Abstract: Method for diagnosing a fan, in particular in a cooling circuit of an internal combustion engine, a current driving the fan being ascertained. The fan is triggered by a defined trigger signal, and depending on the ascertained current, a diagnosis of whether the fan is defective is performed.

Abstract: In a method for diagnosing a faulty thermostat in a coolant circuit, in particular for an internal combustion engine, having a fan, the faulty thermostat is detected as a function of a measured temperature and a setpoint temperature, the fan being turned on at least temporarily during the diagnosis.

Abstract: Method for diagnosing a fan, in particular in a cooling circuit of an internal combustion engine, a current driving the fan being ascertained. The fan is triggered by a defined trigger signal, and depending on the ascertained current, a diagnosis of whether the fan is defective is performed.

Abstract: A method for operating a tank leakage diagnosis device, especially of a motor vehicle, volatile fuel (to be degassed) being temporarily stored using an adsorption filter of known absorption capacity or absorption characteristics, and the adsorption filter being regenerated from time to time by purging, using fresh air, to avoid faulty measurements in the tank leakage diagnosis, in particular at elevated fuel degassing. It is provided that the adsorption filter be purged, and, in this context, the volatile fuel removed from the adsorption filter over a predefined time span be integrated, and from that, the loading of the adsorption filter with the volatile fuel, changing during the time span, is ascertained, from the absorption capacity and the absorption characteristics of the adsorption filter, as well as the integrated fuel quantity or the changing loading.

Abstract: In the method of monitoring a cooling fluid circuit of an internal combustion engine with setting a first error signal if a deviation of an actual value of a temperature from a desired value of the temperature exceeds a predetermined amount, a second error signal is set, which indicates a possible lack of antifreeze if a starting temperature is below the freezing point of water, a first error signal was present, the first error signal is no longer present after a predetermined time which is a function of the engine starting temperature and a build-in energy balance exceeds a threshold which is a function of the engine starting temperature.

Abstract: In a prior art method proposed for determining the outgassing of fuel, the outgassing at the ambient pressure is determined, and it is not taken into consideration that with the tank leakage diagnosis, a negative pressure exists inthe fuel tank. Since with negative pressure, more fuel gases out than with ambient pressure, too small of an outgassing is determined. With the tank leakage diagnosis, the fuel tank is evacuated at a diagnostic pressure and subsequently, a pressure increase is measured. From the trend of the pressure increase over the time, a leak is closed. Since the outgassing also affects a pressure increase, the measured total pressure increase must be corrected to the outgassing pressure increase. Since with the proposed method, the outgassing pressure increase is determined to be too small, frequently false reports can occur. The method of the present invention proposes to determine the outgassing at the same pressure that prevails with the tank leakage diagnosis in the fuel tank (1).

Abstract: In a method and a device for leak testing of a vessel, e.g., a tank venting system of a motor vehicle, a leak-tightness measurement is performed by introducing a positive pressure or partial vacuum and detecting the variation over time of a positive pressure or partial vacuum in the vessel, and a reference measurement is performed using a reference leak. A conclusion is drawn as to the presence of a leak in the vessel by comparing the results of the leak-tightness measurement and the reference measurement. To avoid faulty diagnoses, the positive pressure or partial vacuum during the leak-tightness measurement and the reference measurement is detected by using a single pressure measuring device.

Abstract: A method for operating a tank leakage diagnosis device, especially of a motor vehicle, volatile fuel (to be degassed) being temporarily stored using an adsorption filter of known absorption capacity or absorption characteristics, and the adsorption filter being regenerated from time to time by purging, using fresh air, to avoid faulty measurements in the tank leakage diagnosis, in particular at elevated fuel degassing. It is provided that the adsorption filter be purged, and, in this context, the volatile fuel removed from the adsorption filter over a predefined time span be integrated, and from that, the loading of the adsorption filter with the volatile fuel, changing during the time span, is ascertained, from the absorption capacity and the absorption characteristics of the adsorption filter, as well as the integrated fuel quantity or the changing loading.

Abstract: In a prior art method proposed for determining the outgassing of fuel, the outgassing at the ambient pressure is determined, and it is not taken into consideration that with the tank leakage diagnosis, a negative pressure exists in the fuel tank. Since with negative pressure, more fuel gases out than with ambient pressure, too small of an outgassing is determined. With the tank leakage diagnosis, the fuel tank is evacuated at a diagnostic pressure and subsequently, a pressure increase is measured. From the trend of the pressure increase over the time, a leak is closed. Since the outgassing also affects a pressure increase, the measured total pressure increase must be corrected to the outgassing pressure increase. Since with the proposed method, the outgassing pressure increase is determined to be too small, frequently false reports can occur. The method of the present invention proposes to determine the outgassing at the same pressure that prevails with the tank leakage diagnosis in the fuel tank (1).

Abstract: A method for detecting errors in a motor vehicle engine cooling system is proposed according to the invention, in which an algorithm is used to not only detect an error in the cooling system, but to also determine whether the thermostat valve or the temperature sensor are defective. Differentiated error detection is achieved in that a second temperature model band is calculated for the case in which the thermostat remains in the opened state. A first temperature model band is calculated for the case in which the cooling system is in order. By comparing the course of the curve for the measured actual temperature with the two temperature model bands, a selective diagnosis can be carried out and determine whether the temperature sensor or the thermostat valve is defective. No additional hardware expenditures are required.

Abstract: The invention is based on a method for monitoring a cooling fluid circuit (16) of an internal combustion engine (10), in which an electronic control unit (42) compares a measured actual value of a temperature of the engine (10) to a desired value of the temperature, which is determined from a stored model that depends on the energy throughput of the engine (10), and the control unit (42) sets a first error signal if the deviation of the actual value of the temperature from the desired value of the temperature exceeds a predetermined amount.

Abstract: In a method and a device for leak testing of a vessel, e.g., a tank venting system of a motor vehicle, a leak-tightness measurement is performed by introducing a positive pressure or partial vacuum and detecting the variation over time of a positive pressure or partial vacuum in the vessel, and a reference measurement is performed using a reference leak. A conclusion is drawn as to the presence of a leak in the vessel by comparing the results of the leak-tightness measurement and the reference measurement. To avoid faulty diagnoses, the positive pressure or partial vacuum during the leak-tightness measurement and the reference measurement is detected by using a single pressure measuring device.

Abstract: A method for detecting errors in a motor vehicle engine cooling system is proposed according to the invention, in which an algorithm is used to not only detect an error in the cooling system, but to also determine whether the thermostat valve or the temperature sensor are defective. Differentiated error detection is achieved in that a second temperature model band is calculated for the case in which the thermostat remains in the opened state. A first temperature model band is calculated for the case in which the cooling system is in order. By comparing the course of the curve for the measured actual temperature with the two temperature model bands, a selective diagnosis can be carried out and determine whether the temperature sensor or the thermostat valve is defective. No additional hardware expenditures are required.

Abstract: The invention relates to a method for detecting combustion misfires in a multi-cylinder internal combustion engine. Combustion misfires are detected from data for the rough running of individual cylinders via a comparison with threshold values at operating points stored in a characteristic field. These data are determined within the engine. The combustion misfire detection is suppressed below an rpm-dependent zero-load characteristic line. The zero-load characteristic line is continuously adapted to the actually present lowest load at corresponding rpm values during vehicle operation.

Abstract: A tank-venting system includes an active charcoal filter (20), which is connected to a tank (10). An intake manifold (40) of an internal combustion engine is connected to a tank-venting valve (30). The active charcoal filter (20) stores fuel vaporized in the tank (10). When the tank-venting valve (30) is driven open by the control unit (60), air from the ambient is drawn by suction through the active charcoal filter (20) and the fuel stored therein is released to the inducted air. A pump (50) is provided for checking the tightness of the tank-venting system and is connected to the control unit (60). A switchover valve (70) is connected downstream of the pump (50). A reference leak (81) is arranged in parallel to the switchover valve (70). A throughflow sensor (90) and a temperature sensor (91) are connected forward of the pump (50) which detect the scavenging air quantity, which is used to scavenge the active charcoal filter (20), as well as the intake air temperature.

Abstract: A tank-venting system includes an active charcoal filter (20), which is connected to a tank (10). An intake manifold (40) of an internal combustion engine is connected to a tank-venting valve (30). The active charcoal filter (20) stores fuel vaporized in the tank (10). When the tank-venting valve (30) is driven open by the control unit (60), air from the ambient is drawn by suction through the active charcoal filter (20) and the fuel stored therein is released to the inducted air. A pump (50) is provided for checking the tightness of the tank-venting system and is connected to the control unit (60). A switchover valve (70) is connected downstream of the pump (50). A reference leak (81) is arranged in parallel to the switchover valve (70). A throughflow sensor (90) and a temperature sensor (91) are connected forward of the pump (50) which detect the scavenging air quantity, which is used to scavenge the active charcoal filter (20), as well as the intake air temperature.

Abstract: The invention relates to a method for detecting combustion misfires in a multi-cylinder internal combustion engine. Combustion misfires are detected from data for the rough running of individual cylinders via a comparison with threshold values at operating points stored in a characteristic field. These data are determined within the engine. The combustion misfire detection is suppressed below an rpm-dependent zero-load characteristic line. The zero-load characteristic line is continuously adapted to the actually present lowest load at corresponding rpm values during vehicle operation.