JP2005105968A - Intake device of engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intake device of an engine capable of increasing the responsiveness of the inflow of suction air into cylinders by the opening/closing operations of throttle valves by installing the throttle valves in independent intake passages and reinforcing tumble flow in a low speed area with less intake amount while maintaining the responsiveness of the suction air. <P>SOLUTION: In this intake device of the engine, rotary throttle valves for regulating intake air amount are disposed in the independent intake passages of the cylinders. To reinforce the tumble flow in the cylinders at low speed areas, a through hole 10 allowing the intake passages 7d in the throttle valves to communicate with upstream side passages 6c in the throttle valves are formed in a first inner wall part 7a on the upstream side of the intake air when the throttle valve 7 is fully closed (a). The rotating direction of the throttle valve 7 is set so that an opening part 10b on the downstream side of the intake air can open the valve from the upper passage wall 6f side of the downstream passage 6b in the throttle valve. When the throttle valve 7 is opened (b) at low speed areas, the intake air flows linearly from the opening part 10b on the downstream side of the intake flow to the upper passage wall 6f side through the through hole 10. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an engine intake device, in particular, a rotary throttle valve for adjusting the intake air amount, in which the valve itself forms part of the wall surface of the intake passage, in the middle of the independent intake passage of each cylinder. The present invention relates to an intake device for an engine arranged in a direction.

  2. Description of the Related Art In an engine intake device, a butterfly throttle valve in which a thin valve plate is fixed to a valve shaft that penetrates an intake passage has been used as an intake air amount control for adjusting an intake air amount of an engine.

  On the other hand, recently, in order to avoid intake resistance such as a valve shaft in a butterfly type throttle valve, a type using a rotary type throttle valve has been proposed.

For example, Patent Document 1 proposes a rotary throttle valve in which the shape of the intake passage wall between the valve hole and the intake passage matches when the throttle valve is fully opened. Japanese Patent Application Laid-Open No. H10-228561 proposes a device that is waterproof and dustproof for a reduction gear in a drive system for driving a rotary throttle valve.
JP 2001-73813 A JP 2001-248462 A

  On the other hand, in the intake control to the engine, it is required to improve the combustibility by strengthening the tumble flow in the cylinder in a region where the intake amount in the low speed region is small.

  A widely used structure for enhancing tumble flow is that each independent intake passage is provided with a butterfly-type intake flow control valve formed so that the intake passage is throttled when the valve is opened. Is closed in a low speed region where the tumble flow is weak, thereby adjusting the intake flow derived from each intake port to each cylinder, thereby strengthening the tumble flow in each cylinder.

  However, when a throttle valve is provided in each independent intake passage, it is difficult to place the intake valve together with the intake flow control valve.

  In other words, if a throttle valve is arranged downstream of the intake flow control valve, the intake air rectified by the intake flow control valve to strengthen the tumble is attenuated by the throttle valve, and the original effect of the intake flow control valve can be achieved. It becomes impossible. On the other hand, if the intake flow control valve is arranged downstream of the throttle valve, the intake capacity from the throttle valve to the cylinder increases, and accordingly, the intake system delay (intake response delay) is likely to occur, and the tumble flow is reduced. In the low speed range that you want to strengthen, the throttle valve seems to be closed, so the intake air is already throttled upstream of the intake flow control valve in the independent intake passage, and the intake throttle effect at the intake flow control valve is halved, It becomes difficult to control the main intake air that leads to strengthening the tumble flow.

  In view of such a problem, the present invention installs a throttle valve in each independent intake passage to enhance the responsiveness of intake air flow into the cylinder accompanying the opening / closing operation of the throttle valve and maintain the responsiveness of the intake air. An engine air intake device that realizes the enhancement of tumble flow in a region where the intake air amount in a low speed region is small is provided.

  In order to solve this problem, an intake device for an engine according to the present invention includes a rotary throttle valve for adjusting the intake air amount, in which the valve itself forms a part of the wall surface of the intake passage in the middle of the independent intake passage of each cylinder. In the engine intake device arranged with the valve shaft direction directed toward the crankshaft direction, the throttle from the intake passage wall surface side for strengthening the intake flow to enhance the tumble flow in the cylinder on the intake downstream side of the throttle valve The rotational position of the throttle valve and the direction of operation of the drive actuator that rotationally drives the throttle valve are set so that the valve opens, and the intake of the throttle valve that is upstream of the intake when the throttle valve is fully closed On the passage wall surface, when the throttle valve is fully closed, the intake passage in the throttle valve and the intake upstream side An intake passage and having a communicating portion communicating.

  Here, when the throttle valve is in the valve opening start position, the communication portion is formed so as to have an opening upstream of the intake air in the intake passage in the throttle valve relative to the opening position downstream of the intake air. In addition, in the cross section of the intake passage as viewed from one end side in the crankshaft direction, the basic shape of the outer periphery of the throttle valve is substantially cylindrical, and in the range of the wall surface of the intake passage having the communication portion, the cylinder inside the case housing the throttle valve A space portion is formed between the wall surface and the intake passage wall surface having the communication portion. In addition, the outer peripheral shape of the throttle valve is a cylindrical shape in each opening range of the intake upstream and downstream, and an outer wall surface along the inner wall surface of the throttle valve outside the opening range. Further, the communication part is formed by a through hole in the wall surface of the intake passage of the throttle valve. Further, the communication portion is formed by removing the intake passage wall surface while leaving the intake downstream side of the intake passage wall surface of the throttle valve.

  Also, the shape of the opening on the intake downstream side of the throttle valve is angular so that both corners of the opening edge that opens to the front of the throttle valve have an opening area larger than both corners of the opening edge that opens later. ing. In addition, corners connected to both corners of the opening edge that opens earlier are formed on the wall surface of the intake passage of the throttle valve so as to be gradually angled from the intake upstream side toward the intake downstream side. Further, the corner portion of the intake passage wall surface on the engine body side connected to the intake downstream side of the throttle valve is formed so as to be gradually rounded from the opening portion on the intake downstream side of the angular throttle valve toward the intake downstream side. .

  In addition, a gap that is attracted by the intake negative pressure in the cylinder is provided between the outer peripheral surface of the throttle valve and the case of the throttle valve.

  According to the present invention, a throttle valve is installed in each independent intake passage to improve the response of intake air flow into the cylinder accompanying the opening / closing operation of the throttle valve, and while maintaining the response of the intake air, It is possible to provide an engine intake device that realizes enhancement of tumble flow in a small amount region.

  In other words, the throttle valve itself has the same shape of the intake passage inner wall as the intake passage to suppress the increase in intake resistance and effectively use the communication part and the throttle operation in the operation region where the intake amount is low and the tumble flow is required to be strengthened. Can strengthen the tumble flow.

  Also, by providing a space for buffering the intake air communicating with the communication portion, the flow rate of intake air into the throttle valve can be increased to enhance the tumble flow.

  In addition, although the communication part is formed to realize the strengthening of the tumble flow in the region where the intake amount in the low speed region is small, the same shape of the intake passage in the throttle valve and the intake passage upstream and downstream of the intake should be kept as much as possible. Therefore, it is possible to suppress an increase in intake resistance during a high load (when the throttle is open).

  Further, the communication portion for realizing the strengthening of the tumble flow in the region where the intake amount in the low speed region is small can be easily formed by a simple process.

  Also, the tumble flow can be enhanced by increasing the intake flow rate with a small throttle opening.

  Furthermore, it is possible to reduce the intake air leakage amount in the region where the intake air amount in the low speed region is small.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of an engine intake device of the present invention will be described in detail with reference to the accompanying drawings.

<Configuration Example of Engine Intake Device of Present Embodiment>
FIG. 1 and FIG. 2 are diagrams showing a configuration example of an engine intake device of the present embodiment, and FIG. 2 is an intake passage viewed from one end side in the crankshaft direction of one cylinder of the engine intake device of FIG. It is a cross section. In addition, in FIG. 1, although the example of the intake device of a 4-cylinder engine is shown, it is not limited to this.

  The intake device 1 includes a duct 2 that takes in intake air from the atmosphere, an air cleaner 3 that is connected to the duct 2 and removes dust and the like in the intake air, a surge tank 4 that introduces intake air from the air cleaner 3, and an engine body 8a from the surge tank 4. Independent intake passages 5, 5 formed for each cylinder for supplying intake air to each of the cylinders.

  In the middle of each independent intake passage 5, 5, a horizontally long rotary throttle valve device 6 is parallel to the crankshaft (not shown) direction of the engine, that is, with respect to the independent intake passages 5, 5. It extends so as to be substantially perpendicular. The throttle valve device 6 includes a rotary throttle valve 7, a case 6 a that houses the throttle valve 7, and an actuator 8 that rotationally drives the throttle valve 7.

  In this example, the surge tank 4 and the upstream portion 5a (see FIG. 2) of the independent intake passages 5 and 5 extending from the surge tank 4 to the rotary throttle valve device 6 are integrally molded, and the throttle valve 7 In the case 6a for storing the intake, the upstream in-throttle passage 6c and the in-throttle downstream passage 6b forming a part of the independent intake passage 5 are integrally formed on the upstream side and the downstream side, and these integrally formed parts And the three parts of the engine body 8a are joined to form an intake device. The surge tank 4 is located below the throttle valve device 6 in the vertical direction of the engine body 8a. The upstream portion 5a of the independent intake passage 5 connected to the surge tank 4 extends from the surge tank 4 to the engine body 8a in the vertical direction. After extending upward, it curves in a U shape toward the engine body 8a.

  As shown in FIG. 2, a circular outer cylindrical throttle valve 7 that slides along the longitudinal direction of a cylindrical space formed inside the case 6a of the throttle valve device 6 is inserted. The outer edge of the throttle valve 7 as viewed from the direction is circular. The throttle upstream passage 6c and the intake passage of the upstream portion 5a of the independent intake passage 5 connected to the upstream passage 6c are arranged so as to be adjacent to each other when viewed from the rotational axis direction of the throttle valve 7. doing. Further, a first inner wall portion 7a and a second inner wall portion 7b that are substantially parallel to each other when viewed from the rotation axis direction of the throttle valve 7 are formed inside the throttle valve 7 so as to face each other. An intake passage 7d in the throttle valve having a substantially rectangular cross section having 7a and 7b is formed. The amount of intake air passing through the throttle valve intake passage 7d is adjusted by the rotation of the throttle valve 7.

  On the engine body 8a side of the throttle valve 7 is formed the above-mentioned throttle downstream passage 6b that can communicate with the throttle valve intake passage 7d. The throttle downstream passage 6b is formed in the cylinder head 8c. It is fixed so as to communicate with the intake port 11. The intake port 11 communicates with a combustion chamber 13 formed by the cylinder head 8c and the cylinder block 8b via an intake valve 12 that opens and closes in synchronization with the rotation of the crankshaft. A fuel injection valve 14 is disposed above the cylinder head 8c in the vertical direction of the engine body 8a. Fuel injected from the fuel injection valve 14 is introduced into the combustion chamber 13 through the intake port 11.

  Further, in the state of FIG. 2 (rotation position of the throttle valve 7 at low speed and low load), the downstream end 7f of the second inner wall portion 7b, that is, the lower edge 17c of the opening edge 17 to be described later and the downstream inside passage 6b in the throttle. Since the opening 15 with the passage wall 6f is small (the opening area is a predetermined value or less. The opening area indicates the opening area of the intake passage 7d in the throttle valve with respect to the downstream passage 6b in the throttle). The intake air having a high flow velocity supplied downstream from the engine 7 is guided to the upper passage wall 6f side of the in-throttle downstream passage 6b, and the main intake air flows toward the upper passage wall 6f side and the upper wall surface 11f of the intake port 11. Since the engine speed is low and the tumble flow generated in the cylinder is weak, a relatively large tumble flow is generated in the combustion chamber 13. It is possible to. As a result, the mixing property of the fuel injected from the fuel injection valve 14 and the intake air is improved, the homogeneity of the air-fuel mixture in the combustion chamber 13 is improved, and even in an air-fuel ratio state leaner than the stoichiometric air-fuel ratio. Good combustion is possible.

  When the throttle valve 7 is further rotated clockwise from the state of FIG. 2, the opening 17 between the intake passage 6c in the throttle and the intake passage 7d in the throttle valve, the downstream passage 6b in the throttle, and the intake passage in the throttle valve. 7d and the opening 15 are further narrowed, the amount of intake air is reduced, and the tumble flow in the combustion chamber 13 is strengthened. When the throttle valve 7 continues to rotate in the same direction and the flow direction of the intake passage 7d in the throttle valve and the flow direction of the downstream flow passage 6b in the throttle approach a right angle, the intake passage 7d in the throttle valve and the downstream in the throttle Communication with the passage 6b is blocked.

  On the contrary, when the throttle valve 7 is further rotated counterclockwise from the state of FIG. 2, the opening area of the opening 15 between the in-throttle downstream passage 6b and the in-throttle valve intake passage 7d is increased. In this state, in FIG. 2, the distance between the downstream end 7f of the second inner wall portion 7b and the upstream end of the upper passage wall 6f of the throttle inner downstream passage 6b is widened, and the opening area of the opening 15 becomes a predetermined value or more. In addition, the uneven distribution of the main intake air flow in the independent intake passage 5 on the downstream side of the throttle valve 7 (that is, the state where the intake air flow rate is high) is reduced. In this state, since the engine rotation speed is high, the piston stroke amount per unit time is large, and the tumble flow strength is inevitably increased, so that the turbulence enhancement by the throttle valve 7 is not necessary.

<One Configuration Example of Rotary Throttle Valve Device of the Present Embodiment>
(First example of throttle valve)
FIG. 3 is a conceptual diagram showing a first configuration example of the rotary throttle valve device of the present embodiment. The same reference numerals as those in FIGS. 1 and 2 correspond to the same functional parts.

  In the rotary type throttle valve device of FIG. 3, as shown in FIG. 3 (c), when the throttle valve 7 is fully opened, the first inner wall portion 7a and the second inner wall portion 7b of the throttle valve 7 and the in-throttle downstream passage 6b. As shown in FIG. 3A, the shape of the passage wall of the upstream upstream passage 6c matches the first inner wall portion 7a on the upper side of the intake air when the throttle valve 7 is fully closed. A through hole 10 is provided to communicate the intake passage 7d and the upstream passage 6c in the throttle. In this example, as shown in FIG. 2, the intake passage is arranged so that intake is performed from the upper right side of the cylinder. Therefore, the throttle valve 7 is moved from the fully closed state of FIG. As in the open state in the low speed region and the fully open state in (c), the valve opening is controlled to rotate counterclockwise and the valve closed in the clockwise direction on the drawing of FIG. In the throttle inner downstream passage 6b, air is supplied along the upper passage wall 6f to cause a tumble flow in the cylinder (combustion chamber 13).

  In FIG. 3B, conventionally, intake air from the opening 10a upstream of the intake air flows from the opening 10b downstream of the intake air to the in-throttle downstream passage 6b via the intake passage 7d in the throttle valve. In this example, in addition to the intake air from the opening 10a upstream of the intake air, the intake air linearly flows from the opening 10b downstream of the intake air to the in-throttle downstream passage 6b through the through hole 10 of the first inner wall 7a. By adopting such a configuration, the straightness of the intake air from the opening 10b downstream of the intake air to the upper passage wall 6f portion of the in-throttle downstream passage 6b is enhanced, and the flow velocity of the intake air in the low speed region is enhanced. It is possible to reinforce the tumble flow in the cylinder generated by the intake air. Further, the intake air flows into both the through hole 10 and the opening 10a upstream of the intake into the intake passage 7d in the throttle valve, so that the amount of inflowing air increases, and the opening area of the opening 10b downstream of the intake is reduced accordingly. This can further enhance the tumble flow in the low speed range. The opening area of the through hole 10 is preferably about 20% of the cross-sectional area of the intake passage in consideration of the opening degree of the throttle valve 7 that should enhance the tumble flow.

  Here, the outer wall surface of the first inner wall portion 7a is formed along the inner wall surface, a space 10c is formed between the first inner wall portion 7a and the case 6a, and a buffer of air passing through the through hole 10 is formed. It is preferable. The space 10d formed between the second inner wall portion 7b and the case 6a is a result of maintaining the symmetry of the throttle valve 7 and simplifying the molding, and has no special function.

  As shown in FIG. 3 (c), in the vicinity of the fully opened state, the wall surface of the intake passage 7d in the throttle valve coincides with the wall surface of the downstream passage 6b in the throttle and the upstream passage 6c in the throttle, and the through hole 10 has almost no influence on the intake air. Without a large amount of smooth intake.

  FIG. 4 is a diagram showing a specific shape of the first configuration example of the rotary throttle valve device 6 of the present embodiment. The same reference numerals as those in FIGS. 1 to 3 correspond to the same functional parts.

  FIG. 4A is a cross section of the intake passage as viewed from one end side in the crankshaft direction in the first configuration example in the low speed range. The actual through hole 10 is formed in an oval cross section in the first inner wall portion 7a as shown in the fields (b) and (c) of FIG. Also, the spaces 10c and 10d shown in FIG. 3 (b) are formed as recessed portions that do not communicate with each other as shown in FIG. 4 (a) in order to simplify the formation.

  FIG. 4B is a view of FIG. 4A viewed from the direction of arrow A (on the upstream side of the slot valve). FIG. 4C is a view of only the throttle valve 7 excluding the case 6a as seen from the direction of the arrow A. As shown in the figure, the through hole 10 of the first inner wall 7a and the opening 10b between the second inner wall 7b and the in-throttle downstream passage 6b appear to communicate with each other when viewed from the direction of the arrow A.

(Second example of throttle valve)
FIG. 5 is a conceptual diagram showing a second configuration example of the rotary throttle valve device 6 of the present embodiment. The same reference numerals as those in FIGS. 1 and 2 correspond to the same functional parts. FIG. 5 is a diagram showing a case where the throttle valve 7 is in the low speed range. The fully closed and fully open states are the same as (a) and (c) of FIG. 4 except for the difference in the shape of the first inner wall 7a ′ on the intake air upstream side, and thus the description thereof is omitted.

  In FIG. 5, similarly to FIG. 4B, the intake air amount is controlled by the opening 10b downstream of the intake air. In this example, the lower portion is removed from the portion of the through hole 10 in FIG. 4B in the first inner wall portion 7a ′. In this state, the intake air from the opening 10a ′ upstream of the intake air flows from the opening 10b to the in-throttle downstream passage 6b, and particularly near the upper passage wall 6f, from the vicinity of the upper portion of the intake upstream opening 10a ′ to the downstream of the intake air. 10b passes through the throttle downstream passage 6b in a straight line. By adopting such a configuration, the flow rate from the opening 10b downstream of the intake air to the in-throttle downstream passage 6b is increased to enhance the air flow velocity of the intake air in the low speed region, thereby causing the tumble in the cylinder generated by the intake air. It is possible to strengthen the flow. The remaining intake passage wall surface 7a 'does not adversely affect the straightness to the intake air flow along the intake passage in the high speed range (near the fully open throttle valve).

  FIG. 6 is a view showing a specific shape of the second configuration example of the rotary throttle valve device 6 of the present embodiment. The same reference numerals as those in FIGS. 1, 2, and 5 correspond to the same functional parts.

  FIG. 6A is a cross section of the intake passage as seen from the one end side in the crankshaft direction in the second configuration example in the low speed range. FIG. 6B shows only the throttle valve 7 excluding the case 6a. As shown in the figure, the actual intake upstream opening 10a ′ is provided below the first inner wall 7a ′ as an opening connected to the throttle upstream passage 6c. The opening 10a ′ is viewed from the arrow A side. A part of 10a 'and the opening 10b on the downstream side of the intake air between the second inner wall 7b and the case 6a appear to communicate with each other.

  According to this example, the communication part for realizing the strengthening of the tumble flow in the region where the intake amount in the low speed region is small can be easily formed by a simple process.

<Improvement example of rotary type throttle valve device of this embodiment>
(Throttle valve improvement example)
FIG. 7 is a view showing an improvement example of the rotary type throttle valve device of the present embodiment.

  In the first and second examples, the intake downstream opening 10b between the second inner wall portion 7b and the in-throttle downstream passage 6b connected to the case 6a is formed as shown in FIG. 4B or FIG. As shown in FIG. 2, the lower edge of the opening 10b is formed in a large R shape.

  FIG. 7A is a view of the throttle valve 7 of this example as viewed from the intake air downstream side, and FIG. 7B is a perspective view thereof. The opening edge 17 of the opening 10b downstream of the intake of the throttle valve 7 is set to be angular as indicated by both corners 17a and 17b, and the length of the lower edge 17c is set to be long. In this way, the two corners of the opening edge that opens to the front of the throttle valve 7 are angular so that the opening area is larger than the two corners of the opening edge that opens later, and as shown in FIG. As shown in the center figure (the initial valve opening state), the area of the opening 10b downstream of the intake air is the same, and the intake air area can be further reduced (the opening of the throttle valve 7 has been reduced). Can be strengthened.

  In the example of FIG. 7, as shown in FIGS. 7A and 7B, an example in which the shape of the intake passage is changed near the opening 10b downstream of the intake of the throttle valve 7 is shown. It is desirable to adjust the formation of the intake passage and gradually change it into the angular shape of FIG. 7 over the entire intake passage 7d in the throttle valve (toward the downstream side of the intake).

(Improvement of intake passage downstream of intake)
In the example of FIG. 7, the improvement example of the shape of the intake passage of the throttle valve 7 has been shown. However, the in-throttle downstream passage 6b downstream of the intake is deformed in accordance with the deformation of the opening edge 17 of the throttle valve 7 downstream of the intake. By doing so, the intake flow in the intake passage can be made more stable.

  FIG. 8 is a view showing a modification of the in-throttle downstream passage 6b corresponding to the deformation of the shape of the intake passage of the throttle valve 7 of FIG.

  FIG. 8A is a cross section of the intake passage when the throttle valve of this example is viewed from one end side in the crankshaft direction. In FIG. 8A, the throttle valve 7 is in a fully opened position. FIG. 8B is a view showing the shape of the intake passage in each of the sections aa, bb, and cc in FIG. 8A.

  The opening 10b on the downstream side of the intake of the throttle valve 7 in FIG. 8 is more open than both corners (17a, 17b) of the opening edge that opens earlier as shown in FIG. Since it has an angular shape so as to increase the area, at the upstream end side of the in-throttle downstream passage 6b, both corners of the lower edge are angular as shown in the cross section c, so that the throttle downstream of the intake air. The inner / downstream passage 6 b coincides with the opening edge 17 of the opening 10 b downstream of the intake of the throttle valve 7. In the cross section b, the corners at both corners of the lower edge are somewhat less angular, and the R at both corners is formed larger. In the cross section a, there is almost no angularity at both corners of the lower edge, and a cylindrical intake passage is formed. In the connection part with the engine main body 8a, it corresponds with the cylindrical intake passage in the engine main body 8a.

  In this way, steps in the intake passage are eliminated, and disadvantages such as disturbance of the intake flow are prevented.

<Another Improvement Example of the Rotary Throttle Valve Device of the Present Embodiment>
In a rotary type throttle valve device in which only the valve shaft penetrates the intake passage, but the entire throttle valve penetrates the intake passage, the airtightness between the throttle valve that rotates and slides against the case (intake leakage leakage) Prevention, especially leakage on the engine side downstream of the case intake, is more important. In this improvement example, an improvement in the airtightness between the throttle valve and the case that rotate and slide with each other is shown.

(An example of improving airtightness)
9 and 10 show an example in which intake air leakage is prevented by improving the adhesion between the throttle valve 7 and the case 6a that rotate and slide relative to each other.

  In FIG. 9, an arrow X indicates the intake direction. Reference numeral 91 denotes an O-ring having elasticity such as resin, and a gap that is somewhat wider than the gap for rotating and sliding is provided between the throttle valve 7 and the case 6a. Since the generated negative pressure upstream of the throttle valve 7 is small when the engine is stopped and when the load is high, the throttle valve 7 is positioned substantially at the center of the case 6a as shown in FIG. As shown in FIG. 10 (a), in the low speed and low load range such as when idling, the negative pressure generated downstream of the throttle valve 7 increases, so that the throttle valve 7 itself is attracted to the engine and the O-ring 91 is compressed and deformed. The throttle valve 7 is brought into close contact with the case 6a on the engine side to improve airtightness.

(Another example of improving airtightness)
FIG. 11 shows another example in which intake air leakage is prevented by improving the adhesion between the throttle valve 7 and the case 6a that rotate and slide with each other.

  In FIG. 11A, an O-ring 111 is arranged between the case 6a via a bearing 110, and the throttle valve 7 is brought into close contact with the case 6a on the engine side due to the negative pressure of the engine to improve the airtightness.

  In FIG. 11 (b), a coating 112 is provided between the throttle valve 7 and the case 6a to increase the airtightness by rotational sliding so that the airtightness between the throttle valve 7 and the case 6a is enhanced. become.

  In addition, although each specific example and improvement example shown by this embodiment may be applied independently, respectively, the effect is further show | played by applying in combination. These combinations are also included in the technical idea of the present invention.

It is a figure which shows the structural example of the intake device of the engine of this embodiment. 2 is a cross section of an intake passage as viewed from one end side in the crankshaft direction of the intake device of the engine of FIG. 1. It is a conceptual diagram which shows the 1st structural example of the rotary type throttle valve apparatus of this embodiment. It is a figure which shows the specific shape of the 1st structural example of the rotary type throttle valve apparatus of this embodiment. It is a conceptual diagram which shows the 2nd structural example of the rotary type throttle valve apparatus of this embodiment. It is a figure which shows the specific shape of the 2nd structural example of the rotary type throttle valve apparatus of this embodiment. It is a figure which shows the example of improvement of the rotary type throttle valve apparatus of this embodiment. It is a figure which shows the modification of the downstream in-throttle passage 6b of the intake downstream corresponding to the deformation | transformation of the shape of the intake passage of the throttle valve of FIG. A first example is shown in which intake air leakage is prevented by improving the adhesion between the throttle valve 7 and the case 6a that rotate and slide relative to each other. An example in which intake air leakage is prevented by increasing the adhesion between the throttle valve 7 and the case 6a that rotate and slide relative to each other will be described. It is a figure which shows the other example which prevents intake air leakage by improving the adhesiveness of the throttle valve 7 and the case 6a which mutually rotate and slide.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Intake device 5 Independent intake passage 6 Throttle valve device 6a Case 6b Downstream passage in throttle (intake passage downstream of intake)
6c Throttle upstream passage (intake passage upstream of intake)
7 Throttle valve 7a, 7a 'First inner wall (intake passage wall surface)
7d Throttle valve intake passage 8a Engine body 10 Through hole (communication part)
10a, 10a 'Opening upstream of intake 10d Opening downstream of intake 13 Combustion chamber (cylinder)
17 Opening edge 17a Corner 17b Corner

Claims (10)

An intake device for an engine in which a rotary throttle valve for adjusting the intake air amount, in which the valve itself forms a part of the wall surface of the intake passage, is arranged in the middle of the independent intake passage of each cylinder with the valve shaft direction directed toward the crankshaft direction In
The rotational position of the throttle valve and the throttle valve are opened on the downstream side of the intake side of the throttle valve so that the throttle valve opens from the side of the intake passage wall that enhances the intake flow in order to enhance the tumble flow in the cylinder. Set the direction of operation of the drive actuator that rotates,
A communicating portion for communicating the intake passage in the throttle valve and the intake passage on the upstream side of the throttle valve with the intake passage wall surface of the throttle valve on the upstream side of the intake when the throttle valve is fully closed An air intake device for an engine characterized by comprising:   The communication portion is formed so as to have an opening upstream of the intake air relative to an opening position downstream of the intake air in the intake passage when the throttle valve is in a valve opening start position. Item 2. The engine intake system according to Item 1.   In the intake passage cross section viewed from one end side in the crankshaft direction, the basic shape of the outer periphery of the throttle valve is cylindrical, and in the range of the intake passage wall surface having the communication portion, the cylindrical inner wall surface of the case housing the throttle valve and the The engine intake device according to claim 2, wherein a space portion is formed between the intake passage wall surface having the communication portion.   4. An outer peripheral shape of the throttle valve is substantially cylindrical in each of the opening ranges of the intake upstream and downstream, and is an outer wall surface along the inner wall surface of the passage of the throttle valve outside the opening range. The engine intake system described.   The engine intake device according to claim 2, wherein the communication portion is formed by a through hole in an intake passage wall surface of the throttle valve.   3. The engine intake device according to claim 2, wherein the communication portion is formed by removing the intake passage wall surface while leaving the intake downstream surface of the intake passage wall surface of the throttle valve.   The shape of the opening on the intake downstream side of the throttle valve is angular so that both corners of the opening edge that opens to the front of the throttle valve increase the opening area than both corners of the opening edge that opens later. The engine intake system according to claim 1.   The corner portion connected to both corners of the opening edge that opens earlier is formed on the intake passage wall surface of the throttle valve so as to be gradually angled from the intake upstream side toward the intake downstream side. 8. An intake device for an engine according to 7.   The corner portion of the intake passage wall surface on the engine main body side connected to the intake downstream side of the throttle valve is formed so as to gradually round from the opening on the intake downstream side of the angular throttle valve toward the intake downstream side. 8. The engine intake system according to claim 7, wherein   The engine intake device according to claim 1, wherein a gap that is attracted by an intake negative pressure in the cylinder is provided between an outer peripheral surface of the throttle valve and a case of the throttle valve.

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