JP3745434B2 - Engine intake air amount control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an intake air amount control device for maintaining a rotational speed at a required speed during idling of an automobile engine.
[0002]
[Prior art]
Mechanical load generated during warm-up operation due to the high viscosity of the lubricating oil when the engine is started in the cold state in winter, or in the winter heating unit operating state, summer cooling unit operating state or ventilator operating state In order to overcome the electrical load that these devices put on the engine when idling, the engine idling speed needs to be higher than normal.
[0003]
For this purpose, a bypass that short-circuits the upstream and downstream sides of the throttle valve is provided in the intake passage of the engine, and an adjustment valve that opens and closes according to the engine temperature and the operating condition of the equipment is installed in this bypass. The idling speed is increased by the air flowing through the bypass while being kept in the air (see JP-A-51-2834).
[0004]
In Japanese Patent Laid-Open No. 51-2834, as one of intake air amount control means at idling, a valve body of a regulating valve installed in a bypass is rotated by an electric servo mechanism composed of a stepping motor or a DC motor. Means for measuring the bypass air flow rate by controlling the degree of overlap between the air passage provided in the body and the bypass, that is, the rotational position of the valve body is shown.
[0005]
On the other hand, in an engine system including a blow-by gas processing device and an exhaust gas recirculation device, impurities such as oil and carbon are mixed into the air flowing through the intake passage. Further, in an engine system using a gaseous fuel such as LPG as a fuel, impurities such as tar contained in the fuel are mixed into the air flowing through the intake passage.
[0006]
When air containing impurities flows through the bypass and passes through the regulating valve, it is inevitable that impurities adhere to the surface of the valve body. And when the engine is stopped for a long time, the adhering impurities harden during that time and the impurities that have entered the circumferential clearance between the valve body and the valve chamber cause the valve body to adhere and prevent the operation during the next engine operation. It becomes.
[0007]
[Problems to be solved by the invention]
As a means to eliminate the phenomenon that the operation of the rotary regulator valve is hindered by the adhesion impurity hardening, it has been proposed to provide an adhesion prevention layer such as a fluororesin layer on the outer peripheral surface of the valve body that is difficult for impurities to adhere. It is difficult to manage the dimensional tolerance of the circumferential clearance between the body and the valve chamber, which is problematic for practical use. Therefore, it has been proposed to increase the circumferential clearance so that impurities attached to the valve body do not adhere to the valve chamber. This is accompanied by a disadvantage that the engine idling speed cannot be properly maintained by deviating the engine.
[0008]
The present invention is intended to solve the problem that there was no appropriate measure to prevent the sticking of the valve body due to adhesion of impurities that cannot be avoided in the rotary type regulating valve without impairing the function of the regulating valve, To prevent the adhering impurities from sticking to the valve body and prevent operation while the engine is stopped for a long time, and to reduce the air leakage during operation and to control the intake air amount appropriately. Objective.
[0009]
[Means for Solving the Problems]
That is, according to the present invention, at least one lightening groove is provided on the same circle as the air passage of the valve body so as to open to the outer peripheral surface, and a plurality of relief grooves are provided on the same circle on the valve chamber side peripheral surface. A directional gap was provided. When the bypass air flow rate is controlled, the valve body is fully closed with at least a part of the outer peripheral surface portion between the air passage and the hollow groove overlapping the inner peripheral surface portion between the relief grooves of the valve chamber. And a predetermined amount of air that is measured according to the degree of overlap between the air passage and the bypass while keeping the amount of air leakage through the gap between the valve body and the valve chamber to a very small amount. Can be supplied to the engine. Also, when the electric servo mechanism is not energized, the valve body is stopped at the position where the outer peripheral surface portion faces the escape groove without overlapping the inner peripheral surface portion. There is no longer a situation in which the operation is hindered due to being firmly separated from the indoor side even when cured.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to the drawings. In FIG. 1 and FIG. 2, an adjustment valve 5 is disposed on the side of a throttle valve 3 that opens and closes an intake passage 2 of a throttle body 1 installed in an intake system of an engine. A housing 6 is airtightly fixed by a mounting screw 8 with a sealing material 7 interposed therebetween.
[0011]
The housing 6 has a circular valve chamber 9 whose one end is closed and the other end is open, and a short cylindrical valve body 10 and bearings 13 fitted to valve shafts 11 and 12 projecting at both ends thereof. 14 is fitted into the valve chamber 9 from the open end, and the valve body 10 is rotatably supported on the housing 6 by bearings 13 and 14 and is housed in the valve chamber 9.
[0012]
The valve body 10 has an air passage 15 composed of a recess opened to the outer peripheral surface of the central portion over a range of about 120 to 130 degrees in the circumferential direction, and circumferentially on the opposite side across the central axis. A lightening groove 16 formed of a recess opened on the outer peripheral surface of the central portion is provided over a range of about 90 degrees.
[0013]
In addition, a bypass 18 is formed in the throttle body 2 and the housing 6 to short-circuit the upstream side and the downstream side of the intake passage 2 in a state where the throttle valve 3 is in the closed position, and the upstream side that is the entrance side thereof The passage portion 19 and the downstream passage portion 20 on the outlet side open to the valve chamber 9 toward the outer peripheral surface of the valve body 10 at a position perpendicular to each other. In the form shown in the figure, the downstream passage portion 20 is opened to the valve chamber 9 with the center line positioned on the line XX passing through the center axis of the valve body 10, and the upstream passage portion 19 is centered on the valve body 10. The valve chamber 9 is opened by being displaced toward the downstream passage portion 20 with respect to the line Y-Y perpendicular to the center axis. Further, the air passage 15 has an arcuate bottom surface 15a so that the air smoothly changes its direction when fully opened.
[0014]
The inner peripheral surface of the valve chamber 9 and the outer peripheral surface of the valve body 10 have a minimum clearance based on dimensional tolerances, and the width of the air passage 15 and the lightening groove 16 is set to the upstream passage portion 19 and The width of the downstream passage portion 20 is substantially the same.
[0015]
On the inner peripheral surface of the valve chamber 9, there are provided two relief grooves 22 and 23 consisting of shallow depressions extending from the line YY to both sides and extending in the circumferential direction of about 120 degrees. One end of the escape groove 22 communicates with the upstream passage portion 19. Further, the escape grooves 22 and 23 are formed substantially symmetrically across the line XX, and have a slightly larger width than the air passage 15 and the lightening groove 16.
[0016]
On the other hand, an electric servo mechanism 27 composed of a stepping motor, a DC motor or a solenoid is fixed to the open end of the valve chamber of the housing 6, and the valve shaft 12 is driven and the fully closed position shown in FIG. The valve body 10 is reciprocally rotated between the fully open position shown in FIG. 3C, and the bypass air flow rate is controlled by the degree of overlap between the air passage 15 and the downstream passage portion 20.
[0017]
In the fully closed position, the outer peripheral surface portions 25a and 25b between the air passage 15 of the valve body 10 and the lightening groove 16 are the smallest with the inner peripheral surface portions 24a and 24b where the relief grooves 22 and 23 of the valve chamber 9 are not provided. Overlapping with limited gaps, the air leakage from the upstream passage portion 19 to the downstream passage portion 20 through these gaps is very small. While the valve body 10 rotates counterclockwise in FIG. 3 from the fully closed position and reaches the fully open position through the half-open position shown in FIGS. 1, 2, and 3B, the two outer peripheral surface portions 25a of the valve body 10 are obtained. , 25b always overlap at least partly with the two inner peripheral surface portions 24a, 24b of the valve chamber 9, and the degree of overlap between the air passage 15 and the downstream passage portion 20 while keeping a small amount of air leaking around the outer peripheral surface. A predetermined amount of air is supplied to the engine.
[0018]
When the engine is stopped and the electric servo mechanism 27 is turned off, the valve body 10 rotates counterclockwise in FIG. 3 regardless of the position, and as shown in FIG. The surface portions 25 a and 25 b are stopped at positions facing the escape grooves 22 and 23. The rotation to the stop position is performed by the return means 28 formed of a torsion coil spring that is engaged at both ends with the valve shaft 12 and the housing 6, and is stopped at the position shown in FIG. It has become.
[0019]
When the air flows through the bypass 18, the air flows while contacting the surface exposed to the bypass 18 of the valve body 10, and impurities such as oil, carbon, and tar are contained on the side surface and the bottom surface 15 a of the air passage 15. And the outer peripheral surface portions 25a and 25b. When the engine is stopped for a long time, the adhering impurities are hardened during that time, and the adhering impurities on the outer peripheral surface portions 25a and 25b are also adhered to the inner peripheral surface of the valve chamber 9 to be hardened. This is a cause of hindering operation during the next engine operation.
[0020]
According to the illustrated embodiment, the outer peripheral surface portions 25a and 25b face the escape grooves 22 and 23 and have a large gap with the inner peripheral surface of the valve chamber 9 when the engine is stopped. The phenomenon of adhering to the inner peripheral surface of the can be avoided. Further, since the air passage 15 faces the inner peripheral surface portion 24a between the escape grooves 22 and 23, and the lightening groove 16 faces the inner peripheral surface portion 24a, impurities are attached to this portion. But there is no worry of sticking.
[0021]
FIG. 4 shows a different embodiment of the present invention. A short cylindrical valve element 40 has an air passage 45 penetrating perpendicularly to the central axis at the center, and the air passage 45 is provided in the central portion. The lightening grooves 46 and 47 are formed of two depressions opened on the outer peripheral surface of the center portion.
[0022]
Further, the housing 36 has an upstream passage portion 49 and a downstream passage portion 50 which are the inlet side of the bypass 48 opened to the valve chamber 39 toward the outer peripheral surface of the valve body 40 perpendicular to the central axis of the valve body 40. is doing.
[0023]
Further, on the inner peripheral surface of the valve chamber 39, there are provided two escape grooves 52.53 that are located between the upstream passage portion 49 and the downstream passage portion 50 and are formed of shallow recesses extending in the circumferential direction. One relief groove 52 has an end communicating with the upstream passage portion 49, and the other relief groove 53 has an end communicating with the downstream passage portion 50. These relief grooves 52 and 53 are provided substantially symmetrically with respect to the central axis of the valve body 40 and have a slightly larger width than the air passage 45 and the lightening grooves 46 and 47.
[0024]
When the valve body 40 is in the fully closed position during the operation of controlling the bypass air flow rate, the outlet end of the air passage 45 of the valve body 40 and one of the lightening grooves 46 as shown in FIG. The outer peripheral surface portion 55a between the air passage 45 faces the inner peripheral surface portion 54a between the downstream passage portion 50 of the valve chamber 39 and the one escape groove 52 with a minimum clearance, and the air passage 45 inlet end and the other end portion. The outer peripheral surface portion 55b between the lightening groove 47 and the inner peripheral surface portion 54b between the upstream passage portion 49 of the valve chamber 39 and the other escape groove 53 overlaps with a minimum gap, Leakage of air passing through these gaps from the upstream passage portion 49 to the downstream passage portion 50 is very small.
[0025]
While the valve body 40 is rotated counterclockwise in the figure from the fully closed position to reach the fully open position shown in FIG. 4C through the half-open position shown in FIG. 4B, the two outer peripheral surface portions 55a of the valve body 40, 55b always overlaps at least partly with the inner peripheral surface portions 54a and 54b of the valve chamber 39, and the air passage 45, the upstream passage portion 49, the downstream passage portion 50 and the air passage 45 while keeping a small amount of air leaking around the outer peripheral surface. A predetermined amount of air corresponding to the degree of overlap is supplied to the engine.
[0026]
When the engine is stopped and the power is turned off, the valve body 40 rotates clockwise in any position regardless of the position, passes through the fully closed position, and as shown in FIG. The outer peripheral surface portions 55c and 55d on the opposite side across 55a and 55b and the air passage 45 therebetween are stopped at positions facing the escape grooves 52 and 53. The rotation to the stop position is performed by the return means similar to that of the above-described embodiment. Even in this embodiment, the outer peripheral surface portions 55a... 55d of the valve body 40 all face the escape grooves 52, 53 and have a large gap between the inner peripheral surface of the valve chamber 49 and the valve chamber 49. Since the thinning grooves 46 and 47 face the inner peripheral surface portions 54a and 54b and have a large gap, there is no fear of sticking even if the adhering impurities are cured.
[0027]
【The invention's effect】
As described above, according to the opening position to the valve chamber of the bypass, the shape of the air passage of the valve body, and the rotation angle between the fully closed position and the fully open position during operation set by these, According to the present invention, a groove is provided so that a narrow gap is formed between the valve body and the valve chamber during operation, but the valve body is placed at a position having no narrow gap between the valve chamber and the valve chamber when not operating. In addition to reducing the air leakage during operation and controlling the intake air volume appropriately to maintain the engine idling speed properly, the adhered impurities harden and the valve body sticks while the engine is stopped for a long time. It is possible to operate smoothly without causing inconvenience.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention.
2 is a cross-sectional view taken along line aa in FIG.
FIG. 3 is a cross-sectional view illustrating the operation of the embodiment of FIG.
FIG. 4 is a cross-sectional view illustrating the operation of a different embodiment of the present invention.
[Explanation of symbols]
2 intake passages, 3 throttle valves, 6, 36 housings, 9, 39 valve chambers, 10, 40 valve bodies, 15, 45 air passages, 16, 46, 47 cutout grooves, 18, 48 bypass, 22, 23, 53 , 54 relief groove, 24a, 24b, 54a, 54b inner peripheral surface portion, 25a, 25b, 55a, 55b outer peripheral surface portion,

Claims (1)

A bypass provided with an adjustment valve that rotates the valve body in the valve chamber of the housing by an electric servo mechanism is provided in the intake passage by short-circuiting the upstream side and the downstream side of the throttle valve, and the air passage of the valve body and the In the engine intake air amount control device that controls the intake air amount when idling according to the degree of overlap with the bypass;
A plurality of relief grooves are provided on the same circle as the inner circumferential surface of the valve chamber, and at least one lightening groove is provided on the same circle as the air passage of the valve body. Are provided with circumferential intervals;
When operating to control the flow rate of bypass air, the valve body is in a fully open position in a state where at least a part of the outer peripheral surface portion between the air passage and the hollow groove overlaps with the inner peripheral surface portion between the relief grooves of the valve chamber. And between fully closed positions;
The valve body is stopped at a position facing the escape groove without overlapping the outer peripheral surface portion with the inner peripheral surface when the electric servo mechanism is not energized;
An intake air amount control device characterized by being configured.

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