Abstract: The invention refers to a method and apparatus for converting NOx and comprises the step of controlling a temperature in a NOx-LNT by adsorbing NOx in the LNT at a temperature below a predetermined temperature value to a predetermined value being the maximum amount of NOx to be stored at the predetermined temperature value, thereafter heating the LNT to the predetermined temperature value, and thereafter starting a regeneration process by addition of reducing agents.

Abstract: The invention relates to an internal combustion engine that can be operated in compression ignition mode, the engine comprising a fuel injector for each cylinder; a fuel injection controller for controlling fuel injection quantity and a piston in each cylinder whose compression action causes a mixture of air and fuel to be ignited. The engine is further provided with inlet and outlet valves and sensors for measuring various engine operating parameters. During compression ignition mode, the control unit controls the fuel injector to perform a first fuel injection before top dead center of the exhaust stroke during a period of negative valve overlap, and a second fuel injection during the piston compression stroke. The control unit may perform a switch between a first fuel injection strategy and at least one further fuel injection strategy in response to a change in load demand on the engine.

Abstract: A method for detecting a malfunction in a manifold absolute pressure sensor used in an internal combustion engine. The method includes obtaining a plurality of samples from the manifold absolute pressure sensor. A plurality of samples is obtained from a mass airflow sensor for measuring air flow to the engine. A plurality of inferred manifold absolute pressures is estimated from the plurality of samples obtained from the mass airflow sensor. A linear functional relationship is determined between manifold absolute pressure and inferred absolute pressure from the obtained samples of the manifold pressure sensor and the estimated inferred manifold absolute pressures, such functional relationship having an offset term and a slope. A comparison is made between the determined offset term and the determined slope with a predetermined offset threshold and a predetermined slope threshold level, respectively.

Abstract: Method and apparatus for removing contaminants from internal combustion engine exhaust gas recirculation cooler. The method feeds a portion of such exhaust gasses to an input end of an exhaust gas recirculation cooler with such gases flowing through the cooler to exit an output end of the cooler. The output end is at a lower elevation then the input end with gravitational forces being imparted to the contaminants. At least a portion of the contaminants exiting the cooler are collected in a trap. The exhaust gasses exiting the trap are returned to an intake manifold of the engine. Apparatus includes: a cooler for cooling the exhaust gasses having an input port for receiving a portion of such exhaust gasses and an output port for removing the cooled gasses; and a trap coupled to the output port for collecting particulates in the exhaust gasses passing to such trap from the cooler.

Abstract: A method and system for controlling regeneration in a particulate filter coupled to an internal combustion engine. The method controls hydrocarbon injection into engine exhaust upstream of an oxidation catalyst disposed upstream of the particulate filter in accordance an algebraic sum of a feedforward term and a feedback term. The feedforward term is a function of a difference between with the engine exhaust temperature upstream of the catalyst and a predetermined desired particulate filter temperature. The feedback term is a function of a temperature of the particulate filter and the predetermined desired particulate filter temperature.

Abstract: A system and method for indicating required maintenance of an air filter used with an internal combustion engine. The system includes a throttle plate for adjusting an amount of airflow passing into cylinders of the engine. The system includes a throttle plate position sensor and a processor. The processor is responsive to a throttle plate position signal produced by the throttle plate sensor, for determining, as a function of such throttle plate position signal, whether the air filter is in need of maintenance. When a manifold absolute pressure sensor is provided, the processor is responsive to a first reading of such manifold absolute pressure sensor taken at a first time and at a second reading of the manifold absolute pressure sensor taken at a second time, for determining, as a function of a difference between such first and second readings whether the air filter is in need of maintenance.

Abstract: A low cost particulate filter pressure monitoring system and method are presented. The differential pressure across the filter is estimated based on an atmospheric pressure, a measured absolute exhaust gas pressure upstream of the first emission control device coupled to the engine and an estimated pressure drop across all other emission control devices.

Abstract: An electronically controlled valve actuator having an armature, a valve, and a coupler for coupling the actuator to the valve with motion of the armature in a first direction moving the second piston in a second direction. The actuator includes an electromagnet, an armature disposed adjacent to the electromagnetic, and a fluid-containing chamber. The fluid-containing chamber includes a first piston providing a first wall portion of the chamber and a second piston providing a second wall portion of the chamber. The first piston is coupled to the armature and the second piston is coupled to a valve. Activation of the electromagnet moves the first piston in a first direction, such motion of the first piston in the first direction driving fluid in the chamber to move the second piston in an opposite direction.

Abstract: An accurate thermodynamic model of an Active Lean NOx (ALNC) Catalyst is presented. The model takes into account hydrocarbon storage and release mechanisms of the ALNC, as well as the degradation in the ALNC hydrocarbon conversion efficiency due to ageing, and thus provides a more accurate estimate of an exotherm generated by hydrocarbon combustion in the ALNC. The estimated exotherm can them be used to detect system degradation and identify components responsible for the degradation.

Abstract: An accurate thermodynamic model of an Active Lean NOx (ALNC) Catalyst is presented. The model takes into account hydrocarbon storage and release mechanisms of the ALNC, as well as the degradation in the ALNC hydrocarbon conversion efficiency due to ageing, and thus provides a more accurate estimate of an exotherm generated by hydrocarbon combustion in the ALNC. The estimated exotherm can them be used to detect system degradation and identify components responsible for the degradation.

Abstract: A method and system for simultaneously regenerating a particulate filter coupled to an internal combustion engine and for desulfating a lean NOx trap disposed downstream of the particulate filter. The method includes adjusting at least one engine operating parameter to maintain a desired air fuel ratio for gases exiting the particulate filter in accordance with a difference between a reference set point air fuel ratio level and the air fuel ratio of gases exiting the particulate filter and wherein the reference set point level is changed between a rich air fuel ratio and a lean air fuel ratio as a function of the air fuel ratio of the gases exiting the lean NOx trap.

Abstract: A method is presented for estimating an amount of ammonia stored in a urea-based SCR catalyst based on a dynamic model of the catalyst. The model takes into account chemical and physical properties of the catalyst, such as catalyst volume, the number of available ammonia storage cites, adsorption and desorption dynamics, as well as poisoning, thermal aging, and different catalyst operating temperatures, and generates the estimate based on a measured or estimated amount of NOx in an exhaust gas mixture upstream of the catalyst, an amount of reductant injected into the catalyst to facilitate NOx reduction, and on a measured value of NOx in an exhaust gas mixture downstream of the catalyst. The estimated ammonia storage amount is then used to control the amount of reductant injected into the catalyst to maintain desired ammonia storage amount such that maximum NOx conversion efficiency coupled with minimum ammonia slip are achieved.

Abstract: A system for effective NOx control in a diesel or other lean burn internal combustion engine is presented. The system includes a urea-based SCR catalyst having an oxidation catalyst coupled upstream of it and an ALNC coupled upstream of the oxidation catalyst. This system configuration results in improved NOx conversion due to faster SCR catalyst warm-up and higher operating temperatures. Additionally, placing the ALNC upstream of the oxidation catalyst prevents hydrocarbon slip into the SCR catalyst at low exhaust gas temperatures. Also, system reliability is improved by adding an auxiliary NOx aftertreatment device.

Abstract: A system and method for monitoring a control system parameter determine a difference between a desired and estimated or measured parameter value, apply a weighting factor to the difference, and select a control strategy based on the weighted difference. The weighting factor generally reflects the confidence in the accuracy of the parameter value determined by the parameter monitor. The weighting factor may be determined based on one or more engine or ambient operating conditions or parameters, or based on statistical analyses of monitor values and/or control system parameter values, for example. In one embodiment, an engine torque monitor for an electronic throttle control system uses percent torque deviation and rate of change to select an appropriate weighting factor and determine whether a deviation between desired and estimated or measured torque selects an alternative control strategy.

Abstract: A method for diagnosing degradation in a pair of NOx sensors coupled upstream and downstream of a NOx catalyst is presented. The method is performed when catalyst temperature is such that its NOx conversion efficiency is substantially zero, such as when the catalyst temperature is very low (at cold start) or very high (e.g., following regeneration). Under those conditions, sensor degradation can be diagnosed if the upstream and downstream NOx sensor readings are not substantially the same.

Abstract: 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.

Abstract: A method and a system for improving conversion efficiency of a urea-based SCR catalyst coupled downstream of a diesel or other lean burn engine is presented. The system includes an electrically heated vaporizer unit into which a mixture of reductant and air in injected. The mixture is vaporized in the unit and introduced into the exhaust gas prior to its entering the SCR catalyst. Introducing the reductant mixed with air into the reductant delivery system prevents lacquering and soot deposits on the heated element housed inside the unit, and also speeds up the vaporization process thus reducing system response delays and improving the device conversion efficiency. The reductant delivery system is further improved by adding a hydrolyzing catalyst to it, and by isolating the reductant and air mixture from the heating element.

Abstract: 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.

Abstract: A method and a system for improved reductant delivery to an exhaust gas aftertreatment device for a lean burn internal combustion engine exhaust are presented. The system includes a heated evaporator unit into which a mixture of reductant and air in injected, wherein the mixture is vaporized and introduced into the exhaust gas aftertreatment device. Introducing the reductant mixed with air into the heated evaporator unit prevents lacquering and soot deposits on the heated element housed inside the unit, and also speeds up the vaporization process due to better reductant distribution thus reducing system response delays and improving conversion efficiency of the exhaust gas aftertreatment device. The reductant delivery system is further improved by adding a catalyst to it, and by preventing the reductant and air mixture from coming into direct contact with the surface of the heating element.

Abstract: 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.