JP2020002797A - Intake system for multiple cylinder engine - Google Patents

Abstract

To actualize an intake passage layout which suppresses the occurrence of misfire due to condensed water generated from an intercooler and enables a compact figure without increasing the distribution resistance of intake air.SOLUTION: An intake system for a multiple cylinder engine includes a supercharger 32 connected to an intake pipe 30 of an engine 1, an intercooler 37 connected to the downstream side of the intake pipe beyond the supercharger, a surge tank 38 arranged on the downstream side thereof beyond the intercooler, and an external EGR passage 56 for introducing EGR gas to the upstream side of the intake pipe beyond the intercooler. The intercooler is arranged in parallel to the surge tank, and connected thereto via a connection intake pipe 30b. The connection intake pipe is planarly U-shaped and connected to the one-end side of the surge tank in a cylinder row. The bottom face of the intercooler inclines to be lower at its downstream side than at its upstream side. The bottom face of the connection intake pipe is short or the same in height than or as the lowest portion of the bottom face of the intercooler.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an intake device for a multi-cylinder engine.

  Patent Literature 1 below describes a configuration in which an intercooler is arranged above a mechanical supercharger arranged on a side of an engine body and close to the outside of an intake manifold. The inlet and outlet of this intercooler are arranged in the vertical direction of the engine body, and this outlet is connected to one end of the surge tank in the longitudinal direction.

JP 09-242548 A

  The intercooler described in Patent Literature 1 is a so-called vertical type intercooler having an inlet and an outlet arranged in the vertical direction of an engine body. For example, an EGR (exhaust gas recirculation) is provided upstream of the intercooler. In the case of the configuration in which gas is introduced, condensed water generated by the intercooler stays inside the intercooler.

  At this time, when the engine is in an accelerated state, there is a problem that the condensed water that has stayed at one time flows into the intake manifold, and a misfire occurs in some cylinders.

  SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and in a configuration in which EGR gas is introduced into an intake pipe, in particular, it is possible to suppress the occurrence of misfire due to condensed water generated by an intercooler, and to increase It is an object of the present invention to realize an intake path layout that can be realized.

  In order to achieve the above object, the present invention provides a flat U-shaped connection intake pipe at a portion of a side of a surge tank in an intake pipe of an engine which is connected to one end of a cylinder row. Is configured such that the bottom surface is lowered on the downstream side.

  Specifically, the present invention is directed to an intake device for a multi-cylinder engine, and has taken the following solutions.

  That is, the first invention provides a supercharger connected to an intake pipe provided in a multi-cylinder engine, an intercooler connected to a downstream side of the supercharger in the intake pipe, and a downstream side of the intercooler. This is an intake device for a multi-cylinder engine including a surge tank provided therein and an EGR passage for introducing EGR gas upstream of an intercooler in an intake pipe. The intercooler is arranged in parallel with the surge tank and is connected by a connection intake pipe. The connection intake pipe is formed in a U-shape in plan view, and is connected to one end of the cylinder row of the surge tank. The bottom surface of the intercooler is inclined so that the downstream side is lower than the upstream side. The bottom surface of the connecting intake pipe is lower or the same as the lowest part of the bottom surface of the intercooler.

  According to this, the bottom surface of the intercooler arranged in parallel with the surge tank and connected by the connection intake pipe is inclined so that the downstream side is lower than the upstream side, and is formed in a plane U-shape. The bottom surface of the connection intake pipe connected to one end of the cylinder row of the tank is lower than or equal to the lowest portion of the bottom surface of the intercooler. With this configuration, in particular, stagnation of condensed water by the EGR gas in the intake pipe is reduced. For this reason, since the accumulated condensed water does not flow into the intake manifold at a stretch, it is possible to suppress the occurrence of misfire in some of the cylinders. In addition, since the surge tank and the intercooler are arranged in parallel without increasing the intake air flow resistance, the size can be reduced.

  In a second aspect based on the first aspect, an intake adjustment valve is connected to an upstream side of the intercooler in the intake pipe, and the intake adjustment valve is disposed close to the surge tank in plan view. You may.

  According to this, the compactness can be further improved by the parallel arrangement of the intercooler and the surge tank disposed in proximity to the intake adjustment valve.

  In a third aspect based on the second aspect, the upstream portion of the intake adjustment valve in the intake pipe is disposed above the engine body, and the upstream portion of the intake adjustment valve is inclined downward from the middle thereof. It may be arranged so that it becomes.

  According to this, it is possible to effectively suppress the accumulation of the condensed water by the downwardly inclined supercharging path including the intake pipe of the supercharger.

  In a fourth aspect based on the first to third aspects, the intercooler may be a water-cooled intercooler using a liquid refrigerant.

  According to this, since the water-cooled intercooler easily generates condensed water as compared with the air-cooled intercooler, the effect of the present invention is remarkable.

  ADVANTAGE OF THE INVENTION According to this invention, while suppressing generation | occurrence | production of misfire by condensed water produced by an intercooler, it is possible to realize an intake path layout that can be made compact without increasing intake air flow resistance.

FIG. 1 is a schematic configuration diagram showing an engine according to an embodiment of the present invention. FIG. 2 is a plan view including an intake path in the engine according to the embodiment of the present invention. FIG. 3 is a left side view including an intake path in the engine according to the embodiment of the present invention. FIG. 4 is an upper left front perspective view including an intake path in the engine according to the embodiment of the present invention. FIG. 5 is an upper left rear perspective view showing the surge tank and the intake passage in the engine according to the embodiment of the present invention. FIG. 6 is a sectional perspective view taken along line VI-VI of FIG. FIG. 7 is a sectional view taken along line VII-VII in FIG. FIG. 8 is a sectional view taken along line VIII-VIII in FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the invention, its applications, or its uses.

(One embodiment)
An embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows a multi-cylinder engine with a supercharger according to the present embodiment, and here schematically shows the configuration of an engine with a supercharger (hereinafter simply referred to as “engine”) 1.

  The engine 1 is, for example, a four-stroke internal combustion engine mounted on an automobile, and includes a turbocharger 32 as shown in FIG. Although the fuel of the engine 1 is not particularly limited, it is light oil in the present embodiment.

  Although not shown in detail, the engine 1 includes, for example, four cylinders (cylinders) 11 arranged in a row, and the four cylinders 11 extend in the front-rear direction (vehicle length direction) of the vehicle. It is configured as a so-called in-line four-cylinder vertical engine that is mounted side by side. Thus, in this configuration example, the longitudinal direction of the engine, which is the direction in which the four cylinders 11 are arranged (cylinder row direction), substantially matches the vehicle length direction, and the engine width direction substantially matches the vehicle width direction. ing. Note that the engine 1 is not limited to an in-line four-cylinder vertically installed engine, but the present invention is also applicable to an in-line multi-cylinder vertically or horizontally installed engine.

  Further, in the in-line multi-cylinder engine, the direction of the cylinder rows coincides with the direction of the center axis of the crankshaft 15 (engine output axis direction) as the engine output shaft. In the following description, these directions may be collectively referred to as a cylinder row direction (or a vehicle length direction).

  Hereinafter, unless otherwise specified, the front side refers to the front side (engine front side) in the vehicle front-rear direction, the rear side refers to the rear side (engine rear side) in the vehicle front-rear direction, and the left side refers to the vehicle width direction. The left side refers to the front, and the right side refers to the right side in the vehicle width direction.

  In the following description, the upper side refers to the upper side in the vehicle height direction when the engine 1 is mounted on the vehicle (hereinafter, also referred to as the “vehicle mounted state”), and the lower side refers to the vehicle height direction when the vehicle is mounted. Point to the lower side.

(Schematic configuration of engine)
In the present embodiment, the engine 1 includes an engine body 10 having four cylinders 11, and an intake path 30 including an intake pipe arranged on the left side of the engine body 10 and communicating with each cylinder 11 via an intake port 18. , An exhaust passage 50 disposed on the right side of the engine body 10 and communicating with each cylinder 11 via an exhaust port 19.

  In the present configuration example, the intake path 30 is a unitized intake apparatus in which a plurality of passages for guiding fresh air and exhaust gas (hereinafter, referred to as intake) and devices such as the turbocharger 32 and the intercooler 37 are combined. Is composed.

  The engine body 10 is configured to burn the intake air supplied from the intake passage 30 and the fuel injected from the injector 6 in each cylinder 11 in a predetermined combustion order. Specifically, the engine main body 10 has a cylinder block 12 and a cylinder head 13 mounted on the cylinder block 12.

  The four cylinders 11 described above are formed inside the cylinder block 12. The four cylinders 11 are arranged along the center axis direction of the crankshaft 15 (cylinder row direction). FIG. 1 shows only one cylinder.

  A piston 14 is slidably inserted into each cylinder 11. Each piston 14 is connected to a crankshaft 15 via a connecting rod 141. Each piston 14 defines a combustion chamber 16 together with the cylinder 11 and the cylinder head 13. The “combustion chamber” here is not limited to the meaning of only the space formed when the piston 14 reaches the compression top dead center. The term "combustion chamber" is used in a broad sense.

  For example, two intake ports 18 are formed per cylinder 11 in the cylinder head 13. FIG. 1 shows only one intake port 18. The two intake ports 18 are adjacent to each other in the cylinder row direction and communicate with the corresponding cylinders 11.

  Each of the two intake ports 18 is provided with an intake valve 21. The intake valve 21 opens and closes between the combustion chamber 16 and each intake port 18. The intake valve 21 is opened and closed at a predetermined timing by an intake valve operating mechanism 23.

  In the cylinder head 13, for example, two exhaust ports 19 are formed for one cylinder 11. FIG. 1 shows only one exhaust port 19. The two exhaust ports 19 are adjacent to each other in the cylinder row direction and communicate with the corresponding cylinders 11.

  Each of the two exhaust ports 19 is provided with an exhaust valve 22. The exhaust valve 22 opens and closes between the combustion chamber 16 and each exhaust port 19. The exhaust valve 22 is opened and closed at a predetermined timing by an exhaust valve mechanism 24.

  The injector 6 is attached to the cylinder head 13 for each cylinder 11. In the present configuration example, each injector 6 is, for example, a multi-injection type fuel injection valve, and is configured to directly inject fuel into each combustion chamber 16.

  In addition, the intake path 30 according to the present embodiment is connected to one side surface (specifically, a left side surface) of the engine main body 10 and communicates with the intake port 18 of each cylinder 11. That is, the intake passage 30 is a passage through which the intake air introduced into the combustion chamber 16 flows, and is therefore connected to the combustion chamber 16 via each intake port 18.

  Between the air cleaner 31 and the surge tank 38 in the intake path 30, from the upstream side, a compressor wheel (hereinafter, referred to as a compressor) 32a of a turbocharger 32, an intake adjustment valve 33 which is normally fully opened, and an intercooler 37 are sequentially arranged. The intake adjustment valve 33 is configured to adjust the degree of recirculation of burned gas (EGR gas) introduced into the combustion chamber 16 by adjusting the opening thereof.

  The intercooler 37 houses a core (not shown) configured to exchange heat with intake air that has passed through the turbocharger 32, and is configured to cool intake air compressed in the turbocharger 32. Have been. The intercooler 37 may be either a water-cooled type or an air-cooled type, and here is a water-cooled type using a liquid refrigerant from the viewpoint of cooling efficiency.

  On the other hand, as shown in FIG. 1, the exhaust passage 50 is connected to the other side surface (specifically, the right side surface) of the engine body 10 and communicates with the exhaust port 19 of each cylinder 11. The exhaust passage 50 is a passage through which the exhaust gas discharged from the combustion chamber 16 flows. Although not shown in detail, the upstream portion of the exhaust passage 50 constitutes an independent passage branched for each cylinder 11. The upstream ends of these independent passages are connected to the exhaust port 19 of each cylinder 11.

  In the exhaust passage 50, the above-described turbine 32b of the turbocharger 32, a diesel oxidation catalyst (DOC) 51 for oxidizing nitrogen monoxide (NO), carbon monoxide (CO), hydrocarbon (HC), and the like and fine particles are captured. An exhaust gas purification system having a diesel particulate filter (DPF) 52 for collecting the exhaust gas and an exhaust shutter valve 53 for adjusting the flow rate of exhaust gas are provided. Here, a waste gate valve 54 that bypasses exhaust gas to the turbine 32 b of the turbocharger 32 is provided in the exhaust passage 50. As the turbocharger 32, a variable capacity turbocharger can be used, and depending on the specification, a configuration without the waste gate valve 54 can be adopted.

A urea SCR (Selective Catalytic Reduction) for purifying nitrogen oxides (NO _x ) and a slip catalyst for oxidizing excess ammonia (NH ₃ ) from the urea SCR are appropriately provided downstream of the DPF 52. Is also good. The urea SCR (Selective Catalytic Reduction) is provided with a urea tank.

  An internal EGR (high-pressure EGR) passage 55 that introduces exhaust gas from the exhaust passage 50 from a vicinity of an exhaust manifold (not shown) to a downstream portion of the intercooler 37 in the intake passage 30, An external EGR (low pressure EGR) passage 56 for introducing exhaust gas from the downstream side of the DPF 52 in the passage 50 to the upstream side of the compressor 32a of the turbocharger 32 is provided. Each of the internal EGR passage 55 and the external EGR passage 56 is a passage for returning a part of the burned gas to the intake passage 30.

  The external EGR passage 56 is provided with, for example, a water-cooled low-pressure EGR cooler 57. The low pressure EGR cooler 57 cools the burned gas. The recirculation amount of the burned gas flowing through the external EGR passage 56 is adjusted by an external EGR valve 58 disposed between the low-pressure EGR cooler 57 and a connection of the external EGR passage with the intake path 30.

  On the other hand, the recirculation amount of the burned gas flowing through the internal EGR passage 55 is adjusted by the internal EGR valve 59 provided in the internal EGR passage 55.

(Configuration of intake path)
Hereinafter, a configuration of a main part of the intake path 30 will be described in detail.

  Each part of the intake pipe constituting the intake path 30 is disposed along the left side of the engine body 10, specifically, along the left side of the cylinder head 13 and the cylinder block 12. The portion of the intake passage 30 from the compressor 32a of the turbocharger 32 to the intercooler 37 is arranged from the right side to the left side of the engine body 10 so as to pass above it.

  2, 3, and 4 respectively show a plan view, a left side view, and a front perspective view of the left side of the engine 1 according to the present embodiment. As shown in FIGS. 2 to 4, a portion of the intake passage 30 from the turbocharger 32 to the intake adjustment valve 33, that is, a first passage 30 a which is an upstream portion of the intake adjustment valve 33 is disposed above the engine body 10. It is arranged so that it is inclined downward from the middle.

  Further, the intercooler 37 is arranged in parallel with the surge tank 38, and is connected to the surge tank 38 by the connection intake pipe 30b. Note that the connection intake pipe 30b between the intercooler 37 and the surge tank 38 may be referred to as an introduction path 30b. The connection intake pipe 30b is formed in a U-shape in plan view, and is connected to the front side of the cylinder row of the surge tank 38. The bottom surface of the intercooler 37 is inclined so that the downstream side (front side) is lower than the upstream side (rear side). The bottom surface inside the connection intake pipe 30b is lower than or the same as the lowest part (downstream end) of the bottom inside the intercooler 37. That is, the bottom surface in the connection intake pipe 30b is arranged so as not to be higher than the bottom surface in the intercooler 37.

  Further, as shown in FIG. 2, the intake adjustment valve 33 connected to the upstream side of the intercooler 37 is disposed close to the surge tank 38 in plan view.

  As described above, the intercooler 37 is arranged in parallel with the surge tank 38 to form a so-called side entry type, and the bottom surface inside the connection intake pipe 30b is made lower than or the same as the inside bottom surface of the intercooler 37. By doing so, the condensed water due to the low-pressure EGR gas is less likely to stay, particularly in the intercooler 37 and the connection intake pipe 30b. In addition, the connection intake pipe 30b is smoothly bent in a plane U-shape, and the surge tank 38 and the intercooler 37 are arranged in parallel without increasing the intake air flow resistance. Is arranged close to the intake adjustment valve 33, so that the size of the engine 1 can be reduced.

(Structure of surge tank)
FIG. 5 illustrates the connection intake pipe 30b and the surge tank 38 according to the present embodiment, and FIGS. 6 to 8 illustrate cross-sectional configurations along lines VI-VI, VII-VII, and VIII-VIII in FIG. I have.

  As shown in FIG. 6, the surge tank 38 has an intake manifold 39 connected to an opening on the engine body side. Further, as shown in FIGS. 6 to 8, inside the surge tank 38, it is provided continuously inside the connection intake pipe (introduction path) 30 b and stands upright from the bottom of the surge tank 38. At the same time, a baffle wall portion 38a is provided which extends in the cylinder row direction and has a height gradually reduced. The baffle wall 38a is provided upright from the bottom of the surge tank 38 so as to be convex toward the engine body. Further, the surge tank 38 is formed to have a large width on the front side of the cylinder row into which intake air flows, and a large sectional volume. On the other hand, the surge tank 38 is formed so as to have a smaller width and a smaller sectional volume toward the rear end side of the cylinder row.

  The members constituting the surge tank 38 including the baffle wall 38a and the intake manifold 39 are not particularly limited. However, if a synthetic resin material having excellent heat resistance is used, the surge baffle wall 38a having a desired shape can be subjected to surge. It can be easily formed integrally with the tank 38.

  With this configuration, the baffle wall 38a is concave inside the surge tank 38, so that the flow resistance of the intake air accompanying the formation of the baffle wall 38a is reduced. Furthermore, since the downstream cross-sectional volume of the surge tank 38 is reduced, good distribution of condensed water can be ensured.

  INDUSTRIAL APPLICABILITY The present invention can suppress the occurrence of misfire due to condensed water from an intercooler, and can realize an intake path layout that enables compactness without increasing intake air flow resistance, and is useful as an intake device for a multi-cylinder engine. It is.

1 engine (supercharged engine)
10 Engine body 30 Intake path (intake pipe)
30a First passage 30b Connection intake pipe (introduction path)
31 air cleaner 32 turbocharger 32a compressor wheel 32b turbine wheel 33 intake control valve 37 intercooler 38 surge tank 38a baffle wall 39 intake manifold 50 exhaust passage 55 internal EGR passage 56 external EGR passage

Claims (4)

A supercharger connected to an intake pipe provided in a multi-cylinder engine,
An intercooler connected to a downstream side of the supercharger in the intake pipe;
A surge tank disposed downstream of the intercooler,
An EGR passage for introducing EGR gas upstream of the intercooler in the intake pipe;
The intercooler is arranged in parallel with the surge tank and connected by a connection intake pipe,
The connection intake pipe is formed in a U shape in a plan view, and is connected to one end side of a cylinder row of the surge tank,
The bottom surface of the intercooler is inclined such that the downstream side is lower than the upstream side,
An intake device for a multi-cylinder engine, wherein a bottom surface of the connection intake pipe is lower than or the same as a lowest portion of a bottom surface of the intercooler. The intake device for a multi-cylinder engine according to claim 1,
An intake adjustment valve is connected to an upstream side of the intercooler in the intake pipe,
The intake device for a multi-cylinder engine, wherein the intake adjustment valve is disposed close to the surge tank in a plan view. The intake device for a multi-cylinder engine according to claim 2,
An upstream portion of the intake adjustment valve in the intake pipe is disposed above an engine body,
An intake device for a multi-cylinder engine, wherein an upstream portion of the intake adjustment valve is disposed so as to be inclined downward from the middle thereof. The intake device for a multi-cylinder engine according to any one of claims 1 to 3,
An intake device for a multi-cylinder engine, wherein the intercooler is a water-cooled intercooler using a liquid refrigerant.

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