A catalyst degradation detection apparatus includes an air-fuel ratio detector disposed downstream of a catalyst and configured to detect an air-fuel ratio of exhaust gas flowing out from the catalyst, and an electronic control unit configured to control an air-fuel ratio of inflow exhaust gas flowing into the catalyst and determine whether the catalyst is degraded. The electronic control unit is configured to execute degradation determination control that brings the air-fuel ratio of the inflow exhaust gas to an air-fuel ratio leaner or richer than a stoichiometric air-fuel ratio. The electronic control unit is configured to determine whether precious metal of the catalyst is degraded based on the air-fuel ratio detected by the air-fuel ratio detector when an oxygen storage amount of the catalyst is varying in the degradation determination control.

A gas sensor includes a sensor element, and the sensor element includes a bottomed tubular solid electrolyte, a detection electrode provided on an outer surface of the solid electrolyte, a reference electrode provided on an inner surface of the solid electrolyte. The detection electrode of the sensor element includes a detection electrode section provided at a position on a tip side of an axial direction, an attachment electrode section provided at a position on a base end side of the axial direction, and a lead electrode section provided at a position where the detection electrode section is connected to the attachment electrode section. An insulating layer is provided between a tube of the solid electrolyte and each of the attachment electrode section and the lead electrode section.

An exhaust aftertreatment system and associated method for purifying an exhaust gas feedstream of a lean-burn or other compression-ignition internal combustion engine is described. An instruction set is executable to determine an engine-out NO2 concentration upstream of an oxidation catalyst and determine a first parameter associated with O2 concentration. A consumption of oxygen in the oxidation catalyst due to oxidation reactions is determined, and a concentration of NO2 generated by the oxidation catalyst is determined based upon the consumption of oxygen in the oxidation catalyst. A concentration of NO2 downstream of the oxidation catalyst is determined. A NO2/NOx ratio in the exhaust gas feedstream downstream of the oxidation catalyst is determined based upon the concentration of NO2 downstream of the oxidation catalyst and the NOx concentration measured by the downstream NOx sensor. The oxidation catalyst is evaluated based upon the NO2/NOx ratio.

A method (200) for ascertaining an air volume provided by means of an electric air pump (134) in an exhaust system (120) of an internal combustion engine (110), including detecting at least one activation parameter (5) of the air pump and ascertaining (220) a provided air mass flow rate (8) on the basis of a calculation specification from the at least one activation parameter (5) by utilizing an inertia of the air pump (134) and/or an inertia of the air upstream and/or downstream from the air pump (134) and/or a differential pressure from upstream from the air pump to downstream from the air pump. In addition, a processing unit and a computer program for carrying out a method (200) of this type is provided.

The invention presented is a crossover section for a vehicle exhaust system that includes a middle pipe and two outer pipes, each outer pipe in contact with and attached to the middle pipe. Diversion gates extend from the middle pipe into each of the outer pipes to divert a sample of exhaust gas into the middle pipe. A sensor, such as an oxygen sensor, is provided to measure one or more components of the combined exhaust. Also provided is an exhaust system that includes the inventive crossover section and a vehicle that includes one or more of the inventive exhaust systems.

Methods, systems, and vehicles that control the temperature of a device included in the vehicle are presented herein. The temperature of the device is controlled by ventilating the device with drivetrain air, such as transmission cooling air. In some embodiments, the device is at a greater temperature than the drivetrain air, which cools the device. In other embodiments, the device is at a lesser temperature than the drivetrain air, which heats the device. The drivetrain air is provided to the device through an exhaust duct coupled to the vehicle's transmission. The drivetrain exhaust air is preferably circulated by the transmission. The transmission may be a continuously variable transmission. The device may be an oxygen sensor that is coupled to an engine exhaust pipe. The oxygen sensor is thermally coupled to the engine exhaust and the engine exhaust pipe, which are at greater temperatures than the transmission exhaust air.

In a gas sensor, which measures a measurement pump current Ip3 of a measurement chamber, while switching a preliminary pump cell of a preliminary chamber ON or OFF at a constant period, there are formed in communication with each other sequentially from a gas introduction port in the interior of a structural body made from a solid electrolyte, a preliminary chamber, an oxygen concentration adjustment chamber, and a measurement chamber. The gas sensor rapidly determines a steady-state value of a measurement pump current Ip3, based on a peak value of a rate of change over time dIp3/dt of the measurement pump current Ip3, thereby hastening an ON/OFF switching period of the preliminary pump cell.

Various embodiments of the teachings herein include a method for determining the nitrogen oxide content and/or ammonia content in the exhaust gas of an internal combustion engine with a catalytic converter arranged in an exhaust tract and an exhaust gas sensor downstream of the catalytic converter. In some embodiments, the method comprises: determining an operating state of the internal combustion engine, the operating state indicating either lean operation or rich operation of the internal combustion engine; generating a signal using the exhaust gas sensor; and determining the nitrogen oxide content and/or ammonia content in the exhaust gas at least partially based on the determined operating state of the internal combustion engine and the signal.

In one aspect, a system is provided and includes an engine including an exhaust valve, an exhaust manifold downstream of the exhaust valve and a muffler downstream of the exhaust manifold. The system also includes a catalyst positioned downstream of the exhaust valve.

Systems, methods, and a computer readable medium are provided for monitoring and detecting a gas emission. Sensor data including gas concentration and wind data associated with a gas emission from an emission source is received from Near-Field and Far-Field sensors configured within a gas production and distribution environment. The sensor data can be provided as inputs to a Near-Field dispersion model to determine an emission rate associated with the gas emission and one or more source locations associated with the gas emission. The emission rate can be included in emission data and provided for output. Related apparatus, systems, techniques, and articles are also described.