Various embodiments include a method of ascertaining the oxygen load of a catalytic converter disposed in an exhaust tract of an internal combustion engine with an exhaust gas sensor is disposed downstream of the catalytic converter comprising: generating a signal using the exhaust gas sensor indicating a proportion of nitrogen oxide and/or ammonia in the exhaust gas; and ascertaining the oxygen load of the catalytic converter at least partly on the basis of the signal from the exhaust gas sensor.

Provided is a method for diagnosing whether an oxidation catalyst has degraded, based on an output value from one diagnostic sensor with higher accuracy. When a ratio of nitrogen monoxide that is oxidized by a catalyst and discharged downstream of the catalyst as nitrogen dioxide, with respect to nitrogen monoxide contained in an exhaust gas supplied upstream of the catalyst in an exhaust path is defined as a NO conversion rate, a diagnostic sensor configured to output an electromotive force corresponding to the NO conversion rate as a diagnostic output is provided downstream of the catalyst in the exhaust path, and whether the catalyst has degraded beyond an acceptable limit is diagnosed by comparing the diagnostic output with a threshold value predetermined depending on a temperature of the catalyst.

A control device for an internal combustion engine is provided with a target air-fuel ratio setting part including a first setting control part performing normal control alternately switching a target air-fuel ratio between a predetermined first lean air-fuel ratio and a predetermined first rich air-fuel ratio and a second setting control part performing control for restoration of the storage amount stopping normal control and increasing the oxygen storage amount of a second catalyst when an output air-fuel ratio of a third air-fuel ratio sensor becomes a predetermined rich judgment air-fuel ratio or less. Further, the second setting control part is configured to set the target air-fuel ratio to a predetermined second lean air-fuel ratio larger than the first lean air-fuel ratio at the time of start of the control for restoration of the storage amount and set the target air-fuel ratio to a predetermined third lean air-fuel ratio smaller than the second lean air-fuel ratio after an exhaust with a larger air-fuel ratio than the stoichiometric air-fuel ratio flows out from the first catalyst in the time period of setting the target air-fuel ratio to the second lean air-fuel ratio.

A fine particle detector includes: a casing part configured to accommodate an object to be heated; an electromagnetic wave generating part configured to generate electromagnetic waves of different frequencies; at least one power sensor configured to measure powers, from the casing part, of the electromagnetic waves that have entered into the casing part; and a fine particle detection controlling part configured to determine, based on the powers of the electromagnetic waves of the different frequencies measured by the at least one power sensor, whether an accumulated amount of fine particles accumulated in the object to be heated is greater than or equal to a predetermined accumulated amount.

A method to control an internal combustion engine having an exhaust duct and an exhaust gas after-treatment system comprising at least one catalytic converter arranged along the exhaust duct; an oxygen sensor housed along the exhaust duct and arranged upstream of said at least one catalytic converter; and a burner suited to introduce the exhaust gases into the exhaust duct upstream of the oxygen sensor the method provides the steps of calculating the thermal power required to reach the nominal operating temperature of said at least one catalytic converter obtained with an objective value of the air/fuel ratio value; and determining both the objective fuel flow rate and the objective air flow rate to be fed to the burner to obtain the thermal power required to reach the nominal operating temperature of said at least one catalytic converter.

A first gas sensor having a first sensor element includes a first protective cover that protects the first sensor element, and a second gas sensor having a second sensor element includes a second protective cover that protects the second sensor element. The first protective cover is coated with an oxidation catalyst for one target component from among a plurality of target components, and the second protective cover is coated with an inert catalyst for the one target component.

A method includes calculating whether a quantity of the PMs accumulated in a PF is at or above a risk level at which damage to the PF is caused when reproducing the PF, calculating a driving condition index by accumulating a weighting factor for a driving condition under which there is a likelihood of causing the damage to the PF, when the amount of accumulated PMs is at or above the risk level; calculating a temperature index in accordance with a temperature of the PF and a PM index in accordance with the quantity of the accumulated PMs when the quantity of the accumulated PMs is at or above the risk level; calculating a degradation condition index considering the driving condition index, the temperature of the PF, and the quantity of accumulated PMs; and changing a reproduction periodicity of the PF according to the degradation condition index.

A muffler heat protection system for a vehicle includes a muffler heat shield configured to extend circumferentially around a portion of a muffler, the muffler heat shield having a first end and a second end; a heat shield extension secured to the first end of the muffler heat shield; a double wall exhaust pipe including an inner exhaust pipe and an outer covering pipe disposed over the inner exhaust pipe, the outer covering pipe having a first end portion and a second end portion, and the inner exhaust pipe having a first end portion and a second end portion; wherein the second end portion of the outer covering pipe is welded to the muffler at a welded connection seam; and wherein the heat shield extension projects outward from the muffler heat shield over the welded connection seam.

A method for ascertaining an exhaust gas composition of an exhaust gas of an internal combustion engine with regard to an ammonia fraction and a nitrogen oxides fraction in an exhaust gas system including an SCR catalytic converter. The method includes detecting, using a sensor, a first signal whose magnitude is a function of the nitrogen oxides fraction of the exhaust gas upstream from the SCR catalytic converter, detecting using a sensor a second signal whose magnitude is a function of the ammonia fraction and the nitrogen oxides fraction of the exhaust gas downstream from the SCR catalytic converter, storing the two signals over an observation period, and ascertaining the ammonia fraction and optionally the nitrogen oxides fraction of the exhaust gas downstream from the at least one SCR catalytic converter using a calculation rule that uses the two signals during the observation period as input variables.

An internal combustion engine arrangement includes an internal combustion engine, a catalytic converter, and a controller. The controller is configured to determine a maximum H.sub.2 production capacity of the catalytic converter. The catalytic converter is arranged downstream of the internal combustion engine. The controller is configured and adapted to determine the maximum H.sub.2 production capacity of the catalytic converter based on a first function that correlates an H.sub.2 production of the internal combustion engine with first internal combustion engine parameters.