Smart def injector for low temperature reductant delivery

Abstract

A DEF injector is connected to the exhaust system of a vehicle upstream of an SCR catalyst, and is further connected to the ECU or DCU. An exhaust temperature sensor and an exhaust mass flow rate sensor are connected to the ECU or DCU, and further connected to the DEF injector. The ECU or DCU controls the DEF injector based on exhaust temperature and exhaust mass flow rate when the exhaust temperature is above a certain threshold. The DEF injector itself, or a dedicated DEF injector controller, overrides and/or supplements the control logic located within the ECU or DCU to control the DEF injector to inject DEF at reduced rates when the exhaust temperature and/or the exhaust mass flow rate are lower than the threshold for DEF injection set by the ECU or DCU.

What is claimed is: 
     
         1 . A vehicle having a Smart DEF Injector for Low Temperature Reductant Delivery, comprising:
 an engine;   an Engine Control Unit (ECU) or Diesel Control Unit (DCU) connected to the engine and configured to control the engine;   an exhaust system connected to the engine;   an SCR catalyst connected to the exhaust system;   a Diesel Exhaust Fluid (DEF) injector connected to the exhaust system upstream of the SCR catalyst, and further connected to the ECU or DCU;   an exhaust temperature sensor connected to the ECU or DCU, and further connected to the DEF injector;   an exhaust mass flow rate sensor connected to the ECU or DCU, and further connected to the DEF injector; wherein:   the ECU or DCU is further configured with control logic for controlling the DEF injector based on exhaust temperature information provided by the exhaust temperature sensor and exhaust mass flow rate information provided by the exhaust mass flow rate sensor;   the DEF injector is configured with control logic and is configured to override and/or supplement the control logic located within the ECU or DCU;   the control logic of the DEF injector uses exhaust temperature information provided by the exhaust temperature sensor and exhaust mass flow rate information provided by the exhaust mass flow rate sensor to control the DEF injector to inject DEF at reduced rates when the exhaust temperature and/or the exhaust mass flow rate are lower than a threshold for DEF injection set by the ECU or DCU.   
     
     
         2 . The vehicle of  claim 1 , further comprising:
 a dedicated DEF injector controller connected to the DEF injector, wherein:   the exhaust temperature sensor is further connected to the DEF injector by way of the dedicated DEF injector controller;   the exhaust mass flow rate sensor is further connected to the DEF injector by way of the dedicated DEF injector controller; and   the control logic of the DEF injector resides within the dedicated DEF injector controller.   
     
     
         3 . The vehicle of  claim 2 , wherein:
 the dedicated DEF injector controller is further connected to the ECU or DCU.   
     
     
         4 . The vehicle of  claim 1 , wherein:
 the control logic of the DEF injector controls the DEF injector to inject DEF at reduced rates determined by setting an Excess Energy Ratio (EER) to a threshold value and solving for a mass flow rate of DEF.   
     
     
         5 . The vehicle of  claim 4 , wherein:
 the mass flow rate of DEF being determined as a percentage of fuel mass flow rate.   
     
     
         6 . The vehicle of  claim 1 , wherein:
 the DEF injector is a standard type DEF injector; and   the threshold for DEF injection set by the ECU or DCU is 190 degrees Celsius.   
     
     
         7 . The vehicle of  claim 1 , wherein:
 the DEF injector is a flash-boil type DEF injector; and   the threshold for DEF injection set by the ECU or DCU is 150 degrees Celsius.   
     
     
         8 . A Smart DEF Injection Arrangement for Low Temperature Reductant Delivery for a vehicle having an engine, an Engine Control Unit (ECU) or Diesel Control Unit (DCU) connected to the engine and configured to control the engine, an exhaust system connected to the engine, and an SCR catalyst connected to the exhaust system, comprising:
 a Diesel Exhaust Fluid (DEF) injector connected to the exhaust system upstream of the SCR catalyst, and further connected to the ECU or DCU;   an exhaust temperature sensor connected to the ECU or DCU, and further connected to the DEF injector;   an exhaust mass flow rate sensor connected to the ECU or DCU, and further connected to the DEF injector; wherein:   the ECU or DCU is further configured with control logic for controlling the DEF injector based on exhaust temperature information provided by the exhaust temperature sensor and exhaust mass flow rate information provided by the exhaust mass flow rate sensor;   the DEF injector is configured with control logic and is configured to override and/or supplement the control logic located within the ECU or DCU;   the control logic of the DEF injector uses exhaust temperature information provided by the exhaust temperature sensor and exhaust mass flow rate information provided by the exhaust mass flow rate sensor to control the DEF injector to inject DEF at reduced rates when the exhaust temperature and/or the exhaust mass flow rate are lower than a threshold for DEF injection set by the ECU or DCU.   
     
     
         9 . The arrangement of  claim 8 , further comprising:
 a dedicated DEF injector controller connected to the DEF injector, wherein:   the exhaust temperature sensor is further connected to the DEF injector by way of the dedicated DEF injector controller;   the exhaust mass flow rate sensor is further connected to the DEF injector by way of the dedicated DEF injector controller; and   the control logic of the DEF injector resides within the dedicated DEF injector controller.   
     
     
         10 . The arrangement of  claim 9 , wherein:
 the dedicated DEF injector controller is further connected to the ECU or DCU.   
     
     
         11 . The arrangement of  claim 8 , wherein:
 the control logic of the DEF injector controls the DEF injector to inject DEF at reduced rates determined by setting an Excess Energy Ratio (EER) to a threshold value and solving for a mass flow rate of DEF.   
     
     
         12 . The arrangement of  claim 11 , wherein:
 the mass flow rate of DEF being determined as a percentage of fuel mass flow rate.   
     
     
         13 . The arrangement of  claim 8 , wherein:
 the DEF injector is a standard type DEF injector; and   the threshold for DEF injection set by the ECU or DCU is 190 degrees Celsius.   
     
     
         14 . The arrangement of  claim 8 , wherein:
 the DEF injector is a flash-boil type DEF injector; and   the threshold for DEF injection set by the ECU or DCU is 150 degrees Celsius.   
     
     
         15 . A method of reducing vehicle emissions in a vehicle having an engine, comprising the steps of:
 connecting an Engine Control Unit (ECU) or Diesel Control Unit (DCU) to the engine and configuring the ECU or DCU to control the engine;   connecting an exhaust system to the engine;   connecting an SCR catalyst to the exhaust system;   connecting a Diesel Exhaust Fluid (DEF) injector to the exhaust system upstream of the SCR catalyst, and further connecting the DEF injector to the ECU or DCU;   connecting an exhaust temperature sensor to the ECU or DCU, and to the DEF injector;   connecting an exhaust mass flow rate sensor to the ECU or DCU, and to the DEF injector;   configuring the ECU or DCU with control logic for controlling the DEF injector based on exhaust temperature information provided by the exhaust temperature sensor and exhaust mass flow rate information provided by the exhaust mass flow rate sensor;   configuring the DEF injector with control logic for overriding and/or supplementing the control logic configured within the ECU or DCU;   controlling the DEF injector to inject DEF at reduced rates when the exhaust temperature and/or the exhaust mass flow rate are lower than a threshold for DEF injection set by the ECU or DCU, using the control logic of the DEF injector, exhaust temperature information provided by the exhaust temperature sensor, and exhaust mass flow rate information provided by the exhaust mass flow rate sensor   
     
     
         16 . The method of  claim 15 , further comprising the steps of:
 connecting a dedicated DEF injector controller to the DEF injector;   further connecting the exhaust temperature sensor to the DEF injector by way of the dedicated DEF injector controller;   further connecting the exhaust mass flow rate sensor to the DEF injector by way of the dedicated DEF injector controller; and   configuring the control logic of the DEF injector within the dedicated DEF injector controller.   
     
     
         17 . The method of  claim 16 , further comprising the steps of:
 further connecting the dedicated DEF injector controller to the ECU or DCU.   
     
     
         18 . The method of  claim 15 , further comprising the steps of:
 controlling the DEF injector to inject DEF at reduced rates determined by setting an Excess Energy Ratio (EER) to a threshold value and solving for a mass flow rate of DEF using the control logic of the DEF injector.   
     
     
         19 . The method of  claim 15 , wherein:
 the DEF injector is a standard type DEF injector; and   the threshold for DEF injection set by the ECU or DCU is 190 degrees Celsius.   
     
     
         20 . The method of  claim 15 , wherein:
 the DEF injector is a flash-boil type DEF injector; and   the threshold for DEF injection set by the ECU or DCU is 150 degrees Celsius.