Protecting an oxidation catalyst upstream of a particulate filter for a diesel engine by limitation of injected fuel

Abstract

A method for controlling an engine including an oxidation catalytic converter. The method, if certain criteria are verified, calculates a maximum amount of fuel to be post-injected based on a measured air flow rate and a threshold operating temperature of the oxidation catalytic converter.

1 - 8 . (canceled) 
   
   
       9 . A method for controlling an engine including an oxidation catalytic converter, comprising:
 if at least one pre-defined criterion is satisfied, calculating a maximum quantity of fuel to be post-injected based on a measured air flow rate and a limit operating temperature of the oxidation catalytic converter.   
   
   
       10 . The method as claimed in  claim 9 , further comprising measuring the air flow rate in an exhaust line. 
   
   
       11 . The method as claimed in  claim 9 , wherein the criterion is that the measured air flow rate is lower than an air flow rate setpoint. 
   
   
       12 . The method as claimed in  claim 9 , further comprising:
 measuring an exhaust gas temperature in an exhaust line;   ordering an increase in a quantity of fuel post-injected into the exhaust line if the measured exhaust temperature is lower than a temperature setpoint; and   ordering a decrease in the quantity of fuel post-injected into the exhaust line if the measured exhaust gas temperature is higher than the temperature setpoint.   
   
   
       13 . An engine comprising:
 an oxidation catalytic converter; and   a computer that calculates a maximum quantity of fuel to be post-injected based on a measured air flow rate and a limit operating temperature of the oxidation catalytic converter.   
   
   
       14 . The engine as claimed in  claim 13 , further comprising a flowmeter that measures air flow rate in the exhaust line. 
   
   
       15 . The engine as claimed in  claim 13 , further comprising a temperature probe that measures exhaust gas temperature in the exhaust line, and wherein the computer is further configured to order an increase or decrease, respectively, in a quantity of fuel post-injected into the exhaust line if the measured exhaust temperature is lower or higher, respectively, than a temperature setpoint. 
   
   
       16 . A motor vehicle, comprising an engine as claimed in  claim 13 .