Hybrid vehicles

Technology

A hybrid car refers to a vehicle that uses both a fuel powered engine and an electric motor with a rechargeable system (batteries or maybe in future solar fuel cells) for propulsion. Hybrids cars, unlike pure electric vehicles that need to be plugged in to the electricity grid, recharge their batteries on the road (using the combustion engine to generate energy and capturing energy from braking).

Hybrid cars are one solution for lowering fuel consumption and reducing oil dependence. 4.7-5.1 l/100 km (51-60 MPG) is a typical consumption for the Toyota Prius, lowering to 3.2 l/100 km for the experimental tiny Smart Forfour Hybrid, and zero if we consider the rechargeable technology by fuel engine. This is compared to an average 6.5 l/100 km for European vehicles and 9.6 l/100 km for American ones (source World Energy Council 2006).

Despite these benefits, sales of hybrid vehicles still represent a small fraction of the car market (1.5% of the world sales, 250,000 vehicles sold in U.S in 2006). Sales aren’t growing as expected due to the limited number of vehicles available (only about 10 models are proposed yet, a few more in the US) and cost (first base price: $22,000).

Future

Latest developments include regenerative braking, a system that recaptures energy normally wasted in braking and slowing, and enhanced batteries based on Lithium-Ion (4 times the energy density of a lead acid battery) to store the recovered power.

All 2007 vehicles also incorporate engine shut-off technology that shuts the engine off while idling to conserve fuel. More advanced systems may propel themselves short distances before restarting the engine, further improving fuel economy.

If you include external charging (electric plug-in for the new Prius, solar panels an so on,) you get an almost perfect car with the role of the fuel tank reduced to backup source (see moteurnature.com).

Left to right

• Venturi Eclectic, presented as the “first autonomous vehicle in history”…
• Automakers are eager to sale their own hybrid model, believing that offering such vehicles demonstrates both social responsibility as well as technical progress.
• The new Toyota Prius 2007, recalled “plugin-hybrid”, as it becomes rechargeable.