Intake system for internal combustion engine

Abstract

To provide an intake device of an internal combustion engine capable of preventing an opening part for introducing predetermined fluid to a surge tank from being frozen by intake air flowing in the surge tank.SOLUTION: In an intake device of an engine 1, a surge tank 8 has a cover member 43 that covers an opening part 42a from a right side wall 31 side, and the cover member 43 is connected to a portion of a left side wall 32 located outside on both sides in a cylinder row direction L1 with respect to a ceiling wall 34 and the opening part 42a, and bulges from the left side wall 32 toward the right side wall 31 side. The lower end part of the cover member 43 is located below the opening part 42a, and a communication port 44 is provided in the lower end part of the cover member 43. The communication port 44 communicates between an internal space 43a of the cover member 43 surrounded by the cover member 43, the ceiling wall 34 and the left side wall 32, and an internal space 8a of the surge tank 8.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an intake system for an internal combustion engine. [Background technology]

[0002] Conventionally, there has been known a recirculated exhaust gas introduction structure for an intake manifold that recirculates exhaust gas such as EGR (Exhaust Gas Recirculation) gas to an engine via the intake manifold (see Patent Document 1).

[0003] This intake manifold recirculated exhaust gas introduction structure has an exhaust gas introduction pipe that introduces the exhaust recirculated gas flowing through the EGR passage of the cylinder head into the surge tank of the intake manifold.

[0004] One end of the exhaust gas introduction pipe is inserted into the EGR passage of the cylinder head, and the other end, which has a discharge port for discharging the EGR gas, is inserted into the surge tank.

[0005] As a result, the EGR gas flowing through the EGR passage is introduced into the exhaust gas introduction pipe, and then directly into the inside of the surge tank from the discharge port. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2011-111981 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the conventional intake manifold recirculated exhaust gas introduction structure, the other end having the discharge port for discharging the EGR gas is inserted inside the surge tank, so when the internal combustion engine is operated in a cold region or in winter, the discharge port is exposed to the cold air flowing through the surge tank when cold air is drawn into the intake manifold, which may cause the discharge port to freeze due to the cold air.

[0008] The present invention has been made in light of the above-mentioned circumstances, and has as its object to provide an intake device for an internal combustion engine that can prevent the opening through which a specified fluid is introduced into the surge tank from being frozen by the intake air flowing through the surge tank. [Means for solving the problem]

[0009] The present invention relates to a surge tank and a plurality of branch pipes arranged in a direction in which cylinders of an internal combustion engine are aligned and connected to the surge tank, the surge tank having an upstream side wall having an air intake port for taking in intake air, a downstream side wall facing the upstream side wall in the flow direction of the intake air and having a plurality of air outlets for taking out the intake air, a bottom wall connecting a lower end of the upstream side wall to a lower end of the downstream side wall, and a ceiling wall connecting an upper end of the upstream side wall to an upper end of the downstream side wall, the branch pipes being connected to the downstream side wall so that the intake air is introduced from each of the plurality of air outlets, the surge tank having a piping section to which piping through which a predetermined fluid flows is connected, the piping section being configured to connect the intake air from the air intake port toward the plurality of air outlets, An intake device for an internal combustion engine has an opening formed in an upper part of the downstream sidewall so as to face the direction of air flow, and introduces fluid into the inside of the surge tank through the opening, wherein the surge tank has a cover member covering the opening from the upstream sidewall side, the cover member is connected to a portion of the downstream sidewall located on both sides outwardly of the ceiling wall and the opening in the direction of cylinder arrangement, and bulges from the downstream sidewall toward the upstream sidewall, the lower end of the cover member is located below the opening, and a communication portion is provided at the lower end of the cover member, and the communication portion communicates between the internal space of the cover member surrounded by the cover member, the ceiling wall, and the downstream sidewall and the internal space of the surge tank. Effect of the Invention

[0010] As described above, according to the present invention, the opening through which the predetermined fluid is introduced into the surge tank can be prevented from being frozen by the intake air flowing through the surge tank. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a plan view of an internal combustion engine equipped with an intake device according to a first embodiment of the present invention. [Diagram 2]FIG. 2 is a plan view of an intake system and blow-by gas piping for an internal combustion engine according to a first embodiment of the present invention. [Diagram 3] FIG. 3 is a front view of an intake device for an internal combustion engine according to a first embodiment of the present invention. [Figure 4] 4 is a cross-sectional view taken along the line IV-IV in FIG. [Diagram 5] 5 is a cross-sectional view taken along the line VV in FIG. 2. FIG. [Figure 6] 6 is a cross-sectional view taken along the line VI-VI in FIG. [Figure 7] FIG. 7 is a cross-sectional view taken along the line VII-VII of FIG. [Figure 8] FIG. 8 is a diagram showing an intake device of an internal combustion engine according to a second embodiment of the present invention, which corresponds to a cross section taken along the arrows VI-VI in FIG. 3, and shows an example in which the positions of the cover member and the openings of the piping section are different from those of the first embodiment. [Figure 9] FIG. 9 is a diagram showing an intake device of an internal combustion engine according to a second embodiment of the present invention, which corresponds to a cross section taken along the VII-VII direction in FIG. 2 and shows an example in which the positions of the cover member and the openings of the piping section are different from those of the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] An intake device for an internal combustion engine according to one embodiment of the present invention has a surge tank, and a plurality of branch pipes arranged in a direction in which cylinders of the internal combustion engine are aligned and connected to the surge tank. The surge tank has an upstream sidewall having an air intake port for taking in intake air, a downstream sidewall facing the upstream sidewall in the flow direction of the intake air and having a plurality of air outlets for taking out the intake air, a bottom wall connecting a lower end of the upstream sidewall with a lower end of the downstream sidewall, and a ceiling wall connecting an upper end of the upstream sidewall with an upper end of the downstream sidewall. The branch pipes are connected to the downstream sidewall so that the intake air is introduced from each of the plurality of air outlets. The surge tank has a piping section to which piping through which a predetermined fluid flows is connected, and the piping section has an air outlet. An intake device for an internal combustion engine has an opening formed in an upper part of a downstream sidewall so as to face the flow direction of intake air from an air intake to a plurality of air outlets, and introduces fluid into the interior of a surge tank through the opening, wherein the surge tank has a cover member covering the opening from the upstream sidewall, the cover member being connected to portions of the downstream sidewall located outward on both sides in the direction of cylinder arrangement relative to the ceiling wall and the opening, and bulging from the downstream sidewall towards the upstream sidewall, the lower end of the cover member being located below the opening, and a communication portion being provided at the lower end of the cover member, the communication portion communicating between the internal space of the cover member surrounded by the cover member, the ceiling wall and the downstream sidewall and the internal space of the surge tank.

[0013] As a result, the intake system for an internal combustion engine according to one embodiment of the present invention can prevent the opening through which a predetermined fluid is introduced into the surge tank from being frozen by the intake air flowing through the surge tank. EXAMPLES

[0014] An intake device for an internal combustion engine according to a first embodiment of the present invention will now be described with reference to the drawings.

[0015] 1 to 6 are diagrams showing an intake device for an internal combustion engine according to a first embodiment of the present invention. In Figures 1 to 6, the up, down, front, rear, left and right directions are based on the internal combustion engine mounted on the vehicle, and the front-to-rear direction of the vehicle (straight forward direction) is defined as the front-to-rear direction, the left-to-right direction of the vehicle (vehicle width direction) is defined as the left-to-right direction, and the up-to-down direction of the vehicle (vehicle height direction) is defined as the up-to-down direction.

[0016] First, the configuration will be described. In Fig. 1, engine 1 as an internal combustion engine mounted on a vehicle includes a cylinder block 2. Cylinder block 2 includes three cylinders 2A arranged in the front-rear direction and a crankshaft (not shown), which also extends in the front-rear direction. Engine 1 in this embodiment is a front-engine, rear-wheel drive (FR) type engine mounted vertically.

[0017] The engine 1 is not limited to an in-line three-cylinder engine, but may be, for example, a V-type engine, and the number of cylinders is not limited to three.

[0018] The engine 1 is installed under a floor panel of a vehicle (not shown). The cylinder block 2 of this embodiment is installed so that the center lines of the multiple cylinders 2A are inclined with respect to the vertical direction (up-down direction).

[0019] A cylinder head 3 is provided diagonally above the cylinder block 2. The cylinder head 3 has an intake port, an exhaust port, an intake valve that opens and closes the intake port, an exhaust valve that opens and closes the exhaust port, etc. (not shown). Note that only one intake port 3P is shown in FIG. 4.

[0020] A plurality of intake ports including the intake port 3P open to an intake side wall 3a of the cylinder head 3, and the cylinder head 3 is installed so that the intake side wall 3a faces upward.

[0021] A cylinder head cover 4 is provided diagonally above the cylinder head 3. A blow-by gas chamber (not shown) is formed inside the cylinder head cover 4, into which blow-by gas generated in the engine 1 is introduced.

[0022] Blow-by gas refers to incompletely burned or unburned gas that flows from the combustion chamber into the crankcase 2K of the cylinder block 2 through the gap between the wall surface of each cylinder 2A and the piston.

[0023] A blow-by gas passage (not shown) is formed in the cylinder block 2, which connects the inside of the crankcase 2K with the blow-by gas chamber of the cylinder head cover 4, and the blow-by gas accumulated in the crankcase 2K flows into the blow-by gas chamber through the blow-by gas passage.

[0024] An oil pan 5 is provided below the cylinder block 2, and oil for lubricating the engine 1 is stored in the oil pan 5.

[0025] The cylinder head cover 4 has a low portion 4A and a high portion 4B that bulges obliquely upward from the low portion 4A.

[0026] A blow-by gas outlet 4b is formed in the side wall 4a of the high-position portion 4B. The blow-by gas outlet 4b has a center line 4s facing the arrangement direction L1 of the cylinders 2A and opens at a position adjacent to the outer circumferential surface 4c of the low-position portion 4A of the cylinder head cover 4. Hereinafter, the arrangement direction L1 of the cylinders 2A will be referred to as the cylinder row direction L1.

[0027] An intake manifold 6 constituting an intake system is provided in the engine 1. The intake manifold 6 has a mounting flange 7 (see FIG. 2), and the mounting flange 7 is attached to the intake side wall 3a of the cylinder head 3.

[0028] The intake manifold 6 has a surge tank 8, which is disposed so as to face the mounting flange 7 in the horizontal direction (see FIG. 4).

[0029] The intake manifold 6 has a plurality of branch pipes 9A, 9B, and 9C. The branch pipes 9A, 9B, and 9C are provided between the mounting flange 7 and the surge tank 8, and are arranged side by side in the cylinder row direction L1. The arrangement direction of the branch pipes 9A, 9B, and 9C is the same as the cylinder row direction L1.

[0030] As shown in Fig. 3, when the branch pipes 9A, 9B, and 9C are viewed from the front in the cylinder row direction L1, the branch pipes 9A, 9B, and 9C are arranged side by side in the cylinder row direction L1. In Fig. 3, the branch pipes 9A and 9B are located behind the branch pipe 9C and cannot be seen from the front.

[0031] As shown in FIGS. 2 and 3, the surge tank 8 has a right side wall 31, a left side wall 32, a bottom wall 33, a ceiling wall , a front wall 35, and a rear wall .

[0032] As shown in FIGS. 5 and 6, a throttle body connecting portion 41 is provided on the right side wall 31, and the throttle body connecting portion 41 is provided offset toward the front side wall 35 from the center in the cylinder row direction L1.

[0033] The throttle body connecting portion 41 is connected to the throttle body 21 (see FIG. 1). A throttle valve (not shown) is housed in the throttle body 21, and the throttle valve adjusts the amount of intake air by adjusting the opening of an intake passage inside the throttle body 21.

[0034] An air cleaner (not shown) is provided upstream of the throttle body 21 , and intake air purified by the air cleaner is supplied to the throttle body 21 .

[0035] An air intake 31a is formed in the right side wall 31, and the air intake 31a is formed biased toward the front side wall 35 relative to the rear side wall 36 in the cylinder row direction L1.

[0036] An intake passage 41a is formed in the throttle body connecting portion 41, and intake air flowing through the intake passage of the throttle body 21 is taken from the intake passage 41a through the air intake port 31a by the intake negative pressure of the engine 1 and into the surge tank 8.

[0037] The left side wall 32 faces the right side wall 31 in the flow direction L2 of the intake air, and is provided downstream of the left side wall 32. In other words, the right side wall 31 is provided upstream of the left side wall 32.

[0038] Here, upstream and downstream refer to the upstream and downstream of the intake air flow direction. The intake air flow direction L2 is the direction in which air flows from the air intake 31a to the surge tank 8 toward the downstream side, and is perpendicular to the cylinder row direction L1 (left and right direction).

[0039] 6 and 7, three air outlets 32a, 32b, and 32c are formed in the left side wall 32, and the air outlets 32a, 32b, and 32c are arranged side by side in the cylinder row direction L1. In other words, the air outlets 32a, 32b, and 32c face each other in the cylinder row direction L1.

[0040] 6, the branch pipes 9A, 9B, and 9C and the air outlets 32a, 32b, and 32c are indicated by imaginary straight lines. In this embodiment, the right side wall 31 constitutes an upstream side wall, and the left side wall 32 constitutes a downstream side wall.

[0041] The bottom wall 33 connects the lower end of the right side wall 31 to the lower end of the left side wall 32. The ceiling wall 34 connects the upper end of the right side wall 31 to the upper end of the left side wall 32.

[0042] The front wall 35 connects the front end of the right wall 31, the front end of the left wall 32, the bottom wall 33 and the front end of the top wall 34.

[0043] The rear side wall 36 connects the rear end of the right side wall 31, the rear end of the left side wall 32, the rear end of the bottom wall 33, and the rear end of the ceiling wall 34.

[0044] 5, the left side wall 32 is inclined downward from the ceiling wall 34 so as to move away from the right side wall 31. That is, the rear side wall 36 is inclined downward from the ceiling wall 34 to the left.

[0045] Air outlets 32a, 32b, and 32c are provided at the lower part in the inclined direction of left side wall 32. Although only air outlet 32b is shown in Fig. 5, air outlets 32a and 32c are provided side by side in the front-to-rear direction of air outlet 32b at the lower part in the inclined direction of left side wall 32.

[0046] The branch pipes 9A, 9B, and 9C are connected to the left side wall 32 and take in intake air from air outlets 32a, 32b, and 32c, respectively.

[0047] The downstream ends of the branch pipes 9A, 9B, and 9C are connected to the mounting flange 7. As shown in Fig. 7, branch passages 9a, 9b, and 9c are formed inside the branch pipes 9A, 9B, and 9C, and the branch passages 9a, 9b, and 9c communicate with the internal space 8a of the surge tank 8 (see Fig. 5) and each intake port.

[0048] As shown in FIG. 6, air outlets 32b and 32c overlap with air intake 31a in cylinder row direction L1, and air outlet 32a is separated from air intake 31a in cylinder row direction L1.

[0049] As shown in FIG. 5, a piping section 42 is attached to the left side wall 32, and the piping section 42 protrudes from the left side wall 32 towards the cylinder head 3 (see FIG. 1).

[0050] The pipe section 42 has an opening 42a, and the opening 42a is provided at a downstream end of the pipe section 42. The opening 42a is formed in an upper part of the left side wall 32 and faces the direction L2 in which the intake air flows.

[0051] As shown in Fig. 6, the opening 42a is disposed away from the air intake 31a in the cylinder row direction L1. The opening 42a is disposed between the branch pipe 9B and the branch pipe 9C, i.e., above the partition wall 9m that separates the branch pipe 9B and the branch pipe 9C (see Fig. 7).

[0052] 1, the blow-by gas outlet 4b and the piping section 42 are connected by a blow-by gas piping 10. That is, the blow-by gas piping 10 is connected to the cylinder head cover 4 and the surge tank 8.

[0053] Specifically, as shown in FIG. 1, a PCV (Positive Crankcase Ventilation) valve 11 is attached to the blow-by gas outlet 4b, the upstream end of the blow-by gas piping 10 is connected to the PCV valve 11, and the downstream end of the blow-by gas piping 10 is connected to the piping section 42.

[0054] As an example, the PCV valve 11 operates in response to the pressure difference between the blow-by gas chamber of the cylinder head cover 4 and the intake manifold 6 downstream of the blow-by gas chamber, and introduces the blow-by gas from the blow-by gas chamber into the surge tank 8 when the valve is opened.

[0055] The blow-by gas in the blow-by gas chamber is introduced into the surge tank 8 through the opening 42a from the blow-by gas piping 10. The blow-by gas introduced into the surge tank 8 is introduced into the combustion chamber of the cylinder 2A through the branch pipes 9A, 9B, and 9C and the intake port, and is burned in the combustion chamber. The blow-by gas piping 10 of this embodiment constitutes a piping, and the blow-by gas constitutes a predetermined fluid.

[0056] As shown in FIGS. 1 and 2, the blow-by gas piping 10 has an upstream pipe section 10A, an intermediate pipe section 10B, and a downstream pipe section 10C.

[0057] The upstream pipe section 10A curves from the blow-by gas outlet 4b along the outer peripheral surface 4c of the lower part 4A of the cylinder head cover 4, passes between the delivery pipe 12 and the cylinder head 3, and extends to between the upstream ends of the branch pipes 9B and 9C.

[0058] The blow-by gas piping 10 is covered with a protector 13, and the blow-by gas piping 10 of this embodiment includes the protector 13. Hereinafter, the blow-by gas piping 10 and the protector 13 will be described as the blow-by gas piping 10.

[0059] The intermediate pipe portion 10B is disposed between the branch pipes 9B and 9C such that both sides of the intermediate pipe portion 10B are sandwiched between the branch pipes 9B and 9C. The downstream pipe portion 10C extends from the intermediate pipe portion 10B to the surge tank 8.

[0060] A delivery pipe 12 is attached to the cylinder head cover 4. The delivery pipe 12 supplies fuel stored in a fuel tank (not shown) to an injector (not shown) installed in the cylinder 2A.

[0061] 5 to 7, the surge tank 8 is provided with a cover member 43, which covers the opening 42a from the side of the right side wall 31. That is, the cover member 43 covers the opening 42a from the upstream side.

[0062] The cover member 43 has a front wall portion 43A, a rear wall portion 43B, inclined wall portions 43C and 43D, and a tip wall portion 43E.

[0063] The front wall portion 43A has an upper end connected to the ceiling wall 34 and a left end connected to a portion of the left side wall 32 on the front wall 35 side relative to the opening 42a, and protrudes from that portion toward the right side wall 31.

[0064] The rear wall portion 43B has an upper end connected to the ceiling wall 34 and a left end connected to a portion of the left side wall 32 on the rear wall 36 side relative to the opening 42a, and protrudes from that portion toward the right side wall 31.

[0065] The inclined wall portion 43C inclines toward the rear wall 36 as it moves from the right end of the front wall portion 43A toward the right side wall 31, and the inclined wall portion 43D inclines toward the front wall 35 as it moves from the right end of the front wall portion 43A toward the right side wall 31.

[0066] In other words, the inclined wall portions 43C and 43D are inclined outward on both sides in the cylinder row direction L1 from the tip wall portion 43E that constitutes the tip portion in the bulging direction protruding from the left side wall 32 to the right side wall 31 toward the left side wall 32.

[0067] The tip wall portion 43E is connected to the right ends of the inclined walls 43C and 43D in the inclination direction, and extends parallel to the cylinder row direction L1.

[0068] In this manner, the cover member 43 in this embodiment is connected to portions of the left side wall 32 that are located on both sides outward in the cylinder row direction L1 relative to the ceiling wall 34 and the opening 42a, and bulges out from the left side wall 32 toward the right side wall 31, covering the opening 42a from the right side wall 31 side.

[0069] 5 and 7, a communication port 44 is provided at the lower end of the cover member 43. As shown in Fig. 5, the communication port 44 communicates between an internal space 43a of the cover member 43 surrounded by the cover member 43, the ceiling wall 34, and the left side wall 32, and an internal space 8a of the surge tank 8.

[0070] The lower end of the cover member 43 where the communication port 44 is provided is located above the lower end 31m of the air intake 31a and below the upper end 31n of the air intake 31a. The communication port 44 of this embodiment constitutes a communication portion.

[0071] As shown in FIG. 6, the cover member 43 is disposed so as to be separated from the air intake 31a in the cylinder row direction L1, and does not overlap with the air intake 31a in the cylinder row direction L1.

[0072] Among the air outlets 32a, 32b, and 32c, an imaginary line connecting the air outlets 32b, 32c that face the air intake 31a in the flow direction L2 of the intake air and the air intake 31a in the flow direction L2 of the intake air is defined as a first imaginary line L3.

[0073] Further, an imaginary line that crosses a center portion C in the extending direction of the first imaginary line L3 in the cylinder row direction L1 is defined as a second imaginary line L4.

[0074] When the first imaginary straight line L3 and the second imaginary straight line L4 are set in this manner, the tip wall portion 43E of the cover member 43 is located closer to the right side wall 31 than the second imaginary straight line L4.

[0075] As shown in Fig. 2, piping parts 46 and 47 are provided on the ceiling wall of the surge tank 8. As shown in Fig. 6, the piping part 46 has an opening 46a that opens in the ceiling wall .

[0076] The piping section 46 is connected to a brake negative pressure booster (not shown) via a negative pressure pipe (not shown), and the negative pressure generated by the engine 1 is led from the surge tank 8 to the brake negative pressure booster via the opening 46a and the negative pressure pipe. The brake load booster reduces (assists) the operating force of the brake pedal (not shown) by using negative pressure.

[0077] The piping section 47 has an opening 47a opened in the left side wall 32. The piping section 47 is connected to a fuel tank (not shown) via a purge piping (not shown), and evaporated fuel purged from the fuel tank is introduced from the purge piping to the surge tank 8 via the opening 47a.

[0078] Next, the effects of the intake system of the engine 1 according to this embodiment will be described. The intake manifold 6 of the engine 1 of this embodiment has a surge tank 8 and a plurality of branch pipes 9A, 9B, 9C that are arranged in line in the cylinder row direction L1 of the engine 1 and connected to the surge tank 8.

[0079] The surge tank 8 has a right side wall 31 having an air intake 31a for taking in intake air, a left side wall 32 facing the right side wall 31 in the direction L2 of intake air flow and having air outlets 32a, 32b, 32c for taking out the intake air, a bottom wall 33 connecting the lower end of the right side wall 31 to the lower end of the left side wall 32, and a ceiling wall 34 connecting the upper end of the right side wall 31 to the upper end of the left side wall 32.

[0080] The branch pipes 9A, 9B, and 9C are connected to the left side wall 32 so that intake air is introduced from air outlets 32a, 32b, and 32c, respectively, and the surge tank 8 has a piping section 42 to which a blow-by gas piping 10 through which blow-by gas flows is connected.

[0081] The piping section 42 has an opening 42a formed in the upper part of the left side wall 32 so as to face the flow direction L2 of the intake air from the air intake 31a toward the air outlets 32a, 32b, 32c, and blow-by gas is introduced into the internal space 8a of the surge tank 8 through the opening 42a.

[0082] The surge tank 8 has a cover member 43 that covers the opening 42a from the right side wall 31 side, and the cover member 43 is connected to a portion of the left side wall 32 that is located on both sides outward in the cylinder row direction L1 from the ceiling wall 34 and the opening 42a, and bulges from the left side wall 32 toward the right side wall 31.

[0083] The lower end of the cover member 43 is located below the opening 42a, and a communication port 44 is provided at the lower end of the cover member 43. The communication port 44 communicates between an internal space 43a of the cover member 43 surrounded by the cover member 43, the ceiling wall 34, and the left side wall 32, and an internal space 8a of the surge tank 8.

[0084] As a result, when the engine 1 is operated in a cold region or in winter, the cold intake air W (see FIG. 5) taken into the internal space 8a of the surge tank 8 from the air intake 31a is prevented from colliding with the cover member 43, and the opening 42a is prevented from being exposed to the cold intake air. As a result, the opening 42a is prevented from freezing.

[0085] In addition, by colliding the intake air W taken into the internal space 8a of the surge tank 8 from the air intake 31a with the cover member 43, the intake air W is dispersed in the cylinder row direction L1 as shown by intake air W1, W2 in Figure 6, and the dispersed intake air W1, W2 can be directed toward the air intakes 32a and 32b.

[0086] This makes it possible to prevent most of the intake air W taken in through the air intake 31a from being biasedly drawn into a specific branch pipe, thereby improving the distribution performance of the intake air W.

[0087] In addition, since the opening 42a is covered by the cover member 43, the opening 42a is not affected by the dynamic pressure of the intake air W taken into the internal space 8a of the surge tank 8 from the air intake 31a, and the pressure in the internal space 43a of the cover member 43 can be reduced.

[0088] In addition, the intake air W flowing through the internal space 8a of the surge tank 8 due to the negative pressure of the engine 1 has a lower pressure below the communication port 44 than the pressure upstream, so that the intake air W flowing through the internal space 8a of the surge tank 8 can promote the suction effect.

[0089] Therefore, a larger amount of blow-by gas B (see FIG. 5) can be sucked into the internal space 8a of the surge tank 8 from the opening 42a through the internal space 43a of the cover member 43 and the communication port 44, thereby improving the processing performance of the blow-by gas B.

[0090] In addition, since the suction effect can be promoted by the intake air W flowing through the internal space 8a of the surge tank 8, the negative pressure guided from the opening 46a through the negative pressure piping to the brake negative pressure booster can be increased, thereby improving the operability of the brake pedal.

[0091] In addition, the amount of evaporated fuel introduced from the purge pipe through the opening 47a into the internal space 8a of the surge tank 8 can be increased, improving the performance of treating evaporated fuel.

[0092] In addition, according to the intake device of the engine 1 of this embodiment, the cover member 43 has inclined wall portions 43C, 43D that incline outward on both sides in the cylinder row direction L1 as they move from the tip wall portion 43E, which is the tip portion in the bulging direction that protrudes from the left side wall 32 toward the right side wall 31, toward the left side wall 32.

[0093] This allows the intake air W1, W2 that collides with the cover member 43 to be effectively dispersed in the cylinder row direction L1 along the inclined wall portions 43C, 43D, and allows the intake air W1, W2 to be directed toward the air outlets 32a and 32b.

[0094] Therefore, it is possible to more effectively prevent most of the intake air W taken in through the air intake 31a from being unevenly drawn into a specific branch pipe, and the distribution performance of the intake air W can be more effectively improved.

[0095] Furthermore, according to the intake system of the engine 1 of this embodiment, the cover member 43 is disposed so as to be spaced apart from the air intake 31a in the cylinder row direction L1.

[0096] This prevents the cold intake air W taken into the internal space 8a of the surge tank 8 from the air intake 31a from concentrating on and colliding with the cover member 43, and more effectively prevents the opening 42a from freezing.

[0097] In addition, by colliding the intake air W taken into the internal space 8a of the surge tank 8 from the air intake 31a with the cover member 43, the intake air W can be dispersed into intake air W1 and intake air W2 and directed toward the air intakes 32a and 32b.

[0098] That is, the intake air W taken into the internal space 8a of the surge tank 8 from the air intake 31a can be distributed to the branch pipe 9A that is farther away from the air intake 31a in the cylinder row direction L1 than the branch pipe 9B.

[0099] In addition, since the branch pipe 9C overlaps with the air intake 31a in the cylinder row direction L1, the intake air W taken into the internal space 8a from the air intake 31a can be directed toward the air outlet 32c as shown by intake air W3 in Figure 6.

[0100] As a result, the intake air W taken into the internal space 8a of the surge tank 8 from the air intake 31a can be more effectively prevented from being biased toward a specific branch pipe, and the distribution performance of the intake air W can be more effectively improved.

[0101] In this way, the intake device of the engine 1 of this embodiment can efficiently distribute the intake air W taken into the internal space 8a of the surge tank 8 from the air intake 31a to the branch pipes 9A, 9B, and 9C as shown by intake air W1, W2, and W3, due to the positional relationship between the air intake 31a, the cover member 43, and the air outlets 32a, 32b, and 32c, thereby more effectively improving the distribution performance of the intake air W.

[0102] In addition, by distributing a portion of the intake air W to the branch pipes 9A, 9B by the cover member 43 as indicated by intake air W1, W2, the blow-by gas B sucked in from the internal space 43a of the cover member 43 through the communication port 44 can be distributed to the branch pipes 9A, 9B by the suction effect of the intake air W1, W2 flowing toward the branch pipes 9A, 9B.

[0103] This makes it possible to prevent most of the blow-by gas B from being unevenly sucked into a specific branch pipe, thereby improving the processing performance of the blow-by gas.

[0104] Furthermore, according to the intake device of the engine 1 of this embodiment, if an imaginary line connecting the air intake 31a and the air outlets 32a, 32b facing the air intake 31a in the direction L2 of the intake air flow is defined as a first imaginary line L3, and an imaginary line crossing the center C in the extension direction of the first imaginary line L3 in the cylinder row direction L1 is defined as a second imaginary line L4, the tip wall portion 43E of the cover member 43 is located on the right side wall 31 side of the second imaginary line L4.

[0105] This allows the intake air W taken into the internal space 8a of the surge tank 8 from the air intake 31a to collide with the cover member 43 upstream of the second imaginary straight line L4, and distributes the intake air to the air outlets 32a, 32b at an early stage. As a result, the distribution performance of the intake air W can be improved more effectively.

[0106] In addition, according to the intake device of the engine 1 of this embodiment, the left side wall 32 is inclined so as to move away from the right side wall 31 as it extends downward from the ceiling wall 34, and the air outlets 32a, 32b, and 32c are provided at the lower part of the left side wall 32 in the inclined direction.

[0107] This allows the intake air W taken in through the air intake 31a to be drawn into the branch pipes 9A, 9B, 9C through the air outlets 32a, 32b, 32c along the sloping left side wall 32, reducing the effects of pressure loss of the intake air W and allowing the intake air W to flow smoothly within the internal space 8a of the surge tank 8.

[0108] This makes it possible to prevent cold air from accumulating in the internal space 8a of the surge tank 8, and more effectively suppresses the opening 42a from freezing.

[0109] Furthermore, since air can flow smoothly in the internal space 8a of the surge tank 8, the effect of sucking the blow-by gas B from the internal space 43a of the cover member 43 by the intake air W can be promoted more effectively. EXAMPLES

[0110] 8 and 9 are diagrams showing an intake system for an internal combustion engine according to a second embodiment of the present invention, in which the same components as those in the first embodiment are given the same reference numerals and their explanation will be omitted.

[0111] 8, a piping section 51 to which the blow-by gas piping 10 is connected is attached to the left side wall 32, and the piping section 51 has an opening 51a. The opening 51a is disposed diagonally above and to the right of the central air outlet 32b, and overlaps with the air intake 31a in the cylinder row direction L1. That is, the opening 51a is located in the center of the cylinder row direction L1, and is disposed side by side with the air intake 31a in the flow direction L2 of the intake air.

[0112] 8 and 9, the surge tank 8 is provided with a cover member 52. The cover member 52 is disposed at the center in the cylinder row direction L1, and covers the opening 51a from the right side wall 31 side. The cover member 52 has a front wall portion 52A, a rear wall portion 52B, inclined wall portions 52C and 52D, and a tip wall portion 52E.

[0113] The front wall portion 52A has an upper end connected to the ceiling wall 34 and a left end connected to a portion of the left side wall 32 on the front wall 35 side of the opening 51a, and protrudes from that portion toward the right side wall 31.

[0114] The rear wall portion 52B has an upper end connected to the ceiling wall 34 and a left end connected to a portion of the left side wall 32 on the rear wall 36 side of the opening 51a, and protrudes from that portion toward the right side wall 31.

[0115] The inclined wall portion 52C inclines toward the rear wall 36 as it moves from the right end of the front wall portion 52A toward the right side wall 31, and the inclined wall portion 52D inclines toward the front wall 35 as it moves from the right end of the front wall portion 52A toward the right side wall 31.

[0116] In other words, the inclined wall portions 52C, 52D are inclined outward on both sides in the cylinder row direction L1 from the tip wall portion 52E of the tip portion in the bulging direction protruding from the left side wall 32 to the right side wall 31 toward the left side wall 32. The inclined wall portions 52C, 52D of the present embodiment form inclined portions.

[0117] The tip wall portion 52E is connected to the right ends of the inclined walls 52C and 52D in the inclination direction, and extends parallel to the cylinder row direction L1.

[0118] In this manner, the cover member 52 in this embodiment is connected to a portion of the left side wall 32 located on the outside on both sides of the ceiling wall 34 and the opening 51a in the arrangement direction of the branch pipes, and bulges from the left side wall 32 to the right side wall 31, covering the opening 51a from the right side wall 31 side.

[0119] A communication port 53 is provided at the lower end of the cover member 52. The communication port 53 communicates between an internal space 52a of the cover member 52, which is surrounded by the cover member 52, the ceiling wall 34, and the left side wall 32, and an internal space 8a of the surge tank 8. The communication port 53 in this embodiment constitutes a communication portion.

[0120] 8, the cover member 52 overlaps with the air intake 31a in the cylinder row direction L1. That is, the cover member 52 is arranged side by side with the air intake 31a in the flow direction L2 of the intake air.

[0121] Next, the effects of the intake system of the engine 1 according to this embodiment will be described. When the engine 1 is operated in a cold region or in winter, the cold intake air W (see FIG. 8) taken into the internal space 8a of the surge tank 8 from the air intake 31a is prevented from colliding with the cover member 52, and the opening 51a is prevented from being exposed to the cold intake air W. As a result, the opening 51a can be prevented from freezing.

[0122] In addition, by colliding the intake air W taken into the internal space 8a of the surge tank 8 from the air intake 31a with the cover member 52, the intake air W is dispersed in the cylinder row direction L1 as shown by intake air W4, W5, and the dispersed intake air W4, W5 can be directed toward the branch pipe 9A and the branch pipe 9C.

[0123] This makes it possible to prevent most of the intake air W taken in through the air intake 31a from being biasedly drawn into a specific branch pipe, thereby improving the distribution performance of the intake air W.

[0124] In addition, since the intake air W flowing through the internal space 8a of the surge tank 8 promotes the suction effect, more blow-by gas can be sucked into the internal space 8a of the surge tank 8 from the opening 51a through the internal space 52a of the cover member 52, thereby improving the processing performance of the blow-by gas.

[0125] In addition, since the suction effect can be promoted by the intake air W flowing through the internal space 8a of the surge tank 8, the negative pressure guided from the opening 46a through the negative pressure piping to the brake negative pressure booster can be increased, thereby improving the operability of the brake pedal.

[0126] In addition, the amount of evaporated fuel introduced from the purge pipe through the opening 47a into the internal space 8a of the surge tank 8 can be increased, improving the performance of treating evaporated fuel.

[0127] In addition, according to the intake device of the engine 1 of this embodiment, the cover member 52 has a tip portion in the bulging direction that protrudes from the left side wall 32 toward the right side wall 31, i.e., inclined wall portions 52C, 52D that incline outward on both sides in the cylinder row direction L1 as they approach the left side wall 32 from the tip wall portion 52E.

[0128] This allows the intake air W that collides with the cover member 52 to be effectively dispersed in the cylinder row direction L1 along the inclined wall portions 52C, 52D as shown by intake air W4, W5, and allows the intake air W4, W5 to be efficiently directed toward the branch pipes 9A and 9C.

[0129] Furthermore, according to the intake device of the engine 1 of this embodiment, the cover member 52 is disposed so as to overlap the air intake 31a in the cylinder row direction L1.

[0130] This allows the intake air W taken into the internal space 8a of the surge tank 8 from the air intake 31a to reliably collide with the cover member 52, and makes it possible to more effectively prevent the opening 51a from freezing.

[0131] In addition, by directly colliding the intake air W taken into the internal space 8a of the surge tank 8 from the air intake 31a with the cover member 52, the intake air W can be dispersed into intake air W4 and intake air W5 and directed toward the branch pipes 9A and 9C.

[0132] In addition, since the branch pipe 9B overlaps with the air intake 31a in the cylinder row direction L1, the intake air W taken into the internal space 8a from the air intake 31a can be directed to the branch pipe 9B as shown by intake air W6.

[0133] As a result, the intake air W taken into the internal space 8a of the surge tank 8 from the air intake 31a can be prevented from being biased toward a specific branch pipe, and the distribution performance of the intake air W can be improved more effectively.

[0134] In this way, the intake system of the engine 1 of this embodiment can distribute the intake air W taken into the internal space 8a of the surge tank 8 from the air intake 31a to the branch pipes 9A, 9B, and 9C as shown by intake air W4, W5, and W6, by virtue of the positional relationship between the air intake 31a, the cover member 52, and the air outlets 32a, 32b, and 32c, thereby more effectively improving the distribution performance of the intake air W.

[0135] The engine 1 of this embodiment is a three-cylinder engine, and the cover member 52 is disposed at the center in the cylinder row direction L1 and overlaps with the central branch pipe 9B in the intake air flow direction L2.

[0136] This allows the intake air W taken into the internal space 8a of the surge tank 8 from the air intake 31a to be efficiently distributed to the branch pipes 9A and 9C located on both sides of the branch pipe 9B in the cylinder row direction L1.

[0137] In addition, the intake air W4, W5 is dispersed to the branch pipes 9A, 9C by the cover member 52 and directed to the branch pipes 9A, 9C, and the intake air W taken in from the air intake 31a is directed to the branch pipe 9B through the bottom of the cover member 52, thereby promoting the suction effect of the intake air W including the intake air W4, W5, W6 flowing toward the branch pipes 9A, 9B, 9C.

[0138] This allows the blow-by gas sucked from the internal space 52a of the cover member 52 into the internal space 8a of the surge tank 8 to be effectively dispersed into the branch pipes 9A, 9B, and 9C.

[0139] This makes it possible to prevent most of the blow-by gas from being unevenly sucked into a specific branch pipe, thereby improving the processing performance of the blow-by gas.

[0140] Furthermore, according to the intake device of the engine 1 of this embodiment, if an imaginary line connecting the air intake 31a and the air outlet 32b opposite the air intake 31a in the direction L2 of the intake air flow is defined as a first imaginary line L5, and an imaginary line crossing the center C in the extension direction of the first imaginary line L5 in the cylinder row direction L1 is defined as a second imaginary line L6, the tip wall portion 52E of the cover member 52 is located on the right side wall 31 side of the second imaginary line L6.

[0141] This allows the intake air taken into the internal space 8a of the surge tank 8 from the air intake 31a to collide with the cover member 52 upstream of the air outlets 32a, 32b, and 32c, and distributes the intake air to the branch pipes 9A and 9C at an early stage. As a result, the distribution performance of the intake air W can be improved more effectively.

[0142] In addition, according to the intake device of the engine 1 of this embodiment, the left side wall 32 is inclined so as to move away from the right side wall 31 as it extends downward from the ceiling wall 34, and the air outlets 32a, 32b, and 32c are provided at the lower part of the left side wall 32 in the inclined direction.

[0143] This allows the intake air W taken in through the air intake 31a to be drawn into the branch pipes 9A, 9B, 9C through the air outlets 32a, 32b, 32c along the sloping left side wall 32, reducing the effect of pressure loss of the intake air W and allowing the intake air W to flow smoothly within the internal space 8a of the surge tank 8.

[0144] This prevents cold air from accumulating in the internal space 8a of the surge tank 8, and more effectively prevents the opening 51a from freezing. In addition, the air can flow smoothly, so that the suction effect of the intake air W can be more effectively promoted.

[0145] As a result, a larger amount of blow-by gas can be sucked into the internal space 8a of the surge tank 8 through the opening 51a and the internal space 52a of the cover member 52.

[0146] In this embodiment, the piping is constituted by the blow-by gas piping 10, but is not limited thereto and may be an EGR piping or the like.

[0147] In addition, the shape of the cover members 43, 52 may be a semicircular shape that bulges from the left side wall 32 toward the right side wall 31, a trapezoidal shape, or a triangular shape. Regardless of the shape, it is desirable to form an inclined wall portion that inclines outward on both sides in the cylinder row direction L1 from the tip of the bulging direction toward the left side wall 32.

[0148] In addition, in the present embodiment, a sloping portion may be formed on the lower portion of the tip wall portion 43E, 52E of the cover member 43, 52 to guide the intake air that collides with the cover member 43, 52 toward the air outlet. In this way, the intake air can be more effectively distributed to the air outlets 32a, 32b, 32c.

[0149] Although an embodiment of the invention has been disclosed, it will be apparent to one of ordinary skill in the art that modifications may be made therein without departing from the spirit and scope of the invention, and it is intended that all such modifications and equivalents be included in the following claims. [Explanation of symbols]

[0150] 1...engine (internal combustion engine), 2A...cylinder, 6...intake manifold (intake system), 8...surge tank, 8a...internal space (internal space of surge tank), 9A, 9B, 9C...branch pipe, 10...blow-by gas piping (piping), 31...right side wall (upstream side wall), 31a...air intake, 32...left side wall (downstream side wall), 32a, 32b, 32c...air outlet, 33...bottom wall, 34...ceiling wall, 42...piping section, 42a...opening portion, 43, 52...cover member, 43a, 52a...internal space (internal space of cover member), 43C, 43D, 52C, 52D...inclined wall portion (inclined portion), 43E, 52E...tip wall portion (tip portion in the bulging direction of the cover member), 44, 53...communication port (communication portion), C...center portion in the direction in which the first imaginary straight line extends, L1...cylinder row direction (direction in which the cylinders are arranged), L2...direction in which the intake air flows, L3, L5...first imaginary straight line, L4, L6...second imaginary straight line

Claims

1. a surge tank; and a plurality of branch pipes arranged in a direction in which the cylinders of the internal combustion engine are aligned and connected to the surge tank, The surge tank has an upstream sidewall having an air intake port for taking in intake air, a downstream sidewall facing the upstream sidewall in the flow direction of the intake air and having a plurality of air outlets for taking out the intake air, a bottom wall connecting a lower end of the upstream sidewall and a lower end of the downstream sidewall, and a ceiling wall connecting an upper end of the upstream sidewall and an upper end of the downstream sidewall, the branch pipe is connected to the downstream side wall so that intake air is introduced from each of the plurality of air outlets, The surge tank has a piping section to which a piping through which a predetermined fluid flows is connected, the piping portion has an opening formed in an upper portion of the downstream side wall so as to face a flow direction of intake air from the air intake toward the plurality of air outlets, and a fluid is introduced into the surge tank through the opening, The surge tank has a cover member that covers the opening from the upstream side wall side, the cover member is connected to a portion of the downstream side wall located on both sides of the ceiling wall and the opening in a direction in which the cylinders are aligned, and bulges from the downstream side wall toward the upstream side wall, A lower end of the cover member is located below the opening, and a communication portion is provided at the lower end of the cover member, An intake device for an internal combustion engine, characterized in that the communication portion communicates an internal space of the cover member, which is surrounded by the cover member, the ceiling wall, and the downstream side wall, with an internal space of the surge tank.

2. The intake device of an internal combustion engine as described in claim 1, characterized in that the cover member has a pair of inclined portions that incline outward on both sides in the direction of the arrangement of the cylinders as they extend from the tip end of the cover member in the expanding direction from the downstream side wall toward the upstream side wall toward the downstream side wall.

3. 3. The intake system for an internal combustion engine according to claim 1, wherein the cover member is disposed so as to be spaced apart from the air intake in the direction in which the cylinders are aligned.

4. 3. The intake system for an internal combustion engine according to claim 1, wherein the cover member is disposed so as to overlap the air intake in a direction in which the cylinders are aligned.

5. When a virtual line connecting an air outlet facing the air intake in the flow direction of the intake air and the air intake in the flow direction of the intake air is defined as a first virtual line, and a virtual line crossing a center portion of the first virtual line in the extending direction of the intake air and the arrangement direction of the cylinders is defined as a second virtual line, 5. The intake system for an internal combustion engine according to claim 2, wherein a tip end portion of the cover member in a protruding direction is located on the upstream side wall side of the second imaginary straight line.

6. The downstream side wall is inclined so as to move away from the upstream side wall as it extends downward from the ceiling wall, 6. The intake system for an internal combustion engine according to claim 1, wherein the plurality of air outlets are provided at a lower portion in a tilt direction of the downstream side wall.

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