US 9,810,672 B2
Method of operating an engine
Amiyo K. Basu, Peoria, IL (US)
Assigned to Caterpillar Inc., Peoria, IL (US)
Filed by Caterpillar Inc., Peoria, IL (US)
Filed on Dec. 4, 2014, as Appl. No. 14/559,978.
Prior Publication US 2016/0160785 A1, Jun. 9, 2016
Int. Cl. F02D 41/00 (2006.01); G01N 33/00 (2006.01); F01N 3/20 (2006.01); F01N 3/10 (2006.01); F02D 41/14 (2006.01)
CPC G01N 33/0037 (2013.01) [F01N 3/208 (2013.01); F02D 41/1462 (2013.01); F01N 3/106 (2013.01); F01N 3/2066 (2013.01); F01N 2430/00 (2013.01); F01N 2560/026 (2013.01); F01N 2560/06 (2013.01); F01N 2560/08 (2013.01); F01N 2560/14 (2013.01); F01N 2610/02 (2013.01); F01N 2900/0412 (2013.01); F01N 2900/0601 (2013.01); F01N 2900/08 (2013.01); F01N 2900/1402 (2013.01); F02D 41/1446 (2013.01); F02D 41/1448 (2013.01); F02D 2200/0414 (2013.01); F02D 2200/0418 (2013.01); F02D 2200/1004 (2013.01); F02D 2200/703 (2013.01); F02D 2250/36 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method of operating an engine, the method comprising:
determining, by a controller, a temperature and a pressure of intake air;
determining, by the controller, a temperature and a pressure of exhaust generated by the engine;
determining, by the controller, a work performed by the engine based at least on an engine speed of the engine;
determining, by the controller, heating losses of the engine;
determining, by the controller, an enthalpy of the intake air based at least on the work performed by the engine, the heating losses of the engine, a heating value of a fuel used for combustion within the engine, and the temperature and the pressure of the exhaust;
determining, by the controller, a humidity value of the intake air based on the enthalpy and the temperature and the pressure of the intake air;
determining, by the controller, an amount of nitrogen oxides (NOx) as a function of the humidity value of the intake air; and
controlling, by the controller, an operation of the engine based on the amount of NOx,
controlling the operation of the engine based on the amount of NOx including controlling, based on the amount of NOx, one or more of:
an Exhaust Gas Recirculation (EGR) flow rate for the engine,
a temperature of a coolant utilized by the engine,
an ignition timing of the engine,
a flow rate of the fuel,
a flow rate of the intake air, or
a fuel injection pressure.