Secondary air supply device for internal combustion engine

Abstract

An air cleaner has: a main body that is provided with an air introduction part and an air lead-out part; a filter element is provided within the main body and is positioned between the air introduction part and the air lead-out part; and a secondary air discharge pipe that is provided in the main body and positioned apart from the air introduction port in relation to the direction of air flow within the main body.

1 . A secondary air supply device for an internal combustion engine, comprising:
 an exhaust pipe;   a catalyst provided in the exhaust pipe;   a secondary air supply pipe, one end of which is connected to the exhaust pipe at a position upstream of the catalyst;   a supply pump, connected to the other end of the secondary air supply pipe, that supplies secondary air via the secondary air supply pipe to the exhaust pipe;   an air cleaner that includes a main body provided with an air introduction port for introducing air, an air lead-out port for leading the air out, and a filter element, provided within the main body, that is positioned between the air introduction port and the air lead-out port;   a secondary air lead-out pipe, one end of which is connected to the supply pump and the other end of which is connected to the main body; and   a secondary air discharge pipe, which is provided in the main body and discharges the secondary air from the main body to the supply pump via the secondary air lead-out pipe, wherein   the secondary air discharge pipe is positioned apart from the air introduction port in the main body in relation to a direction of air flow within the main body.   
   
   
       2 . The secondary air supply device according to  claim 1 , wherein:
 the filter element is in the shape of a hollow cylinder, which defines a hollow core;   the air lead-out part is communicated with the hollow core;   air introduced from the air introduction port of the air cleaner into the main body swirls along an inner peripheral surface of the main body and then filtered by the filter element before being led out through the air lead-out part via the hollow core; and   the secondary air discharge pipe is provided near the air introduction port on a downstream side in the air swirling direction with respect to the air introduction port.   
   
   
       3 . The secondary air supply device according to  claim 1 , wherein the secondary air discharge pipe is provided in an upper part of the main body. 
   
   
       4 . The secondary air supply device according to  claim 1 , wherein:
 the secondary air discharge pipe has a projection that projects inward of the main body from the inner peripheral surface of the main body; and   the projection has a communication hole that communicates the secondary air lead-out pipe with the inside of the main body.   
   
   
       5 . The secondary air supply device according to  claim 4 , wherein the communication hole of the projection is configured such that a diameter of the communication hole increases from the inner peripheral surface of the main body toward the inside of the main body. 
   
   
       6 . The secondary air supply device according to  claim 1 , wherein:
 the main body is a substantially rectangular hollow member;   the filter element is formed into a substantially rectangular shape; and   the secondary air discharge pipe is positioned apart from the filter element and provided downstream of the filter element.   
   
   
       7 . An air cleaner, comprising:
 a main body, which is provided with an air introduction port for introducing air and a first air lead-out port for leading the air out;   a filter element, which is provided within the main body and positioned between the air introduction port and the first air lead-out port; and   a second air lead-out port, which is provided in the main body and positioned apart from the air introduction port in relation to a direction of air flow within the main body.