JP4506798B2 - Secondary air supply device for internal combustion engine - Google Patents

Description

  The present invention relates to a secondary air supply device for an internal combustion engine, and more particularly to a secondary air supply device for an internal combustion engine in which secondary air is supplied from an air cleaner upstream of a catalyst provided in an exhaust pipe.

  In an internal combustion engine mounted on a vehicle such as an automobile, a catalyst such as platinum or palladium formed on the surface of a ceramic honeycomb substrate or the like is used in order to appropriately purify exhaust gas with an exhaust purification catalyst. It must be raised to a predetermined activation temperature. For this reason, the exhaust gas is hardly purified from when the internal combustion engine is started until the catalyst reaches a predetermined activation temperature.

  In order to eliminate such problems, in order to purify hydrocarbons (HC) and carbon monoxide (CO) in the exhaust gas when starting from a state where the catalyst is cold, air is supplied to the exhaust pipe. There exists what was provided with the secondary air supply apparatus to supply, and as such a secondary air supply apparatus, it shows like FIG. 10 (for example, refer patent document 1).

In FIG. 10, an exhaust manifold 2 is connected to an engine 1 as an internal combustion engine, and an exhaust pipe 3 is connected to the exhaust manifold 2 via a catalyst device 4. In addition, a secondary air supply pipe 6 is connected to the exhaust manifold 2 via an electromagnetic ASV (Air Switching Valve) 5. The electromagnetic ASV 5 communicates and shuts off the secondary air supply pipe 6 and the exhaust manifold 2. Thus, the secondary air supply pipe 6 is controlled to open and close.
The secondary air supply pipe 6 is connected to a secondary air lead-out portion 7a of an air pump 7. The air pump 7 sucks air from the secondary air introduction portion 7b as indicated by an arrow to supply secondary air. The pipe 6 is supplied.

In the secondary air supply apparatus having such a configuration, the air introduced into the air pump 7 from the secondary air introduction portion 7b is driven by the driving force of the air pump 7 via the secondary air supply pipe 6 and the electromagnetic ASV 5. When supplied to the exhaust manifold 2, the oxidation reaction of unburned components such as hydrocarbons (HC) and carbon monoxide (CO) contained in the exhaust gas is promoted, and as a result, unreacted components in the exhaust gas The catalyst of the catalyst device 4 can be activated at an early stage by the heat of combustion based on the oxidation reaction between the fuel component and air.
JP 2005-163708 A

  However, in such a conventional secondary air supply device, when running in rainy weather or running in a pool, water containing water is introduced from the secondary air introduction part 7b to the air pump 7, and the secondary air is supplied from the air pump 7. When supplied to the exhaust manifold 2 through the air supply pipe 6 and the electromagnetic ASV 5, water may be sucked into the catalyst as it is.

  In particular, in an overcab in which the engine 1 is installed below the driver's seat, the engine 1 is installed at a position close to the road surface. Therefore, the air pump 7 can easily introduce air containing water. To the catalyst device 4 through the secondary air supply pipe 6, the electromagnetic ASV 5 and the exhaust manifold 2.

  When this water comes into contact with a high-temperature catalyst supported on the honeycomb base material of the catalyst device 4, the catalyst may be damaged. If the catalyst is damaged in this way, the catalyst performance deteriorates. There was a risk of it.

  The present invention has been made to solve the above-described conventional problems, and can prevent water from entering and damaging the catalyst and prevent deterioration of the catalyst performance. An object of the present invention is to provide a secondary air supply device for an internal combustion engine capable of performing

In order to achieve the above object, the secondary air supply device for an internal combustion engine according to the present invention includes: (1) a secondary air supply pipe whose one end is connected to the upstream side of the catalyst provided in the exhaust pipe; A supply pump that is connected to the other end of the secondary air supply pipe and supplies secondary air to the upstream side of the catalyst via the secondary air supply pipe, an air introduction section for introducing air, and air A cylindrical main body provided with an air outlet, and an air cleaner having a filtering element provided in the main body so as to be positioned between the air inlet and the air outlet, from the air inlet A secondary air supply device for an internal combustion engine , wherein the air introduced into the main body is swirled along an inner peripheral surface of the main body, the secondary air having one end connected to the supply pump. The outlet pipe and the secondary air outlet pipe A secondary air discharge pipe that is provided in the main body so as to be connected to the end and discharges secondary air from the main body to the supply pump, and the secondary air discharge pipe is an inner peripheral surface of the main body inwardly projecting of said body from said has a protrusion which air impinges for turning the inner circumferential surface of the body, the protrusion, a communication hole that communicates the main body and the secondary air outlet tube And the air introduction part is provided in the main body so as to be offset from the vertical central axis of the main body so as to guide the air introduced into the main body in one direction along the inner peripheral surface of the main body. Consists of things.

With this configuration , a protrusion that protrudes inward of the main body from the inner peripheral surface of the main body and collides with air swirling on the inner peripheral surface of the main body is provided, so that air swirling on the inner peripheral surface of the main body collides with the protrusion. It is possible to create an air flow that separates into upper and lower parts. For this reason, if water reaches the secondary air discharge pipe together with the air sucked into the main body from the air introduction part, the amount of water entrained inside the protrusion is reduced by the wall surface of the protrusion. Can be made. For this reason, only air can be led out from the secondary air discharge pipe to the supply pump through the secondary air lead-out pipe.

For this reason, only secondary air can be supplied from the supply pump to the exhaust pipe through the secondary air supply pipe, and water can be prevented from entering the catalyst in a high temperature state. As a result, the catalyst can be prevented from being damaged, and the catalyst performance can be prevented from deteriorating.
In addition, since the secondary air discharge pipe has a protrusion that protrudes inward from the inner peripheral surface of the main body, even if water has reached the secondary air discharge pipe, the wall surface of the protrusion Thus, the amount of water entrained inside the protrusion can be reduced. For this reason, it can prevent more reliably that water will be discharged | emitted from a secondary air discharge pipe.

  In the secondary air supply device for an internal combustion engine according to (1) above, (2) the air cleaner has a cylindrical filtration element as the filtration element, and air introduced into the main body from the air introduction portion The air is swirled along the inner peripheral surface of the main body and guided to be filtered by the filter element, and the filtered air is joined to a hollow portion formed inside the filter element from the air outlet portion. It is comprised so that it may derive | lead out, and the said secondary air exhaust pipe is comprised from what adjoins to the said air introduction part, and is provided in the turning direction downstream of the air with respect to the said air introduction part.

  With this configuration, the air cleaner has a cylindrical filtering element, and the secondary air discharge pipe is provided close to the air introduction unit and downstream of the air introduction unit in the air swirling direction. The air introduced into the main body from the introduction portion can be largely swung along the inner peripheral surface of the main body and led out from the secondary air discharge pipe.

  Therefore, the air introduced from the air introduction part into the main body can be moved by a long distance between the air introduction part and the secondary air discharge pipe. For this reason, water can be efficiently separated from the air introduced into the main body while reducing the size of the air cleaner, and only air can be supplied from the secondary air discharge pipe to the supply pump through the secondary air outlet pipe. .

  In the secondary air supply device for an internal combustion engine according to the above (1) or (2), (3) the secondary air discharge pipe is configured to be provided above the main body.

  With this configuration, when water separated from the air falls on the bottom surface of the main body until the air moves from the air introduction part to the secondary air discharge pipe, the water is led out from the secondary air discharge pipe. Can be surely prevented.

  That is, there is a possibility that water that has fallen to the bottom surface of the main body due to negative pressure by the piston during the suction process of the piston may be sucked up, but was sucked up from the bottom surface of the main body by providing a secondary air discharge pipe above the main body. It is possible to make it difficult for water to reach the secondary air discharge pipe, and it is possible to reliably prevent water from being led out from the secondary air discharge pipe.

(2) In the secondary air supply device for an internal combustion engine according to (1) to (3) , ( 4 ) the diameter of the communication hole of the projecting portion is increased from the inner peripheral surface of the main body toward the inner side of the main body. It is composed of what will be done.

  With this configuration, the diameter of the communication hole of the projecting portion is increased from the inner peripheral surface of the main body toward the inside of the main body, so that the flow path of the communication hole on the upstream side in the secondary air outlet direction is connected to the downstream side in the outlet direction. It can be made wider than the channel of the hole.

  For this reason, the flow velocity of the air introduced into the communicating hole of the protruding portion on the upstream side in the secondary air outlet direction can be slowed down, and it is difficult to introduce water together with the air into the secondary air discharge pipe. It is possible to more reliably prevent water from being discharged from the pipe.

  According to the present invention, it is possible to provide a secondary air supply device for an internal combustion engine that can prevent water from entering and damaging the catalyst and prevent deterioration of catalyst performance. it can.

  Embodiments of a secondary air supply device for an internal combustion engine according to the present invention will be described below with reference to the drawings.

(First embodiment)
1 to 5 are views showing a first embodiment of a secondary air supply device for an internal combustion engine according to the present invention.

First, the configuration will be described.
In FIG. 1, an engine 11 as a four-cylinder internal combustion engine has a combustion chamber of each cylinder communicating with an exhaust manifold 12 via an exhaust port. The exhaust manifold 12 is connected to an exhaust pipe 13 via a catalyst device 14. It is connected.

  The catalyst device 14 is composed of a honeycomb base material or a granular activated alumina support with a catalyst such as platinum or palladium attached in a main body case. Oxidation is performed.

  One end of a secondary air supply pipe 16 is connected to the exhaust manifold 12 via an electromagnetic ASV (Air Switching Valve) 15. The electromagnetic ASV 15 communicates the secondary air supply pipe 16 and the exhaust manifold 2. The secondary air supply pipe 16 is controlled to open and close so as to be shut off.

The other end of the secondary air supply pipe 16 is connected to a secondary air outlet 17a of an air pump 17 as a supply pump. A secondary air outlet 18b is connected to the secondary air inlet 17b of the air pump 17. A cyclone type air cleaner 20 is connected through this. That is, the secondary air outlet pipe 18 has one end connected to the air pump 17 and the other end connected to the air cleaner 20.
The electromagnetic ASV 15 is provided upstream of the catalyst device 14 provided in the exhaust pipe 13, and secondary air is introduced from the air pump 17 to the upstream side of the catalyst device 14. The secondary air refers to air that is supplied to the upstream side of the catalyst device 14 and mixed with the gas exhausted from the combustion chamber. The electromagnetic ASV 15 and the air pump 17 are controlled by an ECU (Engine Control Unit) (not shown).

  The air cleaner 20 has a function of filtering outside air in order to send air that does not contain dust (dust, oil, etc.) to the combustion chamber of the engine 11, and the air cleaner 20 is as shown in FIGS. In addition, a casing 24 as a main body having an air introduction portion 21 and an air outlet portion 22, a cylindrical filtration element 27 accommodated in the casing 24, and a fastener 25 as a support member for suspending the filtration element 27 on the casing 24. It is comprised including.

  As shown in FIG. 2, the casing 24 is formed in a substantially cylindrical shape, and is provided with an air introduction portion 21 that is inclined at an angle of about 45 ° with respect to the vertical direction. In addition, an air outlet 22 is provided on the upper wall of the casing 24, and the air inlet 21 and the air outlet 22 are open in the casing 24.

  The air outlet 22 is provided with a resonator 23. The resonator 23 includes a housing having a space inside and a communication hole that communicates the housing with the air outlet 22 so that the air is led out. The air derived from the part 22 is silenced. The air outlet 22 is connected to an intake pipe (not shown), and the intake pipe communicates with a combustion chamber of each cylinder of the engine 11 via an intake manifold and an exhaust port (not shown).

  A dust pan 26 is provided at the bottom of the casing 24, and dust separated from the air is accumulated in the dust pan 26. In addition, the casing 24 of this Embodiment is shape | molded from resin materials, such as metal materials, such as a steel plate, or a polypropylene.

  The filter element 27 is formed in a hollow cylindrical shape, and although not described in detail, the filter element 27 is a well-known element in which an annular end plate is joined to both shaft ends of the element body of the filter medium. And it is comprised from the filter medium formed in the cylindrical shape.

  Moreover, the hollow part 27a comprised by the inner peripheral part of the filtration element 27 and the opening part 22a of the air derivation | leading-out part 22 are arrange | positioned substantially coaxially, and the air derivation | leading-out part 22 is the derivation | leading-out of air from the opening part 22a. It is bent toward the downstream side.

  Further, in the hollow portion 27 a of the filtration element 27, a fastener 25 for fixing the filtration element 27 in the casing 24 and fixing the filtration element 27 to the bottom side below the casing 24 is provided.

  The upper end portion of the fastener 25 is attached to the opening 22 a of the air outlet portion 22, and the lower end portion of the fastener 25 is attached to the partition plate 29 by screwing with the fastener 28. The fastener 25 includes a stay 30 formed by bending a belt-shaped steel material into a substantially U shape, a screw member 31 that can be screwed into the fastener 28, and a current plate 32. The stay 30 and the screw member 31 are: The filter element 27 is composed of a U-shaped support member having a known structure for suspending the filter element 27 on the casing 24.

  Note that the threaded portion of the screw member 31 and the fastener 28 that are screwed together is not limited to the combination of the male screw and the female screw such as a nut shown in FIG. 3, but is a combination of the screw member as the female screw and the fastener as the male screw. There may be.

  The stay 30 is composed of a pair of arm portions 30a extending substantially in the axial direction and a lower end portion 30b connecting the pair of arm portions 30a. The upper end side of the arm portion 30a is on the inner periphery of the air outlet portion 22. Joined and fixed by welding or the like. Further, one shaft end of the screw member 31 is engaged with the lower end 30 b of the stay 30.

  The rectifying plate 32 is made of a metal plate and is arranged coaxially with the filter element 27. Specifically, as shown in FIG. 2, the rectifying plate 32 is arranged so as to divide the inner periphery of the hollow portion 27 a into two. The rectifying plate 32 is arranged so as to bridge between the arm portions 30a, and forms a partition wall that bridges a predetermined axial range between the arm portions 30a.

  On the other hand, the casing 24 of the air cleaner 20 is provided with a secondary air discharge pipe 33. The secondary air discharge pipe 33 includes a cylindrical main body 33a connected to the secondary air outlet pipe 18, and a main body 33a. And a flange portion 33b fixed to the casing 24 of the air cleaner 20 by a screw 34. A communication hole 33c provided in the main body 33a communicates the secondary air outlet pipe 18 and the inside of the casing 24. is doing.

As shown in FIG. 5, the air introduction portion 21 is offset from the vertical central axis of the casing 24 so as to guide the air introduced into the casing 24 in one direction along the inner peripheral surface of the casing 24. The casing 24 is provided.
The secondary air discharge pipe 33 is installed on the upper part of the casing 24, and the secondary air discharge pipe 33 and the air introduction part 21 are separated from the flow direction of the air introduced into the casing 24. As shown in FIG. In the cyclone type air cleaner 20 of the present embodiment, the secondary air discharge pipe 33 is provided close to the air introduction part 21 and provided downstream of the air introduction part 21 in the air swirl direction.

  In the present embodiment, the air pump 17, the secondary air outlet pipe 18, and the air cleaner 20 constitute a secondary air supply device.

Next, the secondary air supply method of the engine 11 of this Embodiment is demonstrated.
In an overcab or the like where the engine 11 is installed below the driver's seat, the engine 11 is installed at a position close to the road surface, so water is sucked into the air cleaner 20 together with air during rainy weather or when running on a pool. There is a high possibility that Here, a description will be given of a secondary air supply method when traveling on rainy weather or traveling on a water pool.

  When the engine 11 is operated, air is sucked into the casing 24 under the negative pressure of the piston during the piston suction process. Water is introduced into the casing 24 from the air introduction portion 21 together with air during rainy weather traveling or a water pool traveling.

  The air containing water introduced into the casing 24 swirls between the inner peripheral surface of the casing 24 and the outer peripheral surface of the filter element 27, and between the inner peripheral surface of the casing 24 and the outer peripheral surface of the filter element 27. The relatively coarse dust and water contained in the air are pressed against the inner periphery of the casing 24 by the centrifugal force generated by the swirling flow of air, and the centrifugal force action of the swirling flow and the weight of the dust and water cause The dust and water descending along the inner periphery of the casing 24 are accumulated in the dust pan 26 at the bottom of the casing 24.

  On the other hand, since the air swirling spirally reaches the entire outer periphery of the filtration element 27, it is introduced from the entire outer periphery of the filtration element 27 toward the inner periphery, and merges into the hollow portion 27a. The air filtered by the element main body of the filter element 27 flows out toward the center of the hollow portion 27a.

  The filtered air merged in the hollow portion 27a flows toward the opening 22a of the air outlet 22 and is combusted in each cylinder of the engine 11 from the intake pipe connected to the air outlet 22 via the intake manifold and the intake port. Supplied to the chamber.

  On the other hand, since the secondary air discharge pipe 33 is provided close to the air introduction part 21 and downstream of the air introduction part 21 in the air swirl direction, as described above, the centrifugal force due to the swirl flow of air. As a result, the water contained in the air is pressed against the inner periphery of the casing 24, and the water falls along the inner periphery of the casing 24 by the centrifugal force action of the swirling flow and the weight of the water.

  Therefore, as shown in FIG. 5B, the air introduced into the casing 24 from the air introduction portion 21 and separated from the water is discharged from the secondary air discharge pipe 33 to the secondary air outlet pipe 18. The secondary air led out to the secondary air lead-out pipe 18 is sucked into the air pump 17, supplied from the air pump 17 to the secondary air supply pipe 16, and then supplied to the exhaust manifold 12 through the electromagnetic ASV 15 in an open state. .

  The secondary air supplied to the exhaust manifold 12 is mixed with the exhaust gas discharged from the combustion chamber of the engine. As a result, the oxidation reaction of unburned components such as hydrocarbon (HC) and carbon monoxide (CO) contained in the exhaust is promoted, and the catalyst is generated by the heat of combustion based on the oxidation reaction between the unburned components in the exhaust gas and air. The catalyst of the apparatus 14 can be activated early.

  As described above, in the present embodiment, the secondary air discharge pipe 33 for leading the secondary air from the casing 24 of the air cleaner 20 to the air pump 17 is provided, and the secondary air discharge pipe 33 is brought close to the air introduction unit 21 and the air Since it is provided on the downstream side of the air swirl direction with respect to the introduction part 21, air including water moves from the air introduction part 21 to the secondary air discharge pipe 33 during rainy weather traveling or a water pool running. In the meantime, water can be separated from the air. For this reason, only air can be led out from the secondary air discharge pipe 33 to the air pump 17 through the secondary air outlet pipe 18.

  Therefore, only secondary air can be supplied from the air pump 17 to the exhaust manifold 12 through the secondary air supply pipe 16, and water can be prevented from being supplied to the high-temperature catalyst in the catalyst device 14. it can. As a result, the catalyst can be prevented from being damaged, and the catalyst performance can be prevented from deteriorating.

  Further, in the present embodiment, the air cleaner 20 has a cylindrical filtration element 27, and the air introduced into the casing 24 from the air introduction part 21 via the secondary air discharge pipe 33 is transferred into the casing 24. The filter is guided along the circumferential surface so as to be filtered by the filter element 27, and is joined to a hollow part 27a formed inside the filter element 27 so that the filtered air is led out from the air outlet part 22. Therefore, the air introduced into the casing 24 from the air introduction portion 21 can be swung greatly along the inner peripheral surface of the casing 24 and discharged from the secondary air discharge pipe 33.

  Therefore, the air introduced into the casing 24 from the air introduction part 21 can be moved by a long distance between the air introduction part 21 and the secondary air discharge pipe 33. Therefore, water can be efficiently separated from the air introduced into the casing 24 while reducing the size of the air cleaner 20, and only air is supplied from the secondary air discharge pipe 33 to the air pump 17 through the secondary air outlet pipe 18. can do.

  In the present embodiment, since the secondary air discharge pipe 33 is provided above the casing 24, when the air moves from the air introduction part 21 to the secondary air discharge pipe 33, the water separated from the air is removed from the casing. It is possible to reliably prevent the water from being discharged from the secondary air discharge pipe 33 when it falls on the bottom surface of 24.

  That is, during the operation of the engine 11, there is a possibility that water that has fallen on the bottom surface of the casing 24 due to the negative pressure by the piston during the piston suction process may be sucked up. In the present embodiment, the secondary air discharge pipe 33 is provided. By providing it above the casing 24, it is possible to make it difficult for the water sucked from the bottom surface of the casing 24 to reach the secondary air discharge pipe 33, and reliably prevent water from being discharged from the secondary air discharge pipe 33. can do.

Further, the secondary air supply device for the internal combustion engine of the first embodiment is configured as shown in FIG. In FIG. 6, description is made by changing the reference numerals of the secondary air discharge pipe.

  In FIG. 6, a secondary air discharge pipe 41 includes a cylindrical main body 41a connected to the secondary air outlet pipe 18, and a flange portion (not shown) provided on the main body 41a and fixed to the casing 24 of the air cleaner 20 by screws. The communication hole 41b provided in the main body 41a communicates the secondary air outlet pipe 18 and the casing 24.

  The main body 41a includes a protruding portion 41c. The protruding portion 41c protrudes inward of the casing 24 from the inner peripheral surface of the casing 24, and a communication hole 41b is formed inside the protruding portion 41c. . That is, the main body 41 a is an integral type having a communication hole 41 b inside, and the protruding portion 41 c protrudes from the inner peripheral surface of the casing 24 to the inside of the casing 24.

  In the present embodiment, as shown by B1 and B2 in FIG. 6, it is possible to create an air flow that causes the air swirling on the inner peripheral surface of the casing 24 to collide with the protruding portion 41c and be separated vertically. For this reason, if water has reached the secondary air discharge pipe 41 together with the air sucked into the casing 24 from the air introduction part 21, the wall surface of the protrusion 41c causes water to enter the protrusion 41c. Can be reduced. For this reason, it is possible to more reliably prevent water from being discharged from the secondary air discharge pipe 33 to the secondary air outlet pipe 18.

(Second Embodiment)
FIG. 7 is a view showing a second embodiment of the secondary air supply device for an internal combustion engine according to the present invention, and the configuration of the secondary air discharge pipe is only different from that of the first embodiment. The same components as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  In FIG. 7, the secondary air discharge pipe 45 includes a cylindrical main body 45 a connected to the secondary air outlet pipe 18, and a flange portion 45 b provided on the main body 45 a and fixed to the casing 24 of the air cleaner 20 by screws 46. The communication hole 45c provided in the inside of the main body 45a communicates the secondary air outlet pipe 18 and the inside of the casing 24.

  The main body 45a is provided with a protrusion 45e. The protrusion 45e protrudes inward of the casing 24 from the inner peripheral surface of the casing 24, and a communication hole 45c is formed in the protrusion 45e. . That is, the main body 45 a is an integral type having a communication hole 45 c inside, and the protruding portion 45 e protrudes from the inner peripheral surface of the casing 24 to the inside of the casing 24.

  Moreover, the communication hole 45c of the protrusion part 45a is diameter-expanded toward the inner side of the casing 24 from the inner peripheral surface of the casing 24, and the protrusion part 45a is formed in the trumpet shape.

In the present embodiment, similarly to the first embodiment, it is possible to create an air flow that causes the air swirling on the inner peripheral surface of the casing 24 to collide with the protrusion 45e and separate it up and down. For this reason, if water reaches the secondary air discharge pipe 45 together with the air sucked into the casing 24 from the air introduction part 21, the water to the inside of the protrusion 45e is caused by the wall surface of the protrusion 45e. Can be reduced.

  In addition, since the diameter of the communication hole 45c of the protrusion 45e is expanded from the inner peripheral surface of the casing 24 toward the inside of the casing 24, the flow path of the communication hole 45c on the upstream side in the secondary air outlet direction is reduced. It can be made wider than the flow path of the communication hole 45c on the downstream side in the lead-out direction.

  For this reason, the flow rate of the air introduced into the communication hole 45c of the protrusion 45e on the upstream side in the outlet direction of the secondary air can be reduced, and it is difficult to introduce water together with the air into the secondary air discharge pipe 45, It is possible to more reliably prevent water from being led out from the secondary air discharge pipe 45 to the secondary air outlet pipe 18.

( Third embodiment)
8 and 9 are views showing a third embodiment of the secondary air supply device for an internal combustion engine according to the present invention. The present embodiment is provided at the position of the cyclone type air cleaner 20, and the configuration of the air cleaner is different from that of the first embodiment. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted, and description will be made with reference to FIG.

  In FIG. 8, the air cleaner 51 includes a casing 52 as a main body having an air introduction part 53 and an air lead-out part 54, and a rectangular filter element 55 accommodated in the casing 52.

  The casing 52 is formed in a rectangular shape, and the air introduction portion 53 and the air lead-out portion 54 are attached to the front and rear ends of the casing 52 and installed in a straight line.

The air outlet 54 is connected to an intake pipe (not shown), and the intake pipe communicates with a combustion chamber of each cylinder of the engine 11 via an intake manifold and an exhaust port (not shown).
Moreover, the casing 52 of this Embodiment is shape | molded from resin materials, such as metal materials, such as a steel plate, or a polypropylene. The filter element 55 is formed in a rectangular shape, and is composed of a filter medium in which filter paper or the like is formed in a wave shape.

  On the other hand, the casing 52 of the air cleaner 51 is provided with a secondary air discharge pipe 56. The secondary air discharge pipe 56 includes a cylindrical main body 56a connected to the secondary air outlet pipe 18, and a main body 56a. And a flange portion 56b fixed to the casing 52 of the air cleaner 51 by a screw 57. A communication hole 56c provided in the main body 56a communicates the secondary air outlet pipe 18 and the inside of the casing 52. is doing.

  The secondary air discharge pipe 56 is installed in the upper part of the casing 52, and the secondary air discharge pipe 56 is separated from the air introduction part 53 with respect to the air flow direction in the casing 52. Is provided. Further, the main body 56 a of the secondary air discharge pipe 56 extends in a direction orthogonal to a straight line connecting the air introduction part 53 and the air lead-out part 54.

  In the present embodiment, the air pump 17, the secondary air outlet pipe 18, and the air cleaner 51 constitute a secondary air supply device.

Next, the secondary air supply method of the engine 11 of this Embodiment is demonstrated.
In an overcab or the like where the engine 11 is installed below the driver's seat, the engine 11 is installed at a position close to the road surface, so water is sucked into the air cleaner 20 together with air during rainy weather or when running on a pool. There is a high possibility that Here, a description will be given of a secondary air supply method when traveling on rainy weather or traveling on a water pool.

  When the engine 11 is operated, air is sucked into the casing 52 under the negative pressure of the piston during the piston suction process. Water is introduced into the casing 52 from the air introduction portion 53 together with air during rainy weather traveling or a water pool traveling.

  Air or water introduced into the casing 52 is filtered through the intake manifold and the intake port from the intake pipe connected to the air outlet 54 after the relatively coarse dust and water are filtered by the filter element 55. 11 is supplied to the combustion chamber of each cylinder.

  On the other hand, since the secondary air discharge pipe 56 is provided at a position separated from the air introduction part 53, the water that has not been filtered by the filter element 55 has moved downstream in the air flow direction with respect to the filter element 55. Even in such a case, the momentum of the water is weakened by the impact when it collides with the filter element 55, and it falls to the bottom surface of the casing 52 by its own weight before moving from the filter element 55 to the secondary air discharge pipe 56. To do.

  For this reason, the air introduced into the casing 52 from the air introduction part 53 and separated from the water is discharged from the secondary air discharge pipe 56 to the secondary air outlet pipe 18. The secondary air led out to the secondary air lead-out pipe 18 is sucked into the air pump 17, supplied from the air pump 17 to the secondary air supply pipe 16, and then supplied to the exhaust manifold 12 through the electromagnetic ASV 15 in an open state. .

  The secondary air supplied to the exhaust manifold 12 is mixed with the exhaust gas discharged from the combustion chamber of the engine. As a result, the oxidation reaction of unburned components such as hydrocarbon (HC) and carbon monoxide (CO) contained in the exhaust is promoted, and the catalyst is generated by the heat of combustion based on the oxidation reaction between the unburned components in the exhaust gas and air. The catalyst of the apparatus 14 can be activated early.

  As described above, in the present embodiment, the air cleaner 51 and the air pump 17 are connected by the secondary air outlet pipe 18, and the secondary air discharge pipe 56 connected to the secondary air outlet pipe 18 is provided in the casing 52 of the air cleaner 51. The secondary air discharge pipe 56 is brought close to the air introduction part 53, and the secondary air discharge pipe 56 and the air introduction part 53 are separated from each other in the air flow direction. Sometimes, water introduced into the air introduction part 53 together with air can be separated from the air while moving from the air introduction part 53 to the secondary air discharge pipe 56. For this reason, only air can be led out from the secondary air discharge pipe 33 to the air pump 17 through the secondary air outlet pipe 18.

  Therefore, only secondary air can be supplied from the air pump 17 to the exhaust manifold 12 through the secondary air supply pipe 16, and water can be prevented from being supplied to the high-temperature catalyst in the catalyst device 14. it can. As a result, the catalyst can be prevented from being damaged, and the catalyst performance can be prevented from deteriorating.

  In the present embodiment, since the secondary air discharge pipe 56 is provided above the casing 52, when the air moves from the air introduction part 53 to the secondary air discharge pipe 56, the water separated from the air is removed from the casing. It is possible to reliably prevent this water from being discharged from the secondary air discharge pipe 56 when it falls to the bottom surface of 52.

  In the present embodiment, a part of the secondary air discharge pipe may be protruded into the casing 52 as shown in FIG. In FIG. 9, the secondary air discharge pipe 60 includes a cylindrical main body 60 a connected to the secondary air outlet pipe 18, and a flange portion 60 b provided on the main body 60 a and fixed to the casing 24 of the air cleaner 20 by screws 61. The communication hole 60c provided in the inside of the main body 60a communicates the secondary air outlet pipe 18 and the inside of the casing 52.

  The main body 60a is provided with a protrusion 60e. The protrusion 60e protrudes inward of the casing 52 from the inner peripheral surface of the casing 52, and a communication hole 60c is formed in the protrusion 60e. . That is, the main body 60 a is an integral type having a communication hole 60 c inside, and the protruding portion 60 e protrudes from the inner peripheral surface of the casing 52 to the inside of the casing 24.

  In this way, when the water that has passed through the filter element 55 reaches the secondary air discharge pipe 60, the amount of water entrained inside the protrusion 60e is reduced by the wall surface of the protrusion 60e. Can do. For this reason, it is possible to more reliably prevent water from being discharged from the secondary air discharge pipe 60 to the secondary air outlet pipe 18.

  Further, the communication hole 60 c of the protrusion 60 e may be expanded from the inner peripheral surface of the casing 52 toward the inside of the casing 52. In this case, since the flow path of the communication hole 60c on the upstream side in the lead-out direction of the secondary air can be made wider than the flow path of the communication hole 60c on the downstream side in the lead-out direction, the protrusion on the upstream side in the lead-out direction The flow rate of the air introduced into the communication hole 60c of the portion 60e can be slowed, and it is difficult to introduce water together with the air into the secondary air discharge pipe 60, so that the water is discharged from the secondary air discharge pipe 60 to the secondary air outlet pipe. It is possible to more reliably prevent the discharge to 18.

  In addition, the embodiment disclosed this time is illustrative in all respects and is not limited to this embodiment. The scope of the present invention is shown not by the above description of the embodiments but by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

  As described above, the secondary air supply device for an internal combustion engine according to the present invention can prevent water from entering and damaging the catalyst, and can prevent deterioration of the catalyst performance. It is useful as a secondary air supply device for an internal combustion engine in which secondary air is supplied from an air cleaner upstream of the catalyst provided in the exhaust pipe.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows 1st Embodiment of the secondary air supply apparatus of the internal combustion engine which concerns on this invention, and is a schematic block diagram of a secondary air supply apparatus. It is a figure which shows 1st Embodiment of the secondary air supply apparatus of the internal combustion engine which concerns on this invention, and is a top view of an air cleaner. FIG. 3 is a cross-sectional view taken along arrow AA in FIG. 2. It is a figure which shows 1st Embodiment of the secondary air supply apparatus of the internal combustion engine which concerns on this invention, and is a schematic perspective view of an air cleaner. It is a figure which shows 1st Embodiment of the secondary air supply apparatus of the internal combustion engine which concerns on this invention, and is a figure which shows the flow of the air introduce | transduced in the casing from the air introduction part. It is a figure which shows 1st Embodiment of the secondary air supply apparatus of the internal combustion engine which concerns on this invention, and is a perspective view which shows the shape of a secondary air discharge pipe. It is a figure which shows 2nd Embodiment of the secondary air supply apparatus of the internal combustion engine which concerns on this invention, (a) is a perspective view which shows the shape of a secondary air discharge pipe, (b) of a secondary air discharge pipe It is sectional drawing. It is a figure which shows 3rd Embodiment of the secondary air supply apparatus of the internal combustion engine which concerns on this invention, (a) is a top view of an air cleaner, (b) is XX direction sectional drawing of the figure (a). It is. It is a figure which shows 3rd Embodiment of the secondary air supply apparatus of the internal combustion engine which concerns on this invention, and is a top view of the air cleaner which has the secondary air discharge pipe of another shape. It is a schematic block diagram of the conventional secondary air supply apparatus.

Explanation of symbols

11 Engine (Internal combustion engine)
13 Exhaust pipe 14 Catalytic device 16 Secondary air supply pipe 17 Air pump (supply pump)
18 Secondary air outlet pipe 20, 51 Air cleaner 21, 53 Air inlet part 22, 54 Air outlet part 24, 52 Casing (main body)
27, 55 Filtration element 27a Hollow part 33, 41, 45, 56, 60 Secondary air discharge pipe 41b, 45c, 56c, 60c Communication hole 41c, 45e, 60e Protruding part

Claims (4)

A secondary air supply pipe connected at one end to the upstream side of the catalyst provided in the exhaust pipe, and connected to the other end of the secondary air supply pipe, and the catalyst via the secondary air supply pipe A supply pump that supplies secondary air to the upstream side, a cylindrical main body provided with an air introduction unit that introduces air and an air extraction unit that derives air, and the air introduction unit and the air extraction unit. An air cleaner having a filtering element provided in the main body so as to be located between
A secondary air supply device for an internal combustion engine configured to swirl the air introduced into the main body from the air introduction portion along the inner peripheral surface of the main body ,
A secondary air outlet pipe having one end connected to the supply pump, and the other end of the secondary air outlet pipe are connected to the main body, and secondary air is supplied from the main body to the supply pump. And a secondary air discharge pipe for discharging
The secondary air discharge pipe, protrudes inwardly of the body from the inner circumferential surface of the body, has a protrusion that air swirling collides the inner peripheral surface of said body, said projecting portion, the two A communication hole communicating with the inside of the main body and the secondary air outlet pipe;
The air introduction part is provided in the main body so as to be offset from a vertical central axis of the main body so as to guide the air introduced into the main body in one direction along the inner peripheral surface of the main body. A secondary air supply device for an internal combustion engine. The air cleaner has a cylindrical filtering element as the filtering element, and the air introduced into the main body from the air introducing portion is swung along the inner peripheral surface of the main body and filtered by the filtering element. And is joined to a hollow portion formed inside the filtration element so as to derive the filtered air from the air outlet portion,
2. The secondary of the internal combustion engine according to claim 1, wherein the secondary air discharge pipe is provided in the vicinity of the air introduction portion and downstream of the air introduction portion in the swirl direction of air. Air supply device.   The secondary air supply device for an internal combustion engine according to claim 1 or 2, wherein the secondary air discharge pipe is provided above the main body.   The said communicating hole of the said protrusion part is expanded toward the inner side of the said main body from the internal peripheral surface of the said main body, The claim of any one of Claim 1 thru | or 3 characterized by the above-mentioned. A secondary air supply device for an internal combustion engine.

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