JP4424666B2 - Intake duct device for internal combustion engine for vehicle - Google Patents

Description

  The present invention relates to an intake duct device for taking air in the atmosphere into an internal combustion engine mounted on a vehicle such as a truck.

  In general, an intake duct device in an internal combustion engine mounted on a vehicle such as a truck connects a proximal end of an intake duct erected in a chimney shape to an air cleaner in the internal combustion engine, while an air By providing the opening to the atmosphere, atmospheric air is taken in from the opening, but rainwater or the like is sucked together with the air from the opening to the atmosphere at the tip of the intake duct.

  Therefore, in Patent Document 1 as a prior art, the upper end of the intake duct is covered with a hat body having an opening to the atmosphere on the lower surface, and atmospheric air is discharged from the opening to the atmosphere on the lower surface of the hat body. On the other hand, a cap is provided on the outer surface of the lower end of the cap body so as to extend in the circumferential direction, and rainwater sprayed on the outer surface of the cap body is collected on the cap. It has been proposed to reduce the inhalation of rainwater into the intake duct by flowing down as large water droplets.

Further, Patent Document 1 as another prior art is such that the upper end portion of the intake duct standing in a chimney shape is curved in an inverted U shape so that the opening to the atmosphere at the front end faces downward. Thus, it has been proposed to reduce the intake of rainwater into the intake duct.
JP-A-8-91058 JP-A-8-48162

  However, in the former configuration, since the cap body is covered, the structure becomes complicated and the size of the cap body is increased, and the catch on the cap body is clogged due to adhesion and accumulation of dust in the atmosphere. In addition, since the rainwater collected in the receptacle overflows from the receptacle and drops into small droplets, there is a problem that the risk of inhaling rainwater together with atmospheric air increases.

  On the other hand, in the latter configuration, the structure can be simplified and reduced in size compared to the former, but the peripheral edge of the opening is substantially the same as viewed from the direction perpendicular to the longitudinal direction of the intake duct. By being horizontal, the rainwater sprayed on the outer surface drips as relatively small water droplets from the circumferential portions of the periphery of the opening, and the small water droplets are sucked together with the atmospheric air. There is a problem that there is a great risk of being caught.

  An object of the present invention is to provide an intake duct that solves these problems.

In order to achieve this technical problem, the present invention
“The tip of the intake duct standing upright from the air cleaner in the internal combustion engine mounted on the vehicle is curved in an inverted U shape so that the opening to the atmosphere provided at the tip faces downward, and the opening is dust-proof. In an intake duct device provided with a filter for use,
A curved portion of the intake duct that is curved in an inverted U shape is tapered so that the cross-sectional area of the passage increases toward the opening when viewed from a direction perpendicular to the longitudinal direction of the intake duct. On the other hand, when the peripheral edge of the opening is viewed from the direction perpendicular to the longitudinal direction of the intake duct, the inner peripheral side portion of the peripheral U-shaped curve is set at the lowest position. An outward bulge for forming a recess into which the dustproof filter fits in a portion adjacent to the opening portion of the tip portion that is inclined obliquely upward from the portion and curved in an inverted U shape. The part was provided so as to extend over the entire periphery of the opening . "
It is characterized by that.

  When the peripheral edge of the downward opening of the intake duct is viewed from a direction perpendicular to the longitudinal direction of the intake duct, the rainwater sprayed on the outer surface of the tip of the intake duct is When flowing down to the peripheral edge of the opening while traveling along the outer side surface, the peripheral edge is inclined, so that it flows in the direction of the lower part of the peripheral edge while transmitting the peripheral edge with surface tension. It gathers in the part and then drops from this lower part into large water drops.

  On the other hand, when the tip of the intake duct is curved in an inverted U shape so that the opening to the atmosphere provided at the tip is downward, the flow rate of atmospheric air in the tip of the intake duct is It tends to be slower on the inner peripheral side of the curve and faster on the outer peripheral side of the curve.

  Therefore, when the peripheral edge of the opening is viewed from the direction perpendicular to the longitudinal direction of the intake duct, the portion on the inner peripheral side of the curved shape in the inverted U shape is the lowest position of the peripheral edge. The rainwater that collects in the lower part of the inclined peripheral edge hangs down as a large water droplet at the part where the flow rate of atmospheric air to the opening is slow. In other words, since the suction speed of the atmospheric air in the portion where the rainwater drops as a large water droplet falls, the suction of the rainwater into the intake duct together with the atmospheric air can be reliably reduced.

  In other words, according to the present invention, it is possible to reliably reduce the intake of rainwater into the intake duct while making the tip of the intake duct curved in an inverted U shape, which is extremely simple and compact. Has an effect.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  In this figure, reference numeral 1 denotes a truck provided with a cabin 3 at the front part of a vehicle body frame 2 supported by wheels 5 and a cargo bed 4 at the rear part. The internal combustion engine 6 is mounted on the side portion.

  Reference numeral 7 denotes an intake duct erected in a chimney shape from the internal combustion engine 6 at a portion between the cabin 3 and the loading platform 4.

The air intake duct 7 is made of a heat-resistant hard synthetic resin, and its cross section has a flat rectangular shape in which the dimension in the traveling direction in the truck 1 is reduced and the dimension in the direction perpendicular to the traveling direction in the truck 1 is increased. The base end of the internal combustion engine 6 is connected to an air cleaner (not shown), and the tip (upper end) is provided with an opening 8 to the atmosphere.
A filter 11 such as a dustproof wire mesh is detachably provided in the opening 8.

A curved portion 9 that is curved in an inverted U shape is provided at the distal end portion of the intake duct 7 so that the opening 8 faces downward when viewed from the traveling direction of the truck 1.
The curved portion 9 curved in an inverted U shape is tapered so that the cross-sectional area of the passage gradually increases toward the opening 8 when viewed from the direction perpendicular to the longitudinal direction of the intake duct 7. ing.

  In this case, a bulging portion 10 having a radius R is provided on the inner peripheral side of the bending portion 9 so as to reduce the air flow resistance in the bending portion 9.

  When the peripheral edge 8a of the opening 8 is viewed from a direction perpendicular to the longitudinal direction of the intake duct 7, an inner peripheral portion 8a 'of the inverted U-shaped curved portion 9 of the peripheral edge 8a is defined. The lowest position is set to be inclined obliquely upward from this portion by an appropriate angle θ.

Note that the peripheral edge 8a of the opening 8 bulges outward in a trumpet shape, thereby improving the rigidity of the peripheral edge 8a and promoting the flow of rainwater along the peripheral edge 8a, which will be described later. It is composed.
Further, in the portion adjacent to the opening 8 in the curved portion 9, an outwardly bulging portion for forming a recess 12 in which the periphery of the dustproof filter 11 is fitted is provided on the opening 8. It is provided so as to extend over the entire circumference.

  In this configuration, the atmospheric air sucked into the internal combustion engine 6 flows into the intake duct 7 from the downward opening 8.

  In this case, out of the flow of atmospheric air in the curved portion 8 in the intake duct 7, the flow rate indicated by the dotted arrow A1 on the inner peripheral side of the curve is slow, and the flow indicated by the dotted arrow A2 on the outer peripheral side of the curve. Tends to be faster.

  On the other hand, when the rainwater sprayed to the outer surface of the curved portion 8 in the intake duct 7 flows down to the peripheral edge 8a of the opening 8 while traveling along the outer surface as indicated by an arrow B, the peripheral edge Based on the fact that 8a is inclined at an appropriate angle θ, the peripheral edge 8a flows in the direction of the lowest part 8a ′ of the peripheral edge 8a while being transmitted by the surface tension, and gathers at the lower part 8a ′. From the lower portion 8a ', a large water droplet is dropped.

  That is, the rainwater that collects at the lower portion 8a ′ of the inclined peripheral edge 8a hangs down as a large water droplet at the portion where the flow rate of the atmospheric air to the opening 8 is slow. Since the suction speed of the atmospheric air in the lower portion 8a ′ that drops as a large water droplet is slow, it is possible to reliably reduce the suction of rainwater into the intake duct 7 together with the atmospheric air.

  According to the experiments by the present inventors, the minimum value of the inclination angle θ at the peripheral edge 8a of the opening 8 is 15 degrees, and when it is less than this, the flow of rainwater transmitted through the inclined peripheral edge 8a. Will drop. In addition, the larger the inclination angle θ, the better the flow of rainwater transmitted by the inclined peripheral edge 8a. However, the maximum value is 45 degrees, and if it exceeds this, it is blown into the opening 8. There was a lot of rainwater.

It is a side view of a truck. FIG. 2 is an enlarged side view taken along the line II-II in FIG. 1. FIG. 3 is an enlarged sectional view taken along line III-III in FIG. 2. FIG. 4 is an enlarged sectional view taken along line IV-IV in FIG. 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Truck 6 Internal combustion engine 7 Duct for intake 8 Opening part 8a Periphery of opening part 8a 'Low part in peripheral part 9 Curved part 10 Swelling part 11 Filter

Claims (1)

The tip of an intake duct standing from an air cleaner in an internal combustion engine mounted on a vehicle is curved in an inverted U shape so that the opening to the atmosphere provided at the tip faces downward, and the opening is dust-proof In an intake duct device provided with a filter ,
A curved portion of the intake duct that is curved in an inverted U shape is tapered so that the cross-sectional area of the passage increases toward the opening when viewed from a direction perpendicular to the longitudinal direction of the intake duct. On the other hand, when the peripheral edge of the opening is viewed from the direction perpendicular to the longitudinal direction of the intake duct, the inner peripheral side portion of the peripheral U-shaped curve is set at the lowest position. An outward bulge for forming a recess into which the dustproof filter fits in a portion adjacent to the opening portion of the tip portion that is inclined obliquely upward from the portion and curved in an inverted U shape. An intake duct device for an internal combustion engine for a vehicle , wherein the portion is provided so as to extend over the entire periphery of the opening .

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