Regeneration assist transition period

Abstract

A power system comprising an engine that produces exhaust, a particulate filter that traps soot from the engine, and a controller that switches the power system from a first operation mode into a second operation mode to regenerate the particulate filter wherein a transition between the first operation mode and the second operation mode occurs at a slower rate when an amount of soot in the particulate filter changes relative to a threshold than when a load on the engine changes.

1 . A power system comprising:
 an engine that produces exhaust;   a particulate filter that traps soot from the engine; and   a controller that switches the power system from a first operation mode into a second operation mode to regenerate the particulate filter wherein a transition between the first operation mode and the second operation mode occurs at a slower rate when an amount of soot in the particulate filter changes relative to a threshold than when a load on the engine changes.   
     
     
         2 . The power system of  claim 1  wherein the second operation mode includes an actuating of a regeneration valve and the regeneration valve actuates at the slower rate when the amount of soot in the particulate filter changes relative to the threshold than when the load on the engine increases. 
     
     
         3 . The power system of  claim 1  wherein a transition from the second operation mode back to the first operation mode occurs at the slower rate when the amount of soot in the particulate filter falls below the threshold than when the load on the engine increases. 
     
     
         4 . The power system of  claim 3  wherein the second operation mode includes a closing of a regeneration valve and the regeneration valve opens at the slower rate when the amount of soot in the particulate filter falls below the threshold than when the load on the engine increases. 
     
     
         5 . The power system of  claim 4  wherein the regeneration valve is a backpressure valve disposed in an exhaust conduit routing the exhaust. 
     
     
         6 . The power system of  claim 5  wherein the backpressure valve opens in greater than one second when the amount of soot in the particulate filter falls below the threshold and the backpressure valve opens in less than one second when the load on the engine increases. 
     
     
         7 . The power system of  claim 5  wherein the backpressure valve opens in greater than two seconds when the amount of soot in the particulate filter falls below the threshold and the backpressure valve opens in less than one second when the load on the engine increases. 
     
     
         8 . A power system comprising:
 an engine that produces exhaust;   an exhaust conduit routing the exhaust;   a backpressure valve disposed in the exhaust conduit; and   a controller that actuates the backpressure valve at a first rate under a first condition and actuates the backpressure valve at a second rate faster than the first rate under a second condition.   
     
     
         9 . The power system of  claim 8  wherein the backpressure valve actuates at the first rate after the backpressure valve is no longer needed and actuates at the second rate when the backpressure valve would inhibit a power demand on the engine. 
     
     
         10 . The power system of  claim 9  further including a particulate filter that traps soot in the exhaust and the backpressure valve is used to regenerate the particulate filter. 
     
     
         11 . The power system of  claim 10  wherein the backpressure valve is no longer needed once the particulate filter no longer needs regeneration. 
     
     
         12 . The power system of  claim 11  wherein the backpressure valve partially closes to regenerate the particulate filter and opens at either the first or second rate. 
     
     
         13 . The power system of  claim 11  wherein the backpressure valve opens at the first rate when an amount of soot in the particulate filter falls below a threshold and the backpressure valve opens at the second rate when a load on the engine increases. 
     
     
         14 . The power system of  claim 8  wherein the backpressure valve actuates in greater than one second at the first rate the backpressure valve actuates in less than one second at the second rate. 
     
     
         15 . A method of controlling a power system comprising:
 operating the power system in a first operation mode;   operating the power system in a second operation mode to assist regeneration of a particulate filter;   transitioning the power system from the second operation mode to the first operation mode over a first period of time in response to an amount of soot in the particulate filter falling below a threshold; and   transitioning the power system from the second operation mode to the first operation mode over a second period of time less than the first period of time in response to a load on the power system increasing more than a threshold amount.   
     
     
         16 . The method of  claim 15  wherein the second operation mode includes actuating a regeneration valve and the regeneration valve actuates over a period of time greater than one second in response to the amount of soot in the particulate filter falling below a threshold and actuating the regeneration valve over a period of time less than one second in response to a load on the power system increasing more than a threshold amount. 
     
     
         17 . The method of  claim 15  wherein the second operation mode includes closing a regeneration valve and the regeneration valve opens over a period of time greater than one second in response to the amount of soot in the particulate filter falling below a threshold and opens over a period of time less than one second in response to a load on the power system increasing more than a threshold amount. 
     
     
         18 . The method of  claim 17  wherein the regeneration valve is a backpressure valve disposed in an exhaust conduit. 
     
     
         19 . The method of  claim 18  wherein the backpressure valve opens over a period of time greater than one second in response to the amount of soot in the particulate filter falling below a threshold and opens over a period of time less than one second in response to the load on the power system increasing more than a threshold amount. 
     
     
         20 . The method of  claim 15  wherein the power system operates under the second operation mode after an amount of soot in the particulate filter is above a threshold and the load on the power system is below a threshold amount for a current engine speed.