JP7600425B2 - Intake system for internal combustion engine - Google Patents

Description

The present invention relates to an intake device for an internal combustion engine in which the intake passage is divided into a main passage and a tumble passage, and a resonator is provided that communicates with the intake passage.

A structure for dividing the 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 connected to the intake passage is not provided, the amount of intake air accumulated in the intake port is small, and when the internal combustion engine is operating in the low load range, the opening of the throttle valve is small. Therefore, during the intake stroke from when the intake valve opens to when it closes, the volume of the intake port side increases as the piston descends, 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 suddenly becomes negative pressure, the flow in the intake passage becomes weak, and the flow of the tumble flow decreases.

International Publication No. WO2018/16391

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.

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.

According to the above 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 of the internal combustion engine in the low load range, intake air flows from the resonator into the intake passage downstream of the throttle valve, so that the flow of intake air in the intake passage is not reduced, and the flow of tumble flow is strengthened, improving combustion efficiency. Furthermore, the above effect can be further enhanced by switching the flow of air from the resonator into the intake passage pipe using an air flow control valve as necessary.

In the above configuration, the intake control valve and the air flow adjustment valve can also be arranged on a shaft member that serves as the same rotating shaft.

According to the above configuration, by arranging the intake control valve and the air flow adjustment valve on a shaft member that serves as the same rotating shaft, the number of parts can be reduced by sharing the shaft.

In the above configuration, the intake control valve and the air flow adjustment valve may have a structure in which when one valve opens, the other valve closes.

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 losses caused by air flowing in from the resonator, which has a large intake volume. On the other hand, 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.

In the above configuration, the communication hole may be positioned between the downstream end of the throttle body and the upstream end of the partition.

According to the above configuration, by locating the communication hole that connects to 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 that connects to the resonator, making it less susceptible to the effects of exhaust heat from the internal combustion engine and preventing a decrease in intake efficiency.

In the above configuration, the intake passage pipe has an attachment portion to which one end of the communicating pipe is attached, and the attachment portion and the intake passage pipe may be formed as an integral part.

According to the above configuration, fixing parts for fixing the mounting portion to the intake passage pipe are not required, which prevents an increase in the number of parts and reduces the processing effort.

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.

The above configuration prevents injected fuel from accumulating in the communication holes and notches.

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 of the internal combustion engine in the low load range, intake air flows from the resonator into the intake passage downstream of the throttle valve, so that the flow of intake air in the intake passage is not reduced, and the flow of the tumble flow is strengthened, improving combustion efficiency. Furthermore, the above effect can be further enhanced by switching the inflow of air into the resonator with an air flow control valve as necessary.

1 is a right side view of a motorcycle equipped with a power unit having an intake structure for an internal combustion engine according to a first embodiment of the present invention. 2 is a rear right side view of the motorcycle of FIG. 1 with a body cover removed. 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, and equipped with the intake structure for an internal combustion engine according to the first embodiment. FIG. FIG. 4 is an enlarged view of a main portion of FIG. 3 . FIG. 2 is a schematic diagram showing the periphery of an intake pipe and a resonator. 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. FIG. 2 is a vertical cross-sectional view of the resonator. FIG. 5 is an enlarged view of a main part of FIG. 4 . FIG. 9 is an enlarged sectional perspective view of a main portion of FIG. 8 . FIG. 2 is a left side view showing the vicinity of the throttle body and the inlet pipe. FIG. 4 is a perspective view showing the periphery of an attachment portion of the inlet pipe. 1 is a view of the periphery of the communication hole as viewed from inside the inlet pipe. FIG. 4 is a perspective view showing a valve stem and a cutout portion of the air amount regulating valve. 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. 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. 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. 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. FIG. 2 is a schematic diagram of an intake passage showing a region downstream of a throttle valve. FIG. 17 is a diagram showing pressure fluctuations at the points shown in FIG. 16 in the cycle of the internal combustion engine. 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. 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.

Based on Figures 1 to 21, an intake device for an internal combustion engine according to one embodiment of the present invention will be described.

In addition, the directions of front, rear, left, right, up and down in the description of this specification and the claims are based on the directions of the vehicle when a power unit equipped with an internal combustion engine intake device 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 81, which acts as a partition wall dividing them along the intake flow direction F, will be described as the "upper" side, and the lower side as the "lower" side. In addition, in the figures, the arrows FR indicate the front of the vehicle, LH indicate the left side of the vehicle, RH indicate the right side of the vehicle, and UP indicate the upper side of the vehicle.

Figure 1 shows the right side 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. Figure 2 shows the rear right side of the motorcycle 1 in Figure 1 with the body cover 10 removed.

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

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 FIG. 2, a pair of left and right main pipes 22 are connected at their rear ends via a connecting frame 23 arranged in the vehicle width direction, and the main pipes 22 rise diagonally rearward from the connecting frame 23 forming an inclined part 22a, which is then bent midway to reduce the inclination as it extends rearward.

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 part 1A of the vehicle body, a handlebar 14 is provided above and journaled on the head pipe 20, and a front fork 15 extends below and journals the front wheel 16 at its lower end.

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 swingably connected and supported to the bracket 24 via a link member 25.

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 the crankshaft 51 is arranged in the vehicle width direction and rotatably supported at the front part of the power unit case 50 constituting the crankcase section 50a, with the cylinder axis C tilted significantly forward to a nearly horizontal state, and the end of the hanger arm 52 protruding forward from the lower end of the power unit case 50 is connected via a link member 25 attached to the bracket 24 of the main pipe 22 so as to be able to swing freely up and down.

The power unit 3 is fastened to the front of the power unit case 50 that constitutes the crankcase section 50a so that the cylinder block 31, cylinder head 32, and cylinder head cover 33 that constitute the internal combustion engine 30 are stacked one on top of the other, and the power transmission case section 55 that is equipped with a belt-type continuously variable transmission and the like extends integrally from the crankcase section 50a to the rear left side, and a rear axle 56 that is the output shaft of the power unit 3 is provided at the rear of the power unit 3, and the rear wheel 17 is attached to it. 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 section 55 at the rear of the power unit 3 and the rear of the main pipe 22.

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. An air cleaner device 86 connected to the throttle body 7 via a connecting tube 85 is disposed above the power transmission case 55. Meanwhile, 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.

Figure 3 is a side cross-sectional view of the power unit 3 in Figure 2, taken out and shown in approximately the same orientation as in Figure 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.

The power unit case 50 is formed by combining a left case half 50L and a right case half (not shown) which are split left and right. The right case half forms the right half of the crankcase section 50a, and the left case half 50L, the front of which forms the left half of the crankcase section 50a, extends rearward to form a power transmission case section 55 which 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.

The reduction gear mechanism 57 is housed inside the right open surface 55R at the rear of the power transmission case 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 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 55 and the reduction gear mechanism 57.

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

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

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 crankshaft 51 direction of the crankcase 50a, cylinder block 31, and cylinder head 32, 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 (the other side of the crankshaft 51 direction) in the cylinder head 32.

As shown in Figure 3 and Figure 4, which is an enlarged view of a key portion of Figure 3, in a cylinder head 32 in which the cylinder axis C is tilted forward almost to a nearly horizontal position, an intake valve port 40 and an exhaust valve port 41 open to the combustion chamber ceiling surface 32a are formed so that they extend, curving away from each other vertically, from the intake port 42 and exhaust port 43, respectively.

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 Figure 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).

A cylindrical intake valve guide 44 is fitted integrally to 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 facing the combustion chamber 36. An exhaust valve 47 slidably supported by an exhaust valve guide 45 fitted integrally to 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 facing the combustion chamber 36.

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. As shown in FIG. 3, the stem ends 46b, 47b of the intake valve 46 and the exhaust valve 47 are pushed down by the intake rocker arm 94 and the exhaust rocker arm 95 which swing against the intake cam 92 and the exhaust cam 93 of the camshaft 91, respectively, so that the intake valve 46 and the exhaust valve 47 open at the specified timing, connecting the intake port 42 and the combustion chamber 36, and connecting the exhaust port 43 and the combustion chamber 36, and allowing intake and exhaust to occur at the specified timing.

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.

That is, an inlet pipe 6 is connected to the upstream end of the intake port 42 of the internal combustion engine 30 via an insulator 61 to form a continuous intake passage 80 with a generally 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 fixed member.

The throttle body 7 has an intake passage 70 with a generally circular cross section which constitutes part of the 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 Figure 2) via a connecting tube 85.

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, etc., and variably controls the flow area of the intake passage 70 to change the intake flow rate flowing into the intake passage 70.

The intake passage 80 is divided by a partition 81 from the inlet pipe 6 to the intake port 42 along the intake flow direction F, into a tumble passage 80A configured to generate 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 an intake passage 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.

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

As shown in Figure 4, the partition portion 81 is composed of an inlet pipe side partition portion 81A, an insulator side partition portion 81B, and an intake port side partition portion 81C, which are positioned consecutively from the upstream side to the downstream side of the intake flow.

The main passage 80B on the upper side in the figure and the tumble passage 80A on the lower side in the figure are each defined by a substantially semicircular cross section by dividing the intake passage 80 downstream of the throttle valve 75 into upper and lower parts by a vertical partition 81 that runs from the inlet pipe 6 to the intake port 42.
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.

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 side and formed integrally with the cylinder head 32, 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.
Therefore, 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, as shown by the small and medium arrow in Figure 4, 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.

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

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

The valve shaft 66 is rotatably supported in the inlet pipe 6 so as to be parallel to the surface of the partition 81 in the width direction of the intake passage 80. As shown in Figure 5, the valve shaft 66 is connected to an actuator 68 via a reduction gear 69. Also referring to Figure 8, the valve shaft 66 is rotated to a predetermined angle by the actuator 68. As the valve shaft 66 rotates, the tumble valve body 67 also rotates, changing the opening 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.

As shown in Figure 4, a fuel injection valve 87 is attached to the throttle body 7, penetrating it from the outside above, and is arranged to inject fuel toward the intake passage 80. A fuel injection valve 88 is also attached to the inlet pipe 6, penetrating the main passage 80B from the outside above, and arranged 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 cross-sectional area than the tumble passage 80A, in order to prevent fuel from adhering to the intake passage wall surface.

In this embodiment, fuel injection valves 88, 87 are arranged in the inlet pipe 6 and the 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 the fuel injection valves 87, 88 may be installed. Also, a direct injection structure in which the fuel injection valve is arranged in the cylinder head 32 or the cylinder block 31 and fuel is injected into the combustion chamber 36 may be used.

As shown in FIG. 5, the intake system 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 tube 101 is connected to a mounting portion 104 protruding from the inlet pipe 6. The other end 101b of the communicating tube 101 is connected to the resonator 100 as shown in Fig. 7. The inside of the communicating tube 101 forms a communicating passage 101c that communicates between the inside of the inlet pipe 6 and the inside of the resonator 100.

9 and 10, the inlet pipe 6 is provided with an attachment portion 104 for attaching one end 101a of the communication pipe 101, which protrudes from the outer wall surface 6d of the inlet pipe 6. The attachment portion 104 is formed in a tubular shape, and the inside forms a communication passage 104a. A flange-shaped portion 104b is formed on the outer surface of the attachment portion 104. In this embodiment, the communication pipe 101 is an integral part formed integrally with the inlet pipe 6, but it may be a structure in which the communication pipe 101 is attached to the inlet pipe 6 separately from the inlet pipe 6. As shown in Figs. 8 and 9, the inner wall 6c of the inlet pipe 6 is provided with a communication hole 102 that opens into the communication passage 104a inside the attachment portion 104.

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, the plane passing through the center of the plate of the partition 81 in the thickness direction is defined as the partition center plane Pa, and the partition center plane Pa is defined as an extended center plane Pb extending along the shape of the inlet pipe 6, and the plane formed by these partition center plane Pa and extended center plane Pb is defined as the partition center plane P. Dividing the inlet pipe 6 by the partition center plane P, the part on the tumble flow passage 80A side is defined as the tumble flow passage side 6a, and the part on the main flow passage 80B side is defined as the main flow passage side 6b.

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, as shown in Figures 8 and 9. 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 when the intake valve 46 opens, and the tumble flow can be strengthened.

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 locating the communication hole 102 in a position relatively far from the combustion chamber 36, which is a heat generating portion, it is possible to prevent heat from being transferred to the communication pipe 101 connected to the resonator 100, even when a relatively high temperature airflow flows into the intake passage 80, and it is possible to prevent a decrease in intake efficiency.

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.

10 and 11, the inlet pipe 6 is fixed to the cylinder head 32 via the insulator 61 by the bolt 37, which is a fastening member. The communication hole 102 and the mounting part 104 are positioned so as not to overlap with the bolt 37 when viewed in the mounting direction of the bolt 37, so that the mounting part 104, which communicates with the communication hole 102 and protrudes from the inlet pipe 6, does not interfere with fastening the bolt 37 to the cylinder head 32.

As shown in Figures 6, 8 and 9, the inner wall 6c of the inlet pipe 6 has a notch 103 recessed from the inner wall 6c toward the upstream and downstream sides of the intake air, sandwiching the communication hole 102. The notch 103 is deepest near the communication hole 102 and gradually becomes shallower toward the upstream end 103a and downstream end 103b. As shown in Figure 12, the lower edge 103c of the notch 103 is downwardly inclined from the upstream end 103a to the downstream end 103b, so as to prevent the injected fuel injected into the inlet pipe 6 from accumulating in the communication hole 102 and the notch 103.

Furthermore, as shown in Fig. 5, an air volume adjustment valve 110 is provided in the middle of the communication pipe 101 that connects the resonator 100 and the inlet pipe 6 to adjust the volume of air flowing from the resonator 100 into the inlet pipe 6. The air volume adjustment valve 110 has a valve shaft 111 whose axis is in a direction that intersects with the air flow direction in the communication pipe 101. As shown in Fig. 13, the valve shaft 111 is formed so that its cross-sectional shape is circular, and a notch 112 is formed in the valve shaft 111.

As shown in Figure 5, a through hole 101d is provided at a predetermined position of the communicating pipe 101, through which the valve shaft 111 of the air amount adjustment valve 110 is inserted. The valve shaft 111 is inserted into the through hole 101d so that the 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 provided between the through hole 101d and the bearings 105 to prevent air leakage from the communicating pipe 101.

The air quantity adjustment 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 quantity adjustment 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 quantity adjustment 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 quantity adjustment 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 together.

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

As shown in Figure 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. As shown in Figure 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.

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 explained with reference to Figures 18 and 19, in comparison with an intake system without a resonator 100. As shown in Figure 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. Figure 18 shows the positions of the various points that represent the change in pressure in the intake system shown in Figure 19, with A and B. Point A is located downstream of the throttle valve 75 and upstream of the upstream end 81a of the partition 81 that separates the tumble passage 80A and the main passage 80B, and point B is located within the tumble passage 80A.

Figure 19 shows pressure data at various locations for each crank angle in one cycle when the throttle valve 75 is slowly 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. These definitions also include the area and volume within the resonator 100 when the resonator 100 is connected.

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, this refers to when the intake system does not have the resonator 100, or when the intake system has the resonator 100 but is connected upstream of the throttle valve 75.

In an intake system where 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 charge of the amount of air that increases with the descent of the piston 34 is not in time, and the pressure inside the intake port suddenly becomes negative (between crank angles of approximately 380 degrees and 540 degrees in Figure 19). When the pressure inside 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.

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 accumulated air is larger.

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 rarely suddenly becomes negative, the expansion of the intake air in the intake area downstream of the throttle valve accompanying the piston downward movement is relatively small, the flow does not decrease, and the flow of the tumble flow formed in the cylinder can be enhanced.

Next, a desk model was used to predict the effect of the presence or absence of a resonator 100 communicating with the intake passage 80 on pumping loss (PMEP (kPa)) and fuel economy (net fuel consumption rate BSFC (g/kW-h)) for both the open and closed states of the tumble control valve 65.

Figure 20 is a graph showing 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 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 economy is better when there is no resonator than when there is a resonator.

Figure 21 is a graph showing 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.

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 control valve 110 is closed, and when the tumble control valve 65 is closed, the air amount control 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, making it possible to improve the fuel economy of the internal combustion engine 30.

The intake device 60 of the internal combustion engine according to the embodiment of the present invention is configured as described above, and thus provides the following effects.

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 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 volume adjustment valve 110 that adjusts the volume of air between the resonator 100 and the inlet pipe 6.

According to the above configuration, by providing a 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 throttled during operation in the low load range of the internal combustion engine 30, intake air flows from the resonator 100 into the intake passage 80 downstream of the throttle valve 75, so that the flow of intake air in the intake passage 80 is not reduced, and the flow of the tumble flow is strengthened, improving combustion efficiency. Furthermore, the above effect can be further enhanced by switching the flow of air from the resonator 100 into the inlet pipe 6 using the air flow control valve 110 as necessary.

Furthermore, since the tumble control valve 65 and the air volume adjustment valve 110 are mounted on the shaft member 120 as a common rotating shaft, by mounting the tumble control valve 65 and the air volume adjustment valve 110 on the shaft member 120 as a common rotating shaft, the number of parts can be reduced by sharing the shaft.

In addition, the tumble control valve 65 and the air quantity control valve 110 are structured so that when one valve opens, the other closes. Therefore, by opening the tumble control valve 65 during stoichiometric operation and closing the air quantity control 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 quantity control 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.

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 locating 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.

In addition, the inlet pipe 6 has an attachment portion 104 to which one end 101a of the communicating pipe 101 is attached, and since the attachment portion 104 and the inlet pipe 6 are integral, no fixing parts are required to fix the attachment portion 104 to the inlet pipe 6, preventing an increase in the number of parts and reducing the amount of processing work.

Furthermore, a fuel injection valve 87 is provided which injects fuel into the intake passage 80, and a notch 103 is provided in the inner wall 6c of the inlet pipe 6 from the upstream side toward 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.

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.

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...Axial member.

Claims (6)

An intake system for an internal combustion engine (E) having an intake passage (80) for introducing intake air into a combustion chamber (36), an intake passage pipe (6) whose interior forms a part of the intake passage (80), a throttle body (7) for introducing intake air into the intake passage pipe (6), and a throttle valve (75) provided inside the throttle body (7) for controlling an opening degree of the intake passage (80),
the intake passage pipe (6) is disposed downstream of a throttle body (7), and includes a partition wall (81) that divides the intake passage (80) into a tumble flow passage (80A) and a main flow passage (80B) along a longitudinal direction, which is an inflow direction of intake air;
A resonator (100) is connected to the intake passage (80) via a communication pipe (101),
the intake passage pipe (6) is located downstream of the throttle valve (75) and includes an intake control valve (65) for controlling the intake flow rate ratio between the tumble flow passage (80A) and the main flow passage (80B), and a communication hole (102) opening into the communication pipe (101);
The communication pipe (101) is provided with an air amount control valve (110) that opens and closes the inside of the intake passage pipe (6),
An intake system for an internal combustion engine, wherein the intake control valve (65) and the air amount adjustment valve (110) are provided on a shaft member (120) serving as a common rotating shaft. (delete) 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) is opened, the other valve (110, 65) is closed. An intake system for an internal combustion engine (E) having an intake passage (80) for introducing intake air into a combustion chamber (36), an intake passage pipe (6) whose interior forms a part of the intake passage (80), a throttle body (7) for introducing intake air into the intake passage pipe (6), and a throttle valve (75) provided inside the throttle body (7) for controlling an opening degree of the intake passage (80),
the intake passage pipe (6) is disposed downstream of a throttle body (7), and includes a partition wall (81) that divides the intake passage (80) into a tumble flow passage (80A) and a main flow passage (80B) along a longitudinal direction, which is an inflow direction of intake air;
A resonator (100) is connected to the intake passage (80) via a communication pipe (101),
the intake passage pipe (6) is located downstream of the throttle valve (75) and includes an intake control valve (65) for controlling the intake flow rate ratio between the tumble flow passage (80A) and the main flow passage (80B), and a communication hole (102) opening into the communication pipe (101);
The communication pipe (101) is provided with an air amount control 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 a downstream end (7a) of the throttle body (7) and an upstream end (81a) of the partition wall (81). 5. An intake device for an internal combustion engine as claimed in claim 1, 3 or 4, characterized in that the intake passage pipe (6) has a mounting portion (104) to which one end (101a) of the communicating pipe (101) is attached, and the mounting portion (104) and the intake passage pipe (6) are integral with each other. 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 as claimed in claim 1, 3 or 5, characterized in that a notch (103) is provided in an inner wall (6c) of the intake passage pipe (6) from the upstream side to the downstream side in the intake air flow direction, and the communication hole (102) is provided at a position overlapping with the notch (103).

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