Ethanol is ethyl alcohol, also called grain alcohol. Chemically, fuel ethanol is identical—-albeit in a purer form--to the alcohol we drink. To make sure fuel ethanol isn’t used for frat house punch, it’s denatured, which means it is mixed with another chemical (usually gasoline) that renders it undrinkable.
Where Does Ethanol Come From?
Ethanol comes from one of these three raw material groups:
- starchy crops, such as corn
- sugary crop, like fruit or sugarcane
- cellulosic plants, such as trees or wild grasses
- While the process for making ethanol varies somewhat depending on the feedstock, the basic steps are the same.
- The feedstock is milled or crushed, and may be treated with chemicals or enzymes. This step is designed to yield as much fermentable sugar as possible from the feedstock.
- Yeast is added to the prepared feedstock and sugars are converted to alcohol.
- The alcohol is extracted from the mixture by boiling it in a distiller.
Nearly all the ethanol made in the United States uses corn for a feedstock. Brazil, the world’s largest ethanol producer, makes ethanol from sugarcane. Other countries, such as France, use sugar beets and wheat as their primary feedstocks. With current technology, it is easiest and most efficient to produce ethanol from sugar crops, since the sugars in these feedstocks are readily available for fermentation. In the future, advances in ethanol production may increase yields and decrease the cost of producing ethanol from cellulosic material.
The Blends
Most likely, you're using ethanol in your car without even knowing it. In many regions, small amounts of ethanol are blended with gasoline to reduce emissions. Mixtures as high as E10 (10 percent ethanol and 90 percent gasoline) are safe for use in most vehicles, including hybrid models such as the Toyota Prius and Honda Civic Hybrid.
Much of the news lately has been about fuel blends that have higher ethanol content. The most common is E85 (85 percent ethanol and 15 percent gasoline), which only can be used in vehicles that are designed for that fuel. Currently, no hybrid models accept E85 fuel, but more than 20 E85-compatible cars and trucks (called “flexible-fuel vehicles”) are available now from four major manufacturers.
from Hybridcars.com
Monday, July 02, 2007
Saturday, June 02, 2007
How Electric Vehicles Work
By Brad Berman
The Power of the Gas Pump, By the Numbers
It doesn't take much to spark a conversation with an electric car advocate. A casual comment about the drawbacks of an EV - doesn't it take a long time to recharge? - will quickly spin into passionate arguments about efficiency, kilowatt-hours and states of charge. Electric car detractors are no less vociferous about the superiority of petro-power. Why do folks from both sides of the argument usually fail to win new converts? Because laypeople are clueless about even the most basic technical terms that underpin the discussion. So here comes my attempt to translate EV geek speak into English.
Power to the People
The first important issue to address is the fundamental difference between energy and power. There's a difference? There is - and if you can't readily tell the difference between the two, don't feel bad. Experts, officials and the media frequently confuse these terms. The difference between energy and power is quite simple:
- Energy is the ability to do work
- Power is the rate at which work is done
Understanding the difference is very important to the overall understanding of electricity and electrical systems, including electric cars and hybrid vehicles. The amount of energy in your batteries (or in your gas tank, for that matter) indicates the distance you can travel before refueling. That's known as range, and it's perhaps the most important issue involved in getting more electric cars on the road. The power rating of your electric motor (or gas engine) tells you how quickly you can turn that energy into useful work, such as vehicle acceleration.
To make this more useful in comparing gas-engine cars and electric vehicles, we need to introduce two more terms:
- kilowatt (a measure of power, abbreviated kW)
- kilowatt-hour (a measure of energy, abbreviated kW-hr or kWh)
Let's begin by flipping on a 100-watt light bulb - better yet, make that 10 of those 100-watt light bulbs. With all 10 bulbs illuminated, you are burning 1 kilowatt of power. Leave those light on for an hour, and you will have used 1 kilowatt-hour of energy. Get it?
In general terms, that same amount of energy - 1 kilowatt-hour - will move an electric car about four miles down the road. The amount of electric fuel that an EV driver can store in batteries depends on a lot of factors: the number and size/shape of batteries, and how willing you are to fully charge and discharge those batteries (thus affecting how long the batteries last). Those are all energy issues. The power issues, on the other hand, are more circumscribed: recharging your batteries from a common household outlet occurs at 1.5 kilowatts. Without getting into complicated math, just know that 1.5 kilowatts is a relatively small power spigot and it's going to take the driver of an EV a good few of hours, if not seven or eight, to recharge batteries capable of a couple hundred miles of driving. (To be more specific: At 4 miles range per kWh, one can charge from an ordinary wall outlet at a rate of, at most, 6 miles of added range per hour of charging, or "6 mph." Then there is the taper-off toward the end of charge, making the last 10-20% of charge even longer.)
On the other hand, an internal combustion engine stores its energy in the form of gasoline - and gas packs a 33 kilowatt-hour punch in every gallon. There's a lot of juice in that juice. Unfortunately, the tank-to-wheels efficiency of the gas engine is five or six times less than that of an electric motor's battery-to-wheels efficiency. If you consider what it took to extract the petroleum from the well, transport it to a refinery in supertankers and big rigs (both of which are also burning fossil fuels), and then inefficiently burn it in internal combustion engines, then the wastefulness looks even more extreme. (And that's without calculating the geopolitical and environmental effects of that oil supply chain.)
But for the moment, I'm not concerned about efficiency or sea otters. I need to get to work, my car is running nearly empty, and I need to quickly fill up on those "33 kilowatt-hour" gallons - or my boss will not be happy. Let's assume that my car's gasoline tank is 10 gallons. In the five minutes it took to fill up, I would have placed 330 kilowatt-hours of energy in my tank.
If I tried to get the same amount of energy from a household outlet, it would take me about nine days. Of course, it doesn't take nine days to recharge an EV, because the efficiency of an EV allows the driver to put less energy in the "tank" and still receive an adequate charge. But the comparison shows how gasoline became such a popular fuel over the past century: it allows us to put a lot of energy in our cars very quickly.
For the sake of comparing refueling times of gas and electric cars, we need to look at power - again the rate of transferring energy or, in this case, refueling. So, in power terms, I refuel my gas-powered car at 10 gallons per five minutes or 120 gallons per hour. Those 120 gallons - at 33 kilowatt-hours in a gallon - put 3,960 kilowatt-hours in my tank.
If I haven't lost you entirely, we can at last calculate the power of the gas pump:
- 3,960 kilowatt-hours per hour, or 3,960 kilowatts
If I did lose you, that's OK. We have the numbers necessary to compare the power of the gas pump versus the power of the electric cord.
- The power of the gas pump is 3,960 kilowatts
- The power of the electric cord is 1.5 kilowatts
- The gas pump is 2,640 times more powerful than the electric cord
Yes, I've disregarded the greater efficiency of the EV versus the gas engine when the fuel is used. But you get the point.
The next equation to consider is cost, but it doesn't involve another math lesson. The more important equation is not fundamentally mathematical: are we willing forgo the five-minute fillup in exchange for the overnight recharge if it helps us break the 100-year-old dominance of the internal combustion engine, and avert future oil price shocks, oil wars, and global warming? That's your homework assignment.
more in hybridcars.com
The Power of the Gas Pump, By the Numbers
It doesn't take much to spark a conversation with an electric car advocate. A casual comment about the drawbacks of an EV - doesn't it take a long time to recharge? - will quickly spin into passionate arguments about efficiency, kilowatt-hours and states of charge. Electric car detractors are no less vociferous about the superiority of petro-power. Why do folks from both sides of the argument usually fail to win new converts? Because laypeople are clueless about even the most basic technical terms that underpin the discussion. So here comes my attempt to translate EV geek speak into English.
Power to the People
The first important issue to address is the fundamental difference between energy and power. There's a difference? There is - and if you can't readily tell the difference between the two, don't feel bad. Experts, officials and the media frequently confuse these terms. The difference between energy and power is quite simple:
- Energy is the ability to do work
- Power is the rate at which work is done
Understanding the difference is very important to the overall understanding of electricity and electrical systems, including electric cars and hybrid vehicles. The amount of energy in your batteries (or in your gas tank, for that matter) indicates the distance you can travel before refueling. That's known as range, and it's perhaps the most important issue involved in getting more electric cars on the road. The power rating of your electric motor (or gas engine) tells you how quickly you can turn that energy into useful work, such as vehicle acceleration.
To make this more useful in comparing gas-engine cars and electric vehicles, we need to introduce two more terms:
- kilowatt (a measure of power, abbreviated kW)
- kilowatt-hour (a measure of energy, abbreviated kW-hr or kWh)
Let's begin by flipping on a 100-watt light bulb - better yet, make that 10 of those 100-watt light bulbs. With all 10 bulbs illuminated, you are burning 1 kilowatt of power. Leave those light on for an hour, and you will have used 1 kilowatt-hour of energy. Get it?
In general terms, that same amount of energy - 1 kilowatt-hour - will move an electric car about four miles down the road. The amount of electric fuel that an EV driver can store in batteries depends on a lot of factors: the number and size/shape of batteries, and how willing you are to fully charge and discharge those batteries (thus affecting how long the batteries last). Those are all energy issues. The power issues, on the other hand, are more circumscribed: recharging your batteries from a common household outlet occurs at 1.5 kilowatts. Without getting into complicated math, just know that 1.5 kilowatts is a relatively small power spigot and it's going to take the driver of an EV a good few of hours, if not seven or eight, to recharge batteries capable of a couple hundred miles of driving. (To be more specific: At 4 miles range per kWh, one can charge from an ordinary wall outlet at a rate of, at most, 6 miles of added range per hour of charging, or "6 mph." Then there is the taper-off toward the end of charge, making the last 10-20% of charge even longer.)
On the other hand, an internal combustion engine stores its energy in the form of gasoline - and gas packs a 33 kilowatt-hour punch in every gallon. There's a lot of juice in that juice. Unfortunately, the tank-to-wheels efficiency of the gas engine is five or six times less than that of an electric motor's battery-to-wheels efficiency. If you consider what it took to extract the petroleum from the well, transport it to a refinery in supertankers and big rigs (both of which are also burning fossil fuels), and then inefficiently burn it in internal combustion engines, then the wastefulness looks even more extreme. (And that's without calculating the geopolitical and environmental effects of that oil supply chain.)
But for the moment, I'm not concerned about efficiency or sea otters. I need to get to work, my car is running nearly empty, and I need to quickly fill up on those "33 kilowatt-hour" gallons - or my boss will not be happy. Let's assume that my car's gasoline tank is 10 gallons. In the five minutes it took to fill up, I would have placed 330 kilowatt-hours of energy in my tank.
If I tried to get the same amount of energy from a household outlet, it would take me about nine days. Of course, it doesn't take nine days to recharge an EV, because the efficiency of an EV allows the driver to put less energy in the "tank" and still receive an adequate charge. But the comparison shows how gasoline became such a popular fuel over the past century: it allows us to put a lot of energy in our cars very quickly.
For the sake of comparing refueling times of gas and electric cars, we need to look at power - again the rate of transferring energy or, in this case, refueling. So, in power terms, I refuel my gas-powered car at 10 gallons per five minutes or 120 gallons per hour. Those 120 gallons - at 33 kilowatt-hours in a gallon - put 3,960 kilowatt-hours in my tank.
If I haven't lost you entirely, we can at last calculate the power of the gas pump:
- 3,960 kilowatt-hours per hour, or 3,960 kilowatts
If I did lose you, that's OK. We have the numbers necessary to compare the power of the gas pump versus the power of the electric cord.
- The power of the gas pump is 3,960 kilowatts
- The power of the electric cord is 1.5 kilowatts
- The gas pump is 2,640 times more powerful than the electric cord
Yes, I've disregarded the greater efficiency of the EV versus the gas engine when the fuel is used. But you get the point.
The next equation to consider is cost, but it doesn't involve another math lesson. The more important equation is not fundamentally mathematical: are we willing forgo the five-minute fillup in exchange for the overnight recharge if it helps us break the 100-year-old dominance of the internal combustion engine, and avert future oil price shocks, oil wars, and global warming? That's your homework assignment.
more in hybridcars.com
Friday, May 04, 2007
EPA invents battery-less hybrid system
Hybrid drivetrain uses compressed fluid instead of electricity. To be tested on UPS trucks.
By Peter Valdes-Dapena, CNNMoney.com staff writer.
NEW YORK (CNN/Money) - The Environmental Protection Agency says it can help drivers save fuel. It has said that for a long time, of course, but this time it's not talking about providing fuel mileage data for car shoppers. It's talking about a new invention created in its own Ann Arbor, Mich. research laboratories.
Called hydraulic hybrid technology, the system uses energy stored up during braking to help propel a vehicle during acceleration. The energy is stored in pressurized hydraulic fluid, the same sort of fluid used in brake lines and for power steering.
Ordinarily, when a driver applies the brakes in a car the energy removed from the vehicle's forward motion is simply lost as heat through the car's brake pads and rotors.
In gasoline-electric hybrids, like the Toyota Prius, some of that energy is recaptured through generators that charge batteries that, in turn, can help provide supplementary power to the vehicle.
In the EPA's hydraulic hybrid system, braking pressure is used to power pumps that compress hydraulic fluid. This stores energy in the same way you would if you squeezed a spring with your hands. When needed, the pressure is released and the expanding hydraulic fluid is used to power gears that help turn the vehicle's wheels.
Also, just as a gasoline-electric hybrid's gas engine can charge the batteries directly during highway cruising, the hydraulic hybrid's engine can also pump up the pressurized fluid tanks as the vehicle drives.
The EPA holds about 20 patents for technology used in the new system, said Margo Oge, director of the EPA's office of transportation and air quality.
While the EPA labs in Ann Arbor, Mich., are better known for creating new fuel mileage and emissions tests and standards, in recent years the labs have also begun working on creating new technologies for cleaner and more fuel-efficient vehicles.
The EPA began working on the system about 10 years ago, said Oge, under a Clinton administration program to research clean energy technology.
Pros and cons
There is a major advantage to the EPA's new system and one major disadvantage, the agency said. The advantage is its simplicity and relatively low cost. The system would cost an estimated $600 to install on a mass-production basis, the agency estimates, compared to $3,000 to $6,000 for an electric hybrid system.
The disadvantage is the system's weight, the EPA says. According to a 2004 EPA report, a hydraulic hybrid SUV would weigh about 190 pounds more than a conventional SUV. That means the EPA's system is most applicable to trucks where the added weight would make a smaller overall difference, the agency said.
The added weight of the system is similar to the weight of an electric hybrid system, although the EPA itself cites weight as a disadvantage.
Like gasoline-electric hybrids, hydraulic hybrid vehicles would see greater fuel savings in stop-and-go city driving than in steady highway cruising.
While the system could pay for itself in as little as a year in a heavier vehicle like big four-wheel-drive SUV, it would take at least four years to pay for itself in a midsized car, according to the EPA's report.
Still, the EPA says, that's a shorter payback time than drivers of gasoline-electric hybrids will see.
The EPA's system was demonstrated at an engineering conference last year on a prototype Ford Expedition SUV and will be used next year in at least one UPS delivery truck next year.
The UPS truck could get as much a 70 percent increase in fuel efficiency in city routes, the EPA estimates, and the added cost of the trucks should be paid off in fuel savings in about 2.5 years.
All these vehicles are diesel powered. Diesel engines are inherently more fuel efficient, to begin with, than gasoline engines. The use of diesel also allows the EPA to show off "clean diesel" technology it has also developed in its laboratories.
The system is currently being developed in partnership with International Truck and Engine Corp., Eaton Hydraulics, Parker Hannifin Corp., which specializes in making hydraulic controls, and the U.S. Army.
By Peter Valdes-Dapena, CNNMoney.com staff writer.
NEW YORK (CNN/Money) - The Environmental Protection Agency says it can help drivers save fuel. It has said that for a long time, of course, but this time it's not talking about providing fuel mileage data for car shoppers. It's talking about a new invention created in its own Ann Arbor, Mich. research laboratories.
Called hydraulic hybrid technology, the system uses energy stored up during braking to help propel a vehicle during acceleration. The energy is stored in pressurized hydraulic fluid, the same sort of fluid used in brake lines and for power steering.
Ordinarily, when a driver applies the brakes in a car the energy removed from the vehicle's forward motion is simply lost as heat through the car's brake pads and rotors.
In gasoline-electric hybrids, like the Toyota Prius, some of that energy is recaptured through generators that charge batteries that, in turn, can help provide supplementary power to the vehicle.
In the EPA's hydraulic hybrid system, braking pressure is used to power pumps that compress hydraulic fluid. This stores energy in the same way you would if you squeezed a spring with your hands. When needed, the pressure is released and the expanding hydraulic fluid is used to power gears that help turn the vehicle's wheels.
Also, just as a gasoline-electric hybrid's gas engine can charge the batteries directly during highway cruising, the hydraulic hybrid's engine can also pump up the pressurized fluid tanks as the vehicle drives.
The EPA holds about 20 patents for technology used in the new system, said Margo Oge, director of the EPA's office of transportation and air quality.
While the EPA labs in Ann Arbor, Mich., are better known for creating new fuel mileage and emissions tests and standards, in recent years the labs have also begun working on creating new technologies for cleaner and more fuel-efficient vehicles.
The EPA began working on the system about 10 years ago, said Oge, under a Clinton administration program to research clean energy technology.
Pros and cons
There is a major advantage to the EPA's new system and one major disadvantage, the agency said. The advantage is its simplicity and relatively low cost. The system would cost an estimated $600 to install on a mass-production basis, the agency estimates, compared to $3,000 to $6,000 for an electric hybrid system.
The disadvantage is the system's weight, the EPA says. According to a 2004 EPA report, a hydraulic hybrid SUV would weigh about 190 pounds more than a conventional SUV. That means the EPA's system is most applicable to trucks where the added weight would make a smaller overall difference, the agency said.
The added weight of the system is similar to the weight of an electric hybrid system, although the EPA itself cites weight as a disadvantage.
Like gasoline-electric hybrids, hydraulic hybrid vehicles would see greater fuel savings in stop-and-go city driving than in steady highway cruising.
While the system could pay for itself in as little as a year in a heavier vehicle like big four-wheel-drive SUV, it would take at least four years to pay for itself in a midsized car, according to the EPA's report.
Still, the EPA says, that's a shorter payback time than drivers of gasoline-electric hybrids will see.
The EPA's system was demonstrated at an engineering conference last year on a prototype Ford Expedition SUV and will be used next year in at least one UPS delivery truck next year.
The UPS truck could get as much a 70 percent increase in fuel efficiency in city routes, the EPA estimates, and the added cost of the trucks should be paid off in fuel savings in about 2.5 years.
All these vehicles are diesel powered. Diesel engines are inherently more fuel efficient, to begin with, than gasoline engines. The use of diesel also allows the EPA to show off "clean diesel" technology it has also developed in its laboratories.
The system is currently being developed in partnership with International Truck and Engine Corp., Eaton Hydraulics, Parker Hannifin Corp., which specializes in making hydraulic controls, and the U.S. Army.
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