Abstract: An internal combustion engine (1), especially for a motor vehicle, is described, which has a catalytic converter (12) which can be loaded with and unloaded of nitrogen oxides. An NOx sensor (14) is provided with which NOx emissions can be measured downstream of the catalytic converter (12). The catalytic converter (12) can be only partially loaded by a control apparatus (18). An increased NOx emission can be generated forward of or in the catalytic converter (12) by the control apparatus (18). A conclusion can be drawn as to the operability of the catalytic converter (12) by the control apparatus (18) from NOx emissions measured downstream.

Abstract: An internal combustion engine (1), especially for a motor vehicle, is described, which has a catalytic converter (12) which can be loaded with and unloaded of nitrogen oxides. An NOx sensor (14) is provided with which NOx emissions can be measured downstream of the catalytic converter (12). The catalytic converter (12) can be only partially loaded by a control apparatus (18). An increased NOx emission can be generated forward of or in the catalytic converter (12) by the control apparatus (18). A conclusion can be drawn as to the operability of the catalytic converter (12) by the control apparatus (18) from NOx emissions measured downstream.

Abstract: The invention is directed to a control of an air/fuel ratio during operation of an internal combustion engine having a catalytic converter and an NOx sensor mounted behind the catalytic converter as seen in flow direction. The engine is operated alternately in a first phase with a mixture which is deficient in fuel compared to the stoichiometric mixture composition and, in a second phase, with a stoichiometric or rich mixture composition. The triggering of the change between the two phases is influenced by the signal of the NOx sensor.

Abstract: A method is presented for controlling the supply of reducing agent to a NOx-storage catalytic converter of an internal combustion engine, which is operated at least at times with a lean air/fuel mixture, with an exhaust-gas sensor mounted in flow direction rearward of the NOx-storage catalytic converter; wherein the supply of the reducing agent takes place repeatedly in time intervals separate from each other; and wherein the reducing agent quantity, which is supplied in each time interval, is reduced compared to that quantity which is supplied in a previous supply phase in which a reaction of the exhaust-gas sensor occurred.

Abstract: The invention is directed to a method for detecting a filling or tanking operation on a receptacle. The pressure is measured to obtain a trace of pressure as a function of time which is characteristic for a tanking operation. A conclusion that a tanking operation is present is made from the trace.

Abstract: The disclosure is directed to a method for improving the exhaust-gas quality, which is reduced by sulfur influence, in combustion processes with exhaust-gas catalytic converters. In the method, the oxygen storage capability of the catalytic converter is determined and is compared to a threshold value. When there is a drop below the threshold value, the exhaust-gas temperature is increased and/or an exhaust-gas composition, which acts in a reducing manner, is generated forward of the catalytic converter.

Abstract: The invention is directed to a method for checking an exhaust-gas catalytic converter for an internal combustion engine wherein the oxygen content of the exhaust gas is determined rearward of the catalytic converter and the mean oxygen content of the exhaust gas forward of the catalytic converter is changed in a direction which leads away from the oxygen content previously determined rearward of the catalytic converter. The resulting change of the oxygen fill level of the catalytic converter is determined which results from the change of the average oxygen content. This change is compared to a predetermined limit value. A fault announcement is not made when the predetermined limit value is exceeded before the oxygen content of the exhaust gas rearward of the catalytic converter changes. An arrangement for carrying out the method of the invention is also disclosed.

Abstract: The invention is directed to a method for checking the operability of a tank-venting system of a motor vehicle. The tank-venting system includes a tank, an adsorption filter and a tank-venting valve. The adsorption filter has a venting line and is connected to the tank via a connecting line. The tank-venting valve is connected to the adsorption filter via a valve line. In the method, a pressure source introduces a pressure into the tank-venting system which is an overpressure compared to atmospheric pressure and the pressure source has at least one operating variable. A first time-dependent trace of the one variable is provided and this trace is characteristic for a diagnostic trace undisturbed by a tanking operation. A second time-dependent trace of the one variable is detected during standstill of the vehicle and is compared to the first time-dependent trace. An output of a fault announcement is inhibited when the second time-dependent trace deviates from the first time-dependent trace by a pregiven value.

Abstract: The invention is directed to a method of avoiding an erroneous fault announcement when diagnosing a tank-venting system for a motor vehicle having an internal combustion engine. In the method a change in elevation is determined at which the motor vehicle is operated during the diagnosis and this change in elevation is considered in the determination of the diagnostic result.

Abstract: A device for diagnosis of a tank ventilation system of a vehicle, including a tank, an adsorption filter that communicates with the tank by way of a tank connection line and has a ventilation line, a tank ventilation valve that communicates with the adsorption filter by way of a valve line, and an on-board pressure source, by means of which the tank ventilation system can be acted upon with a pressure. A shut-off device is provided that only opens when the tank ventilation system is acted on with pressure by means of the on-board pressure source and closes when the tank ventilation system is acted on with pressure by means of a pressure source connected externally for the purpose of functionality testing.

Abstract: The invention is directed to a method for detecting a fill level of a tank system utilizing a pressure source, a bridge divider arrangement and a pressure measuring device. The pressure source is adapted to generate a change of pressure in the tank system. The pressure divider arrangement has a reference measuring unit which can be charged with pressure by the pressure source. The reference measuring unit further includes at least one flow resistor of a predetermined size in at least one reference flow branch. For measuring the tightness, the pressure measuring device simultaneously detects the difference of the pressure in the tank system and of the pressure in the reference measuring unit. In the method, the time-dependent trace of the difference pressure during at least one of a pressure build-up operation and a pressure decay operation is continuously detected. A conclusion is then drawn as to the fill level from the time-dependent trace.

Abstract: The invention is directed to a method for detecting a filling or tanking operation on a receptacle. The pressure is measured to obtain a trace of pressure as a function of time which is characteristic for a tanking operation. A conclusion that a tanking operation is present is made from the trace.

Abstract: A method of determining bad travel distances during traveling of a motor vehicle having a fuel tank, includes the steps of providing a differential pressure sensor at the fuel tank, determining by the differential pressure sensor a filling level of the fuel tank and producing a filling level pressure signal, determining by the differential pressure sensor a gas pressure inside the fuel tank and producing a gas pressure signal, and determining a bad travel distance by evaluating fluctuations in at least one of the pressure signals.

Abstract: A tank venting system for motor vehicles, having an internal combustion engine supplied from a fuel tank. A filter housing with an adsorption filter, and an air inlet and an air outlet that can be connected to a venting neck of the fuel tank. An air pump device for error diagnosis, which is integrated with a pump housing that has a pump inlet and a pump outlet. To attain a compact design of the tank venting system that is economical in terms of installation space, the pump housing is mounted with the pump outlet oriented coaxially to the air inlet on the filter housing and secured on the filter housing by means of spring-elastic fastening elements. The transition between the pump outlet and the air inlet is sealed off in airtight fashion.

Abstract: The invention is directed to a method and arrangement for checking the operability of a vessel. Pressure is introduced into the vessel utilizing a pressure source having operating variables which vary during operation of the pressure source. These operating variables are detected while the pressure is introduced into the vessel and a conclusion as to a presence of a leak in the vessel is drawn from the operating variables. By utilizing the operating variables, a statement as precise as possible is provided as to the presence of the leak with as little additional equipment as possible.

Abstract: A tank venting device for motor vehicles having an internal combustion engine supplied from a fuel tank. The device includes a filter housing, which is connectable to a venting stub of the fuel tank and includes an adsorption filter, whose air inlet is occupied by a shutoff valve and whose air outlet communicates with an intake tube of the engine, and an air feed pump and a diagnosis device. To improve the metering capability for the regeneration mixture aspirated from the filter to the intake tube of the engine, the air feed pump is disposed with a reversible feeding direction between the air outlet of the filter housing and the intake tube of the engine. The air feed pump is controlled in its feeding direction reversal via a multiposition control valve such that the filter housing is located on the intake side of the air feed pump for the duration of filter regeneration, and on the pressure side of the air feed pump for the duration of error diagnosis.

Abstract: The invention is directed to a method for checking the tightness of a tank system of an internal combustion engine having an intake pipe. The tank system includes: a fuel tank wherein fuel vapor forms, a regeneration valve connected to the intake pipe; an adsorption filter connected between the regeneration valve and the fuel tank; the regeneration valve being movable between a closed position and an open position wherein the fuel vapor is drawn by suction into the intake pipe; the adsorption filter having a venting line; and, a shutoff valve for the venting line and being movable between a first position wherein the venting line is closed off pressure tight and a second position wherein the venting line is open to the adsorption filter; and, a pump for generating a diagnostic overpressure in the tank system.

Abstract: A pump device for performing a leak diagnosis of a fuel vapor retention system. The pump device is provided for a fuel vapor retention system of an internal combustion engine, having a pump membrane driven by an electromagnet and a magnetic armature, which membrane defines a supply chamber that has valve devices, wherein a first valve can be connected to ambient air via a delivery line and can be connected via a second valve to a feed pipe that has an adsorption filter, and having a stop valve between the delivery line and the feed pipe, which valve is embodied so that it can be electromagnetically actuated. The pump device according to the invention is provided for a fuel vapor retention system of an internal combustion engine.

Abstract: The invention is directed to a method for detecting and documenting exhaust-gas relevant malfunctions of a vehicle having an internal combustion engine and a fuel tank utilizing on-board diagnosis. In the method, malfunctions are detected utilizing a sensor device and the malfunctions are evaluated in a circuit unit with the malfunctions including those malfunctions which are based on an empty tank. The fault announcements of the malfunctions are stored in a memory in dependence upon a pregiven number of drive cycles. A fill-level value indicative of the level of fuel in the fuel tank is determined and stored in the memory. Fault announcements of the malfunctions are outputted and stored in the memory in dependence upon the fill-level value thereby eliminating fault announcements of the malfunctions based on an empty tank.

Abstract: The invention is directed to a method for pneumatically checking the operability of a tank-venting system having a tank made of a material such as plastic. The tank-venting system includes an adsorption filter having a venting line with a closeable shutoff valve mounted in the venting line. The adsorption filter is connected to the tank via a tank connecting line and a tank-venting valve. In the method, the tank-venting system is first charged with a first overpressure or underpressure which exceeds, by a predetermined value, a second overpressure or underpressure corresponding to a diagnostic overpressure or diagnostic underpressure with the tank-venting valve and the shutoff valve being closed. The first overpressure or underpressure is then removed after a pregiven time span has elapsed and an overpressure or underpressure decay gradient measurement is made only after an essentially constant diagnostic overpressure or diagnostic underpressure adjusts in the tank-venting system.