Patent ID: 7155331

Claim:
A method for estimation of a NOx mass flow rate in a diesel engine exhaust stream, the method comprising: (a) using a mathematical function to estimate the NOx mass flow rate, the mathematical function being one of: (i) Y=K 1 X 1 +K 2 , where Y is the estimated NOx mass flow level in mmol/second, X 1 is the engine output in horsepower, K 1 is a first constant, and K 2 is a second constant; (ii) Y=K 3 X 2 +K 4 , where Y is the estimated NOx mass flow level in mmol/second, X 2 is the engine intake pressure in PSI, K 3 is a third constant, and K 4 is a fourth constant; (iii) Y=K 5 e K6X3 , where Y is the estimated NOx mass flow level in mmol/second, X 3 is the engine's turbo-outlet temperature in degrees Celsius, K 5 is a fifth constant, and K 6 is a sixth constant; and (iv) Y=K 7 e K8X4 , where Y is the estimated NOx mass flow level in mmol/second, X 4 is the percentage of oxygen in the engine's outlet exhaust stream, K 7 is a seventh constant, and K 8 is an eighth constant.