Abstract: A device is designed for determining a pre-set air/fuel ratio in the combustion chamber of a cylinder of an internal combustion engine. The device is further designed for determining a filtered, pre-set air/fuel ratio in the combustion chamber of the cylinder by filtering the pre-set air/fuel ratio in the combustion chamber of the cylinder by means of a filter which models the dynamic behavior of the upstream region of the exhaust gas catalyst relative to the arrangement of the exhaust gas probe in the exhaust gas catalyst, in particular its storage, reduction and/or oxidation properties. The device is further designed for determining an adjustable variable by means of a regulator as a function of the filtered and pre-set air/fuel ratio, and of a sensed air/fuel ratio in the combustion chamber of the cylinder.

Abstract: The invention relates to a method for operating an internal combustion engine that is equipped with a three-way catalytic converter. According to the inventive method, a lambda value of the air/fuel mixture, with which the internal combustion engine is supplied, is set below and above a set value in a cyclically alternating manner during a forced activation whereby the lambda value in rich phases is less than the set value and in lean phases, is greater than the set value. During the forced activation, the rich phases and the lean phases are matched to one another according to a specified criterion. The invention provides that the amount, by which the lambda value in rich phases is set below the set value, is selected so that it is equal to the amount, by which the lambda value in lean phases is set above the set value. When determining the criterion, an air mass is used that is supplied to the internal combustion engine during the rich and lean phases.

Abstract: An exhaust gas probe is disposed downstream of a catalytic converter in an exhaust gas tract of an internal combustion engine. A first quality value which is representative of a signal dynamic of the measured signal of the exhaust gas probe is determined as a function of the measured signal of the exhaust gas probe. If the first quality value represents at least one predefined signal dynamic, the exhaust gas probe is diagnosed as functioning correctly. If the first quality value does not represent at least the predefined signal dynamic, a catalytic converter diagnosis is performed comprising a loading with oxygen and/or an emptying of oxygen with at least two different air/fuel ratios. Dependent on the catalytic converter diagnosis, the exhaust gas probe is diagnosed as functioning either correctly or incorrectly.

Abstract: To operate an internal combustion engine subvolumes of the fluid flowing into an intake duct in each instance during a predetermined time period are determined for each period. Tank purging values of a characteristic quantity are determined for each period. The characteristic quantity is representative of a tank purging fuel mass, which flowed through the tank purging valve in each instance during the predetermined time period. The successive subvolumes are added together, starting from the currently determined subvolume, to give a total subvolume, until the total subvolume is greater than or equal to an effective intake duct volume downstream of the tank purging valve.

Abstract: Disclosed is an internal combustion engine comprising at least one cylinder and an exhaust manifold in which a catalytic converter, a first exhaust gas probe, and a second exhaust gas probe are disposed. The first exhaust probe is located upstream from the catalytic converter while the second exhaust gas probe is arranged downstream therefrom. A lambda Controller is provided which is configured so as to determine a lambda correction factor in accordance with a first test signal that is assigned to the first exhaust gas probe. A trim controller is provided to which a setpoint value and an actual value of a second test signal allocated to the second exhaust gas probe are fed as a control difference. The trim controller is configured so as to determine a proportionate corrective factor.

Abstract: The invention relates to a method for diagnosing a regulated exhaust gas catalyst, according to which regulating the catalyst results in control cycles, catalyst diagnosis being performed at a predetermined oxygen concentration per control cycle. A fuel mixture can be adjusted fat or lean according to a specific lambda control factor. A fat or lean exhaust gas is detected, the lambda control factor being incrementally decreased when a lean exhaust gas is detected. The lambda control factor is modified by a P step following a detected change from a fat to lean exhaust gas or from a lean to a fat exhaust gas, the lambda control factor being set to a minimum value during a first loading period following a detected change from a fat exhaust gas to a lean exhaust gas while being set to a maximum value during a second loading period following a detected change from a lean exhaust gas to a fat exhaust gas.

Abstract: The invention relates to a waste gas probe which is disposed in an internal combustion engine, comprising a plurality of cylinders and injection valves associated with the cylinders, in order to measure fuel. The waste gas probe is arranged in a waste gas tract and the measuring signal thereof is characteristic for the air/fuel ratio in the respective cylinder. The measuring signal is detected in relation to a reference position of the piston of the respective cylinder at a predefined crankshaft angle and associated with a respective cylinder. A manipulated variable which is used to influence the air/fuel ration in the respective cylinder according to the measuring signal detected for the respective cylinder is produced by a controller. The predefined crankshaft angle is adapted according to an instability criterion of the controller.

Abstract: The invention relates to a device for controlling an internal combustion engine, comprising a first regulator, whose regulating difference is the difference of an actual value and an estimated value of individual cylinder deviation of the air/fuel ratio from a preset air/fuel ratio. The first regulator also has an integral regulating parameter, its manipulated variable being a first estimated value. A second regulator is also provided, the regulating difference of which is the first estimated value. Said regulator has a proportional regulating parameter whose manipulated variable is an individual cylinder lambda regulating factor. A PT1 filter is additionally provided, by means of which a second estimated value is determined through PT1 filtering of the individual cylinder lambda regulating factor.

Abstract: The invention relates to a device for controlling an internal combustion engine, comprising a first regulator, whose regulating difference is the difference of an actual value and an estimated value of individual cylinder deviation of the air/fuel ratio from a preset air/fuel ratio. The first regulator also has an integral regulating parameter, its manipulated variable being a first estimated value. A second regulator is also provided, the regulating difference of which is the first estimated value. Said regulator has a proportional regulating parameter whose manipulated variable is an individual cylinder lambda regulating factor. A PTI filter is additionally provided, by means of which a second estimated value is determined through PT1 filtering of the individual cylinder lambda regulating factor.

Abstract: In order to average the continuously sampled individual values of the measuring signal through totaling over a summation period (TP1, TP2), said period corresponding to the period, dependent on engine speed, of pressure pulsations of the exhaust, while at the same time sparing the memory resources, it is proposed for totaling to be carried out across the N1 individual values block-by-block and already to start before signal updating so that the block values already formed continuously block-by-block up to the update time (tn) and buffered instead of the respective individual values are used for calculating an average.

Abstract: A method for checking an exhaust gas cleaning plant connected to an internal combustion engine in an exhaust gas tract that includes a catalytic converter having oxygen storage characteristics as well as a NOx sensor positioned downstream in the exhaust gas tract that emits a sensor signal depending on the NOx and the NH3 concentration in the exhaust gas in which case the internal-combustion engine is operated with a periodic air/fuel ratio oscillating around the value lambda=1 and that the average of the sensor signal is formed over one period or several periods and if the threshold value of the average is exceeded, damage to the monolith of the catalytic converter is detected.

Abstract: A method for purifying the exhaust gas from an internal combustion engine, which is operated under lambda-based closed loop control and which has an exhaust gas tract in which is located a catalytic converter, is provided. According to this method, a pre-converter lambda value for the exhaust gas is continuously sensed upstream of the catalytic converter, from which a pre-converter lambda signal is generated, and this pre-converter lambda signal is used as the reference variable for the lambda control loop. A post-converter lambda value for the exhaust gas is continuously sensed downstream from the converter, from which a post-converter lambda signal is generated, this being a monotonically decreasing function of the lambda value for the exhaust gas downstream from the catalytic converter.

Abstract: An exhaust-gas cleaning system for an internal-combustion engine has an exhaust-gas cleaning element, a first exhaust-gas sensor located upstream from the exhaust-gas cleaning element, and a control unit with an input connected to a first exhaust-gas sensor. The output of the control unit is connected to an engine management system for controlling the composition of the mixture in the internal-combustion engine as a function of the exhaust-gas composition that is measured by the first exhaust-gas sensor. A second exhaust-gas sensor has an output connected to the control unit. The second exhaust-gas sensor is arranged in the exhaust-gas stream of the internal-combustion engine, and is arranged downstream of the exhaust-gas cleaning element. The second gas sensor enables the control unit to cause a modification of the local balance of the oxygen concentration in the exhaust-gas cleaning element.

Abstract: A method for diagnosing an exhaust gas cleaning system of a lambda-controlled internal combustion engine where a catalyst is subjected to a specific oxygen load which is greater than the normal operating load, by increasing the surface covered by the oscillation of a signal of a pre-catalyst lambda probe according to a set value. The exhaust gas cleaning system can be tested by evaluating the oscillation of a signal of a post-catalyst lambda probe. In the event this diagnosis shows a defect in the exhaust gas cleaning system without the area covered by the oscillation of the probe signal of the pre-catalyst lambda probe having had to be increased to or beyond a set value, the pre-catalyst lambda probe is defective. Otherwise, it can be concluded that the catalyst is defective.

Abstract: For a three-way catalytic converter system with a preliminary catalytic converter, a main catalytic converter and an oxygen sensor with a constant characteristic curve disposed between the two catalytic converters, a method for resetting the oxygen concentration in the preliminary catalytic converter and the main catalytic converter in the event of a transition from lean-burn operation to stoichiometric operation includes exposing both catalytic converters to a rich mix until the desired oxygen concentrations have been reached. In the process, the constant measurement signal from the oxygen sensor and the measurement signal from an air mass flow meter are used to calculate the quantity of oxygen that is released to the exhaust gas from the main catalytic converter, in order to end rich-burn operation when a predetermined desired value is reached.

Abstract: A process for cleaning exhaust gas flow from an internal combustion engine using a catalyst, a lambda probe is disposed in the exhaust gas flow upstream from the catalyst and is connected to a controller that actuates the lambda probe, the controller receives a raw signal output from the lambda probe and forms a measurement signal that is supplied to control the internal combustion engine. The process includes regulating operation of the internal combustion engine such that a predetermined value of the lambda probe corresponds to a certain level of the measurement signal. Trimming the certain level of the measurement signal by a set value determined with an additional measuring pickup located downstream of the catalyst is performed, the trimming corrects the certain level of the measurement signal that corresponds to the predetermined value of the lambda probe.

Abstract: A method of monitoring the dynamic operability of a lambda sensor (monitor sensor), disposed in the exhaust gas stream of an internal combustion engine downstream of a catalytic converter. Once the engine operating state of overrun fuel cutoff is detected, the rich/lean switching time of the monitor sensor disposed downstream of the catalytic converter is ascertained and weighted as a function of the air flow rate (LMM) in the intake conduit. By comparing the mean value of the thus-obtained switching time with a limit value and ensuing evaluation, the operability of the monitor sensor is diagnosed. Operability is assured if the switching time is below the limit value. Other diagnostic criteria are formed by evaluating the signal level of the monitor sensor.

Abstract: A process for cleaning exhaust gas flow from an internal combustion engine using a catalyst, a lambda probe is disposed in the exhaust gas flow upstream from the catalyst and is connected to a controller that actuates the lambda probe, the controller receives a raw signal output from the lambda probe and forms a measurement signal that is supplied to control the internal combustion engine. The process includes regulating operation of the internal combustion engine such that a predetermined value of the lambda probe corresponds to a certain level of the measurement signal. Trimming the certain level of the measurement signal by a set value determined with an additional measuring pickup located downstream of the catalyst is performed, the trimming corrects the certain level of the measurement signal that corresponds to the predetermined value of the lambda probe.

Abstract: A device for setting movement behavior of gas-exchange valves of an internal combustion engine with a camshaft. The device has a control unit that generates a setting signal for a setting element of a setting device that adjusts the camshaft. A pilot control system is provided which additively corrects the setting signal including determining an estimated value for adjusting the camshaft without taking account of the delay time of the setting device.

Abstract: Periodic forced stimulations are asserted on setpoint values for a lambda control and a system response of a lambda control loop is simulated by a model that includes a sensor delay time as the model parameter. Amplitude gains of the model and the system are compared with each other and adapted according to the result of the comparison of the model parameters. If the adaptation value lies above a threshold, a lambda probe is classified as defective.