Ex parte Kharas et al.

Board of Patent Appeals and Interferences

Dec 30, 1997

07990216 (B.P.A.I. Dec. 30, 1997)

Application for patent filed December 14, 1992. 1
THIS OPINION WAS NOT WRITTEN FOR PUBLICATION
The opinion in support of the decision being entered
today (1) was not written for publication in a law
journal and (2) is not binding precedent of the
Board.
Paper No. 17
UNITED STATES PATENT AND TRADEMARK OFFICE
____________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________
Ex parte KARL C. KHARAS, MICHAEL G. HENK and HEINZ J. ROBOTA
____________
Appeal No. 95-4932
Application No. 07/990,2161
____________
ON BRIEF
____________
Before SOFOCLEOUS, CAROFF and WEIFFENBACH, Administrative
Patent Judges.
CAROFF, Administrative Patent Judge.
DECISION ON APPEAL
This decision on appeal relates to the final rejection of
claims 1 and 3-12, all the claims remaining in the involved
application.
The claims relate to a multi-component catalyst for
removing carbon monoxide, hydrocarbons, and especially
nitrogen oxides (NO ) from the exhaust gases of a lean-burnx
Appeal No. 95-4932
Application No. 07/990,216
2
internal combustion engine operating under conditions where
oxygen is present in excess of the stoichiometric quantity.
Claims 1 and 4, the sole independent claims on appeal, are
representative:
1. A multicomponent catalyst for removing carbon
monoxide, hydrocarbons, and nitrogen oxides from the exhaust
gases of a lean burn internal combustion engine operating with
an air-fuel ratio above about 18/1 comprising at least two
components, each of said components characterized by being
able to reduce nitrogen oxides within a temperature range
beginning near the onset of activity for oxidation of the
carbon monoxide, hydrocarbons, and hydrogen by oxygen and
ending at a higher temperature, said components being disposed
in reverse order of their temperature range for nitrogen
oxides reduction so that the component which reduces nitrogen
oxides at the highest temperature range is exposed first to
the exhaust gases and with the component which reduces
nitrogen oxides at the lowest temperature range being exposed
last to the exhaust gases.
4. A multicomponent catalyst for removing carbon
monoxide, hydrocarbons, and nitrogen oxides from the exhaust
gases of an internal combustion engine containing oxygen in
excess of the stoichiometric quantity needed for complete
combustion comprising at least three components exposed in
sequence to the exhaust gases;
(a) a first component capable of reducing nitrogen
oxides at temperatures above about 475