Abstract: A method for operating a fuel tank arrangement for a motor vehicle. The fuel tank arrangement has a fuel tank, a hydrocarbon filter and a pump. The fuel tank is fluidically connected via a tank shut-off valve to the hydrocarbon filter and the hydrocarbon filter is fluidically connected, on the one hand, via the pump to an external environment of the fuel tank arrangement and, on the other hand, via a purge valve to an intake tract of an internal combustion engine. A first leakage test mode is carried out when the pressure in the fuel tank is greater than a pressure threshold value, in which a shut-off valve arranged in terms of flow between the pump and the external environment is closed and the tank shut-off valve is opened.

Abstract: Disclosed is a method for controlling depressurization in a fuel tank of a motor vehicle, including: the initial controlled opening of the isolation valve in order to lower the pressure inside the tank; determination of a blockage condition in the roll over valve on the basis of at least one item of information relating to the pressure gradient in the tank following the initial opening of the isolation valve; and, if the roll over valve blockage condition is met, the controlled closing of the isolation valve, followed by its controlled re-opening in order to continue lowering the pressure in the tank.

Abstract: Disclosed is a method for controlling the pressure inside a fuel tank of a motor vehicle, the motor vehicle including a fuel vapor vent circuit connecting the tank to a fuel vapor canister, the vent circuit including an isolation valve for isolating the tank and a rollover valve. The pressure control method includes steps of: determining an activation duration required for the isolation valve to transition from a closed state to a fully open state, referred to as the “full opening duration”, when a predefined rollover valve closure risk criterion is satisfied: controlling the isolation valve in repeated activations of respective durations that are shorter than the full opening duration.

Abstract: Disclosed is a method for controlling depressurization in a fuel tank of a motor vehicle, including: the initial controlled opening of the isolation valve in order to lower the pressure inside the tank; determination of a blockage condition in the roll over valve on the basis of at least one item of information relating to the pressure gradient in the tank following the initial opening of the isolation valve; and, if the roll over valve blockage condition is met, the controlled closing of the isolation valve, followed by its controlled re-opening in order to continue lowering the pressure in the tank.

Abstract: Disclosed is a method for controlling the pressure inside a fuel tank of a motor vehicle, the motor vehicle including a fuel vapor vent circuit connecting the tank to a fuel vapor canister, the vent circuit including an isolation valve for isolating the tank and a rollover valve. The pressure control method includes steps of: determining an activation duration required for the isolation valve to transition from a closed state to a fully open state, referred to as the “full opening duration”, when a predefined rollover valve closure risk criterion is satisfied: controlling the isolation valve in repeated activations of respective durations that are shorter than the full opening duration.

Abstract: The invention relates to a method for regulating a fuel tank venting valve of a motor vehicle during leak testing of a fuel tank venting system where the fuel tank venting valve is arranged in a recovery line that connects a retention vessel to catch fuel vapors from a fuel tank to an inlet manifold of an operating internal combustion engine, comprising sealing the tank venting system from the atmosphere outside the motor vehicle, opening the fuel tank venting valve to expose the fuel tank and the tank venting system to a relative negative pressure present in the inlet manifold of the operating internal combustion engine and regulating the degree of opening of the tank venting valve based upon the external pressure, pA.

Abstract: In a combustion engine, combustion chamber-specific deviations can be equalized by associating a specific adjustable air-fuel ratio with the individual combustion chambers. When changing from full engine operation to partial engine operation, the associated air-fuel ratios do not always remain optimal. A new air-fuel ratio, which is adjusted immediately when changing from full engine operation to partial engine operation, is then associated with the combustion chambers of a subgroup of combustion chambers to which an air-fuel mixture is applied in partial engine operation. The new individual air-fuel ratios can be easily computed, in particular, from the individual air-fuel ratios associated with full engine operation.

Abstract: The invention relates to a method and a device for testing the tightness of a fuel tank of an internal combustion engine, in particular of a vehicle, with a pressure switch which communicates with the interior of the fuel tank, and a diagnosis means for testing the serviceability of the pressure switch by evaluating the switching status of the pressure switch. So that diagnosis of the pressure switch is possible even with the internal combustion engine shut off or the vehicle turned off and for internal combustion engines with exhaust gas turbochargers, it is proposed, according to the invention, that the diagnosis means test the opening behavior of the pressure switch when the temperature rises.

Abstract: The invention relates to a method for checking the function of a tank venting valve between the intake manifold of an internal combustion engine and a fuel tank or a fuel vapor reservoir in which the tank venting valve in operation of the internal combustion engine is opened several times and is closed again after a short opening time and in which during repeated opening and closing the time characteristic of a quantity which is dependent on the opening state of the tank venting valve is recorded. In order to enable a reliable function check of the tank venting valve even in the case of very small and/or time-shifted amplitudes of the quantity to be monitored, it is proposed, according to the invention, that the first derivative of the time characteristic of the quantity be evaluated.

Abstract: The switched state of a pressure switch in a tank ventilation system of a motor vehicle is used for testing the function of the tank ventilation system, the pressure switch being in a low-pressure position if the pressure in the tank ventilation system is lower than a predefined pressure limit while being in a high-pressure position if that is not the case. A defective pressure switch can result in wrong assessments. Disclosed is a method for testing the function of the pressure switch, the method encompassing the following steps: a switched state of the pressure switch is detected; a measure is carried out that increases the pressure in the tank ventilation system above the pressure limit if the pressure switch is in the low-pressure position; a defect of the pressure switch is identified if the pressure switch remains in the low-pressure position after carrying out the measure.

Abstract: In a method for verifying the tightness of a tank bleeding system with a tank bleeding valve, a stop valve for air-tightly closing the tank bleeding system relative to an atmosphere prevailing outside the motor vehicle, and a bistable pressure switch whose switched condition indicates whether a predefined switching pressure is exceeded or not reached in the tank bleeding system, in order to be able to determine the tightness of the tank bleeding system without using a pressure sensor, the following steps are carried out: waiting until the vehicle speed drops below a certain threshold; opening the tank bleeding valve; closing the tank bleeding valve when a negative pressure has been attained which lies below the switching pressure; measuring the duration from the time an initial pressure lies below the switching pressure until the moment the switching pressure is exceeded again; and assessing the tightness is assessed based on the measured duration.

Abstract: A robust method, an accordingly designed control device, and an internal combustion engine, enables the proper performance of a tank ventilation device during the operation of the internal combustion engine. For this purpose, the position of a pressure switch of the tank ventilation device is detected, which indicates the pressure present in the tank ventilation device, a controllable tank ventilation valve, which is disposed in a connecting line between a fuel vapor accumulator and an intake pipe of the internal combustion engine, is opened at least partially during the operation of the internal combustion engine, the position of the pressure switch is again detected after opening of the tank ventilation valve, the proper performance of the tank ventilation device; is analyzed based on a comparison of the position of the pressure switch before opening the tank ventilation valve to the position of the pressure switch after opening the tank ventilation valve.

Abstract: The invention relates to a method for checking the function of a tank venting valve between the intake manifold of an internal combustion engine and a fuel tank or a fuel vapor reservoir in which the tank venting valve in operation of the internal combustion engine is opened several times and is closed again after a short opening time and in which during repeated opening and closing the time characteristic of a quantity which is dependent on the opening state of the tank venting valve is recorded. In order to enable a reliable function check of the tank venting valve even in the case of very small and/or time-shifted amplitudes of the quantity to be monitored, it is proposed, according to the invention, that the first derivative of the time characteristic of the quantity be evaluated.

Abstract: A robust method, an accordingly designed control device, and an internal combustion engine, enables the proper performance of a tank ventilation device during the operation of the internal combustion engine. For this purpose, the position of a pressure switch of the tank ventilation device is detected, which indicates the pressure present in the tank ventilation device, a controllable tank ventilation valve, which is disposed in a connecting line between a fuel vapor accumulator and an intake pipe of the internal combustion engine, is opened at least partially during the operation of the internal combustion engine, the position of the pressure switch is again detected after opening of the tank ventilation valve, the proper performance of the tank ventilation device; is analyzed based on a comparison of the position of the pressure switch before opening the tank ventilation valve to the position of the pressure switch after opening the tank ventilation valve.

Abstract: The invention relates to a method and a device for testing the tightness of a fuel tank of an internal combustion engine, in particular of a vehicle, with a pressure switch which communicates with the interior of the fuel tank, and a diagnosis means for testing the serviceability of the pressure switch by evaluating the switching status of the pressure switch. So that diagnosis of the pressure switch is possible even with the internal combustion engine shut off or the vehicle turned off and for internal combustion engines with exhaust gas turbochargers, it is proposed, according to the invention, that the diagnosis means test the opening behavior of the pressure switch when the temperature rises.

Abstract: A tank ventilating valve is disposed in a regeneration pipe which connects a storage container collecting fuel gas of a fuel tank to an intake pipe of the internal combustion engine. The tank ventilation system is air tightly sealed towards the atmosphere prevailing outside the motor vehicle while the tank ventilating valve is opened to create a negative pressure in the tank ventilation system. The method has the following steps: determining the fuel gas charge of the storage container; determining the volume flow rate through the tank ventilating valve; calculating an intermediate value from the product of the load and the volume flow rate; determining a tank pressure difference between the pressure prevailing in the fuel tank and the atmospheric pressure; and determining the additive corrective value by adjusting the intermediate value to the amount of the tank pressure difference.

Abstract: The switched state of a pressure switch in a tank ventilation system of a motor vehicle is used for testing the function of the tank ventilation system, the pressure switch being in a low-pressure position if the pressure in the tank ventilation system is lower than a predefined pressure limit while being in a high-pressure position if that is not the case. A defective pressure switch can result in wrong assessments. Disclosed is a method for testing the function of the pressure switch, the method encompassing the following steps: a switched state of the pressure switch is detected; a measure is carried out that increases the pressure in the tank ventilation system above the pressure limit if the pressure switch is in the low-pressure position; a defect of the pressure switch is identified if the pressure switch remains in the low-pressure position after carrying out the measure.

Abstract: In a method for verifying the tightness of a tank bleeding system with a tank bleeding valve, a stop valve for air-tightly closing the tank bleeding system relative to an atmosphere prevailing outside the motor vehicle, and a bistable pressure switch whose switched condition indicates whether a predefined switching pressure is exceeded or not reached in the tank bleeding system, in order to be able to determine the tightness of the tank bleeding system without using a pressure sensor, the following steps are carried out: waiting until the vehicle speed drops below a certain threshold; opening the tank bleeding valve; closing the tank bleeding valve when a negative pressure has been attained which lies below the switching pressure; measuring the duration from the time an initial pressure lies below the switching pressure until the moment the switching pressure is exceeded again; and assessing the tightness is assessed based on the measured duration.

Abstract: The invention relates to a method for functionally testing a filling level sensor which measures the filling level of a liquid in a tank, in which method a change in filling level that is measured by the filling level sensor is compared with a calculated change in filling level. According to the invention, the calculated change in filling level is determined from a measured change in temperature of the liquid.

Abstract: A tank ventilating valve is disposed in a regeneration pipe which connects a storage container collecting fuel gas of a fuel tank to an intake pipe of the internal combustion engine. The tank ventilation system is air tightly sealed towards the atmosphere prevailing outside the motor vehicle while the tank ventilating valve is opened to create a negative pressure in the tank ventilation system. The method has the following steps: determining the fuel gas charge of the storage container; determining the volume flow rate through the tank ventilating valve; calculating an intermediate value from the product of the load and the volume flow rate; determining a tank pressure difference between the pressure prevailing in the fuel tank and the atmospheric pressure; and determining the additive corrective value by adjusting the intermediate value to the amount of the tank pressure difference.