Wednesday, January 23, 2008

What is the Best Way to Power Our Cars? Part 3

For the last blog on the topic of alternative fuels in cars, I am going to focus on Electric Powered Vehicles (EVs)

What are they? They are vehicles that are powered by an electric motor. The electric motor is connected to a controller. And that controller is connected to a battery source in the car.

How does it work? Electric cars can use AC or DC electric motors. Without getting into too much electricity jargon, AC stands for alternating current and DC stands for direct current. AC motors are similar to a gasoline engine in that it requires a transition to operate. A DC motor, however, is designed so that you can have continuous acceleration. Both types of engines have their benefits and actually in the case of AC powered cars, a DC components is needed its operation.

These motors can be finely controlled and provide high torque from rest, unlike ICEV, and do not need gears to match power curves. This removes the need for gearboxes and torque converters. Internal combustion engines can weight almost 1000 pounds; where as, an EV motor can weight 75-100 lbs. EVs require a lot of batteries to power their motors, but they can be placed strategically around the base of the car for added stability (rather then a front heavy car).

Speaking of batteries, that needs to be discussed. The batteries are what makes or breaks an Electric Vehicle. And right now it is what is holding back the industry. There are a few important things that these batteries need to accomplish:

First, to give these cars a long range (50-300 miles) these batteries need to be able to hold a lot of charge. Next, to charge quickly (3-6 hours at night). Also, they need to last a long time (5-10 years).

These types of needs are specific to our perception of how any car should preform. We are used driving 200 miles before having to stop for 10 minutes to fill up on gas. And no one wants to have to shell out 2 grand on new parts every 2 years.

What are the benefits? These cars are a lot simpler than ICEV. There are a less parts in an EV, so that means a lot less money for repairs and replacements. When GM EV1s were brought in for repairs there was very little work that needed to be done. Air in the tires, maybe an aliment check, then you were on your way.

In addition, they release almost no air pollutants at the place they are operated. This would be a HUGE improvement to mobile pollution source reduction, one of the most difficult types of pollution to control.

As we talked about in the last section, hybrids use electric energy to get up to crusing speed so that the gas engine can work most efficiency. Electric motors often achieve 90% energy conversion efficiency over the FULL range of speeds and power output. Combine this with regenerative braking and you are really using your energy to the fullest.

Another advantage is that electric vehicles typically have less vibration and noise pollution than a ICEV, whether it is at rest or in motion.

Are EVs the answer? The answer in my opinion is 100% yes. Unfortunately, right now there are not that many available.

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