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…

Anatomy of an Artificial Horse for Busy Roads ???

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

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

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

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

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.

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

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%

Another Major Suitability Characteristic of Resource to Vehicle

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

Resistance & Power Requirement at Wheels : City Driving

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.

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.

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

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

Tractive effort and power versus vehicle speed with different Motors

Performance of A Traction Motor

Proposed configurations for an Electric Vehicle