Abstract: The invention relates to a method to determine the HC-conversion efficiency of a catalyst, which is situated in the exhaust gas flow path of an internal combustion engine and which is configured to convert hydrocarbons, by means of an oxygen-sensitive sensor that is installed downstream from the catalyst in the exhaust gas flow path and that exhibits a cross sensitivity to hydrocarbons. The method comprises: detecting a first signal of the downstream sensor in a first situation in which a first HC fraction is present in the exhaust gas upstream from the catalyst; detecting a second signal of the downstream sensor in a second situation in which a second HC fraction that is higher than the first HC fraction is present in the exhaust gas upstream from the catalyst; and determining the HC-conversion efficiency of the catalyst as a function of the first and second signals of the downstream sensor.

Abstract: The invention relates to a method to determine the HC-conversion efficiency of a catalyst, which is situated in the exhaust gas flow path of an internal combustion engine and which is configured to convert hydrocarbons, by means of an oxygen-sensitive sensor that is installed downstream from the catalyst in the exhaust gas flow path and that exhibits a cross sensitivity to hydrocarbons. The method comprises: detecting a first signal of the downstream sensor in a first situation in which a first HC fraction is present in the exhaust gas upstream from the catalyst; detecting a second signal of the downstream sensor in a second situation in which a second HC fraction that is higher than the first HC fraction is present in the exhaust gas upstream from the catalyst; and determining the HC-conversion efficiency of the catalyst as a function of the first and second signals of the downstream sensor.

Abstract: A method for diagnosing the dynamic characteristics of a lambda sensor, which is used at least intermittently for a cylinder-individual lambda closed-loop control, which provides for at least one actuating variable of the lambda closed-loop control to be detected and compared to a specifiable maximum threshold, and, if the maximum threshold is exceeded, the dynamic response of the lambda sensor is deemed insufficient with respect to the usability for the cylinder-individual lambda closed-loop control.

Abstract: A method for diagnosing the dynamic characteristics of a lambda sensor, which is used at least intermittently for a cylinder-individual lambda closed-loop control, which provides for at least one actuating variable of the lambda closed-loop control to be detected and compared to a specifiable maximum threshold, and, if the maximum threshold is exceeded, the dynamic response of the lambda sensor is deemed insufficient with respect to the usability for the cylinder-individual lambda closed-loop control.

Abstract: A process for detecting a state of a catalyst system installed in an exhaust gas channel of an internal combustion engine of a motor vehicle, through which catalyst system exhaust gas from the internal combustion engine flows so that the exhaust gas can be purified, the process including the steps of: detecting at least one operating parameter of the catalyst system over a predetermined time period, determining a total energy output of the internal combustion engine within the predetermined time period, and calculating a characteristic value (k) based on a ratio of the at least one operating parameter to the total energy output.

Abstract: An exhaust system of a multi-cylinder internal combustion engine includes at least one first gas sensor, which is sensitive for at least one component of the exhaust gas and is arranged in the exhaust system, for determining an air/fuel ratio supplied to the internal combustion engine. It also includes a regulating device for regulating the air/fuel ratio as a function of a signal supplied by the gas sensor and at least one first catalytic converter arranged in the exhaust system. At least one first catalytic converter is arranged in a position of the exhaust system close to the internal combustion engine so that it is upstream from the at least one first gas sensor in the direction of flow of an exhaust gas of the internal combustion engine, and the regulation device includes a regulator which receives the signal of the first gas sensor as input, and in which an algorithm for cylinder-selective determination and regulation of the air/fuel ratio is stored.

Abstract: An exhaust system of a multi-cylinder internal combustion engine includes at least one first gas sensor, which is sensitive for at least one component of the exhaust gas and is arranged in the exhaust system, for determining an air/fuel ratio supplied to the internal combustion engine. It also includes a regulating device for regulating the air/fuel ratio as a function of a signal supplied by the gas sensor and at least one first catalytic converter arranged in the exhaust system. At least one first catalytic converter is arranged in a position of the exhaust system close to the internal combustion engine so that it is upstream from the at least one first gas sensor in the direction of flow of an exhaust gas of the internal combustion engine, and the regulation device includes a regulator which receives the signal of the first gas sensor as input, and in which an algorithm for cylinder-selective determination and regulation of the air/fuel ratio is stored.

Abstract: A circuit arrangement measures an ion current generated in the combustion chamber of an internal combustion engine during an iron current flow phase following an ignition phase. A voltage drop across a feedback resistor (R.sub.1) connected in parallel to an inverting amplifier is measured since the voltage drop is proportional to the ion current resistance. The amplifier is connected with its inverting input to a low voltage end of a secondary winding of an ignition transformer or coil. The high voltage end of the secondary winding is connected through a spark gap of a spark plug to ground, whereby the spark plug functions as an ion current sensor during the ion current flow phase. Negative voltage peaks flowing during an ignition phase and the ignition current flowing during the ignition phase are diverted through respective first and second circuit branches. The first branch has a first semiconductor diode (D.sub.

Abstract: An ion current in the combustion chamber of an internal combustion engine is measured by using the spark plug as an ion current sensor. The ignition circuit arrangement has an ignition coil or transformer with a primary winding forming a primary circuit and a secondary winding forming a secondary circuit in which the spark plug is connected. A measuring voltage is applied to the secondary circuit by circuit components forming a measuring circuit for measuring the ion current. The measuring circuit provides a measuring voltage at a value that is lower than the battery voltage of the ignition system or corresponds to the battery voltage at most. A rectifying element is connected to the secondary circuit which feeds the secondary or ignition current into the battery circuit of the ignition system while an ion current caused to flow by the measuring voltage applied to the secondary circuit is measured between sparking times when no ignition current is flowing.

Abstract: A film sensor element is used to determine the mass of a flowing fluid, in particular an air mass flow in the intake tube of an internal combustion engine. Such a sensor is part of a measurement bridge and operates on the hot-wire anemometer principle, designed as a constant-resistance regulator connected to an operational amplifier. To reduce the response time, two separate resistance tracks of a film sensor element are structured in such a way that they are situated perpendicular to the direction of flow (S) with one track (6) along the leading edge and the other track (7) along the trailing edge. The tracks (6, 7) are electrically connected in parallel, such that the current can be divided according to the two resistance values as a current divider.

Abstract: An electronic ignition system for an internal combustion engine is so controlled that an ignition current or secondary current caused by an ignition spark at the respective spark plug in the secondary coil of an ignition transformer is evaluated for initiating, if necessary, follow-up charges of the primary coil to thereby generate further ignition impulses. The initial loading or charging impulse is provided by a respective control circuit. The total sparking time at the respective spark plug thus corresponds to a sequence of individual impulses, each of which causes an ignition spark. The detection of the ignition current in the secondary coils is performed with an ignition current measuring circuit arrangement connected to the secondary coils. This measuring circuit (SC) generates a signal representing the secondary or ignition current represented as a voltage drop across a measuring resistor (R.sub.2).

Abstract: For determining the air mass flow in the intake pipe of an internal combustion engine by means of an electrical bridge, normally the current flowing through the current measurement resistor when balancing the bridge is evaluated as an indirect measure of the air mass flow. The primary measured quantity for the air mass flow is, however, the power converted at the air flow measurement resistor around which the air flows so that the indirect measurement always includes an error. To reduce this measurement error, the invention utilizes the evaluation of the sum of the voltage across the current measurement resistor and the voltage or a partial-voltage across the air flow measurement resistor as a measure of the air flow.

Abstract: For detecting the angle of rotation of a shaft, in particular of a gear shift shaft in a gear change box for a motor vehicle, a device is proposed in which a carrier arrangement carries a magnet and in its proximity magnetically sensitive sensors. A screening device, rigidly attached to the shaft, moves in the intermediate space between the magnet and the sensors. This screening device is made from a ferromagnetic material such that the magnetic field permeating the sensors is influenced in a manner whereby the sensors generate a signal that unambiguously identifies the position of the shaft.

Abstract: In an alternating current ignition system whose ignition output stage has an ignition coil, a resonant-circuit capacitor for generating a bipolar alternating current, a semiconductor switch for controlling the primary coil current and an energy recovery diode connected in parallel to the semiconductor switch, the current flowing through the diode serves as control signal for the semiconductor switch and triggers the switching-on of the semiconductor switch.