Abstract: A start-stop system includes a fuel type module that determines a fuel type of a fuel supplied to an engine. A threshold module determines a first threshold based on the fuel type. A temperature module estimates a temperature of a catalyst of an exhaust system of the engine. A comparison module compares the temperature to the first threshold and generates a comparison signal. A power module adjusts power to a heating circuit based on the comparison signal. The heating circuit is configured to increase temperature of the catalyst. The power module adjusts the power to the heating circuit to increase the temperature of the catalyst when the engine is shutdown. An engine control module shuts down and restarts the engine to reduce idling time of the engine.

Abstract: An exhaust gas treatment system for an internal combustion engine comprises an exhaust gas conduit in fluid communication with the internal combustion engine to conduct the exhaust gas between a plurality of exhaust treatment devices. A hydrocarbon injector in fluid communication with the exhaust gas delivers hydrocarbon thereto. A selective catalyst reduction device is disposed downstream of the hydrocarbon injector and is configured to receive and mix the hydrocarbon and exhaust gas and to reduce components of NOx therein. An oxidation catalyst device is disposed in fluid communication with the exhaust gas conduit downstream of the selective catalyst reduction device and is configured to oxidize exhaust gas and hydrocarbon mixture to raise the temperature of the exhaust gas. A particulate filter assembly is located downstream of the oxidation catalyst device for receipt of the heated exhaust gas, and combustion of carbon and particulates collected in the exhaust gas filter.

Abstract: Some implementations of a system for controlling an internal combustion engine (e.g., a natural gas fired internal combustion engine or another type of engine) can include an air-fuel ratio controller that is configured to monitor sensor feedback from an exhaust path and to thereafter automatically adjust the air-fuel mixture. The system can be employed in particular methods to control emissions from the engine, for example, by reducing pollutants emitted as components of the exhaust from the engine.

Abstract: In a method for operating an air-compressing fuel-injection internal combustion engine having an exhaust gas post-treatment system with a particle filter and a nitrogen oxide reduction catalytic converter, a plurality of internal combustion engine operating settings are provided, each having respective predefined values for predefined internal combustion engine operating parameters. A heating operating setting is set when the internal combustion engine is warming up, while a basic operating setting is set in the warmed-up state. When the temperature in the exhaust gas system exceeds a predefinable first value, the heating operating setting is changed over to the basic operating setting. In the warmed-up state, at least one further (third) operating setting, with an exhaust gas recirculation rate that is reduced compared to the basic operating setting, is provided in addition to the basic operating setting.

Abstract: A method of defining a target regeneration temperature setpoint for exhaust gas upstream of a particulate filter of an exhaust gas treatment system includes as defining the regeneration temperature setpoint to include an idle temperature setpoint when the current vehicle operating mode is classified as an idle mode, and defining the regeneration temperature setpoint to include a driving temperature setpoint when the current vehicle operating mode is classified as a driving mode. The idle temperature setpoint and the driving temperature setpoint are derived individually of and separately from each other, and are based on different criteria.

Abstract: According to one embodiment, an apparatus for evaluating the condition of a NOx adsorber catalyst (NAC) of an internal combustion engine system includes a rich condition timing module, NAC outlet lambda module, and NAC condition module. The rich condition timing module is configured to accumulate the total time during which exhaust gas exiting the NAC has a lambda value less than 1.0. The NAC outlet lambda module is configured to store NAC outlet lambda values of the exhaust gas while the exhaust gas exiting the NAC has a lambda value less than 1.0. The NAC condition module is configured to evaluate the condition of the NAC based on the total time during which exhaust gas exiting the NAC has a lambda value less than 1.0 and an accumulation of the stored NAC outlet lambda values.

Abstract: A method is provided for monitoring an emission device coupled to an engine. In one example approach, the method comprises: following a deceleration fuel shut-off duration, indicating degradation of the emission device based on an amount of rich products required to cause a sensor to become richer than a threshold. The amount of rich products required may be correlated to an amount of oxygen stored in the emission device. The indication of emission device degradation may be further based on air mass and temperature during delivery of the required rich products.

Abstract: One embodiment is a method including determining whether an ammonia storage device has a stored quantity of ammonia, predicting an impending ammonia release from the ammonia storage device, determining a NOx increase amount in response to the impending ammonia release, and increasing an amount of NOx provided by an engine based on the NOx increase amount. In certain embodiments, determining the NOx increase amount in response to the impending ammonia release comprises determining a NOx increase schedule based on the stored quantity of ammonia. In certain embodiments, the NOx increase schedule comprises a specified NOx increase time period, and in certain further embodiments, the method further includes decrementing the specified NOx increase time period based on an estimated catalyst degradation value.

Abstract: A diagnostic method is provided for a particle filter arranged in exhaust-gas flow of an internal combustion engine. A particle concentration is detected by a particle sensor positioned downstream of the particle filter. The combustion-relevant engine parameters are briefly changed by an engine controller in such a way that an untreated emissions concentration from the engine is significantly increased. A filter fault message is output if the detected associated measurement values of the particle concentration exceed a detection threshold value of the particle sensor, which is in particular considerably greater than a predefined, preferably volume-related particle limit value.

Abstract: A method for abating carbon monoxide in an exhaust stream may include injecting an amount of air into the exhaust stream to produce an air/exhaust mixture; measuring an air/fuel ratio of the air/exhaust mixture; reacting carbon monoxide in the air/exhaust mixture with oxygen in the presence of a catalyst to produce carbon dioxide to abate carbon monoxide in the air/exhaust mixture; measuring a temperature of the catalyst; and adjusting the amount of air injected into the exhaust stream based on the air/fuel ratio or the temperature of the catalyst.

Abstract: A method and system for controlling a temperature of an exhaust gas being introduced to a catalyst is provided. Using an adjustable flow controller, an adjustable amount of tempering fluid is provided to the exhaust gas prior to the exhaust gas proceeding to the catalyst. A sensor senses a parameter indicative of a temperature of the exhaust gas being introduced to the catalyst. A computer processor uses a relationship to relate the parameter to an adjustment of the adjustable flow controller that will adjust the amount of tempering fluid provided to the exhaust gas and change the temperature of the exhaust gas being introduced to the catalyst toward a target temperature. Adjustment of the adjustable flow controller is initiated by the computer processor to change the flow of the tempering fluid, and the relationship between the parameter and the adjustment of the adjustable flow controller is updated.

Abstract: A powertrain includes an internal combustion engine having a combustion chamber and an aftertreatment system. A method for reducing NOx emissions in the powertrain includes monitoring an actual exhaust gas feedstream ratio of NO2 to NO, monitoring a desired exhaust gas feedstream ratio of NO2 to NO, comparing the actual and the desired exhaust gas feedstream ratios of NO2 to NO, and selectively initiating a NO2 generation cycle based upon the comparison of the actual and the desired exhaust gas feedstream ratios of NO2 to NO comprising injecting fuel mass into the combustion chamber after a primary combustion event.

Abstract: A system includes an internal combustion ignition engine with an exhaust gas flow, a particulate filter in the exhaust gas flow, a NOx reduction catalyst in the exhaust gas flow downstream of the particulate filter, a first oxygen sensor coupled to the exhaust gas flow downstream of the NOx reduction catalyst, and a second oxygen sensor coupled to the exhaust gas flow between the particulate filter and the NOx reduction catalyst. A controller includes an exhaust conditions module that interprets a first oxygen signal from the first oxygen sensor and a second oxygen signal from the second oxygen sensor and a combustion control module that commands a high engine-out air-fuel ratio when the first oxygen signal indicates a low oxygen content and commands a low engine-out air-fuel ratio when the first oxygen signal indicates a high oxygen content.

Abstract: A system for controlling regeneration in an after-treatment component comprises a feedback module, an error module, a gain module, and a regeneration control module. The feedback module is configured for determining a rate of change of the value of a controlled parameter. The error module is in communication with the feedback module and is configured for determining a value of an error term by subtracting a value of a target parameter from the value of the controlled parameter. The gain module is configured for determining a value of a proportional gain factor by raising a mathematical constant “e” to the negative power of the value of a tuned gain exponent and for determining a value of a derivative gain factor by multiplying the value of the proportional gain factor by a tuning factor. The regeneration control module is configured for determining a value of a rational control increment.

Abstract: Over a diesel engine's lifetime, engine efficiency may be reduced and some of this may be attributable to sulfur deposit accumulation in the engine. A method for controlling operation of a diesel engine operating on a fuel is provided. The method may include adjusting an injection of fuel to the engine in response to a sulfur content of the fuel.

Abstract: Methods and systems for controlling operation of exhaust of an engine including a particulate filter are described. One example method includes generating compressed air during engine operation, and storing the compressed air. The method further includes, during or after engine shutdown, pushing the compressed air through the particulate filter using a pressure of the compressed air.

Abstract: In one embodiment, a method for an engine comprises operating the engine with an upstream exhaust sensor, intermediate exhaust sensor, and downstream exhaust sensor each indicating rich, adjusting engine operation to operate the engine with an upstream exhaust sensor, intermediate exhaust sensor, and downstream exhaust sensor each indicating lean, adjusting engine operation to operate the engine with the upstream exhaust sensor indicating rich and the intermediate and downstream exhaust sensors each indicating lean, and indicating degradation of an SCR catalyst based on when the intermediate and downstream exhaust sensors switch from lean to rich.

Abstract: An object of the present invention is that after return from fuel cut, an oxygen storage amount in a catalyst in an exhaust path and an oxygen storage amount in a catalyst in an exhaust gas recirculating path are promptly adjusted to be in appropriate states, respectively. A control apparatus for an internal combustion engine of the present invention controls the internal combustion engine including a recirculating gas generating cylinder and a recirculating gas nongenerating cylinder. The control apparatus includes: an exhaust gas recirculating path for connecting the exhaust path through which exhaust gas only in the recirculating gas generating cylinder is delivered and an intake system; a recirculating catalyst provided on the exhaust gas recirculating path; and rich control means that performs rich control for controlling an air-fuel ratio to be temporarily richer than a theoretical air-fuel ratio when fuel injection is restarted after return from the fuel cut.

Abstract: A method for operating an international combustion engine, the engine also includes a first cylinder, a second cylinder, an exhaust system, and a fuel cell in the exhaust system. The method comprises operating the first cylinder lean to provide air to the fuel cell during at least one condition; and operating the second cylinder rich or stoichiometric to provide torque output and fuel to the fuel cell.

Abstract: Provided is a control apparatus for an internal combustion engine that can suppress deterioration of a catalyst that is ascribable to a control delay of a variable valve operating apparatus when transitioning to a valve stopped state accompanying a fuel-cut operation, or when transitioning from the valve stopped state to a combustion limit operating state. An intake variable valve operating apparatus capable of changing the operating state of an intake valve to a valve stopped state by continuously changing a lift amount and working angle of the intake valve is included.

Abstract: The reduction of a NOx trap upon engine shutdown is disclosed. One disclosed embodiment comprises adjusting a timing of creating a reductive environment in the exhaust conduit upstream of the lean NOx trap based upon the determined engine stop position. The creation of a reductive environment in the exhaust conduit upstream of the lean NOx trap may help to at least partially reactivate the lean NOx trap during engine shutoff.

Abstract: A method of regenerating a particulate filter that includes an electric heater is provided. The method includes determining a location of particulate matter that remains within at least one region of the particulate filter based on a regeneration event being extinguished; and selectively controlling current to a zone of a plurality of zones of the electric heater to initiate a restrike of the regeneration event based on the location of particulate matter.

Abstract: Modification of reductant (e.g., diesel exhaust fluid, DEF) tank location, for example during vehicle up-fitting may result in less than optimal operation of the DEF system due to inaccurate DEF system calibration. In one example approach, the above issue can be at least partially addressed by adjusting control system parameters for system control and diagnostics based on an input indicative of, or any modification to, the DEF tank location. In this way, DEF tank location flexibility is maintained, while also maintaining emission control and diagnostic accuracy.

Abstract: An oscillation signal is generated to oscillate the air-fuel ratio with a set frequency which is different from a 0.5th-order frequency (half of the frequency corresponding to a rotational speed of the engine). Air-fuel ratio perturbation control is performed to oscillate the air-fuel ratio according to the oscillation signal. An intensity of the 0.5th-order frequency component and the set frequency component contained in the detected air-fuel ratio signal are calculated. A determination parameter applied to determining an imbalance degree of air-fuel ratios corresponding to the plurality of cylinders is calculated according to the two intensities and determines an imbalance failure that the imbalance degree of the air-fuel ratios exceeds an acceptable limit. A predicted imbalance value, indicative of a predicted value of the imbalance degree, is calculated, and an amplitude of the oscillation signal is set according to the predicted imbalance value.

Abstract: A control apparatus according to an embodiment of the present invention comprises urea-SCR catalyst 44, a urea-water supply section 46, a low pressure gas recirculating section including a low pressure EGR pipe 61 forming a low pressure EGR passage and a low pressure EGR valve 62, and a control section. The control section controls, based on an engine operating parameter, “an amount of a fuel supplied to the engine, and an opening degree of the low pressure EGR valve.” The control section supplies the urea-water to the urea-SCR catalyst in such a manner that ammonia of an amount required for reducing nitrogen oxides contained in an exhaust gas in the urea-SCR catalyst is produced in the urea-SCR catalyst (urea-water for reducing nitrogen oxides supply control).

Abstract: An object is to provide a diesel engine that eliminates discomfort when an operator of a working, machine coupled to the diesel engine is at work while a particulate filter is being regenerated. A diesel engine includes an exhaust emission purifier and selecting means capable of selecting any one control method from isochronous control and droop control. The exhaust emission purifier includes a particulate filter and a pressure regulation valve. The particulate filter is disposed along an exhaust stream to purify exhaust gas. The pressure regulation valve is configured to apply a load onto the diesel engine so as to raise a temperature of the particulate filter so that a particulate accumulable in the particulate filter is forcibly removed and that the particulate filter is regenerated. The selecting means is configured to select the isochronous control to control the diesel engine when the load is applied by the pressure regulation valve.

Abstract: A control apparatus (100) for a gas sensor (10) which includes a cell (2) composed of a solid electrolyte body and a pair of electrodes provided thereon. The control apparatus includes voltage application means (70) for applying a single pulse voltage to the cell over a constant energization time T; first-output-value obtaining means 70 for obtaining a first output value Vri1 from the cell when a first time t1 shorter than the constant energization time has elapsed; second-output-value obtaining means (70) for obtaining a second output value Vri2 from the cell when a second time t2 shorter than the constant energization time but longer than the first time has elapsed; and deterioration-degree detection means 70 for detecting the degree of deterioration of the cell on the basis of a difference ?Vri between the second output value and the first output value.

Abstract: A catalyst heating system includes a monitoring module, a mode selection module and an electrically heated catalyst (EHC) control module. The monitoring module monitors at least one of (i) a first active volume of a catalyst assembly in an exhaust system of an engine and (ii) a first temperature of a non-EHC of the catalyst assembly. The mode selection module is configured to select a non-EHC radiant heating mode and generate a mode signal based on the at least one of the first active catalyst volume and the first temperature. An EHC control module increases temperature of the EHC to an elevated temperature that is greater than a stabilization temperature based on the mode signal. The stabilization temperature is greater than a catalyst light off temperature.

Abstract: An NOx purification system and a method for control of the NOx purification system. Two oxidation catalysts are provided upstream of an ammonia solution supply unit, and an in-cylinder fuel injection is so controlled that hydrocarbon in exhaust gas is mainly oxidized by an upstream one of the oxidation catalysts and nitric oxide in the exhaust gas is mainly oxidized by a relatively downstream one of the oxidation catalysts. NOx in the exhaust gas is purified by feeding an ammonia solution to a selective reduction NOx catalyst. The system adjusts to the concentrations of HC, NO and NO2 going to the selective reduction NOx catalyst to proper values so as to purify the NOx efficiently by the selective reduction NOx catalyst, and improve NOx purification performance in a lower temperature range.

Abstract: A method for operating a particle filter that filters particles contained in the exhaust of motor vehicle combustion engines. A conditioning step is performed such that the separation efficiency of the particle filter for particles is increased relative to the value existing in the new condition.

Abstract: A catalyst overheat prevention apparatus has a temperature obtaining portion that estimates a convergence temperature of a catalyst provided in the exhaust system of an internal combustion engine and the present temperature of the catalyst. The catalyst overheat prevention apparatus also has a fuel increment calculation portion, a comparison portion, a correction portion, and a fuel increment setting portion, which are used to execute OT fuel increase control when the convergence temperature and present catalyst temperature obtained by the temperature obtaining portion are equal to or higher than an OT determination temperature. The catalyst overheat prevention apparatus also has a present temperature correction portion that corrects the present catalyst temperature to be equal to the OT determination temperature when the present catalyst temperature is equal to or higher than the OT determination temperature and the convergence temperature is equal to the OT determination temperature.

Abstract: A method for monitoring a hydrocarbon-selective catalytic reactor device of an exhaust aftertreatment system of an internal combustion engine operating lean of stoichiometry includes injecting a reductant into an exhaust gas feedstream upstream of the hydrocarbon-selective catalytic reactor device at a predetermined mass flowrate of the reductant, and determining a space velocity associated with a predetermined forward portion of the hydrocarbon-selective catalytic reactor device. When the space velocity exceeds a predetermined threshold space velocity, a temperature differential across the predetermined forward portion of the hydrocarbon-selective catalytic reactor device is determined, and a threshold temperature as a function of the space velocity and the mass flowrate of the reductant is determined.

Abstract: Various systems and methods are provided for an exhaust gas treatment system. In one example, a system includes an exhaust gas treatment device and a wire wrapped around an exterior circumference of the exhaust gas treatment device. Continuity of the wire is monitored such that degradation of the wire due to degradation of the exhaust gas treatment device is indicated.

Abstract: Various systems and methods are described for operating an engine system having a sensor coupled to an exhaust gas recirculation system in a motor vehicle. One example method comprises during a first operating condition, directing at least some exhaust gas from an exhaust of the engine through the exhaust gas recirculation system and past the sensor to an intake of the engine and, during a second operating condition, directing at least some fresh air through the exhaust gas recirculation system and past the sensor.

Abstract: In an internal combustion engine, inside of an engine exhaust passage, air-fuel ratio sensors each of which has a solid electrolyte, electrodes which respectively cover the two side surfaces of the solid electrolyte, and a diffusion resistance layer which covers one of electrodes are arranged. In operation, the greater the amounts of deposition of sulfur ingredients at the air-fuel ratio sensors, the smaller the amounts of change of the air-fuel ratios detected by the air-fuel ratio sensor and the longer the time period of change of the air-fuel ratios. The amounts of sulfur poisoning of the air-fuel ratio sensors are detected from the changes of the air-fuel ratios detected by the air-fuel ratio sensors.

Abstract: A system for a vehicle includes a triggering module and a cylinder control module. The triggering module generates a trigger when a catalyst temperature is greater than a predetermined temperature. In response to the generation of the trigger, the cylinder control module: disables opening of an exhaust valve of a cylinder for an exhaust phase of a first combustion cycle of the cylinder; disables opening of the exhaust valve for N combustion cycles of the cylinder that follow the first combustion cycle; and enables opening of the exhaust valve for a second combustion cycle that follows the N combustion cycles. N is an integer greater than zero.

Abstract: A vehicle has an exhaust aftertreatment system including an LNT. The vehicle operates through a series of ignition cycles, deNOX cycles, and deSOX cycles. DeNOX operations begin when the LNT reaches a loading threshold. The applicable threshold depends on operating conditions, such as mean LNT temperature and mean exhaust flow rate. The thresholds are adapted based on NOX removal efficiency data. The data is compared to target values. The target values depend on the operating condition range, but remain fixed while the thresholds are adapted. NOX removal efficiency is measured over intervals corresponding to entire deNOX cycles. The data is sorted into bins according to operating conditions. The adaptations are only made if a bin has several data points accumulated over a minimum interval that is at least one ignition or deSOX cycle, preferably several. The method provides stable adaptations that compensate for aging.

Abstract: A method for operating an exhaust-gas system of an internal combustion engine having at least one particle separator and a catalytic converter, includes at least the following steps: a) carrying out processes in the internal combustion engine with lambda control about a control value; b) identifying a regeneration process of the particle separator; c) determining an oxygen demand for the regeneration process of the particle separator; and d) adapting the lambda control by the defined oxygen demand for a time period of the regeneration process of the particle separator. A motor vehicle having a spark-ignition engine and being suitable for carrying out the method, is also provided.

Abstract: An exhaust emission purifier is provided and able to suppress overheating of an exhaust emission purifying catalyst and execute fuel addition promptly when fuel addition to the exhaust emission purifying catalyst is requested. In the exhaust emission purifier of an internal combustion engine, exhaust purifying cycles are repeated in order that the exhaust emission purifying catalyst is to be regulated at a target temperature, the cycle being a combination of an addition period during which fuel is added from the fuel addition valve and a halt period during which fuel addition is halted, and the fuel addition valve is manipulated such that the halt period is disposed so as to sandwich the addition period in the cycle.

Abstract: Inside of an engine exhaust passage, a hydrocarbon feed valve (15) and an exhaust purification catalyst (13) are arranged. On the exhaust purification catalyst (13), platinum Pt (51) is carried and a basic layer (53) is formed. The concentration of hydrocarbons which flows into the exhaust purification catalyst (13) is made to vibrate within a predetermined range of amplitude and within a predetermined range of period, whereby the NOx which is contained in the exhaust gas is reduced by the exhaust purification catalyst (13). A clogging degree detecting means is provided for detecting a degree of clogging of a nozzle opening of the hydrocarbon feed valve (15). The NOx purification rate is estimated from the degree of clogging of the nozzle opening of the hydrocarbon feed valve (15) which is detected.

Abstract: An engine control system includes a catalyst module and a cylinder module. The catalyst module determines a catalyst temperature. The cylinder module selectively switches operation of a first cylinder from a first engine cycle having four strokes to a second engine cycle having N times four strokes, based on the catalyst temperature, wherein N is an integer greater than one. A related method is also provided.

Abstract: One embodiment is a unique strategy for raising exhaust temperatures which includes deactivating a first group of cylinders while maintaining a second group of cylinders in a combustion mode and injecting fuel into each of one of the second group of cylinders not earlier than 2 degrees before top dead center (TDC). The strategy also includes passing fuel rich exhaust from the second group of cylinders into an exhaust pathway and oxidizing at least a portion of the fuel rich exhaust in the exhaust pathway. In one form, the oxidizing occurs independent of any catalytic influence. Other embodiments include unique methods, systems, and apparatus for raising exhaust temperatures and/or regenerating one or more components of an aftertreatment system. Further embodiments, forms, objects, features, advantages, aspects, and benefits shall become apparent from the following description and drawings.

Abstract: A method for controlling an exhaust gas aftertreatment device of a vehicle hybrid drive is provided. The method comprises operating the hybrid drive only by a combustion engine, only by a non-combustion motor, or by both, as a function of a temperature of the exhaust aftertreatment device, and conducting exhaust gas of the hybrid drive at least partially through the exhaust aftertreatment device, the engine and motor each providing output to power the vehicle. In this way, the aftertreatment device may be operated at an optimal temperature for conversion performance.

Abstract: A method for regenerating an open particle separator includes at least determining at least one parameter, as a characteristic variable of a regeneration capability of the open particle separator. The at least one parameter is compared with a first threshold value. At least one portion of a comparison period during which the parameter has reached the first threshold value is determined. The portion is compared with a first minimum portion corresponding to a minimum regeneration time in the comparison time period. Measures are initiated to influence the parameter so that the parameter lies at least according to the first minimum portion and the first threshold value is reached and/or the open particle separator is regenerated. A motor vehicle having at least one open particle separator is also provided.

Abstract: A motor vehicle having an internal combustion engine, a differential pressure sensor or two pressure sensors for detecting a pressure difference, which may be in an exhaust tract of the internal combustion engine, and an evaluation unit for evaluating the detected pressure difference. Moreover, the present invention relates to a method for operating a motor vehicle. A controlling arrangement is provided for controlling an automatic start-stop system or an ignition system of the motor vehicle as a function of the result of the evaluation of the detected pressure difference used to detect immersion or submersion of a tailpipe of the exhaust tract in water, sludge, or a similar liquid medium in order to prevent the internal combustion engine from shutting off when the tailpipe is immersed or submerged.

Abstract: An exhaust valve assembly includes a flapper valve that is mounted on a shaft for rotation within an exhaust component housing between a closed position, an intermediate position, and an open position. An electric actuator is coupled to the shaft to control movement of the flapper valve. The electric actuator moves the flapper valve to the open position for high speed engine conditions. When engine speeds are lowered, and while all engine cylinders remain active, the electric actuator moves the flapper valve to the intermediate position. Once the flapper valve is in the intermediate position, if an engine cylinder is subsequently deactivated, the electric actuator quickly and quietly moves the flapper valve from the intermediate position to the closed position.

Abstract: A control device of an internal combustion engine is provided. A silver-alumina based catalyst device is arranged in an engine exhaust system, and an exhaust gas air-fuel ratio in the catalyst device is made rich to restore the NOX adsorption ability of the catalyst device.

Abstract: A method for reducing NOx molecules in an exhaust flow within an exhaust aftertreatment system of an internal combustion engine includes storing NOx from the exhaust flow on a NOx storage component within an aftertreatment device exposed to the exhaust flow. When the exhaust flow includes molecular hydrogen, he stored NOx is released to create ammonia in the exhaust flow. In a selective catalytic reduction device that is downstream of the aftertreatment device, the created ammonia is utilized to reduce NOx in the exhaust flow.

Abstract: A correction device for an air/fuel ratio sensor in the present invention, the sensor issuing an output according to an air/fuel ratio and installed on the downstream from catalyst of the exhaust passage, has air/fuel ratio control means for controlling an air/fuel ratio of an exhaust gas on the upstream side from a catalyst to switch between a rich air/fuel ratio which is richer and a lean air/fuel ratio which is leaner than a stoichiometric air/fuel ratio. Moreover, correction means for correcting an output of the sensor in accordance with a difference between the output of the sensor during a predetermined period during air/fuel ratio control by the air/fuel ratio control means, and a reference output corresponding to a stoichiometric air/fuel ratio, is provided.

Abstract: An exhaust gas purifying apparatus for an internal combustion engine is provided. The apparatus includes a first catalyst and a second catalyst. The first catalyst is provided in an exhaust passage of the engine, and can remove NOx in exhaust gases from the engine when an air-fuel ratio of an air-fuel mixture burning in the engine is in the vicinity of the stoichiometric ratio. The second catalyst is provided downstream of the first catalyst, an can remove NOx in the exhaust gases using a reducing agent. An execution condition of a lean operation in which the air-fuel ratio is set to a lean air-fuel ratio which is leaner than the stoichiometric ratio, is determined. When switching the air-fuel ratio from an air-fuel ratio in the vicinity of the stoichiometric ratio to the lean air-fuel ratio, the air-fuel ratio is controlled to a rich air-fuel ratio which is richer than the stoichiometric ratio, during a lean transition period from the time the execution condition is satisfied.