JP2008111373A - Engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine with an EGR gas passage formed inside a cylinder block. <P>SOLUTION: This engine 1 is constituted so as to recirculate a part of exhaust gas exhausted from an exhaust manifold 2 to an intake manifold 3 as EGR gas, and is formed as a structure for covering the periphery of a gas recirculating passage 10 with a water jacket 11, by forming the gas recirculating passage 10 inside the cylinder block 6 between the exhaust manifold 2 and the intake manifold 3. The exhaust manifold 2 is integrally formed with an outlet passage 2a connected to the gas recirculating passage 10. The intake manifold 3 is connected to an inlet passage 3a via an EGR valve 4 from the gas recirculating passage 10, and the inlet passage 3a is integrally formed with the intake manifold 3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an engine technology, and more particularly to an engine technology configured to recirculate a part of exhaust gas discharged from an exhaust manifold to an intake manifold as EGR gas.

  Conventionally, in order to reduce nitrogen oxide (NOx) generated during engine combustion, an EGR device that recirculates (EGR) part of exhaust gas to the intake side is known. Nitrogen oxides are formed by the reaction of oxygen and nitrogen in the air under high-temperature exhaust gas, so this EGR device suppresses the generation of nitrogen oxides by reducing the combustion temperature by exhaust gas recirculation. . It has been experimentally shown that the EGR device reduces the generation of nitrogen oxides during combustion as the temperature of the exhaust gas recirculated to the intake side decreases.

Therefore, recently, an EGR device is known in which a water-cooled cooler is attached to an EGR pipe connecting an intake passage and an exhaust passage of an engine. The said cooler cools exhaust gas using the cooling water of a radiator.
JP-A-8-261072

Conventional engines have a structure in which an EGR pipe is used to connect between an intake passage and an exhaust passage, and exhaust gas is recirculated to the intake side to reduce exhaust emissions. However, when an EGR pipe is used, since the pipe length of the EGR pipe becomes long, stress due to vibration or thermal strain becomes a problem and there is a risk of damage. In addition, because piping outside the engine, there are cases where the arrangement of the engine is limited depending on the mounting state. In addition, the number of parts is increased with respect to an engine without an EGR device, and the number of assembly steps is increased accordingly, resulting in high cost. Further, when the EGR cooler is not used, the high temperature EGR gas is directly mixed into the intake air, so that the exhaust emission reduction effect is reduced.
Therefore, in view of such problems, the present invention provides an engine in which an EGR gas passage is formed inside a cylinder block.

  The problems to be solved by the present invention are as described above. Next, means for solving the problems will be described.

  That is, in claim 1, in an engine configured to recirculate a part of the exhaust gas discharged from the exhaust manifold to the intake manifold as EGR gas, inside the cylinder block between the exhaust manifold and the intake manifold, A gas reflux passage is formed, and the periphery of the gas reflux passage is covered with a water jacket.

  According to a second aspect of the present invention, the exhaust manifold is formed integrally with an outlet passage connected to the gas recirculation passage.

  According to a third aspect of the present invention, the intake manifold is connected to an inlet passage from the gas recirculation passage through an EGR valve, and the inlet passage is formed integrally with the intake manifold.

  The exhaust manifold and the gas recirculation passage are connected by an exhaust EGR pipe, and the EGR valve directly connected to the intake manifold and the gas recirculation passage are connected by an intake EGR pipe. It is.

  According to a fifth aspect of the present invention, the gas recirculation passage is disposed so as to be inclined so that either the intake side or the exhaust side is downward, and a condensate pool is provided in a cylinder block below the lower side of the gas recirculation passage. A discharge port is formed between the condensate reservoir and the outside.

  According to a sixth aspect of the present invention, the gas recirculation passage is disposed so as to be inclined so that either the intake side or the exhaust side is downward, and a condensate pool is provided at a lower portion of the passage connected to the lower side of the gas recirculation passage. And a discharge port is formed in the lower part of the condensed water reservoir.

  As effects of the present invention, the following effects can be obtained.

  In claim 1, since the pipe is not used, there is no fear of breakage and the reliability is improved. Moreover, since no pipe is used, an increase in the number of parts can be suppressed, and an increase in the number of assembly steps and an increase in cost can be suppressed. In addition, since no pipe is used, the state of the outer shape of the engine can be maintained, and the degree of freedom of the engine mounting position is improved. Further, since the exhaust gas is cooled by the cooling water in the cylinder block, it plays the role of a simple EGR cooler and the exhaust emission reduction effect is improved.

  According to the second aspect of the present invention, since the outlet passage is integrally formed, the number of parts can be reduced, the number of connecting portions is reduced, and the reliability is improved. In addition, the number of assembly steps can be reduced and the cost can be reduced.

  According to the third aspect of the present invention, since the inlet passage is integrally formed, the number of parts can be reduced, the number of connecting portions is reduced, and the reliability is improved. In addition, the number of assembly steps can be reduced and the cost can be reduced.

  According to the fourth aspect of the present invention, the lengths of the exhaust-side and intake-side EGR pipes can be shortened, and stress due to vibration and thermal strain can be reduced. Further, since the pipe is not disposed outside the engine, the outer shape of the engine can be maintained, and the degree of freedom of the engine mounting position is improved.

  According to the fifth aspect, since the condensed water is collected at a predetermined place, it is easy to take measures such as increasing the thickness of the peripheral portion of the condensed water reservoir, and the reliability is improved. Moreover, since the accumulated water can be easily discharged by providing a drain cock or the like at the discharge port, corrosion can be avoided by simple maintenance, and reliability is improved.

  According to the sixth aspect of the present invention, the condensed water can be stored in a condensed water reservoir formed outside the cylinder block, the accumulated water can be easily discharged, and maintenance can be easily performed.

Next, embodiments of the invention will be described.
FIG. 1 is a perspective view showing an overall configuration of an engine according to an embodiment of the present invention, FIG. 2 is a perspective view showing an exhaust manifold, FIG. 3 is a perspective view showing an intake manifold, and FIG. FIG. 5 is a side sectional view showing a gas recirculation passage, FIG. 6 is a perspective view showing an overall configuration of an engine according to an embodiment of the present invention, and FIG. 7 is an exhaust manifold. FIG. 8 is a perspective view showing an intake manifold, FIG. 9 is a front view showing a gas recirculation passage, FIG. 10 is a front view showing a gas recirculation passage, and FIG. 11 shows a conventional gas recirculation device. FIG.

Conventionally, as shown in FIG. 11, an exhaust manifold 102 and an intake manifold 103 are provided on both sides of the cylinder head at the top of the engine 101, and an EGR valve 104 is provided above the intake manifold 103. It is possible to adjust the amount of exhaust gas flowing from the side to the intake side. The exhaust manifold 102 and the EGR valve 104 are connected using an EGR pipe 105, and the exhaust gas is recirculated to the intake side to reduce the exhaust emission. However, when the EGR pipe 105 is used, since the pipe length of the EGR pipe becomes long, stress due to vibration or thermal strain becomes a problem, and there is a risk of damage. In addition, because piping outside the engine, there are cases where the arrangement of the engine is limited depending on the mounting state. In addition, the number of parts is increased with respect to an engine without an EGR device, and the number of assembly steps is increased accordingly, resulting in high cost. Further, when the EGR cooler is not used, the high temperature EGR gas is directly mixed into the intake air, so that the exhaust emission reduction effect is reduced.
Accordingly, in order to solve such a problem, the present invention describes an engine in which an EGR gas passage is formed inside a cylinder block.

An engine 1 according to an embodiment of the present invention is shown in FIGS.
As shown in FIG. 1, the engine 1 has a cylinder head 7 fixed to an upper portion of a cylinder block 6, and an exhaust manifold 2 and an intake manifold 3 are fixed on both sides of the cylinder head 7. An intake valve, an exhaust valve, and the like are disposed on the cylinder head 7, and a valve arm and the like are disposed on the cylinder head 7. The valve arm and the like are covered with a valve arm cover 8 to form a valve arm chamber. .
An air cleaner is connected to the intake manifold 3 so that the purified air can be sucked in, and a muffler is connected to the exhaust manifold 2 to reduce noise. Further, an EGR valve 4 is provided at the lower part of the intake manifold 3 so that the amount of exhaust gas flowing from the exhaust side to the intake side can be adjusted and closed at a low temperature or the like. I have to.

  As shown in FIG. 2, the exhaust manifold 2 is integrally formed with an outlet passage 2a for guiding a part of the exhaust gas to a gas recirculation passage 10 for sending a part of the exhaust gas to the intake side. 2 protrudes downward from the lower surface of one side, and the tip of the outlet passage 2a is connected to one end of a gas recirculation passage 10 provided in the engine 1 from the side of the cylinder block 6. On the other hand, as shown in FIG. 3, the intake manifold 3 is integrally formed with an inlet passage 3 a connected to the EGR valve 4, and the inlet passage 3 a is fixed to the lower surface of one end of the intake manifold 3. The other (lower end) is connected to one side of the EGR valve 4, and the other side of the EGR valve 4 is connected to the gas recirculation passage 10 provided in the engine 1 from the side of the cylinder block 6. The solenoid of the EGR valve 4 is connected to a control device, and is controlled to be opened and closed at the outside air temperature or at the time of starting. Thereby, since the exhaust manifold 2 and the intake manifold 3 are communicated without using a pipe, there is no fear of damage to the gas recirculation passage, and the reliability is improved. Moreover, the state of the outer shape of the engine can be maintained, and the degree of freedom of the engine mounting position is improved.

  The gas recirculation passage 10 is integrally formed with the water jacket 11 by casting when the cylinder block 6 is manufactured. Thereby, since a gas recirculation passage can be provided without adding new parts, an increase in the number of parts can be suppressed, and an increase in the number of assembly steps and an increase in cost can be suppressed.

  As shown in FIGS. 4 and 5, the gas recirculation passage 10 is formed in the cylinder block 6 in the horizontal direction, and communicates the exhaust manifold 2 and the intake manifold 3 (EGR valve 4) arranged on both sides with the shortest distance. Playing a role. The gas recirculation passage 10 is disposed outside a water jacket 11 formed in the cylinder block 6, and the water jacket 11 covers the periphery of the gas recirculation passage 10 as seen in a side sectional view shown in FIG. It is arranged. Thus, by flowing the cooling water from the radiator through the water jacket 11, the exhaust gas flowing in the gas recirculation passage 10 is cooled, thereby serving as a simple EGR cooler and improving the exhaust emission reduction effect. .

Next, an engine according to another embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 6, the exhaust manifold 2 and the intake manifold 3 are fixed on both sides of the cylinder head 7 fixed on the cylinder block 6. An intake valve, an exhaust valve, and the like are disposed on the cylinder head 7, and a valve arm and the like are disposed on the cylinder head 7. The valve arm and the like are covered with a valve arm cover 8 to form a valve arm chamber. . Further, an EGR valve 4 is provided on the side of one end in the longitudinal direction of the intake manifold 3, and can be adjusted by opening and closing the amount of exhaust gas flowing from the exhaust side to the intake side. Yes.

  As shown in FIG. 7, at the lower part of one end in the longitudinal direction of the exhaust manifold 2, one end of an exhaust side EGR pipe 2b for guiding exhaust gas from the exhaust manifold 2 to a gas recirculation passage 10 provided in the cylinder block 6 is provided. Are connected, and the other end communicates with the gas recirculation passage 10 from the side of the cylinder block 6. On the other hand, as shown in FIG. 8, in order to connect the EGR valve 4 provided on the side portion of the intake manifold 3 and the gas recirculation passage 10, an intake side EGR pipe 3b is provided in communication therebetween. . By providing the gas recirculation passage in the cylinder block 6 in this way, the length of the exhaust-side and intake-side EGR pipes can be shortened, and stress due to vibration and thermal strain can be reduced, so that the reliability of the pipes is improved.

  Further, the gas recirculation passage 10 is formed by casting together with the water jacket 11 when the cylinder block 6 is manufactured, as described above. Thereby, since a gas recirculation passage can be provided without adding new parts, an increase in the number of parts can be suppressed, and an increase in the number of assembly steps and an increase in cost can be suppressed.

  As shown in FIGS. 5 and 6, the gas recirculation passage 10 is provided in the cylinder block 6 and plays a role of connecting the exhaust manifold 2 and the intake manifold 3 (EGR valve 4). The gas recirculation passage 10 is disposed so as to be covered with a water jacket 11. Since the exhaust gas in the gas recirculation passage 10 is cooled by the cooling water flowing through the water jacket 11, it plays a role of a simple EGR cooler and the exhaust emission reduction effect is improved.

Next, another embodiment according to the present invention will be described with reference to FIGS.
As shown in FIG. 9, the gas recirculation passage 10 provided in the cylinder block 6 is horizontally oriented from the inlet of the exhaust gas, that is, the side connected to the exhaust manifold 2 to the side connected to the intake manifold 3. However, a condensate pool 20 is provided at a lower portion on one side of the gas recirculation passage 10, and a lower surface of the gas recirculation passage 10 is inclined downward toward the condensate pool 20. In the present embodiment, the lower inner surface 10 a of the gas recirculation passage 10 is formed to be inclined so as to descend from the EGR gas inlet from the exhaust manifold 2 toward the outlet to the intake manifold 3. A concave condensate pool 20 is formed at the lower side of the intake manifold 3 to collect the liquid obtained by condensing moisture in the exhaust gas downward. A drainage passage communicates from the bottom of the condensate pool 12 toward the outside of the engine, and a drain cock 21 is provided on the outlet side of the drainage passage.

The drain cock 21 can open and close to drain water accumulated in the condensed water reservoir 20. Therefore, it is possible to discharge the condensed water accumulated in the condensed water reservoir by opening the drain cock 21 as appropriate. Thus, by condensing the condensed water in the condensed water reservoir, the cylinder block 6 can be cooled as cooling water or by heat of vaporization, and the EGR gas can also be cooled. Moreover, since the drain water is easily provided by providing a drain cock at the discharge port, corrosion can be avoided by simple maintenance, and reliability is improved.
In the present embodiment, the height on the exhaust manifold 2 side is increased. However, the height on the intake manifold 3 side may be increased.

Moreover, as shown in FIG. 10, the condensed water pool 20 can also be provided in the channel | path connected to the low side of a gas recirculation | reflux channel | path. In FIG. 10, the lower inner surface 10 a of the gas recirculation passage 10 is configured to be lower on the intake manifold 3 side, and a condensed water reservoir 20 is provided on the lower side of the midway portion of the intake side EGR pipe 3 b connected to the intake manifold 3. A drain cock 21 is provided below the condensate pool. By opening and closing the drain cock 21, the water inside the condensed water reservoir 20 can be drained. Thereby, the condensed water can be stored in a condensed water reservoir formed outside the cylinder block, the accumulated water can be easily discharged, and maintenance can be simplified.
In the present embodiment, the height on the exhaust manifold 2 side is increased, but the height on the intake manifold 3 side may be increased, and the condensate pool 20 may be provided on the exhaust side EGR pipe 2b.

  As described above, the engine 1 according to the present embodiment is configured so that a part of the exhaust gas discharged from the exhaust manifold 2 is recirculated to the intake manifold 3 as EGR gas. A gas recirculation passage 10 is formed in the cylinder block 6 between the manifold 3 and the periphery of the gas recirculation passage 10 is covered with a water jacket 11. By configuring in this way, since a pipe is not used, there is no fear of breakage and reliability is improved. Moreover, since no pipe is used, an increase in the number of parts can be suppressed, and an increase in the number of assembly steps and an increase in cost can be suppressed. In addition, since no pipe is used, the state of the outer shape of the engine can be maintained, and the degree of freedom of the engine mounting position is improved. Further, since the exhaust gas is cooled by the cooling water in the cylinder block, it plays the role of a simple EGR cooler and the exhaust emission reduction effect is improved.

  The exhaust manifold 2 is integrally formed with an outlet passage 2 a connected to the gas recirculation passage 10. By configuring in this way, the outlet passage is integrally formed, so that the number of parts can be reduced, the number of connecting portions is reduced, and the reliability is improved. In addition, the number of assembly steps can be reduced and the cost can be reduced.

  The intake manifold 3 is connected to the inlet passage 3 a from the gas recirculation passage 10 via the EGR valve 4, and the inlet passage 3 a is formed integrally with the intake manifold 3. By configuring in this way, the inlet passage is integrally formed, so that the number of parts can be reduced, the number of connecting portions is reduced, and the reliability is improved. In addition, the number of assembly steps can be reduced and the cost can be reduced.

  The exhaust manifold 2 and the gas recirculation passage 10 are connected by an exhaust side EGR pipe 2b, and the EGR valve 4 directly connected to the intake manifold 3 and the gas recirculation passage 10 are connected by an intake side EGR pipe 3b. Is. By configuring in this way, the lengths of the exhaust-side and intake-side EGR pipes can be shortened, and stress due to vibration and thermal strain can be reduced, thereby improving the reliability of the pipes. Further, since the pipe is not disposed outside the engine, the outer shape of the engine can be maintained, and the degree of freedom of the engine mounting position is improved.

  Further, the gas recirculation passage 10 is disposed so as to be inclined so that either the intake side or the exhaust side is downward, and a condensed water reservoir 20 is placed in the cylinder block 6 below the lower side of the gas recirculation passage 10. A discharge port 21 is formed between the condensed water reservoir 20 and the outside. By configuring in this way, the condensed water accumulates at a predetermined location, so that it becomes easy to cope with increasing the thickness of the surrounding portion of the condensed water reservoir, and the reliability is improved. Moreover, since the accumulated water can be easily discharged by providing a drain cock or the like at the discharge port, corrosion can be avoided by simple maintenance, and reliability is improved.

  The gas recirculation passage 10 is disposed so as to be inclined so that either the intake side or the exhaust side is downward, and a condensate pool 20 is formed in a lower portion of the passage connected to the lower side of the gas recirculation passage 10. In addition, a discharge port 21 is formed in the lower part of the condensed water reservoir 20. With this configuration, the condensed water can be stored in a condensed water reservoir formed outside the cylinder block, the accumulated water can be easily discharged, and maintenance can be easily performed.

1 is a perspective view showing an overall configuration of an engine according to an embodiment of the present invention. The perspective view which showed the exhaust manifold. The perspective view which showed the intake manifold. The plane sectional view showing the gas recirculation passage. Side surface sectional drawing which showed the gas recirculation | reflux channel | path. 1 is a perspective view showing an overall configuration of an engine according to an embodiment of the present invention. The perspective view which showed the exhaust manifold. The perspective view which showed the intake manifold. The front view which showed the gas recirculation | reflux path | route. The front view which showed the gas recirculation | reflux path | route. The perspective view which showed the conventional gas recirculation | reflux apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 2 Exhaust manifold 3 Intake manifold 4 EGR valve 10 Gas recirculation passage 11 Water jacket 20 Condensate pool 21 Drain cock

Claims (6)

  In an engine configured to recirculate a part of the exhaust gas discharged from the exhaust manifold to the intake manifold as EGR gas, a gas recirculation passage is formed inside the cylinder block between the exhaust manifold and the intake manifold, An engine characterized by having a structure in which a gas jacket is surrounded by a water jacket.   The engine according to claim 1, wherein the exhaust manifold is integrally formed with an outlet passage connected to the gas recirculation passage.   The engine according to claim 1, wherein the intake manifold is connected to an inlet passage from the gas recirculation passage via an EGR valve, and the inlet passage is formed integrally with the intake manifold.   The exhaust manifold and the gas recirculation passage are connected by an exhaust side EGR pipe, and the EGR valve directly connected to the intake manifold and the gas recirculation passage are connected by an intake side EGR pipe. The engine according to 1.   The gas recirculation passage is disposed so as to be inclined so that either the intake side or the exhaust side is downward, and a condensate pool is provided and communicated in a cylinder block below the lower side of the gas recirculation passage. The engine according to claim 1, wherein a discharge port is formed between the condensed water reservoir and the outside. The gas recirculation passage is disposed so as to be inclined so that either the intake side or the exhaust side is downward, and a condensed water reservoir is formed at a lower portion of the passage connected to the lower side of the gas recirculation passage. The engine according to claim 1, wherein a discharge port is formed in a lower portion of the pool.

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