1. Electric Motors as Automotive Prime Movers
P M V Subbarao
Professor
Mechanical Engineering Department
Eliminate Digestion System in an Artificial Horse to Mimic a Horse…

2. Anatomy of an Artificial Horse for Busy Roads ???

3. Vehicle speed and acceleration/deceleration in an FTP urban drive cycle

4. Energy Loss : Urban Driving : 3000 CC Engine Vehicle
Standby 8%
Aero 3%
Fuel Tank
100%
16%
13%
Engine
Driveline
Rolling 4%
Braking 6%
Driveline
Losses 3%
Engine Loss
76%
POWERTRAIN
VEHICLE-Related

5. Energy Loss : Highway Driving : 300 CC Engine Vehicle
Standby 0%
Aero
10%
Fuel Tank:
100%
23%
19%
Engine
Driveline
Rolling 7%
Braking 2%
Driveline
Losses 4%
Engine Loss
77%
POWERTRAIN
VEHICLE-Related

6. Low Irreversibility Prime Movers
Combustion Engines
Battery Electric
Fuel
Transmission
Engine
Battery
Transmission
Motor/ Generator

7. The Importance of Electric Vehicles:
Electricity can become is cheaper than fuel.
Electricity can come from renewable resources such as solar and wind power.
Electric cars pollute less than gas-powered cars.
Electric cars may require less maintenance than fuel-powered cars.
You don't even need to get your oil changed every 5,000 km!
By using domestically-generated electricity rather than relying on foreign oil, A country can become more independent.

8. Energy Loss : City Driving – Electric Vehicle
Aero
29%
Batteries
100%
90%
76%
Motor
Driveline
Rolling
35%
Braking
11%
Driveline
Losses
14%
Motor Loss
10%
POWERTRAIN
VEHICLE-Related

9. Mine to Wheel Efficiency
Mine-to-Tank
Tank-to-Wheels
31%
23%
Generation
33%
Transmission
94%
Plug-to-Wheels
76%
31%
76%
= 23%
Refining
82%
Transmission
98%
Pump-to-Wheels
16%
13%
80%
80%
16%
= 13%

10. Another Major Suitability Characteristic of Resource to Vehicle

11. Additional Inertial Losses in EVs
Gasoline :1 kg
Batteries
~ 5.4 MJ of Mechanical energy
~1 Li-ion battery (Car battery size)
17.9 kg
2.9 litre

12. Resistance & Power Requirement at Wheels : City Driving

13. Characteristics of A Typical variable-speed electric motor
The range of the constant power operation depends primarily on the particular motor type and its control strategy.

14. Speed Ratio of Typical variable-speed electric motor
At the low-speed region the motor has a constant torque.
The maximum speed at which a motor generates a constant (maximum) torque is known as base speed.
In the high-speed region the motor has a constant (maximum) power.
The highest speed at which the motor generates constant maximum power is known as maximum speed.
This characteristic is usually represented by a speed ratio x, defined as the ratio of its maximum
speed to its base speed.

15. Torque Requirement at Wheels : City Driving : Need for A Gear Box
InstantaneousTractive Effort demanded by a vehicle):

16. Speed ratio & Speed–torque profile of a 60 kW electric motor

17. Tractive effort and power versus vehicle speed with different Motors

18. Performance of A Traction Motor

19. Proposed configurations for an Electric Vehicle