Provided is an exhaust gas purification apparatus having a control device that monitors the transition of a detection value of each of an upstream NOx sensor and a downstream NOx sensor, and when the NOx purification rate of the SCR catalyst falls to a value of a first threshold or lower, generates an abnormality detection signal indicating that an over storage state has occurred in an SCR catalyst if the amount of change in the detection value of the upstream NOx sensor per unit time is at least a second threshold and the amount of change in the detection value of the downstream NOx sensor per unit time is at most a third threshold.

Methods and systems are provided for an exhaust system. In one example, a method may include determining presence of a zone flow based on a comparison of a first exhaust sensor and a second exhaust sensor. The presence or absence of the zone flow may determine a rate at which an air-fuel ratio is adjusted.

An aftertreatment system for a diesel engine may include a diesel particulate filter configured for placement in fluid communication with the diesel engine to receive an exhaust flow. The system may also include a selective catalytic reduction system configured for arrangement downstream of the diesel particulate filter and a NO.sub.x sensor configured to measure a NO.sub.x concentration in the exhaust flow entering the selective catalytic reduction system. The system may also include a controller configured to estimate a ratio of NO.sub.2 to NO.sub.x downstream of the diesel particulate filter and based on a factor affecting the generation of NO.sub.2 upstream of the selective catalytic reduction system. The controller may also be configured to adjust the measured NO.sub.x concentration based on the ratio to provide an estimated actual NO.sub.x concentration and dose diesel exhaust fuel into the exhaust flow based on the estimated actual NO.sub.x concentration.

The disclosure relates to a method for checking and ensuring the functionality of an exhaust gas aftertreatment system of an internal combustion engine. The exhaust gas aftertreatment system has a catalytic converter and a voltage source. The catalytic converter has a catalytic converter area and an electrical heating device which is selectively supplied with electrical energy from the voltage source. The method includes determining an actual value which is characteristic of an ohmic resistance of the heating device. The actual value being determined by using an electrical current strength supplied to the heating device and an electrical voltage supplied to the heating device from the voltage source. The method also includes providing a setpoint value which is characteristic of an expected ohmic resistance of the heating device. The setpoint value takes into account a specific heating-up behavior of the heating device and an expected long-term behavior of the catalytic converter.

A heavy duty truck includes a diesel engine, an exhaust after-treatment system, and an engine control unit. The exhaust after-treatment system may include one or more selective catalytic reduction systems, each with a respective heater, and each heater with a respective pair of temperature sensors, one upstream and the other downstream of the heater. Such systems may be used to perform diagnostic methods including populating a lookup table having heat energy supplied to an exhaust gas stream by the diesel engine as a first independent variable, heat energy supplied to the exhaust gas stream by a heater as a second independent variable, and a resulting temperature as an output. Such a lookup table can be used to maintain a temperature of the exhaust gas flow at a constant target temperature.

Provided is an exhaust gas purification apparatus having a control device that monitors the transition of a detection value of each of an upstream NOx sensor and a downstream NOx sensor, and when the NOx purification rate of the SCR catalyst falls to a value of a first threshold or lower, generates an abnormality detection signal indicating that an over storage state has occurred in an SCR catalyst if the amount of change in the detection value of the upstream NOx sensor per unit time is at least a second threshold and the amount of change in the detection value of the downstream NOx sensor per unit time is at most a third threshold.

The preferred invention is directed to a controller for a vehicle exhaust valve. The controller comprises a vehicle interface for determining a live value for an operating parameter of a vehicle, a recording module being configured to, upon activation, instantaneously record the live value of the operating parameter, and a programming module for determining a value range based on the recorded live value and allowing a desired position of the valve to be set such that during operation, the control system automatically moves the valve to the desired position when the operating parameter is within the value range.

A method for estimating a quality of reductant in an engine aftertreatment system for an engine using a virtual sensor, the method comprising: determining whether an enablement condition is met, wherein the enablement condition is one or more of: a reductant fill condition determined based on data received from one or more float sensors associated with the engine; a machine start condition determined based on machine speed data obtained from a speed sensor associated with the engine; and/or a rationality check condition determined based on data associated with a fault of one or more sensors associated with the engine; upon determining that the enablement condition is met, receiving NOx measurement data obtained from at least one NOx sensor; generating a reductant quality value based on the NOx measurement data; and outputting a reductant quality determination based on the reductant quality value.

A method for estimating a quality of reductant in an engine aftertreatment system for an engine using a virtual sensor, the method comprising: determining whether an enablement condition is met, wherein the enablement condition is one or more of: a reductant fill condition determined based on data received from one or more float sensors associated with the engine; a machine start condition determined based on machine speed data obtained from a speed sensor associated with the engine; and/or a rationality check condition determined based on data associated with a fault of one or more sensors associated with the engine; upon determining that the enablement condition is met, receiving NOx measurement data obtained from at least one NOx sensor; generating a reductant quality value based on the NOx measurement data; and outputting a reductant quality determination based on the reductant quality value.

A computer for a vehicle, the vehicle including a heat engine, a depollution system configured to depollute the exhaust gases originating from the engine, a first probe placed between the outlet of the heat engine and the inlet of the depollution system and configured to measure a first parameter relating to the oxygen level in the exhaust gases exiting the heat engine, a second probe placed at the outlet of the depollution system and configured to measure a second parameter relating to the oxygen level in the exhaust gases exiting the depollution system. The computer being configured to receive the values measured by the first probe and by the second probe over a predefined measurement time interval and to diagnose clogging of the first probe.