Earth Day presentation on automotive technology
By Robin Arnette
When automotive expert Richard Cregar asked the audience at the Emerging Automotive Technology seminar who was interested in upgrading their transportation, just about everyone raised their hands. Whether they were interested in keeping their fuel costs low or helping the environment, they came to get the facts about the technologies available in today’s vehicles.
The NIEHS Environmental Awareness Advisory Committee (EAAC) hosted a presentation by Cregar May 3 as part of its Earth Day celebration.
Cregar is an instructor and department head for Advanced Transportation Technologies at Wilson Community College (http://www.wilsoncc.edu/) in Wilson, N.C. He said that the impetus for much of the interest in automotive technology came from the Obama administration's mandate that, by 2025, American automakers had to produce a fleet average of 54.5 miles per gallon. In other words, car companies must add up the U.S. Environmental Protection Agency's rated fuel economy for every car they sell and take the average, and the result must be 54.5 miles per gallon. Cregar rhetorically asked audience members, "Can they do that if they only produce gasoline-powered vehicles?"
Out of the several alternative fuel sources he mentioned (see text box), he said that electric drives were the most efficient.
Types of electric drives
According to Cregar, an example of a mild hybrid system is the eAssist from General Motors. It is currently in the Buick Regal and is the least efficient of the electric drives. A mild hybrid has an electric motor, but it can’t propel the vehicle on its own. It has to work with the internal combustion engine.
Honda has a medium hybrid system called Integrated Motor Assist (IMA). Medium hybrids differ from mild hybrids by the voltage used and the amount of torque assist available to help propel the vehicle. Medium hybrids also are incorporated into the powertrain, whereas the mild hybrid eAssist is basically a starter/generator that connects to the engine through the serpentine belt drive mechanism.
Cregar said full hybrids are where all the action is in the current market. The Toyota Prius pioneered the genre by producing a plug-in hybrid that has a large electric motor powerful enough to propel the vehicle on its own up to 35-40 mph. After that point, the gas engine switches on, seamlessly, to push the vehicle through increasing wind resistance. General Motors has provided some competition through its Chevy Volt, an extended-range electric vehicle (EREV). An EREV is driven nearly all the time, and at all speeds, by an even more powerful electric motor.
Practicing what he preaches
Even though he considers himself a diesel man, Cregar is the proud owner of a Chevy Volt. The Volt uses a lithium battery and is 92 percent efficient when it comes to its fuel consumption. Cregar received countless questions about his car, but one that was on many people’s minds was whether or not Cregar would be able to use his car if his family had to evacuate at a moment’s notice.
“With the exception of the Nissan Leaf, which is totally electric, all plug-ins, like the Volt, still use gas,” he said. “If you have gas in the gas tank, you can go to California right now just like you could in any other car.”
Dick Sloane, an EAAC coordinator, has known Cregar for several years and shares his passion for alternative transportation. Sloane knew Cregar was the right choice for this year’s Earth Day seminar. “We’ve gone to a lot of meetings together where he was the featured presenter,” Sloane said. “He always presented detailed engineering and scientific facts, not hype.”
Cregar stressed that oil will never go away, but it will be much more expensive in the future, because it will be harder to get and cost more to refine. He urges everyone to consider investing in transportation methods that don’t depend solely on gasoline. For more information, contact Cregar at firstname.lastname@example.org.
Gasoline isn't the only game in town
Cregar discussed the pros and cons of several other automotive fuel sources during his seminar.
- Flex Fuel is 85 percent ethanol and 15 percent gasoline. About 1,600 stations sell flex fuel for the 8 million flex vehicles that are currently on U.S. roads. Although flex owners save 10-12 percent in fuel costs, the vehicles still release carbon into the atmosphere.
- Biodiesel offers a clean fuel alternative, but Cregar says its low quantities and chemical instability hinders it from becoming a major player in vehicular drive systems. He said, "Petroleum has been around for a long time, so it's done doing what it has to do to itself. Since biofuels are new, they’re still changing, in the pump and in the tank."
- Clean Diesel vehicles are a viable option, because they get good mileage and can also use biodiesel fuel. A light-duty, clean diesel truck will have a fuel economy in the low 20s as opposed to the 12 miles per gallon of a regular gasoline pickup. Since clean diesel is still a fossil fuel, these vehicles emit greenhouse gases.
- Hydrogen vehicles are clean and only emit water out of their tailpipes. However, hydrogen is the lightest substance in the universe and, as such, poses challenges when it comes to capturing and storing it in large quantities. Cregar rejected hydrogen as a practicable energy source by saying, "Hydrogen is the fuel of the future and always will be."
- Compressed Natural Gas (CNG), or methane, is a clean energy source mostly used in trucking and heavy equipment. CNG comes from the process known as hydraulic fracturing, or fracking, and has a good long-term price forecast, because of increased domestic production. Nonetheless, CNG vehicles warm the environment, because methane contains carbon.