Zf Friedrichshafen Ag

Maik Wurthner

Joachim Staudinger

Ingo Sauter

Johannes Kemler

Werner Wolfgang

Peter Herter

Ulrich Reith

Bertram Wengert

Alexander Maier

A method of operating a drive-train which comprises an automated shift transmission having an unsynchronized main transmission and a synchronized downstream group that is drivingly coupled downstream from the main transmission. An input shaft of the automated transmission is connected, via a clutch, to a drive aggregate and an output shaft of the automated transmission is connected to a drive axle. When the vehicle is driven and the main transmission is in a neutral position, if the drive aggregate malfunctions, to engage a gear, the downstream group is adjusted to stop transmitting power and thereby coast to a stop. A shifting impulse is applied to a shifting cylinder of the main transmission so that shifting elements, of the main transmission, ratchet over one another and eventually mesh thus engaging the main transmission, and once the main transmission is engaged, the downstream group is brought to a power-flow-transmitting position.

Method for operating a drive train

A method of controlling a rolling or coasting function of a vehicle with a drive train having a drive motor, an automatic or automated transmission, a controllable shifting means, a brake device and a drive speed control device. The vehicle speed is regulated by the drive speed control device and the braking device is activated, as needed, when driving on a downhill gradient section. To effectively and reliably use the rolling or coasting function in suitable driving situations, taking into account the influence of the driving speed control device, a rolling or a coasting condition for a downhill gradient taper is checked, when driving on the downhill gradient section, and, when the rolling or coasting condition is satisfied, the transmission controls interrupt the flow of power in the drive train before the vehicle entering a flat area, and/or before the driving speed control device generates an engine torque request.

Method for controlling a rolling or coasting function of a vehicle

A method of controlling a rolling or a coasting function of a vehicle, such as a commercial vehicle, having a drive train including a drive motor, an automatic or automated transmission that is controllable by transmission controls, a controllable shifting mechanism for interrupting the flow of power in the drive train, and a driving speed control device. The flow of power in the drive train is interrupted in a suitable driving situation. In order for the rolling or the coasting function to be exploited as efficiently as possible, and still be terminated safely and comfortably, the flow of power in the drive train is restored depending on a selectable difference in speed (&#x394;v_F_T) between the current vehicle speed (v_F) and a speed limit (v_T) set by the driving speed control device.

A method of initializing the mass of a motor vehicle after a restart, for controlling a starting process of the motor vehicle a from a standstill. During operation of the motor vehicle, its mass is computed and the determined mass values are stored and, from the stored mass values, a vehicle-specific maximum mass value and/or a vehicle-specific minimum mass value is determined. The vehicle-specific maximum mass value and/or the vehicle-specific minimum mass value, determined in this manner, is subsequently used for initializing the mass of the motor vehicle after restarting the vehicle.

Method for initializing the mass of a motor vehicle

A method of determining the size of a gear interval from a currently engaged gear to a target gear in a transmission. The method includes the steps of, for each current gear and for each possible gear interval from the current gear, recording a limit value for an acceleration or a deceleration in the target gear corresponding to the current gear and the respective gear interval used; for the current gear, starting with the smallest gear interval, applying a loop with successive increases of the gear interval to determine, depending on the current driving situation and characteristic parameters of the vehicle, the acceleration or the acceleration theoretically obtainable in the target gear produced by using the gear interval, which is compared with the respective recorded limit value until the acceleration or the deceleration theoretically obtainable no longer contravenes the limit value. The gear interval is then selected for a gearshift.

Method to define a gear step for a shifting

A transmission control device () for an automatic or automated transmission (). A shifting strategy of the transmission control device () controls and/or regulates the operation of the transmission () based on driving condition data such as vehicle mass, driving resistance, vehicle inclination, vehicle velocity, vehicle acceleration, engine rotational speed and/or engine torque, and based on data about the driver's wishes. The transmission control device () continuously calculates the driving condition data of the vehicle mass, driving resistance and/or vehicle inclination based on topographic data of a current position of the motor vehicle, and/or the shifting strategy determines a gear change from an actual gear into a target gear based on topographic data of a defined distance ahead of a motor vehicle. The defined distance ahead of the motor vehicle depends on the currently velocity of the vehicle.

Gearbox control device

A method of operating a vehicle in a freewheel mode or a rolling mode, in which the vehicle has a drive train comprising a controllable drive engine, an automatic or automated transmission, and a controllable shifter for interrupting a flow of power in the drive train. To enable fuel-efficient and low-emission, as well as safe and comfortable driving, it is intended that the freewheel mode or the rolling mode is prognostically activated, deactivated or retained by performing a plausibility check of a currently active, automatic driving speed control function or a driving speed and a distance control function and/or other current driving operation or driving state data. The method includes coordinating and adapting relevant marginal conditions of the active driving speed control function or the driving speed and the distance control function, and of the freewheel mode or the rolling mode, according to the driving situation, and initiating control measures by a transmission control.

Method for operating a vehicle having a freewheel mode or a rolling mode

A method of controlling the driving mode of a motor vehicle, having a largely automated drive-train including a drive motor, a transmission and a separator clutch arranged between the motor and transmission, such that while driving, if certain operating conditions exist and a speed profile calculated with reference to topographical data and vehicle parameters for a road section lying ahead is suitable, the drive-train is disengaged and driving continues in a coasting mode until the occurrence of a termination signal. To enable coasting operation, the calculated speed profile for the case of immediate opening of the drive-train is determined continually at equidistant successive travel points along the driving stretch and is, in each case, evaluated in relation to lower and upper speed limits. Coasting is only enabled if, for a specified minimum number of successive travel points, the evaluation result is in each case positive.

Method for controlling the driving mode of a motor vehicle

A method of controlling a shifting operation in an automatic transmission of a commercial vehicle. A targeted gear and an associated target rotational speed are determined, via a transmission control, depending on predetermined parameters, and the shifting operation is executed upon reaching a determined shifting rotational speed. A shift interlock is activated, at least temporarily, during a downshifting operation when, upon reaching the shifting rotational speed, the determined target rotational speed lies below a predetermined rotational speed limit.

Method for actuating a shifting operation in an automatic transmission of a utility vehicle

A method for automatically determining a current offset value for the zero-point correction of a vehicle inclination sensor including the steps of while driving in a first driving direction, the current driving resistance is determined repeatedly, without regard to the sensor and stored temporarily, and a current raw signal value of the sensor is noted. Upon a change in the driving direction, the last-noted raw signal value is stored temporarily and while driving in the second driving direction. The current driving resistance is determined repeatedly, without regard to the sensor and stored temporarily. Then, if the difference between the two stored driving resistances agree with a tolerance threshold, the noted raw signal value is stored as the offset value for the zero-point correction of the inclination sensor.

Method for calibrating a slope sensor

A method for controlling a drive train of a motor vehicle comprising a drive engine, an automated transmission, and an automated clutch arranged in the force flow between the drive engine and the transmission. In order to achieve low component wear, a comfortable coasting operation mode and a spontaneous transition into the traction mode, it is provided that additional coast downshifts are prevented as soon as the driving speed (v) of the motor vehicle has reached or dropped below a previously defined threshold speed (v) for coast downshifts (v&#x3c;=v), or the currently engaged gear (G) corresponds to a previously defined limit gear (G) for coast downshifts (G=G) and, after dropping below the threshold speed (v) or after engaging the limit gear (G), a transition into the traction mode is prepared by determining a current target gear (G) and an associated shifting speed (n) of an adaptive shift for the transition into the traction mode as a function of the driving speed (v) of the motor vehicle and/or the engine speed (n) of the drive engine.

Method for controlling a drive train of a motor vehicle

A method for controlling gear shifts in an automated stepped gear transmission of a motor vehicle in which operating parameters of the motor vehicle are continuously determined and evaluated for initiating and carrying out a shift from a currently engaged gear to a target gear such that, before a shift, the shift speed for initiating the shift and the target gear are determined. For better adaptation of the shift, in particular the determination of the shift speed and the target gear, to the current driving and operating conditions of the motor vehicle, the shift types 'shift-speed-orientated shift' and 'target-speed-orientated shift' are provided and, immediately before a shift operation, it is decided, as a function of at least one of the operating parameters in which, of the two shift types, the shift is to be carried out.

Method for controlling shifting of a stepped automatic transmission

A process of controlling and/or regulating an automatic transmission in which a predetermined shifting speed of the gear shift is carried out and adjusted during a shift program, and in which the detection of a constant-speed driving of the vehicle is carried out at least during the shift program.

Method for controlling and/or regulating an automatic gearbox

A method for controlling a vehicle's automated transmission, which is arranged in a drive train in the force flow between a engine and a drive axle or a transfer box, depending on certain operating parameters and control actions of an adaptive cruise control system (ACC) that can be operated using engine and brake mechanisms to regulate speed and distance from a car in front. The method controls the transmission when an engine torque demand differs from the torque demand of the ACC. The operating mode of the ACC, which is active at the time, and the load direction of the torque demand of the ACC are determined, and the torque demand, used for controlling the transmission when speed or distance regulation is activated, is determined depending on the ACC operating mode and the load direction of the torque demand.

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Markdorf, Germany

Maik Wurthner