JP4191721B2 - Engine intake system - Google Patents

Description

  The present invention relates to a throttle body having a horizontal intake passage, a butterfly-type throttle valve that is attached to a valve shaft that is rotatably supported in a bearing hole of the throttle body and opens and closes the intake passage, and a throttle body A sensor housing attached to one side of the engine and a sensor unit having a throttle sensor for detecting the opening of the throttle valve and a negative pressure sensor for detecting the intake negative pressure in the intake passage. Is related to the improvement of the intake system of the engine.

Such an intake device for an engine is already known as disclosed in Patent Document 1.
JP 2002-332936 A

  As shown in FIG. 8, in the conventional engine intake system, the negative pressure transmission paths 35 for transmitting the intake negative pressure generated in the intake passage 2 of the throttle body 1 to the negative pressure sensor 20 are perpendicular to each other during engine operation. The first passage 35 a and the second passage 35 b connected to each other are configured in a bowl shape, and consideration is given so that the blowback gas of the engine does not reach the negative pressure sensor 20. However, since the first passage 35a is arranged so as to open to the intake passage 2 greatly away from the horizontal plane H including the axis of the intake passage 2 (= the axis of the valve shaft 5a of the throttle valve 5), There is a risk that fuel drops adhering to the inner peripheral surface of the road 2 will flow down and enter the first passage 35a. When a plurality of types of throttle bodies having different diameters of the intake passage 2 are manufactured by casting or injection without changing the shape of the mounting surface 15 of the sensor unit 16 in the throttle body 1, a large-diameter intake passage is used. At 2L, the inner peripheral surface of the intake passage 2 expands so as to delete the end portion of the first passage 35a on the intake passage side, so the first passage 35a becomes shorter and the negative pressure transmission passage 35 As a result, the bending effect of the blown gas is allowed to enter the negative pressure sensor 20.

  The present invention has been made in view of such problems, and it is difficult for foreign matters such as fuel and carbon adhering to the inner peripheral surface of the intake passage to enter the negative pressure transmission path, and for the sensor housing in the throttle body. Even when multiple types of throttle bodies with different diameters of the intake passage are manufactured by casting without changing the shape of the mounting part, the first passage of the negative pressure transmission path is prevented from being greatly shortened. An object of the present invention is to provide an intake device for the engine, which can prevent the blow-back gas from entering the negative pressure sensor in any throttle body.

In order to achieve the above object, the present invention provides a throttle body having a horizontal intake passage, and a butterfly that is attached to a valve shaft that is rotatably supported by a bearing hole of the throttle body so as to open and close the intake passage. And a sensor unit having a sensor housing attached to one side of the throttle body and a throttle sensor for detecting the opening of the throttle valve and a negative pressure sensor for detecting intake negative pressure in the intake passage. In the engine intake device in which the intake passage and the negative pressure sensor communicate with each other via a negative pressure transmission path , the negative pressure sensor is located downstream of the throttle valve valve shaft in the side view of the sensor unit. In addition, it is arranged adjacent to the throttle sensor above the axis of the intake passage, and those negative pressure sensors and scans along the axis of the intake passage. The position of Ttorusensa arranged to overlap in the left-right directions as viewed from the side of the sensor unit, wherein the negative pressure transmission path, on half surfaces of the intake passage in proximity to a horizontal plane including the axis of the end portion intake passage A first passage that opens, a groove-shaped second passage formed between the joint surfaces of the throttle body and the sensor housing so as to bend and extend upward at a substantially right angle from the other end of the first passage; A first feature is that the third passage formed in the sensor housing extends from the upper end of the passage to the opposite side of the first passage and reaches the negative pressure sensor, and is configured in a crank shape.

  According to the second aspect of the present invention, in addition to the first feature, the second passage and a seal groove that surrounds the second passage and is fitted with a seal member are formed on the joint surface on the throttle body side. It is characterized by.

  In addition to the first or second feature of the present invention, the second passage is formed in a polygon formed by sequentially connecting the centers of three or more fastening portions that fasten the throttle body and the sensor housing with straight lines. The third feature is that they are arranged along one straight line.

  According to the first feature of the present invention, since the negative pressure transmission path opens in the upper half circumferential surface of the intake passage, the ingress of fuel droplets adhering to the inner peripheral surface of the intake passage and flowing down into the negative pressure transmission path Can be prevented.

  Even if foreign matter such as fuel or carbon enters the negative pressure transmission path from the intake passage due to the intake air blowback phenomenon, the negative pressure sensor is far away from the opening of the negative pressure transmission path to the intake passage. In addition, since the negative pressure transmission path is formed in a crank shape having a large flow path resistance by the first to third paths, the foreign matter cannot reach the negative pressure sensor. It can be protected to ensure its function and durability.

  In addition, when manufacturing multiple types of throttle bodies with different diameters of the intake passage by casting or injection without changing the shape of the sensor unit mounting portion in the throttle body, especially the throttle body of a large-diameter intake passage. Even when manufacturing the cylinder, the amount removed by the inner peripheral surface of the intake passage is extremely small. Therefore, any type of throttle body can ensure the bending effect of the negative pressure transmission path and can be used as a foreign object negative pressure sensor. Can always be prevented.

  According to the second feature of the present invention, when the throttle body is molded, the second passage and the seal groove can be formed simultaneously with the mounting surface for the sensor unit, which can contribute to a reduction in manufacturing cost.

  According to the third feature of the present invention, the fastening force of the fastening portion can be efficiently applied to the sealing member around the second passage, and the sealing around the second passage can be reliably performed.

  Embodiments of the present invention will be described below on the basis of preferred embodiments of the present invention shown in the accompanying drawings.

  1 is a longitudinal plan view of an intake system for an engine according to the present invention, FIG. 2 is a sectional view taken along line 2-2 in FIG. 1, FIG. 3 is a sectional view taken along line 3-3 in FIG. 3 is a sectional view taken along the arrow 4 in FIG. 3, FIG. 5 is a sectional view taken along line 5-5 in FIG. 3, FIG. 6 is a sectional view taken along line 6-6 in FIG. It is sectional drawing.

  1 to 3, the engine intake device of the present invention includes a throttle body 1 having a horizontal intake passage 2 connected to an intake port (not shown) of the engine. A pair of bearing holes 3 and 4 are formed in the peripheral wall of the throttle body 1 in a horizontal direction across the intake passage 2, and a butterfly throttle valve that opens and closes the intake passage 2 through the bearing holes 3 and 4. 5 is supported horizontally and rotatably, and seal members 6 and 7 that are in close contact with the outer peripheral surface of the valve shaft 5a are mounted in the bearing holes 3 and 4, respectively. A throttle drum 8 is fixed to one end portion of the valve shaft 5a protruding outward from the bearing hole 3. A fuel injection valve 9 capable of injecting fuel toward the intake passage 2 downstream from the throttle valve 5 is mounted on the upper wall of the throttle body 1.

  A bypass path 10 that bypasses the throttle valve 5 and is connected to the intake passage 2 is formed on the side wall of the throttle body 1 on the throttle drum 8 side. An electric motor is provided in the middle of the bypass path 10 to open and close the bypass path 10. A bypass valve 11 actuated by 12 is interposed. The bypass valve 11 can be supplied with fast idle air to the engine through the bypass 10 by being opened by the electric motor 12 according to the temperature when the engine is cold.

  A mounting surface 15 that is one step higher than the other side surfaces is formed on the side surface of the throttle body 1 opposite to the throttle drum 8, and the sensor unit 16 is mounted on the mounting surface 15.

  1 and 3 to 6, the sensor unit is configured by attaching a throttle sensor 18, an intake air temperature sensor 19, a negative pressure sensor 20, and an electronic control unit 21 to a sensor housing 17 joined to the mounting surface 15. These components will be described in turn.

  First, the sensor housing 17 integrally has three or more (three in the illustrated example) mounting bosses 25, 25... On the outer periphery thereof, and screw holes 26, 26 corresponding to these mounting bosses 25, 25. Are provided on the mounting surface 15, and the sensor housing 17 is fastened to the mounting surface 15 by screwing and tightening bolts 27 inserted into the mounting bosses 25 into the corresponding screw holes 26.

  The sensor housing 17 is provided with a rotor support hole 28 disposed coaxially with the bearing hole 4, and a rotor 18 a connected to the end of the valve shaft 5 a is rotatably supported by the rotor support hole 28. The stator 18b constituting the throttle sensor 18 is fixed to the sensor housing 17 in cooperation with the rotor 18a. Thus, the throttle sensor 18 can detect the opening of the throttle valve 5 with the rotor 18a and output an electric signal corresponding to the detected value from the stator 18b.

  A through hole 29 is formed in the throttle body 1 so as to reach the intake passage 2 upstream of the throttle valve 5 from the mounting surface 15, and a sensor holding cylinder 30 that passes through the through hole 29 and faces the intake passage 2. Is formed integrally with the sensor housing 17, and an intake air temperature sensor 19 for detecting the temperature upstream of the intake passage 2 is attached to the sensor holding cylinder 30.

  In the sensor housing 17, a sensor holding recess 31 is formed on the outer surface sufficiently separated from the mounting surface 15, and the negative pressure sensor 20 is attached to the sensor holding recess 31.

  As clearly shown in FIG. 3, a negative pressure transmission path 35 that connects the intake passage 2 downstream of the throttle valve 5 to the negative pressure sensor 20 is provided from the throttle body 1 to the sensor housing 17. The negative pressure transmission path 35 has a first passage 35a provided in the throttle body 1 so that one end thereof is close to a horizontal plane H including the axis of the intake passage 2 and opens horizontally in the upper half circumferential surface of the intake passage 2. A groove-shaped second passage 35b formed between the joint surfaces of the throttle body 1 and the sensor housing 17 so as to bend and extend upward at a substantially right angle from the other end of the first passage 35a, and the second passage. A third passage 35c formed in the sensor housing 17 extends horizontally from the upper end of 35b to reach the negative pressure sensor 20 in a crank shape, and the pulsation of the negative pressure transmitted to the third passage 35c. Is provided.

  In the illustrated example, the groove-shaped second passage 35b is formed on the mounting surface 15 of the throttle body 1, and includes a first seal groove 37 that surrounds the second passage 35b, and a second seal groove 38 that surrounds the throttle sensor 18. The third sealing groove 39 surrounding the through hole 29 is formed on the mounting surface 15 so as to communicate with each other. A series of seal members 40 are mounted in these seal grooves 37 to 39. Thus, when the second passage 35b and the first to third seal grooves 37 to 39 are formed on the mounting surface 15, when the throttle body 1 is manufactured by casting or injection molding, the second passage 35b and the seal grooves 37 to 39 are formed. 39 can be formed at the same time without error, and the manufacturing cost can be reduced, and the periphery of the second passage 35b can be reliably sealed by the seal member 40 mounted in the seal grooves 37 to 39.

  Further, the second passage 35b is formed in a polygon 42 (see FIGS. 5 and 6) in which the centers of three or more mounting bosses 25, 25... Arranged along one straight line 42a. By doing so, the fastening force of the bolts 27, 27... Can be efficiently transmitted from the mounting bosses 25, 25... To the seal member 40 around the second passage 35b, and the seal around the second passage 35b is reliably ensured. It can be carried out.

  As shown in FIGS. 1 and 4, the substrate 45 of the electronic control unit 21 is installed on the outer end of the sensor housing 17. At that time, terminals of the throttle sensor 18, the intake air temperature sensor 19 and the negative pressure sensor 20 are connected to the substrate 45. Various semiconductor elements 46 are attached on the substrate 45. Further, on one side of the sensor housing 17, a coupler 47 is formed integrally to draw out output signals of the various sensors 18 to 20 through the electronic control unit 21.

  Thus, during operation of the engine, the output signals of the throttle sensor 18, the intake air temperature sensor 19 and the negative pressure sensor 20 are used for control of the fuel injection amount, ignition timing, fast idle intake amount, and the like.

As shown in FIGS. 4 and 5, the negative pressure sensor 20 is located on the downstream side of the intake passage 2 from the valve shaft 5 a of the throttle valve 5 and above the axis of the intake passage 2 in a side view of the sensor unit 16. The negative pressure sensor 20 and the throttle sensor 18 are arranged so as to be adjacent to the throttle sensor 18, and the positions of both of the negative pressure sensor 20 and the throttle sensor 18 along the axis of the intake passage 2 overlap in the left-right direction in a side view of the sensor unit 16. Are arranged to be.

  Incidentally, since the negative pressure transmission path 35 opens in the upper half circumferential surface of the intake passage 2, it is possible to prevent the fuel droplets adhering to the inner circumferential surface of the intake passage 2 from flowing into the negative pressure transmission path 35. .

  Further, even if a foreign matter such as fuel or carbon enters the negative pressure transmission path 35 from the intake passage 2 due to the intake air blowback phenomenon of the engine, the negative pressure sensor 20 is located above the opening of the negative pressure transmission path 35 to the intake passage 2. The negative pressure transmission path 35 is formed in a crank shape having a large flow path resistance by the first to third paths 35a to 35c, so that the foreign matter can reach the negative pressure sensor 20. Therefore, the negative pressure sensor 20 can be protected from foreign matter, and its function and durability can be ensured.

  Here, a description will be given of a case where a plurality of types of throttle bodies 1 having different diameters of the intake passage 2 are manufactured by casting or injection without changing the shape of the mounting surface 15 for the sensor unit 16 in the throttle body 1. Then, as shown in FIG. 3, the large and small intake passages 2 </ b> L and 2 </ b> S having different diameters are formed so as to be in contact with each other at the opening end side of the bearing hole 4 to the intake passage 2. Thus, when the large-diameter intake passage 2L is formed, its inner peripheral surface expands so as to delete the first passage 35a of the negative pressure transmission passage 35, but the first passage 35a is Originally, it is arranged close to the horizontal plane H including the axis of the intake passage, so that the amount deleted by the inner peripheral surface of the intake passage 2 is extremely small. Therefore, the negative pressure transmission in any type of throttle body 1 The bending effect of the path 35 can be ensured, and foreign matter can be prevented from entering the negative pressure sensor 20. When the small-diameter intake passage 2S is formed, the first passage 35a is somewhat longer, so no problem occurs.

  Next, the positioning and fixing structure to the mounting surface 15 of the sensor housing 17 will be described with reference to FIGS.

  A circular positioning recess 50 that concentrically surrounds the valve shaft 5 a and a positioning hole 52 that is spaced apart from the positioning recess 50 in the radial direction are provided on the mounting surface 15 of the throttle body 1. On the other hand, the sensor housing 17 is made of synthetic resin, and includes three or more mounting bosses 25, 25,... Having three or more positioning cylinders 51 fitted into the positioning recesses 50 and positioning pins 53 fitted into the positioning holes 52. At the same time, the sensor housing 17 is formed. At this time, the positioning pin 53 is configured by integrally connecting four protruding ridges 53 a, 53 a, 53 b, 53 b in a cross-shaped cross section, and a pair of protrusions arranged on the diameter line of the positioning pin 53. The strips 53a and 53a are arranged so as to be on a straight line L connecting the center of the positioning cylinder 51 and the center of the positioning pin 53. Therefore, the other pair of protrusions 53b and 53b are orthogonal to the protrusions 53a and 53a.

  The positioning cylinder 51 and the positioning pin 53 are formed so as to be fitted in the positioning recesses 50 and the positioning holes 52 opened in the mounting surface 15.

  Thus, after the sensor unit 16 is configured, when the sensor housing 17 is attached to the attachment surface 15, first, the positioning cylinder 51 is fitted into the positioning recess 50 and the positioning pin 53 is fitted into the positioning hole 52. In this example, the fixing positions of the mounting bosses 25, 25... Are determined, and in the illustrated example, the three mounting bosses 25, 25... Are matched with the three screw holes 26, 26. Can do. Therefore, the bolts 27 inserted through the mounting bosses 25 are screwed and tightened into the screw holes 26. Thus, the sensor housing 17 is fixed to the mounting surface 15 at a fixed position.

  By the way, as described above, the positioning pin 53 is configured by integrally connecting the four projecting ridges 53a, 53a, 53b, 53b in a cross-shaped cross section, and a pair of positioning pins 53 on the diameter line. 53a, 53a are arranged on a straight line L connecting the center of the positioning cylinder 51 and the center of the positioning pin 53, so that when the sensor housing 17 is positioned, the rotation of the sensor housing 17 around the positioning cylinder 51 is The positioning pin 53 and the positioning hole 52 are fitted, and in particular, the pair of positioning protrusions 53b and 53b of the positioning pin 53 aligned in the direction orthogonal to the straight line L are fitted to the inner peripheral surface of the positioning hole 52. Is blocked. Therefore, by considering only the manufacturing error of the positioning protrusions 53b and 53, the predetermined positioning accuracy of the sensor housing 17 around the positioning cylinder 51 can be obtained, the accuracy management is simplified, and the cost is reduced. obtain.

  Further, the pair of protrusions 53a, 53a arranged on the straight line L are integrally connected to the other pair of protrusions 53b, 53b and reinforced with each other, thereby enhancing the rigidity of the positioning pin. Can do.

  Further, since the protrusions 53a, 53a, 53b, and 53b are fitted in the positioning holes 52, the sensor housing 17 is expanded by the heat generated by the engine, and the distance between the centers of the positioning cylinder 51 and the positioning pins 53 is slightly increased. Even if there is a change, the change is absorbed in the gap between the positioning pin 53 and the positioning hole 52, so that the sensor housing 17 is not distorted, and therefore the malfunction of the throttle sensor 18 due to the distortion can be prevented. it can.

  As mentioned above, although the Example of this invention was described, this invention is not limited to it, A various design change is possible in the range which does not deviate from the summary.

1 is a longitudinal plan view of an intake device for an engine according to the present invention. FIG. 2 is a sectional view taken along line 2-2 of FIG. FIG. 3 is a sectional view taken along line 3-3 in FIG. 1. FIG. 4 is a view taken in the direction of arrow 4 in FIG. 3 with the electronic control unit removed. FIG. 5 is a sectional view taken along line 5-5 of FIG. FIG. 6 is a sectional view taken along line 6-6 of FIG. FIG. 7 is an enlarged cross-sectional view taken along line 7-7 in FIG. 6. FIG. 4 is a cross-sectional view corresponding to FIG. 3 showing a conventional device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Throttle body 2 ... Intake passage 4 ... Bearing hole 5 ... Throttle valve 5a ... Valve shaft 15 ... Mounting surface 16 ... Sensor unit 17 Sensor housing 18 Throttle sensor 20 Negative pressure sensor 25 Fastening part (mounting boss)
35 ... Negative pressure transmission path 35a ... First passage 35b ... Second passage 35c ... Third passage 37 ... Seal groove (first seal groove)
42 ... Polygon 42a ... Straight line H ... Horizontal plane including the axis of the intake passage

Claims (3)

A throttle body (1) having a horizontal intake passage (2), and a valve shaft (5a) rotatably supported horizontally in a bearing hole (4) of the throttle body (1) 2) Butterfly type throttle valve (5
) And a sensor housing (17) attached to one side of the throttle body (1), the throttle sensor (18) for detecting the opening of the throttle valve (5) and the intake negative pressure of the intake passage (2) are detected. An engine intake device having a negative pressure sensor (20) attached thereto and communicating between the intake passage (2) and the negative pressure sensor (20) via a negative pressure transmission path (35). In
When the sensor unit (16) is viewed from the side, the negative pressure sensor (20) is disposed downstream of the valve shaft (5a) of the throttle valve (5) and downstream of the intake passage (2) and on the axis of the intake passage (2). The position of the negative pressure sensor (20) and the throttle sensor (18) along the axis of the intake passage (2) is arranged so as to be adjacent to the throttle sensor (18) in the upper side, as viewed from the side of the sensor unit (16). The negative pressure transmission path (35) is disposed so as to overlap with each other in the left-right direction, and the upper half circumference of the intake passage (2) is arranged so that one end thereof is close to the horizontal plane (H) including the axis of the intake passage (2). A first passage (35a) that opens to the surface, and a joint surface between the throttle body (1) and the sensor housing (17) so as to bend and extend upward at a substantially right angle from the other end of the first passage (35a). Groove-shaped second passage (35b) formed , De a third passage is formed in the second passage (35b) upper first passage (35a) and extends to the opposite side to the reach the negative pressure sensor (20) from the sensor housing (17) (35c) Engine intake system, characterized by a crank configuration. The engine intake system according to claim 1,
The second passage (35b) and a seal groove (37) that surrounds the second passage (35b) and is fitted with a seal member (40) are formed on the joint surface (15) on the throttle body (1) side. An intake device for an engine, characterized by The engine intake system according to claim 1 or 2,
The second passage (35b) is formed by sequentially connecting the centers of three or more fastening portions (25, 25...) That fasten the throttle body (1) and the sensor housing (17) with straight lines (42a). An intake system for an engine characterized by being arranged along one straight line (42a) in a square (42).

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