new MPS6 Powershift transmission with a 3-shaft design for I4 and V6 in C- and
CD- cars and on the other hand the SPS6 Powershift transmission with an ...
Transmission Systems for Hybrids
Summary
Powershift - New Transmission Technologies Today’s car industry is requesting higher performance from transmission technologies in terms of efficiency, speed, torque and flexibility in launch and shift characteristics. The newly developed double-clutch transmissions from GETRAG FORD Transmissions combine the advantages of conventional six-speed manual-shift gearbox with the qualities of a modern automatic transmission. Two variants with a torque range up to 450 Nm are explained, on the one hand the new MPS6 Powershift transmission with a 3-shaft design for I4 and V6 in C- and CDcars and on the other hand the SPS6 Powershift transmission with an extremely short 2x2 shaft design for I5 and I6 in CD-car and SUVs. The design of such Powershift transmissions, which provides excellent acceleration without any interruption of powerflow, is shown and the technologies to meet customers’ requirements of immense agility and driving pleasure are explained. The modular design and manufacturing principles demonstrate cost and resource orientated production: design highlights like the hydraulic gear change and clutch actuation, the integrated TCU, the parallel wet clutch and 3-chamber oil management demonstrate newest product technologies:
•
The benefits of the hydraulic concept are a commonized and compact main control, reduced number of cost-intensive variable force solenoids and good
controllability during shifting, excellent clutch controllability, improved thermal stability for creep & hill hold with improved cold shiftability. •
An integrated control unit for double-clutch transmission guarantees gear shifting in milliseconds, with a silky-smooth shifting without jerks or interruption of tractive force.
•
The benefits of parallel wet clutch design are excellent controllability and robustness due to fully centrifugal compensation on both clutches, equal gains on both clutches and separate lube/cooling for both clutches.
State-of-the art control software architecture with an automatic shift strategy for drive situation detection and shift scheduling and a drive line manager who coordinates all modules required for changing gears complete the design walk of the Powershift transmissions Detailed efficiency measurements for gasoline and diesel applications underline the remarkable improvements in fuel consumption.
Hybrid Extension of Powershift Technology Hybrids have to be seen on a technology migration path for transmissions. State of the art automatic transmissions will be enhanced to hybrid aggregates, thus providing the entry ticket in electric driving era. The key drivers for hybrids are changing environmental conditions, constraints in oil supply, high oil prices and the need for technological differentiation among OEM’s. For Hybrid to become a commercial success it is important to find sound business cases like in commercial vehicles with electric range or extremely fuel saving passenger cars. GETRAG FORD Transmissions looks upon its system as a 2nd generation Hybrid based upon dual clutch transmission technology and the use of two electric machines sized 15-25 kw. This system enables parallel and serial hybrid operation. The size of the electric motors does not need adaptation to combustion engine size due to the parallel hybrid
concept as opposed to an E-CVT. The system allows engine downsizing through massive boosting, regenerative braking, start stop, hill hold and electrical reverse in serial hybrid mode without battery storage constraints. Dual clutch transmission functionality is uncompromised. The project is currently in the early prototyping phase. In a comparison of operating modes of hybrid electric powershift (HEPS) and a powersplit hybrid layout which is in production is it particularly evident that Powershift based hybrid technology has significant advantages in steady state long distance driving compared to powersplit technology, which makes HEPS an excellent solution for North American and European customer usage.
4th International CTI-Symposium Innovative Automotive Transmissions 4. Internationales CTI Symposium Innovative Fahrzeug-Getriebe 5 to 8 December 2005, Berlin, Germany
Transmission Systems for Hybrids
Together for Success
Rolf Najork, GETRAG FORD Transmissions
06/07-Dec-2005 / Rolf Najork - CTI Berlin
Overview • • • • • •
Business Environment SHEPS/HEPS Concept Powershift Base Transmission Operating Strategy Projected Fuel Economy Savings Conclusion
06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 2
Together for Success
Overview • • • • • •
Business Environment SHEPS/HEPS Concept Powershift Base Transmission Operating Strategy Projected Fuel Economy Savings Conclusion
06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 3
Together for Success
Drivers for Hybrid Expansion •
Security of oil supply - political instability in Arab World and shrinking oil reserves will drive fuel efficient vehicles
•
Increasing emission restriction - further challenges for diesels, reducing the cost gap between Hybrids and Diesels
•
Competitive pressure - OEMs setting the pace in environmentally friendly products and market them well
•
Technology shift - Hybrids provide entry in electric driving era, creating the basis for fuel cell technology
•
Western OEM’s need next-generation vehicles to maintain competitive advantage low cost competition from emerging markets
06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 4
Together for Success
Market Projection on Hybrid Sales 3M Projection 2015 Actual 2004
1M 83000 USA
60000 Japan
1M 12000 Europe
The projection is based on a publication by Prof. Dudenhoeffer
06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 5
Together for Success
Business Case Scenarios for Hybrids We need to define market niches for Hybrids to design systems that meet customer needs and can be sold profitably • Performance hybrid vehicles diesel and gasoline for Europe and US without trailer towing restrictions (significant advantage over conventional diesel powertrains required) • Quiet and zero-emission passenger cars that can access areas which are not permitted for conventional cars (taxi driving, pedestrian zones, holiday resorts, private customers with focus on environment) • Light Trucks for special delivery zones (pedestrian zones, hotels, hospitals) • Commercial Vehicles which need power supply 220V/2000W for business purpose, camping and outdoor occasions
06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 6
Together for Success
Overview • • • • • •
Business Environment SHEPS/HEPS Concept Powershift Base Transmission Operating Strategy Projected Fuel Economy Savings Conclusion
06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 7
Together for Success
GFT Hybrid Requirements •
Torque split instead of power split
•
Parallel and serial hybrid operation
•
Power transferred mainly through mechanical path
•
Wide range of ratios and speeds within gearbox (reduced size of electrical motors, mechanical fallback layer)
•
Significantly reduced need for battery capacity (cost and weight impact)
•
Deliver economy far superior to classic diesel powertrains
•
Capability for mild and full hybrid functionality
06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 8
Together for Success
Powershift Concept HEPS / SHEPS • Dual clutch base transmission • 2 electric motors (scaleable for power and battery size) • Electric motor power 15 and 25 kW (total 40 kW) • Gearbox integrated design for package and installation benefits • Start/Stop at standstill and during drive (electric coasting, full electric drive – depending on energy storage size) • Recuperative breaking / electric boosting • Hill hold, launch and reverse electrically assisted
06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 9
Together for Success
Overview • • • • • •
Business Environment SHEPS/HEPS Concept Powershift Base Transmission Operating Strategy Projected Fuel Economy Savings Conclusion
06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 10
Together for Success
MPS6/SPS6 Concept MPS6 (3 shafts)
06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 11
SPS6 (2x2 shafts)
Together for Success
Extension Hybrid MPS6 Base
Mild Hybrid
06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 12
Full Hybrid
Together for Success
Extension Hybrid SPS6 Base
Mild Hybrid
06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 13
Full Hybrid
Together for Success
Packaging of Electric Motors
06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 14
Together for Success
GFT Full Hybrid Powershift Concept HEPS* • Based on XPS lay shaft transmission architecture (parallel clutch) • Two electric motors acting on input shafts Configuration allows for a multitude of working modes (serial & parallel) EM 1
Current SPS6
1,3,5 ICE
FD 2,4,6 EM 2
* Patents pending (Torque split vs conventional Power split approach) 06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 15
Together for Success
GFT Short Hybrid Powershift Concept SHEPS* • Based on XPS lay shaft transmission architecture (parallel clutch) • Two electric motors, one connected to crankshaft, one connected to input shaft Configuration allows for a multitude of working modes (serial & parallel) EM 1
Current SPS6
1,3,5 ICE
FD 2,4,6 EM 2
* Patents pending (Torque split vs conventional Power split approach) 06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 16
Together for Success
Overview • • • • • •
Business Environment SHEPS /HEPS Concept Powershift Base Transmission Operating Strategy Projected Fuel Economy Savings Conclusion
06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 17
Together for Success
Comparison of different driving modes (1) HEPS versus Power-Split
Engine start at standstill HEPS
Power split type
EM 1 EM 1 1,3,5 ICE
FD
ICE
P/S
FD
2,4,6
B
EM 2
• Insensitive to EM control (no talk-through of variations) • Both EMs available (cold start)
06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 18
B
EM 2
• Sensitive to EM control (variations feel able in vehicle) • Only one EM available (other EM needed to counteract start torque) Together for Success
Comparison of different driving modes (2) HEPS versus Power-Split
Launch with engine running HEPS
Power split type
EM 1 EM 1 1,3,5 ICE
FD
ICE
P/S
FD
2,4,6
B
EM 2
• Normal launch without any EMs possible • Boosting during launch with both EMs possible • Launch torque limited by transmission torque only 06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 19
B
EM 2
• One EM works as generator, one EM works as booster • ICE launch torque limited by EM (generator) size
Together for Success
Comparison of different driving modes (3) HEPS versus Power-Split
Creep or Reverse HEPS
Power split type
EM 1 EM 1 1,3,5 ICE
FD
ICE
P/S
FD
2,4,6
B
EM 2
• Boosting during launch with both EMs possible • Normal launch without any EMs possible • Launch torque limited by transmission torque only 06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 20
B
EM 2
• One EM works as generator, one EM works as booster • Electrical IVT
Together for Success
Comparison of different driving modes (4) HEPS versus Power-Split
Normal driving (complete range) HEPS
Power split type
EM 1 EM 1 1,3,5 ICE
FD
ICE
P/S
FD
2,4,6
B
EM 2
• Pure mechanical drive (high efficiency) • Boosting with both EMs possible (depending on battery capacity) • Recuperative braking with one or two EMs • 6 speed transmission with powershift • ICE power independent of EM power 06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 21
B
EM 2
• Up to 1/3 of the energy transferred electrically • One EM works as generator, one EM works as booster • Drives as CVT • Maximal ICE power depending on maximal EM power Together for Success
Comparison of different driving modes (5) HEPS versus Power-Split
Normal driving (specific speed range) HEPS
Power split type
EM 1 EM 1 1,3,5 ICE
FD
ICE
P/S
FD
2,4,6
B
EM 2
• Pure mechanical drive (high efficiency) • Boosting with both EMs possible (depending on battery capacity) • Recuperative braking with one or two EMs • 6 speed transmission with powershift • ICE power independent of EM power 06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 22
B
EM 2
• Lock-up clutch engaged • Boosting with one EM possible (depending on battery capacity) • Drives with designed ratio (high efficiency) Together for Success
Comparison of different driving modes (6) HEPS versus Power-Split
Electric drive HEPS
Power split type
EM 1 EM 1 1,3,5 ICE
FD
ICE
P/S
FD
2,4,6
B
EM 2
• Electric drive with one or two EMs possible • Torque can be multiplied by ratio
06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 23
B
EM 2
• Electric Drive in base configuration only with EM2 • If ICE is braked by sprag clutch, electric drive with both EMs possible • Torque limited due to constant ratio Together for Success
Comparison of different driving modes (7) HEPS versus Power-Split
Start/Stop HEPS
Power split type
EM 1 EM 1 1,3,5 ICE
FD
ICE
P/S
FD
2,4,6
B
EM 2
• Launch during engine start possible • After engine start, boosting with two EMs possible
06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 24
B
EM 2
• Start/Stop implemented by control of EM1 • Quality of Start/Stop is depending on control strategy Together for Success
Overview • • • • • •
Business Environment SHEPS/HEPS Concept Powershift Base Transmission Operating Strategy Projected Fuel Economy Savings Conclusion
06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 25
Together for Success
Simulation Model for Fuel Economy Investigations
• Matlab Simulink based simulation • Detailed complete vehicle model with major parasitic losses • Engine, transmission, auxiliary drives maps included 06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 26
Together for Success
NEDC Fuel Economy Simulations (Hybrid Drive Strategy vs ICE Mode)
Speed [km/h] ICE base torque [Nm] ICE Hybrid torque [Nm] EM1 torque [Nm] EM2 torque [Nm]
Speed [km/h] ICE base torque [Nm] ICE Hybrid torque [Nm] EM1 torque [Nm] EM2 torque [Nm]
06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 27
Together for Success
Performance and Fuel Efficiency (Assumption Equal 0-100 Performance)
Gasoline, 400Nm Gasoline, 320Nm Gasoline, 320Nm+2*EM
Equal 0-100 acceleration
06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 28
Gasoline, 400Nm Gasoline, 320Nm Gasoline, 320Nm+2*EM
Pure electric drive
Together for Success
Drive Modes During City Driving Efficiency Optimized Driving
= ICE running, EMs used as generators charging battery = ICE off, electric coasting with one EM, battery discharging = ICE off, recup breaking with one or two EM, charging battery = All off during idle 06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 29
Together for Success
Drive Modes During City Driving Emissions Optimized Driving
= ICE on, boosting with EMs, battery discharging = ICE on or off, charging battery with EMs or electric coasting = ICE off, recup breaking with one or two EM, charging battery = All off during idle 06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 30
Together for Success
Simulation Roadmap in NEDC Base: SUV, Gasoline 400Nm, torque converter automatic transmission Hybrid: SUV, Gasoline 320Nm, DCT based (2*20kW, 150kg additional weight) Software complexity 1
2
3
4
Mild Hybrid with ISG. Fuel consumption change (EC00) Performance change (0-100 km/h)
1 -5%
2
Full Hybrid 2x20KW Rule based strategy. No Battery SoC)
Hardware Complexity
-24%
3
+1%
-9%
Full Hybrid , ext. rule based strategy modified gearbox enhanced batt -25%
-1%
Full Hybrid 2x20KW.Rule based strategy. SoC feedback -21%
-9%
Full Hybrid Ext. rule based strategy incl SoC feedb. enh.batt. Mod gear. -30%
-1%
Full Hybrid 2x20KW. Rule based strategy. SoC feedback, Gear shift control. -28%
-1%
Full Hybrid Ext. rule based Strategy SoC feedb. Gearshift Ctrl enh. batt mod gear
-32%
-1%
Full Hybrid 2x20KW Evolutionary algorithm for optimal solution (time ind.) -36%
NA
Full Hybrid Evolutionary algorithm for optimal,enh. Batt. mod. Gear. -33%
NA
F/E Opportunities: •DCT: 5% (incl. weight handicap) •Downsizing: 5% •Base hybridization (Start/Stop, Boosting, Recuperative braking, low speed E-Drive): 15% •Enhanced hybridization (special DCT modes, evolutionary algorithms, GPS): up to 11%
06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 31
Together for Success
Overview • • • • • •
Business Environment SHEPS/HEPS Concept Powershift Base Transmission Operating Strategy Projected Fuel Economy Savings Conclusion
06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 32
Together for Success
Conclusion •
DCT technology provides an excellent basis for Hybrid
•
Torque split with multiple gears instead of power split improves steady state fuel economy
•
Reduced size of electric motors, power electronics and battery
•
Hybrid transmission electric motor power widely independent from combustion engine power
•
Mild hybrid and full hybrid option
•
Parallel and serial mode operation
•
Significant fuel economy improvements
06/07-Dec-2005 / Rolf Najork - CTI Berlin / page 33
Together for Success