A hybrid vehicle is a vehicle that uses two or more distinct power sources to move the vehicle. The term most commonly refers to hybrid electric vehicles which combine an internal combustion engine and one or more electric motors. However other mechanisms to capture and utilize energy are included.
Power sources for hybrid vehicles include:
• Coal, wood or other solid combustibles
• Compressed or liquefied natural gas
• Electricity
• Electromagnetic fields, Radio waves
• Electric vehicle battery
• Human powered e.g. pedaling or rowing
• Hydrogen
• Petrol or Diesel fuel
• Solar
• Wind
The fuel cell hybrid is generally an electric vehicle equipped with a fuel cell. The fuel cells, as well as the electric battery, are both power sources, making the vehicle a hybrid. Fuel cells use hydrogen as a fuel and power the electric battery when it is depleted.The hybrid vehicle typically achieves greater fuel economy and lower emissions than conventional internal combustion engine vehicles (ICEVs), resulting in fewer emissions being generated. These savings are primarily achieved by three elements of a typical hybrid design:
1. Relying on both the engine and the electric motors for peak power needs, resulting in a smaller engine sized more for average usage rather than peak power usage. A smaller engine can have less internal losses and lower weight.
2. Having significant battery storage capacity to store and reuse recaptured energy, especially in stop-and-go traffic typical of the city driving cycle.
3. Recapturing significant amounts of energy during breaking that are normally wasted as heat. This regenerative braking reduces vehicle speed by converting some of its kinetic energy into electricity, depending upon the power rating of the motor/generator;
These features make a hybrid vehicle particularly efficient for city traffic where there are frequent stops, coasting and idling periods. In addition noise emissions are reduced, particularly at idling and low operating speeds, in comparison to conventional engine vehicles. For continuous high speed highway use these features are much less useful in reducing emissions.
Other types of green vehicles include other vehicles that go fully or partly on alternative energy sources than fossil fuel. Another option is to use alternative fuel composition (i.e. biofuels) in conventional fossil fuel-based vehicles, making them go partly on renewable energy sources.
Basically, it’s a normal, fuel efficient car that has two motors – an electric motor and a gasoline powered motor. It also has a special system to capture braking energy to store in an onboard battery.
Specifically, electric motors use no energy during idle – they turn off – and use less than gas motors at low speeds. Gas motors do better at high speeds and can deliver more power for a given motor weight. That means during rush hour stop and go driving, the electric motor works great and, as an added benefit, does not produce any exhaust thus reducing smog levels. At higher speeds – above 40 mph – the gas motor kicks in and gives that peppy feel so many car owners look for when driving on the highway.
Another benefit of having the gas motor is it charges the batteries while it’s running. Many an electric car owner has been stranded just out extension cord range of an outlet. Hybrid owners can forget about this annoyance; the gas motors starts automatically when the battery gets low and proceeds to charge the battery – a hybrid never needs to be plugged into an outlet. Of course, if you forget to fill the tank…. Still, you can carry a gas can a half mile while a tow truck is necessary in a straight electric car.
All this new technology comes at a price: a hybrid car is complex and expensive. It has two motors and all the ancillary systems to manage them plus a heavy battery and a regeneration system used to produce electricity during breaking.
But hybrid cars offer more than just great fuel economy, they offer many green advantages as well. Even a small increase in fuel economy makes a large difference in emissions over the life of the car. Also, in large cities were pollution is at its worst, they make an even larger difference since they produce very little emissions during low speed city driving and the inevitable traffic jams.
While the US has just started producing hybrids, the Japanese are the recognized leaders. Honda and Toyota are the two largest producers with the Insight and Prius. US car makers are well behind. In fact, during recent introduction of a new hybrid by GM – the Mercury Mariner, they admitted they had to license over 20 separate technologies from the Japanese. US car makers still specialize in SUVs and trucks – Ford has even introduced a hybrid version of its popular Escape SUV.
The tax incentive in the U.S. is another powerful motive – it can reduce your cost up to $3,400 depending on the cost of the vehicle. Better act fast, however, to get the model you want: the tax break only applies to the first 60,000 vehicles produced yearly by each manufacturer. Toyota’s Prius, for example, will quickly reach that number of sales before year-end.
Experts think in the end, hybrids are probably a transition technology. Hydrogen or methane fuel cell powered cars are probably the cars of the future. As for the environment, there are many ways to reduce emissions – using public transport, car pooling, riding a bicycle and even walking. Even just buying a smaller, fuel efficient car makes a big difference. So, think about what you are really trying to accomplish before buying a hybrid – don’t just throw your hard earned dollars at new technology for its own sake because it may be fashionably “green”.
http://phys.org
