Abstract: A Portable Maintenance Aid (PMA) having multiple applications for the electrical testing and data acquisition for various air/ground vehicle platforms is disclosed. The PMA includes an interface adapter that has a number of electrical testing interfaces and data collection ports in addition to a stray voltage detector. The portable testing aid also includes a user interface that transmits data to the interface adapter and a display that communicates the testing and maintenance information to the user. The portable testing aid also includes a communication system for transferring information between the user interface, the display, and the interface adapter. The PMA provides a preload tester/stray voltage tester that is sustainable, less replaceable and has capability of filling the test voids.

Abstract: Methods and systems are provided for performing a non-intrusive engine compression test. When compression testing is requested, a hybrid vehicle engine may be spun unfueled using energy from a battery driven electric motor. Changes in battery current over multiple engine cycles is used to infer cylinder compression parameters and assess cylinder compression degradation.

Abstract: A system for testing a number of electronic module assemblies (EMAs) that control one or more personal restraint systems. A programmed processor with a computer system transmits signals that instruct the EMAs to perform a diagnostic self-test. The results of the self-test are received by the computer system and stored in a computer readable memory. In one embodiment, the computer system is a cabin management computer system for use on an aircraft.

Abstract: Any one of ECUs that are operating detects a present power supply voltage repeatedly. When the voltage detected at the present time is changed from the voltage detected at the previous time, a difference is calculated as a variation value and the repeatedly calculated variation values are integrated to provide a voltage variation integrated value. When the variation of the power supply voltage of an ECU becomes great relatively due to a loose connection in a power supply line, the calculated voltage variation integrated value becomes greater than those of the other ECUs. In addition, when a defect arises in a common power supply source, the voltage variation integrated value increases in all the ECUs. Therefore, each integrated value of the variation values of the power supply voltage in each of the ECUs enables an anomaly diagnosis of an occurrence point of the defect.

Abstract: The present invention relates to a test apparatus based on DFDAU (Digital Flight Data Acquisition Unit), comprising: a simulation signal generation portion; and a test portion; wherein, the simulation signal generation portion comprises: an input interface, which receives test data; a simulation signal generation module, which generates simulation signal according to the test data; and an output interface, which is adaptive to be connected to one end of one or more signal transmission device to be tested and output the simulation signal; wherein, the test portion comprises: wiring extension apparatus, which is used to form a gating wiring apparatus and is adaptive to be connected to the other end of the one or more signal transmission devices to be tested, and receive the simulation signal passing through the one or more signal transmission devices to be tested; DFDAU, which is adaptive to receive simulation signal from the wiring extension device, and obtain the transmitted test data; a comparison module, wh

Abstract: [Problem] An object of the present invention is to provide a power state diagnosis method and a power state diagnosis apparatus that pass and increase not only a d-axis current but also a q-axis current to a current value that a steering behavior does not occur to perform a diagnosis in the vector control of a motor, and determine that a power supply degraded, that the power supply is normal and that the diagnosis is not completed without giving an uncomfortable feeling to a driver, detecting a timing that there is not a driver, and needing to comprise a plurality of actuators.

Abstract: A method for detecting a wear condition of a tire utilizes tread pattern elements included on the tire. The elements are adapted to generate first and second acoustic footprint noises (BEA1, BEA2), with one of the first and second acoustic footprint noises being characteristic of the wear condition of the tire. According to the method, a parent frequency spectrum, which is capable of forming a frequency spectrum of one of the first and second acoustic footprint noises, and a child frequency spectrum, which is capable of forming a frequency spectrum of the other of the first and second acoustic footprint noises, are selected from a frequency spectrum of an acoustic signal acquired from the tire. Two detection confidence indices are determined. If each detection confidence index meets a predetermined condition, a warning is emitted indicating that tire wear has been detected.

Abstract: A powertrain control module determines engine oil properties based on friction in an engine. The powertrain control module includes an engine combustion module that models engine torque based on engine speed and engine pumping losses due to intake and exhaust gasses. A transmission module models transmission torque applied to the engine based on transmission speed and gear. An accessory loads module models torque applied to the engine by accessory loads including at least one of a power steering pump, an air conditioning compressor, a water pump, and an alternator. An oil viscosity module determines engine oil viscosity based on a friction torque and predetermined engine data that coincides with reference oils. The friction torque is based on the engine torque, transmission torque, and accessory loads torque.

Abstract: A method and device for accessing maintenance functions of an aircraft from a mobile maintenance terminal. First, the situation of the aircraft is determined. Then, if this situation allows a mobile maintenance terminal to access a maintenance information system on the ground and the information system of the aircraft, a connection is established between the mobile maintenance terminal and the maintenance information system on the ground and at least one maintenance command intended for the information system of the aircraft is transmitted to the maintenance information system on the ground. If this situation allows the mobile maintenance terminal to access only the information system of the aircraft, a connection is established between the mobile maintenance terminal and the information system of the aircraft and at least one maintenance command is transmitted to the information system of the aircraft.

Abstract: A method and apparatus for managing a programmable control panel for a vehicle. A number of first level control functions is assigned to the programmable control panel for the vehicle. A number of second level control functions is assigned to the programmable control panel based on a health of programmable control panels in the vehicle.

Abstract: The invention relates to a method for diagnosing the operational state of a fuel supply system of an automobile internal combustion engine, said fuel being stored in a tank of the vehicle and having a variable alcohol content, wherein said method includes a step of diagnosing (S6) the operational state of the fuel supply system, a step of detecting the addition of alcohol into the tank (S2), a step of determining the alcohol content (S2bis) in the fuel, and a checking step (S4) in which the diagnosis step (S6) is triggered if the step of determining the alcohol content (S2bis) in the fuel is completed.

Abstract: Techniques for operating, testing, and generating a testing report for the electrical and air subsystems of a vehicular trailer, without the use of an associated truck tractor are disclosed. The system includes a portable testing unit with self-powered electrical and air subsystems which are interconnected to the corresponding subsystems of the vehicular trailer under test. The portable testing unit can be rolled about on a stand and functions as a mini-truck tractor, in the sense that it selectively provides electrical power and air to the VUT. The testing unit is controlled by a small, portable hand held radio frequency remote control that communicates test and data signals to a radio receiver in the portable testing unit. The system acquires testing data from both automatic and manual means from disparate sources. The system stores the testing data and automatically generates testing reports. The system manages the testing data and generated reports.

Abstract: Methods and systems are provided for estimating fuel volatility. During a vehicle-off condition following a refueling event, fuel volatility may be estimated. Based on estimated fuel volatility, fuel injection amount and leak test thresholds may be adjusted.

Abstract: A diagnostic system configured to test the performance of a vehicle component may include a processor configured to process test information from the vehicle component and control the vehicle component to be tested. The system may also include a memory configured to store the test information of the vehicle component and software that operates the vehicle component and a capacitive element configured to supply power to perform the testing of the vehicle component, wherein the memory and the capacitive element are in communication with the processor.

Abstract: A graphical user interface is provided that can be used on a diagnostic tool. The graphical user interface allows a technician to operate various functions of the diagnostic tool including searching for additional information on the Internet, receiving weather information that is relevant to certain diagnostic tests, and displaying in certain formats the retrieved vehicle data and when certain vehicles were last scanned or diagnosed.

Abstract: A graphical user interface is provided that can be used on a diagnostic tool. The graphical user interface allows a technician to operate various functions of the diagnostic tool including searching for additional information on the Internet, receiving weather information that is relevant to certain diagnostic tests, and displaying in certain formats the retrieved vehicle data and when certain vehicles were last scanned or diagnosed.

Abstract: An apparatus for use with a motor vehicle to simulate fuel loss to encourage early refueling to prevent stranding. The apparatus may cause stumbling and hesitation by interrupting various engine management systems to simulate low fuel in the tank by cutting either spark or fuel momentarily or applying the brakes.

Abstract: A system and method is presented for diagnosing problems in a sensor, a vehicle computer and a vehicle sensor wiring harness. The diagnostic system comprises a sensor simulator configured to be selectively coupled to the vehicle computer via a wiring harness during a diagnostic mode, and to eliminate and simulate a known good sensor to the vehicle computer by way of the vehicle sensor wiring harness directly connected therebetween. The system includes an external computer adapted to selectively couple the sensor simulator to the vehicle computer, and a user keypad and memory to receive and store user commands of a selected manufacturer's make, model, year of vehicle, and the function type of the selected sensor, and to enable the user to select or adjust a typical operational value comprising one or more of a voltage, current or resistance operational range values of the selected sensor.

Abstract: An off-board vehicle fuel containment tester that utilizes a vacuum/pressure pump to change the pressure in the vehicle's fuel handling and containment system. A microprocessor is programmed to control the vacuum/pressure pump system and through the reading produced by a pressure transducer will determine, by the pressure changes occurring in the containment system, if a leak is present and the size of the leak. Once a leak is determined to be present, a gas analyzer that can detect carbon monoxide and hydrocarbons is used to find the point of leakage in the vehicle containment system.

Abstract: A diagnostic system configured to test the performance of a vehicle component may include a processor configured to process test information from the vehicle component and control the vehicle component to be tested. The system may also include a memory configured to store the test information of the vehicle component and software that operates the vehicle component and a capacitive element configured to supply power to perform the testing of the vehicle component, wherein the memory and the capacitive element are in communication with the processor.

Abstract: Systems and vehicles for determining an operational status of at least one trailer brake are provided. A system for determining an operational status of at least one trailer brake includes machine readable instructions stored in one or more memory modules that, when executed by one or more processors, cause the system to command a trailer brake current output circuit to intermittently supply a diagnostic current to the at least one trailer brake during a trailer brake activation period, receive a sensed current signal from a trailer brake current sensing circuit in response to the command to supply the diagnostic current, and determine the operational status of the at least one trailer brake based on the sensed current signal.

Abstract: A method is provided for processing data in an influencing device, whereby the influencing device is connected to a vehicle control unit and to a data processing unit. The vehicle control unit and the influencing device are disposed in a motor vehicle or, for example, on a test bench in a laboratory. A first program runs in the vehicle control unit. Data are exchanged according to an XCP protocol and/or a CCP protocol between the data processing unit and the influencing device. The influencing device has a second execution unit, which executes predetermined data processing steps more rapidly than the first execution unit. The data exchanged by the XCP protocol or the CCP protocol are checked for a predetermined criterion and, based on the result of the check, the data are processed either in the first execution unit or in the second execution unit.

Abstract: A control device for a brake system of a rail vehicle, wherein the brake system includes a friction bracket device which is dependent on frictional engagement. The control device determines a braking effect applied during a braking process on the basis of a brake pressure or brake current and at least one further parameter. Also disclosed are a brake system having such a control device and a method for determining a braking effect.

Abstract: A method and a measurement system are specified for localizing at least one wheel on a motor vehicle. In this case the operating situation of the motor vehicle and the wheel load of the at least one wheel and/or a variable dependent on this is determined. Then the at least one measured value of the wheel load is compared with a value assigned to the operating situation. As an alternative or in addition, the comparison of at least one parameter dependent on at least two measured values can be undertaken with at least one of the parameters assigned to this operating situation. Finally the point on the motor vehicle at which the wheel is mounted is determined on the basis of the comparison results.

Abstract: Techniques for operating, testing, and generating a testing report for the electrical and air subsystems of a vehicular trailer, without the use of an associated truck tractor are disclosed. The system includes a portable testing unit with self-powered electrical and air subsystems which are interconnected to the corresponding subsystems of the vehicular trailer under test. The portable testing unit can be rolled about on a stand and functions as a mini-truck tractor, in the sense that it selectively provides electrical power and air to the VUT. The testing unit is controlled by a small, portable hand held radio frequency remote control that communicates test and data signals to a radio receiver in the portable testing unit. The system acquires testing data from both automatic and manual means from disparate sources. The system stores the testing data and automatically generates testing reports. The system manages the testing data and generated reports.

Abstract: A method of operating a motor vehicle having a drive aggregate, a transmission and a hydraulic system. The transmission has shift elements and, for each gear, only a portion of the elements are engaged while a remainder are disengaged. The hydraulic system has main pump driven by the drive aggregate and an auxiliary pump. The method tests the functionality of the auxiliary pump. The drive aggregate and the main pump are insufficiently driven such that the shift elements can not engage. The auxiliary pump is driven to provide required pressure such that all but one of the shift elements fully engages. The remaining shift element is then first engaged up to its engagement point and then either engaged beyond its engagement point or another unengaged shift element is engaged beyond its engagement point. The functionality of the auxiliary pump is determined based on changes in the drive aggregate's rotational speed.

Abstract: The invention described herein relates to aiding a Satellite Positioning System (SPS) receiver of a platform with a data interface to the platform data. The platform, for example, could be a vehicle, ship, aircraft, or a pedestrian. The SPS receiver would be used to track the location of the platform. The data interface would facilitate access by the SPS receiver to the data of the platform, and the SPS receiver in turn could provide SPS data (such as position, speed, and heading) to the platform. A further aspect of the invention includes hardware or software used by the data interface and the SPS receiver to provide, format, time-stamp, synchronize, and match platform data or SPS receiver data.

Abstract: A method of testing a braking device in a drivetrain of a vehicle which includes at least one tractive element coupled to a traction motor. The method includes: (a) applying the braking device to a tractive element of the vehicle; (b) using an electronic controller, causing the traction motor to apply a predetermined force to the tractive element; and (c) using the controller, monitoring the tractive element for movement while the force is being applied. A dynamic braking or “retarder” function may also be tested. A system for carrying out the method is provided.

Abstract: A vehicle system providing a temporary validation authorization request for one or more processors configured to transmit a signal from the vehicle system to a server once the one or more processors are installed in the vehicle. Once the server receives the installation signal, the processor may receive an in-vehicle authorization message from the server. The in-vehicle authorization message may be accepted by a user-input acceptance transmitted to the server. The system may determine temporary validation authorization if it is determined that the user accepted the in-vehicle authorization message within a predetermined amount of time following transmission of the signal to the server indicating that the processor was installed. Once authorized, the system may initialize to allow for assembly line testing. The temporary validation authorization initializes the vehicle system for temporary communication with the server while on a vehicle manufacturing assembly line for testing to ensure a quality product.

Abstract: The invention relates to a device and method for testing simultaneously and dynamically multiple dynamic systems of a track-based vehicle.

Abstract: Techniques for operating, testing, and generating a testing report for the electrical and air subsystems of a vehicular trailer, without the use of an associated truck tractor are disclosed. The system includes a portable testing unit with self-powered electrical and air subsystems which are interconnected to the corresponding subsystems of the vehicular trailer under test. The portable testing unit can be rolled about on a stand and functions as a mini-truck tractor, in the sense that it selectively provides electrical power and air to the VUT. The testing unit is controlled by a small, portable hand held radio frequency remote control that communicates test and data signals to a radio receiver in the portable testing unit. The system acquires testing data from both automatic and manual means from disparate sources. The system stores the testing data and automatically generates testing reports. The system manages the testing data and generated reports.

Abstract: An active air flap apparatus for a vehicle may include a drive flap positional sensor connected with a drive shaft connecting an actuator and a drive flap and detecting a rotational angle of the drive flap, a driven flap pivotally connected with the drive flap through a link mechanism, a driven flap positional sensor connected with a driven shaft pivotally connected with the link member and detecting a rotational angle of the driven flap, and a controller determining whether the drive flap positional sensor, the driven flap positional sensor, a motor of the actuator, and the link member may be defective by monitoring a feedback voltage value of the drive flap positional sensor, a feedback voltage value of the driven flap positional sensor, and a current applied to the motor of the actuator.

Abstract: Techniques for operating, testing, and generating a testing report for the electrical and air subsystems of a vehicular trailer, without the use of an associated truck tractor are disclosed. The system includes a portable testing unit with self-powered electrical and air subsystems which are interconnected to the corresponding subsystems of the vehicular trailer under test. The portable testing unit can be rolled about on a stand and functions as a mini-truck tractor, in the sense that it selectively provides electrical power and air to the VUT. The testing unit is controlled by a small, portable hand held radio frequency remote control that communicates test and data signals to a radio receiver in the portable testing unit. The system acquires testing data from both automatic and manual means from disparate sources. The system stores the testing data and automatically generates testing reports. The system manages the testing data and generated reports.

Abstract: Provided is a vehicle data providing apparatus supporting to easily generate vehicle internal communication data at the development stage of a product to perform a test. According to an aspect, there is provided a vehicle data providing apparatus including: a vehicle data analyzer configured to analyze a vehicle data file that is used in a vehicle, and to provide a reference data graph about reference data included in the vehicle data file; a vehicle data changing unit configured to receive a user input signal for changing the reference data, and to change related data associated with the reference data based on the reference data graph; and a test data file generator configured to generate a vehicle data file for test, including the changed reference data and the changed related data.

Abstract: A Portable Maintenance Aid (PMA) having multiple applications for the electrical testing and data acquisition for various air/ground vehicle platforms is disclosed. The PMA includes an interface adapter that has a number of electrical testing interfaces and data collection ports in addition to a stray voltage detector. The portable testing aid also includes a user interface that transmits data to the interface adapter and a display that communicates the testing and maintenance information to the user. The portable testing aid also includes a communication system for transferring information between the user interface, the display, and the interface adapter. The PMA provides a preload tester/stray voltage tester that is sustainable, less replaceable and has capability of filling the test voids.

Abstract: A diagnostic platform includes a processor, storage media and user interfaces, including a display screen, the processor being coupled to engine analyzer hardware and adapted to be coupled to a scanner for downloading data from vehicle on-board computers. The system stores libraries of information regarding vehicle identifications, drivability symptoms exhibited by vehicles, vehicle system and component tests and service codes which can be registered by the vehicle on-board computer. System software permits the user to input an identification of the vehicle under test and, in one mode of operation, displays a library of faults, such as symptoms or service codes, from which the user can select those exhibited by the vehicle, whereupon the system selects from the test library those tests pertinent to diagnosis of the causes of the selected faults and displays them in a hierarchically ranked order based on likelihood of successful diagnosis of the faults. The user can then select and initiate any displayed test.

Abstract: A monitoring method that includes calculating the autonomy of a lubrication system of an airplane engine and also providing for the diagnosis and prognosis of a plurality of problems and breakdowns of the engine and of its lubrication system by means of measurements taken by sensors arranged in the lubrication system. The method further comprises the step of calculating the status of the lubrication system at a given moment and calculating its evolution over time in order to determine the remaining lifetime before a breakdown.

Abstract: A portable measurement apparatus is provided for measuring the load required to depress a foot pedal and the change in angular position of the foot pedal. A load plate is connected through at least one load cell to a pedal plate that engages a foot pedal. A linear motion driver is adjustably retained on the measurement apparatus to accommodate different types of foot pedals. A rotary encoder with an extendable cable is used to measure scrub throughout the range of movement of the foot pedal.

Abstract: A warning system for vehicles contains a detecting device for capturing different change values of an internal resistance coefficient generating from a water quantity of an outlet tube of a water tank and different change values relative to a float voltage; a detection module used to determine the different change values of the internal resistance coefficient generating from the water quantity of the outlet tube of the water tank and captured by the detecting device and to determine the different change values relative to the float voltage, and then to compare the internal resistance coefficient and the float voltage with a predetermined standard coefficient, thus determining if the warning system is normal and amplifying an output signal to make sounds. Thereby the detection module, the detecting device, and a car housing form an electricity conducting circuit so that detection and alert are obtained automatically.

Abstract: In a machine-implemented method for obtaining data from a nonlinear dynamic real system during a test run, for instance an internal combustion engine, a drive-train or parts thereof, of a sequence of dynamic excitation signals for at least one measurement channel is generated according to a previously generated design of experiment for said test run and the system output of at least one output channel is measured.

Abstract: A number of landings of an aircraft tyre is counted according to a method that includes: measuring a physical quantity of air contained inside the tyre, the measuring taking place in a discontinuous mode; determining at least one indicator relating to the physical quantity; comparing the at least one indicator with a predetermined threshold associated with the tyre; and, if the at least one indicator is greater than the predetermined threshold associated with the tyre, incrementing the number of landings of the tyre.

Abstract: A vehicle cooling system includes: a channel allowing a liquid medium cooling a drive device of the vehicle to circulate; a flow rate detection unit detecting a flow rate of the liquid medium flowing in the channel; a temperature sensor detecting a temperature of the liquid medium; a pump provided on the channel for circulating the liquid medium; a rotational speed sensor detecting a rotational speed of the pump; and a control device controlling drive of the pump. The control device identifies a malfunctioning part of the cooling system based on the flow rate and the temperature of the liquid medium and the rotational speed of the pump. Thus, since abnormalities of the cooling mechanism can be detected with higher precision so that the abnormalities are distinguished from each other, it is a limited part that should be checked when repairs are made and the work efficiency is improved.

Abstract: A device for acquiring and recording data captured in an aircraft including a plurality of sources of data streams to be recorded, at least one source of dated values of recording parameters, and a recording mechanism recording data from the data streams and parameter values, on at least one non-volatile information medium. The recording mechanism is adapted to store, in separate files, the data of the various streams of data associated with the dated values of recording parameters.

Abstract: A vehicle control system which can ensure high reliability, real-time processing, and expandability with a simplified ECU configuration and a low cost by backing up an error through coordination in the entire system without increasing a degree of redundancy of individual controllers beyond the least necessary level. The vehicle control system comprises a sensor controller for taking in sensor signals indicating a status variable of a vehicle and an operation amount applied from a driver, a command controller for generating a control target value based on the sensor signals taken in by the sensor controller, and an actuator controller for receiving the control target value from the command controller and operating an actuator to control the vehicle, those three controller being interconnected via a network.

Abstract: A method is provided for performing an evaporative leak diagnostic for a vehicle. A valve in a diagnostic module is commanded to a vent position. The valve connects a fuel system to atmosphere. A pump in the diagnostic module is operated to measure a reference pressure across an orifice in the diagnostic module to provide a threshold. The valve is commanded to a test position. The pump is operated to place the fuel system in a low pressure state. A series of pressures in the fuel system is measured. A diagnostic code is provided after comparing the series of pressures to the threshold.

Abstract: A method for performing diagnostics of a structure subject to loads, in particular an aircraft structure, is implemented by an arrangement of sensors located at relevant points of the structure and corresponding neural networks. The method includes training the neural network in order to establish an associative relationship between the state of the structure in a subset of relevant points and the state of the structure in at least one residual relevant point. The state of the structure is detected in a plurality of relevant points under operating conditions. The state of the structure is estimated in at least one residual relevant point by the associated neural network on the basis of the pre-established associated relationship.

Abstract: An apparatus and method are provided that allow a diagnostic tool to communicate with a data link connector in a vehicle and place the vehicle in a desired state for diagnostic testing. A cable that can automatically multiplex its connections in order to make the appropriate connections between the diagnostic tool and the data link connector based on a communication protocol of the vehicle under test. A connector allowing for selective switching of pins of the connector to jump connect the selected pins. This allows the vehicle to be placed in the proper state for diagnostic testing and the diagnostic tool to communicate with the data link connector regardless of the pins being used by the communication protocol of the vehicle.

Abstract: A system and method is presented for diagnosing problems in a sensor, a vehicle computer and a vehicle sensor wiring harness. The diagnostic system comprises a sensor simulator configured to be selectively coupled to the vehicle computer via a wiring harness during a diagnostic mode, and to eliminate and simulate a known good sensor to the vehicle computer by way of the vehicle sensor wiring harness directly connected therebetween. The system includes an external computer adapted to selectively couple the sensor simulator to the vehicle computer, and a user keypad and memory to receive and store user commands of a selected manufacturer's make, model, year of vehicle, and the function type of the selected sensor, and to enable the user to select or adjust a typical operational value comprising one or more of a voltage, current or resistance operational range values of the selected sensor.

Abstract: The technology disclosed relates to testing of connected vehicle systems. The connections involved are sometimes referred to as Car-2-Car (C2C), Vehicle-to-Vehicle (V2V), Car-2-Infrastructure (C2I), or Vehicle-to-Infrastructure (V2I). More generically, the connections are referred to as C2X and V2X. The technology disclosed provides an over the wire simulation of signals that a system will receive in operation, which allows testing of algorithms, breadboards, prototypes and complete systems. The system simulates the position of multiple on board units as the move with the vehicles that carry them. It attenuates signals between the OBUs and can attenuate signals among the OBUs and other test components, including roadside units and synthetic OBUs. The simulation is can be practiced as a method, a device, or computer readable medium that causes a device to practice the method or that, when combined with appropriate hardware, produces the device.

Abstract: Method for determining wear of a friction plate of an automatically actuated friction clutch, particularly in a motor vehicle driven by an internal combustion engine, wherein initially at a prescribed clutch slip and a prescribed clutch torque in an earlier friction lining test point an earlier clutch actuation travel is determined and stored, later again at the prescribed clutch slip and the prescribed clutch torque in a later friction lining test point a later clutch actuation travel is determined, thereafter the earlier clutch actuation travel and the later clutch actuation travel are compared to each other and a differential value is determined, and thereafter a friction lining wear is determined using the differential value, in order to reliably determine friction lining wear in a time interval and with only little effort, so that a depreciation of function due to a worn friction lining can be prevented in a timely manner.