Tuesday, May 10, 2011
Hybrid electric-petroleum vehicles
When the term hybrid vehicle is used, it most often refers to a Hybrid electric vehicle. These encompass such vehicles as the AHS2 (Chevrolet Tahoe, GMC Yukon, Chevrolet Silverado, Cadillac Escalade, and the Saturn Vue), Toyota Prius, Toyota Camry Hybrid, Ford Escape Hybrid, Toyota Highlander Hybrid, Honda Insight, Honda Civic Hybrid Lexus RX 400h and 450h and others. A petroleum-electric hybrid most commonly uses internal combustion engines (generally gasoline or Diesel engines, powered by a variety of fuels) and electric batteries to power the vehicle. There are many types of petroleum-electric hybrid drivetrains, from Full hybrid to Mild hybrid, which offer varying advantages and disadvantages.[21]
Ferdinand Porsche in 1900 developed the first gasoline-electric series-hybrid automobile in the world, setting speed records using two motor-in-wheel-hub arrangements with a combustion generator set providing the electric power. While liquid fuel/electric hybrids date back to the late 19th century, the braking regenerative hybrid was invented by David Arthurs, an electrical engineer from Springdale, Arkansas in 1978–79. His home-converted Opel GT was reported to return as much as 75MPG with plans still sold to this original design, and the "Mother Earth News" modified version on their website.[22]
The plug-in-electric-vehicle (PEV) is becoming more and more common. It has the range needed in locations where there are wide gaps with no services. The batteries can be plugged in to house (mains) electricity for charging, as well being charged while the engine is running.
Heavy vehicles
Hybrid power trains use diesel-electric or turbo-electric to power railway locomotives, buses, heavy goods vehicles, mobile hydraulic machinery, and ships. Typically some form of heat engine (usually diesel) drives an electric generator or hydraulic pump which powers one or more electric or hydraulic motors. There are advantages in distributing power through wires or pipes rather than mechanical elements especially when multiple drives—e.g. driven wheels or propellers—are required. There is power lost in the double conversion from typically diesel fuel to electricity to power an electric or hydraulic motor. With large vehicles the advantages often outweigh the disadvantages especially as the conversion losses typically decrease with size. With the exception of non nuclear submarines, presently there is no or relatively little secondary energy storage capacity on most heavy vehicles, e.g. auxiliary batteries and hydraulic accumulators—this is changing.
How often do hybrid batteries need replacing? Is replacement expensive and disposal an environmental problem?
The hybrid battery packs are designed to last for the lifetime of the vehicle, somewhere between 150,000 and 200,000 miles, probably a whole lot longer. The warranty covers the batteries for between eight and 10 years, depending on the carmaker and the location.
Battery toxicity is a concern, although today's hybrids use NiMH batteries, not the environmentally problematic rechargeable nickel cadmium. "Nickel metal hydride batteries are benign. They can be fully recycled," says Ron Cogan, editor of the Green Car Journal. Toyota and Honda say that they will recycle dead batteries and that disposal will pose no toxic hazards.There's no definitive word on replacement costs because they are almost never replaced. We have seen anecdotal reports of total battery replacements costing about $3,000.
Can you tow with a hybrid?
Towing a Toyota Prius or Honda requires front wheels off the ground. Honda’s (manual transmission) can be towed with wheels on the ground, but it’s not recommended. Honda’s with CVT can be towed with wheels off the ground. Tow dollies are commonly used.
Toyota and Honda will say not to tow anything behind their hybrids. Except for the Insight, which has an aluminum frame, it’s done everyday. Prius and Civic Hybrid can tow with a tongue weight of less than 100 lbs and total trailer under 1000 lbs. (Just basic guidance; be careful.)General Motors Two-Mode Hybrids, like the Chevy Tahoe, are specifically designed for full towing capabilities. Other SUV hybrids have adequate towing power. For example, the Ford Escape Hybrid and Lexus RX 400h have towing capacities of 1,000 pounds and 3,500 pounds respectively.
Chevrolet Silverado
While some treehuggers put fuel economy above all other considerations, many trades people, commercial users, farmers and ranchers absolutely require the capabilities of a pickup truck. The Silverado Hybrid (and the similar Sierra Hybrid) are still the only gas-electric pick-ups on the market. For 2011, Chevrolet continues to offer the Silverado Hybrid in just one body style, a four-door crew cab with a short box. There are two trim levels, 1HY and 2HY, and a choice of either two- or four-wheel drive. The only change is an upgrade to GM’s OnStar 9.0 telematics system that the automaker says provides improved voice recognition.
Nissan Sentra
Nissan’s green PR is all about the electric LEAF, but at half the sticker price and 34 mpg on the highway, the Sentra deserves a look from the ultra-pragmatist. New Sentra models come with one engine, a 2.0-liter four cylinder, and two transmission options, a six-speed manual and a continuously variable transmission (CVT). The fuel-miser of the group is the CVT, and yes, today’s automatic transmissions often deliver better fuel economy than their manual cousins. With this combination, the Sentra achieves an EPA estimate of 27 city/34 highway and a combined 30 mpg. With the six-speed manual, the 2.0-liter engine dispenses 24 city/31 highway and 27 mpg combined.
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