In 1997 the Japanese Toyota Motor Corporation introduced the hybrid-electric Prius. Toyota made improvements on the original model and released the Prius on the global market in 2001. Utilizing the U.S. Environmental Protection Agency’s (EPA) rating system, the Prius is the most economically efficient car to be marketed in the United States. It has also won awards worldwide for carbon dioxide ratings. [2] The Prius is what is known as a series-parallel configuration hybrid. In a nutshell this means that the car can run solely on the battery, the engine, or a combination of the two. The batteries are charged by the petrol (gas) engine directly or by regenerative braking, unlike other plug-in hybrid prototypes. The braking recovers kinetic energy when traveling downhill and stores it in the battery for later use. The inverter is controlled by a 32-bit microprocessor that transfers power between the batteries and the generators. The Prius incorporates what Toyota calls a Power Split Device. It uses a computer operated transmission (Continuously Variable Transmission) which allows the electric and gas engines to be connected through one gear set. This gear set is constantly engaged with no shifting. [3] This transmission ensures that the Prius is running under the most environmentally friendly and economically sound conditions.

In addition to the fuel efficiency, the Prius is also a crusader for the environment. There are a few features which reduce the level of pollutants being released into the air. The gas tank is not made in the traditional way. It is instead made of a flexible resin which allows for a reduction in hydrocarbon emissions in the form of escaped gasoline vapors. It also has a feature which stores hot engine coolant when the car is turned off. This vacuum flask coolant storage system then reuses the coolant to reduce warm up time. The Prius also stops the combustion engine instead of idling which reduces exhaust gases and is therefore better for the catalytic converter as well. Once the engine has warmed up and the catalytic converter has reached operating temperature, the engine can shut down. Therefore under low energy loads the electric power takes over totally. Toyota refers to this as something called “stealth mode” because the engine is so quiet. [4] The quietness of the engine also helps to reduce noise pollution when driving through a residential area late at night. The engine will eventually restart automatically when more power or torque is needed. This will occur during periods such as climbing up a hill or slope. Therefore when driving in the city, or outside of suburban terrain, the Prius is most advantageous. Due to this fact it is even more important to note that the Prius is 90% cleaner than conventional gasoline-only vehicles. It has been classified as a Super Ultra Low Emissions Vehicle, and has a special certification from the California Air Resources Board. [5] So if you live in the deteriorating conditions of the bigger, more populated cities, buying a Prius is doing a favor to the air that you breathe.

Some other cool facts about the Toyota Prius include its safety features. It scored a 5-star driver and 4-star passenger frontal collision rating and a 4-star side crash rating by the NHTSA. It also scored 4 stars in rollover testing. Features such as lower-rolling resistance tires reduce road frictions. Lower coefficient of drag also reduces air resistance when the car is traveling at higher speeds. Uncle Sam has even been known to give buyers of the Prius a tax advantage that is worth it for consumers to inquire more about. [6] If you are wondering what the next step in the evolution of the Prius will be, think plug-in. Plug-in hybrids utilize a much larger battery pack that is externally recharged, unlike the internal recharging of the present day Prius. There are talks within Toyota about a possible Lexus brand plug-in hybrid slated for release in 2009. This will allow for even less fuel consumption with an even larger engine. [7] Then eventually down the line in the not so distant future, every vehicle released with a Toyota brand, or any brand for that matter, may be hybrid capable or convertible. As I discussed earlier, there are limitless possibilities in the broader spectrum. After all, Toyota executives had initial concerns that they would not sell enough hybrids in order for it to be a profitable proposition. In June of 2007, ten years after the Prius was introduced, they announced net sales of 1 million hybrid vehicles globally, 757,600 of those being a Prius. [8]