Patent Application
20110114052
This application is based on and claims priority under 35 U.S.C. ยง119 to Japanese Patent Application 2009-264331, filed on Nov. 19, 2009, the entire content of which is incorporated herein by reference.
This disclosure relates to an air intake apparatus for an internal combustion engine.
According to a known air intake apparatus for an internal combustion engine, an inner surface of a casing formed around a rotational axis of a valve element, i.e., the inner surface surrounding a rotation region of the valve element in a direction perpendicular to the rotational axis of the valve element, is formed into a cylindrical shape and is coaxial with the rotational axis of the valve element. An intake port and a discharge port are formed in an opening manner at different portions of the inner surface in a rotating direction of the valve element. Accordingly, the inner surface that extends from the intake port to the discharge port is formed to be an arc surface coaxial with the rotational axis of the valve element. Such air intake apparatus is disclosed in JP2008-8150A (specifically, paragraph 0019 and FIG. 5), for example.
Therefore, according to the air intake apparatus disclosed in JP2008-8150A, a recess void along the arc surface formed coaxially with the rotational axis of the valve element serves as a dead space (i.e., an extra space) in an air intake path from the intake port to the discharge port. Then, a portion of air flowing from the intake port towards the discharge port may enter the recess void, which may lead to an increase of a pressure loss of the air flowing into the discharge port. A flow speed of the air may decrease accordingly. Consequently, an air filling rate, a mixing rate of the air and fuel tends to decrease, which may disturb an increase of an output of an internal combustion engine.
A need thus exists for an air intake apparatus for an internal combustion engine which is not susceptible to the drawback mentioned above.
According to an aspect of this disclosure, an air intake apparatus for an internal combustion engine includes a casing including an intake port and a discharge port, a rotary valve rotatable around a rotational axis within the casing and including a valve element that controls a connecting state between the intake port and the discharge port, and an inner surface forming portion formed at an inner surface of the casing along the rotational axis of the rotary valve and defined from the intake port to the discharge port, a distance of the inner surface from the rotational axis being shorter than a maximum rotational radius of the valve element.
According to another aspect of this disclosure, an air intake apparatus for an internal combustion engine includes a casing including an intake port and a discharge port, a valve element provided at an inside of the casing and rotating to control a connecting state between the intake port and the discharge port, and an inner surface forming portion formed at an inner surface of the casing along a rotational radius of the valve element and defined from the intake port to the discharge port, a distance of the inner surface from the rotational axis being shorter than the rotational radius of the valve element.
The foregoing and additional features and characteristics of this disclosure will become more apparent from the following detailed description considered with the reference to the accompanying drawings, wherein:
Embodiment disclosed here will be explained with reference to the attached drawings. An air intake apparatus for an internal combustion engine according to each of the embodiments is applied to a vehicle equipped with a four-cylinder engine that serves as the internal combustion engine, for example. In the embodiment, directions and orientations such as left, right, front, rear, top, and bottom correspond to those when viewed from an occupant of a vehicle equipped with the air intake apparatus for the internal combustion engine.
A first embodiment will be explained as below. As illustrated in
The surge tank B and the casing C are integrally formed by a connection of resin molded products. A throttle valve is connected to the inlet 1 of the surge tank B so that outside air, of which a volume of airflow is adjusted by the throttle valve, is sucked via the inlet 1 into the air storage void 2.
The air intake passage D is connected to an air intake portion Fa for each of four cylinders of an engine F serving as the internal combustion engine. That is, according to the present embodiment, four of the air intake passages D are individually and respectively connected to four of the cylinders of the engine F. The air intake portion Fa is connected to a cylinder head of the engine F via an intake pipe 3. A fuel injection nozzle is provided at a downstream portion of the intake pipe 3.
Each of the air intake passages D includes a first intake passage D1 having a shorter path length to the surge tank B, a second intake passage D2 having a longer path length to the surge tank B compared to the first intake passage D1, and a third intake passage D3 connected to the air intake portion Fa.
The rotary valve E controls the airflow to the air intake portion Fa from the air intake passage D. The rotary valve E includes a rotor K rotatably driven around a rotational axis X by an electric motor J and an angle sensor 9 detecting a rotational angle of the rotary valve E. The rotor K includes four valve elements 4 mounted at the respective four air intake passages D. The valve elements 4 are made of resin and are rotatable about the rotational axis X within the casing C.
The valve elements 4 are accommodated within bore portions 8 respectively, formed at the casing C. Specifically, four of the bore portions 8 are provided, corresponding to the four air intake passages D. Each of the bore portions 8 includes an inner peripheral surface 8a having substantially a cylindrical shape and being coaxial with the rotational axis X of the valve element 4.
An end portion of the first intake passage D1 (i.e., a portion facing the rotary valve E) serves as a first intake port G1. An end portion of the second intake passage D2 (i.e., a portion facing the rotary valve E) serves as a second intake port G2. A start portion of the third intake passage D3 (i.e., a portion facing the rotary valve E) serves as the discharge port H. All of the ports G1, G2, and H are open at the inner peripheral surface 8a of the bore portion 8 individually.
As illustrated in
Each of the valve elements 4 rotates about the rotational axis X to thereby control or adjust a connection state between the intake port G (G1, G2) and the discharge port H. As illustrated in
As illustrated in
As illustrated in
The circular side plates 5 provided at the respective valve elements 4 adjacent to each other are connected by means of a connection shaft 7 as illustrated in
As illustrated in
An inner surface of the casing C, which extends from the second intake port G2 to the discharge port H, along the rotational axis X of the valve element 4, serves as an inner peripheral surface 12 (inner surface) that is a portion of an inner peripheral surface 8a of the bore portion 8 and that is disposed between the second intake port G2 and the discharge port H. The inner peripheral surface 12 is constituted by an inner surface forming portion 13 that forms a curved surface (surface), of which a distance from the rotational axis X is shorter than a maximum rotational radius R (a rotational radius) of the valve element 4 and which is integrally formed at the casing C.
That is, as illustrated in
The inner peripheral surface 12 having the curved surface is connected to the facing lateral wall surface P2a (i.e., the first inner surface) along a tangent line L1 of the facing lateral surface P2a of the second intake passage D2 at the second intake port G2. In addition, the inner peripheral surface 12 is connected to the facing lateral wall surface P3a (i.e., the second inner surface) along a tangent line L2 of the facing lateral wall surface P3a of the third intake passage D3 at the discharge port H. In the aforementioned manner, the inner peripheral surface 12 is formed into the curved surface shape protruding towards the rotational axis X.
As illustrated in
That is, the casing C includes a body portion 17 where the insertion opening 15 is formed and the cover member 16 where each of the discharge ports H is provided. Each of the inner surface forming portions 13 is formed at the body portion 17 to constitute the inner peripheral surface 12.
Then, as illustrated in
In a case of an extremely low speed rotation of the engine F, the rotational position of the rotor K is determined as illustrated in
In a case of a low speed rotation of the engine F, the rotational position of the rotor K is determined as illustrated in
In a case of a medium speed rotation of the engine F, the rotational position of the rotor K is determined as illustrated in
In a case of a high speed rotation of the engine F, the rotational position of the rotor K is determined as illustrated in
In order to smoothly connect the facing lateral wall surfaces P2a and P3a of the second and third intake passages D2 and D3 adjacent to each other via the bore portion 8, the inner peripheral surface 12 of the bore portion 8 defined between the second intake port G2 and the discharge port H is formed into the curved surface projecting towards the rotational axis X. As a result, a dead space of the bore portion 8, where a portion of the air flowing towards the discharge port H from the intake port G may enter, is reduced to thereby restrain a pressure loss of the air flowing to the discharge port H and a decrease of the flow speed of the air. Accordingly, regardless of any rotations (i.e., any rotational positions) of the rotor K, the pressure loss of the air may be reduced.
The control of rotating each of the valve elements 4 in response to the number of rotations of the engine F is achieved by the control of the electric motor J based on the number of rotations of the engine F. In such control, the rotor K is controlled to rotate in the forward direction (i.e., a counterclockwise rotation in
A second embodiment will be explained with reference to
Accordingly, in a case of mounting the rotary valve E to the body portion 17, the rotary valve E is inserted through the insertion opening 15 in the direction perpendicular to the rotational axis X and is mounted at the inside of the body portion 17 as illustrated in
The inner surface of the casing C, which extends from the second intake port G2 to the discharge port H, along the rotational axis X of the valve element 4, may be formed by the inner surface forming portion 13, of which a distance from the rotational axis X is shorter than the maximum rotational radius R of the valve element 4 and which has a flat surface. In addition, the inner surface of the casing C, which extends from the second intake port G2 to the discharge port H, along the rotational axis X of the valve element 4, may be formed by the inner surface forming portion 13, of which a distance from the rotational axis X is shorter than the maximum rotational radius R of the valve element 4 and which has a curved surface dented in a direction away from the rotational axis X. Further, the inner surface of the casing C, which extends from the second intake port G2 to the discharge port H, along the rotational axis X of the valve element 4, may be formed by the inner surface forming portion 13, of which a distance from the rotational axis X is shorter than the maximum rotational radius R of the valve element 4 and which has a curved surface dented in a direction away from the rotational axis X and a curved surface protruding towards the rotational axis X, both of the curved surfaces being smoothly connected to each other. That is, the inner surface of the casing C defined from the intake port G2 to the discharge port H may be formed into any shape as long as the air flowing and taken from the intake port G2 smoothly flows into the discharge port H. Therefore, the shape of the inner peripheral surface 12 of the casing C defined from the intake port G to the discharge port H may be appropriately specified depending on a connecting angle of each of the intake passages D1, D2, and D3 relative to the bore portion 8, a cross-section area of each of the intake passages D1, D2, and D3, and the like.
According to the aforementioned embodiments, the air from the intake port G to the discharge port H flows along the inner peripheral surface 12 of which a distance from the rotational axis X is shorter than the maximum rotational radius R of the valve element 4. That is, the inner peripheral surface 12 defined from the intake port G to the discharge port H achieves a smooth connection between a direction where the air is taken in from the intake port G and a direction where the air flows out from the discharge port H. A pressure loss of the air flowing towards the discharge port H is reduced and a decrease of the flow speed of the air is minimized. Consequently, an air filling rate, a mixing rate of the air and fuel, and the like are prevented from decreasing, which may cause an increase of an output of the internal combustion engine.
In addition, according to the aforementioned embodiments, the inner surface forming portion 13 includes the surface smoothly connecting the facing lateral wall surface P2a of the intake port G2 and the facing lateral wall surface P3a of the discharge port H.
Further, according to the aforementioned embodiments, the pair of circular side plates 15 are provided at respective ends of the valve element 4 along the rotational axis X, the pair of circular side plates 15 being coaxial with the rotational axis X, and the inner surface forming portion 13 is arranged between the pair of circular side plates 15.
Accordingly, both ends of the rotational void of the valve element 4 in a direction of the rotational axis X are defined by plate surfaces of the pair of circular side plates 15 provided at the respective ends of the valve element 4 along the rotational axis X and coaxial therewith. Thus, shapes of the respective ends of the rotational void of the valve element 4 along the rotational axis X are constant regardless of the rotation of the valve element 4, thereby stabilizing the airflow from the intake port G to the discharge port H. In addition, because the inner surface forming portion 13 is arranged between the pair of circular side plates 5, the inner surface forming portion 13 is prevented from interfering with the rotation of the valve element 4.
Further, according to the aforementioned first and second embodiments, the inner surface forming portion 13 is integrally formed at the casing C, and the casing C includes the insertion opening 15 into which the rotary valve E is inserted and mounted in a direction perpendicular to the rotational axis X and the cover member 16 covering the insertion opening 15.
Accordingly, the rotary valve E is inserted in the direction perpendicular to the rotational axis X and mounted at the casing C where the inner surface forming portion 13 is integrally formed and thereafter the insertion opening 15 of the rotary valve E is closed by the cover member 16. Thus, at the time of mounting the rotary valve E to the casing C, the mounting of the inner surface forming portion 13 at the casing C is not necessary, which leads to a simplified assembling of the rotary valve E and the inner surface forming portion 13. The cover member 16 may partially or fully close the insertion opening 15 of the rotary valve E.
Further, according to the aforementioned second embodiment, the casing C includes the insertion opening 15 into which the rotary valve E is inserted and mounted in the direction perpendicular to the rotational axis X, and the inner surface forming portion 13 is integrally formed at the cover member 16 covering the insertion opening 15.
Accordingly, the rotary valve E is inserted, in the direction perpendicular to the rotational axis X, into the inside of the casing C where the inner surface forming portion 13 is not provided, i.e., the inner surface forming portion 13 does not disturb the mounting of the rotary valve E to the casing C. Then, after the rotary valve E is mounted at the inside of the casing C, the inner surface forming portion 13 is mounted at the same time as when the insertion opening 15 of the rotary valve E is closed by the cover member 16. Consequently, the simplified assembly of the rotary valve E and the inner surface forming portion 13 is obtained. At this time, the cover member 16 may partially or fully close the insertion opening 15 of the rotary valve V.
Further, according to the aforementioned first and second embodiments, the pair of circular side plates 15 are integrally formed with each other via the valve element 4.
Thus, the simplified configuration of the rotary valve E that is mounted at the inside of the casing C so as to be rotatable is simplified.
Further, according to the aforementioned first and second embodiments, each of the pair of circular side plates 15 is configured in such a manner that the metallic circular disc 6 is insert-molded by resin to each of the pair of circular side plates 15.
Thus, the strength of each of the circular side plates 15 is enhanced by the metallic circular disc 6 so that a torsional rigidity of the rotary valve E that is rotatably operated may increase.
The principles, preferred embodiment and mode of operation of the present invention have been described in the foregoing specification. However, the invention which is intended to be protected is not to be construed as limited to the particular embodiments disclosed. Further, the embodiments described herein are to be regarded as illustrative rather than restrictive. Variations and changes may be made by others, and equivalents employed, without departing from the spirit of the present invention. Accordingly, it is expressly intended that all such variations, changes and equivalents which fall within the spirit and scope of the present invention as defined in the claims, be embraced thereby.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2009-264331 | Nov 2009 | JP | national |
