Electric and Hybrid vehicles


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Different types and classifications of EHV

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Electric and Hybrid vehicles

  1. 1. K C Karthik 2nd sem, M.Tech(A.E)
  2. 2. Need Electric and Hybrid vehicles  Over dependence on petrol/diesel  Rising petrol/diesel prices  Pollution and the resultant global warming  Noise in conventional vehicles  Need for alternate power sources  Need for Eco friendly vehicles  EV, HEV - The solution?
  3. 3. Electric vehicles  An Electric vehicle is an automobile that is propelled by one or more electric motors, using electrical energy stored in energy storage device.  The primary components are motor, controller, power source, and transmission.
  4. 4. Block diagram An Electric vehicle system
  5. 5. Advantages  No Gas Required  No Emissions  Cost Effective  Low Maintenance  Pay back period  Low noise
  6. 6. Disadvantages  High Initial Cost- Many times that of conventional vehicles  Short Driving Range- Range anxiety  Recharging takes much longer time than refueling gasoline- lack of charging infrastructure  Battery pack takes space and weight of the vehicle which otherwise is available to the people
  7. 7. Concept of hybridization  Multiple sources of power  Making ICE work in most efficient range  Sizing of motor and ICE lower compared to conventional vehicles and EV
  8. 8. Hybrid Vehicles  The term hybrid vehicles in general usage refer to vehicles with two or three different type of sources delivering power to the wheels for propulsion.  The most common hybrid vehicles have an IC engine and one or more electric machines for vehicle propulsion.  The IC engine can be used to generate electric energy ‘on board’ to power the machines.
  9. 9. Classification  Based on the path of energy flow  Mechanical power transmission path (MPTP)  Electrical power transmission path (EPTP)  Combination of MPTP and EPTP  Based on architecture  Series  Parallel  Series-Parallel
  10. 10. Classification  Based on degree of hybridization  Mild  Power  Energy  Charge depleting  Charge sustaining
  11. 11. Mechanical power transmission path (MPTP)  The primary powertrain components in a conventional ICE vehicle are engine and transmission. The energy flow in a vehicle starts from source of energy and ends at wheels with the delivery of propulsion power known as power transmission. Power transmission path in conventional IC engine
  12. 12. Electrical power transmission path (EPTP)  In electric vehicle power transmission is almost electrical except for coupling devices between electric propulsion motor and wheels. The coupling device can simply be a gear to match electric machine speeds to vehicle speeds. Power transmission path in an electric vehicle
  13. 13. Combination of MPTP and EPTP  The propulsion power is transmitted to wheels through either MPTP or EPTP or combination of both.  The MPTP is associated with an IC engine and transmission, whereas EPTP consists of energy storage system, a generator, propulsion motor and transmission.
  14. 14. Block diagram A hybrid electric vehicle powertrain
  15. 15. Series HEV  A series hybrid is one in which only one energy converter can provide propulsion power.  Only electric motor provides all propulsion power to wheels.  A downsized IC engine drives a generator, which supplements batteries and can charge them when it fall below certain charge level.  The drawback is size of traction motor, which as to be rated for max. power requirement of vehicle.
  16. 16. Block diagram Series HEV powertrain
  17. 17. Advantages  Flexibility of location of engine-generator set  Simplicity of Drive train  Suitable for short trips with stop and go traffic Disadvantages  It needs IC engine, generator and motor  Motor must be designed for maximum sustained power that vehicle require such as climbing a high gradient  All drivetrain components need to be sized for maximum power for long distance, high speed driving
  18. 18. Parallel HEV  A parallel hybrid is one in which more than one energy conversion device can deliver propulsion power to the wheels.  The IC engine and electric motor are configured in parallel with a mechanical coupling.  The power requirements of electric motor is lower than that of series HEV.
  19. 19. Block diagram Parallel HEV powertrain
  20. 20. Advantages  It needs only IC engine and motor/generator  A smaller engine and motor can be used to get same performance, until batteries are depleted Disadvantages  The control complexity increases, since power flow has to be regulated and blended from two parallel sources  The power blending from IC engine and motor needs a complex mechanical device
  21. 21. Series-Parallel HEV  It combines the benefits of series and parallel architecture with charge sustaining capability.  The power-split device divides the output from the engine into mechanical and electrical transmission paths.  Even IC engine is also used to charge the battery.  They are capable of providing continuous high output power compared to series or parallel powertrain.
  22. 22. Block diagram Series –Parallel combination HEV
  23. 23. Drive Modes of Operation
  24. 24. Torque characteristics Electric motor and IC engine torque characteristics
  25. 25. Torque characteristics  The torque characteristic of a motor is shown along with torque characteristics of IC engine.  For electric motor, a high torque is available at starting, which is the rated torque of motor.  The peak or rated power from a motor is obtained at base speed (w b) when motor characteristics enter the constant power region from constant torque region once voltage limit of power supply is reached.  The motor rated speed (w rated) is at end of the constant power region. The IC engine peak power and torque occur at the same speed.
  26. 26. Modes of operation-TOYOTA Prius
  27. 27. Commercial vehicles  Toyota Prius  Toyota Highlander  Ford Escape  Mercury Mariner  Honda Insight  Honda Civic HEV  Honda Accord HEV
  28. 28. Challenges  Time of battery changing is long  Batteries are heavy (100kg extra weight consumes 2L/100km more)  Batteries are expensive  Low performance in hot or cold temperatures also may damage the battery  Very sensitive to overcharge/undercharge(Battery life reduces dramatically)  Contain toxic heavy metals, disposal issue
  29. 29. Advantages of a Hybrid Car  Environment friendly  Financial benefits  Less dependence on fossil fuels  Regenerative braking system  Built from lighter materials
  30. 30. Disadvantages of a Hybrid car  Less power  Expensive  Poor handling  Higher maintenance cost
  31. 31. Conclusion  Using the concept of Hybridization of cars results in better efficiency and also saves a lot of fuel in today’s fuel deficit world.  A hybrid gives a solution to all the problems to some extent.  One can surely conclude that this concept will follow with even better efficiency & conservation rate