New Features for more efficient Manual Transmissions with additional Customer Benefit 14th International VDI Congress, Friedrichshafen, Wulf Leitermann, Matthias Brosi, Rafael Prellezo
New Features for more efficient Manual Transmissions with additional Customer Benefit Agenda 1. Global Manual Transmission Market 2. Future Market Requirements for Manual Transmissions 3. New Features for more efficient Manual Transmissions Increased overall Spread and Number of Gears Reduction of parasitic Losses Automated Clutch 4. Next Generation Inline Manual Transmission Family 5. Summary 2
1. Global Manual Transmission Market
1. Global Manual Transmission Market Global manual transmission volumes will increase. Inline manual transmission market is shrinking and moving from passenger cars to light commercial vehicles. Light Vehicle Production < 3,5 t (Passenger Cars and Light Commercial Vehicles) RWD MT Light Commercial Vehicle Production < 3,5 t; > 250 Nm RWD MT Passenger Car Production < 3,5 t; > 250 Nm 4
2. Future Market Requirements for Manual Transmissions
2. Future Market Requirements for Manual Transmissions Further improvements of manual transmissions is requested. Additional functions under consideration, due to customer acceptance and on-costs. New design features requested: Overall spread > 7,5 Oil management Significantly reduced parasitic losses in all components Gears Bearings Seals Additional design features optional: 7-speed gear set Automated clutch Functional aspects considered as standard: Shiftability according specific OEM DNA Fulfillment of NVH targets All features have to consider best cost efficiency 6
3. New Features for more efficient Manual Transmissions
3. New Features for more efficient Manual Transmissions Increased overall spread reduces fuel consumption, but effects transmission and powertrain attributes. Increased overall spread is the major contributor to reduce fuel consumption and emissions down speeding in higher gears 3 4 %, depending on engine and vehicle application Improvement for WLTC slightly higher than for NEDC relative fuel consumption [%] 100,0 95,0 90,0 WLTC Phi = 6,3 Phi = 7,5 But high overall spread effects drivability and design attributes: Feature Challenge Approach Increased gear steps Driving maneuvers @ low speed 7-speed gear set Down-speeding Tractive effort decrease @ high speed Engine characteristic Increased center distance Transmission weight Adjusted design philosophy 8
3. New Features for more efficient Manual Transmissions Reduction of splash loss directly correlates to complexity of chosen technical solution. Passive Oil Management: Oil shield separates gear set from oil sump Controlled oil flow Reduced oil volume Significantly reduced splash losses and oil temperature Active Oil Management: relative splash losses [%] 100 75 50 25 0 Splash losses without vs. with oil shield -40% -54% 1000 1/min 3500 1/min w/o oil shield with oil shield Dry sump lubrication by scavenge pump and injection lubrication Further reduced splash losses but, higher complexity weight costs relative energy loss reduction [%] Energy loss reduction passive vs. active oil management 100 75 50 25 0 NEDC WLTC passive active 9
3. New Features for more efficient Manual Transmissions Further improvement on component level are possible, but to some extent cost-benefit outcome questionable. Component Gear set Bearings Synchronizer Oil Seals Measure Low loss gear design Coating Smaller bearings, due to reduced axial and radial forces Reduces drag torque Reduced number of cones Reduction of viscosity Optimized sealing lip design and reduced preload Manual transmission is a very mature system all efficiency improvement measures to be reflected against - Cost - Customer benefit - End customer acceptance 10
3. New Features for more efficient Manual Transmissions Automated clutch system could improve MT functionality and fuel efficiency Automated clutch system features and advantages: Sailing possible for MTs CO 2 reduction in WLTC ca. 7% in real life even higher Stop-and-go assist Launch control Drivetrain protection NVH improvement by clutch micro slip Add-on automated clutch system components: Clutch actuator + position sensor Clutch pedal + position sensor Control unit (pot. integrated in ECU) Base for MT hybrids! 11
3. New Features for more efficient Manual Transmissions Automated wet clutch concept based on GETRAG DCT technology will offer further advantages. Fully integrated automated wet clutch concept based on GETRAG modules: Wet clutch using DCT components Pump actuator carry-over from DCT Oil suction and cooling based on DCT design features Clutch control using DCT software modules Advantages of integrated wet clutch system: Better controllability of wet clutch system Higher robustness against high energy events Significantly reduced inertia and weight Usage of mass production components and controls 12
4. Next Generation Inline MT Family
4. Next Generation Inline Manual Transmission Family Volatile market and technical requirements needs to be addressed in the next generation inline MT concept Variety of technical requirements 250 800 Nm Different mission profiles (sport car vs. LCV) Number of gears (6 vs. 7-speed) Overall ratio spread Fuel efficiency Segmented inline MT market Premium passenger cars Sport cars LCV? Volatile inline MT volumes Shrinking volumes for premium passenger cars Increasing global volumes for light commercial vehicles (LCV) Common requirements for all applications Best shiftability NVH optimized Flexibility for different applications and innovations Low product costs Best reliability 14
4. Next Generation Inline Manual Transmission Family New flexible inline MT architecture supports huge variety of customer requirements. Major design features: One center distance for all variants Overall spread > 7,5 feasible Reduced axial and radial loads Low loss gear design Carry over components MT/DCT Best shiftabilty and NVH Optimized design costs Protected options: 7-speed gear set module Active oil management Mid and high torque gear sets Fuel efficiency measures New design and manufacturing approach: Mid and high torque derivatives by adjusted gear width Axial flexibility of bearings position and shift system provided Common base of MT and DCT without negative effects on: Weight Complexity of MT and DCT 15
5. Summary
5. Summary New and optimized functionality for manual transmission is feasible and base for GETRAGs new flexible MT architecture Major contributors for fuel efficiency improvement are Increased overall spread for down-speeding potentially 7-speed gear set needed Automated clutch to enable sailing Improvements on component level (oil management, low viscosity oil, low loss gear design ) are feasible Due to cost sensitivity of manual transmissions each optimization has to be crosschecked regarding cost-benefit outcome and could be different for specific applications or markets Technically meaningful features like 7-speed or automated clutch has to be checked against end customer expectation and acceptance GETRAG could offer a new flexible manual transmission architecture, which reflects optimized functionality. New functions are optional. 17