Claims
- 1. An apparatus for reducing the emissions of Nox from a lean-burn engine having associated therewith an exhaust system having an exhaust passage leading to a SCR reactor effective for selective catalytic Nox reduction, comprising:a pyrolysis chamber for pyrolizing urea fed as an aqueous solution including heated internal surfaces and having openings therein to permit discharge of gases generated by pyrolysis of urea and vaporization of water; means for passing the gases generated by pyrolysis into the exhaust passage containing exhaust gases; means for passing the exhaust gases containing the gases generated by pyrolysis to a SCR reactor; spray means capable of spraying the urea solution into the pyrolysis chamber; and said spray means comprising an injector nozzle having associated lines for feeding the solution to the nozzle and returning solution not discharged from the nozzle.
- 2. An apparatus according to claim 1, which further comprises:a heat exchanger to transfer heat from the exhaust gases to the pyrolysis chamber.
- 3. An apparatus according to claim 1, which further comprises:an auxiliary heater to heat the pyrolysis chamber.
Parent Case Info
This application is a divisional of a application Ser. No. 08/854,831, filed May 12, 1997, now U.S. Pat. No. 5,968,464.
US Referenced Citations (12)
Foreign Referenced Citations (6)
Number |
Date |
Country |
1100292 |
May 1981 |
CA |
0 210 392 |
Jun 1986 |
EP |
0 487 886 |
Jun 1993 |
EP |
0 615 777 |
Feb 1994 |
EP |
9007561 |
Jul 1990 |
WO |
9701387 |
Jan 1997 |
WO |
Non-Patent Literature Citations (1)
Entry |
Hultermans, R.J.; “Selective Catalytic Reduction of NOx from diesel engine exhaust using injection of urea”; Ph.D. thesis, Technische Universiteit Delft, Sep. 1995. (A copy of this reference was supplied in the original application, Ser. No. 08,854,831. If a copy is needed we will order one for the Examiner.). |