CLOSED LOOP: dual clutch transmissions

HTG GCU offers closed loop, continuous adaptation, self learning algorithm for all dual clutch platforms since GCU 1.1.x firmware version. Using CL takes away all user tuning needs other than defining target for GCU to learn. Such target is dependent purely on driver preferences.

CL is a very sophisticated method delivering very easy solution out of the box. To make it happen prerequisites have to be checked carefully and steps followed as instructed to make learn-in process as quick and precise as possible.

STATIC ADAPTATIONS:

OUTPUTS adaptation should be performed in operating temperature and is MANDATORY. If You’re migrating from CL firmware to newer see release notes if fresh adaptation is required or not.

TRANSMISSION adaptation should be performed in operating temperature. To perform TRANSMISSION adaptation follow on screen instructions. Throughout this adaptation process engine should be IDLING stably. This step adapts selection, line pressure and clutch pressures. Once TRANSMISSION ADAPTATION is over You’re ready to start CL DYNAMIC ADAPTATIONS.

OUTPUTS adaptation lasts around 1 minute, TRANSMISSION adaptation lasts usually up to 5 minutes.

SHAFT SPEED SIGNALS STABILITY:

DC CL relies on clutch angle data and therefore it requires properly functioning Frequency inputs. Those signals can be verified using following datalog channels: “Out: Input Shaft Speed”, “Out: Clutch Slip A”, “Out: Clutch Slip B”.

DCT (GS7) and DQ500 gen.2 (BOSCH) users – we suggest using “Noise suppression PCB for DCT and DQ500 gen2” that can be found on HTG e-Shop to rectify existing noise issues or to protect from possibility of such occuring.

TORQUE CALCULATION:

All adaptation values are stored in functions of LOAD. RELIABLE torque is mandatory in this application. OEM ECUs that calculate load internally usually have it included in CAN datastreams (if such datastream is predefined in GCU, LOAD should be included there also) and are usually most reliable TORQUE sources. If ECU does not report TRQ, latest “FUEL model (calc)” is MANDATORY. See more in Torque Estimation strategy

BASE TARGET SETUP CL US rate and CL DS rate tables have to be set with reasonable values prior to driving. See table descriptions for more information and suggested starting points screenshots below (of course torque range may be different so adjust to Your own needs).

LEARNING PROCESS:

1. VERIFY CONFIGURATION
   1. Is torque input working correctly?
   2. Is shift method (in tables) and take-up method (in general settings) set to CLOSED LOOP?
   3. Is brake input configured?
   4. Do You have space to let car roll forward and backwards?
   5. Are base target tables set correctly?
2. TAKEUP (TU) LEARNING:
   1. Place vehicle on FLAT and LEVEL surface without obstacles – adaptation requires to roll car some distance in each direction.
   2. Hold brake pedal
   3. Engage D or M or R mode.
   4. TU learning is performed – You can notice clutch pressure gradually building and dropping until GCU finds pressure level causing smooth and continuous creep.
   5. Once learning is done GCU won’t drop pressure anymore and car will keep on creeping forward.
   6. Push the brake and come to complete stop. Engage next gear and repeat the process. Once You’ve performed TU on gear 1 and 2 move to next phase.
3. BASE DRIVE PRESSURE LEARNING:
   1. Allow car to TU fully in gear 1 and accelerate lightly as high as it is possible in Your conditions and allow car to decelerate with engine braking back to creep speed. If possible repeat process couple times, possibly introducing slight torque.
   2. Stop and move to gear 2 or perform off load UP shift while decelerating and repeat above procedure.
   3. Above steps adapt base values for driving at each of the clutches. Once both clutches have their base values start up shifting on LIGHT LOAD and repeat acceleration and deceleration process at higher gears and speed. THE MORE YOU DRIVE AND ACCELERATE AND ENGINE BRAKE, THE MORE PRECISE CLUTCH PRESSURE IS GOING TO BE.
   4. Gradually increase torque while driving and shifting, preferably performing 2 full gear swipes at each load. NOTE:Do not perform high power shifts unless you did acceleration and deceleration with such load.
   5. Shifts will learn constantly and will target values in CL US/DC tables.
   6. Having shifts adapted at decent level, LOADED downshifts may be executed as well.
   7. Adaptation results are executed immediately but stored permanently while stopped and switched to N or P. Remember to do it by the end of the drive.
4. VERIFY and MODIFY target tables.
   1. Adjust shift rates and preparation times up to Your preferences. Progress and target can be compared using “Out: Input shaft speed” and “Out: CL Input shaft speed target”

If for some reason You need to reset learned values please use “ERASE LEARNED VALUES” option in adaptation tab. If You need to redo LP adaptation, please perform STATIC TRANS ADAPTATION. You can check HTG YouTube channel for instructional videos.