Alternative Module Drives for Mobile Working Machines Dipl.-Ing.(FH) Michael Gallmeier Prof. em. Dr. Dr. habil. Hermann Auernhammer Agricultural Systems Engineering Technische Universität München Germany ATOE Conference 2008 Iguassu, Brazil A08-13 (1)
Requirements resulting from material processing Yield map of sugar beets, field Hergern (Germany) October 2001 Relative flow variability [%] Standard deviation of yield [kg/ha] Combine `02 78 96,2 Combine `03 120 181,1 Mower `01 29 15,8 Mower `02 78 32,8 Beet harvester `02 71 260,7 Maize Chopper `02 134 235,0 Maize Chopper `03 41 108,9 Increased machine efficiency by: Dynamic machine adaptation (KUTZBACH) closed-loop module speed control Closed loop module control systems (BÖTTINGER) Increased driveline efficiency A08-13 (2)
Objectives Problem: Which technology fits future demands? Assessment of alternative drive line concepts for usability in mobile working machines Criteria: satisfying future requirements overall efficiency power to weight ratio overall size of the module drive and the peripheral equipment design aspects costs A08-13 (3)
Methode Field Tests Hydraulic driveline (Series production) Electric driveline (Prototype) M 3~ M 3~ AC DC AC DC DC AC Field Tests G 3~ Electric driveline (Prototype) Monte-Carlo Analysis Typical Loadcycle Test Stand electric hydraulic Hydraulic driveline: Operational behaviour Power-to-weight ratio m P Hydraulic driveline: η η η t driveline t mod ule t transmission Electric driveline: η t driveline ηt mod η ule t transmission Electric driveline: Operational behaviour Power-to-weight ratio m P A08-13 (4)
Carrier Big-X with easycollect A08-13 (5)
Hydraulic Header and Intake Drive 8 9 6 5 2 Dieselm motor Diesel 3 1 7 1. Pumps 2. Motorvgearing 3. Hydr. Intake Drive 4. Hydr. Header Drive 4 5. Gearing 6. Intake Module 7. Split Gearing Header 8. Mech. Driveline Header 9. Chaindrive Gearing Pressure Sensor Flow rate Sensor A08-13 (6)
Diesel-electric Header and Intake drive (without Cooling System) M 3~ AC DC 7 8 4 3 1 Dieselm motor Diesel M 3~ AC DC DC AC M 3~ AC DC 6 5 2 LS G 3~ 1. Synchronous Generator 2. Power switch 3. Rectifier 4. Capacitors DC-Link & Braking resistors 5. Control and Safety 6. DC-Link (400-750 V) 7. Motor with Converter 8. Planetary Gearing A08-13 (7)
Diesel-electric Solution A08-13 (8)
Test Stand Set up 4 3 2 1 1. Header, Intake und Feeding pump at Engine Gearing 2. Hydraulic Header drive with mech. driveline 3. Summation gearing 4. DLG PowerMix Module with mech. Interface 5. Hydraulic Intake drive 5 6 7 8 6. Hydraulic pump system with 100 ccm variable displacement pump 7. Hydraulic Interface DLG PowerMix (DLG hydr ) 8. DLG PowerMix Drawbar Test Vehicle A08-13 (9)
Results Operational behavior during field tests Efficiency during stationary operation Efficiency during dynamic operation Power-to-weight ratio Power density Costs A08-13 (10)
Operational Behavior - Hydraulic and Electric Intake Drive during Field Tests - Pressure 500 300 [bar] 400 [A] 250 300 200 100 Current 200 150 100 50 0-100 0 20 40 60 80 100 120 [l/min] 160 Flow rate Most common operation point 0-50 0 500 1000 1500 2000 2500 [rpm] 3000 Speed I N I max A08-13 (11)
Efficiency of module Drives depending on load (n Diesel =1750 1/min; x th = 8 mm) 1.00 1,0 0.90 0,9 0.80 0,8 0.70 0,7 1 3 Efficiency Factor Wirkungsgrad 0.60 0,6 0.50 0,5 0.40 0,4 0.30 0,3 0.20 0,2 0.10 0,1 0.00 0,0 2 0 50 100 150 200 250 300 Nm 350 Torque Moment load 1 Hydraulic intake drive 2 Hydraulic header drive with mechanic transmission 3 Electric header drive A08-13 (12)
Efficiency Benefits of the electric driveline 0.32 Wirkungsgradvorteil Advantages in percentage in Prozentpunkten points 1700 1650 1600 1550 1500 0.27 0.22 0.17 Drehzahl Dieselmotor 0.30 0.20 0.10 50 75 100 1800 1/min Difference in energy Wirkungsgradvorteil efficiency % 140 0.12 Theoretical cutting length: 8 mm Rel. Lastmoment A08-13 (13)
Energy efficiency during typical load cycles 1,0 Energy efficiency Wirkungsgrad 0,9 0,8 0,7 0,6 0,5 0,4 0,3 0,2 0,1 3 4 1 2 0,0 20 40 60 80 100 120 140 160 180 200 Nm 220 Torque load Drehmoment 1 Electric driveline 2 3 Hydraulic Non-load operation 4 Non-load operation driveline electric driveline hydraulic driveline A08-13 (14)
Power-to-weight ratio of modules and drivelines - Obvious disadvantages at the electric module drives: Averaged electric drives 3 times heavier than hydraulic ones - New approches enable advantages for the driveline at a glance : elelctric header drive: hydraulic-mechanic header drive: 11.3 kg/kw 15.9 kg/kw - the powertrain for header and intake at a glance: diesel-electric approach: 689.6 kg 17.2 kg/kw hydraulic approach: 565.6 kg 14.1 kg/kw But: comparability of the used systems is limited => Series Production vs. Prototype A08-13 (15)
Size and Power Density of electric motors (by HARMS) Hydraulic Motor (Series production) 7.6 dm³ 3.566 kw/dm³ Electric Motor (Prototype) 29.6 dm³ 0.916 kw/dm³ A08-13 (16)
Costs of acquisition 50 Thousand 45 Acquisition costs 40 35 30 25 20 Electric Motor Safety Concept Cooling Systemn Power Transmission Mountings Electric Driveline Series Hydraulic Driveline Series 15 10 5 0 *) estimated Electric Prototype Electric Series Production Hydraulic Series Production A08-13 (17)
25 20 15 10 5 0 (Careful) Costs of Operation 25 Thousand 20 d Fuel costs: 1.30 /l 15 1.90 /l Fixed capital 10 6.94 /l 4.75 /l Costs hydraulic oil: 5 0 0 1 2 3 4 5 6 7 8 9a 10 Useful life A08-13 (18)
Summary Advantages of the diesel-electric driveline: Closed loop control of the drives and feedback of the process parameters enables easy integration into driveline managements system Efficiency benefits at a wide range of the operation map of about 16 percentage points (between 13.5 to 30 percentage points) Efficiency benefits during typical load cycles between 14 to 20 percentage points Disadvantages of the diesel-electric driveline Power-to-weight ratio of the total driveline is about 22 % higher Power Density is about 3.9 times inferior Amortization or increased acquisition costs after the total useful life A08-13 (19)
The future power train design in mobile working machines? Decentralized unit including power electronics and motor - electric drive unit (EDU) - Example: Combine harvester Electrical Storage device Grain tank distribution Accelerator drive unit drum Straw chopper Spreader Control System EDU EDU Straw walker Fuel Cell EDU EDU EDU Sieve Cutter bar Feeder fan Conveyer roller Synchronic drive Threshing drive unit drum Suction fan power electronics EDU EDU EDU EDU Cleaning Fan rethresher auger drive unit Grain auger motor motor power BUS Integrated EDU Centralized power electronics Decentralized motors Control BUS Central EDU for modules with comparable requirements A08-13 (20)
Conclusions Diesel-electric drivelines are an additional alternative in mobile working machines show high efficiency even under low work load improve control and adjustment have highest benefit in systems with very large variable requirements allow direct use of electricity from solar and fuel cells Thank you for your attention! (michael.gallmeier@wzw.tum.de) A08-13 (21)