A method for estimating the ageing of an exhaust gas sensor (16) placed in an exhaust line (14) of a diesel internal combustion engine (10) of an industrial vehicle (1) includes—acquiring (S100) an initial value of an estimated remaining lifetime (50) of the exhaust gas sensor;—measuring (S102) the time spent by the engine in each of several predefined engine operation modes during a predefined time period;—for each of the engine operation modes, calculating (S104) a lifetime loss value depending on the time spent by the engine in said engine operation mode during the predefined time period and on a predefined ageing rate associated to said engine operation mode;—updating (S106) the estimated remaining lifetime value by subtracting each calculated lifetime loss value from the initial value.

The invention relates to a method for exhaust gas aftertreatment in an internal combustion engine. For purposes of the exhaust gas aftertreatment in the internal combustion engine, an exhaust gas system is provided in which a first three-way catalytic converter is arranged, as seen in the direction in which the exhaust gas of the internal combustion engine flows through the exhaust gas system, while at least another three-way catalytic converter is arranged downstream from the first three-way catalytic converter. Here, at least one lambda probe is arranged in an exhaust gas channel of the exhaust gas system upstream from the appertaining three-way catalytic converters. In the proposed method, a component temperature of the three-way catalytic converters is determined and compared to a light-OFF temperature. In this process, the lambda control of the internal combustion engine is carried out by means of the lambda probe upstream from the last three-way catalytic converter that has reached its light-OFF temperature. Moreover, according to the invention, an exhaust gas aftertreatment system for carrying out such a method is being proposed.

A filling of an exhaust gas component storage of a catalytic converter is regulated. An actual fill level of the exhaust gas component storage is ascertained using a first system model, and a base lambda setpoint value for a first control loop is predefined by a second control loop. An initial value for the base lambda setpoint value is converted into a fictitious fill level, the fictitious fill level being compared with a setpoint value for the fill level output, and the base lambda setpoint value being iteratively changed as a function of the comparison result, if a difference between the setpoint value for the fill level and the fictitious fill level is greater than a predefined degree. The base lambda setpoint value is not changed if no difference exists between the setpoint value for the fill level and the fictitious fill level.

A misfire detection device for an internal combustion engine includes a storage device and processing circuitry, the storage device stores first mapping data corresponding to a case where a warm-up process of a catalyst provided in an exhaust passage of an internal combustion engine is being executed, and second mapping data corresponding to a case where the warm-up process is not being executed, and each of the first mapping data and the second mapping data uses a rotation waveform variable as an input and defines a mapping that outputs a misfire variable that is a variable related to a probability misfire has occurred. The rotation waveform variable is a variable indicating a difference between a plurality of values of an instantaneous speed variable respectively corresponding to a plurality of different minute angular intervals.

Various methods and systems are provided for controlling emissions. In one example, a controller is configured to respond to a sensed exhaust oxygen concentration by changing a fuel injection timing to maintain particulate matter (PM) within a range, and then adjusting an exhaust gas recirculation (EGR) amount based on NOx sensor output and based on the change in fuel injection timing.

A control device for an exhaust sensor is configured to control the exhaust sensor disposed in an exhaust passage of an internal combustion engine. The control device for an exhaust sensor includes: a sensor element; a heater configured to heat the sensor element; a current detection circuit configured to detect an output current of the exhaust sensor, and an electronic control device configured to control electric power that is supplied to the heater by PWM control.

A method for diagnosing a plurality of lambda sensors which are arranged upstream of an exhaust gas catalytic converter in a plurality of exhaust gas banks of a multi-flow exhaust gas system of an internal combustion engine. An opposite lambda offset of the lambda sensors is identified (54) when a difference (ΔT) between a measured exhaust gas temperature (T.sub.measure) and a modeled exhaust gas temperature (T.sub.mod) downstream of the exhaust gas catalytic converter overshoots a threshold value (S).

An engine control device is provided, which includes an engine body where a cylinder is formed, an exhaust passage through which exhaust gas discharged from the engine body circulates, a NO.sub.x sensor disposed in the exhaust passage and configured to detect a concentration of NO.sub.x in the exhaust gas, an injector configured to change an air-fuel ratio inside the cylinder, an in-cylinder temperature changer configured to change a temperature inside the cylinder, and a controller configured to control the injector and the exhaust shutter valve. The controller controls the injector based on a detection value of the NO.sub.x sensor to variably set the air-fuel ratio inside the cylinder, and when a particular condition that the air-fuel ratio inside the cylinder is leaner than a preset upper limit is satisfied, and causes the in-cylinder temperature changer to raise the temperature inside the cylinder.

A method of operating an oxygen sensor system is provided where the system includes an oxygen sensor, the oxygen sensor including a pump cell, and wherein the oxygen sensor is connected to associated circuitry such that the associated circuitry controls operation of the pump cell. The pump cell includes a pump line connected to a pump electrode of the pump cell and a return line connected to a return electrode of the pump cell. The method includes, subsequent to a diagnostic process, raising the potential of the pump line for a predetermined period of time by injecting current onto the pump line.

An air-fuel ratio control system (1) including an air-fuel ratio control section (3) for controlling the air-fuel ratio λ of an air-fuel mixture, an exhaust gas purifier (4); an air-fuel ratio sensor (5) whose output changes sharply when λ in the exhaust gas changes between rich and lean sides about a stoichiometric air-fuel ratio; a heater (6); and a temperature control section (7). The air-fuel ratio control section (3) controls λ based on the output of the air-fuel ratio sensor (5) using, as a target air-fuel ratio, a predetermined air-fuel ratio such that 0.980≤λ<1.000 is satisfied, and when a change amount Δλ λ is 0.008, an output difference ΔV is 150 mV or smaller. The temperature control section (7) controls the temperature of the air-fuel ratio sensor (5) to a predetermined target temperature of 650° C. or higher.