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: 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 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: The invention relates to a method for regenerating a particulate filter, which is mounted inside the exhaust gas channel of an internal combustion engine, filters particles out of the exhaust gas flowing inside of the exhaust gas channel, and which is intermittently regenerated during operation. According to the method, the actual air mass flow (Lexp) supplied to the internal combustion engine is measured, and the air requirement (Lcalc) of the internal combustion engine is determined. A regeneration of the particulate filter is initiated based on a difference (?L) between the air mass flow and the air requirement.

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: 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: 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: 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 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: The invention relates to 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, whereby 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, and 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, and where the post-converter lambda signal is used in a trimming control loop to apply a correction to the lambda control loop, whereby a measurement signal is generated which, at least below a certain value of lambda close to

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: 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 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: 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 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.

Abstract: A method for calculating an actual fresh-air mass flowing into a cylinder with the aid of an inlet pipe flow model. The description of the flow model is based on a nonlinear differential equation. The chosen model approach contains modeling of an external exhaust-gas recycling system, variable inlet systems and systems with variable control valves. The model-assisted load detection method can be used in engine control systems based on air mass flow and on inlet pipe pressure. A correction algorithm, in the form of a model control loop allows permanent improvement of accuracy when the model parameters are inexact. That is to say model balancing is provided in steady and unsteady operational states.

Abstract: A method for determining an air mass flow into cylinders of an internal combustion engine with the aid of a model includes calculating an air mass actually flowing into a cylinder with the aid of an intake tube filling model supplying a load variable on the basis of which an injection time is determined, from input variables relating to throttle opening angle and ambient pressure and from parameters representing valve control. The load variable is used for prediction in order to estimate the load variable at an instant which is at least one sampling step later than a current calculation of the injection time.