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Explanation of terms Easytronic (F13+ MTA/F17+ MTA) Programming transmission parameters -- TECH 2 transmission main menu "Additional functions" -- submenu "Program transmission parameters When determining the gear, the transmission works through the H-shift pattern and the gears are engaged. During this process the reference position is determined first. This is necessary so that the Easytronic control has a defined point for making the comparison for the other gears. Once the reference point has been determined, all the further gears are engaged one after the other and the gear geometry is determined (limit positions, at rest positions, gate widths and gate positions). As deadlocks can occur in the transmission during determination, it is necessary to guarantee that the wheels can turn freely (use a lifting platform!). Therefore it is possible when learning a gear that the gear wheels can twist and the gear wheels are not deadlocked. To determine the synchronisation thresholds, a difference in the speed of rotation is needed between the transmission input threshold and transmission output threshold. The engine must be idling to do this. The footbrake and handbrake must be on for safety reasons. The reason for this is that when determining the synchronisation thresholds the clutch is closed and the transmission actuating mechanism moves in the direction of gear synchronisation. This movement against the synchronisation creates a brief friction lock caused by the cone on the synchronisation. If the foot- and handbrake are not activated, this could cause unintentional movement of the vehicle. Determination of the synchronisation thresholds is only started when the signals from the foot- and handbrake are present. As soon as one of the brakes is no longer detected, determination of the synchronisation thresholds is discontinued. Determining the contact point (1 and 2) -- TECH 2 transmission main menu "Additional functions" -- submenu "Determining the contact point The contact point is the position at which the thrust plate and the clutch disc touch and transfer a small torque (approx. 4 Nm . The control unit is despatched with a preset contact point. This characteristic value varies as a consequence of clutch and vehicle tolerances. Therefore this parameter must be determined when the vehicle is first used. It is always necessary to determine the contact point before high friction energies are transferred by the clutch for the first time to prevent premature damage to the clutch. The contact point is determined in 2 stages:
Contact Point Determination Method 1 The system starts from the position 18.00 mm (clutch entirely open) and moves slowly to smaller values until a change in the engine torque ( 4 Nm ) becomes noticeable. The relevant clutch position is stored. Then the clutch is opened again. Contact Point Determination Method 2 Contact point 2 is detected directly after detection of contact point 1. The value is thereby determined more precisely on the basis of the approximate contact point. The contact point is automatically detected twice in succession. The position determined by contact point detection 1 is approached and the engine torque is checked on the basis of the change of 4 Nm and transferred by the clutch depending on the actual change in engine torque of the previously set contact point. Variant programming (High-Speed CAN bus programming) - TECH 2 transmission main menu "Programming" - submenu "Programming variant configuration" The high-speed CAN config list must be programmed depending upon the vehicle equipment. In this process, it is specified whether the vehicle, for example, is equipped with ABS/ESP. If the programming is incorrect, malfunctions or entry is in the error log are to be expected. Read out/delete error log - TECH 2 transmission main menu "Trouble codes" - submenu "Trouble codes in order of priority / Read trouble code from control unit Error recognition is integrated into the control unit software to improve diagnostic testing of the overall system. As soon as an error is recognised, a certain error code is stored in the error memory relating to the type of error. An existing error memory entry remains in the memory until the error memory is deleted. The control unit distinguishes however between an error that is actually still present or one that is no longer present. Moreover, error codes are sub-divided further using a symptom code so that precise information can be retained about the individual error. If an error is recognised, the control unit reacts using certain strategies and error displays. Additional information relating to error codes, error causes and error rectification measures are contained in the test instructions. Crawl mode The Easytronic system includes a creep function. Creeping enables the vehicle to move of gently at idling speed, with the car in gear and without the brake activated. The clutch is partly closed during this. This enables convenient manoeuvring and parking. The creep torque is decreased in a linear manner if the clutch temperature is increased. If the creep function is out of order, this indicates that the clutch hydraulics need to be bled and/or the contact point needs to be reset. Clutch energy input (slippage) Whilst the vehicle is operating, energy is brought into the
clutch during slip. The difference in speed occurring between the
engine output speed and the transmission input speed when
transferring torque is designated slip. The greater the energy
entering, the greater the heating of the individual components of
the clutch. The individual components of the clutch have specific
temperature limits, above which irreversible changes occur and
therefore its function and characteristics are impaired. Clutch protection function To protect the clutch from overload the software incorporates a protection function. This monitors the clutch slip situation and detects "permanent slippage" if the sum of the friction energy exceeds a situation and gear-dependent threshold. A distinction is made between travelling, starting, creep mode, starting under load, normal start and gears "1", "2" and "R". A stall situation (hand-brake or brake-pedal braking of vehicle and simultaneous accelerator actuation) is handled separately.
Friction value The friction coefficient used in the Easytronic control does not correspond to the physical friction coefficient on the lining of the clutch disc. The Easytronic friction coefficient is a software calculation value with which the characteristic curve for the actuating torque, filed in the software, can be adjusted to the actual characteristic curve. The Easytronic friction coefficient is a factor which acts on the clutch torque (friction coefficient adaptation). The friction coefficient contains all the influences which change the transmission characteristics of the clutch torque as a function of the actuator path (actuating torque characteristic curve). This includes the transmission distance, thermal effects on the clutch, the physical friction coefficient, friction radius etc. or additional electrical consumers which affect the engine torque. Adaptation Adapting the programmed data whilst driving is called adaptation. The characteristic curve and transmission geometry data in the control unit are continuously adapted to the actual conditions, e.g. the routine clutch characteristic curve is adapted for the control system using the contact point and friction value parameters during operation. Friction value adaptation The friction coefficient is adapted in the vehicle. To do this the engine torque signal and the actuator path are evaluated in a slip situation (e.g. starting off or changing gear). The Easytronic control changes the clutch torque with the friction coefficient factor in such a way that the nominal actuating torque characteristic curve (filed in the control) approaches the actual characteristic curve. Contact point adaptation Contact point adaptation serves to compensate for thermal and/or wear-related shifts of the characteristic clutch curve. Contact point adaptation is carried out when the vehicle is standing, the engine is running, the brake is actuated and a gear has been selected. Adaptation of transmission geometry data Each time a new gear is engaged, the transmission geometry is scanned in the shifting and selecting direction. Deviations from the values learnt at commissioning are evaluated and lead in the long term to changes in the values filed. In this way adaptation is made to changes in the transmission geometry over the life of the vehicle (e.g. because of wear). Sniffing borehole The snuffle bore is a small aperture in the master cylinder. It permits fluid compensation and therefore length compensation in the release system (snuffling) via a compensation tank which serves as a pressure reservoir. This process, which is also designated compensation, is necessary to compensate for changes in the volume of liquid caused by temperature fluctuations or reduction in the volume of fluid because of loss of fluid or wear. Torque tracking Without torque tracking, the clutch actuator only moves to the positions fully open or fully closed. With torque tracking, the required position of the clutch actuator is always dependent on the current engine torque (clutch characteristic curve torque/path). To attenuate the load changes, the required clutch torque is stated as the engine torque multiplied by a safety factor. Therefore the system reacts to rapid increases in engine torque with a briefly slipping clutch. In addition, torque tracking in the part load range enables the clutch to open quickly. Torque tracking is restricted for small torques by a minimum clutch torque. The "Torque tracking switched off" replacement strategy is
implemented in the case of some errors. Synchronisation Due to the different speed on the transmission input shaft and the transmission output it is necessary to adjust the speed of the shaft when changing gear, or to synchronise them, in order to be able to select the gear. This is achieved in the transmission system using a synchro ring. When changing gear the sliding bush is shifted in the direction of the tooth gearing of the gearwheel. This thereby takes the synchro ring with it which is then pressed against the outer cone. Due to the different speeds of the parts that are to be connected, the synchro ring turns a little against the sliding bush. This activates the locking device. The teeth of the synchro ring press against the sliding bush and prevent further slippage. The pressing force pushes both cones together until their respective speeds have been compensated. Only then does the sliding bush shift over the tooth gearing and the gear is engaged. The synchronisation process is required when changing up and down gears. The synchro ring is located in the transmission in front of the end position of the gear and is determined as an individual parameter during commissioning. This position at which the synchronisation takes place is known as the synchro threshold. Auto "N" function If the service break is applied and a starting operation begun at the same time, an automatic shift to "N" is performed in dependent of the previously selected gear. |
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