Prius

The Toyota Prius is one of the world's first commercially mass-produced and marketed hybrid automobiles. Manufactured by Toyota, the Prius first went on sale in Japan in 1997, and was introduced to the worldwide market in 2000. more...

By the end of 2003, nearly 160,000 units had been produced for sale in Japan, Europe, and North America. In Latin, prius means "before" or "first". The Prius (2000 to 2003 model years) is certified as a Super Ultra Low Emission Vehicle (SULEV) by the California Air Resources Board (CARB). With the 2004 model, the Prius was redesigned as a midsize hatchback, and certified as an Advanced Technology Partial Zero Emission Vehicle (AT-PZEV).

In 2005, the car was voted European Car of the Year, after the fuel-sipping sedan picked up the corresponding Motor Trend Car of the Year title for 2004. The Prius also won the North American Car of the Year award for 2004 and was nominated in 2001.

How it works

The Prius has been called a true hybrid vehicle, designed from the bottom up. Toyota's goal for the Prius was to reduce the amount of pollutants it produced and to be as energy-efficient as possible. They used several methods to try to achieve this goal, including:

1. More efficient use of the internal combustion engine (ICE), reducing gasoline consumption. The 1NZ-FXE engine uses the more efficient Atkinson cycle instead of the more common Otto cycle;
2. Two electric motor/generators, providing 50 kW (67 hp) @ 1,200 to 1,540 rpm and 400 N·m (295 ft·lbf) torque from 0 to 1,200 rpm, which significantly contribute to performance & economy;
3. 50 kW IGBT inverter controlled by a 32 bit microprocessor, which efficiently converts power between the batteries and the motor/generators.
4. Lower coefficient of drag at 0.26 (0.29 for 2000 model), reducing air resistance especially at higher speeds;
5. Lower rolling-resistance tires on the 2000 model, reducing road friction;
6. Regenerative braking, a process for recovering kinetic energy when braking or traveling down a slope and storing it as electrical energy in the traction battery for later use while reducing wear and tear on the brake pads;
7. Sealed 168 cell nickel metal hydride (NiMH) battery providing 201.6 volts;
8. Continuously variable transmission — the Prius does not use a typical CVT; Toyota calls it the Power Split Device. The electric motors and gas engine are connected to a planetary gear set which is always engaged, and there is no shifting.
9. Flexible resin gas tank, reducing the amount of hydrocarbon emissions in the form of escaped gasoline vapor;
10. Vacuum flask coolant storage system that stores hot engine coolant, then reuses it to reduce warm-up time.
11. Weight reduction — for example the hatch and hood are made of aluminium instead of steel.

Touted advantages of the Prius over previous energy-efficient designs include never needing to be plugged in, as all energy ultimately comes from the gasoline engine. This means it drives like a traditional ICE automobile, with the onboard computer taking care of shifting power to and from the engine and motors, and automatically determining when to charge the battery, as well as the most efficient use of the engine or the electric motors (or both) based on driving conditions. This also means that one cannot use electricity from external sources; some consider this to be a serious disadvantage. The Prius recovers energy that would be otherwise wasted: when braking, the car's kinetic energy is partly recovered to recharge the battery instead of being wasted as heat. This also reduces brake wear.

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