TNT
08-07-2007, 03:47 AM
Grading the fuel-saving technologies of the future
By Dan Carney, Contributor Email
Hybrid-electrics, fuel cells, forced-induction gerbil-powered wheels: Are these the power plants of the automobile's near-term future?
The federal government is pondering an increase in the CAFE requirement, the complicated formula for the average fuel economy required from each manufacturer's lineup of cars or trucks. Within a decade, you might not recognize the car in your driveway.
We thought it would be a good time to review some of the fuel-saving technologies at hand. Our list of technologies includes hybrids of various new types and flavors, even the plug-in hybrid, the holy grail for alternative-fuel enthusiasts. And there are supplements to the grimy old internal-combustion engine such as diesel fuel, direct injection for gasoline, and turbocharging.
Hybrids: Combining part-time power from a battery-operated electric motor with a conventional internal combustion engine, the hybrid boosts fuel economy by roughly one-third in real-world driving. Unfortunately it also carries a substantial price premium of several thousand dollars.
Toyota has sold more than 640,000 hybrid vehicles worldwide since the Prius was first introduced in Japan in 1997, and more than 260,000 Prius sedans have found their way to America since the car was first introduced here in 2000.
Grade: B+
Hybrids are effective at improving fuel efficiency, but the technology is costly, and its benefits are largely restricted to low-speed metropolitan driving.
Belt-Drive Hybrids: This is basically an automatic stop/start feature for a conventional engine that relies on a souped-up alternator to get the power plant into action again. This alternator technology can be bolted onto existing engines and boosts fuel efficiency by about 10 percent.
The GM system not only boosts engine power with its 110 pound-feet of torque but also functions as a 3-kilowatt generator. If the power goes out at your house, you can plug that fridge in the garage and keep the beer cold.
Grade: B
Mild hybrid systems are cheaper, but bring modest benefits. Also the automatic stop/start feature is compromised when the air-conditioning is engaged. The Saturn Aura Green Line will feature this technology when it arrives this spring.
Two-Mode Hybrids: In two-mode hybrids, the electric motor takes advantage of the transmission's gear multiplication (unlike today's hybrid drivetrains), so a smaller, more easily packaged and more affordable electric motor and battery pack can deliver useful electric-only acceleration. Skeptical about the value of hybrid pickup trucks? A vehicle that improves its fuel economy from 14 mpg to 16 mpg saves the same amount of gas annually as a vehicle that improves its economy from 35 mpg to 51 mpg.
Grade: B+
Two-mode hybrids have the potential to be both cheaper and more efficient than regular hybrids and the technology works as well with a powerful sports car as it does with a heavy pickup truck. GM has announced plans to introduce two-mode hybrid pickups.
Plug-In Hybrids: The plug-in hybrid uses power produced from sources other than imported oil (coal, natural gas, nuclear power or wind-generated power) and adapts it for transportation in the form of electricity. A plug-in hybrid has a bigger battery pack to permit more frequent use of electric power, plus a plug that allows the vehicle to be recharged by household electric current.
Cars are only on the road about 5 percent of the time, so the electric power grid can keep a fleet of hybrids recharged during times when utilities have a minimal amount of power demand, says Tony Markel, a senior engineer at the National Renewable Energy Lab.
Grade: B-
This is the holy grail of the alternative-fuel enthusiasts, and the topic on the lips of every news commentator in America. Indeed, the technology has fantastic potential to reduce oil consumption. But there are questions of capacity from the power grid, plus there are environmental consequences for the fuel required to charge the electric grid. And the realities of the charging cycle for batteries mean that the notion of driving to and from work without ever starting the gas engine is impractical.
Fuel Cells: Fuel cells produce power silently and cleanly, turning hydrogen and atmospheric oxygen into pure H2O. Manufacturers have made huge strides overcoming the numerous challenges to produce practical vehicles powered by fuel cells. These include startup time, size, cost and even sensitivity to cold. (It's not nice when the water inside freezes.)
Honda has handed the keys to one of its 20 FCX fuel-cell prototypes to 17-year-old actress Q'orianka Kilcher. But not to you.
Grade: D-
Despite development advances, fuel cells remain prohibitively expensive. "This is a technology whose day has not come, and won't come for a couple decades," says James Kliesch, research associate at the American Coalition for an Energy-Efficient Economy.
Diesels: Diesels aren't the greasy, smelly, slow engines they used to be. Hey, you aren't the greasy, smelly teenager you used to be, are you? Well, the diesel engine has grown up, too, so now it's mostly quiet, clean (EPA Tier II Bin 5 starting in 2009), and even fast. (Look at the taillights of the Audi R10 racecar, because that's all any of its gas-powered competitors have ever seen.)
If just one-third of the U.S. passenger fleet were diesel-powered, we'd save 1.4 million barrels of oil per day, says the Diesel Technology Forum.
Grade: B+
The diesel gets great mileage, readily accepts domestic biodiesel as fuel, and it's in production today. But the emissions-control systems required to meet 2009 standards are costly (think $2 grand) and complex.
Diesel Hybrid Electrics: Now we're talking. Diesel engines and hybrid electric drivetrains go together like chocolate and peanut butter, as demonstrated by their use in locomotives for the last half-century. The combination of torquey, efficient motors meets the desire of enthusiasts for sporty power, and it doesn't punish us with high fuel bills or social ostracism.
Chrysler, Ford and GM produced concept cars under the Clinton administration's Partnership for the Next Generation of Vehicles, and each used a diesel-electric hybrid powertrain to achieve the goal of building a five-passenger sedan that could reach 80 mpg.
Grade: C
Ready for prime time, but get ready to open your wallet, because a diesel hybrid could cost $10 grand more than an identical gas-powered car. Look for Mercedes to introduce the first diesel-electric hybrid in an S-Class sedan.
Turbochargers: Yeah, a turbocharger can make your slammed Civic rip off a 9.0-second quarter-mile. But it can also help boost the performance of a small engine when you need it, while allowing the powertrain to deliver better gas mileage the rest of the time.
The turbocharged Saturn Sky Red Line and Pontiac Solstice GXP actually deliver better gas mileage than the normally aspirated models, thanks to the use of a smaller-displacement engine and a taller final-drive ratio.
Grade: B-
The turbocharger is getting better all the time, but it still represents another layer of complexity and expense under the hood.
Direct Gasoline Injection: Here's the idea: Blast the gas directly into the combustion chamber instead of the intake ports, which helps the engine breathe better and extract more power from the fuel.
Direct gasoline injection bolsters the low- and midrange torque of the Mazda Direct Injection Spark Ignition (DISI) engine by 10 percent.
Grade: B-
Direct injection has helped improve fuel economy, and forthcoming generations of the technology will help even more, promises Udo Lindner, manager of powertrain development for BMW's 3 Series cars. But so far the benefit has fallen short of expectations. "We have found that with direct injection the power goes up much more rapidly than the efficiency," notes GM Vice Chairman Bob Lutz. "We would prefer that it were the other way around."
Cylinder Deactivation: If eight cylinders burn more gasoline than four, how about if you shut four of them off when you don't need that small-block V8 power? Chrysler, GM and Honda all are using the concept to idle unneeded cylinders under light loads.
The muscle-bound Chevy Impala SS V8 equipped with GM's Displacement-on-Demand cylinder-deactivation technology delivers an EPA-rated 27 mpg on the highway, just 1 mpg less than the rating of the similarly sized and powerful Lexus GS 450h V6 hybrid.
Grade: C+
In a vehicle equipped with this technology, it's virtually impossible to notice the change when half the cylinders go off line. At the same time, it's equally hard to notice an improvement at the gas pump. In both cases, a difference is there, but you'll only notice if you are looking for it.
Lightweight Materials: Lighter cars use less gas and go faster, so everyone is happy. But today's vehicles have to meet strict crash-safety requirements, and the expensive materials needed to lighten them are viable only in expensive cars.
New materials demand investment in research, as Mercedes-Benz discovered during a crash test of an early prototype S-Class when the high-strength steel shattered like glass. Mercedes had to spend some time to research the heat treatment and welding techniques, explains Hans Multhaupt, vice president of program management at Mercedes.
Grade: C
Advanced lightweight materials like the carbon-fiber roof for the BMW M6 and new M3 are cool, but the cost will limit their use.
Advanced Transmissions: Continuously variable transmissions and advanced six-, seven- and eight-speed automatics reduce the penalty for automatic gear selection.
A six-speed automatic transmission is about 5 percent more efficient than an old four-speed slushbox.
Grade: B-
Advanced transmissions help trim fuel consumption, but we've always been able to maximize mileage just by shifting for ourselves.
Gerbil Wheel: Still no word on the forced-induction gerbil-powered wheel, however, so we're going to have to fail this exciting bio-friendly technology until we have a chance to study it further.
By Dan Carney, Contributor Email
Hybrid-electrics, fuel cells, forced-induction gerbil-powered wheels: Are these the power plants of the automobile's near-term future?
The federal government is pondering an increase in the CAFE requirement, the complicated formula for the average fuel economy required from each manufacturer's lineup of cars or trucks. Within a decade, you might not recognize the car in your driveway.
We thought it would be a good time to review some of the fuel-saving technologies at hand. Our list of technologies includes hybrids of various new types and flavors, even the plug-in hybrid, the holy grail for alternative-fuel enthusiasts. And there are supplements to the grimy old internal-combustion engine such as diesel fuel, direct injection for gasoline, and turbocharging.
Hybrids: Combining part-time power from a battery-operated electric motor with a conventional internal combustion engine, the hybrid boosts fuel economy by roughly one-third in real-world driving. Unfortunately it also carries a substantial price premium of several thousand dollars.
Toyota has sold more than 640,000 hybrid vehicles worldwide since the Prius was first introduced in Japan in 1997, and more than 260,000 Prius sedans have found their way to America since the car was first introduced here in 2000.
Grade: B+
Hybrids are effective at improving fuel efficiency, but the technology is costly, and its benefits are largely restricted to low-speed metropolitan driving.
Belt-Drive Hybrids: This is basically an automatic stop/start feature for a conventional engine that relies on a souped-up alternator to get the power plant into action again. This alternator technology can be bolted onto existing engines and boosts fuel efficiency by about 10 percent.
The GM system not only boosts engine power with its 110 pound-feet of torque but also functions as a 3-kilowatt generator. If the power goes out at your house, you can plug that fridge in the garage and keep the beer cold.
Grade: B
Mild hybrid systems are cheaper, but bring modest benefits. Also the automatic stop/start feature is compromised when the air-conditioning is engaged. The Saturn Aura Green Line will feature this technology when it arrives this spring.
Two-Mode Hybrids: In two-mode hybrids, the electric motor takes advantage of the transmission's gear multiplication (unlike today's hybrid drivetrains), so a smaller, more easily packaged and more affordable electric motor and battery pack can deliver useful electric-only acceleration. Skeptical about the value of hybrid pickup trucks? A vehicle that improves its fuel economy from 14 mpg to 16 mpg saves the same amount of gas annually as a vehicle that improves its economy from 35 mpg to 51 mpg.
Grade: B+
Two-mode hybrids have the potential to be both cheaper and more efficient than regular hybrids and the technology works as well with a powerful sports car as it does with a heavy pickup truck. GM has announced plans to introduce two-mode hybrid pickups.
Plug-In Hybrids: The plug-in hybrid uses power produced from sources other than imported oil (coal, natural gas, nuclear power or wind-generated power) and adapts it for transportation in the form of electricity. A plug-in hybrid has a bigger battery pack to permit more frequent use of electric power, plus a plug that allows the vehicle to be recharged by household electric current.
Cars are only on the road about 5 percent of the time, so the electric power grid can keep a fleet of hybrids recharged during times when utilities have a minimal amount of power demand, says Tony Markel, a senior engineer at the National Renewable Energy Lab.
Grade: B-
This is the holy grail of the alternative-fuel enthusiasts, and the topic on the lips of every news commentator in America. Indeed, the technology has fantastic potential to reduce oil consumption. But there are questions of capacity from the power grid, plus there are environmental consequences for the fuel required to charge the electric grid. And the realities of the charging cycle for batteries mean that the notion of driving to and from work without ever starting the gas engine is impractical.
Fuel Cells: Fuel cells produce power silently and cleanly, turning hydrogen and atmospheric oxygen into pure H2O. Manufacturers have made huge strides overcoming the numerous challenges to produce practical vehicles powered by fuel cells. These include startup time, size, cost and even sensitivity to cold. (It's not nice when the water inside freezes.)
Honda has handed the keys to one of its 20 FCX fuel-cell prototypes to 17-year-old actress Q'orianka Kilcher. But not to you.
Grade: D-
Despite development advances, fuel cells remain prohibitively expensive. "This is a technology whose day has not come, and won't come for a couple decades," says James Kliesch, research associate at the American Coalition for an Energy-Efficient Economy.
Diesels: Diesels aren't the greasy, smelly, slow engines they used to be. Hey, you aren't the greasy, smelly teenager you used to be, are you? Well, the diesel engine has grown up, too, so now it's mostly quiet, clean (EPA Tier II Bin 5 starting in 2009), and even fast. (Look at the taillights of the Audi R10 racecar, because that's all any of its gas-powered competitors have ever seen.)
If just one-third of the U.S. passenger fleet were diesel-powered, we'd save 1.4 million barrels of oil per day, says the Diesel Technology Forum.
Grade: B+
The diesel gets great mileage, readily accepts domestic biodiesel as fuel, and it's in production today. But the emissions-control systems required to meet 2009 standards are costly (think $2 grand) and complex.
Diesel Hybrid Electrics: Now we're talking. Diesel engines and hybrid electric drivetrains go together like chocolate and peanut butter, as demonstrated by their use in locomotives for the last half-century. The combination of torquey, efficient motors meets the desire of enthusiasts for sporty power, and it doesn't punish us with high fuel bills or social ostracism.
Chrysler, Ford and GM produced concept cars under the Clinton administration's Partnership for the Next Generation of Vehicles, and each used a diesel-electric hybrid powertrain to achieve the goal of building a five-passenger sedan that could reach 80 mpg.
Grade: C
Ready for prime time, but get ready to open your wallet, because a diesel hybrid could cost $10 grand more than an identical gas-powered car. Look for Mercedes to introduce the first diesel-electric hybrid in an S-Class sedan.
Turbochargers: Yeah, a turbocharger can make your slammed Civic rip off a 9.0-second quarter-mile. But it can also help boost the performance of a small engine when you need it, while allowing the powertrain to deliver better gas mileage the rest of the time.
The turbocharged Saturn Sky Red Line and Pontiac Solstice GXP actually deliver better gas mileage than the normally aspirated models, thanks to the use of a smaller-displacement engine and a taller final-drive ratio.
Grade: B-
The turbocharger is getting better all the time, but it still represents another layer of complexity and expense under the hood.
Direct Gasoline Injection: Here's the idea: Blast the gas directly into the combustion chamber instead of the intake ports, which helps the engine breathe better and extract more power from the fuel.
Direct gasoline injection bolsters the low- and midrange torque of the Mazda Direct Injection Spark Ignition (DISI) engine by 10 percent.
Grade: B-
Direct injection has helped improve fuel economy, and forthcoming generations of the technology will help even more, promises Udo Lindner, manager of powertrain development for BMW's 3 Series cars. But so far the benefit has fallen short of expectations. "We have found that with direct injection the power goes up much more rapidly than the efficiency," notes GM Vice Chairman Bob Lutz. "We would prefer that it were the other way around."
Cylinder Deactivation: If eight cylinders burn more gasoline than four, how about if you shut four of them off when you don't need that small-block V8 power? Chrysler, GM and Honda all are using the concept to idle unneeded cylinders under light loads.
The muscle-bound Chevy Impala SS V8 equipped with GM's Displacement-on-Demand cylinder-deactivation technology delivers an EPA-rated 27 mpg on the highway, just 1 mpg less than the rating of the similarly sized and powerful Lexus GS 450h V6 hybrid.
Grade: C+
In a vehicle equipped with this technology, it's virtually impossible to notice the change when half the cylinders go off line. At the same time, it's equally hard to notice an improvement at the gas pump. In both cases, a difference is there, but you'll only notice if you are looking for it.
Lightweight Materials: Lighter cars use less gas and go faster, so everyone is happy. But today's vehicles have to meet strict crash-safety requirements, and the expensive materials needed to lighten them are viable only in expensive cars.
New materials demand investment in research, as Mercedes-Benz discovered during a crash test of an early prototype S-Class when the high-strength steel shattered like glass. Mercedes had to spend some time to research the heat treatment and welding techniques, explains Hans Multhaupt, vice president of program management at Mercedes.
Grade: C
Advanced lightweight materials like the carbon-fiber roof for the BMW M6 and new M3 are cool, but the cost will limit their use.
Advanced Transmissions: Continuously variable transmissions and advanced six-, seven- and eight-speed automatics reduce the penalty for automatic gear selection.
A six-speed automatic transmission is about 5 percent more efficient than an old four-speed slushbox.
Grade: B-
Advanced transmissions help trim fuel consumption, but we've always been able to maximize mileage just by shifting for ourselves.
Gerbil Wheel: Still no word on the forced-induction gerbil-powered wheel, however, so we're going to have to fail this exciting bio-friendly technology until we have a chance to study it further.