Intake system for internal combustion engine

Abstract

Provided is an air intake device for an internal combustion engine including an air intake passage 80, an air intake passage pipe 6; and a throttle valve 75. The air intake passage pipe 6 is located downstream of a throttle body 7, is equipped with a dividing wall 81 for dividing the air intake passage pipe into a tumble flow path 80A and a main flow path 80B, and has a resonator 100 that is connected with the intake passage 80 via a connecting pipe 101. The air intake passage pipe 6 has: an intake air control valve 65 that is located downstream of the throttle valve 75 and that controls the ratio between the air intake flow rates of the tumble flow path 80A and the main flow path 80B; and a connecting hole 102 that is open to the connecting pipe 101. The connecting pipe 101 is equipped with an air volume adjustment valve 110 that opens and closes the interior of the air intake passage pipe 6, and thus enhances the flow of tumble flow and improves combustion efficiency.

Description

[Technical field]

[0001] The present invention relates to an intake system for an internal combustion engine in which an intake passage is divided into a main passage and a tumble passage, and a resonator is provided which communicates with the intake passage. [Background technology]

[0002] A structure for dividing an intake passage of an internal combustion engine into a main passage and a tumble passage by a partition and generating a tumble flow is disclosed in, for example, Patent Document 1. In the intake device of an internal combustion engine as shown in Patent Document 1, a resonator communicating with the intake passage is not provided, the amount of intake air stored in the intake port is small, and the opening of the throttle valve is narrowed when the internal combustion engine is operating in a low load region. Therefore, during the intake stroke from when the intake valve opens to when it closes, the volume of the intake port side increases with the descent of the piston, but the inflow of the amount of air from the opening of the throttle valve does not keep up with the increase in volume, so the inside of the intake port is suddenly put into a negative pressure state, the flow in the intake passage is weakened, and the flow of the tumble flow is reduced. This causes a problem. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. WO2018 / 16391 Summary of the Invention [Problem to be solved by the invention]

[0004] Therefore, the present invention aims to provide an intake device for an internal combustion engine that can reduce the reduction in flow in the intake passage, strengthen the tumble flow, improve combustion efficiency, even when the throttle valve is throttled in the low load range of the internal combustion engine, and further improve combustion efficiency by switching the flow of air from the resonator to the tumble passage. [Means for solving the problem]

[0005] The present invention has been made in consideration of the above problems, and provides an intake system for an internal combustion engine having an intake passage that introduces intake air into a combustion chamber, an intake passage pipe whose interior forms a part of the intake passage, a throttle body that introduces intake air into the intake passage pipe, and a throttle valve provided inside the throttle body to control an opening degree of the intake passage, the intake passage pipe is disposed downstream of a throttle body and includes a partition wall that divides the intake passage into a tumble passage and a main passage along a longitudinal direction that is an inflow direction of intake air, a resonator communicating with the intake passage via a communication pipe; the intake passage pipe has an intake control valve located downstream of the throttle valve for controlling the intake flow rate ratio between the tumble flow passage and the main flow passage, and a communication hole opening into the communication pipe, The intake system of an internal combustion engine is characterized in that the communication pipe includes an air amount adjustment valve that opens and closes the inside of the intake passage pipe.

[0006] According to the above-mentioned configuration, by providing a resonator located downstream of the throttle valve in the intake passage pipe and communicating with the intake passage pipe, even when the throttle valve is closed during operation in the low load range of the internal combustion engine, the intake air flows from the resonator into the intake passage downstream of the throttle valve, so that the flow of the intake air in the intake passage is not reduced, and the flow of the tumble flow is strengthened, thereby improving the combustion efficiency. Furthermore, the above-mentioned effect can be further enhanced by switching the flow of air from the resonator into the intake passage pipe by the air amount control valve as necessary.

[0007] In the above-mentioned configuration, the intake control valve and the air amount adjustment valve may be provided on a shaft member that serves as the same rotation shaft.

[0008] According to the above-described configuration, the intake control valve and the air amount adjustment valve are provided on the shaft member that serves as the same rotating shaft, and thus the number of parts can be reduced by sharing the shaft.

[0009] In the above configuration, the intake control valve and the air amount adjustment valve may have a structure in which when one of the valves opens, the other valve closes.

[0010] According to the above configuration, by opening the intake control valve and closing the air flow control valve between the resonator during stoichiometric operation, it is possible to prevent a deterioration in fuel efficiency due to increased pumping loss caused by air flowing in from the resonator, which has a large intake volume, while by closing the intake control valve and opening the air flow control valve between the resonator during lean combustion, it is possible to utilize the intake volume of the resonator to promote the formation of tumble flow and improve combustion efficiency.

[0011] In the above-described configuration, the communication hole may be located between the downstream end of the throttle body and the upstream end of the partition wall.

[0012] According to the above configuration, by locating the communication hole communicating with the resonator at a location away from the internal combustion engine, which is the heat generating part, even when a relatively hot airflow flows into the intake passage, the heat is not transferred to the communication pipe communicating with the resonator, making it less susceptible to the effects of exhaust heat from the internal combustion engine, and preventing a decrease in intake efficiency.

[0013] In the above-described configuration, the intake passage pipe may have a mounting portion to which one end of the communication pipe is attached, and the mounting portion and the intake passage pipe may be formed as an integral part.

[0014] According to the above-mentioned configuration, a fixing part for fixing the mounting portion to the intake passage pipe is not required, which prevents an increase in the number of parts and reduces the amount of processing work.

[0015] In the above configuration, a fuel injection valve that injects fuel toward the inside of the intake passage is provided. A notch extending from the upstream side to the downstream side in the intake air flow direction may be provided on an inner wall of the intake passage pipe, and the communication hole may be provided at a position overlapping with the notch.

[0016] According to the above-mentioned configuration, it is possible to prevent the injected fuel from accumulating in the communication hole and the notch. Effect of the Invention

[0017] According to the present invention, by providing a resonator located downstream of the throttle valve in the intake passage pipe and communicating with the intake passage pipe, even when the throttle valve is closed during operation in the low load range of the internal combustion engine, the intake air flows from the resonator into the intake passage downstream of the throttle valve, so that the flow of the intake air in the intake passage is not reduced, and the flow of the tumble flow is strengthened, thereby improving the combustion efficiency. Furthermore, the above effect can be further enhanced by switching the inflow of air into the resonator using an air amount control valve as necessary. [Brief description of the drawings]

[0018] [Figure 1] 1 is a right side view of a motorcycle equipped with a power unit equipped with an intake structure for an internal combustion engine according to a first embodiment of the present invention. [Diagram 2] 2 is a rear right side view of the motorcycle in FIG. 1 with the body cover removed. [Diagram 3] 3 is a side cross-sectional view of the power unit in FIG. 2 taken out and shown in substantially the same orientation as that shown in FIG. 2, the power unit being provided with the intake structure for an internal combustion engine according to the first embodiment. [Figure 4] FIG. 4 is an enlarged view of a main part of FIG. [Diagram 5] FIG. 2 is a schematic diagram showing the periphery of an intake pipe and a resonator. [Figure 6] 4 is a cross-sectional view of an inlet pipe and a communication pipe cut at a position where a communication hole passes through. FIG. [Figure 7] FIG. 2 is a vertical cross-sectional view of the resonator. [Figure 8] FIG. 5 is an enlarged view of a main part of FIG. [Figure 9] FIG. 9 is an enlarged sectional perspective view of a main part of FIG. 8. [Figure 10] FIG. 2 is a left side view showing the vicinity of the throttle body and the inlet pipe. [Figure 11]FIG. 4 is a perspective view showing the periphery of an attachment portion of the inlet pipe. [Figure 12] 1 is a view of the periphery of the communication hole as viewed from inside the inlet pipe. [Figure 13] FIG. 4 is a perspective view showing a valve stem and a cutout portion of the air amount regulating valve. [Figure 14] 4 is a vertical cross-sectional view of a communication pipe and an air amount adjustment valve, showing an open state of the air amount adjustment valve. FIG. [Figure 15] 4 is a vertical cross-sectional view of a communication pipe and an air amount adjustment valve, showing a closed state of the air amount adjustment valve. FIG. [Figure 16] FIG. 4 is a schematic diagram showing a state in which the tumble control valve is open and the air amount adjustment valve is closed. [Figure 17] FIG. 4 is a schematic diagram showing a state in which the tumble control valve is closed and the air amount adjustment valve is open. [Figure 18] FIG. 2 is a schematic diagram of an intake passage showing a region downstream of a throttle valve. [Figure 19] FIG. 17 is a diagram showing pressure fluctuations at the points shown in FIG. 16 in the cycle of an internal combustion engine. [Figure 20] 4 is a graph showing the influence of the presence or absence of a resonator on pumping loss and fuel efficiency of an internal combustion engine when the tumble control valve is in an open state. [Figure 21] 4 is a graph showing the influence of the presence or absence of a resonator on pumping loss and fuel efficiency of an internal combustion engine when the tumble control valve is in a closed state. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] An intake device for an internal combustion engine according to one embodiment of the present invention will be described with reference to Figs.

[0020] In the description of this specification and the claims, the directions of front, rear, left, right, up and down, etc., are based on the directions of the vehicle when the power unit equipped with the intake device of the internal combustion engine according to this embodiment is mounted on the vehicle. In this embodiment, the vehicle is a small vehicle, specifically a motorcycle. However, with regard to the intake passage 70 of the throttle body 7 and the intake passage 80, the upper side of the partition part 81, which serves as a partition wall dividing them along the intake flow direction F, is described as the "upper" side, and the lower side is described as the "lower" side. In addition, in the drawings, the arrow FR indicates the front of the vehicle, LH indicates the left side of the vehicle, RH indicates the right side of the vehicle, and UP indicates the upper side of the vehicle, respectively.

[0021] Fig. 1 shows a right side view of a motorcycle 1 equipped with a power unit 3 equipped with an intake device for an internal combustion engine according to an embodiment of the present invention. Fig. 2 shows a rear right side view of the motorcycle 1 in Fig. 1 with a body cover 10 removed.

[0022] The motorcycle 1 equipped with the internal combustion engine intake device 60 of this embodiment is a so-called scooter-type motorcycle, in which a front body 1A and a rear body 1B are connected via a low floor portion 1C, and a body frame 2 forming the skeleton of the body is generally composed of a down tube 21 and a main pipe 22 (see Figure 2).

[0023] That is, a down tube 21 extends downward from a head pipe 20 in the front part 1A of the vehicle body, bends horizontally at its lower end and extends rearward below the floor part 1C, and as shown in Figure 2, a pair of left and right main pipes 22 are connected at their rear ends via a connecting frame 23 arranged in the width direction of the vehicle. The main pipes 22 rise diagonally rearward from the connecting frame 23 forming an inclined part 22a, and then bend to gentler the inclination midway before extending rearward.

[0024] A storage box 11 and a fuel tank 12 are supported above the inclined portion 22a of the main pipe 22, and the storage box 11 and the fuel tank 12 are covered by a passenger seat 13 attached above them, and the lower part of the passenger seat 13, including the storage box 11 and the fuel tank 12, is covered by a vehicle body cover 10. Meanwhile, in the front body 1A, a handlebar 14 is provided above and journaled on the head pipe 20, and a front fork 15 extends below and journals a front wheel 16 at its lower end.

[0025] As shown in Figure 2, which shows the rear right side of the motorcycle 1 with the body cover 10 removed, a bracket 24 protrudes from near the lower end of the inclined portion 22a of the main pipe 22, and the power unit 3 is connected and supported to the bracket 24 via a link member 25 so as to be able to swing.

[0026] The front part of the power unit 3 is a single-cylinder, four-stroke cycle, air-cooled internal combustion engine (hereinafter simply referred to as the "internal combustion engine") 30, and a crankshaft 51 is arranged in the vehicle width direction and rotatably supported at the front part of a power unit case 50 constituting a crankcase portion 50a, and the cylinder axis C is inclined significantly forward to a state close to horizontal, and the end of a hanger arm 52 protruding forward from the lower end of the power unit case 50 is connected via a link member 25 attached to a bracket 24 of the main pipe 22 so as to be freely swingable up and down.

[0027] In the power unit 3, the cylinder block 31, cylinder head 32, and cylinder head cover 33 constituting the internal combustion engine 30 are fastened in a substantially horizontal manner to the front part of the power unit case 50 constituting the crankcase part 50a so as to be stacked in order, and a power transmission case part 55 equipped with a belt-type continuously variable transmission and the like extends integrally from the crankcase part 50a to the rear left side, and a rear axle 56 which is the output shaft of the power unit 3 is provided at the rear part, and the rear wheel 17 is attached. In other words, the power unit 3 is a so-called swing unit, and a rear cushion (not shown) is interposed between the power transmission case part 55 at the rear of the power unit 3 and the rear part of the main pipe 22.

[0028] 2, at the top of the power unit 3, an inlet pipe 6 serving as an intake passage pipe extends and curves rearward from the top of the cylinder head 32 of the internal combustion engine 30, which is tilted significantly forward, and a throttle body 7 connected to the inlet pipe 6 is located above the cylinder block 31, and an air cleaner device 86 connected to the throttle body 7 via a connecting tube 85 is disposed above the power transmission case 55. On the other hand, an exhaust pipe 38 extending downward from the bottom of the cylinder head 32 bends rearward, leans to the right, and extends rearward to be connected to a muffler 39 on the right side of the rear wheel 17.

[0029] Fig. 3 is a side cross-sectional view of the power unit 3 in Fig. 2, taken out and shown in substantially the same orientation as that shown in Fig. 2. The internal combustion engine 30 in the power unit 3 is shown in cross section of the left half of the cylinder block 31, cylinder head 32, and cylinder head cover 33, and the power unit case 50 is shown with the left case half 50L facing the mating surface 50b with the right case half (not shown) toward the front of the figure.

[0030] The power unit case 50 is formed by combining a left case half 50L that is split left and right and a right case half (not shown). The right case half forms the right half of the crankcase section 50a, and the front part of the left case half 50L forms the left half of the crankcase section 50a and extends rearward to form a power transmission case section 55 that houses a transmission device including a long belt-type continuously variable transmission (not shown) and a reduction gear mechanism 57 between the crankshaft 51 and the rear axle 56 of the rear wheel 17.

[0031] The reduction gear mechanism 57 is housed inside the right open surface 55R at the rear of the power transmission case portion 55, and is covered by a reduction gear case (not shown). The output shaft of the reduction gear mechanism 57 is the rear axle 56 of the rear wheel 17. Thus, the rotational power of the crankshaft 51 of the crankcase portion 50a of the internal combustion engine 30 is transmitted to the rear wheel 17 via the belt-type continuously variable transmission in the power transmission case portion 55 and the reduction gear mechanism 57.

[0032] A piston 34 that reciprocates within a cylinder bore 31a of the cylinder block 31 is connected to a crank pin 51a of a crankshaft 51 in a crankcase portion 50a by a connecting rod 35. A combustion chamber 36 is defined between a top surface 34a of the piston 34 that is slidably fitted within the cylinder bore 31a of the cylinder block 31 and a combustion chamber ceiling surface 32a of the cylinder head 32 that faces the top surface 34a.

[0033] The internal combustion engine 30 employs an SOHC type two-valve system, and a valve train 9 is provided in a cylinder head 32. A cylinder head cover 33 is placed over the cylinder head 32 so as to cover the valve train 9.

[0034] To transmit power to the valve train 9 in the cylinder head cover 33, an endless cam chain (not shown) is stretched between the camshaft 91 and the crankshaft 51, passing through a cam chain chamber (not shown) provided on one side of the crankcase portion 50a, the cylinder block 31, and the cylinder head 32 in the crankshaft 51 direction, and the camshaft 91 rotates in synchronization with the crankshaft 51 at half the rotational speed. An ignition plug (not shown) is inserted into the combustion chamber 36 from the opposite side of the cam chain chamber in the cylinder head 32 (the other side in the crankshaft 51 direction).

[0035] As shown in FIG. 3 and FIG. 4, which is an enlarged view of a main portion of FIG. 3, in a cylinder head 32 in which the cylinder axis C is tilted forward significantly and nearly horizontal, an intake valve port 40 and an exhaust valve port 41 that open to the combustion chamber ceiling surface 32a are formed so as to extend, while curving upward and downward, from each other.

[0036] The upstream end of the intake port 42 opens toward the top of the cylinder head 32 and is connected to the inlet pipe 6 to form a continuous intake passage 80. As shown in Fig. 5, the downstream end 7a of the throttle body 7 is connected to the upstream end 6e of the inlet pipe 6 via an insulator 8 serving as a connecting member. The downstream end of the exhaust port 43 opens downward in the cylinder head 32 and is connected to the exhaust pipe 38 (see FIG. 2).

[0037] A cylindrical intake valve guide 44 is fitted integrally onto the curved outer wall portion 42a of the intake port 42 in the cylinder head 32, and an intake valve 46 slidably supported by the intake valve guide 44 opens and closes the intake valve port 40 of the intake port 42 that faces the combustion chamber 36. In addition, an exhaust valve 47 slidably supported by an exhaust valve guide 45 fitted integrally onto the curved outer wall portion 43a of the exhaust port 43 in the cylinder head 32 opens and closes the exhaust valve port 41 of the exhaust port 43 that faces the combustion chamber 36.

[0038] The intake valve 46 and the exhaust valve 47 have their umbrella portions 46a, 47a biased upward by a valve spring 48 so as to close the intake valve port 40 and the exhaust valve port 41 facing the combustion chamber 36. However, as shown in FIG. 3, the stem ends 46b, 47b of the intake valve 46 and the exhaust valve 47 are pushed down by an intake rocker arm 94 and an exhaust rocker arm 95 which swing against an intake cam 92 and an exhaust cam 93 of a camshaft 91, respectively, so that the intake valve 46 and the exhaust valve 47 open at a predetermined timing, connecting the intake port 42 and the combustion chamber 36, and the exhaust port 43 and the combustion chamber 36, allowing intake and exhaust to occur at the predetermined timing.

[0039] In the internal combustion engine 30 as described above, an intake device 60 is used that can impart a tumble vortex T, i.e., vertical rotation, of the fuel-air mixture in the combustion chamber 36 in order to obtain more favorable combustion in the combustion chamber 36.

[0040] That is, an inlet pipe 6 is connected to the upstream end of an intake port 42 of an internal combustion engine 30 via an insulator 61 to form a continuous intake passage 80 having a substantially circular cross section. A throttle body 7 is connected to the upstream side of the inlet pipe 6 via an insulator 8 serving as a fixing member.

[0041] The throttle body 7 has an intake passage 70 having a generally circular cross section that constitutes part of an intake passage 80 connected to the combustion chamber 36 of the internal combustion engine 30, and its upstream side is connected to an air cleaner device 86 (see FIG. 2) via a connecting tube 85.

[0042] As shown in Fig. 4, the throttle body 7 is provided with a throttle valve 75. The throttle valve 75 is of a butterfly type and has a throttle valve shaft 76 and a disk-shaped valve element 77 fixed to the throttle valve shaft 76 and rotating integrally therewith. The valve element 77 is fixed to the throttle valve shaft 76 so as to divide the disk into approximately two equal parts. The valve element 77 is rotatably supported in the throttle body 7 by the throttle valve shaft 76 which is oriented perpendicular to the intake flow direction F of the intake passage 70, i.e., approximately horizontally intersecting perpendicularly with the central axis of the intake passage 70. The throttle valve 75 is rotated by an instruction from an operator or the like, and variably controls the flow area of ​​the intake passage 70 to change the intake air flow rate flowing in the intake passage 70.

[0043] The intake passage 80 is divided by a partition 81 from the inlet pipe 6 to the intake port 42 along the intake air flow direction F, into a tumble passage 80A configured so that the intake air that passes through generates a tumble vortex T in the combustion chamber 36, and a main passage 80B excluding the tumble passage 80A. The intake passage 80 is divided by the partition 81 so that the tumble passage 80A is narrower than the main passage 80B. In the present invention, the "tumble passage" refers to a passage of intake air for generating a tumble vortex T in the combustion chamber 36 when the throttle valve 75 is at a low opening, that is, when the internal combustion engine 30 is at a low load.

[0044] The lower portion of the intake passage 80 separated by the partition 81 becomes the tumble passage 80A, and the upper portion becomes the main passage 80B, but the present invention is not limited to this up-down arrangement. Furthermore, in this specification, "upper" and "lower" of the intake passage 80, the intake passage 70, and the throttle valve 75 refer to the direction of the cylinder head 32 or the cylinder head cover 33 in the direction of the cylinder axis C as "upper," and the direction of the crankshaft 51 as "lower," and do not mean absolute "upper" and "lower" in space.

[0045] As shown in FIG. 4, the partition section 81 is configured by an inlet pipe side partition section 81A, an insulator side partition section 81B, and an intake port side partition section 81C, which are positioned consecutively from the upstream side to the downstream side of the intake air flow.

[0046] The main passage 80B on the upper side and the tumble passage 80A on the lower side are defined by a vertical partition 81 that runs from the inlet pipe 6 to the intake port 42, dividing the intake passage 80 downstream of the throttle valve 75 into upper and lower sections, each with an approximately semicircular cross section. The surface of the partition 81 in the width direction of the intake passage 80 and the throttle valve shaft 76 are parallel to each other.

[0047] As shown in FIG. 4, the downstream end 81b of the partition 81, i.e., the downstream end 81b located within the intake port 42 of the cylinder head 32, is bent toward the cylinder block 31 in the cylinder head 32 and is integrally formed therewith, and the terminal end 80Ab of the tumble flow passage 80A is formed so as to face the combustion chamber ceiling surface 32a of the cylinder head 32. 4, the intake air flowing through the tumble flow passage 80A can pass above the umbrella portion 46a of the intake valve 46 and then flow into the cylinder bore 31a, which makes it easier for a tumble vortex T to be generated in the combustion chamber 36. In this way, the tumble flow passage 80A is configured so that the intake air that passes through it generates a tumble vortex T.

[0048] 4, a tumble control valve 65 serving as an intake control valve for controlling the intake flow rate ratio between the tumble flow passage 80A and the main flow passage 80B is disposed adjacent to an upstream end 81a of a partition section 81 formed in the inlet pipe 6. In this embodiment, the tumble control valve 65 is disposed at a distance from the upstream end 81a of the partition section 81, but may be disposed at an upstream end 81aa on the upstream side of the partition section 81. The tumble control valve 65 has a valve shaft 66 and a tumble valve element 67 fixed to the valve shaft 66 and rotating integrally therewith.

[0049] The tumble valve element 67 is formed in a plate-like semicircular disk that closes the opening of the main flow passage 80B near the upstream end 81a of the partition portion 81 in the inlet pipe 6. A valve shaft 66 is attached to one linear end of the tumble valve element 67.

[0050] The valve shaft 66 is rotatably supported by the inlet pipe 6 so as to be parallel to the surface of the partition portion 81 in the width direction of the intake passage 80. As shown in Fig. 5, the valve shaft 66 is connected to an actuator 68 via a reduction gear 69. Also referring to Fig. 8, the valve shaft 66 is rotated by an appropriate predetermined angle by the actuator 68. As the valve shaft 66 rotates, the tumble valve element 67 also rotates, changing the opening degree of the main flow path 80B. As the amount of intake air flowing into the main flow path 80B is adjusted, the amount of intake air in the tumble flow path 80A is also adjusted.

[0051] 4, a fuel injection valve 87 is attached to the throttle body 7 so as to penetrate from the upper outside and to inject fuel toward the intake passage 80. A fuel injection valve 88 is also attached to the inlet pipe 6 so as to penetrate from the upper outside into the main passage 80B and to inject fuel toward the intake valve port 40. When attaching the fuel injection valve 88 to the inlet pipe 6, it is preferable to attach it to the main passage 80B side, which has a larger flow passage cross-sectional area than the tumble passage 80A, in order to prevent fuel from adhering to the intake passage wall surface.

[0052] In this embodiment, fuel injection valves 88, 87 are arranged in inlet pipe 6 and throttle body 7, but the number of fuel injection valves is not limited to two, and may be, for example, one, or only one of fuel injection valves 87, 88 may be attached. Also, a direct injection structure in which a fuel injection valve is arranged in cylinder head 32 or cylinder block 31 and fuel is injected into combustion chamber 36 may be used.

[0053] As shown in FIG. 5, the intake device 60 includes a resonator 100 that communicates with the intake passage 80 inside the inlet pipe 6 via a communication pipe 101 . As shown in Fig. 6, one end 101a of the communicating pipe 101 is connected to a mounting portion 104 protruding from the inlet pipe 6. The other end 101b of the communicating pipe 101 is connected to the resonator 100, as shown in Fig. 7. The inside of the communicating pipe 101 forms a communicating passage 101c that communicates between the inside of the inlet pipe 6 and the inside of the resonator 100.

[0054] As shown in Figs. 9 and 10, the inlet pipe 6 has an attachment portion 104 for attaching one end 101a of the communicating pipe 101, which protrudes from an outer wall surface 6d of the inlet pipe 6. The attachment portion 104 is formed in a tubular shape, and the inside of the attachment portion 104 forms a communicating passage 104a. A flange portion 104b is formed on the outer surface of the attachment portion 104. In this embodiment, the communicating pipe 101 is an integrated part formed integrally with the inlet pipe 6, but the communicating pipe 101 may be a separate part attached to the inlet pipe 6. As shown in Figs. 8 and 9, a communicating hole 102 is formed in the inner wall 6c of the inlet pipe 6, which opens into the communicating passage 104a inside the attachment portion 104.

[0055] 8, the intake passage 80 inside the inlet pipe 6 is divided into a tumble flow passage 80A and a main flow passage 80B by a partition 81. In the inlet pipe 6, a plane passing through the center of the plate of the partition 81 in the thickness direction is defined as a partition center plane Pa, and an extended center plane Pb obtained by extending the partition center plane Pa along the shape of the inlet pipe 6 is defined as an extension center plane Pb. The plane formed by the partition center plane Pa and the extended center plane Pb is defined as a partition center plane P. The inlet pipe 6 is divided by the partition center plane P, and the part on the tumble flow passage 80A side is defined as a tumble flow passage side portion 6a, and the part on the main flow passage 80B side is defined as a main flow passage side portion 6b.

[0056] 8 and 9, the communication hole 102 formed in the inlet pipe 6 is provided at a position on the inner wall surface 6a1 of the tumble flow passage side portion 6a. By providing the communication hole 102 in the tumble flow passage side portion 6a in this manner, the intake air accumulated in the resonator 100 can be actively made to flow toward the tumble flow passage 80A side when the intake valve 46 opens, and the tumble flow can be strengthened.

[0057] 4, the communication hole 102 is formed to be located between the downstream end 7a of the throttle body 7 and the upstream end 81a of the partition portion 81. By providing the communication hole 102 at a position relatively far from the combustion chamber 36, which is a heat generating portion, it is possible to prevent heat from being transmitted to the communication pipe 101 connected to the resonator 100 even when a relatively high temperature airflow flows into the intake passage 80, and therefore it is possible to prevent a decrease in intake efficiency.

[0058] 8, the communication hole 102 is provided downstream of the downstream end 8a of the insulator 8 that connects the throttle body 7 and the inlet pipe 6. Even if the inlet pipe 6 is connected to the throttle body 7 via the insulator 8, the communication hole 102 is not blocked by the insulator 8.

[0059] 10 and 11, the inlet pipe 6 is fixed to the cylinder head 32 via an insulator 61 by a fastening member, a bolt 37. The communicating hole 102 and the mounting portion 104 are disposed at a position not overlapping with the bolt 37 when viewed in the mounting direction of the bolt 37 so that the mounting portion 104, which communicates with the communicating hole 102 and protrudes from the inlet pipe 6, does not interfere with fastening the bolt 37 to the cylinder head 32.

[0060] As shown in Figures 6, 8 and 9, the inner wall 6c of the inlet pipe 6 has cutouts 103 recessed from the inner wall 6c toward the upstream and downstream sides of the intake air with the communication hole 102 in between. The cutouts 103 are deepest near the communication hole 102 and gradually become shallower toward the upstream end 103a and the downstream end 103b. As shown in Figure 12, the lower edge 103c of the cutout 103 is inclined downward from the upstream end 103a to the downstream end 103b, so as to prevent the fuel injected into the inlet pipe 6 from accumulating in the communication hole 102 and the cutouts 103.

[0061] 5, an air amount adjustment valve 110 is provided in the middle of the communication pipe 101 connecting the resonator 100 and the inlet pipe 6 to adjust the amount of air flowing from the resonator 100 into the inlet pipe 6. The air amount adjustment valve 110 has a valve shaft 111 whose axis is in a direction intersecting the air flow direction in the communication pipe 101. As shown in FIG. 13, the valve shaft 111 is formed so that its cross section is circular, and a notch 112 is formed in the valve shaft 111.

[0062] 5, an insertion hole 101d, through which a valve stem 111 of an air amount regulating valve 110 is inserted, is provided at a predetermined position of the communicating pipe 101. The valve stem 111 is inserted into the insertion hole 101d so that a notch 112 is located inside the communicating pipe 101, and is rotatably supported by bearings 105 located on both sides of the communicating pipe 101. A packing member 106 is disposed between the insertion hole 101d and the bearings 105 to prevent air leakage from the communicating pipe 101.

[0063] The air amount regulating valve 110 is provided on the same rotating shaft as the tumble control valve 65. In the intake device 60 of this embodiment, the valve shaft 66 of the tumble control valve 65 and the valve shaft 111 of the air amount regulating valve 110 are formed of the same shaft member 120. When the shaft member 120 is rotated by the actuator 68, the valve shaft 111 of the air amount regulating valve 110 rotates. In the intake device 60 of this embodiment, the valve shaft 66 of the tumble control valve 65 and the valve shaft 111 of the air amount regulating valve 110 are formed as the same part, but the valve shaft 66 and the valve shaft 111 may be formed as separate parts and connected to rotate integrally.

[0064] As shown in Figure 14, when the valve stem 111 of the air amount regulating valve 110 rotates a predetermined angle, the notch 112 opens, resulting in an open valve state where air can pass through the notch 112. As shown in Figure 15, when the valve stem 111 of the air amount regulating valve 110 rotates a predetermined angle, the communicating pipe 101 is closed by the valve stem 111, resulting in a closed valve state.

[0065] As shown in Fig. 16, when the tumble control valve 65 is open, the air amount adjustment valve 110 is closed, and the resonator 100 and the intake passage 80 are not in communication with each other. As shown in Fig. 17, when the tumble control valve 65 is closed, the air amount adjustment valve 110 is open, and air is supplied from the resonator 100 to the intake passage 80. In this way, the tumble control valve 65 and the air amount adjustment valve 110 are configured so that when one valve opens, the other valve closes.

[0066] Next, the effect of strengthening the flow of the tumble flow by providing a resonator 100 downstream of the throttle valve 75 in communication with the intake passage 80 will be described with reference to Figs. 18 and 19 in comparison with an intake system without the resonator 100. As shown in Fig. 18, in these intake systems, the tumble control valve 65 is attached to the upper passage of the intake passage, with the upper side being the main passage 80B and the lower side being the tumble passage 80A. In Fig. 18, the positions of the various points showing the change in pressure in the intake system shown in Fig. 19 are indicated by A and B. Point A is located downstream of the throttle valve 75 and upstream of the upstream end 81a of the partition part 81 that separates the tumble passage 80A and the main passage 80B, and point B is located in the tumble passage 80A.

[0067] 19 shows pressure data for each crank angle in one cycle when the throttle valve 75 is gradually opened for an intake system in which the resonator 100 is connected downstream of the throttle valve 75 and an intake system in which the resonator 100 is not connected downstream of the throttle valve 75, with the horizontal axis representing the crank angle and the vertical axis representing the pressure. The intake passage area in the intake system from downstream of the throttle valve 75 to the intake valve 46 is defined as the intake area downstream of the throttle valve, and this volume is defined as the intake volume downstream of the throttle valve. In these definitions, the area and volume within the resonator 100 are also included when the resonator 100 is connected.

[0068] We will explain the pressure change in the intake passage and the flow of intake air when the resonator 100 is not connected downstream of the throttle valve 75. When the resonator 100 is not connected downstream of the throttle valve 75, it means that the intake system does not have the resonator 100, or that even if the intake system has the resonator 100, it is connected upstream of the throttle valve 75.

[0069] In an intake system in which the resonator 100 is not connected downstream of the throttle valve 75, the intake volume downstream of the throttle valve is not large, so the amount of air stored there is small, and air is taken in from the atmosphere upstream of the throttle valve 75 through the opening of the throttle valve 75 during the intake stroke from when the intake valve 46 opens to when it closes. However, because the opening of the throttle valve 75 is small, the amount of air that increases with the downward movement of the piston 34 cannot be charged in time, and the pressure in the intake port suddenly becomes negative (between the crank angles of about 380 degrees and about 540 degrees in FIG. 19). When the pressure in the intake port suddenly becomes negative in this way, the air in the intake area downstream of the throttle valve expands and is sucked in as the piston 34 descends, weakening the flow and weakening the tumble flow formed in the cylinder.

[0070] Next, we will explain the pressure change in the intake passage and the flow of intake air when the resonator 100 is connected downstream of the throttle valve 75. During the intake stroke from when the intake valve 46 opens to when it closes, the intake volume downstream of the throttle valve is larger by the volume within the resonator 100 compared to when the resonator 100 is not connected, so the mass of the accumulated air is larger.

[0071] When the intake valve 46 opens, the amount of air that increases with the downward movement of the piston 34 is charged from the large amount of air that has accumulated in the intake area downstream of the throttle valve, and the amount of air taken in from the atmosphere upstream of the throttle valve 75 through the opening of the throttle valve 75 is relatively small. Therefore, even when the opening of the throttle valve 75 is small, such as during gradual opening, the change in the negative pressure in the intake port is relatively small (between crank angles of approximately 380 degrees and 540 degrees in FIG. 19). Since the pressure in the intake port does not suddenly become negative in this way, the expansion of the intake air in the intake area downstream of the throttle valve accompanying the piston downward is relatively small, the flow does not decrease, and the flow of the tumble flow formed in the cylinder can be enhanced.

[0072] Next, the effect of the presence or absence of a resonator 100 communicating with the intake passage 80 on the pumping loss (PMEP (kPa)) and fuel efficiency (breakthrough fuel consumption rate BSFC (g / kW-h)) for each of the open and closed states of the tumble control valve 65 was predicted using a desk model.

[0073] 20 is a graph showing the predicted pumping loss and fuel consumption values ​​for a model with a resonator 100 and a model without a resonator 100 when the tumble control valve 65 is open. When the tumble control valve 65 is open, it is assumed that the internal combustion engine is operating at stoichiometric pressure. When the tumble control valve 65 is open, the pumping loss is smaller and the fuel consumption is better when there is no resonator than when there is a resonator.

[0074] 21 is a graph showing the predicted pumping loss and fuel economy values ​​for a model with a resonator 100 and a model without a resonator 100 when the tumble control valve 65 is closed. When the tumble control valve 65 is closed, it is assumed that the internal combustion engine is operating lean. When the tumble control valve 65 is closed, the pumping loss is smaller and the fuel economy is better when there is a resonator than when there is no resonator.

[0075] Depending on the open / closed state of the tumble control valve 65, the advantages of the presence or absence of the resonator 100 in terms of pumping loss and fuel economy are reversed. In the intake device 60 of this embodiment, when the tumble control valve 65 is open, the air amount adjustment valve 110 is closed, and when the tumble control valve 65 is closed, the air amount adjustment valve 110 is open. Therefore, whether the tumble control valve 65 is open or closed, the resonator 100, which has a fuel economy advantage, is connected, so that the fuel economy of the internal combustion engine 30 can be improved.

[0076] Since the intake system 60 for an internal combustion engine according to the embodiment of the present invention is configured as described above, it has the following advantages.

[0077] The intake system 60 has an intake passage 80 that introduces intake air into the combustion chamber 36, an inlet pipe 6 whose interior forms part of the intake passage 80, a throttle body 7 that introduces intake air into the inlet pipe 6, a throttle valve 75 provided inside the throttle body 7 to control the opening degree of the intake passage 80, and a resonator 100. The inlet pipe 6 is disposed downstream of the throttle body 7 and has a partition 81 that divides the intake passage 80 into a tumble flow path 80A and a main flow path 80B along the longitudinal direction, which is the inflow direction of the intake air. The inlet pipe 6 is disposed downstream of the throttle valve 75 and has a tumble control valve 65 and a communication hole 102 that opens into a communication pipe 10) that connects the resonator 100 and the intake passage 80. The communication pipe 101 has an air amount adjustment valve 110 that adjusts the amount of air between the resonator 100 and the inlet pipe 6.

[0078] According to the above configuration, by providing the resonator 100 located downstream of the throttle valve 75 in the inlet pipe 6 and communicating with the intake passage 80, even when the throttle valve 75 is narrowed during operation of the internal combustion engine 30 in a low load range, the intake air flows from the resonator 100 into the intake passage 80 downstream of the throttle valve 75, so that the flow of the intake air in the intake passage 80 is not reduced, and the flow of the tumble flow is strengthened, thereby improving the combustion efficiency. Furthermore, by switching the inflow of air from the resonator 100 into the inlet pipe 6 by the air amount adjustment valve 110 as necessary, the above effect can be further enhanced.

[0079] Furthermore, since the tumble control valve 65 and the air amount adjustment valve 110 are provided on the shaft member 120 which serves as the same rotating shaft, by providing the tumble control valve 65 and the air amount adjustment valve 110 on the shaft member 120 which serves as the same rotating shaft, it is possible to reduce the number of parts by sharing the shaft.

[0080] In addition, the tumble control valve 65 and the air amount adjustment valve 110 have a structure in which when one valve opens, the other valve closes. Therefore, by opening the tumble control valve 65 during stoichiometric operation and closing the air amount adjustment valve 110 between the resonator 100, it is possible to prevent a deterioration in fuel efficiency due to increased pumping loss caused by air flowing in from the resonator 100, which has a large intake volume. On the other hand, by closing the tumble control valve 65 and opening the air amount adjustment valve between the resonator during lean combustion, it is possible to utilize the intake volume of the resonator to promote the formation of a tumble flow and improve combustion efficiency.

[0081] Furthermore, since the communication hole 102 is located between the downstream end 7a of the throttle body 7 and the upstream end 81a of the partition portion 81, by arranging the communication hole 102 communicating with the resonator 100 at a location away from the internal combustion engine 30, which is a heat-generating portion, even if a relatively high temperature airflow flows into the intake passage 80, heat is not transferred to the communication pipe 101 communicating with the resonator 100, and the intake passage 80 is less susceptible to the effects of exhaust heat from the internal combustion engine 30, thereby preventing a decrease in intake efficiency.

[0082] Furthermore, the inlet pipe 6 has an attachment portion 104 to which one end 101a of the communicating tube 101 is attached, and since the attachment portion 104 and the inlet pipe 6 are integrally formed, no fixing parts are required to fix the attachment portion 104 to the inlet pipe 6, which prevents an increase in the number of parts and reduces the amount of processing work.

[0083] Furthermore, a fuel injection valve 87 is provided which injects fuel toward the inside of the intake passage 80, and a notch 103 is provided in the inner wall 6c of the inlet pipe 6 from the upstream side to the downstream side in the intake flow direction, and the communication hole 102 is provided at a position overlapping with the notch 103, thereby preventing the injected fuel from accumulating in the communication hole 102 and the notch 103.

[0084] Although an embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various design modifications are possible without departing from the scope of the present invention. It goes without saying that the present invention includes vehicles, internal combustion engines, and the like, which are embodied in various forms within the scope of the scope of the present invention. For convenience of explanation, the illustrated embodiment has been described with respect to a left-right arrangement, but other left-right arrangements are also included in the present invention as long as they fall within the scope of the gist of the invention. [Explanation of symbols]

[0085] 6...intake passage pipe, 7...throttle body, 30...internal combustion engine, 36...combustion chamber, 60...intake system, 65...tumble control valve, 75...Throttle valve, 80...intake passage, 80A...tumble flow passage, 80B...main flow passage, 81...partition wall, 87...fuel injection valve, 100... resonator, 101... communication tube, 101a... one end, 102... communication hole, 103... notch, 104... mounting portion, 110...Air flow control valve, 120...Shaft member.

Claims

1. An intake system for an internal combustion engine (E) having an intake passage (80) that introduces intake air into a combustion chamber (36), an intake passage pipe (6) whose interior forms part of the intake passage (80), a throttle body (7) that introduces intake air into the intake passage pipe (6), and a throttle valve (75) provided inside the throttle body (7) to control the opening of the intake passage (80), The intake passage pipe (6) is arranged downstream of the throttle body (7), and includes a partition wall (81) that divides the intake passage (80) into a tumble flow path (80A) and a main flow path (80B) along a longitudinal direction, which is the inflow direction of intake air; a resonator (100) communicating with the intake passage (80) via a communication pipe (101); The intake passage pipe (6) has an intake control valve (65) located downstream of the throttle valve (75) for controlling the intake flow rate ratio between the tumble flow path (80A) and the main flow path (80B), and a communication hole (102) opening to the communication pipe (101), The communication pipe (101) is provided with an air amount adjustment valve (110) that opens and closes the inside of the intake passage pipe (6), An intake system for an internal combustion engine, characterized in that the intake control valve (65) and the air amount adjustment valve (110) are provided on a shaft member (120) that serves as the same rotation shaft.

2. (delete)

3. 2. The intake system of an internal combustion engine according to claim 1, wherein the intake control valve (65) and the air amount adjustment valve (110) have a structure in which when one valve (65, 110) opens, the other valve (110, 65) closes.

4. An intake system for an internal combustion engine (E) having an intake passage (80) that introduces intake air into a combustion chamber (36), an intake passage pipe (6) whose interior forms part of the intake passage (80), a throttle body (7) that introduces intake air into the intake passage pipe (6), and a throttle valve (75) provided inside the throttle body (7) to control the opening of the intake passage (80), The intake passage pipe (6) is arranged downstream of the throttle body (7), and includes a partition wall (81) that divides the intake passage (80) into a tumble flow path (80A) and a main flow path (80B) along a longitudinal direction, which is the inflow direction of intake air; a resonator (100) communicating with the intake passage (80) via a communication pipe (101); The intake passage pipe (6) has an intake control valve (65) located downstream of the throttle valve (75) for controlling the intake flow rate ratio between the tumble flow path (80A) and the main flow path (80B), and a communication hole (102) opening to the communication pipe (101), The communication pipe (101) is provided with an air amount adjustment valve (110) that opens and closes the inside of the intake passage pipe (6), An intake system for an internal combustion engine, characterized in that the communication hole (102) is located between the downstream end (7a) of the throttle body (7) and the upstream end (81a) of the partition wall (81).

5. 5. An intake device for an internal combustion engine according to claim 1, 3 or 4, characterized in that the intake passage pipe (6) has an attachment portion (104) to which one end (101a) of the communication pipe (101) is attached, and the attachment portion (104) and the intake passage pipe (6) are integral with each other.

6. a fuel injection valve (87) for injecting fuel toward the inside of the intake passage (80); 6. An intake device for an internal combustion engine according to claim 1, wherein a notch (103) extending from the upstream side to the downstream side in the intake air flow direction is provided in the inner wall (6c) of the intake passage pipe (6), and the communication hole (102) is provided at a position overlapping with the notch (103).

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