Appeal No. 1998-2958
Application No. 08/671,516
The invention is directed to the determination of air/fuel ratio of an engine combustion process
from exhaust emissions.
Representative independent claim 1 is reproduced as follows:
1. A computer-implemented method for determining air/fuel ratio of an engine's combustion
process from its exhaust emissions, the method comprising the steps of:
taking a sample of the exhaust emissions from an operating engine to obtain exhaust gases and
water;
measuring concentration of the exhaust gases in the sample, and providing corresponding
exhaust gas concentration data;
selecting a calculation type from a predetermined set of calculation types stored in a computer
system, including a computer;
calculating with the computer an amount of water produced in the combustion process based
on the selected calculation type and the exhaust concentration data;
calculating with the computer an amount of oxygen used in the combustion process based on
the amount of water produced in the combustion process and the exhaust gas concentration data;
calculating with the computer the air/fuel ratio based on the calculated amount of oxygen; and
displaying the air/fuel ratio on a display coupled to the computer.
The examiner relies on the following reference:
Yamamoto et al. (Yamamoto) 4,751,907 Jun. 21, 1988
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