1. November 13, 2008 Heavy Duty Hybrid Truck 1 DEVELOPMENT OF A HYBRID ELECTRIC HEAVY DUTY TRUCK Kemal Çalışkan Prof. Dr. Y. Samim Ünlüsoy Varlık Kılıç Dr. Murat Yıldırım Middle East Technical University FORD OTOSAN

2. November 13, 2008 Heavy Duty Hybrid Truck 2 HYBRID TRUCKS  In recent years, heavy commercial vehicles are equipped with engines of ever increasing power.  As an alternative of replacing the engine with a larger one, vehicle performance can also be improved by hybridization.

3. November 13, 2008 Heavy Duty Hybrid Truck 3 HYBRID TRUCKS  Heavy commercial vehicles are driven for very long distances during their operational lives and account for a significant portion of the overall fuel consumption.  Possible reduction of fuel consumption and emissions for these vehicles by the application of hybrid electric propulsion systems will be significant.

4. November 13, 2008 Heavy Duty Hybrid Truck 4 HYBRID TRUCKS  As opposed to the common objective of reduced fuel consumption and emissions by hybridization; this study presents an application in which performance improvement is the main objective, with the associated improvement in fuel consumption and emissions as a secondary benefit.

5. November 13, 2008 Heavy Duty Hybrid Truck 5 HYBRID TRUCKS  Some of the main truck manufacturer companies have already developed medium sized hybrid trucks and they are working on the development of heavy duty hybrid trucks.

6. November 13, 2008 6Heavy Duty Hybrid Truck HYBRID TRUCKS MACK Class 8 2005 US AirForce Prototype 80kW EM DAF / EATON Class 8 44kW EM Release 2009 Li-Ion Battery System VOLVO Class 8 Job#1 2009 120kW EM NiMH PACCAR/AZURE Class 7 2 prototypes 7.2L diesel 90kW EM UCAP

7. November 13, 2008 Heavy Duty Hybrid Truck 7 OBJECTIVES  Main objective :  to obtain the performance of a heavy truck equipped with a - 12.5 liter diesel engine of 500 PS rated power, power, from a hybrid configuration of a - 9 liter diesel engine with 400 PS rated power and a suitably sized electric motor. power and a suitably sized electric motor.  Secondary objectives : Reduced fuel consumption and emissions.

8. November 13, 2008 Heavy Duty Hybrid Truck 8 TARGET VEHICLE  4x2 Tractor  40 ton Loaded  9 liter 400 PS Diesel Engine  16 Gear Manual Transmission

9. November 13, 2008 Heavy Duty Hybrid Truck 9 PRELIMINARY ANALYSIS  Examine and compare the performance of basic hybrid configurations.  Determine the basic specifications of the electric motor and the battery for the different hybrid configurations to satisfy the performance objectives.  Determine the performance and fuel consumption for different configurations using standard truck driving cycles.

10. November 13, 2008 Heavy Duty Hybrid Truck 10 PRELIMINARY ANALYSIS  For the preliminary simulations of hybrid configurations, NREL’s publicly available vehicle simulation tool, ADVISOR software is used, after being corrected and modified for heavy commercial vehicle analysis: - Converted to rear wheel drive. - Trailer hinge loads are included. - Different hybrid configurations. - Some errors were discovered and corrected.  Component data were confined to those available in the data files of ADVISOR.

11. November 13, 2008 Heavy Duty Hybrid Truck 11  Simulation studies indicated that an EM which is capable of producing of at least: 400 Nm torque @ 1600 rpm, and 70-80 kW power in the speed range from 1000 to 2200 rpm must be specified.  The EM is to be a shaft motor with a shaft torque capacity of at least 2000 Nm. PRELIMINARY ANALYSIS

12. November 13, 2008 12Heavy Duty Hybrid Truck  It was found that a battery group of : - 90Ah capacity at 360V - operated within 20% state of charge (SOC) level (e.g. max charge (SOC) level (e.g. max 70% - min 50%) 70% - min 50%) can feed the electric motor at full power for five minutes. PRELIMINARY ANALYSIS

13. November 13, 2008 Heavy Duty Hybrid Truck 13  Fuel consumptions of the conventional and hybrid configurations on a number of drive cycles showed that 10-50 % reduction in fuel consumption, compared to 12.5 liter, can be realized depending on the cycle of interest.  The highest reduction in fuel consumption is obtained in the cycles which represent low speed profile with considerable idling periods. PRELIMINARY ANALYSIS

14. November 13, 2008 14Heavy Duty Hybrid Truck SELECTION OF HYBRID COMPONENTS  The required electric motor specifications are satisfied by a 100 kW rated power (continuous) EM.  The required battery specifications are satisfied by the custom designed battery pack containing 200 units (100 Series 2 Parallel) of 45Ah Li-Ion cells. The total capacity 32.4 kWh and nominal operating voltage is 360V.

15. November 13, 2008 Heavy Duty Hybrid Truck 15 Possible Hybrid Configurations

16. November 13, 2008 Heavy Duty Hybrid Truck 16 Selection of Configuration  Operation of the hybrid vehicle should be as similar to the conventional vehicle as possible.  Selection of a certain configuration may be dictated by the packaging requirements for the particular vehicle to be hybridized.  Minimum change in the original vehicle configuration is desired.

17. November 13, 2008 Heavy Duty Hybrid Truck 17 Selection of Configuration In view of the above criteria, it is decided to carry out detailed acceleration, gradeability and fuel consumption simulations for the three candidate hybrid configurations.  Parallel hybrid driveline with electric motor located: - after clutch, - before clutch, and - after transmission.

18. November 13, 2008 Heavy Duty Hybrid Truck 18 Selection of Configuration  After the results of the simulation studies are obtained, the simulated performance of each hybrid driveline configuration is compared with those of: - conventional with 9 lt, and - conventional 12.5 lt engines.

19. November 13, 2008 19Heavy Duty Hybrid Truck ACCELERATION PERFORMANCE Order of Merit 5 3 1 1 4

20. November 13, 2008 20Heavy Duty Hybrid Truck GRADEABILITY [%] Order of Merit 5 1 1 1 4

21. November 13, 2008 21Heavy Duty Hybrid Truck FUEL CONSUMPTION [lt/100km] NYGTCWUINTERUDDSFDV Reference

22. November 13, 2008 22Heavy Duty Hybrid Truck Comparison of the Hybrid Configurations

23. November 13, 2008 Heavy Duty Hybrid Truck 23  The two choices, after-clutch and pre- clutch, do not have any clear advantages over each other with respect to performance, fuel consumption, and required driveline modifications.  Before clutch configuration lacks the ability of pure electric drive while the after clutch configuration have problems with idle charging and using EM as the starter. Selection of Configuration

24. November 13, 2008 24Heavy Duty Hybrid Truck Selection of Configuration  It is decided to employ the “Double Clutch Parallel Hybrid” configuration. This configuration will include both the before clutch and after clutch configurations.  It will thus be possible to observe advantages and disadvantages of both configurations by disabling one of the clutches at a time.

25. November 13, 2008 25Heavy Duty Hybrid Truck PACKAGING

26. November 13, 2008 Heavy Duty Hybrid Truck 26 CHASIS MODIFICATIONS  Engine mounts and locations  Fuel tank position and mounts  Li-Ion battery pack mounts  Electric motor housing and mounts  Propeller shaft  Rear splash shield brackets  Brake Pedal Sensor  Electric motor cooling pump, radiator and hoses  Clutch control system pipes  HV Cabling  Gear shifting cables  Brake pipes  Fuel pipes

27. November 13, 2008 27Heavy Duty Hybrid Truck BRAKING SYTEM  To satisfy the legal requirements for braking of commercial vehicles a secondary braking system is necessary.  The large and heavy retarder of the vehicle is to be replaced with a smaller and lighter intarder coupled to the transmission.

28. November 13, 2008 28Heavy Duty Hybrid Truck BRAKING SYTEM  However, if - EM size is doubled, and - power resistors are used to dissipate the energy when the dissipate the energy when the batteries are full batteries are full there will be no need for the intarder !

29. November 13, 2008 29Heavy Duty Hybrid Truck CONTROL SYSTEM DEVELOPMENT A forward looking simulation model is developed in Matlab/Simulink, including external and internal motion resistances, load transfer due to trailer loads, detailed clutch and tire models. A forward looking simulation model is developed in Matlab/Simulink, including external and internal motion resistances, load transfer due to trailer loads, detailed clutch and tire models.

30. November 13, 2008 30Heavy Duty Hybrid Truck CONTROL SYSTEM DEVELOPMENT  The forward looking simulation model for the vehicle performance accepts the following commands: - gas pedal position, - brake pedal position, - intarder level, - pure electric drive switch state, - idle charging switch state.  These commands can be directly input or may be determined by a driver model to let the vehicle trace a cycle velocity profile.

31. November 13, 2008 31Heavy Duty Hybrid Truck CONTROL SYSTEM DEVELOPMENT  Modes of the rule based control algorithm:  EM only drive (engine disengaged) - engine runs inefficiently at very low power, - launch up to a certain speed.  Engine only drive (EM freewheeling) - engine runs efficiently.  Engine+EM drive (power summation) - power demand is more than engine capacity.  Engine+EM drive (power split) - engine runs inefficiently at high power.

32. November 13, 2008 32Heavy Duty Hybrid Truck CONTROL SYSTEM DEVELOPMENT   Modes of the rule based control algorithm:  Engine drive + EM charging - engine runs inefficiently at low power.  Regeneration - friction and intarder braking, - engine braking for zero throttle.  Pure electric drive (if requested by the driver)  Idle charging (if requested by the driver) ! The selection and application of the control rules depend on the battery state of charge (SOC).

33. November 13, 2008 33Heavy Duty Hybrid Truck CONTROL SYSTEM DEVELOPMENT

34. November 13, 2008 34Heavy Duty Hybrid Truck CONCLUSIONS Difficulty in finding suitably sized hybrid components. Difficulty in finding suitably sized hybrid components. Difficulty (in terms of time and cost) in purchasing these components. Difficulty (in terms of time and cost) in purchasing these components. The current battery technology is still the most challenging obstacle for the development of heavy duty hybrid vehicles due to their weight, volume, and cost. The current battery technology is still the most challenging obstacle for the development of heavy duty hybrid vehicles due to their weight, volume, and cost.

35. November 13, 2008 35Heavy Duty Hybrid Truck CONCLUSIONS  With the conclusion of the project study, a prototype hybrid truck will be available for further development by road tests and studies on the control strategies.  The study may be extended for: -engine shutdown capability. -removal of intarder, starter and alternator. -adaptation to the anti-idling and reduced emission laws. -application to trucks of different classes. classes.

36. November 13, 2008 36Heavy Duty Hybrid Truck THE END

37. November 13, 2008 37Heavy Duty Hybrid Truck HYBRID TRUCKS

38. November 13, 2008 38Heavy Duty Hybrid Truck  It was found that a battery group of 90Ah capacity at 360V operated within 20% state of charge (SOC) level (e.g. max 70% - min 50% SOC) can feed the electric motor at full power for five minutes. PRELIMINARY ANALYSIS

39. November 13, 2008 39Heavy Duty Hybrid Truck BRAKING SYTEM  Legal requirement for braking of commercial vehicles is stated as : maintaining the speed of 30 km/h on a 7% down gradient for a distance of 6 km without using the friction brakes.  Therefore, a secondary system is necessary to fulfill the legal requirement.