Southwest Research Institute

Yiqun Huang

Shizuo Sasaki

Magdi K Khair

Rijing Zhan

Qilong Lu

Cynthia Chaffin Webb

Joseph Grogan

Gary Dale Neely

Christopher Alan Sharp

Jeffrey A Leet

An adaptive method is used for LNT desulfation and regeneration. The desulfation method involves adapting the amount of sulfur loading to trigger a desulfation event in accordance with the current adsorption capacity of the LNT. The method involves monitoring the current sulfur loading and the current LNT adsorption capacity. This data is used to calculate a loading amount 'trigger', whose value varies over the LNT lifetime. Whenever this trigger amount is reached, a desulfation event is performed. The regeneration method is similar, with the baseline data and loading threshold being determined by NOx loading rather than sulfur loading.

Adaptive desulfation and regeneration methods for lean NOx trap

The present disclosure relates to a method or apparatus for controlling reductant dosing level introduced to a selective catalytic reduction device. The method or apparatus may determine available reductant and determine a distance to a source of reductant. This may be followed by adjusting a reductant dosing level based upon the available reductant and the distance to the reductant source. The apparatus may be installed in a vehicle and may also regulate in-cylinder emission control variables to reduce NOx emissions.

Adaptive reductant dosing and emission control strategies

A method and apparatus for regenerating exhaust treatment devices. Incomplete combustion products may be selectively provided in at least one cylinder of multi-cylinder internal combustion engine. This may then be followed by directing the products to an engine exhaust treatment device. The temperature of the engine exhaust treatment device may then be increased due to exposure to the products of incomplete combustion. The catalyst in the converter may then be regenerated due to the temperature increase.

Apparatus and method for regenerating exhaust treatment devices

A diesel engine exhaust treatment system has both a NOx reduction device and a diesel particulate filter. The system is designed to ensure that the NOx reduction device operates within its optimal temperature conditions. Using exhaust flow control valves, the exhaust flow can be directed into either the NOx reduction device first or into the diesel particulate filter first, and then into the other device, before exiting out the tailpipe.

Exhaust after-treatment system with flow control for optimum temperature conditions

A reconfigurable exhaust system provides selective positioning of exhaust gas treatment devices either near, or spaced from, the exhaust gas outlet port of a turbine of a turbocharged Diesel engine. In some embodiments, auxiliary air or a heat exchanger are arranged to cool the exhaust gas when required.

Method for controlling exhaust gas flow and temperature through regenerable exhaust gas treatment devices

A method and system for controlling exhaust gas temperature at a diesel particulate filter during regeneration. The temperature rise is controlled at a rate that will prevent harm to the filter caused by high temperatures and rapid increases.

Regeneration control for diesel particulate filter for treating diesel engine exhaust

Uncontrolled regeneration in a Diesel particulate filter is prevented by controlling the concentration and mass flowrate of oxygen passing through the Diesel particulate filter during regeneration.

Method for controlling temperature in a diesel particulate filter during regeneration

Exhaust system and method for controlling exhaust gas flow and temperature through regenerable exhaust gas treatment devices

A method for rapidly transitioning from a lean combustion mode to a rich combustion mode, such as often required for the regeneration of aftertreatment devices, is provided by abrupt intake air reduction and a concurrent abrupt increase in fuel injection quantity with accompanying retardation of fuel injection timing. The abrupt increase in fuel quantity is to a maximum value sufficient to immediately provide a defined initial rich air/fuel ratio for a coexistent oxygen concentration in the cylinder. The fuel quantity is then proportionally reduced from the maximum value to a target fuel quantity to maintain a target air/fuel ratio during the transition. Simultaneously, injection timing is abruptly retarded to a value sufficient to avoid torque increase as a result of the increased injected fuel. The injection timing is subsequently proportionally advanced from the abruptly retarded timing value when the target fuel quantity and air/fuel ratio values are achieved.

Method for rapid, stable torque transition between lean rich combustion modes

High exhaust gas temperatures whereby sulfur is removed from a lean NOx traps simultaneously with regeneration of a Diesel particulate filter is provided by alternating engine operation in respectively defined lean and rich combustion modes. The duration and frequency of the respective lean and rich operating modes, as well as the air/fuel ratio during the respective modes, are preferably controlled by the sensed temperature of the lean NOx trap substrate.

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A method and system for controlling the temperature of recirculated exhaust gas in an exhaust gas recirculation (EGR) system, such as those used in connection with diesel engines. An EGR loop (which may be either a high pressure loop or a low pressure loop) has a dual-leg segment with an EGR cooler on one leg and an EGR heater on the other leg. By means of a valve, the EGR gas may be diverted to either one leg or the other, thereby providing either cooled or heated EGR gas to the engine.

Exhaust gas recirculation system with control of EGR gas temperature

An in-cylinder ion sensor provides a signal representative of the air/fuel ratio of the charge mixture as an engine starts. The signal representative of the air/fuel ratio is used as a feedback signal for an electronic control unit to perform cold-start closed-loop control during an initial operating period from a cold-start before an on-board oxygen sensor is able to warm up. After reaching a functional operating temperature, the oxygen sensor provides a signal that is used as an adaptive calibration tool which allows the electronic control unit to calibrate the ion sensor signal and use that signal for controlling the air/fuel ratio during cold start operation.

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San Antonio, TX, United States of America

Yiqun Huang