Appeal 2006-3268
Application 10/479,696
have an influence on the pressure regulation.” Device claim 21 further
recites “the pressure recording element includes a pressure sensor.”
Method claim 26 recites, in relevant part, “recording pressure changes
at a side of the metering device facing the catalytic converter system, the
pressure changes having an influence on the pressure regulation.”
Regarding claims 13 and 26, the Examiner found that Hofmann’s
control valve 50 interacts with pressure P2 (i.e., pressure recording element
according to the Examiner) to control the operation of valve 50 (Answer 3-
4). Regarding claim 21, the Examiner stated that Hofmann discloses a
pressure sensor P2 as shown in Figure 1 (Answer 4).
Regarding claims 13 and 26, Appellant argues that control valve 50
interacts with pressure Pg, not P2 (Br. 6). Appellant further argues that
pressure Pg is not measured at an output side of the metering valve 16, such
that “at no point does the valve 50 interact with a pressure prevailing at the
output side [i.e., P2] of the valve 16” (Br. 6, 7). Appellant contends that
Hofmann does not disclose “a pressure recording element recording pressure
changes at an output side of a metering device and with which a means for
regulating a pressure of a reducing agent interacts so that pressure changes
have an influence on the pressure regulation” (Br. 7).
The Examiner responds that Hofmann discloses “the pressure detected
at P2 is directly influenced by a change in the air pressure Pg” (Answer 9).
The Examiner further states that any drop in Pg also results in a drop in P2,
and to keep a pressure difference (P2-P1) across valve 16 constant, control
valve 50 is operated to increase a part of the urea recirculated through the
branched line 52 in order to obtain a correspondingly lower pressure P1
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Last modified: September 9, 2013