Abstract: The invention is directed to a method for controlling the composition of the air/fuel mixture for an internal combustion engine. In the method, the mean value of the control oscillation is influenced via a change of the delay times tv with which a sign reversal of the actuating variable change is delayed. The dead time of the control is determined from the time-dependent performance of the control actuating variable and is considered for the change of the delay times tv.

Abstract: The invention is directed to a method and an arrangement for controlling the torque outputted by an internal combustion engine while deactivating individual cylinders. A desired value for the torque outputted is obtained by suppressing and resuming the metering of fuel to at least one cylinder as well as by adjusting the ignition angle. The deactivation and reactivation of the cylinders and the adjustment of the ignition angle are synchronized.

Abstract: The invention is directed to a method for interrupting fuel metered to an engine during overrun operation. The engine is equipped with a catalytic converter and the method includes the steps of: determining a criterion for the temperature of the catalytic converter; checking to determine if the criterion satisfies a condition for the temperature of the catalytic converter which is characteristic for a high temperature of the catalytic converter; and, interrupting the metering of fuel to the engine when the condition is not satisfied.

Abstract: A method for monitoring the starting behavior of a catalytic conversion system by placing an apparatus in the exhaust-gas pipe of an internal combustion engine. The conversion power of the starting region can be determined from the temperature which results when an air/fuel mixture is fed to the catalytic conversion system.

Abstract: A method and device for monitoring a heating device of a sensor mounted in the exhaust system of an internal combustion engine. In assessing the working order of the heating device, use is made of the fact that a sensor heated by a heating element heats up more strongly than an unheated sensor, and that it is possible to establish, with the aid of the signals output by the sensor, whether the sensor has exceeded its minimum operating temperature. The temperature of the sensor is simulated as a function of internal combustion engine operating characteristics. The working order of the heating device can be assessed with the aid of the simulated temperature and the information as to whether the minimum operating temperature is exceeded.

Abstract: A method and device for generating a simulated signal relating to a temperature in the exhaust system of a motor vehicle. By means of a characteristic curve or a characteristic diagram, a signal for a steady state exhaust gas temperature is generated as a function of the flow rate of gas through the internal combustion engine of the motor vehicle. This signal is further processed to generate a signal for a rapid portion and to form a signal for a slow portion of the exhaust gas temperature. The signals for the two portions are superimposed with a prescribable weighting to generate a signal for the exhaust gas temperature. The signal for the slow portion can be logically connected, before the superimposition, to a correction value which depends on the speed of the vehicle.

Abstract: A method and device for forming a signal relating to a temperature in the exhaust system of an internal combustion engine. The method can be used, for example, to form a signal for the exhaust gas temperature upstream of the catalytic converter, a signal for the temperature in the catalytic converter, or a signal for the temperature downstream of the catalytic converter. The first step is to form a signal for a steady-state exhaust gas temperature as a function of at least one operating characteristic of the internal combustion engine. This signal can be subjected to a series of corrections in order to take into account parameters such as the efficiency of the internal combustion engine, the air/fuel ratio, the temperature of the intake air, the mixture flow rate, the vehicle speed, a possibly activated cylinder cutout, and the presence of condensed water in the exhaust system.

Abstract: A system for operating a heating element (114) of a ceramic sensor (112) which is arranged in the exhaust channel (104) of an internal combustion engine (100) and which can be heated by the heating element (114). If the internal combustion engine (100) is in an operating state in which it can be assumed that liquid is present in the exhaust channel (114) of the internal combustion engine (100), the heating element (114) is not activated or is triggered such that the ceramic sensor (112) is operated below a critical temperature (TSeK). Above the critical temperature (TSeK) there is a risk that the ceramic sensor (112) will be damaged due to contact with liquid.

Abstract: A method and a device for forming a simulated signal of the temperature of the exhaust gas, exhaust gas sensor or catalytic converter for an internal combustion engine. Using a temperature characteristic depending on the air mass stream, and two low-pass filters with time constants depending on the air mass stream, the exhaust gas temperature upstream from the catalytic converter, the exhaust gas sensor temperature and the catalytic converter temperature are simulated. The air mass, integrated since the time the internal combustion engine is started, is compared with two threshold values to determine whether or not there is still condensation water present in the exhaust gas channel upstream from the catalytic converter and/or in the catalytic converter itself. If condensation water is present, the simulated temperature(s) is limited to a value of approximately 50.degree. to 60.degree. C.

Abstract: A mixture controller for adjusting an output value, which is outputted by a PI two-point controller, to control the air/fuel ratio of a mixture supplied to an internal combustion engine to a pregiven value. The engine produces an exhaust-gas flow during operation and has an oxygen probe mounted in the exhaust-gas flow. The mixture controller continuously detects the signal of the oxygen probe to obtain sequential measurement values of the signal. A check is made as to whether a currently detected measurement value of the signal has crossed over a threshold value in the lean or rich direction compared to the previously detected measurement value of the signal. The output value is changed when a crossover of the signal in the lean direction is present by shifting the output value with a large step via a P-jump in the rich direction and starting an integration of the output value in the rich direction from a previous lean direction.

Abstract: A control system is described for metering the fuel in an internal combustion engine. On the basis of the operating state of the internal combustion engine and a mixture correction signal for correcting the deviation of the air/fuel ratio from a desired value, a basic injection quantity signal is generated. A transition compensation signal is also generated while taking into account an adaptive correction factor. The adaptive correction factor is generated by comparing the mixture correction signal with a reference. The transition compensation signal is logically combined with the basic injection quantity signal to form a signal indicative of the quantity of fuel to be injected. In a second exemplary embodiment, the adaptive correction factor is determined by comparing the output signal of an exhaust gas sensor with a reference.

Abstract: A method, including an amplitude evaluation of control oscillations of the oxygen content of the exhaust gas of an internal combustion engine in front of and behind a catalytic converter, for judging the operating condition of the converter in order to determine whether the performance of the catalytic converter has deteriorated past a predetermined point. As soon as this condition is detected using the amplitude evaluation, switching is effected to the frequency evaluation for judging the functioning of the catalytic converter.

Abstract: A control system and method for an internal-combustion engine with which the torque output of the internal-combustion engine can be reduced by suppressing the injection of fuel in individual cylinders in accordance with specifiable suppression patterns or by shifting the ignition firing point or the ignition angle. The suppression pattern is selected in dependence upon the desired torque reduction. The suppression of cylinders is allowed, however, only when in the case of the selected suppression pattern the number of cylinders to be suppressed per working cycle lies above a threshold value. The threshold value is selected in dependence upon the operating state of the internal-combustion engine, in particular on at least one of the following operating parameters: temperature of the internal-combustion engine, exhaust gas temperature, catalytic-converter temperature, load, rotational frequency, and a variable indicating whether a warm-up function of the internal-combustion engine has been activated.

Abstract: The invention is directed to a method for reducing the exhaust-gas emissions of an internal combustion engine which is equipped with a lambda control and a catalytic converter and for which the metering of fuel can be interrupted in dependence upon operating parameters. The method is characterized in that the engine at first is operated with a rich fuel/air mixture during transition from operation without fuel metering to operation with fuel metering. The oxygen deficiency associated therewith compensates the oxygen excess which is stored in the catalytic converter when the metering of fuel is interrupted. An operating state wherein oxygen is loaded therefore occurs quickly after a fuel cutoff. This operating state also defines an optimum at steady state and this is advantageous especially for the conversion of nitrogen oxide.

Abstract: The invention is directed to a method for determining the storage capacity of a catalytic converter of an internal combustion engine with the aid of a first signal from an oxygen-indicating first probe mounted forward of the catalytic converter and a second signal from an oxygen-indicating second probe mounted rearward of the catalytic converter. The first and second signals show the change from rich to lean and vice versa and the method includes the steps of: determining the storage capacity as a quantity proportional to the time-dependent integral of an integration variable; starting the integration at a time point at which said first signal changes from rich to lean or vice versa; and, ending the integration after a time interval. The method does not need a special test operation of the engine to determine the storage capacity of the catalytic converter.

Abstract: The invention is directed to a method and an arrangement for making an on-board diagnosis of a catalytic converter. For this purpose, the lambda value of the mixture is shifted in a targeted manner and the jump reaction of a signal of a lambda probe arranged rearward of the catalytic converter is utilized in order to detect the amount of mean-value shift for which the successively reduced oxygen-deficiency input quantities or excess input quantities in the catalytic converter drop below the oxygen-storage capability thereof.

Abstract: The invention is directed to a method and an arrangement for monitoring deterioration of lambda probes in the context of a two-probe control. The signal of the lambda probe forward of the converter functions to control the lambda controller and the signal of the lambda probe rearward of the converter influences the lambda controller via an actuating variable and the degree to which the controller is influenced operates for monitoring of the probe forward of the converter. With this method and arrangement, the quality and deterioration of the lambda probe forward of the converter are advantageously detected and, if required, an alarm signal is generated.

Abstract: The invention is directed to a method of determining the performance loss of a catalyzer by using a deterioration variable indicative of this performance loss. The catalyzer is affected by operating conditions and is mounted in the exhaust gas flow of an internal combustion engine having a lambda controller operated to provide a two-level response. The method includes the steps of: obtaining a measurement signal from a lambda probe mounted forward of the catalyzer and a test signal from a lambda probe mounted rearward of the catalyzer; forming a relationship between the measurement and the test signals; measuring values of operating variables which affect oxygen storage processes in the catalyzer; and, correcting the deterioration variable based on the values of the operating variables thereby reducing the influence of the operating conditions on the deterioration variable.

Abstract: The invention is directed to a connecting circuit for a potential-free lambda probe having a ground line and a signal line and having an offset voltage source which is connected to the ground line. This offset voltage source raises the potential of the ground line to a pregiven value relative to ground. A ground short is directly detectable in the connecting circuit of the invention in that the potential measured at the signal line drops below the offset voltage. In this way, it is no longer required as in conventional circuits to check for a ground short by enriching the mixture of an engine and to monitor the exhaust gas with the lambda probe.

Abstract: The invention is directed to a method for determining the particular current value of at least one control parameter for a lambda control of an internal combustion engine which provides a shift to make the fuel mixture lean or a shift to make the fuel mixture rich in dependence upon the operating state of the controlled engine. The method includes the steps of: determining a base value for the control parameter in dependence upon the current value of at least one pregiven operating variable as the current value applies for a control with a minimal discharge of toxic gas during steady-state operation of the engine; and, modifying the base value with a transition variable having a value decaying as a function of time when changes in the operating state of the engine occur.