Ford Global Technolgoies, LLC

Caterpillar Inc.

Grant Alan Ingram

Gopichandra Surnilla

David Karl Bidner

Shane Elwart

Jeffrey Scott Hepburn

Christian Thomas Goralski, Jr

Joseph Robert Theis

John M Roth

Richard George Ingram

George T Chiu

Matthew A Franchek

Disclosed is a method for controlling a lean burn engine coupled to an emission control device that stores oxidants during lean operation, and reacts the stored oxidants during stoichiometric or rich operation, the method comprising estimating amounts of NOx stored in the device along a plurality of axial positions of the device and adjusting an operating parameter based on said estimate.

[object Object]

A method is disclosed for controlling operation of an engine coupled to an exhaust treatment catalyst. Under predetermined conditions, the method operates an engine with a first group of cylinders combusting a lean air/fuel mixture and a second group of cylinders pumping air only (i.e., without fuel injection). In addition, the engine control method also provides the following features in combination with the above-described split air/lean mode: idle speed control, sensor diagnostics, air/fuel ratio control, adaptive learning, fuel vapor purging, catalyst temperature estimation, default operation, and exhaust gas and emission control device temperature control. In addition, the engine control method also changes to combusting in all cylinders under preselected operating conditions such as fuel vapor purging, manifold vacuum control, and purging of stored oxidants in an emission control device.

Method and system for rapid heating of an emission control device

A more precise method for determining the oxygen storage capacity of an exhaust gas aftertreatment device is presented. The most accurate capacity estimate is obtained while the engine is idling or during low load operation. The capacity is determined by integrating the output of an oxygen sensor located downstream of the device during a period of time that it takes to store more than a predetermined amount of oxygen in the device. The overall LNT efficiency can then be inferred from its oxygen storage capacity. This method allows for improved emission control and fuel economy.

Oxygen storage capacity estimation

A method for determining the efficiency of a three-way catalyst is presented. It is shown that more accurate results are achieved if the efficiency estimates are performed when the engine is at idle or during low load operating conditions. The efficiency is inferred from the amount of fuel required to purge the device after it has been fully saturated with oxidants due to lean operation. Due to improved accuracy and reduced reductant waste, this method allows for improved emission control and fuel efficiency.

Oxidant storage capacity estimation

A more accurate method for determining a NOx storage efficiency of an exhaust gas aftertreatment device is presented. The method teaches determining NOx storage efficiency as a function of available LNT NOx storage capacity, which is calculated based on a ratio of an instantaneous value of an amount of NOx stored in the device and total device storage capacity at present operating conditions. Using this method prevents overfilling of the device and inefficient purging, thus improving emission control and fuel economy.

Nox trap efficiency

A method for estimating the amount of NO stored in a lean NO trap. The method includes determining a change in the oxygen concentration between an exhaust air/fuel ratio entering the lean NO trap and exiting the lean NO trap to determine the amount of NO absorbed in the trap and correcting such determination for water gas shift reaction effects in such change in oxygen concentration determination.

Lean NOx storage estimation based on oxygen concentration corrected for water gas shift reaction

A method for monitoring efficiency of an exhaust gas aftertreatment device is presented. The efficiency is inferred from the amount of fuel required to perform purge of the device after it has been saturated with exhaust gas components such as NOx and oxygen to a predetermined level. The level of saturation is determined from the amount of tailpipe emissions as indicated by the tailpipe exhaust gas sensor. This method improves precision in determining device efficiency and therefore eliminates unnecessary sulfur purges and improves fuel economy. Also, better emission control is achieved since the tailpipe exhaust gas sensor allows closed loop monitoring of NOx emissions and prevents the device from overfilling.

Exhaust gas aftertreatment device efficiency estimation

An improved method for monitoring an efficiency of a three-way catalyst coupled in an exhaust passage of an internal combustion engine is presented. First, a reference efficiency estimate (shortly after a SOx purge) is generated based on several data points obtained during normal vehicle driving conditions over varying device temperatures. Next, a current efficiency estimate is obtained from several data points. The two estimates are compared to obtain a measure of reduction in the catalyst efficiency due to device sulfation.

An engine air/fuel controller is responsive to an exhaust gas oxygen sensor positioned upstream of a catalytic converter and a proportional exhaust gas oxygen sensor positioned downstream of the catalytic converter. An air/fuel ratio signal provided by the downstream exhaust gas oxygen sensor is adjusted by a correction bias value. A first preferred method of deriving the correction bias value includes calculating the difference between the average of the upstream and downstream air/fuel ratios when the upstream sensor indicates lean operation of the engine. The second preferred method includes deriving the correction bias according a pre-determined and pre-programmed correction bias function, which provides correction bias values as a function of the of the air/fuel ratio measured by the downstream sensor.

Method for correcting an exhaust gas oxygen sensor

A method for improving a purge conversion efficiency of a Lean NOx Trap coupled downstream of a lean-burn internal combustion engine is presented. This method recognizes that during a purge of the LNT, its temperature increases due to the exothermic reactions in the LNT. Once the LNT temperature exceeds a certain threshold, further increases lead to a reduction in the NOx storage capacity, and therefore an increase in NOx emissions during the purge of the LNT. Therefore, it is proposed to cool the LNT temperature once the threshold is exceeded. This method improves emission control and fuel economy during purge.

NOx purge air/fuel ratio selection

A method for improving a purge conversion efficiency of a Lean NOx Trap coupled downstream of a lean-burn internal combustion engine is presented. This method proposes adjusting the purge air-fuel ratio of the device based on its temperature. According to the proposed method, a less rich air-fuel ratio is provided at lower operating temperatures to reduce hydrocarbon emissions since within this temperature range air-fuel ratio does not have a significant affect on NOx emissions. At mid-range operating temperatures, the air-fuel ratio is gradually decreased (made more rich) to reduce NOx emissions. And, finally, at high operating temperatures, HC and NOx emissions are reduced, and therefore, the purge air-fuel is kept at a constant more rich value. This method improves emission control and fuel economy during purge.

A power management controller for a machine which may be subjected to work assignments taxing the available power of the machine which automatically allocates power to the machine subsystems to ensure continued acceptable machine performance as power demands change.

Power management system and method

A method and apparatus for determining the capacity of a trap to store NO based on the change in oxygen storage in the trap occurring as a result of sulfation of the trap.

Growing community of inventors

West Lafayette, IN, United States of America

Grant Alan Ingram