Sampling tube for improved exhaust gas flow to exhaust sensor

Abstract

An exhaust assembly for a vehicle includes an exhaust pipe through which an exhaust gas flows substantially in a first direction. The exhaust pipe includes a central region. The assembly also includes a sensor in fluid communication with the exhaust pipe and an elongated tube extending from a first end toward a second end and disposed at least partially within the exhaust pipe. The first end of the tube receives at least a portion of the sensor. The tube includes an inlet opening and an outlet opening. The inlet opening generally faces the exhaust gas flowing within the central region in the first direction so that flow of the exhaust gas in the central region substantially directly enters the inlet opening. The tube directs the exhaust gas within the tube toward the sensor, and the exhaust gas within the tube flows out of the tube through the outlet opening.

1 . An exhaust assembly for a vehicle comprising:
 an exhaust pipe through which an exhaust gas flows substantially in a first direction, the exhaust pipe including a central region;   a sensor in fluid communication with the exhaust pipe; and   an elongated tube extending from a first end toward a second end and disposed at least partially within the exhaust pipe, the first end of the tube receiving at least a portion of the sensor, the tube including an inlet opening and an outlet opening, the inlet opening generally facing the exhaust gas flowing within the central region in the first direction so that flow of the exhaust gas in the central region substantially directly enters the inlet opening, the tube directs the exhaust gas within the tube toward the sensor, and the exhaust gas within the tube flows out of the tube through the outlet opening.   
     
     
         2 . The exhaust assembly of  claim 1 , further comprising a catalyst member that is disposed in the exhaust pipe, the catalyst member being disposed upstream of the sensor and the tube. 
     
     
         3 . The exhaust assembly of  claim 1 , wherein both the sensor and the first end of the tube are disposed within the exhaust pipe. 
     
     
         4 . The exhaust assembly of  claim 3 , wherein the first end of the tube and the sensor are disposed adjacent an inner wall surface of the exhaust pipe. 
     
     
         5 . The exhaust assembly of  claim 1 , wherein the tube is substantially straight. 
     
     
         6 . The exhaust assembly of  claim 5 , wherein a tube axis of the tube is disposed at an angle relative to the central region of the exhaust pipe, the angle being at least approximately eighty degrees (80°) and at most approximately ninety degrees) (90°. 
     
     
         7 . The exhaust assembly of  claim 6 , wherein the tube axis is approximately perpendicular to the central region of the exhaust pipe. 
     
     
         8 . The exhaust assembly of  claim 1 , wherein at least one of the inlet opening and outlet opening has a non-circular shape. 
     
     
         9 . The exhaust assembly of  claim 1 , wherein the exhaust pipe includes an opening, each of the sensor and the tube extending into the exhaust pipe through the opening, the tube and the sensor each being joined to the exhaust pipe. 
     
     
         10 . The exhaust assembly of  claim 9 , further comprising a boss that is fixed to the tube, the boss including a threaded opening, the sensor being threadably attached to the boss. 
     
     
         11 . The exhaust assembly of  claim 10 , wherein at least one of the tube and the boss is welded to the exhaust pipe. 
     
     
         12 . The exhaust assembly of  claim 1 , wherein the first end of the tube is joined to the exhaust pipe and the second end is disposed generally within the central region of the exhaust pipe. 
     
     
         13 . The exhaust assembly of  claim 1 , wherein the inlet opening and the outlet opening are disposed on opposite sides of a tube axis of the tube. 
     
     
         14 . The exhaust assembly of  claim 1 , wherein the sensor is an oxygen sensor. 
     
     
         15 . The exhaust assembly of  claim 1 , wherein the second end of the tube is closed. 
     
     
         16 . The exhaust assembly of  claim 1 , wherein the tube includes a circular cross sectional shape. 
     
     
         17 . The exhaust assembly of  claim 1 , wherein the exhaust pipe includes a pipe axis that extends through the central region, and wherein the pipe axis extends through the inlet opening of the tube. 
     
     
         18 . The exhaust assembly of  claim 1 , wherein a wall thickness of the tube remains substantially constant along a length of the tube. 
     
     
         19 . The exhaust assembly of  claim 1 , wherein the tube includes at least one of stainless steel and an austenitic nickel-chromium-based material. 
     
     
         20 . An exhaust assembly for a vehicle comprising:
 an exhaust pipe through which an exhaust gas flows, the exhaust pipe having a central axis and an inner wall surface, the exhaust pipe including an opening;   a catalyst member disposed in the exhaust pipe;   an oxygen sensor that is fixed relative to the exhaust pipe, the sensor being disposed adjacent the inner wall surface of the exhaust pipe, the oxygen sensor disposed downstream of the catalyst member; and   a tube that is hollow and that has a substantially right circular cylindrical shape so as to include a first end, a second end, and a substantially straight tube axis, the tube also including a side wall that extends along the tube axis, the second end including an end wall that closes off the second end, the first end being open to receive the sensor, the tube additionally including an inlet opening in the side wall adjacent the second end and an outlet opening in the side wall adjacent the first end, the inlet opening and the outlet opening being disposed on opposite sides of the tube axis, the tube extending through the opening in the exhaust pipe such that both the tube and the sensor extend into the exhaust pipe, the tube being fixed to the exhaust pipe to be disposed downstream from the catalyst member, the tube being cantilevered within the exhaust pipe, the central axis of the exhaust pipe extending through the inlet opening, the tube directing flow of the exhaust gas into the inlet opening, toward the sensor, and out of the tube through the outlet opening.