Throttle Device

Abstract

To provide a throttle device capable of suppressing malfunction due to freezing.SOLUTION: A throttle device comprises a throttle body provided in an intake passage of an internal combustion engine, and a throttle valve provided in the throttle body and having a valve body that can be opened and closed. A portion of the throttle body below an end part of the valve body has a groove. An end part of the groove in a circumferential direction of the intake passage is provided with a downwardly convex curved surface.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a throttle device. [Background technology]

[0002] A throttle device is provided in the intake passage. The amount of air introduced into the internal combustion engine can be adjusted by opening and closing a throttle valve of the throttle device (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 3-17156 Summary of the Invention [Problem to be solved by the invention]

[0004] Moisture that adheres to the throttle device falls and accumulates between the throttle valve and the throttle body. When the internal combustion engine is stopped, the moisture freezes. The freezing inhibits the operation of the throttle valve. Therefore, the objective of the present invention is to provide a throttle device that can suppress malfunctions caused by freezing. [Means for solving the problem]

[0005] The above object is to provide a throttle valve having a throttle body provided in an intake passage of an internal combustion engine, the throttle valve being provided in the throttle body and having a valve body that can be opened and closed, the throttle valve being provided at an end of the valve body in the direction of gravity of the throttle body. Under This can be achieved by a throttle device in which the portion (a) has a groove, and a downwardly convex curved surface is provided at an end of the groove in the circumferential direction of the intake passage.

[0006] The curved surface may be curved from the outside to the inside of the groove.

[0007] The throttle valve has a shaft, and the valve body rotates about the shaft to open and close. and the gravity direction In the valve body, a lower portion of the end portion may have the groove.

[0008] When the internal combustion engine stops, the valve body stops, and when the valve body stops, In the gravity direction, The groove may be located beneath an end of the valve disc.

[0009] The groove may be provided downstream of the valve body in the intake passage. Effect of the Invention

[0010] It is possible to provide a throttle device that is capable of suppressing malfunctions caused by freezing. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram illustrating an engine system. [Diagram 2] Fig. 2(a) is a cross-sectional view illustrating the throttle device, Fig. 2(b) is a front view illustrating the throttle device, and Fig. 2(c) is a perspective view illustrating the groove. [Diagram 3] 3(a) to 3(c) are cross-sectional views illustrating a throttle device according to a comparative example. [Figure 4] Figures 4(a) and 4(c) are cross-sectional views illustrating the throttle device according to the embodiment, and Figure 4(b) is a perspective view illustrating the throttle device. [Diagram 5] FIG. 5 is a diagram illustrating the flow rate characteristics of the throttle valve. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The PCV structure of this embodiment will be described below with reference to the drawings. Fig. 1 is a schematic diagram illustrating an engine system 100. The engine system 100 has an internal combustion engine 10, an ECU (Electronic Control Unit) 25, a PCV structure 30, and a throttle device 40.

[0013] The internal combustion engine 10 is, for example, a gasoline engine. The internal combustion engine 10 includes a cylinder block 20, a cylinder head 21, a crankcase 27, a fuel injector 13, a piston 24, a crankshaft 22, an intake valve 17, and an exhaust valve 19.

[0014] A cylinder head 21 is attached on top of the cylinder block 20, and a crankcase 27 is attached below the cylinder block 20. A crankshaft 22 is housed inside the crankcase 27. One end of a connecting rod 23 is connected to a piston 24, and the other end is connected to the crankshaft 22. A combustion chamber 26 is defined by the cylinder block 20, the cylinder head 21, and the piston 24.

[0015] An intake valve 17, an exhaust valve 19, and a fuel injection valve 13 are provided in a cylinder head 21. The fuel injection valve 13 performs in-cylinder injection. The fuel injection valve 13 is provided in an intake passage 12, and may perform port injection.

[0016] The intake passage 12 and the exhaust passage 14 are connected to the cylinder head 21. In the intake passage 12, an air cleaner 15, an air flow meter 16, and a throttle device 40 are provided in this order from the upstream side. The air cleaner 15 removes dust and other particles from the air in the intake passage 12 to purify the air. The air flow meter 16 detects the flow rate of air in the intake passage 12.

[0017] The throttle device 40 has a throttle body 42 and a throttle valve 44. The throttle body 42 is provided midway through the intake passage 12, and is part of the piping for introducing air. The throttle valve 44 is provided inside the throttle body 42, and can be opened and closed. The larger the opening of the throttle valve 44, the greater the air flow rate. The smaller the opening of the throttle valve 44, the smaller the air flow rate.

[0018] The air in the intake passage 12 is introduced into the combustion chamber 26 in response to the opening of the intake valve 17. The fuel injector 13 injects fuel into the combustion chamber 26. A mixture of fuel and air is generated in the combustion chamber 26. The mixture is burned, for example, by ignition by a spark plug (not shown). The combustion of the mixture moves the piston 24 downward. Power is transmitted from the piston 24 to the crankshaft 22, causing the crankshaft 22 to rotate. The piston 24 reciprocates up and down. When the exhaust valve 19 opens, the exhaust gas after combustion is discharged into the exhaust passage 14. The exhaust gas is purified by a catalyst (not shown) provided in the exhaust passage 14.

[0019] Unburned gas (blow-by gas) may leak from the combustion chamber 26 into the crankcase 27. The PCV structure 30 is a device for returning the blow-by gas from the crankcase 27 to the intake passage 12. The PCV structure 30 has a PCV passage 32 and a PCV piping 34. The PCV passage 32 is provided inside the cylinder block 20 and the cylinder head 21, and extends to the crankcase 27.

[0020] The PCV piping 34 is provided outside the internal combustion engine 10 and extends from the internal combustion engine 10 to the intake passage 12. One end of the PCV piping 34 is connected to the cylinder head 21 of the internal combustion engine 10 and communicates with the PCV passage 32. The other end of the PCV piping 34 is connected to the intake passage 12 downstream of the throttle valve 44. Blow-by gas flows through the PCV passage 32 and the PCV piping 34, and is supplied from the crankcase 27 to the intake passage 12. The blow-by gas is introduced into the combustion chamber 26 together with air and combusted.

[0021] The ECU 25 is a control device that includes a calculation device such as a CPU (Central Processing Unit) and storage devices such as a flash memory, a ROM (Read Only Memory) and a RAM (Random Access Memory). The ECU 25 acquires the air flow rate detected by the air flow meter 16. The ECU 25 controls the amount and timing of fuel injection from the fuel injection valve 13. The ECU 25 controls the opening of the throttle valve 44.

[0022] Fig. 2(a) is a cross-sectional view illustrating the throttle device 40. The U direction in Fig. 2(a) is the upstream direction of the intake passage 12. The D direction is the downstream direction of the intake passage 12. The air cleaner 15 in Fig. 1 and the like are provided on the upstream side (U side) of the throttle body 42. The PCV piping 34 and the internal combustion engine 10 are located on the downstream side (D side) of the throttle body 42. Fig. 2(b) is a front view illustrating the throttle device 40, showing the throttle device 40 as viewed from the D direction. Arrow C in Fig. 2(b) indicates the circumferential direction of the intake passage 12.

[0023] As shown in Figures 2(a) and 2(b), the throttle device 40 has a throttle body 42 and a throttle valve 44. The throttle valve 44 is, for example, a butterfly valve, and has a shaft 46 and a valve element 48. The shaft 46 traverses the throttle body 42. The valve element 48 is a plate-shaped member and is rotatable about the shaft 46 as a rotation axis. When the valve element 48 rotates in the direction of arrow R1 in Figure 2(a), the opening of the throttle valve 44 increases. When the valve element 48 rotates in the direction of arrow R2, the opening decreases. Figure 2(b) shows the throttle valve 44 in a closed state.

[0024] 2(a) shows the throttle device 40 when the internal combustion engine 10 is stopped. When the internal combustion engine 10 is stopped, the valve body 48 of the throttle valve 44 is inclined with respect to a direction perpendicular to the inner wall 42a of the throttle body 42 (opener opening). The lower end of the valve body 48 faces downstream, and the upper end faces upstream.

[0025] The throttle body 42 has a groove 50. Specifically, the groove 50 is provided in the inner wall of the throttle body 42 at a position facing the end (lower end) of the valve body 48 of the throttle valve 44. The groove 50 is a portion recessed downward from the inner wall 42a of the throttle body 42. As shown in FIG. 2(b), the groove 50 is U-shaped when viewed from the front.

[0026] Fig. 2(c) is a perspective view illustrating the groove 50. As shown in Figs. 2(b) and 2(c), curved surfaces 52 are provided at both ends of the groove 50 in the circumferential direction. The curved surfaces 52 are downwardly convex and curved from the outside toward the inside of the groove 50. The curved surfaces 52 are provided between the inner wall 42a and a bottom surface 54 of the throttle body 42. The bottom surface 54 of the groove 50 is located between the two curved surfaces 52. The bottom surface 54 may be a flat surface or a curved surface.

[0027] The width W, depth D1, and depth D2 of the groove 50 are, for example, several mm. The width W is, for example, greater than the depth D1 and depth D2. The radius of curvature of the curved surface 52 is, for example, several mm.

[0028] 3(a) to 3(c) are cross-sectional views illustrating a throttle device 40R according to a comparative example. The throttle body 42 of the throttle device 40R does not have the groove 50.

[0029] As shown in Fig. 3(a), a number of pieces of ice 60 adhere to the throttle valve 44. While the vehicle is running, moisture contained in blow-by gas and the like adheres to the throttle body 42 and the throttle valve 44. Air flows into the throttle body 42 from the upstream side. If the air temperature is, for example, around 0°C, the moisture freezes, and ice 60 forms.

[0030] As shown in FIG. 3(b), when the internal combustion engine 10 stops, hot air is discharged from the internal combustion engine 10 into the intake passage 12. The hot air melts the ice 60, which turns into water droplets and falls. A puddle forms between the valve element 48 of the throttle valve 44 and the throttle body 42. After the internal combustion engine 10 is stopped for several hours, for example, the puddle freezes and ice 62 forms. The ice 62 is larger than the ice 60 shown in FIG. 3(a) and is in contact with the lower end of the valve element 48. The ice 62 inhibits the operation of the valve element 48.

[0031] As shown by arrow R1 in Figure 3(c), when the throttle valve 44 opens, the valve disc 48 pushes out ice 62. Therefore, the throttle valve 44 is easy to open. On the other hand, as shown by arrow R2, when the throttle valve 44 closes, the valve disc 48 is difficult to rotate because there is ice 62 between the valve disc 48 and the inner wall 42a of the throttle body 42. In this way, the ice 62 inhibits the operation of the throttle valve 44, making it particularly difficult to close.

[0032] 4(a) and 4(c) are cross-sectional views illustrating the throttle device 40 according to the embodiment. FIG.

[0033] 4(a), the moisture freezes to produce ice 60. When the internal combustion engine 10 stops, hot air is emitted from the internal combustion engine 10 into the intake passage 12. The hot air melts the ice 60, turning it into water droplets that fall.

[0034] As shown by the arrows in FIG. 4(b), water droplets 64 flow along the inner wall 42a of the throttle body 42 and fall into the groove 50. The curved surface 52 of the groove 50 is recessed below the inner wall 42a and has a downwardly convex shape. The water droplets 64 are accelerated by the curved surface 52 and flow into the bottom surface 54 of the groove 50. The water droplets 64 accelerated by the curved surface 52 overcome the surface tension of the water and fall from the groove 50 to the outside of the groove 50 without forming a puddle. According to the embodiment, the amount of water that accumulates below the valve body 48 can be reduced compared to the comparative example.

[0035] As shown in Fig. 4(c), water that has accumulated under the valve body 48 freezes to form ice 66. Because the amount of water is reduced, the ice 66 is smaller than the ice 62 in the comparative example. For this reason, the operation of the throttle valve 44 is less likely to be hindered by the ice 66.

[0036] According to this embodiment, the throttle body 42 has a groove 50 in a portion below the end of the valve body 48 of the throttle valve 44. A downwardly convex curved surface 52 is provided at the end of the groove 50 in the circumferential direction (arrow C in FIG. 2(b)). Water droplets 64 are accelerated by the curved surface 52, causing the water to flow down from the groove 50. Water is less likely to accumulate in the groove 50. Therefore, ice 66 that forms below the valve body 48 is smaller than the ice 62 in the comparative example. Malfunctions due to freezing are suppressed, and the throttle valve 44 can be opened and closed.

[0037] The curved surface 52 curves from the outside to the inside of the groove 50. The inner wall 42a of the throttle body 42 and the bottom surface 54 of the groove 50 are connected by the curved surface 52. Water droplets 64 flowing along the inner wall 42a are accelerated by the curved surface 52 and fall to the bottom surface 54, and then fall from the bottom surface 54 to the outside of the groove 50. Water is less likely to accumulate under the valve disc 48, and ice 66 that forms under the valve disc 48 becomes smaller. Malfunctions due to freezing are suppressed, and the throttle valve 44 can be opened and closed.

[0038] The throttle valve 44 is a butterfly valve and has a shaft 46 and a valve body 48. In the direction intersecting the shaft 46 (the up-down direction in FIG. 2(a)), the throttle body 42 has a groove 50 in the portion below the valve body 48. The groove 50 is located on the trajectory of the rotation of the valve body 48. Water is less likely to accumulate below the valve body 48, and the ice 66 that forms below the valve body 48 is smaller. Because the ice 66 is small, it is less likely to collide with the valve body 48. Even if the valve body 48 collides with the ice 66, because the ice 66 is small, the ice 66 can be peeled off by the valve body 48. The rotation of the valve body 48 is not easily hindered by ice. The throttle valve 44 can be opened and closed.

[0039] When the internal combustion engine 10 stops, the operation of the throttle valve 44 also stops. As shown in FIG. 2(a) and other figures, the valve body 48 of the throttle valve 44 stops at a position inclined with respect to a direction perpendicular to the inner wall 42a. The groove 50 is located below the lower end of the stopped valve body 48. Water droplets adhering to the valve body 48 fall into the groove 50 and flow down from the groove 50. Water is less likely to accumulate under the valve body 48, and large pieces of ice are less likely to form. Malfunctioning of the valve body 48 is suppressed. The groove 50 is located below the valve body 48 in the direction of gravity, and is preferably located at the lowest part of the throttle body 42 in particular. Water droplets flow into the groove 50, are accelerated by the curved surface 52, and fall. Water droplets formed in the throttle device 40 can be removed and freezing can be suppressed.

[0040] The groove 50 is located downstream of the valve body 48. For example, when blow-by gas or the like comes into contact with the valve body 48, water droplets adhere to the downstream surface of the valve body 48. Because the groove 50 is located downstream of the valve body 48, the water droplets are accelerated by the curved surface 52 of the groove 50 and fall. Water is less likely to accumulate under the valve body 48, and large pieces of ice are less likely to form. Malfunctioning of the valve body 48 is suppressed.

[0041] At least one of the two ends of the groove 50 may be provided with a curved surface 52. For example, one of the two ends may be provided with the curved surface 52, and the other may be a wall perpendicular to the bottom surface 54. In order to accelerate the water droplets at both ends of the groove 50, it is preferable that the groove 50 has a curved surface 52 at both ends.

[0042] 2(a)。 When the internal combustion engine 10 is idling, the opening of the throttle valve 44 becomes smaller than that in Fig. 2 (a). The valve body 48 rotates in the direction of the arrow R2 and moves away from the groove 50. The effect of the groove 50 on the air flow becomes smaller.

[0043] FIG. 5 is a diagram illustrating the flow rate characteristics of the throttle valve 44. The horizontal axis represents the opening of the throttle valve 44. The vertical axis represents the air flow rate. The dashed line represents a comparative example. The dotted and solid lines represent embodiments. In the dotted line example, the groove 50 is smaller than in the solid line example. In the solid line example, the groove 50 is larger than in the dotted line example, for example, the width of the groove 50 is twice as large as in the dotted line example.

[0044] The greater the throttle opening, the greater the difference in flow rate between the comparative example and the embodiment. The flow rate in the embodiment is greater than that in the comparative example. In particular, in the example where the groove 50 is large, the flow rate is greater. The flow rate in the example where the groove 50 is small (dotted line example) is closer to that of the comparative example than the example where the solid line is shown. At a throttle opening of 12°, the flow rate in the example where the solid line is shown is about 9% greater than that of the comparative example where the dashed line is shown. This difference in flow rate is comparable to the change in flow rate caused by manufacturing errors. According to the embodiment, the effect on the air flow rate can be suppressed within the error range, and malfunctions due to freezing can be suppressed. In particular, in the example where the groove 50 is small (dotted line example), the change in flow rate is smaller.

[0045] Although a preferred embodiment of the present invention has been described in detail above, the present invention is not limited to such a specific embodiment, and various modifications and variations are possible within the scope of the gist of the present invention described in the claims. [Explanation of symbols]

[0046] 10 Internal combustion engine 12 Intake passage 14 Exhaust passage 15 Air cleaner 16 Air flow meter 17 Intake valve 19 Exhaust valve 25 ECU 20 Cylinder block 21 Cylinder head 22 Crankshaft 23 Connecting rod 24 Piston 26 Combustion chamber 30 PCV structure 32 PCV passage 34 PCV piping 40, 40R throttle device 42 Throttle body 42a Internal wall 44 Throttle valve 46 Axis 48 Valve body 50 grooves 52 Curved surface 54 Bottom 60, 62, 66 Ice 64 water drops 100 Engine System

Claims

1. A throttle body provided in an intake passage of the internal combustion engine; a throttle valve provided in the throttle body and having a valve body that can be opened and closed, A portion of the throttle body below an end of the valve body in a gravity direction has a groove, A throttle device in which a downwardly convex curved surface is provided at an end of the groove in the circumferential direction of the intake passage.

2. 2. The throttle device according to claim 1, wherein the curved surface is curved from the outside to the inside of the groove.

3. The throttle valve has a shaft. The valve body opens and closes by rotating about the shaft, 3. The throttle device according to claim 1, wherein a portion of the throttle body below an end of the valve disc in the direction intersecting the axis and in the direction of gravity has the groove.

4. When the internal combustion engine stops, the valve body stops, The throttle device according to any one of claims 1 to 3, wherein the groove is located below an end of the valve body in the direction of gravity when the valve body is stopped.

5. 5. The throttle device according to claim 1, wherein the groove is provided downstream of the valve body in the intake passage.

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