Patent ID: 11946400
Assignee: PACCAR INC
Field: Environmental technology (Chemistry)
Classification: CPC F  Y | IPC F

Claim 5:
6. A method for monitoring an oxidation catalyst that is arranged upstream of an SCR catalyst in an exhaust gas feedstream of a compression-ignition internal combustion engine, the method comprising:
determining, via a first temperature sensor, an inlet temperature upstream of the oxidation catalyst and determining, via a second temperature sensor, an in-use outlet temperature downstream of the oxidation catalyst;
determining, via a controller, an expected outlet temperature from the oxidation catalyst based upon the inlet temperature;
determining a fueling rate and a mass flowrate of the exhaust gas feedstream;
determining a temperature differential through the oxidation catalyst based upon the fueling rate and the mass flowrate of the exhaust gas feedstream;
determining the expected outlet temperature from the oxidation catalyst based upon the inlet temperature, the fueling rate, and the mass flowrate;
detecting a fault related to the oxidation catalyst based upon the expected outlet temperature from the oxidation catalyst and the in-use outlet temperature downstream of the oxidation catalyst; and
reporting, via the controller, the fault to at least one of a vehicle operator and a vehicle service center when the fault has occurred,
wherein determining the temperature differential through the oxidation catalyst is based upon the following relationship:, Δ
   ⁢
   
    T
    
     e
     ⁢
     x
     ⁢
     h
    
   
  
  =
  
   (
   
    
     
      
       m
       ˙
      
      
       H
       ⁢
       C
      
     
     *
     L
     ⁢
     H
     ⁢
     
      V
      
       H
       ⁢
       C
      
     
    
    
     C
     ⁢
     
      p
      
       e
       ⁢
       x
       ⁢
       h
      
     
     *
     
      
       m
       ˙
      
      
       e
       ⁢
       x
       ⁢
       h
      
     
    
   
   )
  
 

 wherein:
ΔTexh represents the temperature differential,
{dot over (m)}HC represents a mass flow rate of HC that is determined based upon the fueling rate,
LHVHC represents a lower heating value of fuel,
Cpexh represents a specific heat of the exhaust gas feedstream at a constant pressure, and
{dot over (m)}exh represents the mass flowrate of the exhaust gas feedstream, and
wherein determining the expected outlet temperature from the oxidation catalyst is based upon the temperature differential and the inlet temperature upstream of the oxidation catalyst.