EXHAUST EMISSION CONTROL DEVICE

• US 20100257850A1
• Filed: 11/20/2008
• Published: 10/14/2010
• Est. Priority Date: 11/21/2007
• Status: Active Grant

• Current Assignee: Tokyo Roki Co., Ltd., HINO Motors Limited (Toyota Motor Corporation)
• Original Assignee: Tokyo Roki Co., Ltd., HINO Motors Limited (Toyota Motor Corporation)
• Inventors: Shimizu, Tsutomu, Kowada, Minoru
• Granted Patent: US 8,353,152 B2
• Time in Patent Office: Days
• US Class Current: 60/297
• CPC Class Codes: F01N 13/011 having two or more purifying devices arranged in parallel
• CPC Class Codes: F01N 13/02 having two or more separate silencers in series
• CPC Class Codes: F01N 13/08 Other arrangements or adaptations of exhaust conduits pipes, joints or supports therefor in general F16L; collecting or removing exhaust gases of vehicle engines in workshops B08B15/00, on highways E01C1/005
• CPC Class Codes: F01N 13/141 Double-walled exhaust pipes or housings
• CPC Class Codes: F01N 2470/00 Structure or shape of gas passages, pipes or tubes
• CPC Class Codes: F01N 2610/02 the substance being ammonia or urea
• CPC Class Codes: F01N 2610/1453 Sprayers or atomisers; Arrangement thereof in the exhaust apparatus
• CPC Class Codes: F01N 3/2066 Selective catalytic reduction [SCR]
• CPC Class Codes: F01N 3/28 Construction of catalytic reactors
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

An exhaust emission control device is provided which can reliably absorb thermal expansion difference between a particulate filter and a selective reduction catalyst without causing deposition of urea.

The exhaust emission control device has a particulate filter 5 and a selective reduction catalyst arranged in parallel with each other in such a manner that entry ends of them are directed to the same direction, an S-shaped communication passage 9 being provided for introduction of the exhaust gas 3 discharged from the discharge end of the particulate filter into an entry end of the adjacent selective reduction catalyst through turndown, urea water being addible upstream of the communication passage 9. A mixing pipe 10 providing a straight portion of the communication passage 9 is provided at its intermediate portion with a double-pipe portion 18 constituted by overlapped inner and outer pipes 16 and 17 which are relatively stretchable and retractable, the outer pipe 17 having a terminal end secured to an outer periphery of the inner pipe 16 and being provided at an appropriate position with an axially expansible and contractible bellows 19, a sealing ring 20 being fitted over an outer periphery of a terminal end of the inner pipe 16.

Claims

1. An exhaust emission control device comprising a particulate filter, a selective reduction catalyst capable of selectively reacting NO_x with ammonia even in the presence of oxygen, said selective reduction catalyst being arranged downstream of and in parallel with said particulate filter such that entry ends thereof are directed to the same direction, and an S-shaped communication passage for introduction of exhaust gas from a discharge end of the particulate filter to the entry end of the selective reduction catalyst through turndown, urea water being addible upstream of said communication passage, wherein a straight portion extending axially of the particulate filter and of the selective reduction catalyst in the communication passage is constituted at an intermediate portion thereof by a double-pipe portion comprising overlapped inner and outer pipes which are relatively stretchable and retractable and one and the other of which provide upstream and downstream ducts of said straight portion, respectively, said outer pipe in said double-pipe portion having a terminal end secured to an outer periphery of the inner pipe and being formed at an appropriate position with an axially expansible and contractible bellows, a sealing ring being fitted over the outer periphery at a terminal end of the inner pipe to slidably abut against an inner periphery of the outer pipe so as to prevent intrusion of the exhaust gas.