JP6065763B2 - Exhaust gas recirculation device for vehicle engine - Google Patents

Description

  The present invention relates to an exhaust gas recirculation device for a vehicle engine, and is particularly suitable for an exhaust gas recirculation device in which an exhaust gas cooler is disposed in the middle of an exhaust gas recirculation passage.

  In a vehicle engine, for example, an exhaust gas recirculation device that recirculates a part of exhaust gas flowing through an exhaust pipe to an intake system is used for the purpose of preventing knocking or promoting warm air. For this reason, for example, there is a type in which an exhaust pipe and an intake manifold are connected by an exhaust gas recirculation passage, and an exhaust gas cooler for cooling the exhaust gas flowing through the exhaust gas recirculation passage is disposed in the middle of the exhaust gas recirculation passage. As an exhaust gas recirculation device for a vehicle engine in which an exhaust gas cooler is arranged in the middle of the exhaust gas recirculation passage as described above, for example, there is one described in Patent Document 1 below. In this exhaust gas recirculation device for a vehicle engine, an exhaust gas cooler is directly attached to the side surface of the cylinder head via an adapter. Further, the connection point between the exhaust gas cooler and the downstream pipe is disposed at the end of the cylinder head in the vehicle width direction and is far away from the exhaust manifold.

JP 2004-92443 A

  However, in the exhaust gas recirculation device for a vehicle engine described in Patent Document 1, only an exhaust gas cooler is directly attached to the side surface of the cylinder head. Therefore, when the vehicle travels in a cold region, There is a possibility that air or snow contained in the air directly contacts the exhaust gas cooler, cools the exhaust gas cooler, and freezes condensed water inside. Also, if the engine is stopped and left in a cold region, low-temperature air tends to enter the vicinity of the exhaust gas cooler, and sufficient heat from the exhaust manifold is difficult to be transmitted to the exhaust gas cooler, so that the exhaust gas cooler and exhaust gas cooler passages There is a risk that the condensed water will freeze inside. Furthermore, the connection point between the exhaust gas cooler and the downstream pipe is disposed at the end of the cylinder head in the vehicle width direction and is far away from the exhaust manifold. For this reason, there is a risk that low-temperature air or snow will come into direct contact with the connection point between the downstream pipe and the exhaust gas cooler, and the condensed water may freeze inside. There is a risk of freezing.

  The present invention has been made paying attention to the above-described problems, and an object of the present invention is to provide an exhaust gas recirculation device for a vehicle engine in which condensed water is difficult to freeze inside even in cold weather. .

  According to a first aspect of the present invention, there is provided an intake manifold having a plurality of intake branch pipes connected to a plurality of intake ports and attached to a front portion of the cylinder head in the vehicle longitudinal direction. An exhaust gas recirculation device for a vehicle engine comprising: an exhaust manifold having a plurality of exhaust branch pipes connected to each of a plurality of exhaust ports; and an exhaust pipe having a catalyst and connected to the exhaust manifold. The exhaust manifold is formed as a part of the exhaust manifold, and the exhaust manifold as a whole extends toward the front of the vehicle. The exhaust manifold is formed as a part of the exhaust manifold, and is bent from the front end of the horizontal portion of the vehicle. An exhaust manifold that passes through the exhaust pipe and is formed between a vertical portion that extends downward in the vehicle and the exhaust pipe and the intake manifold. An exhaust gas recirculation passage in which a portion recirculates to the intake manifold via the inside of the cylinder head, and the exhaust manifold and the engine body in a state where an upper portion is covered with the horizontal portion and a front portion is covered with the vertical portion. And an exhaust gas cooler that cools the exhaust gas that is disposed in the middle of the exhaust gas recirculation passage and flows inside the exhaust gas recirculation passage, and constitutes a part of the exhaust gas recirculation passage. A metal upstream exhaust gas recirculation pipe that communicates the exhaust pipe and the exhaust gas cooler; and a metal downstream that forms part of the exhaust gas recirculation passage and communicates the exhaust gas cooler and the cylinder head Side exhaust gas recirculation pipe, an exhaust gas inlet connected to the upstream side exhaust gas recirculation pipe and the exhaust gas cooler, and the exhaust gas cooler and the downstream side exhaust gas return An exhaust gas outlet connected to the pipe is disposed at the same height as the exhaust collecting part where the plurality of exhaust branch pipes are gathered, and the exhaust gas inlet is located in the vehicle width direction of the exhaust collecting part when viewed from the front of the vehicle. The exhaust gas outlet portion is disposed on the other side in the vehicle width direction of the exhaust collecting portion in a front view of the vehicle, and the exhaust gas inlet portion is below the exhaust branch pipe and the vehicle in the exhaust collecting portion. The exhaust gas outlet portion is arranged in the first space portion on one side in the width direction, and the exhaust gas outlet portion is arranged in the second space portion on the other side in the vehicle width direction of the exhaust collecting portion. And

  In the second aspect of the present invention, the catalyst is preferably disposed immediately below the exhaust collecting portion.

  According to a third aspect of the present invention, a cylinder head side connecting portion that connects the downstream exhaust gas recirculation pipe and the cylinder head is located above the exhaust gas outlet portion in the vehicle and the other side in the vehicle width direction of the exhaust manifold. The downstream exhaust gas recirculation pipe is disposed along the exhaust branch pipe from the exhaust gas outlet portion toward the cylinder head side coupling portion, and the downstream exhaust gas recirculation pipe of the downstream It is preferable to form a downstream bellows portion having a bellows shape at a portion where the side exhaust gas recirculation pipe and the exhaust branch pipe are closest to each other.

  According to a fourth aspect of the present invention, an exhaust pipe side connecting portion for connecting the exhaust pipe and the upstream exhaust gas recirculation pipe is disposed on the exhaust downstream side of the catalyst in the exhaust pipe, and the upstream exhaust gas is provided. A recirculation pipe is arranged along one side of the exhaust pipe in the vehicle width direction, and a portion of the upstream exhaust gas recirculation pipe that is closer to the exhaust gas inlet than the exhaust pipe side coupling portion has a bellows shape. It is preferable to form an upstream bellows portion.

  According to a fifth aspect of the present invention, a recess is formed in at least one of the exhaust branch pipe adjacent to the first space part and the exhaust collecting part, the recess being recessed on the passage side of the exhaust branch pipe in a front view of the vehicle. It is preferable to arrange the exhaust gas inlet in

  In the sixth aspect of the present invention, the exhaust gas cooler is preferably attached to a cylinder block at a vehicle rear position of the exhaust branch pipe and a vehicle rear position of the catalyst.

  Thus, according to the first aspect described above, the exhaust manifold is formed with a horizontal portion that extends toward the front of the vehicle as a part of the exhaust manifold, and is bent from the front end of the horizontal portion of the exhaust manifold. A vertical portion extending entirely downward in the vehicle is formed as a part of the exhaust manifold. Further, an exhaust gas recirculation passage through which a part of the exhaust gas passing through the exhaust pipe returns to the intake manifold via the inside of the cylinder head is formed between the exhaust pipe and the intake manifold. An exhaust gas cooler that is disposed in the middle of the exhaust gas recirculation passage and cools the exhaust gas flowing through the exhaust gas recirculation passage, with the upper part covered by the horizontal part and the front part covered by the vertical part and the engine Place in the space surrounded by the main body. Further, the exhaust pipe and the exhaust gas cooler are connected by a metal upstream exhaust gas recirculation pipe, and the exhaust gas cooler and the cylinder head are connected by a metal downstream exhaust gas recirculation pipe. And an exhaust gas inlet portion where the upstream side exhaust gas recirculation pipe and the exhaust gas cooler are connected, and an exhaust gas outlet portion where the exhaust gas cooler and the downstream side exhaust gas recirculation pipe are connected, an exhaust collecting portion where a plurality of exhaust branch pipes gather Place them at the same height. Further, the exhaust gas inlet portion is arranged on one side in the vehicle width direction of the exhaust collecting portion in front view of the vehicle, and the exhaust gas outlet portion is arranged on the other side in the vehicle width direction of the exhaust collecting portion in front view of the vehicle. Further, the exhaust gas inlet portion is disposed below the exhaust branch pipe and in the first space portion on one side in the vehicle width direction of the exhaust collecting portion, and the exhaust gas outlet portion is located below the exhaust branch pipe and the exhaust collecting portion. It arrange | positions in the 2nd space part of the vehicle width direction other side.

  Therefore, even when the engine is temporarily stopped during cold weather, the heat of the exhaust manifold and the engine body can be stored in the space between the exhaust manifold where the exhaust gas cooler is disposed and the engine body. As a result, the exhaust gas cooler can be heated by the heat accumulated between the exhaust manifold and the engine body during the time from when the engine is stopped and the time has elapsed until the engine is restarted. Therefore, even if the upstream exhaust gas recirculation pipe and the downstream exhaust gas recirculation pipe are made of metal having high thermal conductivity, the exhaust gas cooler, the upstream exhaust gas recirculation pipe, or the downstream exhaust gas recirculation pipe is not cooled during cold. It is possible to prevent the condensed water from being generated and the condensed water from being frozen. Further, when the vehicle travels in cold weather, the exhaust manifold can prevent low-temperature air or snow introduced from the front of the vehicle from directly blowing on the exhaust gas cooler. Also by this, it is possible to prevent the condensed water from being generated inside the exhaust gas cooler, the upstream side exhaust gas recirculation pipe or the downstream side exhaust gas recirculation pipe, or the condensed water from being frozen. In addition, at the connecting portion between the exhaust gas cooler and the upstream exhaust gas recirculation pipe or the downstream exhaust gas recirculation pipe, the upstream exhaust gas recirculation pipe and the downstream exhaust gas recirculation pipe are arranged horizontally, A large area difference may occur between the passage area and the passage area in the exhaust gas cooler. Condensed water tends to accumulate in portions where the exhaust gas recirculation pipes are horizontal, and the flow of exhaust gas stagnates in portions where the passage area difference is large, and condensed water tends to be generated. Also in these points, it is possible to prevent the condensed water from being generated or frozen in the exhaust gas cooler, the upstream side exhaust gas recirculation pipe, or the downstream side exhaust gas recirculation pipe. In addition, since the exhaust gas inlet and the exhaust gas outlet are arranged on both sides in the vehicle width direction of the exhaust collector in front of the vehicle across the exhaust collector, the exhaust gas inlet from the exhaust collector that is the hottest in the exhaust manifold. Heat is easily transferred to the exhaust part and the exhaust gas outlet part. Therefore, even if cold air or snow is excessively blown to the exhaust gas inlet and the exhaust gas outlet while the vehicle is running in cold weather, the exhaust gas inlet and the exhaust gas outlet are heated by the heat transferred from the exhaust gas collector. It is possible to prevent the condensed water from being generated inside the section or the condensed water from being frozen.

  Further, according to the second aspect, the exhaust gas cooler is positioned behind the catalyst by arranging the catalyst immediately below the exhaust collecting portion. As is well known, since the catalyst exhibits a sufficient exhaust gas purification function at a preset high temperature, the catalyst after the engine is stopped is at a high temperature, and the heat transferred from the high temperature catalyst causes the exhaust gas even in the cold. It is possible to prevent the condensed water from being generated or frozen in the gas cooler, the upstream side exhaust gas recirculation pipe or the downstream side exhaust gas recirculation pipe.

  Further, according to the third aspect, the cylinder head side connecting portion where the downstream side exhaust gas recirculation pipe and the cylinder head are connected is located above the exhaust gas outlet portion and on the other side in the vehicle width direction of the exhaust manifold. Deploy. Further, the downstream exhaust gas recirculation pipe is disposed along the exhaust branch pipe from the exhaust gas outlet portion toward the cylinder head side connecting portion, and among the downstream exhaust gas recirculation pipes, the downstream exhaust gas recirculation pipe and the exhaust branch pipe are arranged. A downstream bellows portion is formed at a portion closest to each other. Therefore, the amount of heat received by the downstream bellows portion from the exhaust branch pipe can be increased, and the entire downstream exhaust gas recirculation pipe is heated by the amount of heat, and in the vicinity of the exhaust gas outlet portion of the downstream exhaust gas recirculation pipe. Condensed water that tends to occur and its freezing can be prevented. Further, by providing the downstream bellows portion, the thermal expansion and contraction of the downstream exhaust gas recirculation pipe is facilitated, and the amount of heat received by the downstream exhaust gas recirculation pipe can be increased accordingly, and the downstream exhaust gas recirculation pipe It is possible to extend the life of the battery.

  Further, according to the fourth aspect, the exhaust pipe side connecting portion where the exhaust pipe and the upstream side exhaust gas recirculation pipe are connected is disposed on the exhaust downstream side of the catalyst of the exhaust pipe. Further, the upstream exhaust gas recirculation pipe is disposed along one side of the exhaust pipe in the vehicle width direction, and the upstream exhaust gas recirculation pipe is located upstream of the exhaust pipe side coupling portion and closer to the exhaust gas inlet. A bellows part is formed. Therefore, it is possible to increase the amount of heat that the upstream side bellows part receives from the exhaust gas inlet and the amount of heat that the upstream side exhaust gas recirculation pipe receives from the exhaust pipe. In the side exhaust gas recirculation pipe, it is possible to prevent condensed water that is likely to be generated in the vicinity of the exhaust gas inlet and freezing thereof. Further, by providing the upstream side bellows part, the thermal expansion and contraction of the upstream side exhaust gas recirculation pipe is facilitated, and the amount of heat received by the upstream side exhaust gas recirculation pipe can be increased by that amount, and the upstream side exhaust gas recirculation pipe It is possible to extend the life of the battery.

  Further, according to the fifth aspect, a recess is formed in at least one of the exhaust branch pipe and the exhaust collecting part adjacent to the first space part and is recessed on the passage side of the exhaust branch pipe in a front view of the vehicle. An exhaust gas inlet is arranged. For example, according to the fourth aspect, the overall length of the upstream exhaust gas recirculation pipe tends to be long, and there is a possibility that low-temperature air, snow, or the like is blown to the upstream exhaust gas recirculation pipe. However, by disposing the exhaust gas inlet part in the recess formed in at least one of the exhaust branch pipe and the exhaust collecting part, the exhaust gas inlet part can be brought close to the exhaust branch pipe or the exhaust collecting part and received from there. Condensed water that is likely to be generated near the exhaust gas inlet due to heat and its freezing can be prevented.

  According to the sixth aspect, the exhaust gas cooler is attached to the cylinder block at the vehicle rear position of the exhaust branch pipe and the vehicle rear position of the catalyst. As a result, the exhaust gas cooler can easily receive heat from the exhaust branch pipe and the catalyst, and it is possible to prevent the condensed water from being generated in the exhaust gas cooler or the condensed water from being frozen by the amount of heat.

FIG. 1 is a side view of a vehicle front portion showing an embodiment of a vehicle engine to which an exhaust gas recirculation device of the present invention is applied. FIG. 2 is a front view of the front portion of the vehicle shown in FIG. FIG. 3 is a plan view of the front portion of the vehicle shown in FIG. FIG. 4 is a front view of the engine of FIG. FIG. 5 is a plan view of the engine of FIG. 6 is a cross-sectional view taken along line XX in FIG. 7 is a YY cross-sectional view of FIG. 4 showing the vicinity of the exhaust gas cooler. FIG. 8 is an enlarged front view around the exhaust gas cooler. FIG. 9 is an enlarged front view showing an attached state of the exhaust gas cooler. FIG. 10 is an enlarged front view around the exhaust gas showing a modification of the present invention.

  Next, an embodiment of an exhaust gas recirculation device for a vehicle engine according to the present invention will be described with reference to the drawings. 1 is a side view of the front portion of the vehicle according to the present embodiment, FIG. 2 is a front view of the front portion of the vehicle in FIG. 1, and FIG. 3 is a plan view of the front portion of the vehicle in FIG. In the present embodiment, an engine room 1 is formed at the front of the vehicle, and an engine 2 is mounted in the engine room 1. In the engine 2, the cylinder head 4 is attached to the upper end surface of the cylinder block 3, and the cylinder head cover 5 is attached to the upper end surface of the cylinder head 4. A crankcase is formed in the lower part of the cylinder block 3, and the crankshaft 6 is rotatably accommodated in the crankcase. An oil pan 7 is attached to the lower end surface of the cylinder block 3. In the present embodiment, the transmission 8 is attached to the engine 2 on the right side of the drawing in FIG. Note that a so-called engine main part including the cylinder head 4, the cylinder block 3, the cylinder head cover 5, the oil pan 7, and the like is also referred to as an engine body.

  Inside the cylinder block 3, for example, as shown in FIG. 6, a plurality of, in the present embodiment, four cylinders 9 are formed in the axial direction of the crankshaft 6. A combustion chamber 10 is formed at each cylinder 9 end on the cylinder head 4 side. Therefore, the axis of the crankshaft 6 is parallel to the arrangement direction of the combustion chambers 10, that is, the cylinder rows. A piston (not shown) is disposed in each cylinder 9 and is connected to a crankpin of the crankshaft 6 via a connecting rod (connecting rod) 11. Since the crankpin is eccentric with respect to the axis of the crankshaft 6, when the piston reciprocates inside the cylinder 9, it is converted into rotational movement of the crankshaft 6 and transmitted to the transmission 8. Further, each combustion chamber 10 is connected to an intake port 12 for intake of air-fuel mixture into the combustion chamber 10 and an exhaust port 13 for exhausting exhaust gas from the combustion chamber 10. In the present embodiment, the intake port 12 is formed toward the rear of the vehicle with respect to the combustion chamber 10, and the exhaust port 13 is formed toward the front of the vehicle with respect to the combustion chamber 10.

  4 is a front view of the engine of FIG. 2, FIG. 5 is a plan view of the engine of FIG. 3, and FIG. 6 is a sectional view taken along line XX of FIG. In this embodiment, for example, as shown in FIG. 5, two intake ports 12 and two exhaust ports 13 are connected to each combustion chamber 10 or each cylinder 9 and orthogonal to the cylinder row direction of the cylinder head 4. In the outer wall portion in the direction in which they are directed, they are gathered for each combustion chamber 10 or each cylinder 9. That is, four intake ports 12 are opened on the vehicle rear side end surface of the cylinder head 4, and four exhaust ports 13 are opened on the vehicle front side end surface of the cylinder head 4. The openings of the intake ports 12 are connected to the intake branch pipes 15 of the intake manifold 14, and the openings of the exhaust ports 13 are connected to the exhaust branch pipes 17 of the exhaust manifold 16. Therefore, the intake manifold 14 has a plurality of intake branch pipes 15 corresponding to the number of openings of the intake port 12, that is, four, and the exhaust manifold 16 has a plurality of exhaust branch pipes 17 corresponding to the number of openings of the exhaust port 13, that is, four. . The intake branch pipe 15 of the intake manifold 14 is collected by an intake air collecting portion 18, connected to an air cleaner 20 via an intake connection pipe 19, and further connected to an intake duct (not shown). On the other hand, the exhaust branch pipe 17 of the exhaust manifold 16 is gathered at the exhaust gathering portion 21 and connected to the exhaust pipe 22. A catalyst 23 for purifying the exhaust gas is interposed in the exhaust pipe 22. In the present embodiment, the catalyst 23 is disposed immediately below the exhaust collecting portion 21. Note that the term “directly” here means immediately below. Further, the exhaust manifold 16 is bent from the front end of the horizontal portion 27 of the cylinder head 4 toward the vehicle front side of the cylinder head 4, and the exhaust manifold 16 by bending from the front end of the horizontal portion 27. Vertical portions 28 that extend in the downward direction of the vehicle as a whole are formed as part of the exhaust manifold 16.

  In the present embodiment, an exhaust gas recirculation passage 24 for returning a part of the exhaust gas flowing through the exhaust pipe 22 to the intake manifold 14 is formed between the exhaust pipe 22 and the intake manifold 14. A part of the exhaust gas recirculation passage 24 of this embodiment is formed inside the cylinder head 4, and is recirculated to the intake manifold 14 via the inside of the cylinder head 4. Exhaust gas that has passed through the exhaust gas recirculation passage 24 in the cylinder head 4 is recirculated to an intake manifold 14 from an exhaust gas recirculation valve (EGR valve) 25 attached to the cylinder head 4 via an exhaust gas recirculation pipe 26. The exhaust gas recirculation valve (EGR valve) 25 is a flow rate adjusting valve for adjusting the flow rate of the recirculated exhaust gas including whether or not the exhaust gas is recirculated.

  In the present embodiment, an exhaust gas cooler (EGR cooler) 29 for cooling the exhaust gas flowing in the exhaust gas recirculation passage 24 is arranged in the middle of the exhaust gas recirculation passage 24. 7 is a YY sectional view of FIG. 4 showing the periphery of the exhaust gas cooler 29, FIG. 8 is an enlarged front view of the periphery of the exhaust gas cooler 29, and FIG. 9 is an enlarged front view showing the mounting state of the exhaust gas cooler 29. is there. The exhaust gas cooler 29 of the present embodiment is a rectangle that is long in the vehicle width direction when viewed from the front of the vehicle, and two cooling water pipes 30 are connected to the right end of the figure in FIG. Of the two cooling water pipes 30, one is for cooling water supply and the other is for cooling water discharge, and the cooling water is supplied to the cooling water passage inside the exhaust gas cooler 29 to cool the exhaust gas.

  The exhaust gas cooler 29 is disposed in a space surrounded by the exhaust manifold 16 and the engine body in a state where the upper portion is covered by the horizontal portion 27 of the exhaust manifold 16 and the front portion is covered by the vertical portion 28 of the exhaust manifold 16. ing. At this time, as clearly shown in FIG. 8, the exhaust gas cooler 29 has a left end portion in the drawing, that is, a right end portion of the vehicle, as viewed from the front of the vehicle, on the right side of the exhaust collecting portion 21 of the exhaust manifold 16. That is, the exhaust gas cooler 29 is disposed on one side in the vehicle width direction, and the right end portion in the drawing, that is, the vehicle left end portion, is disposed on the vehicle left side of the exhaust collecting portion, that is, on the other side in the vehicle width direction. Further, as shown in FIG. 9, the rectangular exhaust gas cooler 29 that is long in the vehicle width direction when viewed from the front of the vehicle has an upper side portion and a lower side portion attached to the vehicle front side surface of the cylinder block 3. Among these, the upper side attachment portion 31 for attaching the upper side portion of the exhaust gas cooler 29 to the cylinder block 3 is attached to the cylinder block 3 on the vehicle rear side of the exhaust branch pipe 17 of the exhaust manifold 16. A lower side attachment portion 32 for attaching the lower side portion of the exhaust gas cooler 29 to the cylinder block 3 is attached to the cylinder block 3 on the vehicle rear side of the catalyst 23.

  In the present embodiment, the exhaust gas is recirculated from the exhaust pipe downstream of the catalyst 23 in the exhaust pipe 22, and the exhaust gas is exhausted from the cylinder block 3 to the right end shown in FIG. Reflux the gas. Therefore, as shown in FIG. 4, the exhaust pipe 22 on the exhaust downstream side of the catalyst 23 and the illustrated left end portion of the exhaust gas cooler 29, that is, the vehicle right end portion, are made of a metal upstream exhaust gas recirculation pipe 33. Contact us at Further, the right end portion of the exhaust gas cooler 29 shown in the drawing, that is, the left end portion of the vehicle, and the right end portion of the cylinder head 4 shown in the drawing, that is, the left end portion of the vehicle are connected by a metal downstream exhaust gas recirculation pipe 34. To do. Therefore, the upstream exhaust gas recirculation pipe 33 and the downstream exhaust gas recirculation pipe 34 constitute a part of the exhaust gas recirculation passage 24. As a result, the illustrated left end of the exhaust gas cooler 29 to which the upstream exhaust gas recirculation pipe 33 is connected, that is, the right end of the vehicle, becomes the exhaust gas inlet 35 for the exhaust gas cooler 29, and the downstream exhaust gas recirculation pipe. The exhaust gas cooler 29 connected to the exhaust gas cooler 29 shown in FIG.

  Therefore, in this embodiment, the exhaust gas inlet portion 35 is disposed on the right side of the exhaust collecting portion 21 in the vehicle front view, that is, one side in the vehicle width direction, and the exhaust gas outlet portion 36 is exhausted in the vehicle front view. It arrange | positions at the vehicle left side of the aggregate part 21, ie, the vehicle width direction other side. As a result, the exhaust gas inlet portion 35 is disposed below the exhaust branch pipe 17 and in the first space portion 37 on the vehicle right side of the exhaust collecting portion 21, that is, on one side in the vehicle width direction. Further, the exhaust gas outlet portion 36 is disposed in the second space 38 below the exhaust branch pipe 17 and on the left side of the exhaust collecting portion 21, that is, on the other side in the vehicle width direction. Further, in the present embodiment, the exhaust gas inlet portion 35 and the exhaust gas outlet portion 36 are arranged at the same height as the exhaust collecting portion 21.

  Further, in the present embodiment, as described above, the exhaust pipe side connecting portion 39 where the exhaust pipe 22 and the upstream side exhaust gas recirculation pipe 33 are connected is disposed on the exhaust downstream side of the catalyst 23 of the exhaust pipe 22. Yes. The upstream exhaust gas recirculation pipe 33 is arranged along the right side of the exhaust pipe 22 in the vehicle, that is, along one side in the vehicle width direction. An upstream bellows portion 40 having a bellows shape is formed in a portion of the upstream exhaust gas recirculation pipe 33 closer to the exhaust gas inlet portion 35 than the exhaust pipe side coupling portion 39. Further, the cylinder head side connecting portion 41 where the downstream side exhaust gas recirculation pipe 34 and the cylinder head 4 are connected is above the exhaust gas outlet portion 36 and on the left side of the exhaust manifold 16, that is, the other in the vehicle width direction. Arranged on the side. Further, the downstream side exhaust gas recirculation pipe 34 is disposed along the exhaust branch pipe 17 from the exhaust gas outlet part 36 toward the cylinder head side connection part 41. Further, in the downstream side exhaust gas recirculation pipe 34, a downstream side bellows portion 42 having a bellows shape is formed at a portion where the downstream side exhaust gas recirculation pipe 34 and the exhaust branch pipe 17 are closest to each other.

  As is well known, the exhaust gas contains water vapor. When the exhaust gas cooler 29, the upstream side exhaust gas recirculation pipe 33, and the downstream side exhaust gas recirculation pipe 34 are rapidly cooled during cold, for example after the engine is stopped, condensed water is generated inside. When this condensed water is further cooled, it may freeze and the inside may be clogged. When the upstream side exhaust gas recirculation pipe 33 and the downstream side exhaust gas recirculation pipe 34 are made of metal as in the present embodiment, the heat conductivity is higher than that of the non-metallic exhaust gas recirculation pipe, so that the inside is further increased. It is easy to cool and easily generate condensed water. Further, in the internal passage of the exhaust gas recirculation passage 24, the exhaust gas flow tends to stagnate at locations where the passage area changes greatly, that is, where the passage area difference is large, and the stagnation location is greatly affected by external cooling. Condensed water is likely to be generated. In addition, if there is a horizontal portion in the internal passage of the exhaust gas recirculation passage 24, the condensed water tends to accumulate in the horizontal portion.

  On the other hand, in the exhaust gas recirculation device for a vehicle engine according to the present embodiment, a horizontal portion 27 in which the entire exhaust manifold 16 extends toward the front of the vehicle is formed as a part of the exhaust manifold 16. A vertical portion 28 that is bent from the end portion and extends in the vehicle downward direction as a whole of the exhaust manifold 16 is formed as a part of the exhaust manifold 16. Further, an exhaust gas recirculation passage 24 is formed between the exhaust pipe 22 and the intake manifold 14 so that a part of the exhaust gas passing through the exhaust pipe 22 returns to the intake manifold 14 through the inside of the cylinder head 4. The exhaust gas cooler 29 that is disposed in the middle of the exhaust gas recirculation passage 24 and cools the exhaust gas flowing inside the exhaust gas recirculation passage 24 is covered with the horizontal portion 27 and the front portion with the vertical portion 28. And disposed in a space surrounded by the exhaust manifold 16 and the engine body. Further, the exhaust pipe 22 and the exhaust gas cooler 29 are connected by a metal upstream exhaust gas recirculation pipe 33, and the exhaust gas cooler 29 and the cylinder head 4 are connected by a metal downstream exhaust gas recirculation pipe 34. An exhaust gas inlet 35 connected to the upstream exhaust gas recirculation pipe 33 and the exhaust gas cooler 29 and an exhaust gas outlet 36 connected to the exhaust gas cooler 29 and the downstream exhaust gas recirculation pipe 34 are connected to the plurality of exhaust branch pipes 17. Are arranged at the same height as the exhaust collecting portion 21 where the gas gathers. Further, the exhaust gas inlet portion 35 is disposed on the right side of the exhaust collecting portion 21 in the vehicle front view, that is, one side in the vehicle width direction, and the exhaust gas outlet portion 36 is disposed on the left side of the exhaust collecting portion 21 in the vehicle front view. On the other side in the vehicle width direction. Further, the exhaust gas inlet portion 35 is disposed in the first space portion 37 below the exhaust branch pipe 17 and on the right side of the exhaust collecting portion 21, that is, one side in the vehicle width direction, and the exhaust gas outlet portion 36. Is disposed below the exhaust branch pipe 17 and in the second space 38 on the left side of the exhaust collecting portion 21, that is, on the other side in the vehicle width direction.

  Therefore, even when the engine 2 is temporarily stopped during cold weather, the heat of the exhaust manifold 16 and the engine body can be stored in the space between the exhaust manifold 16 where the exhaust gas cooler 29 is disposed and the engine body. . As a result, the exhaust gas cooler 29 can be heated by the heat accumulated between the exhaust manifold 16 and the engine body during the time from when the engine 2 is stopped and the time has elapsed until the engine 2 is restarted. . Therefore, even if the upstream side exhaust gas recirculation pipe 33 and the downstream side exhaust gas recirculation pipe 34 are made of a metal having high thermal conductivity, the exhaust gas cooler 29 or the upstream side exhaust gas recirculation pipe 33 or the downstream side exhaust gas during cold weather. It is possible to prevent the condensed water from being generated inside the gas reflux pipe 34 and the condensed water from being frozen. Further, when the vehicle travels in cold weather, the exhaust manifold 16 can prevent low-temperature air or snow introduced from the front of the vehicle from directly blowing onto the exhaust gas cooler 29. Also by this, it is possible to prevent the condensed water from being generated inside the exhaust gas cooler 29, the upstream side exhaust gas recirculation pipe 33, or the downstream side exhaust gas recirculation pipe 34, or the condensed water from being frozen. In addition, in the connecting portion between the exhaust gas cooler 29 and the upstream side exhaust gas recirculation pipe 33 or the downstream side exhaust gas recirculation pipe 34, the upstream side exhaust gas recirculation pipe 33 and the downstream side exhaust gas recirculation pipe 34 are arranged horizontally, A large area difference may occur between the passage area in the exhaust gas recirculation pipes 33 and 34 and the passage area in the exhaust gas cooler 29. As described above, the condensed water tends to accumulate in the portions where the exhaust gas recirculation pipes 33 and 34 are horizontal, and the exhaust gas flows stagnate easily in the portion where the passage area difference is large. Also in these points, it is possible to prevent the condensed water from being generated or frozen in the exhaust gas cooler 29, the upstream side exhaust gas recirculation pipe 33, or the downstream side exhaust gas recirculation pipe 34. . Further, since the exhaust gas inlet portion 35 and the exhaust gas outlet portion 36 are disposed on both sides of the exhaust collector portion 21 in the vehicle width direction as viewed from the front of the vehicle with the exhaust collector portion 21 interposed therebetween, the exhaust manifold having the highest temperature in the exhaust manifold 16 is disposed. Heat is easily transferred from the part 21 to the exhaust gas inlet part 35 and the exhaust gas outlet part 36. Therefore, even if cold air or snow is excessively blown to the exhaust gas inlet portion 35 and the exhaust gas outlet portion 36 while the vehicle is traveling in cold weather, the exhaust gas inlet portion 35 is heated by the heat transmitted from the exhaust collecting portion 21. In addition, it is possible to prevent the condensed water from being generated inside the exhaust gas outlet portion 36 and the condensed water from being frozen.

  Further, the exhaust gas cooler 29 is positioned behind the catalyst 23 by arranging the catalyst 23 directly below the exhaust collecting portion 21. That is, the exhaust gas cooler 29 is located behind the catalyst 23 and above the catalyst 23. As is well known, since the catalyst 23 exhibits a sufficient exhaust gas purification function at a preset high temperature, the catalyst 23 after the engine is stopped is at a high temperature, and the heat transferred from the high temperature catalyst 23 to the rear of the vehicle Condensed water is generated inside the exhaust gas cooler 29 or the upstream side exhaust gas recirculation pipe 33 or the downstream side exhaust gas recirculation pipe 34 even when it is cold, or the condensed water freezes due to the heat transferred from the catalyst 23 to the upper side of the vehicle. Can be prevented.

  The cylinder head side connecting portion 41 where the downstream exhaust gas recirculation pipe 34 and the cylinder head 4 are connected is located above the exhaust gas outlet portion 36 and on the right side of the exhaust manifold 16, that is, the other side in the vehicle width direction. To place. Further, the downstream exhaust gas recirculation pipe 34 is disposed along the exhaust branch pipe 17 from the exhaust gas outlet portion 36 toward the cylinder head side connecting portion 41, and the downstream exhaust gas recirculation among the downstream exhaust gas recirculation tubes 34. A downstream bellows portion 42 is formed in a portion where the pipe 34 and the exhaust branch pipe 17 are closest to each other. Therefore, the amount of heat received by the downstream bellows portion 42 from the exhaust branch pipe 17 can be increased, and the entire downstream exhaust gas recirculation pipe 34 is heated by the amount of heat, and the exhaust gas in the downstream exhaust gas recirculation pipe 34 is exhausted. Condensed water that is likely to be generated in the vicinity of the outlet portion 36 and its freezing can be prevented. Further, by providing the downstream bellows portion 42, the thermal expansion and contraction of the downstream exhaust gas recirculation pipe 34 is facilitated, and the amount of heat received by the downstream exhaust gas recirculation pipe 34 can be increased correspondingly, and the downstream exhaust gas can be increased. The life of the gas reflux pipe 34 can be extended.

  Further, an exhaust pipe side connecting portion 39 where the exhaust pipe 22 and the upstream side exhaust gas recirculation pipe 33 are connected is disposed on the exhaust downstream side of the catalyst 23 of the exhaust pipe 22. Further, the upstream side exhaust gas recirculation pipe 33 is disposed along the left side of the exhaust pipe 22, that is, along one side in the vehicle width direction, and the upstream side exhaust gas recirculation pipe 33 is more than the exhaust pipe side connecting portion 39. An upstream bellows portion 40 is formed in a portion near the exhaust gas inlet portion 35. Therefore, the amount of heat received by the upstream side bellows portion 40 from the exhaust gas inlet portion 35 and the amount of heat received by the upstream side exhaust gas recirculation pipe 33 from the exhaust pipe 22 can be increased. By heating, condensed water that is likely to be generated in the vicinity of the exhaust gas inlet 35 in the upstream exhaust gas recirculation pipe 33 and freezing thereof can be prevented. Further, by providing the upstream side bellows portion 40, the thermal expansion and contraction of the upstream side exhaust gas recirculation pipe 33 can be facilitated, and the amount of heat received by the upstream side exhaust gas recirculation pipe 33 can be increased by that amount, and the upstream side exhaust gas can be increased. The life of the gas reflux pipe 33 can be extended.

  Further, an exhaust gas cooler 29 is attached to the cylinder block 3 at the vehicle rear position of the exhaust branch pipe 17 and the vehicle rear position of the catalyst 23. As a result, the exhaust gas cooler 29 can easily receive heat from the exhaust branch pipe 17 and the catalyst 23, and it is possible to prevent the condensed water from being generated in the exhaust gas cooler 29 or the condensed water from being frozen by the amount of heat. .

  Next, a modified example of the exhaust gas recirculation device for the vehicle engine of the present embodiment will be described with reference to FIG. This modification is similar to FIG. 8 and has many equivalent components. Therefore, the same components are denoted by the same reference numerals, and detailed description thereof is omitted. In this modification, the exhaust branch pipe 17 and the exhaust collecting part 21 of the exhaust manifold 16 adjacent to the first space part 37 described above are recessed in the passage side of the exhaust branch pipe 17 in a front view of the vehicle, and a recess 43 is formed in that part. Formed. In addition, an exhaust gas inlet 35 which is a connecting portion between the upstream side exhaust gas recirculation pipe 33 and the exhaust gas cooler 29 is disposed in the recess 43. For example, as shown in FIG. 4, when an exhaust pipe side connecting portion 39, which is a connecting portion between the upstream side exhaust gas recirculation pipe 33 and the exhaust pipe 22, is disposed on the exhaust downstream side of the catalyst 23, The overall length tends to be long. Therefore, there is a possibility that low temperature air, snow, or the like is blown onto the upstream side exhaust gas recirculation pipe 33. On the other hand, in this modification, the exhaust gas inlet portion 35 is disposed in a concave portion 43 in which the exhaust branch pipe 17 and the exhaust collecting portion 21 are recessed toward the passage side of the exhaust branch pipe 17 in a front view of the vehicle. Therefore, the exhaust gas inlet portion 35 can be brought close to the exhaust branch pipe 17 and the exhaust collecting portion 21, and condensed water that is likely to be generated near the exhaust gas inlet portion 35 due to heat received from the exhaust gas and the freezing thereof can be prevented. it can. The concave portion 43 may be formed in at least one of the exhaust branch pipe 17 and the exhaust collecting portion 21 adjacent to the first space portion 37. In this case, the exhaust gas inlet portion 35 is an exhaust gas in which the concave portion 43 is formed. It is possible to approach the branch pipe 17 or the exhaust collecting portion 21, and it is possible to prevent condensed water that is likely to be generated near the exhaust gas inlet portion 35 due to heat received from the branch pipe 17 or freezing thereof.

  Although the embodiments of the present invention have been disclosed above, it will be apparent to those skilled in the art that changes can be made without departing from the scope of the present invention. All such modifications and equivalents are intended to be included in the following claims.

DESCRIPTION OF SYMBOLS 1 Engine room 2 Engine 3 Cylinder block 4 Cylinder head 5 Cylinder head cover 6 Crankshaft 7 Oil pan 8 Transmission 9 Cylinder 10 Combustion chamber 11 Connecting rod (connecting rod)
DESCRIPTION OF SYMBOLS 12 Intake port 13 Exhaust port 14 Intake manifold 15 Intake branch pipe 16 Exhaust manifold 17 Exhaust branch pipe 18 Intake collecting part 19 Intake connecting pipe 20 Air cleaner 21 Exhaust collecting part 22 Exhaust pipe 23 Catalyst 24 Exhaust gas recirculation passage 25 Exhaust gas recirculation valve ( EGR valve)
26 Exhaust gas recirculation pipe 27 Horizontal portion 28 Vertical portion 29 Exhaust gas cooler (EGR cooler)
30 Cooling water piping 31 Upper side attachment portion 32 Lower side attachment portion 33 Upstream exhaust gas recirculation pipe 34 Downstream exhaust gas recirculation pipe 35 Exhaust gas inlet portion 36 Exhaust gas outlet portion 37 First space portion 38 Second space portion 39 Exhaust gas Pipe side connection part 40 Upstream side bellows part 41 Cylinder head side connection part 42 Downstream side bellows part 43 Recessed part

Claims (6)

An intake manifold having a plurality of intake branch pipes attached to the rear part of the cylinder head in the vehicle front-rear direction and connected to each of the plurality of intake ports, and attached to a front part of the cylinder head in the vehicle front-rear direction, to each of the plurality of exhaust ports An exhaust gas recirculation device for a vehicle engine, comprising an exhaust manifold having a plurality of exhaust branch pipes to be connected, and an exhaust pipe having a catalyst and connected to the exhaust manifold,
A horizontal portion formed as part of the exhaust manifold, the entire exhaust manifold extending toward the front of the vehicle;
A vertical portion formed as a part of the exhaust manifold, bent from the vehicle front end of the horizontal portion, and the exhaust manifold as a whole extends downward in the vehicle;
An exhaust gas recirculation passage formed between the exhaust pipe and the intake manifold, and a part of the exhaust gas passing through the exhaust pipe returns to the intake manifold via the inside of the cylinder head;
Arranged in the space surrounded by the exhaust manifold and the engine body with the upper part covered by the horizontal part and the front part covered by the vertical part, and arranged in the middle of the exhaust gas recirculation passage. An exhaust gas cooler for cooling the exhaust gas flowing in the gas recirculation passage;
A part of the exhaust gas recirculation passage, and a metal upstream exhaust gas recirculation pipe connecting the exhaust pipe and the exhaust gas cooler;
Comprising a part of the exhaust gas recirculation passage, and a metal downstream exhaust gas recirculation pipe communicating the exhaust gas cooler and the cylinder head,
Exhaust gas in which the plurality of exhaust branch pipes gather at an exhaust gas inlet portion where the upstream exhaust gas recirculation pipe and the exhaust gas cooler are connected and an exhaust gas outlet portion where the exhaust gas cooler and the downstream exhaust gas recirculation pipe are connected Place it at the same height as the gathering part,
The exhaust gas inlet portion is arranged on one side in the vehicle width direction of the exhaust collecting portion in a vehicle front view, and the exhaust gas outlet portion is arranged on the other side in the vehicle width direction of the exhaust collecting portion in a vehicle front view,
The exhaust gas inlet is disposed below the exhaust branch pipe and in the first space on one side in the vehicle width direction of the exhaust collecting section, and the exhaust gas outlet is below the exhaust branch pipe and An exhaust gas recirculation device for a vehicle engine, wherein the exhaust gas recirculation device is disposed in a second space portion on the other side in the vehicle width direction of the exhaust collecting portion.   2. The exhaust gas recirculation device for a vehicle engine according to claim 1, wherein the catalyst is disposed immediately below the exhaust collecting portion. A cylinder head side connecting portion for connecting the downstream exhaust gas recirculation pipe and the cylinder head is disposed above the exhaust gas outlet portion and on the other side in the vehicle width direction of the exhaust manifold;
The downstream exhaust gas recirculation pipe is disposed along the exhaust branch pipe from the exhaust gas outlet portion toward the cylinder head side connecting portion,
3. A downstream bellows portion having a bellows shape is formed in a portion of the downstream exhaust gas recirculation pipe closest to the downstream exhaust gas recirculation pipe and the exhaust branch pipe. An exhaust gas recirculation device for a vehicle engine as described in 1. An exhaust pipe side connecting portion for connecting the exhaust pipe and the upstream side exhaust gas recirculation pipe is disposed on the exhaust downstream side of the catalyst of the exhaust pipe,
The upstream exhaust gas recirculation pipe is disposed along one side of the exhaust pipe in the vehicle width direction,
4. An upstream bellows portion having a bellows shape is formed in a portion of the upstream exhaust gas recirculation pipe closer to the exhaust gas inlet portion than the exhaust pipe side connection portion. The exhaust gas recirculation device for a vehicle engine according to claim 1. At least one of the exhaust branch pipe and the exhaust collecting part adjacent to the first space part is formed with a concave part recessed on the passage side of the exhaust branch pipe in a front view of the vehicle, and the exhaust gas inlet part is disposed in the concave part. The exhaust gas recirculation device for a vehicle engine according to claim 4. The exhaust gas recirculation of the vehicle engine according to any one of claims 1 to 5, wherein the exhaust gas cooler is attached to a cylinder block at a vehicle rear position of the exhaust branch pipe and a vehicle rear position of the catalyst. apparatus.

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