JP2006097695A - Throttle valve device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a throttle body by resin while preventing freezing of a throttle valve in the winter. <P>SOLUTION: The throttle body 11 is formed to have a double pipe structure arranging an internal pipe 16 in an external pipe 15 concentrically by forming it by resin integrally, and the throttle valve 18 is incorporated into the internal pipe 16. A space between the external pipe 15 and the internal pipe 16 is partitioned by a bulkhead 19 over the whole periphery. A space 20 on the upstream side is formed as a daming-up recessed part 20 for daming up water from the upstream side, and a space 21 on the downstream side faces a surge tank 13 through a clearance 29 to damp up water condensed in the surge tank 13 by the space 21 on the downstream side. A bypass air passage 27 allowing air to flow in a path from the space 20 on the upstream side, inlet 22 for air flow, a space in a surrounding wall 24, an outlet 23 for air flow to the space 21 on the downstream side in this order is formed, and an ISC valve 28 is provided in this bypass air passage 27. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a throttle valve device for an internal combustion engine having a function of preventing freezing of the throttle valve due to moisture transmitted from the upstream side of the throttle valve to the inner peripheral surface of the intake pipe in winter.

  As shown in FIG. 7, the conventional general throttle valve freeze prevention structure is configured such that moisture transmitted from the upstream side of the throttle valve 1 to the inner peripheral surface of the intake pipe 2 in the winter is blocked by the throttle valve 1. In order to prevent the engine from being frozen, a hot water passage 4 through which the engine cooling hot water is passed is formed in the throttle body 3, and the engine cooling hot water is introduced into the hot water passage 4 to warm the throttle body 3 and the throttle valve 3. To prevent freezing.

  However, in the above conventional configuration, it is necessary to connect the inlet pipe 5 of the hot water passage 4 of the throttle body 3 and the engine cooling system with a pipe, a hose or the like, and it is troublesome to assemble in an engine room with little free space. In addition, there is a drawback that the cost of parts such as pipes and hoses is high. Moreover, since the engine cooling water drops in temperature due to heat dissipation as the standing time after the engine is stopped becomes longer, there is a disadvantage that the prevention of freezing by the engine cooling water does not function at all for a vehicle left for a long time.

  Further, in recent years, it has been considered that the throttle body 3 is made of resin for the purpose of reducing the cost of the throttle body 3 and integrating it with other parts. However, since the resin has a low thermal conductivity, if the throttle body 3 is made of resin, it is difficult to warm the throttle body 3 above the freezing point by simply introducing engine coolant in a cold region. Can not be prevented from freezing.

  Japanese Utility Model Laid-Open No. 3-17156 describes a structure for preventing the throttle valve from freezing without introducing engine coolant into the throttle body, which is connected to the downstream side of the throttle body. In order to prevent the throttle valve from freezing due to moisture condensed in the surge tank (common chamber), the surge tank has a step that lowers the surge tank side at the connecting part between the flange on the downstream side of the throttle body and the surge tank. This prevents moisture condensed inside from flowing into the throttle body. This anti-freezing structure copes with the fact that the moisture that condenses in the surge tank increases in the case of an engine with EGR, but the inner peripheral surface of the intake pipe is formed along the air flow from the upstream side of the throttle valve. It has no effect on the water that is transmitted. In a normal engine, moisture entering from the upstream side of the throttle valve becomes a problem, and how to prevent freezing by this moisture has become an important technical issue in recent years.

  The present invention has been made in consideration of such circumstances, and the object thereof is to prevent freezing of the throttle valve due to moisture from the upstream side without introducing engine cooling water into the throttle body. An object of the present invention is to provide a throttle valve device for an internal combustion engine that can meet the requirements of improved assembly, reduced number of parts, and resin.

  In order to achieve the above object, a throttle valve device for an internal combustion engine according to claim 1 of the present invention is provided with a throttle valve for controlling an intake air amount in a tubular throttle body so as to be opened and closed. Forming a U-shaped blocking recess for blocking moisture transmitted from the upstream side at the lower part where moisture is transmitted from the upstream side of the throttle valve to the inner peripheral surface of the intake pipe at least in the circumferential part, The blocking recess has a structure that does not have any other communication path connected to the lower part where the blocked water is accumulated, and the opening of the blocking recess is positioned upstream of the throttle valve. The opening is made to face from the downstream side to the upstream side of the throttle valve.

  In this configuration, moisture transmitted from the upstream side of the throttle valve to the inner peripheral surface of the intake pipe is blocked by a U-shaped blocking recess formed at least at the lower portion of the inner peripheral portion of the throttle body, It can accumulate against the flow and prevents the moisture from reaching the throttle valve. For this reason, even if the engine cooling water is not introduced into the throttle body in winter, the water that is blocked and stored in the blocking recess only freezes there, and the throttle valve is prevented from freezing.

  According to a second aspect of the present invention, the throttle body is integrally formed of resin. As described above, according to the present invention, it is not necessary to warm the throttle body with the engine cooling water in order to prevent the throttle valve from freezing by blocking the moisture entering from the upstream side of the throttle valve and blocking the moisture by the blocking recess. Even if the throttle body is integrally formed of a resin having a low thermal conductivity, the antifreezing performance is not impaired.

  As is apparent from the above description, according to the configuration of claim 1 of the present invention, a blocking recess is formed at least at the lower portion of the inner peripheral portion of the throttle body, and is transmitted to the inner peripheral surface of the intake pipe from the upstream side of the throttle valve. Since the incoming moisture is blocked by the blocking recess, it is possible to prevent the throttle valve from freezing due to moisture from the upstream side without introducing engine cooling water into the throttle body. It is not necessary to connect the cooling system with a pipe or a hose, so that the assembly in the engine room can be improved, and the number of parts and the part cost can be reduced. In addition, the integral molding of the throttle body with resin can be realized without impairing the anti-freezing performance, and the demand for weight reduction and cost reduction of the throttle body can be satisfied.

  Further, in claim 2, by integrally molding the throttle body with resin, it is possible to reduce the weight of the throttle body and reduce the cost, and also to integrally mold with other parts, further reducing the number of parts and assembling. Can also be improved.

  Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. The throttle body 11 is fixed by a band (not shown) or the like downstream of the intake pipe 12 made of a rubber duct, and an air cleaner (not shown) is attached to the upstream part of the intake pipe 12. On the other hand, a surge tank 13 is connected to the downstream side of the throttle body 11 with bolts (not shown) or the like with a sealing material 10 interposed therebetween, and from this surge tank 13 to each cylinder of an engine (not shown) through an intake manifold 14. Intake air is introduced.

  The throttle body 11 is formed in a double pipe structure in which an inner pipe 16 slightly shorter than the outer pipe 15 is concentrically arranged in the outer pipe 15 by integral molding of heat-resistant resin, and an intake passage is formed by the inner pipe 16. A throttle valve 18 is incorporated through a shaft 17 at the center of the lever. Furthermore, the space between the outer tube 15 and the inner tube 16 is partitioned by a partition wall 19 at the substantially center thereof, and the upstream space 20 of the partition wall 19 absorbs moisture transmitted through the inner peripheral surface of the intake pipe 12. It is a blocking recess 20 for blocking. The opening of the blocking recess 20 is positioned on the upstream side of the throttle valve 18 so that the opening of the blocking recess 20 faces the upstream side of the throttle valve 18. The blocking recess 20 has a configuration that does not have any other communication path connected to the lower part where the blocked water accumulates (see FIG. 1). The upstream end surface portions of the outer tube 15 and the inner tube 16 are formed in a round shape (rounded shape) in order to reduce the ventilation resistance of the intake air, and the upstream end surface portion of the inner tube 16 is the outer tube. 15 is shifted downstream from the upstream end face. As a result, the space of the blocking recess 20 is saved, and the inner tube 16 is prevented from projecting to the upstream portion more than necessary, thereby saving the material.

  Further, in the upstream space 20 (blocking recess) and the downstream space 21 partitioned by the partition wall 19 between the outer tube 15 and the inner tube 16, the air inlet 22 is formed in the upper wall portion of the outer tube 15. An air outlet 23 is formed, and a surrounding wall 24 is integrally formed on the outer periphery of the outer tube 15 so as to surround the air inlet 22 and the air outlet 23. Then, the upstream space 20 (blocking recess) → air flow is obtained by fitting and mounting the step motor 26 with the sealing material 25 sandwiched between the upper surface opening of the surrounding wall 24 and closing the upper surface opening of the surrounding wall 24. A bypass air passage 27 through which air flows is formed in the path of the inlet 22 → the space in the surrounding wall 24 → the air outlet 23 → the downstream space 21.

  In the bypass air passage 27, an idle speed control valve (hereinafter abbreviated as “ISC valve”) 28 driven by a step motor 26 is provided as a bypass air flow rate adjusting means at a position facing the air outlet 23. By performing feedback control of the opening of the ISC valve 28 (that is, the gap between the ISC valve 28 and the air outlet 23) by the step motor 26 during idle operation, the idle speed is stabilized. The upper edge portion of the air outlet 23 is formed in a tapered shape corresponding to the shape of the ISC valve 28 and functions as a valve seat.

  On the other hand, the opening area of the upstream flange portion 13 a of the surge tank 13 is set to be substantially the same as the opening area of the inner pipe 16 that is the air passage area in the throttle body 11. The airflow resistance is reduced. Further, since the end surface 13aa on the ISC valve 28 side of the flange portion 13a is provided so as to close the air outlet 23, dirt from the downstream side does not adversely affect the ISC valve 28. The gravity direction end surface 13ab of the flange portion 13a only needs to be configured to accumulate moisture in a downstream space 21 described later, and the flange portion prevents the moisture from the downstream side from jumping over the gap 29 and adhering to the throttle valve 18. The end surface 13ab in the gravity direction of 13a may be formed below the position shown in FIG.

  A gap 29 is formed over the entire circumference between the inner pipe 16 and the end face of the upstream flange portion 13a of the surge tank 13, and the bypass air that has passed through the bypass air passage 27 enters the surge tank 13 from the gap 29. While flowing in, moisture condensed in the surge tank 13 flows into the downstream space 21 in the throttle body 11 from the gap 29 and is stored.

  As shown in FIGS. 2 and 3, an intake pipe pressure sensor 30 made of a semiconductor pressure sensor is attached to the left side of the outer periphery of the throttle body 11, and the outer peripheral wall (outside wall) of the downstream space 21 in the throttle body 11 is attached. The pressure detection part 32 (pressure introduction pipe part) of the intake pipe pressure sensor 30 is introduced into the downstream space 21 from the sensor introduction hole 31 formed in the pipe 15), and the pressure detection part 32 and the sensor introduction hole 31 are connected to each other. The gap is sealed with a sealing material 33. Furthermore, a small-diameter purge hole 34 is formed in the partition wall 19 that partitions the upstream space 20 (blocking recess) and the downstream space 21 at a position facing the pressure detection portion 32 of the intake pipe pressure sensor 30. The air flow that has passed through the purge hole 34 flows toward the pressure detection unit 32.

  As shown in FIG. 2, a throttle lever 35 connected to the shaft 17 of the throttle valve 18 is provided on the right side of the outer periphery of the throttle body 11, and the throttle lever 35 and an accelerator pedal (not shown) are connected to each other. The space is connected by an accelerator wire (not shown). Thereby, the throttle lever 35 is rotated according to the depression amount of the accelerator pedal, and the throttle valve 18 is rotated integrally therewith.

  In the first embodiment described above, the throttle body 11 has a double-pipe structure, and the blocking recess 20 (upstream space) is formed toward the upstream side over the entire circumference of the throttle body 11. Therefore, even if moisture transmitted from the upstream side of the throttle valve 18 to the inner peripheral surface of the intake pipe 12 reaches the throttle body 11, the moisture is surely blocked by the blocking recess 20, and the throttle valve Reaching 18 is prevented. Moreover, since the opening of the downstream space 21 partitioned by the partition wall 19 in the throttle body 11 faces the surge tank 13 on the downstream side of the throttle valve 18 through the gap 29, the moisture condensed in the surge tank 13 Even if the water reaches the throttle body 11 side, the moisture flows into the downstream space 21 from the gap 29 and is stored, and is prevented from reaching the throttle valve 18. For this reason, even if the engine cooling water is not introduced into the throttle body 11 in winter as in the prior art, the water blocked in the blocking recess 20 (upstream space) and the downstream space 21 is only frozen there. Thus, the throttle valve 18 can be prevented from freezing. Moreover, there is no need to introduce engine cooling water into the throttle body 11, so there is no need to connect the throttle body 11 and the engine cooling system with pipes or hoses, and the assembly into the engine room is extremely simple. At the same time, the number of parts and the part cost can be reduced.

  Furthermore, in the above embodiment, the bypass air passage 27 is formed between the outer tube 15 and the inner tube 16 so that the blocking recess 20 (upstream space) partitioned by the partition wall 19 communicates with the downstream space 21. Since the ISC valve 28 is provided by using the bypass air passage 27, both the blocking recess 20 and the bypass air passage 27 of the ISC valve 28 are utilized by using the double pipe structure of the throttle body 11. Thus, it is easy to integrally mold them, and the requirements for simplification of the mold configuration and reduction of molding cost can be satisfied.

  In the above embodiment, the ISC valve 28 is provided in the bypass air passage 27, but a bypass screw may be provided to face the air inlet 22. This bypass screw is used when the idling speed is initially set at the factory, or when the intake amount (ventilation area) of the throttle valve 18 in the fully closed state decreases with time due to dirt adhering to the intake air. Used to manually adjust it. Both the ISC valve 28 and the bypass screw may be provided, or only one of them may be provided.

  In the above embodiment, since the pressure detector 32 of the intake pipe pressure sensor 30 is arranged in the downstream space 21 in the throttle body 11, the downstream space 21 can also be used as an arrangement space for the pressure detector 32. In addition, it is not necessary to separately provide an arrangement space for the pressure detection unit 32, the processing cost can be reduced, and the intake pipe pressure sensor 30 can be easily assembled.

  Moreover, in the above-described embodiment, only the purge hole 34 is formed at the position facing the pressure detection unit 32 in the partition wall 19, and the air flow is continuously applied to the pressure detection unit 32 to prevent foreign matter from adhering to the pressure detection unit 32. It is possible to prevent the deterioration of the detection accuracy of the intake pipe pressure due to the adhesion of foreign matter.

  Furthermore, as described above, in the above-described embodiment, moisture is held in the throttle body 11 by the blocking recess 20 (upstream space) and the downstream space 21 that are partitioned and formed in the throttle body 11 having a double-pipe structure. By blocking, it is not necessary to warm the throttle body 11 with engine cooling water in order to prevent the throttle valve 18 from freezing. For this reason, high thermal conductivity is not required as a physical property required for the forming material of the throttle body 11, and even if the throttle body 11 is integrally formed with a resin having low thermal conductivity, there is no loss of freezing prevention performance. Excellent anti-freezing performance can be secured. In addition, the cost of the throttle body 11 can be reduced and the weight can be reduced by using resin, and further, the throttle body 11, the intake pipe 12, and the surge tank 13 can be integrated with resin.

  In the first embodiment described above, the throttle body 11 has a double-pipe structure, but it is not always necessary to have a double-pipe structure in order to achieve the intended object of the present invention. For example, as shown in FIG. As in the second embodiment of the present invention, the blocking recess 42 is formed only in the lower portion of the throttle body 41 by integral molding of resin, and the opening of the blocking recess 42 is exposed to the upstream side of the throttle valve 18. It is good also as a structure which was not.

  In the second embodiment, the bypass air passage 27 and the downstream space 21 provided in the first embodiment are not provided, and only the blocking recess 42 is provided. Even in this configuration, moisture from the upstream side can be blocked by the blocking recess 42 formed in the lower portion of the throttle body 41, and the intended object of the present invention can be achieved.

  Further, in the third embodiment of the present invention shown in FIG. 5, a blocking recess 44 is formed on the entire circumference of the throttle body 43 by integral molding of resin, and the opening of the blocking recess 44 is formed in the throttle valve 18. It is configured to face the upstream side. Even in the third embodiment, there is no bypass air passage 27 or downstream space 21 provided in the first embodiment.

  On the other hand, in the fourth embodiment of the present invention shown in FIG. 6, as in the first embodiment, the throttle body 45 is concentrically formed with the inner tube 47 shorter than that in the outer tube 46 by integral molding of resin. The space between the outer tube 46 and the inner tube 47 is partitioned by a partition wall 48 around the entire circumference by a partition wall 48 to form a blocking recess 49 (upstream space) and a downstream space. 50 is formed. A feature of the fourth embodiment is that the inner peripheral surface of the inner pipe 47 is formed in a tapered shape that expands from the central portion toward the upstream side / downstream side. It is harder to reach. Even in the fourth embodiment, the bypass air passage 27 provided in the first embodiment is not provided.

  In each of the embodiments described above, the throttle body is formed of resin, but may be formed of metal such as aluminum as in the prior art.

  Further, in the first embodiment, the bypass air passage through which air flows in the path of the upstream space 20 (blocking recess) → the air inlet 22 → the space in the surrounding wall 24 → the air outlet 23 → the downstream space 21. 27, a bypass vent is formed in the partition wall 19 that partitions the upstream space 20 (blocking recess) and the downstream space 21, and the upstream space 20 (blocking recess) → bypass vent → downstream. A bypass air passage may be formed in the path of the side space 21, and a bypass air flow rate adjusting unit that adjusts the opening area of the bypass vent with a slide valve or the like may be provided.

  In the first embodiment, other actuators such as a rotary solenoid and a linear solenoid may be used as a drive source for the ISC valve 28 instead of the step motor 26.

1 is a longitudinal sectional view of a throttle body showing a first embodiment of the present invention. Front view of throttle body Cross-sectional view of the periphery of the intake pipe pressure sensor The longitudinal cross-sectional view of the throttle body which shows the 2nd Embodiment of this invention The longitudinal cross-sectional view of the throttle body which shows the 3rd Embodiment of this invention The longitudinal cross-sectional view of the throttle body which shows the 4th Embodiment of this invention Vertical section of a conventional throttle body

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Throttle body 12 ... Intake pipe 13 ... Surge tank 15 ... Outer pipe 16 ... Inner pipe 18 ... Throttle valve 19 ... Bulkhead 20 ... Blocking recessed part (upstream space)
DESCRIPTION OF SYMBOLS 21 ... Downstream space 22 ... Air inflow port 23 ... Air outflow port 24 ... Enclosure 26 ... Step motor 27 ... Bypass air passage 28 ... ISC valve (Bypass air flow rate adjusting means)
DESCRIPTION OF SYMBOLS 30 ... Intake pipe pressure sensor 32 ... Pressure detection part 34 ... Purge hole 41 ... Throttle body 42 ... Blocking recessed part 43 ... Throttle body 44 ... Blocking recessed part 45 ... Throttle body 46 ... Outer pipe 47 ... Inner pipe 48 ... Bulkhead 49: Blocking recess (upstream space)
50 ... downstream space

Claims (2)

In a throttle valve device of an internal combustion engine provided in a tubular throttle body so as to be able to open and close a throttle valve that controls the amount of intake air,
In the inner periphery of the throttle body, at least a lower portion where moisture is transmitted from the upstream side of the throttle valve to the inner peripheral surface of the intake pipe, and a U-shaped blocking recess for blocking moisture transmitted from the upstream side. The blocking recess is configured so as not to have any other communication path connected to the lower part where the blocked moisture is accumulated, and the opening of the blocking recess is positioned upstream of the throttle valve. A throttle valve device for an internal combustion engine, characterized in that the opening of the blocking recess faces from the downstream side to the upstream side of the throttle valve. The throttle valve device for an internal combustion engine according to claim 1, wherein the throttle body is integrally formed of resin.

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