JP4217240B2 - Engine intake system - Google Patents

Description

  The present invention relates to an engine intake device, and more particularly to an improvement of an engine intake device in which a bypass path that bypasses a throttle valve is connected to an intake passage of a throttle body.

Such an intake device for an engine is already known as disclosed in Patent Document 1.
Japanese Utility Model Publication No. 6-45654

In the conventional intake system of such an engine, the entire bypass passage is formed in the throttle body, so that the throttle body requires complicated processing and the productivity is low.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an intake device for an engine that can easily form a bypass passage and has high productivity.

In order to achieve the above object, the present invention provides an intake system for an engine in which a bypass passage that bypasses a throttle valve is connected to an intake passage of a throttle body, and an upstream portion and a downstream portion of the intake passage sandwiching the throttle valve. A bypass inlet hole and a bypass outlet hole formed in the throttle body so as to open respectively, and a groove shape is formed between the throttle body and a device block joined to the throttle body, and both ends of the bypass inlet hole and the bypass are formed. The bypass intermediate section connected to the outlet hole constitutes the bypass passage, and a boost negative pressure extraction hole is provided from the throttle body to the device block to extract the boost negative pressure in the intake passage downstream from the throttle valve. A pressure extraction hole is formed in the throttle body and the downstream Is composed of a negative pressure introducing hole communicating with the joint surface of the throttle body and the device block, and a negative pressure guiding hole provided in the device block so as to communicate with the negative pressure introducing hole. A boost negative pressure sensor that faces the sensing portion at the end is attached to the device block, and the negative pressure introduction hole is located upstream of the bypass outlet hole in the radial direction of the intake passage when viewed in the axial direction of the intake passage. The first feature is that it is arranged on the axial center side with respect to the bypass inlet hole .

The present invention, in addition to the first feature, the device blocks, the second feature in that attach the throttle sensor for detecting an opening degree of the throttle valve.

The present invention, in addition to the first or second feature, the device blocks, the third feature in that attach the intake air temperature sensor for detecting the intake air temperature.

  Furthermore, in addition to any of the first to third features, the present invention has a fourth feature that the device block is made of a synthetic resin.

  According to the first aspect of the present invention, the bypass passage is divided into a bypass inlet hole and a bypass outlet hole formed in the throttle body, and a bypass intermediate portion formed in a groove shape between the throttle body and the device block. Therefore, this bypass path can be easily formed, which can contribute to the improvement of the productivity of the intake device.

  Further, the boost negative pressure extraction hole is divided into a negative pressure introduction hole provided in the throttle body and a negative pressure induction hole provided in the device block, so that the boost negative pressure extraction hole can be easily formed. By attaching a boost negative pressure sensor that faces the sensing part to the end of this negative pressure induction hole, the device block / boost negative pressure sensor assembly can be constructed, and the intake device can be made more compact and produced. It is possible to further improve the sex.

  According to the second feature of the present invention, a device block / boost negative pressure sensor / throttle sensor assembly can be constructed, and the function of the intake device can be enhanced while achieving compactness and improved productivity. it can.

  According to the third aspect of the present invention, a device block / boost negative pressure sensor / intake air temperature sensor assembly can be constructed, and the function of the intake device is enhanced, while attaining compactness and productivity improvement. Can do.

  According to the fourth feature of the present invention, the groove-shaped bypass intermediate portion can be easily formed simultaneously with the molding of the device block with the synthetic resin, which can contribute to the further improvement of the productivity of the intake device.

  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 side view of an intake system for an engine according to the present invention, FIG. 2 is a sectional view taken along line 2-2 of FIG. 1, FIG. 3 is a sectional view taken along line 3-3 of FIG. 5 is a sectional view taken along line 5-5 in FIG. 4, FIG. 6 is a sectional view taken along line 6-6 in FIG. 3, FIG. 7 is a sectional view taken along line 7-7 in FIG. FIG. 9 is a sectional view taken along line -8, and FIG. 9 is an exploded perspective view of the intake device.

  First, in FIGS. 1 and 2, the throttle body 1 has an intake passage 2 extending in the horizontal direction. The inlet of the intake passage 2 has a funnel shape and is connected to an air cleaner (not shown), and the outlet side is connected to an intake port of an engine (not shown). A pair of bosses 3, 3 ′ having shaft holes 4, 4 ′ perpendicular to the axis of the intake passage 2 are formed on both sides of the middle part of the throttle body 1, and are rotated by these shaft holes 4, 4 ′. A butterfly throttle valve 5 that opens and closes the intake passage 2 is fixed to a valve shaft 6 that is freely supported. A throttle drum 7 for connecting an operation wire 9 connected to a throttle operation member (not shown) is fixed to one end of the valve shaft 6, and the throttle drum 7 is used to urge the throttle valve 5 in the closing direction. A return spring 24 is connected. A rotor 8 a of a throttle sensor 8 that detects the opening degree of the throttle valve 5 is fixed to the other end of the valve shaft 6. Reference numeral 44 denotes an outer wire support bracket that guides the operation wire 9 and is screwed to the throttle body 1.

  As shown in FIGS. 2 and 9, a housing 10 is integrally formed on one side of the throttle body 1. The other boss 3 ′ protrudes on the bottom surface 10 a of the housing 10, and the shaft hole 4 ′ and the bottom surface 10 a of the boss 3 ′ are arranged so as to be orthogonal to each other. A bottom surface 10a of the housing 10 is an attachment surface, and a device block 11 accommodated in the housing 10 is fixed to the attachment surface 10a by a plurality of bolts 12 and 12. Further, the device block 11 is integrally formed with a flange portion 11c that closes the open surface of the housing 10, and a sealing member 13 that makes the inside of the housing 10 watertight is interposed between the joint surface of the flange portion 11c and the housing 10. Is done.

  A rotor housing hole 14 for housing the other boss 3 'and the rotor 8a is formed on the surface of the device block 11 facing the mounting surface 10a.

  As shown in FIGS. 3 to 5, 7 and 8, a bypass path 15 is formed from the throttle body 1 to the device block 11. The bypass passage 15 includes a bypass inlet hole 15i formed in the throttle body 1 so as to communicate between the intake passage 2 and the mounting surface 10a on the upstream side of the throttle valve 5, and the intake passage on the downstream side of the throttle valve 5. 2 and the bypass outlet hole 15o formed in the throttle body 1 so as to communicate with the mounting surface 10a, and a bypass intermediate portion provided in the device block 11 and communicating between the bypass inlet hole 15i and the bypass outlet hole 15o. 15m. Therefore, the bypass passage 15 is connected to the intake passage 2 so as to bypass the throttle valve 5.

  As clearly shown in FIG. 5, the bypass intermediate portion 15m of the device block 11 is formed on the inner surface of the device block 11 facing the mounting surface 10a so as to communicate with the bypass inlet hole 15i and the bypass outlet hole 15o, respectively. The upstream groove portion 16 and the downstream groove portion 17, a through hole 18 connected to one end of the upstream groove portion 16, a valve guide hole 19 rising upward from the through hole 18, and an intermediate portion of the valve guide hole 19 as the other end of the downstream groove portion 17 It is comprised with the measurement hole 20 connected to a part. At that time, the upstream groove portion 16 is disposed so as to be inclined in the vertical direction, the bypass inlet hole 15i is opened at the lower end portion thereof (see FIG. 7), and the through hole 18 is opened at the upper end portion. Further, the downstream groove portion 17 is longer than the upstream groove portion 16 and extends substantially horizontally from the valve guide hole 19 side and is bent downward from the middle, and a bypass outlet hole 15o is opened at a lower end portion thereof. Thus, the measuring hole 20 is disposed above the bypass inlet hole 15 i and the outlet hole 15 o and on the inlet side of the intake passage 2. Accordingly, even when the intake passage 2 is arranged horizontally as shown in the drawing, or when the intake passage 2 inlet is directed upward, the measuring hole 20 occupies the position above the bypass inlet hole 15i and the bypass outlet hole 15o. It will be. That is, the bypass path 15 always has a shape that descends toward the bypass inlet hole 15i and the bypass outlet hole 15o with the measuring hole 20 as a vertex.

  Further, as clearly shown in FIGS. 3 and 8, a boost negative pressure extraction hole 21 is provided from the throttle body 1 to the device block 11 to extract the intake negative pressure of the intake passage 2 downstream from the throttle valve 5, that is, the boost negative pressure. . The boost negative pressure extraction hole 21 includes a negative pressure introduction hole 21a formed in the throttle body 1 so as to communicate between the intake passage 2 and the mounting surface 10a on the downstream side of the throttle valve 5, and the negative pressure introduction hole 21a. And a negative pressure guide hole 21b provided in the device block 11 so as to extend so as to bend upward, and a boost negative pressure sensor 23 that faces the sensing portion at the upper end of the negative pressure guide hole 21b is provided in the device block. 11 is attached.

In the above, the bypass inlet hole 15i, the bypass outlet hole 15o, and the negative pressure introducing hole 21a are all arranged in parallel with the shaft hole 4 '. As clearly shown in FIG. 5, the negative pressure introduction hole 21 a is upstream of the bypass outlet hole 15 o when viewed in the axial direction of the intake passage 2 and from the bypass inlet hole 15 i when viewed in the radial direction of the intake passage 2. Is also arranged on the axial side.

  Between the attachment surface 10a of the housing 10 and the inner surface of the device block 11 that are joined together, a seal member 22 that surrounds each part of the bypass passage 15 and the boost negative pressure extraction hole 21 is interposed.

  3 to 6, a piston-type bypass valve 25 is slidably fitted in the valve guide hole 19. The bypass valve 25 has a hollow portion 25a opened to the side of the through hole 18 on the lower surface, and the air flow rate in the bypass passage 15 is reduced on the side wall of the hollow portion 25a in cooperation with the measuring hole 20. A metering groove 26 to be controlled is provided. The measuring groove 26 includes a wide portion 26 a that opens to the lower end of the bypass valve 25, and a narrow portion 26 b that continues to the upper end of the wide portion 26 a, and the upper portion of the wide portion 26 a faces the measuring hole 20. It is possible to move up and down between the degree position and the low opening position where only the narrow portion 26 b faces the measuring hole 20. At this time, a positioning projection 27 that engages with the wide portion 26 a is formed on the device block 11 to prevent the bypass valve 25 from rotating.

  Above the bypass valve 25, a step motor 28 arranged coaxially with the bypass valve 25 is installed in the device block 11. The rotor 29 of the step motor 28 is integrally provided with a screw shaft 30 extending downward, and the screw shaft 30 is screwed into a screw hole 31 formed at the center of the bypass valve 25.

  Further, as shown in FIG. 3, the device block 11 is formed with an attachment recess 32 adjacent to the rotor housing hole 14 and the upstream groove 16 with the thin partition walls 11 a and 11 b interposed therebetween, and is inserted into the attachment recess 32. The sensor holder 35 holds a pickup coil 8b facing the rotor 8a in the rotor housing hole 14 across the partition wall 11a, and an intake air temperature sensor 34 for detecting the temperature in the upstream groove portion 16 through the partition wall 11b. The pickup coil 8b constitutes a throttle sensor 8 that electrically detects the opening of the throttle valve 5 in cooperation with the rotor 8a.

  The throttle valve opening θth, the boost negative pressure Pb, the intake air temperature Ta detected by the throttle sensor 8, the boost negative pressure sensor 23, and the intake air temperature sensor 34, and the engine temperature Te detected by an engine coolant temperature sensor (not shown). Such information regarding engine operating conditions is input to the electronic control unit 36 connected to the step motor 28.

  The sensor holder 35 is integrally provided with first and second pressing arms 35a and 35b that press and hold the step motor 28 and the boost negative pressure sensor 23 against the housing 10 from above. The two pressing arms 35a and 35b are formed with first and second locking claws 38a and 38b that are elastically engaged with the engaging recess 37a and the engaging hole 37b of the device block 11, respectively. Therefore, the sensor holder 35 is detachably attached to the device block 11 by the engagement of the first and second locking claws 38a, 38b with the engagement recess 37a and the engagement hole 37b, whereby the step motor 28, boost The negative pressure sensor 23, the pickup coil 8b, and the intake air temperature sensor 34 are held in the device block 11 all at once.

  The device block 11 and the sensor holder 35 are integrally formed with projecting pieces 40 and 41 penetrating through the bottom of the housing 10 while cooperating to define the wiring guiding path 39, respectively, the step motor 28, the pickup coil 8b, Various lead wires 42, 42... Connected to the boost negative pressure sensor 23 and the intake air temperature sensor 34 are drawn out of the housing 10 through the wiring guiding path 39.

  As described above, the device block / bypass valve / sensor assembly 43 is configured by attaching the bypass valve 25, the step motor 28, the pickup coil 8b, the boost negative pressure sensor 23, and the intake air temperature sensor 34 to the device block 11. .

  Next, the operation of this embodiment will be described.

  When the throttle valve 5 is fully closed, the electronic control unit 36 is based on the information about the engine operating conditions such as the throttle valve opening θth, the boost negative pressure Pb, the intake air temperature Ta, and the engine temperature Te that are input as described above. In order to obtain the optimum opening of the bypass valve 25 corresponding to the engine operating conditions such as engine start, fast idling, normal idling, engine braking, etc., the energization amount to the step motor 28 is calculated and the energization is performed. , And the rotor 29 is rotated forward or backward together with the screw shaft 30. When the screw shaft 30 rotates or reversely rotates, the non-rotatable bypass valve 25 moves up and down along the valve guide hole 19.

  Thus, when the bypass valve 25 rises and occupies a high opening position, the wide portion 26a of the measuring groove 26 of the bypass valve 25 is exposed to the measuring hole 20 of the bypass path 15, and therefore flows through the bypass path 15. The amount of intake air taken into the engine is controlled by a relatively large amount by the opening area of the wide portion 26a to the measuring hole 20, and can cope with engine start-up and fast ring operation. When the bypass valve 25 is lowered and occupies the low opening position, the narrow portion 26b of the measuring groove 26 of the bypass valve 25 is exposed to the measuring hole 20, so that the intake air flowing through the bypass passage 15 is reduced to the narrow portion. It is controlled to a relatively small amount by the opening area of the measurement hole 20 of 26b, and can cope with normal idling operation and engine braking of the engine.

  If the throttle valve 5 is opened, an amount of intake air corresponding to the opening degree is supplied to the engine through the intake passage 2, and the engine moves to the output operation range.

  In such an intake device, a bypass valve 25, a step motor 28, a pickup coil 8b, a boost negative pressure sensor 23, and an intake air temperature sensor 34 are attached to a device block 11 that is detachably attached to a housing 10 integrated with the throttle body 1. As a result, the device block / bypass valve / sensor assembly 43 is formed, so that the machining of the throttle body 1 is reduced and the device block / bypass valve / sensor assembly 43 is manufactured in parallel with the throttle body 1. Can improve productivity. In addition, by removing the device block 11 from the throttle body 1, maintenance of the bypass path 15, the bypass valve 25, the throttle sensor 8 and the like can be easily performed. In addition, by changing the specifications of the bypass valve 25, the step motor 28, and the various sensors 8, 23, 34 in the device block 11, an intake device for an engine with different specifications can be easily provided while using the same throttle body 1. The mass productivity of the throttle body 1 can be increased.

  The bypass passage 15 is formed in a bypass inlet hole 15i and a bypass outlet hole 15o provided in the throttle body 1 and a synthetic resin device block 11 and is connected to the bypass inlet hole 15i and the bypass outlet hole 15o at both ends. The bypass inlet hole 15i, the bypass outlet hole 15o, and the negative pressure introducing hole 21a are arranged in parallel with the shaft hole 4 'for supporting the valve shaft 6 of the throttle valve 5, so that the shaft 15 The hole 4 ', the bypass inlet hole 15i, the bypass outlet hole 15o, and the negative pressure introducing hole 21a can be formed at once from the mounting surface 10a side by a multi-axis drilling machine or by a plurality of parallel core pins during casting. In addition, since the bypass intermediate portion 15m can be formed simultaneously with the molding of the synthetic resin device block 11, the manufacturing time can be greatly shortened. Furthermore, the weight of the entire intake device can be reduced by employing the lightweight synthetic resin device block 11.

Further, in the bypass passage 15, the measuring hole 20 is arranged above the bypass inlet hole 15 i and the bypass outlet hole 15 o and on the inlet side of the intake passage 2. Even when the throttle body 1 is used as the arranged side draft type, as well as when the throttle body 1 is used as a down draft type with the intake passage 2 inlet facing upward, the measuring hole 20 has the bypass inlet hole 15i and the bypass outlet. Occupying a position above the hole 15o, the bypass passage 15 always descends toward the bypass inlet hole 15i and the bypass outlet hole 15o with the measuring hole 20 at the apex, so that the inlet side of the intake passage 2 during engine operation. oil in supplied by gas or EGR gas from a fluidized foreign matter such as moisture from entering the bypass passage 15, which foreign matter After the stop of the operation of the engine, the bypass inlet hole flows down naturally to 15i and the bypass outlet aperture 15o side, continue to flow out into the intake passage 2 does not become the orゝand attached to the periphery of the metering hole 20. Therefore, malfunction of the bypass valve 25 and deviation of the opening due to freezing or accumulation of foreign matters at the periphery of the measuring hole 20 can be avoided in advance.

  In addition, since the intake device has versatility as described above, not only the degree of freedom of layout can be increased, but also mass production can be improved and cost can be reduced.

  The device block 11 coupled to the mounting surface 10a of the housing 10 with bolts 12 and 12 is integrally formed with the flange portion 11c that closes the open surface of the housing 10, so that the device block 11 is attached to the mounting surface 10a at the same time. The open surface of the housing 10 can be closed, and a dedicated lid for the closing is not necessary, which can contribute to simplification of the configuration.

  The present invention is not limited to the above embodiments, and various design changes can be made without departing from the scope of the invention.

The side view of the intake device of the engine which concerns on this 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. 1. FIG. 4 is a sectional view taken along line 4-4 of FIG. 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 a cross-sectional view taken along line 7-7 in FIG. 3. FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. 3. The disassembled perspective view of the same intake device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Throttle body 2 ... Intake passage 5 ... Throttle valve 8 ... Throttle sensor 11 ... Device block 15 ... Bypass path 15i ... Bypass inlet hole 15o ... Bypass outlet hole 15m ... Bypass intermediate part 23 ... Boost negative pressure sensor 34 ... Intake air temperature sensor

Claims (4)

In an intake system for an engine in which a bypass passage (15) bypassing the throttle valve (5) is connected to the intake passage (2) of the throttle body (1),
A bypass inlet hole (15i) and a bypass outlet hole (15o) formed in the throttle body (1) so as to open to an upstream portion and a downstream portion of the intake passage (2) with the throttle valve (5) interposed therebetween, , A bypass intermediate portion formed in a groove shape between the throttle body (1) and the device block (11) joined thereto and connecting both ends to the bypass inlet hole (15i) and the bypass outlet hole (15o) ( 15m) constitutes the bypass passage (15), and the boost negative pressure is taken out from the throttle body (1) to the device block (11) to extract the boost negative pressure in the intake passage (2) downstream from the throttle valve (5). A pressure take-out hole (21) is provided, and the boost negative pressure take-out hole (21) is connected to the downstream portion of the throttle body (1) and the device. A negative pressure introduction hole (21a) communicating with the joint surface of the block (11) and a negative pressure induction hole (21b) provided in the device block (11) so as to communicate with the negative pressure introduction hole (21a) The boost negative pressure sensor (23) is configured to be attached to the device block (11), and the negative pressure introduction hole (21a) is connected to the intake passage (21a). 2) that is disposed upstream of the bypass outlet hole (15o) as viewed in the axial direction of 2) and closer to the axial center than of the bypass inlet hole (15i) when viewed in the radial direction of the intake passage (2). A feature of the engine intake system. The engine intake system according to claim 1,
Wherein the device block (11), characterized in that said attach the throttle valve throttle sensor (8) for detecting the degree of opening of (5), an intake device for an engine. The engine intake system according to claim 1 or 2,
Wherein the device block (11), characterized in that attach the intake air temperature sensor for detecting the intake air temperature (34), an intake device for an engine. The engine intake device according to any one of claims 1 to 3,
An intake device for an engine, wherein the device block (11) is made of synthetic resin.

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