hybrid car homework
Posted: Thu Nov 02, 2006 7:34 am
i had to write a paper based on an interview for my environmental ethics class. Figured i'd stick it up on the web, to be immortalized and copywrited.
i wrote this pretty drunk.Having wrenched on cars as a hobby and car owner for the last 7 years, hybrid vehicles have always piqued my curiosity. This curiosity took me to Stevens Creek Toyota, where I talked to **** ***. Rather than be entirely honest and admit that I was a student gathering information for a report and risk being snubbed, I dressed and played the part of the wealthy hippie, and was thus able to get a very good interview.
I drove a hybrid Camry and a Prius, both of which are very nice cars. The Prius was very slow, but the screen that displayed where the power was going and the amazingly quiet interior meant that I wasn’t bored as a driver. The Camry, however, was a rather quick car, which didn’t make much sense for a green vehicle. Apparently while the Prius is a world market vehicle, the Camry hybrid was designed with the American palette in mind, and so it’s faster and more economical than a normal four cylinder model. For all this better car, I was offered an out-the-door price that was about 7 thousand dollars more than the equivalent 4 cylinder; a difference that will never pay for itself in gas savings.
Toyota produces the most advanced hybrids in the world. Any other manufacturer’s hybrid car is a normal internal combustion engine with an electric motor instead of a flywheel. The engine runs all the time, and the electric motor can kick in extra power when necessary, recharging by using the electric motor as a generator. These cars save power by allowing the car to have a smaller engine while still maintaining the same peak output. Toyota’s hybrids go further though. They can be run entirely off the electric motor at low speed and in reverse. The gearbox is simpler because it doesn’t need to have a reverse gear; the electric motor does it all. When you stop, the engine turns off, and when you press the gas to go again, the electric motor uses its tremendous torque to get the car rolling again, only engaging the gas engine when more power is required.
I mentioned that I had heard that the hybrid cars did better on emissions tests than they did in the real world, and was told that that was because the owners didn’t necessarily drive their cars in a manner that optimized the hybrid system. The hybrid cars loved cruise control; any chance to let the computer decide when to kick on the gas engine (it would cruise at low speed on electric power, but goosing the throttle a little would turn on the gas) reaped huge dividends. It didn’t seem intuitive, but the hybrid system benefited when the driver got on the brakes as early as possible; the system could only recharge the batteries under light braking, heavy normal stops (like my normal stop, I’m told) does little to recharge. The hybrid really suffers when you only make short trips; if the gas engine never warms up then it can’t go to full efficiency.
I was concerned that the hybrid vehicles’ batteries would have considerable environmental cost. In addition to the initial cost of producing the batteries, the batteries probably have toxic substances, most notably lead. Toyota doesn’t use lead-acid batteries; they’ve switched to nickel metal hydride. They’ve even posted a phone number on the bottom of the batteries; they pay to see them returned to the company so they can be recycled.
The batteries are an extra 200lbs, and it seemed like the extra weight of the system would compromise the character and safety of the vehicle. This was the case in the Camry, where the battery packs were stuck behind the back seats, eating into the trunk, but not so much in the Prius, which was designed around a hybrid drive train. The Prius has the batteries in the floor and in the chassis rails, where they have minimal effect on the roll of the vehicle and don’t eat into the passenger compartment.
I was frequently reminded that both the Camry and Prius were AT-PZEV, or Advanced Technology Partial Zero Emissions Vehicles, the cleanest on the market, producing 90% less emission than a typical new car. This seemed somewhat remarkable at the time, but further research at home revealed that this meant both cars were PZEV hybrids, and while there aren’t many AT-PZEV cars, there are 32 PZEV cars on the market, or non-hybrids conforming to the same emissions standards.
There’s currently a 2000$ tax credit available when you buy a hybrid vehicle. With the credit in place, the hybrid car’s additional price will be reabsorbed by the savings on fuel before the car is terribly old. It takes more initial capital to get a hybrid car, though, and so many people may feel that additional perks are necessary to make a hybrid car worthwhile.
