When braking or coasting to a stop, the hybrid uses its electric motor (3) as a generator to produce electricity, which is then stored in its battery pack (6).
Unlike all-electric vehicles, hybrid vehicles do not need to be plugged into an external source of electricity. Gasoline stored in a conventional fuel tank (5) provides all the energy the hybrid vehicle needs.
Picture courtesy of www.fuelecomony.gov
In reality, modern diesels have the edge over such hybrids. More powerful and much cheaper to produce, they are proving to be the most worthwhile ‘alternative fuel’ cars. Although the long term future of the conventional petrol/diesel engine may be bleak, such efficiency of new technology limit their impact on natural resources and the environment until replacement technology can be introduced.
Another route to less emissions is gas. Offered as a factory fit option by Vauxhall (Dualfuel), Volvo (Bi-fuel) and many others, Liquid Petroleum Gas (LPG) is cleaner than petrol, far cheaper and ever easier to obtain. Meanwhile Compressed Natural Gas (CNG), although requiring heavy pressurised storage containers, is not reliant on crude oil, is readily available in the UK, and is again clean and environmentally friendly.
None of these alternatives really solve the problem of reducing fossil fuel stocks, though Bio-Diesels, produced from harvested crops, may ensure that diesel engines outlive their petrol counterparts. To look further ahead we need to take a look in manufacturer’s laboratories – where we’ll almost certainly see the ‘fuel cell’ car under development.
Typified by Toyota’s FCHV-4, they’re powered by Hydrogen. This Hydrogen is passed through a ‘fuel cell’, where it undergoes ‘reverse electrolysis’, combining with oxygen. This process generates electricity, with the only by-product being water. The result? Zero emmisions, no limited range and performance, compared to ordinary cars. Fuel cell cars are twice as efficient as ‘regular cars’ and ever improving packaging means they’re barely any less practical either.
A growing dependence on imported oil, along with a heightened concern about the environment, has led to my increased interest in electric cars as an alternative to traditional gas-powered automobiles. Battery systems for electric vehicles are improving, but with their limited range of travel, they are still not feasible for most people. Newly available automotive technology, are known as hybrid electric vehicles (HEV). Hybrid power systems were conceived as a way to compensate for the shortfall in battery technology. Hybrid electric vehicles recharge as you drive, get approximately double the miles per gallon of gas than current vehicles and can be refueled at any gas station.
Each hybrid vehicle will produce thousands fewer pounds of pollutants than the vehicles currently on the road. According to Department of Energy estimates, a hybrid car driven 12,000 miles per year will cut carbon dioxide emissions by 4,700 pounds over its predecessor, says the National Resources Defense Council article on earth smart cars.(National Resources Defense Council). There are currently two hybrid electric vehicles that will soon be out in the UK, and on the market hopefully in the year 2003. The Honda Insight was the first hybrid electric vehicle to be available for public purchase in the United States. The Honda Insight is a two-seat sporty car that has earned the best EPA mileage rating in history, rated at 61 miles per gallon in the city and 68 miles per gallon on the highway (Honda 6). Because of its size, however, I am not quite sure about the safety and durability of this car. In addition, I believe that people who are looking for a sports car are not the same people who will make environmental and fuel efficiency a priority over looks and power.
The Toyota Prius, on the other hand, is a five-passenger vehicle that equates in size to a Toyota Corolla. The Prius has been sold in Japan since 1997, but has only recently been available in the United States. While the Toyota Prius has a slightly lower EPA mileage rating of 50 miles per gallon in the city and 40 miles per gallon on the highway than the Honda Insight, I believe it is more likely to be widely accepted because it is larger then the Insight and thus more appealing to the environmentally aware family person. Priced at just under 20,000, the Prius is comparable once again to the Toyota Corolla, which puts it within the financial reach of most middle class people. The Prius will comfortably hold a family of five and has the power to perform well in passing and up-hill driving conditions. In the prius there are a number of key safety features such as side-impact door beams, front and rear energy-absorbing crumple zones, standard anti-lock brake system, both driver and passenger air bags, and child-protector rear door locks. In addition, the Prius features a security system and engine immobilizer. Unless the correct key is used, the starter system becomes disables and the car will not start. This anti-theft protection is achieved through a chip embedded into the key using a rolling identification code that cannot be duplicated.
The hybrid engine system of the Prius is a highly efficient gas engine combined with an electronic motor. Depending on the driving conditions, one or both are used to maximize fuel efficiency and minimize emissions. During initial acceleration, the electric motor is the primary source of power. The gas engine is started under heavy acceleration, such as passing or going uphill. During highway driving, the gas engine is the primary source of power with the electric motor assisting as needed to achieve power. When the vehicle is coasting or braking, the electric motor acts as a generator to charge the battery and when the vehicle is stopped, the gas engine shuts off to conserve fuel and eliminate exhaust emissions. The ability of the electric motor to recharge the battery means that the Prius never needs to be externally recharged and has a driving range of between 536 miles on the highway and 619 miles in the city on one tank of gas. The standard display panel allows continuous monitoring of the energy efficiency at work.
The many attractive features of the Prius, (relatively low cost, ultra-low emissions and fuel economy) make this vehicle the only alternative available today that meets my requirements of safety, cost, environmental awareness, comfort, looks and fuel efficiency. I was also impressed with the 8 year or 100,000 mile warranty on the battery pack of the Prius and the three-year/36,000 mile roadside assistance and scheduled maintenance program for Prius owners.
Hydrogen is fuelling BMW’s future plans; however, a different route has been taken. The German giant favours hydrogen-powered combustion engines, just like todays car use, but with one major difference; the only thing coming out of the fuel pipe, as with the fuel cell cars, will be water. This has been made possible by hydrogen’s combustion characteristics, which are not that dissimilar to that of petrol. The main stumbling block is the availability of liquid hydrogen. Its so volatile, it has to be stored very carefully, meaning a huge investment will have to be made before the project is viable.
But so long as hydrogen is produced using ‘renewable’ resources such as wind or solar power, we really will finally have ‘environmentally-neutral’ cars. The car is not dead yet, thanks to the huge efforts manufacturers are putting into developing alternative fuels. As yet we cant be certain which of the above technologies, if indeed any will dominate, but with incresing concern over the limited supply of fossil fuels, and the environment, one thing for certain, the car as we know it is changing – for the better.
Biography:-
Toyota website. Hybrid Electric Vehicle Program. Toyota Prius. Details, FAQ. Toyota Prius. Details, Specs and Features. Toyota Prius, Technology. Statistics from www.fuelecomony.gov.
