Exhaust system for an engine

Abstract

An exhaust system for an engine including an exhaust passage with an expanding flow area and at least an opening for transferring air external to within the exhaust passage to cool the exhaust, for example due to particulate filter regeneration.

1 - 24 . (canceled) 
     
     
         25 . An exhaust passage for an engine, comprising:
 a first exhaust passage;   a second exhaust passage communicatively coupled to the first exhaust passage at an interface end of the first exhaust passage, the second exhaust passage including a downstream tailpipe exit leading directly to the external environment, the second exhaust passage arranged downstream of the first exhaust passage, the second exhaust passage outwardly flared toward the tailpipe exit with an increasing cross-sectional area, the outward flare at the tailpipe exit outwardly angled;   at least a peripheral opening defined by a wall surface of the exhaust passage, the peripheral opening radially arranged around the exhaust passage for transferring air external the exhaust passage to within the exhaust passage, wherein an angled portion of the wall surface of the exhaust passage at the radial opening is only inwardly angled at an upstream end of the opening.   
     
     
         26 . The exhaust passage of  claim 25 , further comprising a particulate filter communicatively coupled to the first exhaust passage. 
     
     
         27 . The exhaust passage of  claim 25 , further comprising a particulate filter coupled upstream of the peripheral opening. 
     
     
         28 . The exhaust passage of  claim 25 , wherein the second exhaust passage comprises only a single pipe coupled to the first exhaust passage. 
     
     
         29 . The exhaust passage of  claim 28 , wherein cross sections of the single pipe comprising the second exhaust passage are circular. 
     
     
         30 . The exhaust passage of  claim 25 , further comprising a diesel oxidation catalyst communicatively coupled to the exhaust passage. 
     
     
         31 . The exhaust passage of  claim 25 , wherein the interface end of the first exhaust passage is not outwardly flared. 
     
     
         32 . An exhaust passage for a vehicle having a diesel engine, comprising:
 a first exhaust passage;   a second exhaust passage communicatively coupled to the first exhaust passage at an interface end of the first exhaust passage, the second exhaust passage including a downstream tailpipe exit leading directly to the external environment, the second exhaust passage arranged downstream of the first exhaust passage, the second exhaust passage outwardly flared toward the tailpipe exit with an increasing cross-sectional area, the outward flare at the tailpipe exit outwardly angled;   at least a peripheral opening defined by a wall surface of the exhaust passage, the peripheral opening radially arranged around the exhaust passage for transferring air external the exhaust passage to within the exhaust passage, wherein an angled portion of the wall surface of the exhaust passage at the radial opening is only inwardly angled at an upstream end of the opening;   a particulate filter communicatively coupled to the exhaust passage upstream of the first exhaust passage; and   a diesel oxidation catalyst communicatively coupled to the exhaust passage upstream of the diesel particulate filter.   
     
     
         33 . The exhaust passage of  claim 32 , wherein the second exhaust passage comprises a single pipe coupled to the first exhaust passage. 
     
     
         34 . The exhaust passage of  claim 32 , wherein the first and second passages are positioned on an underside of a pickup truck, the tailpipe exit directing exhaust gasses out of the tailpipe at a rear-ward angle with respect to a longitudinal axis of the truck. 
     
     
         35 . The exhaust passage of  claim 34 , wherein the exhaust passage includes a plurality of bends to accommodate a shape of the pickup truck. 
     
     
         36 . The exhaust passage of  claim 34 , further comprising a plurality of hangers securing the exhaust passage to an underside of the pickup truck. 
     
     
         37 . The exhaust passage of  claim 32 , wherein the first and second exhaust passages are positioned beneath a rear axle of the vehicle, the vehicle being a pickup truck. 
     
     
         38 . The exhaust passage of  claim 37 , wherein the exhaust passage includes a bend towards a rear wheel of the vehicle upstream of the first exhaust passage. 
     
     
         39 . The exhaust passage of  claim 32 , wherein the vehicle is a pickup truck. 
     
     
         40 . The exhaust passage of  claim 32 , wherein the interface end of the first exhaust passage is not outwardly flared. 
     
     
         41 . An exhaust passage for a pickup truck having a diesel engine, comprising:
 a first exhaust passage;   a second exhaust passage communicatively coupled to the first exhaust passage at an interface end of the first exhaust passage, the second exhaust passage including a downstream tailpipe exit leading directly to the external environment, the second exhaust passage arranged downstream of the first exhaust passage, the second exhaust passage outwardly flared toward the tailpipe exit with an increasing cross-sectional area, the outward flare at the tailpipe exit outwardly angled, the second exhaust passage comprising a single pipe coupled to the first exhaust passage;   at least a peripheral opening defined by a wall surface of the exhaust passage, the peripheral opening radially arranged around the exhaust passage for transferring air external the exhaust passage to within the exhaust passage, wherein an angled portion of the wall surface of the exhaust passage at the radial opening is only inwardly angled at anupstream end of the opening;   a particulate filter communicatively coupled to the exhaust passage upstream of the first exhaust passage;   a diesel oxidation catalyst communicatively coupled to the exhaust passage upstream of the diesel particulate filter; and   a hanger coupled to the exhaust passage upstream of the peripheral opening, the hanger coupling the exhaust passage to an underside of the pickup truck.   
     
     
         42 . The exhaust passage of  claim 41 , wherein the exhaust passage includes a plurality of bends to accommodate a shape of the pickup truck, and a plurality of hangers securing the exhaust passage to the underside of the truck, and wherein the first and second exhaust passages are positioned beneath a rear axle of the truck. 
     
     
         43 . The exhaust passage of  claim 41 , wherein the exhaust passage positioned at an underside of the pickup truck and includes a bend towards a rear wheel of the truck upstream of the first exhaust passage. 
     
     
         44 . The exhaust passage of  claim 41 , wherein the interface end of the first exhaust passage is not outwardly flared.