JP2007154766A - Internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To equalize quantity of burned gas supplied to each cylinder when burned gas is transferred via communication paths establishing communication among a plurality of cylinders. <P>SOLUTION: One ends of #1 - #4 communication paths 18A - 18D of which another ends are connected to #1 - #4 cylinders 11A - 11D arranged in series are collected at a collection part 23, and the collection part 23 is connected to an exhaust pipe via a connection pipe opened and closed by an open and close valve 25. The #1 and #4 cylinders 11A, 11D positioned at outer sides in an arrangement direction transfer burned gas via the #1, #4 communication paths 18A, 18D, and the #2 and #3 cylinders 11B, 11C positioned at inner sides in the arrangement direction transfer burned gas via the #2, #3 communication paths 18B, 18C. One ends of the #1, #4 communication paths 18A, 18D cross on the collection part 23 with forming obtuse angles therebetween, one ends of the #2, #3 communication paths 18B, 18C cross on the collection part 23 with forming acute angles therebetween, and a connection pipe 24 is provided on an extended line of one ends of the #2, #3 communication paths 18B, 18C. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an internal combustion engine that supplies burned gas from a cylinder in an expansion stroke or an exhaust stroke among a plurality of cylinders arranged in series to one cylinder in an intake stroke or a compression stroke via a communication path. About.

In the in-line four-cylinder internal combustion engine, the # 1 cylinder and the # 4 cylinder on the outer side in the cylinder arrangement direction are connected to each other through the first EGR passage, and the # 2 cylinder and the # 3 cylinder on the inner side in the cylinder arrangement direction are connected to each other through the second EGR passage. The EGR gas is exchanged between the # 1 cylinder and the # 4 cylinder via the first EGR passage, and the EGR gas is exchanged between the # 2 cylinder and the # 3 cylinder via the second EGR passage. This is known from Patent Document 1 below.
JP 2005-61324 A

  However, in the above-described conventional one, the first EGR passage that communicates the outer # 1 cylinder and the # 4 cylinder in the cylinder arrangement direction is longer, and the second EGR passage that communicates the inner # 2 cylinder and the # 3 cylinder in the cylinder arrangement direction. Since it becomes shorter, the time for the burned gas to pass through the first EGR passage becomes longer and the time for the burned gas to pass through the second EGR passage becomes shorter, and the amount of EGR gas supplied to each cylinder becomes uneven due to the time difference. There was a possibility.

  The present invention has been made in view of the above-described circumstances, and in the case where burned gas is transferred through a communication path communicating between a plurality of cylinders, the amount of burned gas supplied to each cylinder is made uniform. The purpose is to do.

  In order to achieve the above object, according to the first aspect of the present invention, there is provided a plurality of communication passages having different lengths for communicating a plurality of cylinders arranged in series with each other. In an internal combustion engine that supplies burned gas from one cylinder in the expansion stroke or exhaust stroke to one cylinder in the intake stroke or compression stroke through the communication path, the two cylinders that exchange the burned gas are An internal combustion engine is proposed in which the shape of the communication passage to be communicated is set so that the time during which burned gas passes therethrough is substantially equal.

  According to the second aspect of the present invention, the # 1 communication path, the # 2 communication path, each having one end connected to the # 1, # 2, # 3, and # 4 cylinders arranged in series, The other ends of the # 3 communication path and the # 4 communication path are assembled at a collecting portion, and the collecting portion is connected to an exhaust pipe through a connection pipe that is opened and closed by an on-off valve, and the # 1 located outside the arrangement direction , Among the # 4 cylinders, burnt gas is supplied from one cylinder in the expansion stroke or exhaust stroke to one cylinder in the intake stroke or compression stroke through the # 1, # 4 communication path, and the arrangement direction Of the # 2 and # 3 cylinders located on the inner side of the cylinder from one cylinder in the expansion stroke or exhaust stroke to one cylinder in the intake stroke or compression stroke through the # 2 and # 3 communication passages An internal combustion engine for supplying gas, in addition to the # 1, # 4 communication path Intersects at an obtuse angle at the gathering portion, and the other end of the # 2, # 3 communication path intersects at an acute angle at the gathering portion and extends the other end of the # 2, # 3 communication path An internal combustion engine is proposed, characterized in that the connecting pipe is provided on a line.

  According to the first aspect of the present invention, the burned gas is supplied from one cylinder in the expansion stroke or exhaust stroke of the in-line multi-cylinder internal combustion engine to one cylinder in the intake stroke or compression stroke through the communication passage to thereby provide EGR. When performing the above, the shape of the communication path that connects the two cylinders that exchange the burned gas is set so that the time for the burned gas to pass therethrough is substantially equal. It is possible to send and receive a certain amount of burned gas without matching the lengths, and a stable EGR effect can be obtained while ensuring the layout of the communication path and shortening the total length of the communication path. .

  According to the configuration of the second aspect, among the # 1 and # 4 cylinders located outside the arrangement direction of the four cylinders of the in-line four-cylinder internal combustion engine, the intake stroke or the intake stroke from one cylinder in the expansion stroke or the exhaust stroke. Burned gas is supplied to one cylinder in the compression stroke via the # 1, # 4 communication passage, and among the # 2, # 3 cylinders located on the inner side in the arrangement direction, it is in the expansion stroke or the exhaust stroke. EGR is performed by supplying burned gas from one cylinder to one cylinder in the intake stroke or compression stroke via the # 2, # 3 communication path.

  At this time, even if the # 1 and # 4 communication paths communicating with the # 1 and # 4 cylinders that are separated from each other become long, the # 1 and # 4 communication paths intersect at an obtuse angle at the gathering portion. The burned gas flows smoothly, and the shortage of burned gas supply caused by the long # 1, # 4 communication path can be compensated.

  On the other hand, even if the # 2 and # 3 communication paths communicating with the # 2 and # 3 cylinders adjacent to each other become shorter, the # 2 and # 3 communication paths intersect at an acute angle at the gathering section, and # 2 and # 3 Because the connecting pipe connected to the exhaust pipe is provided on the extension line ahead of the collecting part of the # 3 communicating path, the burned gas is difficult to pass through the collecting part of the # 2 and # 3 communicating path and connected. Since the lengths of the # 2 and # 3 communication paths are substantially increased by the length of the pipe, it is possible to compensate for the excess amount of burned gas supplied due to the short # 2 and # 3 communication paths.

  In this way, even if the lengths of the # 1 to # 4 communication paths are different, a certain amount of burned gas can be exchanged between the # 1 and # 4 cylinders, ensuring the layout of the communication paths and ensuring communication. A stable EGR effect can be obtained while shortening the total length of the passage.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples of the present invention shown in the accompanying drawings.

  1 to 4 show an embodiment of the present invention, FIG. 1 is a diagram showing a schematic structure of an in-line four-cylinder internal combustion engine, FIG. 2 is a perspective view showing a structure of an exhaust system of the internal combustion engine, and FIG. Is a view in the direction of arrows 3 in FIG. 2, and FIG. 4 is a time chart showing characteristics of the opening / closing timing of the engine valve.

  As shown in FIG. 1, an in-line four-cylinder internal combustion engine E that compresses and ignites an air-fuel mixture in a low load region and sparks the air-fuel mixture by an ignition plug in a high load region includes a # 1 cylinder 11A arranged in series, A # 2 cylinder 11B, a # 3 cylinder 11C, and a # 4 cylinder 11D are provided. Each cylinder 11A to 11D is provided with an intake valve 12, a first exhaust valve 13a, a second exhaust valve 13b, a fuel injection valve 14, and a spark plug 15. The intake manifold 16 is connected to the four intake valves 12,..., The exhaust manifold 17 is connected to the four first exhaust valves 13a, and the # 1 communication path is connected to each of the four second exhaust valves 13b. 18A- # 4 communication path 18D is connected. The intake valves 12, the first exhaust valves 13 a, and the second exhaust valves 13 b are opened and closed by corresponding solenoids (not shown), and their valve timing and valve lift can be arbitrarily set.

  As is clear from FIG. 1 and FIGS. 2 and 3 together, the exhaust manifold 17 includes a plate-like mounting flange 19 coupled to the side wall of a cylinder head (not shown). Are connected to one end of # 1 exhaust single pipe 20A to # 4 exhaust single pipe 20D connected to # 1 cylinder 11A to # 4 cylinder 11D through first exhaust valves 13a... The other ends of the single pipes 20A to # 4 exhaust single pipe 20D are connected to the exhaust pipe 22 via the exhaust junction 21.

  One end of the # 1 communication path 18A to # 4 communication path 18D connected to the # 1 cylinder 11A to # 4 cylinder 11D is connected to the outer surface of the mounting flange 19 via the second exhaust valves 13b... The other ends of the communication passages 18A to # 4 communication passage 18D are gathered by the gathering portion 23 located between the # 2 cylinder 11B and the # 3 cylinder 11C, and then are connected via the L-shaped connecting pipe 24 and the opening / closing valve 25. Connected to the upper surface of the exhaust merging section 21. A butterfly-type valve body 26 is accommodated in the on-off valve 25, and this valve body 26 is connected to an output rod 28 of an actuator 27 to open and close. When the on-off valve 25 is opened, the collecting portion 23 of the # 1 communication passage 18A to # 4 communication passage 18D communicates with the exhaust merging portion 21 of the exhaust manifold 17, and when the on-off valve 25 is closed, the communication is established. Blocked.

  From the # 1 cylinder 11A to the # 4 cylinder 11D to the outer side of the arrangement direction and # 1 and # 4 extending from the # 4 cylinders 11A and 11D to the gathering portion 23 of the # 1 and # 4 communication paths 18A and 18D The length is a set of # 2 and # 3 communication passages 18B and 18C extending from # 2 and # 3 cylinders 11B and 11C which are adjacent to each other inside # 1 cylinder 11A to # 4 cylinder 11D in the arrangement direction. It is longer than the length up to the portion 23.

  As best shown in FIG. 3, the intersection angle α formed by the other ends of the # 1 and # 4 communication paths 18A and 18D gathering at the gathering portion 23 is an obtuse angle, and # 2 and # 3 gathering at the gathering portion 23 The intersection angle β formed by the other ends of the communication paths 18B and 18C is an acute angle. The connecting pipe 24 is positioned on the extension line of the other end of the # 2, # 3 communication paths 18B, 18C that gather at the gathering portion 23.

  Next, the operation of the embodiment having the above configuration will be described.

  During low load operation in which burned gas (EGR gas) is introduced from the other cylinders into the # 1 cylinder 11A to # 4 cylinder 11D and the mixture is compressed and ignited, the valve body 26 of the on-off valve 25 is closed by the actuator 27. , # 1 communication path 18A to # 4 communication path 18D are in a state where communication with exhaust pipe 22 is blocked.

  As shown in FIG. 4, the firing order of the # 1 cylinder 11A to the # 4 cylinder 11D is # 1 cylinder 11A → # 3 cylinder 11C → # 4 cylinder 11D → # 2 cylinder 11B, and continues to the intake manifold 16. The four intake valves 12 are opened in the intake stroke of the # 1 cylinder 11A to the # 4 cylinder 11D, and the four first exhausts connected to the # 1 exhaust single pipe 20A to the # 4 exhaust single pipe 20D of the exhaust manifold 17 are opened. The valves 13a are opened in the exhaust stroke of the # 1 cylinder 11A to the # 4 cylinder 11D. The four second exhaust valves 13b ... connected to the # 1 communication path 18A to the # 4 communication path 18D have a BDC between the expansion stroke and the exhaust stroke (hereinafter referred to as an expansion BDC) and a BDC between the intake stroke and the compression stroke. (Hereinafter referred to as intake BDC). That is, each of the intake valves 12 and the first exhaust valves 13a is opened once every two revolutions of the crankshaft, whereas each of the second exhaust valves 13b is opened once every revolution of the crankshaft. To do.

  The opening period of the second exhaust valve 13b in the expansion BDC of the # 1 cylinder 11A overlaps the opening period of the second exhaust valve 13b in the intake BDC of the # 4 cylinder 11D. During this period, the # 1 cylinder The burned gas is supplied from 11A to the # 4 cylinder 11D through the # 1 communication path 18A and the # 4 communication path 18D. Further, the opening period of the second exhaust valve 13b in the expansion BDC of the # 4 cylinder 11D overlaps with the opening period of the second exhaust valve 13b in the intake BDC of the # 1 cylinder 11A. Burned gas is supplied from the cylinder 11D to the # 1 cylinder 11A via the # 4 communication path 18D and the # 1 communication path 18A.

  Similarly, the valve opening period of the second exhaust valve 13b in the expansion BDC of the # 2 cylinder 11B overlaps the valve opening period of the second exhaust valve 13b in the intake BDC of the # 3 cylinder 11C. Burned gas is supplied from # 2 cylinder 11B to # 3 cylinder 11C through # 2 communication path 18B and # 3 communication path 18C. Further, the opening period of the second exhaust valve 13b... In the expansion BDC of the # 3 cylinder 11C and the opening period of the second exhaust valve 13b... In the intake BDC of the # 2 cylinder 11B overlap. Burned gas is supplied from the cylinder 11C to the # 2 cylinder 11B through the # 3 communication path 18C and the # 2 communication path 18B.

  When the burned gas is exchanged between the # 1 cylinder 11A and the # 4 cylinder 11D in this way, the first exhaust valve 13a ... and the second exhaust valve 13b ... of the # 2 cylinder 11B and the # 3 cylinder 11C are closed. When the burned gas is exchanged between the # 2 cylinder 11B and the # 3 cylinder 11C, the first exhaust valve 13a and the second exhaust valve 13b of the # 1 cylinder 11A and the # 4 cylinder 11D are closed. Since it is in the state, the burned gas is not exchanged unnecessarily between the # 1, # 4 cylinders 11A, 11D and the # 2, # 3 cylinders 11B, 11C.

  The # 1 communication passage 18A and the # 4 communication passage 18D for transferring burned gas between the # 1 cylinder 11A and the # 4 cylinder 11D are because the # 1 cylinder 11A and the # 4 cylinder 11D are separated from each other. Since it becomes long and the time for the burnt gas to pass therethrough becomes long, the supply amount of burnt gas may be insufficient. However, in this embodiment, the # 1 communication path 18A and the # 4 communication path 18D intersect each other at an obtuse angle α in the collecting portion 23, so that the burned gas passes smoothly through the collecting portion 23 in a short time. This makes it possible to compensate for the shortage of burned gas supply.

  On the other hand, the # 2 communication passage 18B and the # 3 communication passage 18C for transferring burned gas between the # 2 cylinder 11B and the # 3 cylinder 11C are because the # 2 cylinder 11B and the # 3 cylinder 11C are adjacent to each other. There is a possibility that the supply amount of burned gas becomes excessive because the time for burnt gas to pass through is shortened. However, in this embodiment, the # 2 communication path 18B and the # 3 communication path 18C intersect each other at an acute angle β in the collecting portion 23, and the extension lines of the # 2 communication path 18B and the # 3 communication path 18C are connected. Since the pipe 24 is oriented, it is difficult for the burned gas to smoothly pass through the collecting portion 23, and the substantial lengths of the # 2 communication path 18B and the # 3 communication path 18C are increased by the length of the connection pipe 24. Therefore, it is possible to compensate for an excessive supply amount of burned gas.

  Thus, even if the lengths of the # 1, # 4 communication paths 18A, 18D are different from the lengths of the # 2, # 3 communication paths 18B, 18C, they are exchanged between the # 1, # 4 cylinders 11A, 11D. The amount of burned gas and the amount of burned gas exchanged between the # 2 and # 3 cylinders 11B and 11C can be made uniform, and the operating state of the internal combustion engine E during low load operation can be stabilized. Can do. In addition, since the lengths of the # 1 communication path 18A to the # 4 communication path 18D do not have to be equalized, the total length of the # 1 communication path 18A to the # 4 communication path 18D can be shortened. Reduction and layout improvement can be achieved.

  In addition, since the internal combustion engine E during high-load operation is subjected to spark ignition operation by the normal spark plugs 15..., Burned gas is not exchanged between the # 1 cylinder 11A to the # 4 cylinder 11D. At this time, the valve body 26 of the on-off valve 25 is opened, the # 1 communication path 18A to the # 4 communication path 18 communicate with the exhaust pipe 22 at the exhaust junction 21, and the second exhaust valve 13b. It opens and closes at the same valve timing as the valves 13a. As a result, the # 1 communication path 18A to the # 4 communication path 18 can exhibit a function as an exhaust pipe.

  Since the intake valves 12, the first exhaust valves 13 a, and the second exhaust valves 13 b are opened and closed by solenoids, the valve timing during low load operation and the valve timing during high load operation are different as described above. Is possible.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. It is.

  For example, in the embodiment, burned gas is supplied from a cylinder in the expansion BDC between the expansion stroke and the exhaust stroke to a cylinder in the intake BDC between the intake stroke and the compression stroke. The burned gas may be supplied to the cylinder in the stroke, or the burned gas may be supplied from the cylinder in the exhaust stroke to the cylinder in the compression stroke.

  In the embodiment, a four-cylinder internal combustion engine is illustrated, but the present invention is also applicable to an internal combustion engine having five or more cylinders.

The figure which shows the general | schematic structure of an inline 4 cylinder internal combustion engine The perspective view which shows the structure of the exhaust system of an internal combustion engine 3 direction arrow view of FIG. Time chart showing characteristics of engine valve opening and closing timing

Explanation of symbols

11A # 1 cylinder (cylinder)
11B # 2 cylinder (cylinder)
11C # 3 cylinder (cylinder)
11D # 4 cylinder (cylinder)
18A # 1 communication path (communication path)
18B # 2 communication path (communication path)
18C # 3 communication path (communication path)
18D # 4 communication path (communication path)
22 Exhaust pipe 23 Collecting part 24 Connection pipe 25 On-off valve α Obtuse angle β Acute angle

Claims (2)

A plurality of communication passages (18A to 18D) having different lengths for communicating a plurality of cylinders (11A to 11D) arranged in series with each other are provided, and an expansion stroke or an exhaust gas among the plurality of cylinders (11A to 11D). In an internal combustion engine that supplies burned gas from one cylinder in a stroke to one cylinder in an intake stroke or a compression stroke through the communication path (18A to 18D),
The internal combustion engine characterized in that the communication passages (18A to 18D) for communicating the two cylinders for sending and receiving burnt gas are set so that the time for burnt gas to pass therethrough is substantially equal. . # 1 communication path (18A), # 2 stations connected at one end to # 1 cylinder (11A), # 2 cylinder (11B), # 3 cylinder (11C) and # 4 cylinder (11D) arranged in series, respectively The other end of the passage (18B), # 3 communication passage (18C) and # 4 communication passage (18D) is gathered at the gathering portion (23), and the gathering portion (23) is opened and closed by the on-off valve (25). Connected to the exhaust pipe (22) via the pipe (24),
Among the # 1, # 4 cylinders (11A, 11D) positioned outside in the arrangement direction, the # 1, # 4 is changed from one cylinder in the expansion stroke or the exhaust stroke to one cylinder in the intake stroke or the compression stroke. One of the # 2, # 3 cylinders (11B, 11C) that supplies burned gas via the communication passages (18A, 18D) and is located inside the arrangement direction is in the expansion stroke or the exhaust stroke. An internal combustion engine that supplies burned gas to one cylinder in an intake stroke or a compression stroke from the # 2 and # 3 communication passages (18B, 18C),
The other ends of the # 1, # 4 communication paths (18A, 18D) intersect at an obtuse angle (α) at the gathering portion (23), and other than the # 2, # 3 communication paths (18B, 18C). The ends intersect at an acute angle (β) at the gathering portion (23), and the connecting pipe (24) is provided on an extension line at the other end of the # 2, # 3 communication path (18B, 18C). An internal combustion engine characterized by the above.

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