Timer-based warning structure for detecting and indicating an overloaded diesel particulate filter

Abstract

An engine ( 12 ) has an exhaust system ( 16 ) containing a diesel particulate filter (DPF 20 ) and timer-based warning structure ( 30 ) for detecting and indicating particulate overloading of the DPF as the engine runs.

1 . An engine comprising:
 an exhaust system containing a diesel particulate filter (DPF);   and timer-based warning structure for detecting and indicating particulate overloading of the DPF as the engine runs, the warning structure comprising,   a) a source for providing data representing current particulate loading of the DPF,   b) processing apparatus for i) repeatedly processing the current particulate loading data and data defining a threshold level of particulate loading at which a request for regeneration of the DPF should be issued, and ii) when a result of that processing discloses that the current particulate loading is at least as great as the threshold level, enabling an indicator, and iii) when processing of the current particulate loading data and data defining a hierarchy of zones of successively greater particulate overloading of the DPF greater than the threshold level discloses that the current particulate loading has remained in one of those zones for a length of time set by a timer, causing the enabled indicator to give an indication that the DPF has become overloaded.   
   
   
       2 . An engine as set forth in  claim 1  wherein the data defining a hierarchy of zones defines first, second, and third zones of successively greater particulate overloading in that order, and the first zone has a lower limit equal to the threshold level. 
   
   
       3 . An engine as set forth in  claim 2  wherein when processing of the current particulate loading data and data defining the hierarchy of zones discloses that current particulate loading has remained in the second zone for a length of time set by a timer, the processing apparatus issues an engine de-rate request to an engine control strategy for de-rating the engine. 
   
   
       4 . An engine as set forth in  claim 3  wherein when processing of the current particulate loading data and data defining the hierarchy of zones discloses that current particulate loading has remained in the third zone for a length of time set by a timer, the processing apparatus issues an engine de-rate request that is more extreme than the de-rate request issued in consequence of particulate loading remaining in the second zone. 
   
   
       5 . An engine comprising:
 an exhaust system containing a diesel particulate filter (DPF);   and timer-based warning structure for detecting and indicating particulate overloading of the DPF as the engine runs, the warning structure comprising,   a) a source for providing data representing current particulate loading of the DPF,   b) processing apparatus for repeatedly processing the current particulate loading data and data defining a hierarchy of zones of successively greater particulate overloading of the DPF, wherein each zone comprises a range bounded by a respective lower level of particulate loading and a respective upper level of particulate loading, and   c) the processing apparatus comprises, for each zone, an input stage for determining if the current particulate loading is greater than some level of loading, a timer that runs concurrently with the input stage disclosing that current particulate loading is greater than that level, and an output stage that issues a signal to indicate when the respective timer has disclosed that particulate loading has remained greater than that level for some set length of time.   
   
   
       6 . An engine as set forth in  claim 5  wherein each input stage comprises two comparison functions and an AND logic function that processes outputs of the AND logic function. 
   
   
       7 . An engine as set forth in  claim 5  wherein each output stage comprises a comparison function to which the timer is one input and to which a parameter for setting the respective length of time that the respective timer must run in order for the output stage to issue the respective signal is another input. 
   
   
       8 . An engine as set forth in  claim 5  further including one or more indicators that are operated by signals from one or more output stages. 
   
   
       9 . An engine as set forth in  claim 8  wherein the one or more indicators comprise lamps that disposed for viewing by an operator of a motor vehicle containing the engine. 
   
   
       10 . An engine as set forth in  claim 5  further including an engine control system, and wherein respective signals from certain output stages cause the control system to de-rate the engine to respective de-rate levels.