from the first exhaust manifold 2 _LH of the fourth in the bank, 2 # _3, 2 # _5, 2 # ₇ and the first pressure wave damping pipe 8 _LH for communicating the exhaust manifold 2 _RH in the right bank first to fourth exhaust passage 2 of _{# 2,} 2 # _4, 2 # _6, 2 and a second pressure wave damping pipe 8 _RH for communicating the # _8, the first pressure wave damping pipe that 8 _LH and the second pressure It is constituted by a communicating pipe 8b for communicating the wave damping pipe 8 _RH.

Here, the first pressure wave attenuating pipe 8 _LH is connected to the first to fourth exhaust passages 2 _{# 1} , 2 _{# 3} , 2 _{# 5} , 2 _{# 7} individually to the first to fourth communication passages. 8 _{# 1} , 8 _{# 3} , 8 _{# 5} , 8 _{# 7} and its first to fourth communication passages 8 _{# 1} , 8 _{# 3} , 8 _{# 5} , 8 _{# 7} is composed of a damping main 8a _1, the second pressure wave damping communicating from a first similarly in the fourth for pipe 8 _RH passages 8 _{# 2,} 8 # _4, 8 # _6, 8 # ₈ and the pressure wave attenuation composed of a main 8a _2.

  Thereby, the blowdown gas inflow cylinders # 6, # 3, # 1, and # 2 whose internal EGR amount increases due to the blowdown gas of the blowdown gas generation cylinders # 4, # 5, # 7, and # 8, respectively. Reaches the blowdown gas attenuated by the blowdown gas pressure wave attenuating means 8. Therefore, the exhaust pulsation difference between the respective cylinders is reduced and the exhaust interference is reduced, so that the internal EGR amount between the cylinders becomes uniform, and the intake air charging efficiency (air-fuel ratio) becomes constant.

For example, the blowdown gas of the seventh cylinder # 7 has its pressure wave attenuated by the blowdown gas pressure wave attenuating means 8 and reaches all the remaining cylinders # 1 to # 6 and # 8 evenly. The exhaust manifolds 2 _LH and 2 _RH are discharged to the downstream exhaust passages (first catalyst devices 3 _LH and 3 _RH, etc.). For this reason, the exhaust interference between the first cylinder # 1 and the seventh cylinder # 7 in which the valve overlap period and the exhaust blowdown timing overlap with each other is reduced, so that the internal EGR amount between the cylinders is reduced. Can be made uniform and the charging efficiency (air-fuel ratio) of the intake air can be made constant.

  As described above, according to the blowdown gas pressure wave attenuating means 8 as in the first embodiment, the exhaust paths of the respective cylinders # 1 to # 8 are in communication with each other. The arrival time of the positive pressure wave of the gas to the other cylinder can be delayed. Therefore, the exhaust pulsation difference between the cylinders # 1 to # 8 can be reduced, and the blowdown gas generating cylinders # 4, # 5, # 7, # 8 and the blowdown gas inflow cylinders # 6, # 3, # Since the exhaust interference between the cylinders 1 and # 2 can be reduced, it is possible to make the internal EGR amount between the respective cylinders uniform and hence the intake air charging efficiency (air-fuel ratio) uniform.

  And since the charging efficiency (air-fuel ratio) of the intake air between the cylinders can be made uniform as described above, the shaft torque can be improved. Further, since the uniform state of the internal EGR amount between the cylinders and the uniform state of the charging efficiency (air-fuel ratio) of the intake air can be maintained even if the valve overlap period is expanded, the valve overlap period As a result, the amount of internal EGR can be increased, and the amount of HC and NOx emissions can be reduced and the fuel consumption rate can be reduced.

The blow-down gas pressure wave attenuating means 8 of the first embodiment has the first to fourth exhaust passages 2 _{# 1} , 2 _{# 3} , 2 _{# 5} , 2 _{# 7} and the right of the exhaust manifold 2 _LH in the left bank. The first to fourth exhaust passages 2 _{# 2} , 2 _{# 4} , 2 _{# 6} , and 2 _{# 8} of the exhaust manifold 2 _RH in the bank are configured to communicate with each other, but the exhaust port 1b _{# 1} in each bank ˜1b _{# 8} may be communicated.

  Next, a second embodiment of the internal combustion engine according to the present invention will be described with reference to FIG. Here, reference numeral 11 in FIG. 4 indicates the internal combustion engine of the second embodiment.

The internal combustion engine 11 of the second embodiment has a cylinder block 11a in which eight cylinders # 1 to # 8 are arranged in the left and right banks and two cylinder heads in the same positional relationship as the internal combustion engine 1 of the first embodiment. This is a V-type 8-cylinder internal combustion engine that includes 11b _LH and 11b _RH , and in which each cylinder # 1 to # 8 is ignited in the same ignition sequence.

The exhaust path of the second embodiment is the same as the exhaust path of the first embodiment, and the exhaust ports 11b _{# 1} , 11b _{# 3} , 11b _{# 5 of the} cylinders # 1, # 3, # 5, # 7 on the left bank side. , 11b _{# 7} , exhaust manifold 12 _LH , first and second catalyst devices 13 _LH , 14 _LH , and first and second exhaust pipes 15 _LH , 16 _LH are provided, and each cylinder # is provided on the right bank side. 2, # 4, # 6, # 8 exhaust ports 11b _{# 2} , 11b _{# 4} , 11b _{# 6} , 11b _{# 8} , exhaust manifold _12RH , first and second catalytic devices _13RH , _{14RH and} first The second exhaust pipes 15 _RH and 16 _RH are provided, and the second exhaust pipes 16 _LH and 16 _RH are combined into one path by the third exhaust pipe 17. These do not necessarily have to be combined into one path by the third exhaust pipe 17. Further, the first exhaust pipes 15 _LH and 15 _RH are gathered in one path, and one catalyst device is arranged in place of the two second catalyst devices 14 _LH and 14 _RH on the downstream side of the gathered portion. May be.

Here, in the second embodiment, the types of the exhaust manifolds 12 _LH and 12 _RH are changed as follows.

First, as shown in FIG. 4, the exhaust manifold 12 _{LH in} the left bank of the second embodiment is connected to the exhaust ports 11b _{# 1} , 11b _{# 3} , 11b _{# 5} , and 11b _{# 7} individually as shown in FIG. 4 exhaust passages 12 _{# 1} , 12 _{# 3} , 12 _{# 5} , 12 _{# 7} and the first collecting passage for collecting the exhaust gases of the first and second exhaust passages 12 _{# 1} , 12 _{# 3} in one path 12a ₁ , a second collecting passage 12b ₁ for collecting the exhaust gases of the third and fourth exhaust passages 12 _{# 5} and 12 _{# 7} in one path, and the first and second collecting passages 12a ₁ and 12b _And a third collecting passage 12c ₁ for collecting one exhaust gas in one path.

On the other hand, the exhaust manifold 12 _RH of the right bank, as shown in FIG. 4, the exhaust port 11b of the respective _{# 2, 11b # 4, 11b} # 6, 11b # 8 and an exhaust passage 12 individually from a first communicating fourth _# 2, 12 _# 4, 12 _# 6, 12 _{# 8,} a first collecting passage 12a ₂ to assemble the first and second exhaust passages ₁₂ # 2, 12 _{# 4} of the exhaust gas to one path, the The second collecting passage 12b ₂ for collecting the exhaust gases of the third and fourth exhaust passages 12 _{# 6} and 12 _{# 8} in one path, and the exhaust gas of the first and second collecting passages 12a ₂ and 12b ₂ are collected. It is composed of a third collecting passage 12c ₂ that collects in one route.

That is, the so-called 4-1 type exhaust manifolds 2 _LH and 2 _RH are used in the internal combustion engine 1 of the first embodiment, but in the second embodiment, the so-called 4-2-1 type exhaust manifold 12 _{LH is used.} , 12 _RH is used.

By the way, even when the shapes of the exhaust manifolds 12 _LH and 12 _RH are different as described above, exhaust interference due to the influence of blowdown gas occurs between the same cylinders as in the first embodiment.

For this reason, even in the second embodiment, as in the first embodiment, the first to fourth exhaust passages 12 _{# 1} , 12 _{# 3} , 12 _{# 5} , 12 _{# 7} in the exhaust manifold 12 _LH of the left bank. And the first to fourth exhaust passages 12 _{# 2} , 12 _{# 4} , 12 _{# 6} , and 12 _{# 8} in the exhaust manifold _12RH of the right bank are provided with blowdown gas pressure wave attenuating means 18, respectively.

Here, the blowdown gas pressure wave attenuating means 18 of the second embodiment is similar to the first to fourth communication passages 18 _{# 1} , 18 _{# 3} , 18 _{# 5} , 18 _{# 8} and pressure. a first pressure wave attenuation tube 18 _LH consisting wave attenuation main 18a _1, first the first consisting of the fourth communication passage 18 _# 2, 18 _# 4, 18 _# 6, 18 _{# 7} and the pressure wave damping main 18a ₂ and second pressure wave damping pipe 18 _RH, is composed of a first pressure wave attenuation tube 18 _LH and communication pipe 18b communicating the second pressure wave damping pipe 18 _RH.

  Thereby, the blowdown gas inflow cylinders # 6, # 3, # 1, and # 2 whose internal EGR amount increases due to the blowdown gas of the blowdown gas generation cylinders # 4, # 5, # 7, and # 8, respectively. In the same manner as in the first embodiment, the blowdown gas attenuated by the blowdown gas pressure wave attenuation means 18 arrives. Therefore, the exhaust pulsation difference between the respective cylinders is reduced and the exhaust interference is reduced, so that the internal EGR amount between the cylinders becomes uniform, and the intake air charging efficiency (air-fuel ratio) becomes constant.

  That is, according to the blowdown gas pressure wave attenuating means 18 of the second embodiment, the blowdown gas is attenuated as in the first embodiment, and the positive pressure wave of the blowdown gas reaches the other cylinder. Can be delayed. Therefore, the exhaust pulsation difference between the cylinders # 1 to # 8 can be reduced, and the blowdown gas generating cylinders # 4, # 5, # 7, # 8 and the blowdown gas inflow cylinders # 6, # 3, # Since the exhaust interference between the cylinders 1 and # 2 can be reduced, it is possible to make the internal EGR amount between the respective cylinders uniform and hence the intake air charging efficiency (air-fuel ratio) uniform.

  And since the charging efficiency (air-fuel ratio) of the intake air between the cylinders can be made uniform as described above, the shaft torque can be improved. Further, since the uniform state of the internal EGR amount between the cylinders and the uniform state of the charging efficiency (air-fuel ratio) of the intake air can be maintained even if the valve overlap period is expanded, the valve overlap period As a result, the amount of internal EGR can be increased, and the amount of HC and NOx emissions can be reduced and the fuel consumption rate can be reduced.

Even in the second embodiment, the blow-down gas pressure wave attenuating means 18 may be configured to communicate the exhaust ports 11b _{# 1 to} 11b _{# 8} in the left and right banks.

  Next, a third embodiment of the internal combustion engine according to the present invention will be described with reference to FIG. Here, reference numeral 21 in FIG. 5 indicates the internal combustion engine of the third embodiment.

The internal combustion engine 21 of the third embodiment includes a cylinder block 21a in which eight cylinders # 1 to # 8 are arranged in the left and right banks and two cylinder heads in the same positional relationship as the internal combustion engine 1 of the first embodiment. This is a V-type 8-cylinder internal combustion engine that includes 21b _LH and 21b _RH , and in which each cylinder # 1 to # 8 is ignited in the same ignition sequence.

Also in the exhaust path of the third embodiment, on the left bank side, exhaust ports 21b _{# 1} , 21b _{# 3} , 21b _{# 5} , 21b _{# 7} , exhaust manifold 22 of each cylinder # 1, # 3, # 5, # 7 are provided. _LH , first and second catalyst devices 23 _LH and 24 _LH , and first and second exhaust pipes 25 _LH and 26 _LH are provided, and each cylinder # 2, # 4, # 6 is provided on the right bank side. , # 8 exhaust ports 21b _{# 2} , 21b _{# 4} , 21b _{# 6} , 21b _{# 8} , exhaust manifold _22RH , first and second catalyst devices _23RH , _24RH and first and second exhaust pipes 25 _RH and 26 _RH are provided, and the second exhaust pipes 26 _LH and 26 _RH are _grouped in one path by the third exhaust pipe 27. These do not necessarily have to be combined into one path by the third exhaust pipe 27. Further, the first exhaust pipes 25 _LH and 25 _RH are gathered in one path, and one catalyst device is arranged in place of the two second catalyst devices 24 _LH and 24 _RH on the downstream side of the gathered portion. May be.

Here, as the exhaust manifolds 22 _LH and 22 _RH of the third embodiment, the same 4-1 type as in the first embodiment is used, and the first catalyst device is provided immediately after each of the exhaust manifolds 22 _LH and 22 _RH. It is assumed that 23 _LH and 23 _RH are deployed.

That is, in the left bank side, the exhaust passage 22 _# 1 of the first to fourth, 22 _# 3, 22 _# 5, 22 _{# 7} and the exhaust manifold 22 _LH in the manifolds 22a ₁ is formed, the manifolds 22a first catalyzer 23 _LH is provided at the downstream end of _1. On the other hand, in the right-bank # 2 from the first fourth exhaust passage _22, 22 _# 4, 22 _# 6, 22 _RH exhaust manifold 22 at _{# 8} and manifolds 22a ₂ is configured, the manifolds 22a The first catalytic device 23 _RH is provided at the downstream end of ₂ .

Further, in the third embodiment, the exhaust paths of the respective banks are communicated using the communication pipes 28 shown in FIG. 5 in front of the first catalyst devices 23 _LH and 23 _RH . Specifically, as shown in FIG. 5, a communication pipe 28 communicates the vicinity of the downstream end of the left bank side collecting passage 22 a _{1 and} the vicinity of the downstream end of the right bank side collecting passage 22 a ₂ .

  The communication pipe 28 functions as a blowdown gas pressure wave attenuation means for attenuating the pressure wave of the blowdown gas, whereby the blowdown gas generating cylinders # 4, # 5, # 7, and # 8 are blown down. Blowdown gas attenuated by passing through the communication pipe 28 reaches the blowdown gas inflow cylinders # 6, # 3, # 1, and # 2 in which the internal EGR amount increases due to the gas. Therefore, the exhaust pulsation difference between the respective cylinders is reduced and the exhaust interference is reduced, so that the internal EGR amount between the cylinders is made uniform and the intake air charging efficiency (air-fuel ratio) becomes constant.

For example, the blowdown gas of the seventh cylinder # 7 reaches all of the remaining cylinders # 1 to # 6, # 8, while being connected to the downstream exhaust path (the first exhaust _passage ) via the respective exhaust manifolds _22LH , _22RH . 1 catalyst device 23 _LH , 23 _RH, etc.). For this reason, the exhaust interference between the first cylinder # 1 and the seventh cylinder # 7 where the valve overlap period and the exhaust blowdown timing overlap is reduced, and the internal EGR amount between the cylinders is made uniform. As a result, the charging efficiency (air-fuel ratio) of the intake air becomes constant.

In this way, by providing the communication pipe 28 in front of the first catalyst devices 23 _LH and 23 _RH , the blowdown gas is attenuated, and the arrival time of the positive pressure wave of the blowdown gas to the other cylinder is delayed. Can do. Therefore, the exhaust pulsation difference between the cylinders # 1 to # 8 can be reduced, and the internal EGR amount is affected by the blowdown gas generating cylinders # 4, # 5, # 7, # 8 and their respective blowdown gases. This makes it possible to reduce the exhaust interference between the blowdown gas inflow cylinders # 6, # 3, # 1, and # 2, so that the amount of internal EGR between the cylinders and the intake air can be reduced. It is possible to make the charging efficiency (air-fuel ratio) uniform.

  And since the charging efficiency (air-fuel ratio) of the intake air between the cylinders can be made uniform as described above, the shaft torque can be improved. Further, since the uniform state of the internal EGR amount between the cylinders and the uniform state of the charging efficiency (air-fuel ratio) of the intake air can be maintained even if the valve overlap period is expanded, the valve overlap period As a result, the amount of internal EGR can be increased, and the amount of HC and NOx emissions can be reduced and the fuel consumption rate can be reduced.

In addition to the communication pipe 28 described above, the left and right first exhaust pipes 25 _LH and 25 _RH may be made to communicate with each other through another communication pipe, thereby further increasing the exhaust pulsation difference between the cylinders # 1 to # 8. The internal EGR amount, and hence the intake air charging efficiency (air-fuel ratio) can be made uniform.

  Here, the blowdown gas pressure wave attenuating means 8 as in the first embodiment may be applied to the internal combustion engine 21 of the third embodiment, thereby more effectively reducing the exhaust interference between the cylinders. Thus, the internal EGR amount between the cylinders, and hence the intake air charging efficiency (air-fuel ratio) can be effectively equalized.

  Next, a fourth embodiment of the internal combustion engine according to the present invention will be described with reference to FIG. Here, reference numeral 31 in FIG. 6 indicates the internal combustion engine of the fourth embodiment.

The internal combustion engine 31 of the fourth embodiment has a cylinder block 31a in which eight cylinders # 1 to # 8 are arranged in the left and right banks and two cylinder heads in the same positional relationship as the internal combustion engine 11 of the second embodiment. This is a V-type 8-cylinder internal combustion engine that includes 31b _LH and 31b _RH , and in which each cylinder # 1 to # 8 is ignited in the same ignition sequence.

Even in the fourth embodiment, on the left bank side, the exhaust ports 31b _{# 1} , 31b _{# 3} , 31b _{# 5} , 31b _{# 7} of each cylinder # 1, # 3, # 5, _{# 7} , exhaust manifold 32 _LH , First and second catalyst devices 33 _LH , 34 _LH and first and second exhaust pipes 35 _LH , 36 _LH are provided, and each cylinder # 2, # 4, # 6 is provided on the right bank side. # 8 exhaust ports 31b _{# 2} , 31b _{# 4} , 31b _{# 6} , 31b _{# 8} , exhaust manifold _32RH , first and second catalytic devices _33RH , _34RH , and first and second exhaust pipes _35RH , 36 _RH are provided, and the second exhaust pipes 36 _LH , 36 _RH are _grouped in one path by the third exhaust pipe 37. These do not necessarily have to be combined into one path by the third exhaust pipe 37. Further, the first exhaust pipes 35 _LH and 35 _RH are gathered in one path, and one catalyst device is arranged in place of the two second catalyst devices 34 _LH and 34 _RH on the downstream side of the gathered portion. May be.

Here, as the exhaust manifolds 32 _LH and 32 _RH of the fourth embodiment, the same 4-2-1 type as in the second embodiment is used, and the first one immediately after the respective exhaust manifolds 32 _LH and 32 _RH . It is assumed that catalyst devices 33 _LH and 33 _RH are installed.

That is, on the left bank side, the first to fourth exhaust passages 32 _{# 1} , 32 _{# 3} , 32 _{# 5} , 32 _{# 7} and the first to third collective passages 32 a ₁ , 32 b ₁ , 32 c ₁ An exhaust manifold 32 _LH is configured, and a first catalyst device 33 _LH is provided at the downstream end of the third collecting passage 32 c ₁ . On the other hand, in the right-bank, in the first and fourth exhaust passage ₃₂ # 2, 32 _# 4, 32 _# 6, 32 _{# 8} from the first third manifolds 32a _2, 32 b _2, 32c _{2 RH} exhaust manifold 32 is configured, _RH first catalyzer 33 is provided in the third downstream end manifolds 32c _2.

Also in the fourth embodiment, similarly to the third embodiment described above, the exhaust paths of the respective banks are _arranged in front of the first catalyst devices 33 _LH and 33 _RH (that is, the respective third collecting passages 32c). ₁ and 32c _{2 in} the vicinity of the downstream end) using a communication pipe 38 shown in FIG.

  This communication pipe 38 functions as a blow-down gas pressure wave attenuating means as in the third embodiment, so that the exhaust pulsation difference between the cylinders # 1 to # 8 can be reduced. As a result, the internal EGR amount between the cylinders, and hence the intake air charging efficiency (air-fuel ratio) can be made uniform.

  And since the charging efficiency (air-fuel ratio) of the intake air between the cylinders can be made uniform as described above, the shaft torque can be improved. Further, since the uniform state of the internal EGR amount between the cylinders and the uniform state of the charging efficiency (air-fuel ratio) of the intake air can be maintained even if the valve overlap period is expanded, the valve overlap period As a result, the amount of internal EGR can be increased, and the amount of HC and NOx emissions can be reduced and the fuel consumption rate can be reduced.

In the fourth embodiment, in addition to the communication pipe 38 described above, the first exhaust pipes 35 _LH and 35 _RH may be communicated with other communication pipes. By reducing the exhaust pulsation difference between 1 and # 8, the internal EGR amount, and thus the intake air charging efficiency (air-fuel ratio) can be made uniform.

  Here, the blow-down gas pressure wave attenuating means 18 as in the second embodiment may be applied to the internal combustion engine 31 of the fourth embodiment, thereby more effectively reducing the exhaust interference between the cylinders. Thus, the internal EGR amount between the cylinders, and hence the intake air charging efficiency (air-fuel ratio) can be effectively equalized.

  Next, a fifth embodiment of the internal combustion engine according to the present invention will be described with reference to FIG. Here, reference numeral 41 in FIG. 7 indicates the internal combustion engine of the fifth embodiment.

The internal combustion engine 41 of the fifth embodiment has a cylinder block 41a in which eight cylinders # 1 to # 8 are arranged in the left and right banks in the same positional relationship as the internal combustion engine 1 of the first embodiment and two cylinder heads. This is a V-type 8-cylinder internal combustion engine that includes 41b _LH and 41b _RH , and in which each cylinder # 1 to # 8 is ignited in the same firing order.

Even in the fifth embodiment, on the left bank side, the exhaust ports 41b _{# 1} , 41b _{# 3} , 41b _{# 5} , 41b _{# 7} of each cylinder # 1, # 3, # 5, _{# 7} , exhaust manifold 42 _LH , First and second catalyst devices 43 _LH , 44 _LH and first and second exhaust pipes 45 _LH , 46 _LH are provided, and each cylinder # 2, # 4, # 6 is provided on the right bank side. # 8 exhaust ports 41b _{# 2} , 41b _{# 4} , 41b _{# 6} , 41b _{# 8} , exhaust manifold _42RH , first and second catalytic devices _43RH , _44RH and first and second exhaust pipes _45RH , 46 _RH are provided, and the second exhaust pipes 46 _LH , 46 _RH are _grouped in one path by the third exhaust pipe 47. These do not necessarily have to be combined into one path by the third exhaust pipe 47. Further, the first exhaust pipes 45 _LH and 45 _RH are gathered in one path, and one catalyst device is arranged on the downstream side of the gathered portion instead of the two second catalyst devices 44 _LH and 44 _RH. May be.

In the fifth embodiment, the first to fourth exhaust passages 42 _{# 1} , 42 _{# 3} , which communicate with the exhaust ports 41 b _{# 1} , 41 b _{# 3} , 41 b _{# 5} , 41 b _{# 7} of the left bank individually. 42 _{# 5} and 42 _{# 7} , a large-capacity exhaust collecting chamber 42a ₁ into which the exhaust gases of the first to fourth exhaust passages 42 _{# 1} , 42 _{# 3} , 42 _{# 5} and 42 _{# 7} flow in, and this An exhaust manifold 42 _LH of the left bank is constituted by a collecting passage 42b ₁ that communicates with the exhaust collecting chamber 42a ₁ and connects the first catalyst device 43 _LH to the downstream end side.

Similarly, the exhaust manifold 42 _RH of the right bank, the exhaust port 41b of the left bank _# 2, 41b _# 4, 41b _# 6, 41b _{# 8} and individual exhaust from the first communicating the fourth to passage 42 _{# 2} , 42 _{# 4} , 42 _{# 6} , 42 _{# 8,} and a large-capacity exhaust chamber into which the exhaust gases in the first to fourth exhaust passages 42 _{# 2} , 42 _{# 4} , 42 _{# 6} , 42 _{# 8} flow. 42a ₂ and a collecting passage 42b ₂ which communicates with the exhaust collecting chamber 42a ₂ and connects the first catalyst device _43RH to the downstream end side.

Here, the internal capacity of the exhaust manifolds 42a ₁ and 42a ₂ in the respective exhaust manifolds 42 _LH and 42 _RH is increased by, for example, making the diameter larger than the pipe diameters of the exhaust passages 42 _{# 1 to} 42 _{# 8.} To do.

Thereby, the blowdown gas inflow cylinders # 6, # 3, # 1, and # 2 whose internal EGR amount increases due to the blowdown gas of the blowdown gas generation cylinders # 4, # 5, # 7, and # 8, respectively. Reaches the blowdown gas attenuated in the respective exhaust collecting chambers 42a ₁ and 42a ₂ . That is, in the fifth embodiment, the exhaust collecting chambers 42a ₁ and 42a ₂ function as blow-down gas pressure wave attenuating means, and the exhaust collecting chambers 42a ₁ and 42a ₂ exhaust the exhaust gas between the respective cylinders. The pulsation difference is reduced to reduce exhaust interference, the internal EGR amount between the cylinders is made uniform, and the intake air charging efficiency (air-fuel ratio) is made constant.

For example, blowdown gas 7 cylinder # 7, the after pressure wave is attenuated in the exhaust collecting chamber 42a _1, since reaching the No. 1 cylinder # 1, 3 cylinder # 3 and the fifth cylinder # 5 The exhaust interference between the first cylinder # 1 and the seventh cylinder # 7, where the valve overlap period and the exhaust blowdown timing overlap, is reduced, and the internal EGR amount between the cylinders is made uniform and suctioned. The air charging efficiency (air-fuel ratio) becomes constant.

Thus, by providing the exhaust collecting chamber 42a _1, 42a ₂ of the large-capacity exhaust manifold 42 _LH, 42 _RH each as in the present embodiment 5, attenuates the blowdown gas positive pressure wave of the blowdown gas The arrival time to the other cylinder can be delayed. Therefore, the exhaust pulsation difference between the cylinders # 1, # 3, # 5, and # 7 in the left bank and the exhaust pulsation difference between the cylinders # 2, # 4, # 6, and # 8 in the right bank are reduced. Blowdown gas generating cylinders # 4, # 5, # 7, and # 8 and blowdown gas inflow cylinders # 6, # 3, # 1, and # 8 whose internal EGR amount increases due to their respective blowdown gases Therefore, it is possible to reduce the internal EGR amount between the respective cylinders, and hence the intake air charging efficiency (air-fuel ratio).

  And since the charging efficiency (air-fuel ratio) of the intake air between the cylinders can be made uniform as described above, the shaft torque can be improved. Further, since the uniform state of the internal EGR amount between the cylinders and the uniform state of the charging efficiency (air-fuel ratio) of the intake air can be maintained even if the valve overlap period is expanded, the valve overlap period As a result, the amount of internal EGR can be increased, and the amount of HC and NOx emissions can be reduced and the fuel consumption rate can be reduced.

  Here, the blowdown gas pressure wave attenuating means 18 as in the second embodiment and / or the communication pipe 38 as in the fourth embodiment may be applied to the internal combustion engine 41 of the fifth embodiment, which makes it more effective. Further, it is possible to reduce the exhaust interference between the cylinders, and to effectively equalize the internal EGR amount between the cylinders, and hence the intake air charging efficiency (air-fuel ratio).

  Next, a sixth embodiment of the internal combustion engine according to the present invention will be described with reference to FIG. Here, reference numeral 51 in FIG. 8 indicates the internal combustion engine of the sixth embodiment.

The internal combustion engine 51 of the sixth embodiment has eight cylinders # 1 to # 8 in left and right banks in the same positional relationship as the internal combustion engines 1, 11, 21, 31, and 41 of the first to fifth embodiments. This is a V-type 8-cylinder internal combustion engine that includes a cylinder block 51a and two cylinder heads 51b _LH and 51b _RH, and each of the cylinders # 1 to # 8 is ignited in the same ignition order.

  Even in the sixth embodiment, an exhaust manifold 52 is provided as shown in FIG. 8, and the first and second catalyst devices 53, 54 and the first and second catalyst devices 53, 54 are provided downstream thereof. A first exhaust pipe 55 that communicates with the second exhaust pipe 55 and a second exhaust pipe 56 into which exhaust gas that has passed through the second catalytic device 54 flows are provided.

The exhaust manifold 52 of the sixth embodiment, the exhaust passage 52 _# 1-52 _{# 8} of the exhaust port 51b _# 1 ～51B _{# 8} and first to eighth communicating individually for each cylinder # 1 to # 8, The first to eighth exhaust passages 52 _{# 1 to} 52 _{# 8} have large-capacity exhaust collective chambers 52a into which exhaust gas flows, and communicate with the exhaust collective chambers 52a. And a collecting passage 52b for connecting the two to the left and right banks.

Here, the internal capacity of the exhaust collecting chamber 52a is increased by making it larger than the pipe diameters of the exhaust passages 52 _{# 1 to} 52 _{# 8} , for example.

  Thereby, the blowdown gas inflow cylinders # 6, # 3, # 1, and # 2 whose internal EGR amount increases due to the blowdown gas of the blowdown gas generation cylinders # 4, # 5, # 7, and # 8, respectively. The blow-down gas attenuated by the exhaust collecting chamber 52a reaches evenly. For this reason, the exhaust pulsation difference between the cylinders # 1 to # 8 is reduced and the exhaust interference is reduced, so that the internal EGR amount between the cylinders is made uniform and the intake air charging efficiency (air-fuel ratio) is constant. become.

  For example, the blowdown gas of the seventh cylinder # 7 reaches all the remaining cylinders # 1 to # 6 and # 8 after the pressure wave is attenuated in the exhaust collecting chamber 52a. Exhaust interference between the first cylinder # 1 and the seventh cylinder # 7 where the exhaust blowdown timing and the exhaust blowdown timing overlap is reduced, the internal EGR amount between the cylinders is made uniform, and the intake air charging efficiency ( The air / fuel ratio becomes constant.

  That is, the large-capacity exhaust collecting chamber 52a functions as a blowdown gas pressure wave attenuating means for attenuating the pressure wave of the blowdown gas to reach the other cylinders, as in the fifth embodiment. The blowdown gas can be attenuated and the arrival time of the blowdown gas to the other cylinder can be delayed. Therefore, the exhaust pulsation difference between the cylinders # 1 to # 8 can be reduced, and the blowdown gas generating cylinders # 4, # 5, # 7, # 8 and the blowdown gas inflow cylinders # 6, # 3, # Since the exhaust interference between the cylinders 1 and # 2 can be reduced, it is possible to make the internal EGR amount between the respective cylinders uniform and hence the intake air charging efficiency (air-fuel ratio) uniform.

  And since the charging efficiency (air-fuel ratio) of the intake air between the cylinders can be made uniform as described above, the shaft torque can be improved. Further, since the uniform state of the internal EGR amount between the cylinders and the uniform state of the charging efficiency (air-fuel ratio) of the intake air can be maintained even if the valve overlap period is expanded, the valve overlap period As a result, the amount of internal EGR can be increased, and the amount of HC and NOx emissions can be reduced and the fuel consumption rate can be reduced.

Further, since the exhaust manifold 52 is disposed between the left and right banks as in the sixth embodiment, heat can be trapped between the banks and the warm-up performance of the internal combustion engine 51 can be improved. Furthermore, according to the exhaust manifold 52 having such an arrangement, the exhaust gas can be collected in the exhaust collecting chamber 52a at a position close to the respective cylinder heads 51b _LH and 51b _RH. The performance is improved and the emission performance immediately after the engine is started can be improved.

  Here, the blowdown gas pressure wave attenuating means 8 and 18 as in the first and second embodiments may be applied to the internal combustion engine 51 of the sixth embodiment, thereby more effectively exhaust interference between the respective cylinders. Therefore, the internal EGR amount between the cylinders, and thus the intake air charging efficiency (air-fuel ratio) can be effectively equalized.

  Next, a seventh embodiment of the internal combustion engine according to the present invention will be described with reference to FIG. Here, reference numeral 61 in FIG. 9 indicates the internal combustion engine of the seventh embodiment.

The internal combustion engine 21 of the seventh embodiment has eight cylinders # 1 to ## in left and right banks in the same positional relationship as the internal combustion engines 1, 11, 21, 31, 41, 51 of the first to sixth embodiments. 8 is a V-type 8-cylinder internal combustion engine that includes a cylinder block 61a in which 8 is disposed and two cylinder heads 61b _LH and 61b _RH, and each of the cylinders # 1 to # 8 is ignited in the same firing order.

In the present embodiment 7, an exhaust port 61b _# 1 ~61b _{# 8} of each cylinder # 1 to # 8, and two exhaust manifold 62 _LH, 62 _RH disposed between the left and right respective banks, each The first catalyst devices 63 _LH and 63 _RH arranged on the downstream side of the exhaust manifolds 62 _LH and 62 _RH , and the first exhaust pipe 64 _LH into which exhaust gas having passed through the first catalyst devices 63 _LH and 63 _RH flows, respectively. , 64 _RH , a first exhaust pipe 64 _LH , a second exhaust pipe 65 that collects the exhaust gas of 64 _RH in one path, a second catalyst device 66 into which the exhaust gas that has passed through the second exhaust pipe 65 flows, An exhaust path is constituted by the third exhaust pipe 67 into which the exhaust gas that has passed through the second catalyst device 66 flows.

  Here, as described in the first embodiment, also in the V-type eight-cylinder internal combustion engine 61 of the seventh embodiment, the first cylinder # 1 and the seventh cylinder # 7, the third cylinder # 3 and the fifth cylinder # If the fifth and sixth cylinders # 6, # 4, # 2, # 2 and # 8 communicate with one exhaust manifold, the first cylinder # 1, third cylinder # 3, 6 When No. # 6 or No. 2 # 2 is in the valve overlap period, due to the effect of blowdown gas of No. 7 cylinder # 7, No. 5 cylinder # 5, No. 4 cylinder # 4 or No. 8 cylinder # 8, respectively Exhaust interference can occur between the cylinders.

Therefore, in the seventh embodiment, the blowdown gas generating cylinders # 4, # 5, # 7, and # 8 and the blowdown gas inflow cylinder # in which the internal EGR amount increases due to the influence of the respective blowdown gases. The two exhaust manifolds 62 _LH and 62 _RH are formed in a shape that does not allow communication between 6, # 3, # 1, and # 2.

For example, as shown in FIG. 9, the exhaust ports 61b _{# 1} , 61b _{# 3} , 61b _{# 4} , 61b _{# 8 of} the first cylinder # 1, the third cylinder # 3, the fourth cylinder # 4 and the eighth cylinder # 8 The first to fourth exhaust passages 62 _{# 1} , 62 _{# 3} , 62 _{# 4} , 62 _{# 8} and the first to fourth exhaust passages 62 _{# 1} , 62 _{# 3} , 62 _{# 4} , One exhaust manifold 62 _LH is constituted by the collecting passage 62a ₁ for collecting the exhaust gas 62 _{# 8} in one path. Then, for the other exhaust manifold 62 _RH, communicating with each exhaust port _{61b # 2, 61b # 5 ~61b} # 7 of the remaining second cylinder # 7 from No. 2 and No. 5 cylinder cylinder # 5 to # 7 The first to fourth exhaust passages 62 _{# 2} and 62 _{# 5 to} 62 _{# 7} and the exhaust gases of the first to fourth exhaust passages 62 _{# 2} and 62 _{# 5 to} 62 _{# 7} are collected in one path. composed of the manifolds 62a _2.

Here, according to the exhaust manifold 62 _LH and the exhaust manifold 62 _RH , the blowdown gas generating cylinders # 4 and # 4 that affect the cylinders # 6, # 3, # 1, and # 2 in the valve overlap period. The exhaust passages 62 _{# 4} , 62 _{# 5} , 62 _{# 7} and 62 _{# 8} of _{# 5} , _{# 7} and _{# 8} are blown extending to the collecting passages 62a ₁ and 62a ₂ arranged on the opposite bank side, respectively. Down gas exhaust path extension structure. For this reason, the pressure wave of the blow-down gas is attenuated while flowing through the exhaust passages 62 _{# 4} , 62 _{# 5} , 62 _{# 7} , 62 _{# 8} .

  Further, for example, the blowdown gas in the seventh cylinder # 7 reaches the cylinders # 2, # 5, and # 6 in which the exhaust valves are closed, but the first cylinder # 1 in which the exhaust valves are opened. Therefore, the exhaust interference between the first cylinder # 1 and the seventh cylinder # 7 where the valve overlap period and the exhaust blowdown timing overlap is suppressed, and the internal EGR amount between the cylinders is suppressed. Can be made uniform and the charging efficiency (air-fuel ratio) of the intake air can be made constant.

As described above, the exhaust manifolds 62 _LH and 62 _RH of the seventh embodiment function as blowdown gas pressure wave attenuation means for attenuating the pressure wave of the blowdown gas, while the blowdown gas generating cylinders # 4 and # 5 are used. , # 7, # 8 and blowdown gas inflow cylinders # 6, # 3, # 1, # 2 are not communicated with each other. For this reason, exhaust interference between the cylinders # 1 to # 8 can be suppressed, so that the internal EGR amount between the cylinders, and hence the intake air charging efficiency (air-fuel ratio) can be made uniform.

  And since the charging efficiency (air-fuel ratio) of the intake air between the cylinders can be made uniform as described above, the shaft torque can be improved. Further, since the uniform state of the internal EGR amount between the cylinders and the uniform state of the charging efficiency (air-fuel ratio) of the intake air can be maintained even if the valve overlap period is expanded, the valve overlap period As a result, the amount of internal EGR can be increased, and the amount of HC and NOx emissions can be reduced and the fuel consumption rate can be reduced.

Further, since the exhaust manifold 62 _LH, 62 _RH as in the present embodiment 7 is disposed between the left and right respective banks, to improve the warm-up performance of the internal combustion engine 61 by Komora heat between that bank it can.

  Here, the blowdown gas pressure wave attenuating means 8 and 18 as in the first and second embodiments may be applied to the internal combustion engine 61 of the seventh embodiment, thereby more effectively exhaust interference between the cylinders. Thus, the internal EGR amount between the cylinders, and hence the intake air charging efficiency (air-fuel ratio) can be effectively equalized.

  Next, an internal combustion engine according to an eighth embodiment of the present invention will be described with reference to FIGS. Here, reference numeral 71 in FIG. 10 indicates the internal combustion engine of the eighth embodiment.

The internal combustion engine 71 of the eighth embodiment has a cylinder block 71a in which eight cylinders # 1 to # 8 are arranged in the left and right banks in the same positional relationship as the internal combustion engine 1 of the first embodiment and two cylinder heads. This is a V-type 8-cylinder internal combustion engine that includes 71b _LH and 71b _RH , and in which each cylinder # 1 to # 8 is ignited in the same ignition sequence.

Even in the eighth embodiment, on the left bank side, exhaust ports 71b _{# 1} , 71b _{# 3} , 71b _{# 5} , 71b _{# 7} of each cylinder # 1, # 3, # 5, _{# 7} , exhaust manifold 72 _LH , First and second catalyst devices 73 _LH , 74 _LH and first and second exhaust pipes 75 _LH , 76 _LH are provided, and each cylinder # 2, # 4, # 6 is provided on the right bank side. # 8 exhaust ports 71b _{# 2} , 71b _{# 4} , 71b _{# 6} , 71b _{# 8} , exhaust manifold _72RH , first and second catalyst devices _73RH , _74RH , and first and second exhaust pipes _75RH , 76 _RH are provided, and the respective second exhaust pipes 76 _LH , 76 _RH are collected in one path by the third exhaust pipe 77. Note that these are not necessarily combined into one path by the third exhaust pipe 77. Further, the first exhaust pipes 75 _LH and 75 _RH are gathered in one path, and one catalyst device is arranged in place of the two second catalyst devices 74 _LH and 74 _RH on the downstream side of the gathered portion. May be.

Here, as the exhaust manifolds 72 _LH and 72 _RH of the eighth embodiment, the same 4-1 type as in the first embodiment is used. That is, on the left bank side, the first to fourth exhaust passages 72 _{# 1} , 72 _{# 3} , 72 _{# 5} , 72 _{# 7} and the collecting passage 72a ₁ constitute an exhaust manifold 72 _LH , and the right bank side an exhaust manifold 72 _RH at a set passage 72a ₂ and the fourth exhaust passage ₇₂ # 2, 72 _# 4, 72 _# 6, 72 _{# 8} from the first is constituted in.

  By the way, as described in the first embodiment, even in the V-type eight-cylinder internal combustion engine 71 of the eighth embodiment, if the valve overlap period is set, the first cylinder # 1, the third cylinder # 3, and the sixth cylinder When the cylinder # 6 and the second cylinder # 2 are in the valve overlap period, due to the influence of the blowdown gas of the seventh cylinder # 7, fifth cylinder # 5, fourth cylinder # 4 and eighth cylinder # 8, respectively. Exhaust interference can occur between the cylinders.

Therefore, in the eighth embodiment, blow-down gas pressure wave attenuating means 78 _LH and 78 _RH for attenuating the pressure wave of the blow-down gas are provided in the left and right banks, respectively.

The blowdown gas pressure wave attenuating means 78 _LH and 78 _RH of the eighth embodiment is blown down during the valve overlap period of the first cylinder # 1, the third cylinder # 3, the sixth cylinder # 6 and the second cylinder # 2. Blowdown gas exhaust that extends the exhaust gas flow paths of the seventh cylinder # 7, fifth cylinder # 5, fourth cylinder # 4, and eighth cylinder # 8 that generate gas and attenuates the pressure wave of the blowdown gas It is a route extension structure.

Specifically, the blowdown gas pressure wave attenuating means 78 _LH and 78 _RH are respectively connected to the exhaust paths through which the blowdown gas from the blowdown gas generating cylinders # 4, # 5, # 7, and # 8 flows and the respective exhaust paths. The amount of internal EGR is increased due to the blowdown gas of the blowdown gas. The blowdown gas flows downstream from the respective exhaust paths through which the exhaust gas from the blowdown gas inflow cylinders # 6, # 3, # 1, and # 2 flows. Bypass passages for bypassing to the exhaust path on the side are provided.

First, regarding the blow-down gas pressure wave attenuating means 78 _LH of the left bank, the collecting passage 72a ₁ of the exhaust manifold 72 _LH in the left bank is joined with the first and second exhaust passages 72 _{# 1} and 72 _{# 3.} than the part divided into a first divided path 72a ₁₁ at the upstream side of the merging portion between the third and fourth exhaust passage 72 # _5, 72 # ₇ and the downstream side and the second divided path 72a _12. Then, while communicating the two openings of the flow path switching valve 78A ₁ with three openings in the respective first and second divided path 72a _11, 72a _12, and the remainder of the opening and the first exhaust pipe 75 _LH It communicates with the bypass passage 78B ₁ and configure.

For example, as the flow path switching valve 78A ₁ , the first state where the first and second division paths 72a ₁₁ and 72a ₁₂ communicate with each other and the opening on the bypass path 78B ₁ side is closed, and the first division path 72 a ₁₁ , the second dividing path 72 a _12, and the bypass passage 78 B ₁ communicate with each other (that is, switch the second state in which three openings are open).

On the other hand, similarly the blowdown gas pressure wave damping means 78 _RH in the right bank, an exhaust manifold 72 _RH manifolds 72a _2, the joining portion between the first and second exhaust passages 72 # _2, 72 # ₄ Is divided into a first divided path 72a ₂₁ and a second divided path 72a ₂₂ on the downstream side and upstream of the merged portion of the third and fourth exhaust passages 72 _{# 6} and 72 _{# 8} . and second divided path 72a _11, 72a ₁₂ and one to communicate each connecting two openings of the flow path switching valve 78A ₂ having three apertures, the bypass passage 78B ₂ and the remainder of the opening and the first exhaust pipe 75 _RH And communicate with each other.

For even channel switching valve 78A ₂ of the right bank, use shall be at similar passage switching the flow path switching valve 78A ₁ of the left bank. That is, the flow path switching valve 78A ₂ includes a first state in which the first and second division paths 72a ₂₁ and 72a ₂₂ communicate with each other and the opening on the bypass path 78B ₂ side is closed, and the first division path 72a. ₂₁ , the second dividing path 72 a _22, and the bypass path 78 </ _b > B ₂ can communicate with each other (that is, the three states are open).

Here, by the switching operation of each of the flow path switching valves 78A ₁ and 78A ₂ described above, the downstream exhaust gas bypasses the respective bypass passages 78B ₁ and 78B ₂ without passing through the first catalyst devices 73 _LH and 73 _RH. The exhaust gas may be guided to the path, but since the upstream side of the second catalytic device 74 _LH and 74 _RH is set as a detour destination, the exhaust gas is passed through the second catalytic device 74 _LH and 74 _RH . Purified.

In the eighth embodiment, the switching operation of the respective flow path switching valves 78A ₁ and 78A ₂ is controlled by an electronic control unit (ECU) 79 shown in FIG. Each of the flow path switching valves 78A ₁ and 78A ₂ can be switched in any form, such as a valve that moves a valve element with a drive motor, or a valve element that moves hydraulically or pneumatically. Good.

The electronic control unit 79 determines whether or not the internal EGR amount between the cylinders may be different (hereinafter referred to as “internal EGR amount different region”), and determines whether or not each flow path switching valve 78A ₁ , switch the state of 78A _2.

  Here, the internal EGR amount difference region is the blowdown gas generating cylinders # 4, # 5, # 7, # 8 during the valve overlap period of the blowdown gas inflow cylinders # 6, # 3, # 1, # 2. The exhaust valve is open, and can be set in advance by map data corresponding to crank angle information obtained from a crank angle sensor (not shown).

  By the way, the influence of the blowdown gas described above is more likely to be received as the valve opening time at the same time of the respective exhaust valves between the cylinders is longer, and is less likely to be received if the time is shorter. That is, if it is operating at low / medium speed rotation, it will be susceptible to blowdown gas, but if it is operating at high speed rotation, it will be less susceptible to that effect.

For this reason, the electronic control unit 79 according to the eighth embodiment appropriately sets the low / medium speed rotation region shown in FIG. 11 (here, it is set to 3000 rpm or less, but depending on the specifications of the internal combustion engine 71, etc., 4000 rpm or less). ), The flow path switching valves 78A ₁ and 78A ₂ are opened, and the flow path switching valves 78A ₁ and 78A ₂ are kept closed in the high-speed rotation region.

  The operation will be described below with reference to the flowchart of FIG. Here, it is assumed that the first cylinder # 1 is in the valve overlap period as shown in FIG.

  The electronic control unit 79 determines whether or not the internal EGR amount difference region while comparing the crank angle information with the map data (step ST1).

Here, as shown in FIG. 3-2, when the crank angle reaches 360 ° CA, the exhaust valve of the seventh cylinder # 7 in the same bank as the first cylinder # 1 opens to enter the internal EGR amount difference region. For this reason, when the crank angle reaches 360 ° CA, the electronic control unit 79 determines in step ST1 that the internal EGR amount is different, and the flow path switching valves 78A ₁ , 78A are determined based on the information on the engine speed at that time. _It is determined whether or not the valve opening region is ₂ (step ST2).

Then, the electronic control unit 79, the opening area of the flow path switching valve 78A _1, 78A ₂ (i.e., low and medium-speed rotation area) if the flow path switching valve 78A ₁ the second state of the left bank opening the flow path of the bypass passage 78B ₁ is switched to (step ST3).

Thus, blowdown gas of the seventh cylinder # 7, while flowing into the first catalyst device 73 _LH side of the downstream, also flows into the bypass passage 78B _1, merges in the first exhaust pipe 75 _LH. For this reason, the pressure wave of the blowdown gas is attenuated, so that the exhaust interference between the first cylinder # 1 and the seventh cylinder # 7 is reduced, and the internal EGR amount between the cylinders is made uniform and suctioned. The air charging efficiency (air-fuel ratio) becomes constant.

  The electronic control unit 79 may determine that the internal EGR amount difference area immediately before the crank angle reaches 360 ° CA.

  Subsequently, the electronic control unit 79 returns to step ST1 and determines whether or not it is an internal EGR amount difference area while comparing the crank angle information with the map data. In this case, the electronic control unit 79 repeats the process from step ST1 → step ST2 → step ST3 → step ST1.

Here, when the first cylinder # 1 finishes the valve overlap period (the exhaust valve of the first cylinder # 1 is closed), the first cylinder # 1 moves out of the internal EGR amount difference region. Therefore, the electronic control unit 79 determines that it is not the internal EGR amount difference region in step ST1 when the cylinder # 1 reaches the crank angle at which the valve overlap period ends, and the left bank flow path switching valve 78A _1. Close the flow path of the bypass passage 78B ₁ is switched to the first state (step ST4). Similarly, when it is determined in step ST2 that the flow path switching valves 78A ₁ , 78A ₂ are not in the open region (that is, the high speed rotation region), the left bank flow path switching valve 78A _{1 is also connected} to the first bank. Close the flow path of the bypass passage 78B ₁ is switched to a state, or to maintain the first state.

As a result, the blowdown gas of the seventh cylinder # 7 continues to flow to the downstream side of the first catalytic device 73 _LH , but also flows to the remaining cylinders # 1, # 3, # 5 side in the same bank. However, since the exhaust valves of the remaining cylinders # 1, # 3, and # 5 are closed, exhaust interference due to the blowdown gas does not occur.

Incidentally, the electronic control unit 79, the first cylinder # 1 is may maintain a flow path switching valve 78A ₁ even after a crank angle end the valve overlap period to the second state, the purification of exhaust gas Considering the performance, when the valve overlap period is over, all the exhaust gas discharged from the seventh cylinder # 7 passes through the first and second catalytic devices 73 _LH and 74 _LH . It is preferable to switch to the state.

  Thereafter, the electronic control unit 79 returns to step ST1 to determine whether or not the region is the internal EGR amount difference region while comparing the crank angle information with the map data, and repeats the same operation.

As described above, according to the blowdown gas pressure wave attenuating means 78 _LH and 78 _RH of the eighth embodiment, the blowdown gas is attenuated, and the arrival time of the positive pressure wave of the blowdown gas to the other cylinder can be delayed. it can. Therefore, the exhaust pulsation difference between the cylinders # 1 to # 8 can be reduced, and the exhaust interference between the cylinders during the valve overlap period can be suppressed. For this reason, the internal EGR amount between the cylinders, and hence the intake air charging efficiency (air-fuel ratio) can be made uniform.

  And since the charging efficiency (air-fuel ratio) of the intake air between the cylinders can be made uniform as described above, the shaft torque can be improved. Further, since the uniform state of the internal EGR amount between the cylinders and the uniform state of the charging efficiency (air-fuel ratio) of the intake air can be maintained even if the valve overlap period is expanded, the valve overlap period As a result, the amount of internal EGR can be increased, and the amount of HC and NOx emissions can be reduced and the fuel consumption rate can be reduced.

Here, the blowdown gas pressure wave attenuating means 8 as in the first embodiment, the communication pipe 28 as in the third embodiment, the exhaust collecting chambers 42a ₁ and 42a _{2 as in the} fifth embodiment, or a combination of at least two or more thereof are implemented in this embodiment. The present invention may be applied to the internal combustion engine 71 of Example 8, which can more effectively reduce the exhaust interference between the cylinders, and the internal EGR amount between the cylinders, and hence the charging efficiency of the intake air (empty air). (Fuel ratio) can be made uniform effectively.

  Next, an internal combustion engine according to a ninth embodiment of the present invention will be described with reference to FIGS. Here, reference numeral 81 in FIG. 13 indicates the internal combustion engine of the ninth embodiment.

The internal combustion engine 81 of the ninth embodiment includes a cylinder block 81a in which eight cylinders # 1 to # 8 are arranged in the left and right banks and two cylinder heads in the same positional relationship as the internal combustion engine 11 of the second embodiment. This is a V-type eight-cylinder internal combustion engine having 81b _LH and 81b _{RH, in} which each cylinder # 1 to # 8 is ignited in the same ignition order.

Even in the ninth embodiment, on the left bank side, the exhaust ports 81b _{# 1} , 81b _{# 3} , 81b _{# 5} , 81b _{# 7} of each cylinder # 1, # 3, # 5, _{# 7} , exhaust manifold 82 _LH , First and second catalyst devices 83 _LH , 84 _LH and first and second exhaust pipes 85 _LH , 86 _LH are provided, and each cylinder # 2, # 4, # 6 is provided on the right bank side. # 8 exhaust ports 81b _{# 2} , 81b _{# 4} , 81b _{# 6} , 81b _{# 8} , exhaust manifold _82RH , first and second catalytic devices _83RH , _84RH and first and second exhaust pipes _85RH 86 _RH , and the second exhaust pipes 86 _LH and 86 _RH are grouped in one path by the third exhaust pipe 87. These do not necessarily have to be combined into one path by the third exhaust pipe 87. Further, the first exhaust pipes 85 _LH and 85 _RH are gathered in one path, and one catalyst device is arranged in place of the two second catalyst devices 84 _LH and 84 _RH on the downstream side of the gathered portion. May be.

As the exhaust manifolds 82 _LH and 82 _RH of the ninth embodiment, the same 4-2-1 type as in the second embodiment is used. That is, in the left-bank, in the first and fourth exhaust passage 82 _# 1, 82 _# 3, 82 _# 5, 82 manifolds 82a ₁ of the _{# 7} and the first from the 3, 82b _1, 82c ₁ An exhaust manifold 82 _LH is configured, and a first catalyst device 83 _LH is provided at the downstream end of the third collecting passage 82 c ₁ . On the other hand, in the right-bank, in the first and fourth exhaust passage ₈₂ # 2, 82 _# 4, 82 _# 6, 82 _{# 8} from the first third manifolds 82a _2, 82b _2, 82c _{2 RH} exhaust manifold 82 is configured, _RH first catalyzer 83 is provided in the third downstream end manifolds 82c _2.

Here, even in the ninth embodiment, the blow wave shown in FIG. 13 is used to attenuate the pressure wave of the blow-down gas in the fourth cylinder # 4, fifth cylinder # 5, seventh cylinder # 7 and eighth cylinder # 8. Down gas pressure wave attenuating means 88 _LH and 88 _RH are provided in each of the left and right banks.

The blowdown gas pressure wave attenuating means 88 _LH and 88 _RH of the ninth embodiment is the same as the blowdown gas pressure wave attenuating means 78 _LH and 78 _{RH of the} eighth embodiment described above. Of the seventh cylinder # 7, fifth cylinder # 5, fourth cylinder # 4 or eighth cylinder # 8 which generates blowdown gas during the valve overlap period of the # 3, sixth cylinder # 6 or the second cylinder # 2. This is a blowdown gas exhaust path extension structure that extends the flow path and attenuates the pressure wave of the blowdown gas.

That is, the blowdown gas pressure wave attenuating means 88 _LH , 88 _RH of the ninth embodiment is provided with respective exhaust paths through which blowdown gas from the blowdown gas generating cylinders # 4, # 5, # 7, # 8 flows. The amount of internal EGR is increased by the influence of the respective blowdown gas, and the blowdown gas is connected to each exhaust passage through which exhaust gas from the blowdown gas inflow cylinders # 6, # 3, # 1, and # 2 flows. Are provided with bypass passages for bypassing to the downstream exhaust path.

Specifically, the left bank blow-down gas pressure wave attenuating means 88 _{LH in the} ninth embodiment includes the first and second exhaust passages 82 _{# 1} , 82 through the first collecting passage 82 a ₁ of the exhaust manifold 82 _LH . _# in the first and downstream of the merging portion between the ₃ third collecting passage 82a _1, 82b _1, upstream of the confluence portion of the 82c ₁ of the first divided path 82a ₁₁ and the second divided path 82a ₁₂ Divide into Then, while communicating the two openings of the flow path switching valve 88A ₁ with three openings in the respective first and second divided path 82a _11, 82a _12, and the remainder of the opening and the first exhaust pipe 85 _LH It communicates with the bypass passage 88B ₁ and configure.

On the other hand, the blow-down gas pressure wave damping means 88 _RH in the right bank, the first collecting passage 82a ₂ of the _RH exhaust manifold 82, the joining portion between the first and third exhaust passage 82 # _2, 82 # ₆ Are divided into a first dividing path 82a ₂₁ and a second dividing path 82a ₂₂ on the downstream side and upstream of the joining portion of the first to third collecting passages 82a ₂ , 82b ₂ , 82c ₂ , and second divided path 82a _21, 82a ₂₂ and three while allowing the two openings of the flow path switching valve 88A ₂ respectively communicated with an opening, the bypass passage 88B ₂ and the remainder of the opening and the first exhaust pipe 85 _RH And communicate with each other.

Here, as the flow path switching valve 88A ₁ in the left bank of the ninth embodiment, the first and second divided paths 82a ₁₁ and 82a ₁₂ communicate with each other, and the opening on the bypass path 88B ₁ side is closed. and 1 state, and the first divided path 82a ₁₁ and the second divided path 82a ₁₂ and the bypass passage 88B ₁ are communicated (i.e., three openings are open) performed previously described may switch a second state example The same as 8 is used. Similarly, for the right-bank flow path switching valve 88A ₂ , the first state in which the first and second dividing paths 82a ₂₁ and 82a ₂₂ communicate with each other and the opening on the bypass path 88B ₂ side is closed; The first dividing path 82a ₂₁ , the second dividing path 82a _22, and the bypass path 88B ₂ that communicate with each other (that is, the three openings are open) can be used.

Exhaust gas diverted from the bypass passage 88B _1, 88B ₂ each in this embodiment 9, flows into the upstream side of the second catalytic converter 84 _LH, 84 _RH, by the second catalytic converter 84 _LH, 84 _RH Purified.

Further, even in the ninth embodiment, the switching operation of each of the flow path switching valves 88A ₁ and 88A ₂ is the same as in the eighth embodiment, “whether or not it is an internal EGR amount difference area” and “flow path”. It is controlled by an electronic control unit (ECU) 89 shown in FIG. 13 which is a control means based on the determination criterion “whether or not the switching valves 88A ₁ and 88A ₂ are in the open region”. Here, the internal EGR amount difference area is set in advance in map data corresponding to the crank angle information from the crank angle sensor (not shown) even in the ninth embodiment.

  The operation will be described below with reference to the flowchart of FIG. Here, as shown in FIG. 3-2, it is assumed that the first cylinder # 1 is in the valve overlap period.

As in the case of the eighth embodiment, the electronic control unit 89 compares the crank angle information with the map data to determine whether or not it is an internal EGR amount difference area (step ST1). Here, when the crank angle reaches 360 ° CA, the electronic control unit 89 determines that the internal EGR amount is different, and based on the information on the engine speed at that time, the flow control valves 88A ₁ and 88A ₂ It is determined whether or not the valve is open (step ST2).

Then, the electronic control unit 89, the opening area of the flow path switching valve 88A _1, 88A ₂ (i.e., low and medium-speed rotation area) if the flow path switching valve 88A ₁ the second state of the left bank opening the flow path of the bypass passage 88B ₁ is switched to (step ST3).

Thus, blowdown gas of the seventh cylinder # 7, while flowing into the first catalyst device 83 _LH side of the downstream, also flows into the bypass passage 88B _1, merges in the first exhaust pipe 85 _LH. For this reason, the pressure wave of the blowdown gas is attenuated, so that the exhaust pulsation difference between the first cylinder # 1 and the seventh cylinder # 7 is reduced and the exhaust interference is reduced, and the internal EGR between the cylinders is reduced. The amount is made uniform and the charging efficiency (air-fuel ratio) of intake air becomes constant.

Incidentally, the electronic control unit 89 performs the determination of step ST2 to immediately before the crank angle 360 ° CA, to the flow path switching valves 88A ₁ may be performed a switching operation to a second state of the .

Subsequently, the electronic control unit 89 returns to step ST1 and determines whether or not the internal EGR amount difference region is compared with the crank angle information and the map data. Again, the electronic control unit 89, the first cylinder # 1 is determined not to be an internal EGR quantity difference area upon a crank angle end the valve overlap period, the flow path switching valve 88A ₁ of the left bank Close the flow path of the bypass passage 88B ₁ is switched to the first state (step ST4). Even when it is determined in step ST2 that the flow path switching valves 88A ₁ and 88A ₂ are not in the open area (ie, the high speed rotation area), the left bank flow path switching valve 88A ₁ is similarly connected to the first bank. Close the flow path of the bypass passage 88B ₁ is switched to a state, or to maintain the first state.

Thereby, while the blowdown gas of the seventh cylinder # 7 continues to flow to the downstream first catalyst device 83 _LH side, it also flows to the remaining cylinders # 1, # 3, # 5 side in the same bank. Since the exhaust valves of the remaining cylinders # 1, # 3, and # 5 are closed, exhaust interference due to the blowdown gas does not occur.

Incidentally, the electronic control unit 89, the first cylinder # 1 is may maintain a flow path switching valve 88A ₁ even after a crank angle end the valve overlap period to the second state, the purification of exhaust gas Considering the performance, when the valve overlap period is over, all the exhaust gas discharged from the seventh cylinder # 7 passes through the first and second catalytic devices 83 _LH and 84 _LH . It is preferable to switch to the state.

  Thereafter, the electronic control unit 89 returns to the above-described step ST1, determines whether or not the region is the internal EGR amount difference region while comparing the crank angle information and the map data, and repeats the same operation.

As described above, the blowdown gas pressure wave attenuating means 88 _LH and 88 _{RH of the} ninth embodiment also attenuates the blowdown gas in the same manner as in the eighth embodiment, and the positive pressure wave of the blowdown gas reaches the other cylinder. You can delay the time. Therefore, the exhaust pulsation difference between the cylinders # 1 to # 8 can be reduced, and the internal EGR amount is affected by the blowdown gas generating cylinders # 4, # 5, # 7, # 8 and their respective blowdown gases. This makes it possible to reduce the exhaust interference between the blowdown gas inflow cylinders # 6, # 3, # 1, and # 2, so that the amount of internal EGR between the cylinders and the intake air can be reduced. It is possible to make the charging efficiency (air-fuel ratio) uniform.

  And since the charging efficiency (air-fuel ratio) of the intake air between the cylinders can be made uniform as described above, the shaft torque can be improved. Further, since the uniform state of the internal EGR amount between the cylinders and the uniform state of the charging efficiency (air-fuel ratio) of the intake air can be maintained even if the valve overlap period is expanded, the valve overlap period As a result, the amount of internal EGR can be increased, and the amount of HC and NOx emissions can be reduced and the fuel consumption rate can be reduced.

By the way, in the ninth embodiment, the first state where the first and second division paths 82a ₁₁ and 82a ₁₂ communicate with each other and the opening on the bypass passage 88B ₁ side is closed, and the first division path 82a. ₁₁ illustrates the left bank flow path switching valve 88A ₁ capable of switching to the second state in which the second divided path 82a ₁₂ and the bypass path 88B ₁ communicate with each other, while the first and second divided paths 82a ₂₁ and 82a ₂₂ communicate with each other, and the first state in which the opening on the bypass passage 88B ₂ side is closed, the first division path 82a ₂₁ , the second division path 82a ₂₂ and the bypass passage 88B ₂ communicate with each other. has been illustrated a flow path switching valve 88A ₂ in the right bank capable of performing switching between the second state, not limited to those necessarily such aspects.

For example, the flow path switching valve 88A ₁ of the left bank, the first and second divided path 82a _11, 82a ₁₂ are communicated, a first state in which the opening of the bypass passage 88B ₁ side is closed, the second As a flow switching valve 88A ₂ for the right bank, there is prepared a switch that can switch between the second state in which the dividing path 82a ₁₂ communicates with the bypass path 88B ₁ and the opening on the first dividing path 82a ₁₁ side is closed. The first state where the first and second dividing paths 82a ₂₁ and 82a ₂₂ communicate with each other and the opening on the bypass passage 88B ₂ side is closed, and the second dividing path 82a ₂₂ and the bypass passage 88B ₂ communicate with each other. Then, a device capable of switching between the second state in which the opening on the first dividing path 82a ₂₁ side is closed is prepared.

According to each of the flow path switching valves 88A ₁ , 88A ₂ , the blow-down gas generating cylinder is in the internal EGR amount difference region (the valve overlap period of the blow-down gas inflow cylinders # 6, # 3, # 1, # 2). When it is determined that the exhaust valves # 4, # 5, # 7, and # 8 are open), _{one of the} flow path switching valves 88A ₁ and 88A ₂ is set to the second state. By switching, the blowdown gas of the blowdown gas generating cylinders # 4, # 5, # 7, and # 8 flows into the downstream first catalyst devices 83 _LH and 83 _RH, while the bypass passages 88B ₁ , It also flows into 88B ₂ and merges at the first exhaust pipes 85 _LH and 85 _RH .

  For this reason, the pressure wave of the blowdown gas in the blowdown gas generating cylinders # 4, # 5, # 7, # 8 is attenuated, and the blowdown gas inflow cylinders # 6, # 3 of the respective blowdown gases are further attenuated. , # 1 and # 2 are prevented from flowing in, so that exhaust interference between the cylinders corresponding to each of them is suppressed, the internal EGR amount between the cylinders is made uniform, and the intake air charging efficiency (air-fuel ratio) ) Becomes constant.

Here, at that time, the exhaust gas in the exhaust passages related to the blowdown gas inflow cylinders # 6, # 3, # 1, and # 2 does not flow downstream from the respective flow path switching valves 88A ₁ and 88A ₂ . However, since the exhaust gas in the exhaust passage flows into the combustion chambers of the blowdown gas inflow cylinders # 6, # 3, # 1, and # 2 in such a state, the blowdown gas generation cylinders # 4, # 5, There is almost no influence on the equalization of the internal EGR amount between # 7 and # 8.

  Here, the blowdown gas pressure wave attenuating means 18 as in the second embodiment and / or the communication pipe 38 as in the fourth embodiment may be applied to the internal combustion engine 81 of the ninth embodiment. Further, it is possible to reduce the exhaust interference between the cylinders, and to effectively equalize the internal EGR amount between the cylinders, and hence the intake air charging efficiency (air-fuel ratio).

  Next, an internal combustion engine according to a tenth embodiment of the present invention will be described with reference to FIG. Here, reference numeral 91 in FIG. 14 indicates the internal combustion engine of the tenth embodiment.

The internal combustion engine 91 of the tenth embodiment has a cylinder block 91a in which eight cylinders # 1 to # 8 are arranged in the left and right banks and two cylinder heads in the same positional relationship as the internal combustion engine 11 of the second embodiment. This is a V-type 8-cylinder internal combustion engine that includes 91b _LH and 91b _RH , and in which each of the cylinders # 1 to # 8 is ignited in the same ignition sequence.

Even in the tenth embodiment, on the left bank side, exhaust ports 91b _{# 1} , 91b _{# 3} , 91b _{# 5} , 91b _{# 7} of each cylinder # 1, # 3, # 5, _{# 7} , exhaust manifold 92 _LH , First and second catalyst devices 93 _LH , 94 _LH and first and second exhaust pipes 95 _LH , 96 _LH are provided, and each cylinder # 2, # 4, # 6 is provided on the right bank side. # 8 exhaust ports 91b _{# 2} , 91b _{# 4} , 91b _{# 6} , 91b _{# 8} , exhaust manifold _92RH , first and second catalytic devices _93RH , _94RH and first and second exhaust pipes _95RH , 96 _RH are provided, and the second exhaust pipes 96 _LH , 96 _RH are grouped in one path by the third exhaust pipe 97. These do not necessarily have to be combined into one path by the third exhaust pipe 97. Further, the first exhaust pipes 95 _LH and 95 _RH are gathered in one path, and one catalyst device is arranged on the downstream side of the gathered portion instead of the two second catalyst devices 94 _LH and 94 _RH. May be.

As the exhaust manifolds 92 _LH and 92 _RH of the tenth embodiment, the same 4-2-1 type as in the second embodiment is used. That is, in the left-bank, in the first and fourth exhaust passage 92 _# 1, 92 _# 3, 92 _# 5, 92 manifolds 92a ₁ of the _{# 7} and the first from the 3, 92b _1, 92c ₁ An exhaust manifold 92 _LH is configured, and a first catalyst device 93 _LH is provided at the downstream end of the third collecting passage 92 c ₁ . On the other hand, in the right-bank, in the first and fourth exhaust passage ₉₂ # 2, 92 _# 4, 92 _# 6, 92 _{# 8} from the first third manifolds 92a _2, 92b _2, 92c ₂ configured exhaust manifold 92 _{RH, RH} first catalyzer 93 is provided in the third downstream end manifolds 92c _2.

Here, even in the tenth embodiment, the blowdown gas pressure wave that attenuates the pressure wave of the blowdown gas in the fourth cylinder # 4, fifth cylinder # 5, seventh cylinder # 7, and eighth cylinder # 8. Attenuating means 98 _LH and 98 _RH are provided in each of the left and right banks.

In the tenth embodiment, the pressure wave of the blowdown gas discharged from the blowdown gas generating cylinders # 4, # 5, # 7, # 8 is used as the blowdown gas pressure wave attenuating means _98LH , _98RH. Will be described with reference to a structure that attenuates the pressure with a pressure wave attenuating structure such as a damper mechanism.

Specifically, the blowdown gas pressure wave attenuating means 98 _LH in the left bank is a portion where the exhaust manifold 92 _LH joins the third and fourth exhaust passages 92 _{# 5} and 92 _{# 7} in the second collecting passage 92 b ₁ . It is arrange | positioned rather than the downstream. The blowdown gas pressure wave attenuating means 98 _LH is disposed in a damper chamber 98a ₁ communicating with the second collecting passage 92b ₁ and reciprocally moved in the damper chamber 98a ₁ . A piston member 98b ₁ that is pushed by blow-down gas of the numbering cylinder # 7 and an elastic member (here, a string-wound spring) 98c ₁ that pushes back the pushed piston member 98b ₁ are provided.

Thus, fifth part or all of the cylinders # 5 or 7 cylinder # 7 blowdown gas discharged by the opening of the exhaust valve of pushes the piston member 98b _1, blow in the second collecting passage 92b ₁ Attenuates the pressure wave of down gas. The attenuated blowdown gas flows to the first catalyst device 93 _LH side through the third collecting passage 92c ₁ , while the first cylinder # 1 and the third cylinder pass through the first collecting passage 92a _1. It flows to the cylinder # 3 side.

Here, for example, when the exhaust valve of the seventh cylinder # 7 is opened, the first cylinder # 1 is in the overlap period as shown in FIG. 3-2. However, as described above, the second collecting passage 92b ₁ Since the pressure wave of the blowdown gas in the No. 7 cylinder # 7 flowing into the engine is attenuated, the exhaust pulsation difference between the cylinders is reduced, the exhaust interference is reduced, and the internal EGR amount between the cylinders is made uniform. Thus, the charging efficiency (air-fuel ratio) of the intake air becomes constant.

Further, the blow-down gas pressure wave attenuating means 98 _RH in the right bank is more than the portion where the second and fourth exhaust passages 92 _{# 4} and 92 _{# 8} are joined in the second collecting passage 92b ₂ of the exhaust manifold 92 _RH . Arranged downstream. For even _RH The blowdown gas pressure wave damping means 98, similarly to the blowdown gas pressure wave damping means 98 _LH of the left bank, a damper chamber 98a ₂ communicating with the second collecting passage 92b _2, the damper chamber 98a ₂ The piston member 98b ₂ is disposed so as to be reciprocally movable therein and is pushed by blowdown gas of the fourth cylinder # 4 and the eighth cylinder # 8, and the elastic member 98c that pushes back the pushed piston member 98b ₂ . _{And two} .

This order, fourth part or all of the blowdown gas discharged by opening the exhaust valve of cylinder # 4, or 8 cylinder # 8 pushes the piston member 98b _2, blow in the second collecting passage 92b ₂ Attenuates the pressure wave of down gas. The blowdown gas was allowed to its attenuation, the third one that flows into the first catalyst device 93 _RH side through the collecting passage 92c _2, 6 cylinder # 6 and # 2 via a first collecting passage 92a ₂ It flows to the cylinder # 2 side.

Thus, according to the blowdown gas pressure wave attenuating means 98 _LH and 98 _RH of the tenth embodiment, the blow of the fourth cylinder # 4, fifth cylinder # 5, seventh cylinder # 7 or eighth cylinder # 8 is blown. It is possible to attenuate the down gas and delay the arrival time of the blow-down gas positive pressure wave at the other cylinder. Therefore, the exhaust pulsation difference between the cylinders can be reduced, and the exhaust interference can be reduced. Therefore, the internal EGR amount between the respective cylinders, and hence the intake air charging efficiency (air-fuel ratio) can be reduced. Uniformity can be achieved.

  And since the charging efficiency (air-fuel ratio) of the intake air between the cylinders can be made uniform as described above, the shaft torque can be improved. Further, since the uniform state of the internal EGR amount between the cylinders and the uniform state of the charging efficiency (air-fuel ratio) of the intake air can be maintained even if the valve overlap period is expanded, the valve overlap period As a result, the amount of internal EGR can be increased, and the amount of HC and NOx emissions can be reduced and the fuel consumption rate can be reduced.

Here, the blow-down gas pressure wave attenuating means 18 as in the second embodiment, the communication pipe 38 as in the fourth embodiment, the blow-down gas pressure wave attenuating means 88 _LH and 88 _{RH as in the} ninth embodiment, or at least two or more thereof. The combination may be applied to the internal combustion engine 91 of the tenth embodiment, and this makes it possible to more effectively reduce the exhaust interference between the cylinders, and to reduce the internal EGR amount between the cylinders and the intake air. Filling efficiency (air-fuel ratio) can be effectively made uniform.

  Next, an internal combustion engine according to an eleventh embodiment of the present invention will be described with reference to FIG. Here, reference numeral 101 in FIG. 15 indicates the internal combustion engine of the eleventh embodiment.

The internal combustion engine 101 of the eleventh embodiment has a cylinder block 101a in which eight cylinders # 1 to # 8 are arranged in the left and right banks and two cylinder heads in the same positional relationship as the internal combustion engine 1 of the first embodiment. This is a V-type 8-cylinder internal combustion engine that includes 101b _LH and 101b _RH , and in which each cylinder # 1 to # 8 is ignited in the same firing order.

Even in the eleventh embodiment, on the left bank side, the exhaust ports 101b _{# 1} , 101b _{# 3} , 101b _{# 5} , 101b _{# 7} of each cylinder # 1, # 3, # 5, _{# 7} , exhaust manifold 102 _LH , First and second catalyst devices 103 _LH , 104 _LH and first and second exhaust pipes 105 _LH , 106 _LH are provided, and each cylinder # 2, # 4, # 6 is provided on the right bank side. # 8 exhaust ports 101b _{# 2} , 101b _{# 4} , 101b _{# 6} , 101b _{# 8} , exhaust manifold _102RH , first and second catalytic devices _103RH , _104RH , and first and second exhaust pipes _105RH , 106 _RH are provided, and the second exhaust pipes 106 _LH , 106 _RH are grouped in one path by the third exhaust pipe 107. Note that these are not necessarily combined into one path by the third exhaust pipe 107. Further, the first exhaust pipes 105 _LH and 105 _RH are gathered in one path, and one catalyst device is arranged in place of the two second catalyst devices 104 _LH and 104 _RH on the downstream side of the gathered portion. May be.

As the exhaust manifolds 102 _LH and 102 _RH of the eleventh embodiment, the same 4-1 type as in the first embodiment is used. That is, on the left bank side, the first to fourth exhaust passages 102 _{# 1} , 102 _{# 3} , 102 _{# 5} , 102 _{# 7} and the collecting passage 102 a ₁ constitute an exhaust manifold 102 _LH , and the right bank side an exhaust manifold 102 _RH at a set passage 102a ₂ and the fourth exhaust passage 102 _# 2, 102 _# 4, 102 _# 6, 102 _{# 8} from the first is constituted in.

Here, even in the eleventh embodiment, in order to avoid the influence of the blowdown gas between the cylinders whose exhaust valves are open at the same time, the blowdown gas that attenuates the pressure wave of the blowdown gas is used. Pressure wave attenuating means 108 _LH and 108 _RH are provided in the left and right banks, respectively.

In the eleventh embodiment, the pressure wave of the blowdown gas discharged from the blowdown gas generating cylinders # 4, # 5, # 7, # 8 is used as the blowdown gas pressure wave attenuating means _108LH , _108RH. Is damped with a pressure wave attenuating structure such as a pressure wave absorbing member.

Specifically, the blowdown gas pressure wave attenuating means 108 _LH and 108 _RH of the eleventh embodiment are pressure wave absorbing members provided on the entire inner wall surfaces of the exhaust manifolds 102 _LH and 102 _RH , respectively. It consists of a structure and a material which can attenuate the pressure wave of the exhaust gas discharged | emitted from 1- # 8.

  The pressure wave absorbing member performs experiments, simulations, etc., and the blowdown gas from each of the blowdown gas generation cylinders # 4, # 5, # 7, and # 8 generated periodically as shown in FIG. The pressure wave can be effectively attenuated. For example, the blowdown gas inflow increases due to the respective blowdown gas generation cylinders # 4, # 5, # 7, and # 8 and their respective blowdown gases. A structure or material is provided so that the pressure waves of the exhaust gases between the cylinders # 6, # 3, # 1, and # 2 are substantially equal. For example, the pressure wave absorbing member may be a member provided with an uneven structure such as a wall surface of an anechoic chamber on the surface in contact with the exhaust gas.

  As a result, the pressure wave absorbing member absorbs the pressure waves of the blowdown gas in the blowdown gas generating cylinders # 4, # 5, # 7, and # 8, and the blowdown gas inflow cylinders # 6, # 3, # The propagation of the pressure wave of the blowdown gas to 1, # 2 is suppressed, or a damped pressure wave reaches each of the cylinders # 6, # 3, # 1, # 2. For this reason, the exhaust pulsation difference between the cylinders is reduced and the exhaust interference is reduced, so that the internal EGR amount between the cylinders is made uniform, and the intake air charging efficiency (air-fuel ratio) becomes constant.

As described above, according to the blowdown gas pressure wave attenuating means 108 _LH and 108 _{RH as} in the eleventh embodiment, the blowdown gas is attenuated and the arrival time of the positive pressure wave of the blowdown gas to the other cylinder is delayed. Can do. For this reason, the exhaust pulsation difference between the cylinders on the same bank in each bank can be reduced, and the exhaust interference between the cylinders can be reduced, so that the internal EGR amount between the cylinders, and hence the suction, can be reduced. Air filling efficiency (air-fuel ratio) can be made uniform.

  And since the charging efficiency (air-fuel ratio) of the intake air between the cylinders can be made uniform as described above, the shaft torque can be improved. Further, since the uniform state of the internal EGR amount between the cylinders and the uniform state of the charging efficiency (air-fuel ratio) of the intake air can be maintained even if the valve overlap period is expanded, the valve overlap period As a result, the amount of internal EGR can be increased, and the amount of HC and NOx emissions can be reduced and the fuel consumption rate can be reduced.

In the eleventh embodiment, blowdown gas pressure wave attenuating means 108 _LH and 108 _RH (pressure wave absorbing members) are provided on the entire inner wall surfaces of the exhaust manifolds 102 _LH and 102 _RH. Gas pressure wave attenuating means 108 _LH , 108 _RH (pressure wave absorbing members) are the first cylinder, the second cylinder, the third cylinder and the sixth cylinder in which the blowdown gas when the exhaust valve is opened does not affect the other cylinders. The # 6 exhaust passages 102 _{# 1} , 102 _{# 2} , 102 _{# 3} , and 102 _{# 6} are not necessarily arranged.

Here, the blowdown gas pressure wave attenuating means 8 as in the first embodiment, the communication pipe 28 as in the third embodiment, the exhaust collecting chambers 42a ₁ and 42a _{2 as in the} fifth embodiment, or the blowdown gas pressure wave as in the eighth embodiment. The damping means 78 _LH , 78 _RH or a combination of at least two thereof may be applied to the internal combustion engine 101 of the eleventh embodiment, thereby more effectively reducing the exhaust interference between the respective cylinders. The amount of internal EGR between the cylinders, and hence the intake air charging efficiency (air-fuel ratio) can be effectively equalized.

  Next, an internal combustion engine according to a twelfth embodiment of the present invention will be described with reference to FIG. Here, reference numeral 111 in FIG. 16 indicates the internal combustion engine of the twelfth embodiment.

The internal combustion engine 111 of the twelfth embodiment has a cylinder block 111a in which eight cylinders # 1 to # 8 are arranged in left and right banks and two cylinder heads in the same positional relationship as the internal combustion engine 11 of the second embodiment. This is a V-type 8-cylinder internal combustion engine that includes 111b _LH and 111b _RH , and in which each cylinder # 1 to # 8 is ignited in the same firing order.

Even in the twelfth embodiment, the left bank side has exhaust ports 111b _{# 1} , 111b _{# 3} , 111b _{# 5} , 111b _{# 7} , exhaust manifold 112 _LH of each cylinder # 1, # 3, # 5, # 7. , First and second catalyst devices 113 _LH , 114 _LH and first and second exhaust pipes 115 _LH , 116 _LH are provided, and each cylinder # 2, # 4, # 6 is provided on the right bank side. # 8 exhaust ports 111b _{# 2} , 111b _{# 4} , 111b _{# 6} , 111b _{# 8} , exhaust manifold _112RH , first and second catalytic devices _113RH , _114RH , and first and second exhaust pipes _115RH , 116 _RH are provided, and the respective second exhaust pipes 116 _LH , 116 _RH are combined into one path by the third exhaust pipe 117. These do not necessarily have to be combined into one path by the third exhaust pipe 117. Further, the first exhaust pipes 115 _LH and 115 _RH are gathered in one path, and one catalyst device is arranged in place of the two second catalyst devices 114 _LH and 114 _RH on the downstream side of the gathered portion. May be.

As the exhaust manifolds 112 _LH and 112 _RH of the twelfth embodiment, the same 4-2-1 type as in the second embodiment is used. That is, on the left bank side, the first to fourth exhaust passages 112 _{# 1} , 112 _{# 3} , 112 _{# 5} , 112 _{# 7} and the first to third collective passages 112 a ₁ , 112 b ₁ , 112 c ₁ An exhaust manifold 112 _LH is configured, and a first catalyst device 113 _LH is provided at the downstream end of the third collecting passage 112 c ₁ . On the other hand, on the right bank side, the first to fourth exhaust passages 112 _{# 2} , 112 _{# 4} , 112 _{# 6} , 112 _{# 8} and the first to third collective passages 112 a ₂ , 112 b ₂ , 112 c ₂ An exhaust manifold 112 _RH is configured, and a first catalyst device 113 _RH is provided at the downstream end of the third collecting passage 112 c ₂ .

Here, even in the twelfth embodiment, in order to avoid the influence of the blowdown gas between the cylinders whose exhaust valves are open at the same time, the blowdown gas that attenuates the pressure wave of the blowdown gas is used. Pressure wave attenuating means 118 _LH and 118 _RH are provided in the left and right banks, respectively. As the blowdown gas pressure wave attenuating means 118 _LH and 118 _RH of the twelfth embodiment, the same pressure wave attenuating structure (pressure wave absorbing member) as that of the eleventh embodiment is used.

The pressure wave absorbing member may be provided on the entire inner wall surface of each of the exhaust manifolds 112 _LH and 112 _RH as in the eleventh embodiment. However, in the twelfth embodiment, as shown in FIG. It is provided on the inner wall surface of only the exhaust path related to the down gas generating cylinders # 4, # 5, # 7, and # 8.

Specifically, in the exhaust manifold 112 _LH of the left bank, the inner wall surfaces of the third and fourth exhaust passages 112 _{# 5} and 112 _{# 7} and the second set associated with the fifth cylinder # 5 and the seventh cylinder # 7 A pressure wave absorbing member is provided on the inner wall surface of the passage 112b ₁ , thereby configuring the blow-down gas pressure wave attenuating means 118 _LH on the left bank side.

On the other hand, in the exhaust manifold 112 _RH in the right bank, the inner wall surfaces of the second and fourth exhaust passages 112 _{# 4} and 112 _{# 8} related to the fourth cylinder # 4 and the eighth cylinder # 8, and the second collecting passage 112b _A pressure wave absorbing member is provided on the inner wall surface of ₂ , thereby constituting blow-down gas pressure wave attenuating means 118 _RH on the right bank side.

  For this reason, the exhaust pulsation difference between the cylinders on the same bank can be reduced and the exhaust interference between the cylinders can be reduced as in the eleventh embodiment, so that the internal EGR amount and the extension between the cylinders can be reduced. Therefore, the charging efficiency (air-fuel ratio) of intake air can be made uniform.

  And since the charging efficiency (air-fuel ratio) of the intake air between the cylinders can be made uniform as described above, the shaft torque can be improved. Further, since the uniform state of the internal EGR amount between the cylinders and the uniform state of the charging efficiency (air-fuel ratio) of the intake air can be maintained even if the valve overlap period is expanded, the valve overlap period As a result, the amount of internal EGR can be increased, and the amount of HC and NOx emissions can be reduced and the fuel consumption rate can be reduced.

Here, such a blow-mentioned blowdown gas pressure wave damping means 18 or Example 4 of such such as communicating pipe 38 or Example 9 blowdown gas pressure wave damping means 88 _LH, 88 _RH or Example 10 Example 2 The down gas pressure wave attenuating means 98 _LH , 98 _RH or a combination of at least two of them may be applied to the internal combustion engine 111 of the twelfth embodiment, thereby more effectively preventing the exhaust interference between the cylinders. Reduction can be achieved, and the internal EGR amount between the cylinders, and thus the intake air charging efficiency (air-fuel ratio) can be made uniform.

  Next, an internal combustion engine according to a thirteenth embodiment of the present invention will be described with reference to FIGS. Here, reference numeral 121 in FIG. 17 indicates the internal combustion engine of the thirteenth embodiment.

The internal combustion engine 121 of the thirteenth embodiment has a cylinder block 121a in which eight cylinders # 1 to # 8 are arranged in the left and right banks in the same positional relationship as the internal combustion engine 1 of the first embodiment and two cylinder heads. This is a V-type 8-cylinder internal combustion engine that includes 121b _LH and 121b _RH , and in which each cylinder # 1 to # 8 is ignited in the same firing order.

Even in the thirteenth embodiment, the exhaust ports 121b _{# 1} , 121b _{# 3} , 121b _{# 5} , 121b _{# 7} , exhaust manifold 122 _{LH of the} cylinders # 1, # 3, # 5, and # 7 are provided on the left bank side. , First and second catalyst devices 123 _LH , 124 _LH and first and second exhaust pipes 125 _LH , 126 _LH are provided, and each cylinder # 2, # 4, # 6 is provided on the right bank side. # 8 exhaust ports 121b _{# 2} , 121b _{# 4} , 121b _{# 6} , 121b _{# 8} , exhaust manifold _122RH , first and second catalytic devices _123RH , _124RH , and first and second exhaust pipes _125RH , 126 _RH are provided, and the second exhaust pipes 126 _LH , 126 _RH are grouped in one path by the third exhaust pipe 127. Note that these do not necessarily have to be combined into one path by the third exhaust pipe 127. Further, the first exhaust pipes 125 _LH and 125 _RH are gathered in one path, and one catalyst device is arranged in place of the two second catalyst devices 124 _LH and 124 _RH on the downstream side of the gathered portion. May be.

As the exhaust manifolds 122 _LH and 122 _RH of the thirteenth embodiment, the same 4-1 type as in the first embodiment is used. That is, in the left bank side is formed an exhaust manifold 122 _LH in the first to the fourth exhaust passage 122 _# 1, 122 _# 3, 122 _# 5, 122 _{# 7} with manifolds 122a _1, also right-bank an exhaust manifold 122 _RH at a set passage 122a ₂ and the fourth exhaust passage 122 _# 2, 122 _# 4, 122 _# 6, 122 _{# 8} from the first is constituted in.

By the way, for example, when the engine temperature is about 20 ° C. (especially when the engine is cold), the intake air temperature is generally lower and the fuel vaporization characteristics deteriorate when the engine is cold (particularly when the engine is cold). The fuel injection amount is increased to make the air-fuel ratio deeper than the stoichiometric air-fuel ratio. For this reason, for example, at the time of engine cold start, the conversion efficiency of HC and CO in the first catalyst devices 123 _LH and 123 _RH decreases, and the HC and CO in the exhaust gas after passing through the first catalyst devices 123 _LH and 123 _RH CO concentration becomes high.

Therefore, in the internal combustion engine 121 of the thirteenth embodiment, the secondary air supply devices 128 _LH and 128 _RH shown in FIG. 17 are provided on the left and right banks in order to reduce HC and CO in the exhaust gas when the engine is cold started. Is provided.

First, the secondary air supply device 128 _LH on the left bank side is in communication with the first to fourth exhaust passages 122 _{# 1} , 122 _{# 3} , 122 _{# 5} , 122 _{# 7} in the exhaust manifold 122 _LH . The first to fourth secondary air supply pipes 128 _{# 1} , 128 _{# 3} , 128 _{# 5} , 128 _{# 7} and the first to fourth secondary air supply pipes 128 _{# 1} , 128 _{# 3} , 128 _{# 5} , 128 _{# 7} the communicating pipe 128a ₁ for communicating, are constituted by a pump 128b ₁ for pumping secondary air to the communicating pipe 128a _1.

On the other hand, the secondary air supply apparatus 128 _RH of the right bank side, the communicating from the first in the exhaust manifold 122 _RH to the fourth exhaust passage 122 _# 2, 122 _# 4, 122 _# 6, 122 _{# 8} and the individual The first to fourth secondary air supply pipes 128 _{# 2} , 128 _{# 4} , 128 _{# 6} , 128 _{# 8} , and these first to fourth secondary air supply pipes 128 _{# 2} , 128 _{# 4} , 128 _{# 6} , 128 _{# 8} and a communication pipe 128a ₂ that communicates with the communication pipe 128a ₂ and a pump 128b ₂ that pumps secondary air to the communication pipe 128a ₂ .

In each of these secondary air supply devices 128 _LH and 128 _RH , the supply of secondary air is performed by an electronic control device (ECU) 129 shown in FIG. For example, when the oil temperature or the water temperature is about 20 ° C. or less, the pumps 128b ₁ and 128b ₂ are driven by the electronic control unit 129, and the exhaust passages 122 _{# 1 to} 122 _{# 8} are set to 2 Supply secondary air.

The pumps 128b ₁ and 128b ₂ of the thirteenth embodiment are assumed to be stopped unless a drive command is given from the electronic control unit 129. Further, two such pumps 128b _1, instead 128b _2, may be configured only the secondary air supply apparatus 128 _LH, 128 _RH in one pump.

Here, when supplying the secondary air, the electronic control unit 129 increases the fuel injection amount so as to be deeper than the stoichiometric air-fuel ratio, so the unburned fuel in the exhaust gas increases. For this reason, the temperature of the exhaust gas rises due to the unburned fuel and the secondary air in the exhaust gas, and the first catalytic devices 123 _LH and 123 _RH are activated early. HC and CO can be reduced.

On the other hand, when the secondary air is not supplied, secondary air supply passages such as the secondary air supply pipes 128 _{# 1 to} 128 _{# 7} of the respective secondary air supply devices 128 _LH and 128 _RH and the communication pipes 128 a ₁ and 128 a _2. In some cases, exhaust gas flows into each of the exhaust passages 122 _{# 1 to} 122 _{# 8} .

In such a case, the flow path of the exhaust gas is extended by the secondary air supply passage (secondary air supply pipes 128 _{# 1 to} 128 _{# 7} and communication pipes 128a ₁ , 128a _2, etc.). The pressure wave of the gas is attenuated. Therefore, in such a case, the secondary air supply devices 128 _LH and 128 _RH also function as blowdown gas pressure wave attenuation means.

Here, even in a situation where there is no difference in the internal EGR amount between the cylinders, if the exhaust gas flows into the communication pipes 128a ₁ and 128a ₂ , the temperature decreases due to the exhaust gas passage extension. The activation of the one catalyst device 123 _LH or 123 _RH may be impaired, which is not preferable from the viewpoint of exhaust gas purification performance.

Therefore, in the thirteenth embodiment, secondary air supply passages (secondary air supply pipes 128 _{# 1 to} 128 _{# 7} and communication pipes 128a ₁ and 128a ₂ etc.) and exhaust passages 122 _{# 1 to} 122 _{# 8 are provided.} DOO communication or interruptible flow channel opening and closing valve 128c _# 1 ~128c _{# 8} respectively provided to the flow channel opening and closing valve 128c _# 1 ~128c _{# 8} in a predetermined operating condition where the difference in the internal EGR amount occurs among the cylinders open The exhaust gas flow path is extended by the valve.

For example, the respective flow channel opening and closing valve 128c _# 1 ～128C _{# 8,} as shown in FIG. 17, on each secondary air supply apparatus 128 _LH, 128 _RH of the secondary air supply pipe 128 _# 1 to 128 _{# 8} In addition, an electromagnetic valve capable of opening and closing the flow paths of the secondary air supply pipes 128 _{# 1 to} 128 _{# 8} with an electronic control unit 129 is provided.

In order to reduce the number of parts, a butterfly valve such as a throttle valve is arranged in each of the secondary air supply pipes 128 _{# 1 to} 128 _{# 8} , and the butterfly valve is connected to the drive motor drive shaft for each bank. The flow path opening / closing valves 128c _{# 1 to} 128c _{# 8} may be configured by connecting them with each other. Similarly, in order to reduce the number of parts, a slide valve that can reciprocate in a direction perpendicular to the axial direction of each of the secondary air supply pipes 128 _{# 1 to} 128 _{# 8} , and a drive that moves the slide valve Each flow path opening / closing valve 128c _{# 1 to} 128c _{# 8} may be configured by a driving device such as a motor or a gear.

Here, when each of the secondary air supply devices 128 _LH and 128 _{RH is made} to function as a blow-down gas pressure wave attenuating means, as in the above-described eighth and ninth embodiments, “whether or not the region is an internal EGR amount difference region”. "Is used as a judgment criterion, and the electronic control device 129 controls the operation of the respective flow path opening / closing valves 128c _{# 1 to} 128c _{# 8} .

In this case, the electronic control device 129 is shown in FIG. 11 because the pressure wave does not have to be attenuated during high-speed rotation operation that is hardly affected by the blowdown gas for the same reason as in the eighth and ninth embodiments. The flow path opening / closing valves 128c _{# 1 to} 128c _{# 8} are opened only in the low / medium speed rotation region. In the thirteenth embodiment, the “flow path switching valve opening area” in FIG. 11 is read as “flow path opening / closing valve opening area”.

  The operation will be described below with reference to the flowchart of FIG.

  First, the electronic control unit 129 determines whether or not the engine is cold (for example, the oil temperature or the water temperature is about 20 ° C. or less) based on the detection signal of the oil temperature sensor or the water temperature sensor (step ST11).

Here, if the engine cold, the electronic control unit 129, is opened all the flow channel opening and closing valve 128c _# 1 ~128c _{# 8} (step ST12), thereafter, pump each 128b _1, 128b ₂ Is driven (pump ON) (step ST13).

As a result, secondary air is supplied into the exhaust gas in the rich region flowing through the respective exhaust passages 122 _{# 1 to} 122 _{# 8,} and early activation of the downstream first catalyst devices 123 _LH and 123 _RH due to the temperature rise of the exhaust gas. As a result, HC and CO in the exhaust gas when the engine is cold are reduced.

For example, the secondary air in such a case continues to be supplied for about 20 seconds, and then the electronic control unit 129 stops (pumps OFF) the respective pumps 128b ₁ and 128b ₂ and all the flow path opening / closing valves 128c _{# 1.} -128c _{# 8} is closed.

  On the other hand, if it is determined in step ST11 that the engine is not cold, the electronic control unit 129 determines whether or not the internal EGR amount difference region while comparing the crank angle information with the map data. (Step ST14).

  For example, as shown in FIG. 3-2, the first cylinder # 1 is in the valve overlap period, and when the crank angle reaches 360 ° CA, the exhaust of the seventh cylinder # 7 in the same bank as the first cylinder # 1 is performed. The valve opens to enter the internal EGR amount difference area. For this reason, the electronic control unit 129 determines that the internal EGR amount difference area when the crank angle reaches 360 ° CA, and determines whether or not it is the flow path on-off valve opening area based on the information on the engine speed at that time. Judgment is made (step ST15).

In the electronic control unit 129, if the flow path opening / closing valve opening region (that is, the low / medium speed rotation region), the flow path opening / closing valve of the bank having the respective cylinders serving as the internal EGR amount difference region ( Here, the flow path opening / closing valves 128c _{# 1} , 128c _{# 3} , 128c _{# 5} , 128c _{# 7} ) in the left bank are opened (step ST16).

As a result, the blowdown gas of the seventh cylinder # 7 flows from the fourth exhaust passage 122 _{# 7} into the communication pipe 128a ₁ through the secondary air supply pipe 128 _{# 7} . For this reason, the pressure wave of the blowdown gas is attenuated, and the attenuated blowdown gas reaches the other cylinders # 1, # 3, and # 5 in the same bank. Exhaust interference with the numbering cylinder # 7 is reduced, the internal EGR amount between the cylinders is made uniform, and the intake air charging efficiency (air-fuel ratio) becomes constant.

  The electronic control unit 129 may determine that the internal EGR amount difference area immediately before the crank angle reaches 360 ° CA.

  Subsequently, the electronic control unit 129 returns to step ST11 and repeats the same processing operation. In this case, the electronic control unit 129 repeats the processing in steps ST11 → STEP14 → STEP15 → STEP ST16 → STEP ST11.

Here, when the first cylinder # 1 finishes the valve overlap period (the exhaust valve of the first cylinder # 1 is closed), the first cylinder # 1 moves out of the internal EGR amount difference region. For this reason, the electronic control unit 129 determines that the internal EGR amount is not different in step ST14 when the first cylinder # 1 reaches the crank angle at which the valve overlap period ends, and all the flow path opening / closing valves 128c _{# 1} -128c _{# 8} is closed. (Step ST17). Similarly, when it is determined in step ST15 that the flow path opening / closing valves 128c _{# 1 to} 128c _{# 8} are not in the open region (that is, the high speed rotation region), all the flow path opening / closing valves 128c _{# 1 to} 128c Close _{# 8} .

As a result, the blowdown gas of the seventh cylinder # 7 continues to flow to the downstream side of the first catalyst device 123 _LH , but also flows to the remaining cylinders # 1, # 3, # 5 side in the same bank. Since the exhaust valves of the remaining cylinders # 1, # 3, and # 5 are closed, exhaust interference due to the blowdown gas does not occur.

  Thereafter, the electronic control unit 129 returns to step ST11 and repeats the same processing operation.

As described above, by causing the secondary air supply devices 128 _LH and 128 _RH to function as blowdown gas pressure wave attenuation means as in the thirteenth embodiment, the blowdown gas is attenuated, and the normality of the blowdown gas is increased. The arrival time of the pressure wave to the other cylinder can be delayed. Therefore, the exhaust pulsation difference between the cylinders # 1, # 3, # 5, and # 7 in the left bank and the exhaust pulsation difference between the cylinders # 2, # 4, # 6, and # 8 in the right bank are reduced. Blowdown gas generating cylinders # 4, # 5, # 7, and # 8 and blowdown gas inflow cylinders # 6, # 3, # 1, and # 8 whose internal EGR amount increases due to their respective blowdown gases Therefore, it is possible to reduce the internal EGR amount between the respective cylinders, and hence the intake air charging efficiency (air-fuel ratio).

  And since the charging efficiency (air-fuel ratio) of the intake air between the cylinders can be made uniform as described above, the shaft torque can be improved. Further, since the uniform state of the internal EGR amount between the cylinders and the uniform state of the charging efficiency (air-fuel ratio) of the intake air can be maintained even if the valve overlap period is expanded, the valve overlap period As a result, the amount of internal EGR can be increased, and the amount of HC and NOx emissions can be reduced and the fuel consumption rate can be reduced.

As described above, in the thirteenth embodiment, it is important to surely open and close the respective flow path opening / closing valves 128c _{# 1 to} 128c _{# 8} , while the flow path opening / closing valves 128c _{# 1 to} 128c _{#. When} an abnormality occurs in ₈ , the opening / closing operation is preferably suppressed.

Therefore, it is desirable to provide a channel on / off valve failure detection means capable of detecting a failure of each of the channel on / off valves 128c _{# 1 to} 128c _{# 8} as follows.

For example, as shown in FIG. 19, a pressure sensor 128d, a check valve 128e and a relief valve 128f are provided in each of the communication pipes 128a ₁ and 128a ₂ , respectively, and the electronic control device 129 has a failure of the flow path opening / closing valves 128c _{# 1 to} 128c _{# 8} . Provide a detection function. In FIG. 19, only the left bank side is shown for convenience.

Here, the pressure sensor 128 d detects the pressure in the communication pipes 128 a ₁ and 128 a ₂ , and the detection signal is sent to the electronic control unit 129. Further, the check valve 128e are pumps respectively 128b _1, from 128b ₂ air while to flow into the communicating pipe 128a _1, 128a in _2, the communicating pipe 128a _1, 128a in ₂ air and exhaust gases respective This prevents the pumps 128b ₁ and 128b ₂ from flowing out. The relief valve 128f releases the pressure when the pressure in the communication pipes 128a ₁ and 128a ₂ reaches a predetermined pressure.

In this type of flow path on / off valve failure detection means, as shown in the flowchart of FIG. 20, first, the electronic control unit 129 closes all the flow path on / off valves 128c _{# 1 to} 128c _{# 8} (step ST21). Thereafter, the respective pumps 128b ₁ and 128b ₂ are driven (pump ON) (step ST22).

Then, while monitoring the detection signal of the pressure sensor 128d, the electronic control unit 129 stops the pumps 128b ₁ and 128b ₂ (pump OFF) when the detection value Ps reaches the predetermined value P1 (step ST23). ). The relief valve 128f is set so as not to be released by the pressure of the predetermined value P1.

  The electronic control unit 129 holds such a state for a certain time (x seconds), and determines whether or not the detected value Ps from the pressure sensor 128d after x seconds is greater than a predetermined threshold value P2 (<P1) (step). ST24) If it is larger, it is determined that there is no abnormality, and the process is terminated.

On the other hand, if the detected value Ps is less than or equal to the predetermined threshold value P2, it is determined that there is an abnormality, and the electronic control unit 129 turns on, for example, a warning light in the passenger compartment (step ST25), and the flow path opening / closing valve 128c _# 1˜ The open / close control prohibition flag of 128c _{# 8} is turned ON (step ST26).

  Here, such a failure diagnosis is executed periodically during traveling (for example, every certain traveling distance, every certain traveling time, every predetermined time, etc.).

In addition, as the flow path opening / closing valves 128c _{# 1 to} 128c _{# 8} , for example, an angle detection unit that uses a valve that opens and closes a flow path by changing the angle, such as a butterfly valve such as a throttle valve, can detect the angle. If it is provided, the failure detection of the flow path opening / closing valves 128c _{# 1 to} 128c _{# 8} can be performed as follows.

In such a case, the electronic control unit 129 always monitors the opening angle of the flow path opening and closing valve 128c _# 1 ~128c _{# 8,} the following every time to perform the opening and closing control of the flow channel opening and closing valve 128c _# 1 ~128c _{# 8} Fault diagnosis shall be performed.

First, as shown in the flowchart of FIG. 21, the electronic control unit 129 performs the difference between the required opening / closing angle θreq and the actual valve body angle θreal when executing the opening / closing control of the flow path opening / closing valves 128c _{# 1 to} 128c _{# 8.} Is smaller than a predetermined value α (step ST31). The predetermined value α is preferably as small as possible, but is preferably set to a value of, for example, 1 degree or less in consideration of tolerances of the valve body and the like.

Here, if the difference is smaller than the predetermined value α, it is determined that there is no abnormality and the process is terminated. On the other hand, if the difference is larger than the predetermined value α, it is determined that there is an abnormality, and the electronic control unit 129 turns on, for example, a warning lamp in the passenger compartment (step ST32), and the flow path opening / closing valves 128c _{# 1 to} 128c _#. The open / close control prohibition flag ₈ is turned ON (step ST33).

According to such a channel on / off valve failure detection means, it becomes possible to individually diagnose each of the channel on / off valves 128c _{# 1 to} 128c _{# 8} .

Also, when as a flow path opening and closing valve 128c _# 1 ~128c _{# 8} an electromagnetic valve as shown in Figure 22-1 and Figure 22-2 for example, the flow passage opening and closing valve in the following manner 128c _# 1 ~128c _{# 8} failure detection can be performed. Here, the flow path opening / closing valves 128c _{# 1 to} 128c _{# 8} are exemplified as the flow path opening / closing valve 128c _{# 7} . FIG. 22-1 shows the state when the valve is opened, and FIG. 22-2 shows the state when the valve is closed.

As Figure 22-1 and flow channel opening and closing valve 128c _{# 7} shown in FIG. 22-2, a valve body 128c ₁ of the flow channel is formed in which is provided rotatably in the housing 128c _2. The valve body 128c ₁ is provided with a valve body side electrode 128c ₃ that rotates integrally. The housing 128c ₂ includes an open electrode 128c ₄ that is close to the valve element side electrode 128c ₃ when the valve is opened, and a closed electrode 128c ₅ that is close to the valve element side electrode 128c ₃ when the valve is closed.

  In the case of this type of flow path opening / closing valve 128c, the following failure diagnosis is performed each time the opening / closing control is executed.

  First, as shown in the flowchart of FIG. 23, the electronic control unit 129 determines how the channel on / off valve 128c is controlled to open / close (open or closed) (step ST41).

Here, when the valve opening control is executed, the electronic control unit 129 applies a voltage to the open side electrode 128c ₄ (step ST42), and a current between the open side electrode 128c ₄ and the valve body side electrode 128c _3. A value is detected (step ST43).

  Then, if it is a predetermined current value, it is determined that there is no abnormality, and the process is terminated. If the predetermined current value is not reached or no current is detected, there is an abnormality (the valve is not opened correctly). For example, the electronic control unit 129 turns on a warning lamp in the vehicle interior (step ST44), and turns on the open control prohibition flag of the flow path opening / closing valve 128c (step ST45).

On the other hand, when executing the closing control, the electronic control unit 129, by applying a voltage to the closed side electrode 128c ₅ (step ST46), the current value between the closing side electrode 128c ₅ and the valve body side electrode 128c ₃ Is detected (step ST47).

  Then, if it is a predetermined current value, it is determined that there is no abnormality, and the process is terminated. If the current value has not been reached or no current is detected, there is an abnormality (the valve is not closed correctly). For example, the electronic control unit 129 turns on a warning light in the vehicle interior (step ST48), and turns on the close control prohibition flag of the flow path opening / closing valve 128c (step ST49).

Such flow path opening / closing valve failure detection means can also diagnose each of the flow path opening / closing valves 128c _{# 1 to} 128c _{# 8} individually.

Here, the blowdown gas pressure wave attenuating means 8 as in the first embodiment, the communication pipe 28 as in the third embodiment, the exhaust collecting chambers 42a ₁ and 42a _{2 as in the} fifth embodiment, or the blowdown gas pressure wave as in the eighth embodiment. The damping means 78 _LH , 78 _RH or the blowdown gas pressure wave damping means 108 _LH , 108 _{RH as in the} eleventh embodiment or a combination of at least two of them may be applied to the internal combustion engine 121 of the thirteenth embodiment. As a result, exhaust interference between the cylinders can be more effectively reduced, and the internal EGR amount between the cylinders, and hence the intake air charging efficiency (air-fuel ratio) can be effectively equalized.

  Next, an internal combustion engine according to a fourteenth embodiment of the present invention will be described with reference to FIGS.

  The internal combustion engine of the fourteenth embodiment has the same configuration as the internal combustion engine 121 of the thirteenth embodiment shown in FIG. 17, and the control method of the electronic control unit 129 is changed from that of the thirteenth embodiment.

Here, in Example 13 I described above, respectively of the secondary air supply device 128 _LH, 128 _RH in the secondary air supply passage (secondary air supply pipe 128 _# 1 to 128 _{# 8} and communicating tube 128a _1, 128a ₂ ) Function as a blowdown gas pressure wave attenuating means.

However, such a configuration is not preferable because a large amount of exhaust gas may stay in the secondary air supply pipes 128 _{# 1 to} 128 _{# 8} and the communication pipes 128 a ₁ and 128 a ₂ .

On the other hand, the secondary air supply devices 128 _LH and 128 _RH increase the temperature of the exhaust gas if the secondary air is supplied when operating at the air-fuel ratio in the rich region. When the secondary air is supplied while operating at the air-fuel ratio, the temperature of the exhaust gas decreases.

  Here, in a fluid such as exhaust gas, a proportional relationship is established between the sound speed c and the temperature T as shown in the following formula 1, and the sound speed c decreases as the temperature T decreases. Have. Here, κ represents the specific heat ratio of the exhaust gas, and R represents the gas constant of the exhaust gas.

Thus, by supplying secondary air into the exhaust gas flowing through the exhaust passages 122 _{# 1 to} 122 _{# 8} , the temperature of the exhaust gas can be lowered and the pressure wave of the blowdown gas can be attenuated.

Therefore, in the fourteenth embodiment, the secondary air supply devices 128 _LH and 128 _RH are blown down by supplying the secondary air in a predetermined operation state in which the difference in internal EGR amount between the cylinders occurs. It functions as a pressure wave attenuating means.

Here, in the fourteenth embodiment, when the secondary air supply devices 128 _LH and 128 _RH function as blowdown gas pressure wave attenuating means, as in the eighth and ninth embodiments described above, The electronic control unit 129 is made to control the operation of the secondary air supply devices 128 _LH and 128 _RH and the flow path opening / closing valves 128 c _{# 1 to} 128 c _{# 8 based on} the determination criterion “whether or not the EGR amount is different”.

  In this case, the electronic control device 129 is shown in FIG. 11 because the pressure wave does not have to be attenuated during high-speed rotation operation that is hardly affected by the blowdown gas for the same reason as in the eighth and ninth embodiments. Secondary air is supplied only in the low / medium speed rotation region. In the fourteenth embodiment, the “flow path switching valve opening region” in FIG. 11 is read as “secondary air supply region”.

  The operation will be described below with reference to the flowchart of FIG.

First, as in the thirteenth embodiment, the electronic control unit 129 determines whether or not the engine is cold (step ST51), and if the engine is cold, all the flow path opening / closing valves 128c _{# 1 to} 128c _{#. 8} is opened (step ST52), and then the respective pumps 128b ₁ and 128b ₂ are driven (pumps ON) (step ST53), and the secondary air is supplied to the respective exhaust passages 122 _{# 1 to} 122 _{# 8.} Supply.

  On the other hand, if it is determined in step ST51 that the engine is not cold, the electronic control unit 129 determines whether or not the internal EGR amount difference region is the same as in the thirteenth embodiment (step ST54). If it is determined that the internal EGR amount difference region is determined, it is determined whether or not the region is the secondary air supply region based on the information on the engine speed at that time (step ST55).

The electronic control unit 129 is a bank having blowdown gas generating cylinders # 4, # 5, # 7, and # 8 at that time in the secondary air supply region (that is, the low / medium speed rotation region). The flow path on / off valves 128c _{# 1} , 128c _{# 3} , 128c _{# 5} , 128c _{# 7} (or 128c _{# 2} , 128c _{# 4} , 128c _{# 6} , 128c _{# 8} ) are opened (step ST56). The bank-side pump 128b ₁ (or 128b ₂ ) is driven (pump ON) (step ST57).

As a result, the secondary air is supplied to the exhaust passages 122 _{# 1} , 122 _{# 3} , 122 _{# 5} , 122 _{# 7} (or 122 _{# 2} , 122 _{# 4} , 122 _{# 6} , 122 _{# 8} ) of the bank, The blow-down gas generated in the bank is attenuated in pressure pressure as the temperature decreases, and the blow-down gas attenuated reaches the other cylinders in the same bank. For this reason, the exhaust pulsation difference between the cylinders (for example, between the first cylinder # 1 and the seventh cylinder # 7) is reduced and the exhaust interference is reduced, so that the internal EGR amount between the cylinders is made uniform. As a result, the charging efficiency (air-fuel ratio) of the intake air becomes constant.

Here, when the electronic control unit 129 determines that it is not the internal EGR amount difference region in step ST54 or when it is determined that it is not the secondary air supply region (that is, the high-speed rotation region) in step ST55, to close the flow passage opening and closing valve 128c _# 1 ~128c _{# 8} (step ST58), thereby discharging and all the exhaust gases to the first catalyst device 123 _LH, 123 _RH side.

  Thereafter, the electronic control unit 129 returns to step ST51 and repeats the same processing operation.

As shown above, the secondary air supply devices 128 _LH and 128 _RH actively function as blowdown gas pressure wave attenuating means as in the fourteenth embodiment, so that the blowdown gas is attenuated more effectively. The arrival time of the blowdown gas in the positive pressure wave at the other cylinder can be delayed. Therefore, the exhaust pulsation difference between the cylinders # 1, # 3, # 5, and # 7 in the left bank and the exhaust pulsation difference between the cylinders # 2, # 4, # 6, and # 8 in the right bank are reduced. Blowdown gas generating cylinders # 4, # 5, # 7, and # 8 and blowdown gas inflow cylinders # 6, # 3, # 1, and # 8 whose internal EGR amount increases due to their respective blowdown gases Therefore, it is possible to reduce the internal EGR amount between the respective cylinders, and hence the intake air charging efficiency (air-fuel ratio).

  And since the charging efficiency (air-fuel ratio) of the intake air between the cylinders can be made uniform as described above, the shaft torque can be improved. Further, since the uniform state of the internal EGR amount between the cylinders and the uniform state of the charging efficiency (air-fuel ratio) of the intake air can be maintained even if the valve overlap period is expanded, the valve overlap period As a result, the amount of internal EGR can be increased, and the amount of HC and NOx emissions can be reduced and the fuel consumption rate can be reduced.

Here, the blowdown gas pressure wave attenuating means 8 as in the first embodiment, the communication pipe 28 as in the third embodiment, the exhaust collecting chambers 42a ₁ and 42a _{2 as in the} fifth embodiment, or the blowdown gas pressure wave as in the eighth embodiment. The damping means 78 _LH , 78 _RH or the blowdown gas pressure wave damping means 108 _LH , 108 _{RH as in the} eleventh embodiment or a combination of at least two of them may be applied to the internal combustion engine 121 of the fourteenth embodiment. As a result, exhaust interference between the cylinders can be more effectively reduced, and the internal EGR amount between the cylinders, and hence the intake air charging efficiency (air-fuel ratio) can be effectively made uniform.

  Next, an internal combustion engine according to a fifteenth embodiment of the present invention will be described with reference to FIGS.

  The internal combustion engine of the fifteenth embodiment has the same configuration as the internal combustion engine 121 of the thirteenth and fourteenth embodiments shown in FIG. 17, and the control method of the electronic control unit 129 is changed with respect to the thirteenth and fourteenth embodiments. Is.

Here, in the fourteenth embodiment described above, the secondary air supply of the bank having the blowdown gas generating cylinders # 4, # 5, # 7, and # 8 is performed in a predetermined operation state in which a difference in internal EGR amount between the cylinders occurs. Secondary air is supplied from the devices 128 _LH and 128 _RH .

However, in the fourteenth embodiment, since the secondary air is supplied also to the cylinders on the same bank where no blowdown gas is generated, the first catalyst devices 123 _LH and 123 _RH are obtained by supercooling the exhaust gas. In addition, the second catalyst devices 124 _LH and 124 _RH may be deactivated.

Thus, in the fifteenth embodiment, the exhaust passages 122 _{# 2} , 122 _{# 3} , 122 _{# 4} , 122 _{# 5} , 122 _{# 7} , # 8 of the blowdown gas generating cylinders # 4, # 5, # 7, # 8, The electronic control unit 129 is configured to supply secondary air only to 122 _{# 8} .

  The operation will be described below with reference to the flowchart of FIG.

  The processing operations in steps ST61 to ST65 and step ST68 in FIG. 25 are the same as the processing operations in steps ST51 to ST55 and step ST58 shown in FIG.

When the electronic control unit 129 of the fifteenth embodiment determines that the secondary air supply region (that is, the low / medium speed rotation region) is obtained in step ST65, the blowdown gas generating cylinders # 4, # 5, and # at that time are determined. 7 and # 8 channel opening / closing valves (one of each channel opening / closing valve 128 _{# 4} , 128 _{# 5} , 128 _{# 7} , and 128 _{# 8} ) are opened (step ST66). The bank-side pump 128b ₁ (or 128b ₂ ) having the cylinder is driven (pump ON) (step ST67).

As a result, the secondary air is supplied to the exhaust passage (any one of the exhaust passages 122 _{# 4} , 122 _{# 5} , 122 _{# 7} , 122 _{# 8} ) communicating with the flow path opening / closing valve. . The blow-down gas discharged into the exhaust passage is attenuated in pressure pressure as the temperature decreases, and the attenuated blow-down gas reaches another cylinder in the same bank. Therefore, exhaust interference between the cylinders (for example, between the first cylinder # 1 and the seventh cylinder # 7) is reduced, the internal EGR amount between the cylinders is made uniform, and the intake air charging efficiency (air-fuel ratio) ) Becomes constant, while overcooling of the exhaust gas can be prevented, and inactivation of the first catalyst devices 123 _LH and 123 _RH and the second catalyst devices 124 _LH and 124 _RH can be avoided.

  Thereafter, the electronic control unit 129 returns to step ST61 and repeats the same processing operation.

As described above, by supplying secondary air only to a specific cylinder as in the fifteenth embodiment, the first catalyst devices 123 _LH and 123 _RH and the second catalyst devices 124 _LH and 124 _RH are not _affected . While avoiding activation, the blowdown gas can be attenuated and the arrival time of the positive pressure wave of the blowdown gas to the other cylinder can be delayed. Therefore, the exhaust gas purification performance is ensured, and further, the exhaust pulsation difference of each cylinder # 1, # 3, # 5, # 7 in the left bank and each cylinder # 2, # 4, # 6, # in the right bank The exhaust pulsation difference of 8 is reduced, and the blowdown gas generating cylinders # 4, # 5, # 7, # 8 and the blowdown gas inflow cylinder # in which the amount of internal EGR increases due to the influence of the respective blowdown gases # Exhaust interference between 6, # 3, # 1, and # 2 can be reduced.

  Further, by reducing the exhaust interference, the internal EGR amount between the cylinders, and thus the intake air charging efficiency (air-fuel ratio) can be made uniform, thereby improving the shaft torque. Further, since the uniform state of the internal EGR amount between the cylinders and the uniform state of the charging efficiency (air-fuel ratio) of the intake air can be maintained even if the valve overlap period is expanded, the valve overlap period As a result, the amount of internal EGR can be increased, and the amount of HC and NOx emissions can be reduced and the fuel consumption rate can be reduced.

Here, the blowdown gas pressure wave attenuating means 8 as in the first embodiment, the communication pipe 28 as in the third embodiment, the exhaust collecting chambers 42a ₁ and 42a _{2 as in the} fifth embodiment, or the blowdown gas pressure wave as in the eighth embodiment. The damping means 78 _LH , 78 _RH or the blowdown gas pressure wave damping means 108 _LH , 108 _{RH as in the} eleventh embodiment or a combination of at least two of them may be applied to the internal combustion engine 121 of the fifteenth embodiment. As a result, exhaust interference between the cylinders can be more effectively reduced, and the internal EGR amount between the cylinders, and hence the intake air charging efficiency (air-fuel ratio) can be effectively equalized.

  Next, a sixteenth embodiment of the internal combustion engine according to the present invention will be described with reference to FIG. Here, reference numeral 131 in FIG. 26 indicates the internal combustion engine of the sixteenth embodiment.

The internal combustion engine 131 of the sixteenth embodiment has a cylinder block 131a in which eight cylinders # 1 to # 8 are arranged in the left and right banks and two cylinder heads in the same positional relationship as the internal combustion engine 11 of the second embodiment. This is a V-type 8-cylinder internal combustion engine having 131b _LH and 131b _RH , and in which each cylinder # 1 to # 8 is ignited in the same ignition sequence.

Even in the sixteenth embodiment, the left bank side has exhaust ports 131b _{# 1} , 131b _{# 3} , 131b _{# 5} , 131b _{# 7} , exhaust manifold 132 _LH of each cylinder # 1, # 3, # 5, # 7. , First and second catalyst devices 133 _LH and 134 _LH and first and second exhaust pipes 135 _LH and 136 _LH are provided, and each cylinder # 2, # 4, # 6 is provided on the right bank side. exhaust port 131b _# 2, 131b _# 4 of _{# 8, 131b # 6, 131b} # 8, an exhaust manifold 132 _RH, the first and second catalytic device 133 _RH, 134 _RH and the first and second exhaust pipes 135 _RH , 136 _RH , and the second exhaust pipes 136 _LH and 136 _RH are grouped in one path by the third exhaust pipe 137. Note that these do not necessarily have to be combined into one path by the third exhaust pipe 137. Further, the first exhaust pipes 135 _LH and 135 _RH are gathered in one path, and one catalyst device is arranged on the downstream side of the gathered portion instead of the two second catalyst devices 134 _LH and 134 _RH. May be.

As the exhaust manifolds 132 _LH and 132 _RH of the sixteenth embodiment, the same 4-2-1 type as in the second embodiment is used. That is, in the left-bank, in the first and fourth exhaust passage 132 _# 1, 132 _# 3, 132 _# 5, 132 manifolds 132a ₁ and _{# 7} and the first to 3, 132b _1, 132c ₁ An exhaust manifold 132 _LH is configured, and a first catalyst device 133 _LH is provided at the downstream end of the third collecting passage 132c ₁ . On the other hand, in the right-bank, in the first and fourth exhaust passage 132 _# 2, 132 _# 4, 132 _# 6, 132 set the _{# 8} and the first of the third passage 132a _2, 132b _2, 132c ₂ An exhaust manifold 132 _RH is configured, and a first catalyst device 133 _RH is provided at the downstream end of the third collecting passage 132 c ₂ .

Here, also in the present embodiment 16, secondary air supply devices 138 _LH and 138 _RH similar to those in the embodiments 13 to 15 described above are provided in the left and right banks, respectively, and the blowdown gas pressure wave is similarly applied. It also functions as a damping means.

That is, on the left bank side, the first to fourth secondary air that guides the secondary air to the first to fourth exhaust passages 132 _{# 1} , 132 _{# 3} , 132 _{# 5} , 132 _{# 7} in the exhaust manifold 132 _LH . The air supply pipes 138 _{# 1} , 138 _{# 3} , 138 _{# 5} , and 138 _{# 7} are communicated with the first to fourth secondary air supply pipes 138 _{# 1} , 138 _{# 3} , 138 _{# 5} , and 138 _{# 7} . a communicating pipe 138a _1, this communicating pipe 138a ₁ secondary air supply device 138 _LH with a pump 138b ₁ that pumps are provided the secondary air, further, the fourth secondary air from the first On the supply pipes 138 _{# 1} , 138 _{# 3} , 138 _{# 5} , and 138 _{# 7} , flow path opening / closing valves 138c _{# 1} , 138c _{# 3} , 138c _{# 5} , and 138c _{# 7} are provided.

On the other hand, on the right bank side, the first to fourth secondary air for guiding the secondary air to the first to fourth exhaust passages 132 _{# 2} , 132 _{# 4} , 132 _{# 6} , 132 _{# 8} in the exhaust manifold _132RH . The air supply pipes 138 _{# 2} , 138 _{# 4} , 138 _{# 6} , and 138 _{# 8} are communicated with the first to fourth secondary air supply pipes 138 _{# 2} , 138 _{# 4} , 138 _{# 6} , and 138 _{# 8} . a communicating pipe 138a _2, this communicating pipe 138a ₂ the secondary air supply apparatus 138 _RH with a pump 138b ₂ which pumps is provided with secondary air, further, the fourth secondary air from the first On the supply pipes 138 _{# 2} , 138 _{# 4} , 138 _{# 6} , and 138 _{# 8} , flow path opening / closing valves 138c _{# 2} , 138 c _{# 4} , 138 c _{# 6} , and 138 c _{# 8} are provided.

Each of the secondary air supply devices 138 _LH and 138 _RH and the flow path opening / closing valves 138c _{# 1 to} 138c _{# 8} are controlled by the electronic control unit (ECU) 139 shown in FIG. It is controlled similarly.

  Therefore, in the internal combustion engine 131 of the sixteenth embodiment as well, in the same way as in the thirteenth to fifteenth embodiments, it is possible to attenuate the blowdown gas and delay the arrival time of the positive pressure wave of the blowdown gas to the other cylinder. Therefore, the exhaust pulsation difference between the cylinders # 1, # 3, # 5, and # 7 in the left bank and the exhaust pulsation difference between the cylinders # 2, # 4, # 6, and # 8 in the right bank are reduced. Since the exhaust interference between the cylinders can be reduced, the internal EGR amount between the cylinders, and thus the intake air charging efficiency (air-fuel ratio) can be made uniform.

  And since the charging efficiency (air-fuel ratio) of the intake air between the cylinders can be made uniform as described above, the shaft torque can be improved. Further, since the uniform state of the internal EGR amount between the cylinders and the uniform state of the charging efficiency (air-fuel ratio) of the intake air can be maintained even if the valve overlap period is expanded, the valve overlap period As a result, the amount of internal EGR can be increased, and the amount of HC and NOx emissions can be reduced and the fuel consumption rate can be reduced.

Here, such a blow-mentioned blowdown gas pressure wave damping means 18 or Example 4 of such such as communicating pipe 38 or Example 9 blowdown gas pressure wave damping means 88 _LH, 88 _RH or Example 10 Example 2 The down gas pressure wave attenuating means 98 _LH , 98 _RH or the blow down gas pressure wave attenuating means 118 _LH , 118 _{RH as in the} twelfth embodiment or a combination of at least two of them are applied to the internal combustion engine 131 of the present embodiment 16. As a result, the exhaust interference between the cylinders can be reduced more effectively, and the internal EGR amount between the cylinders and the intake air charging efficiency (air-fuel ratio) can be effectively equalized. .

  In the first to sixteenth embodiments described above, the first cylinder # 1 → 8th cylinder # 8 → 7th cylinder # 7 → 3rd cylinder # 3 → 6th cylinder # 6 → 5th cylinder # 5 → 4th Although the case where the order of ignition of the cylinder # 4 → second cylinder # 2 is set as an example, the present invention can be applied to other ignition orders.

  For example, the firing order is 1st cylinder # 1 → 8th cylinder # 8 → 4th cylinder # 4 → 3rd cylinder # 3 → 6th cylinder # 6 → 5th cylinder # 5 → 7th cylinder # 7 → 2nd In the case of cylinder # 2, if the valve overlap period is set in this ignition order, the first cylinder # 1, the fifth cylinder # 5, the sixth cylinder # 6, and the eighth cylinder # 8 become blowdown gas generating cylinders. The seventh cylinder # 7, the third cylinder # 3, the fourth cylinder # 4 and the second cylinder # 2 are affected by the blowdown gas.

  Further, the ignition order is 1st cylinder # 1 → 2nd cylinder # 2 → 7th cylinder # 7 → 8th cylinder # 8 → 4th cylinder # 4 → 5th cylinder # 5 → 6th cylinder # 6 → 3rd cylinder In the case of # 3, if the valve overlap period is set in this ignition order, the third cylinder # 3, sixth cylinder # 6, seventh cylinder # 7 and eighth cylinder # 8 become blowdown gas generating cylinders. The fifth cylinder # 5, the fourth cylinder # 4, the first cylinder # 1, and the second cylinder # 2 are affected by the blowdown gas.

  For this reason, the present invention illustrated in each of the first to sixteenth embodiments uses the intake air between the blow-down gas generating cylinder corresponding to the ignition order and the cylinder in which the internal EGR amount increases due to the influence of each blow-down gas. The charging efficiency (air-fuel ratio) is made uniform.

  As described above, the internal combustion engine according to the present invention eliminates the difference in internal EGR amount between a cylinder that generates blowdown gas and a cylinder in which the internal EGR amount increases due to the blowdown gas. This is useful as a technique for equalizing the charging efficiency (air-fuel ratio) of intake air between the two.

1 is a diagram illustrating a configuration of a first embodiment of an internal combustion engine according to the present invention. FIG. FIG. 2 is a cross-sectional view of the internal combustion engine of the first embodiment cut along line XX shown in FIG. 1. FIG. 4 is a diagram showing an example of valve opening / closing timings of an intake valve and an exhaust valve in a V-type 8-cylinder internal combustion engine, and a blow-down gas generation cylinder when a valve overlap period is set and a blow affected by the blow-down gas It is a figure which shows the correspondence with a down gas inflow cylinder. FIG. 3 is a diagram showing an example of valve opening / closing timings of an intake valve and an exhaust valve in a V-type 8-cylinder internal combustion engine, and a blowdown gas generation cylinder when the valve overlap period is expanded by means such as a variable valve timing mechanism and the like It is a figure which shows the correspondence with the blowdown gas inflow cylinder which receives the influence of blowdown gas. It is a figure which shows the structure of Example 2 of the internal combustion engine which concerns on this invention. It is a figure which shows the structure of Example 3 of the internal combustion engine which concerns on this invention. It is a figure which shows the structure of Example 4 of the internal combustion engine which concerns on this invention. It is a figure which shows the structure of Example 5 of the internal combustion engine which concerns on this invention. It is a figure which shows the structure of Example 6 of the internal combustion engine which concerns on this invention. It is a figure which shows the structure of Example 7 of the internal combustion engine which concerns on this invention. It is a figure which shows the structure of Example 8 of the internal combustion engine which concerns on this invention. It is explanatory drawing explaining the flow-path switching valve opening area | region of Example 8. FIG. 16 is a flowchart illustrating a control operation of a flow path switching valve in an eighth embodiment. It is a figure which shows the structure of Example 9 of the internal combustion engine which concerns on this invention. It is a figure which shows the structure of Example 10 of the internal combustion engine which concerns on this invention. It is a figure which shows the structure of Example 11 of the internal combustion engine which concerns on this invention. It is a figure which shows the structure of Example 12 of the internal combustion engine which concerns on this invention. It is a figure which shows the structure of Example 13 of the internal combustion engine which concerns on this invention. It is a flowchart explaining the control operation | movement of the secondary air supply apparatus and flow-path on-off valve in Example 13. It is a figure which shows the structure of the failure detection means of the flow path on-off valve in Example 13. FIG. 20 is a flowchart for explaining a failure diagnosis operation using the flow path opening / closing valve failure detection means shown in FIG. It is a flowchart explaining the failure diagnosis operation | movement using the flow path on-off valve failure detection means of another structure. It is a figure which shows the other structure of a flow-path on-off valve failure detection means, Comprising: It is a figure which shows the state at the time of valve opening of a flow-path on-off valve. It is a figure which shows the state at the time of valve closing of the flow-path on-off valve in the flow-path on-off valve failure detection means shown to FIGS. It is a flowchart explaining the failure diagnosis operation | movement using the flow-path on-off valve failure detection means shown to FIGS. 22-1 and 22-2. It is a flowchart explaining the control operation | movement of the secondary air supply apparatus and flow-path on-off valve in Example 14. It is a flowchart explaining the control operation | movement of the secondary air supply apparatus and flow-path on-off valve in Example 15. It is a figure which shows the structure of Example 16 of the internal combustion engine which concerns on this invention.

Explanation of symbols

1 Internal combustion engine 1b _{# 1 to} 1b _{# 8} Exhaust port 2 _LH , 2 _RH Exhaust manifold 2 _{# 1} to 2 _{# 8} Exhaust passage 8 Blowdown gas pressure wave attenuating means 8 _LH first pressure wave attenuating tube 8 _RH second pressure wave Damping pipe 8b Communication pipe 11 Internal combustion engine 11b _{# 1 to} 11b _{# 8} Exhaust port 12 _LH , 12 _RH Exhaust manifold 12 _{# 1 to} 12 _{# 8} Exhaust passage 18 Blowdown gas pressure wave attenuating means 18 _LH first pressure wave attenuating pipe 18 _RH second pressure wave damping pipe 18b communicating pipe 21 internal combustion engine 22 _LH, 22 _RH exhaust manifold 22a _1, 22a ₂ collecting passage 23 _LH, 23 _RH first catalyzer 24 _LH, 24 _RH second catalytic device 25 _LH, 25 _RH First exhaust pipe 28 Communication pipe (Blowdown gas pressure wave attenuating means)
31 Internal combustion engine 32 _LH , 32 _RH Exhaust manifold 32 c ₁ , 32 c ₂ Third collecting passage 33 _LH , 33 _RH First catalyst device 34 _LH , 34 _RH Second catalyst device 35 _LH , 35 _RH First exhaust pipe 38 Communication pipe ( Blowdown gas pressure wave attenuation means)
41 internal combustion engine 42 _LH, 42 _RH exhaust manifold 42 _# 1-42 _{# 8} exhaust passage 42a _1, 42a ₂ exhaust collecting chamber (blowdown gas pressure wave damping means)
51 Internal combustion engine 52 Exhaust manifold 52 _{# 1 to} 52 _{# 8} Exhaust passage 52a Exhaust collecting chamber (blowdown gas pressure wave attenuating means)
61 Internal combustion engine 62 _LH , 62 _RH Exhaust manifold (blowdown gas pressure wave attenuating means)
62 _{# 1 to} 62 _{# 8} Exhaust passage 62 a ₁ , 62 a ₂ Collective passage 71 Internal combustion engine 72 _LH , 72 _RH Exhaust manifold 72 _{# 1 to} 72 _{# 8} Exhaust passage 72 a ₁ , 72 a ₂ Collective passage 72 a ₁₁ , 72 a ₂₁ First division road 72a _12, 72a ₂₂ second divided path 73 _LH, 73 _RH first catalyzer 74 _LH, 74 _RH second catalytic converter 75 _LH, 75 _RH first exhaust pipe 78 _LH, 78 _RH blowdown gas pressure wave damping means 78A ₁ , 78A ₂ flow path switching valve 78B ₁ , 78B ₂ bypass passage 79 Electronic control unit (ECU)
81 Internal combustion engine 82 _LH , 82 _RH Exhaust manifold 82 _# 1-82 _{# 8} Exhaust passage 82 a ₁ , 82 a ₂ First collecting passage 82 a ₁₁ , 82 a ₂₁ First dividing passage 82 a ₁₂ , 82 a ₂₂ Second dividing passage 83 _LH , 83 _RH first catalyst device 84 _LH , 84 _RH second catalyst device 85 _LH , 85 _RH first exhaust pipe 88 _LH , 88 _RH blowdown gas pressure wave attenuating means 88A ₁ , 88A ₂ flow path switching valve 88B ₁ , 88B ₂ bypass Passage 89 Electronic control unit (ECU)
91 Internal combustion engine 92 _LH , 92 _RH Exhaust manifold 92 _{# 1 to} 92 _{# 8} Exhaust passage 92 _{b 1} , 92 _b 2 Second collecting passage 98 _LH , 98 _RH Blowdown gas pressure wave damping means 98 a ₁ , 98 a ₂ Damper chamber 98 _{b 1} , 98b ₂ piston member 98c ₁ , 98c ₂ elastic member 101 internal combustion engine 102 _LH , 102 _RH exhaust manifold 102 _{# 1 to} 102 _{# 8} exhaust passage 102a ₁ collecting passage 102a ₂ collecting passage _108LH , 108 _RH blowdown gas pressure wave attenuating means 111 Internal combustion engine 112 _LH , 112 _RH Exhaust manifold 112 _{# 1 to} 112 _{# 8} Exhaust passage 112 a ₁ , 112 a ₂ First collecting passage 112 b ₁ , 112 b ₂ Second collecting passage 118 _LH , 118 _RH Blowdown gas pressure wave attenuating means 121 Internal combustion engine 122 _LH , 122 _RH Exhaust manifold 122 _# 1-122 _{# 8} Exhaust passage 128 _LH , 1 28 _RH secondary air supply device (blowdown gas pressure wave attenuation means)
128 _{# 1 to} 128 _{# 8} Secondary air supply pipe 128a ₁ , 128a ₂ communication pipe 128b ₁ , 128b ₂ pump 128c _{# 1 to} 128c _{# 8} flow path opening / closing valve 129 Electronic control unit (ECU)
131 Internal combustion engine 132 _LH , 132 _RH Exhaust manifold 132 _# 1-132 _{# 8} Exhaust passage 138 _LH , 138 _RH Secondary air supply device (blowdown gas pressure wave attenuating means)
138 _{# 1} to 138 _{# 8} Secondary air supply pipes 138a ₁ and 138a ₂ communication pipes 138b ₁ and 138b ₂ pumps 138c _{# 1 to} 138c _{# 8} flow path opening / closing valve 139 Electronic control unit (ECU)
# 1- # 8 1st cylinder-8th cylinder

Claims (4)

In an internal combustion engine that has two banks and each cylinder on the same bank explodes at unequal intervals,
Exhaust path communicating means for communicating each exhaust path of each cylinder arranged in the one bank and each exhaust path of each cylinder arranged in the other bank is discharged from the blowdown gas generating cylinder An internal combustion engine provided as blowdown gas pressure wave attenuating means for attenuating a pressure wave of blowdown gas. For each bank, an exhaust path through which exhaust gas from each cylinder disposed on the same bank flows, and a catalyst device through which exhaust gas flows through the exhaust path, are provided,
2. The internal combustion engine according to claim 1, further comprising a communication pipe that communicates the exhaust path of each bank in front of each of the catalyst devices as the blowdown gas pressure wave attenuating means. The internal combustion engine according to claim 1 or 2, further comprising a blowdown gas exhaust path extending structure in which an exhaust path of the blowdown gas generating cylinder is extended as the blowdown gas pressure wave attenuating means. A first catalyst device into which exhaust gas flows and a second catalyst device into which exhaust gas that has passed through the first catalyst device flows;
As the blowdown gas exhaust path extension structure, the blowdown gas is provided between the exhaust path of the blowdown gas generating cylinder and the exhaust path of the blowdown gas inflow cylinder where the amount of internal EGR increases due to the effect of the blowdown gas. The internal combustion engine according to claim 3, wherein a bypass passage is provided for bypassing the exhaust gas to the downstream side of the first catalyst device.

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