PHEV Toyota Prius and solar Toyota Highlander: plug-in electric hybrid cars

Toyota has driven to the number one position in worldwide sales with the help of its hybrid vehicles. With its Prius leading the way in hybrid technology and sales, other manufacturers are scrambling to catch up. Toyota, meanwhile is pushing to retain its edge in the “green vehicle” market.

Each Prius generation since the vehicle was introduced in Japan in 1997 has made significant design improvements. Even with revised EPA estimates, the 2008 Prius is the most fuel-efficient car sold in America, with a combined average of 46 mpg. Toyota hopes to push that efficiency to its limit in the coming years.

Toyota is concentrating on new ways to charge the Prius battery. Currently, the Prius battery is recharged by the gas engine. Many early American Prius owners were able to effectively retrofit their vehicles as plug-in electric hybrid (PHEV) prototypes and Toyota is following suit in its research. It hopes to have a PHEV Prius available to consumers in 2010.

To promote the effectiveness of its prototypes, Toyota will provide several PHEV Prius at the North American International Auto Show in Detroit as executive shuttles from the Cobo Center. These vehicles are being used for research and testing as part of Toyota's on-going sustainable mobility development program with the University of California at Irvine's Advanced Power and Energy Program and the University of California at Berkeley's Institute of Transportation Studies.

The PHEVs in Detroit, as with the vehicles at the universities, are early-development prototypes that will be used for evaluation of real-world customer use and acceptance, ride-and-drives by regulatory officials and NGOs, and technical research and development.

"Our goal with these early prototype vehicles is to begin the process of understanding customer wants and needs in order to help determine the optimal balance between electric vehicle miles, charge time, battery size and cost," said Bob Carter, Toyota Division group vice president and general manager.

One of the marketing strategies of the Prius for the American market has been to stress that the car does not need to be plugged in. Because of this marketing strategy, Toyota initially seemed somewhat reluctant to embrace a PHEV approach. The tremendous success of the Prius and the general acceptance of the hybrid vehicle have led Toyota to rethink its strategy. Americans, it seems, are now ready to plug the car in if it means savings at the pump and further reduced emissions.

The prototype PHEV Prius uses a larger battery size to increase power reserves. This means that it will travel faster and farther on a charge. The stronger battery will keep the car running in electric mode more frequently, saving gas. The initial charge from the household current will greatly benefit drivers, especially on shorter trips.

Other improvements in the works for hybrid vehicles include solar panels on the roof and dashboard that will use the sun’s energy to recharge the battery. Solar-hybrid Prius prototypes are out there- you can buy a solar conversion kit for your Prius for approximately $4,500 from Solar Electrical Systems of California, which has sold 130 kits so far. The company estimates fuel savings of 17% - 29% from a standard Prius.

The hybrid technology works well with alternative fuel sources as well. Hydrogen powered Prius cars have been developed. Ten were delivered in November 2007 to Vistorka, a consortium of companies in Iceland. More immediate could be a potential market for diesel and bio-diesel hybrid engines which would combine two “green” systems for efficiency and environmental friendliness. Add the solar kit and watch Exxon twitch!

One proposed Toyota upgrade that has been delayed is a plan to switch from the current nickel-metal hydride (NiMH) battery to a lithium-ion battery. In February, 2007, Toyota CEO Katsuaki Watanabe said that Toyota was, "aiming at reducing, by half, both size and cost of the third-generation hybrid system.” However, though lithium-ion batteries have a higher energy capacity-to-weight ratio, they cost more and operate at higher temperatures, raising safety concerns.

Given its commercial success, it is no surprise that further advancement of hybrid technology is a top priority for Toyota. In May 2007, cumulative sales of Toyota hybrid vehicles worldwide topped the one million mark, a global sales target the company hopes to hit annually in the early 2010s.

In fact, by the end of calendar-year 2007, the U.S. market has accounted for nearly 750,000 combined Toyota and Lexus hybrid sales, out of the approximately 1.25 million hybrid vehicles sold globally, since the first generation Prius was introduced in Japan in 1997. Toyota estimates that the cumulative reduction in CO2 emissions by these vehicles now totals more than five million tons.

It’s no surprise that hybrid technology research, as one Toyota spokesman described it, "is broad-reaching and being carried out from various angles." With more and more hybrids on the road, I’ll leave you with a sentiment from HybridCars.com, “What are you going to tell your grandchildren you drove in 2007?”