System and method for controlling exhaust stream temperature

A method of controlling an exhaust stream temperature at a point along an exhaust system including an oxidation catalyst, a particulate filter including an outlet, and a fuel injector for injecting fuel into an exhaust stream at a location upstream from the outlet of the particulate filter, the method comprising the steps of:

• providing an adaptive control model that models a portion of the exhaust system;
• monitoring the exhaust stream temperature at the point along the exhaust system;
• determining a target temperature for the point along the exhaust system;
• calculating a difference between the target temperature for the point along the exhaust system and the exhaust stream temperature at the point along the exhaust system;
• providing a controller including a proportion gain and an integral gain;
• processing, by the controller, the calculated difference between the target temperature for the point along the exhaust system and the exhaust stream temperature at the point along the exhaust system, to determine a time derivative of the exhaust stream temperature at the point along the exhaust system;
• providing the time derivative to the adaptive control model, wherein the time derivative is a parameter of the adaptive control model;
• determining an expected temperature for the point along the exhaust system based on the adaptive control model;
• calculating a difference between the exhaust stream temperature at the point along the exhaust system and the expected temperature for the point along the exhaust system;
• determining an error in the adaptive control model based on the difference between the exhaust stream temperature at the point along the exhaust system and the expected temperature for the point along the exhaust system;
• changing the adaptive control model to reduce the error;
• calculating a fuel injection flow rate at which fuel is injected into the exhaust stream by the fuel injector, based on the adaptive control model;
• and
• controlling an operation of the fuel injector based on the calculated fuel injection flow rate, to control the exhaust stream temperature at the point along the exhaust system.

A method of controlling an exhaust stream temperature at a point along an exhaust system including a catalytic converter, a diesel particulate filter operationally connected to the catalytic converter and located downstream from the catalytic converter, and a fuel injector for injecting fuel into an exhaust stream at a location upstream from the catalytic converter, the method comprising the steps of:

• providing an adaptive control model that models a portion of the exhaust system, the portion including the catalytic converter;
• monitoring the exhaust stream temperature at the point along the exhaust system, wherein the point along the exhaust system is located between the catalytic converter and the diesel particulate filter;
• determining a target temperature for the point along the exhaust system;
• calculating a difference between the target temperature for the point along the exhaust system and the exhaust stream temperature at the point along the exhaust system;
• providing a controller including a proportion gain and an integral gain;
• processing, by the controller, the calculated difference between the target temperature for the point along the exhaust system and the exhaust stream temperature at the point along the exhaust system, to determine a time derivative of the exhaust stream temperature at the point along the exhaust system;
• providing the time derivative to the adaptive control model, wherein the time derivative is a parameter of the adaptive control model;
• determining an expected temperature for the point along the exhaust system based on the adaptive control model;
• calculating a difference between the exhaust stream temperature at the point along the exhaust system and the expected temperature for the point along the exhaust system;
• determining an error in the adaptive control model based on the difference between the exhaust stream temperature at the point along the exhaust system and the expected temperature for the point along the exhaust system;
• changing the adaptive control model to reduce the error;
• monitoring a plurality of catalytic converter inlet conditions including oxygen concentration in the exhaust stream, mass flow rate of the exhaust stream, and temperature of the exhaust stream;
• determining another parameter of the adaptive control model based on at least one of the plurality of catalytic converter inlet conditions;
• calculating a fuel injection flow rate at which fuel is injected into the exhaust stream by the fuel injector, based on the adaptive control model;
• and
• controlling an operation of the fuel injector based on the calculated fuel injection flow rate, to control the exhaust stream temperature at the point along the exhaust system.

A regeneration control system for an engine exhaust system, comprising:

• an oxidation catalyst;
• a particulate filter including an outlet;
• a fuel injector for injecting fuel into an exhaust stream at a location upstream from the outlet of the particulate filter, wherein the exhaust stream flows through the particulate filter;
• and
• a processor for controlling an operation of the fuel injector based on an adaptive control model that adaptively models a portion of the exhaust system, wherein the processor is programmed to:
• calculate a desired fuel injection flow rate based on the adaptive control model,
• control the operation of the fuel injector to control an exhaust stream temperature at a point along the exhaust system,
• determine an expected temperature,
• calculate a difference between a temperature of the exhaust stream and the expected temperature,
• determine an error in the adaptive control model based on the difference between the temperature of the exhaust stream and the expected temperature, and
• change the adaptive control model to reduce the error;
• and
• a first temperature sensor for sensing a temperature at the point along the exhaust system, wherein the processor is further programmed to:
• calculate a difference between the temperature at the point along the exhaust system and a target temperature for the point along the exhaust system, and
• process the calculated difference between the temperature at the point along the exhaust system and the target temperature for the point along the exhaust system using a control algorithm including a proportional gain setting and an integral gain setting, to determine a time derivative of the exhaust stream temperature at the point along the exhaust system,
• wherein the time derivative of the exhaust stream temperature at the point along the exhaust system is a parameter of the adaptive control model.

A regeneration control system for an engine exhaust system, comprising:

• a particulate filter including an outlet;
• an oxidation catalyst provided in a catalytic converter that is located upstream from the particulate filter;
• a fuel injector for injecting fuel into an exhaust stream at a location upstream from the outlet of the particulate filter, wherein the exhaust stream flows through the particulate filter;
• a first temperature sensor for sensing an exhaust stream temperature at a point along the exhaust system;
• and
• a processor for controlling an operation of the fuel injector based on an adaptive control model that adaptively models a portion of the exhaust system including the catalytic converter, wherein the processor is programmed to:
• calculate a difference between the exhaust stream temperature at the point along the exhaust system and a target temperature for the point along the exhaust system,
• process the calculated difference between the exhaust stream temperature at the point along the exhaust system and the target temperature for the point along the exhaust system using a control algorithm including a proportional gain setting and an integral gain setting, to determine a time derivative of the exhaust stream temperature at the point along the exhaust system, wherein the time derivative of the exhaust stream temperature at the point along the exhaust system is a parameter of the adaptive control model,
• determine an expected temperature for the point along the exhaust system,
• calculate a difference between the exhaust stream temperature at the point along the exhaust system and the expected temperature for the point along the exhaust system,
• determine an error in the adaptive control model based on the difference between the exhaust stream temperature at the point along the exhaust system and the expected temperature for the point along the exhaust system,
• change the adaptive control model to reduce the error,
• calculate a fuel injection flow rate based on the adaptive control model, and
• control the operation of the fuel injector to control the exhaust stream temperature at the point along the exhaust system.