How to Build a 100 Mile-Per-Gallon Car ... Right Now Read more: How to Build a 100 Mile-Per-Gallon Car ... Right Now - Popular Mechanics
Tuesday, July 19, 2011
, Posted by Unknown at 9:55 PM
With gas prices at historic highs, PM consults some of the best minds in automotive design and engineering on how to hit the next big milestone in fuel economy. Yes, a four-door that gets 100 mpg really is possible—today, with modern tech. Here's the plan.
Why can't the world's car companies make a vehicle that gets 100 mpg? Automotive technology keeps improving and people keep asking the question, but—as with fusion reactors and comprehensible phone bills—the reality always seems to be just a few years away. Sure, student engineers have achieved 2000 mpg in design contests, but those vehicles have been exercises in automotive minimalism, not practical everyday cars.
Steve Lapp, a professor from Ontario, says the moment has nearly arrived. "I've actually gotten over 100 mpg on some trips in my 2001 Toyota Prius," he says. The secret? He mounted solar panels on the car's roof to keep the batteries charged when the sun is shining. If Lapp, a backyard big thinker, can get triple-digit mileage occasionally, why can't the world's carmakers hit the mark on every drive?
Recently, they've come close—in Europe. The Volkswagen Lupo 3L turbodiesel and the Audi A2, which use the same engine, have both edged close to 80 mpg. That's better than a hybrid. On the downside, that amazing three-cylinder diesel doesn't meet U.S. emissions standards and the vehicles are Ringling Bros. size by American standards.
So the question remains: Could manufacturers deliver a practical car that a typical American family could use as daily transportation, getting 100 mpg or better on every single trip? We asked some of the most inventive engineering minds in the country. We looked at designs, materials and drivetrains. The answer? Yes, it can be done.
Taking the Weight Out
Fuel economy is all about efficiency. The lighter the load, the smaller and more efficient a car's powertrain can be. That saves fuel, and using a lighter engine saves yet more weight. Marc Ross, a University of Michigan physicist, suggests that—other things being equal—reducing the mass of a typical light-duty vehicle by 10 percent would increase the fuel economy by 7 percent. That's good, but dramatic mileage gains would demand hefty weight savings. Where to find them? While most cars today are made essentially of steel, some rely on lighter structural aluminum. That metal, however, presents manufacturing and repair challenges. The best choice for building a 100-mpg car would likely be a carbon-fiber composite, which can weigh less than half as much as steel. Carbon fiber is both expensive and hard to work with, but it offers an outstanding combination of light weight and strength. Carbon fiber is used extensively in motorsports and on exotic cars.
"If you look at exotics, they're all engineered for high performance. But you can apply the same type of technologies to meet fuel-economy goals," says Tadge Juechter, assistant chief engineer for Chevrolet Corvette.
Low-volume production of such large automobile structures is expensive—up to $100,000 per copy—according to Jon Fox-Rubin, president and CEO of Fiberforge, a leading manufacturer of advanced composite structures. Part of the price comes from manufacturing difficulties and a high rate of rejects, says Paul Williamsen, Toyota's product education manager: "You still have to pay for what gets thrown away." However, as the technology advances and volumes rise above 50,000 per year, the unit cost for carbon-fiber body structures could eventually drop to around $4000, low enough to make mass-market cars feasible.
GM's Ultralite showcar, built back in 1992 by Scaled Composites, the aerospace firm that later built SpaceShipOne, was a testament to the potential of advanced lightweight materials. Ultralite had a carbon-fiber-skin/PVC-core sandwich panel structure for the chassis and body panels. The structural weight, with doors, front and rear bumpers, and interior components, was only 420 pounds.
Weight savings can be found throughout a vehicle. Glass, for instance, is one of the heaviest components of an automotive body—heavier per square foot than the most commonly used steel. "Polycarbonate glazing will be coming into production within the next 10 years," Juechter says. The material is already used to cover headlights. For windows, a plasma process will be used to deposit a thin layer of glass on the polycarbonate, he says. "To an ice scraper or carwash it will look like glass, but you have a 50 percent weight reduction."
Engineers also can save weight by paring down the hardware needed to support the electronics so prevalent in modern vehicles. "There is so much cabling and wiring in vehicles today that it's not trivial, weightwise," says Deborah Hopkins, staff scientist at Lawrence Berkeley National Labs. Given the current state of electronics, it's possible to imagine a car without bulky hardware for audio, video and navigation. Instead, you'd have a thin screen with a port. "The cellphones of the near future would already carry these functions in them. There'd be a wireless connection to the display screen," says Richard Plavetich, technical design manager of Nissan Design America.
In contrast, "airbags and belts don't add as much weight as you might think," says Greg Thomas, a senior engineer at Honda R&D Americas. All the components of a modern restraint system weigh less than 25 pounds.
To get around the high costs of making components of magnesium, carbon fiber, light steel and other alloys, David E. Cole, chairman of the Center for Automotive Research in Ann Arbor, Mich., suggests a model in which, "instead of buying these raw materials, the owner leases them all and gets credit for returning the car for recycling."
Steve Lapp, a professor from Ontario, says the moment has nearly arrived. "I've actually gotten over 100 mpg on some trips in my 2001 Toyota Prius," he says. The secret? He mounted solar panels on the car's roof to keep the batteries charged when the sun is shining. If Lapp, a backyard big thinker, can get triple-digit mileage occasionally, why can't the world's carmakers hit the mark on every drive?
Recently, they've come close—in Europe. The Volkswagen Lupo 3L turbodiesel and the Audi A2, which use the same engine, have both edged close to 80 mpg. That's better than a hybrid. On the downside, that amazing three-cylinder diesel doesn't meet U.S. emissions standards and the vehicles are Ringling Bros. size by American standards.
So the question remains: Could manufacturers deliver a practical car that a typical American family could use as daily transportation, getting 100 mpg or better on every single trip? We asked some of the most inventive engineering minds in the country. We looked at designs, materials and drivetrains. The answer? Yes, it can be done.
Taking the Weight Out
Fuel economy is all about efficiency. The lighter the load, the smaller and more efficient a car's powertrain can be. That saves fuel, and using a lighter engine saves yet more weight. Marc Ross, a University of Michigan physicist, suggests that—other things being equal—reducing the mass of a typical light-duty vehicle by 10 percent would increase the fuel economy by 7 percent. That's good, but dramatic mileage gains would demand hefty weight savings. Where to find them? While most cars today are made essentially of steel, some rely on lighter structural aluminum. That metal, however, presents manufacturing and repair challenges. The best choice for building a 100-mpg car would likely be a carbon-fiber composite, which can weigh less than half as much as steel. Carbon fiber is both expensive and hard to work with, but it offers an outstanding combination of light weight and strength. Carbon fiber is used extensively in motorsports and on exotic cars.
"If you look at exotics, they're all engineered for high performance. But you can apply the same type of technologies to meet fuel-economy goals," says Tadge Juechter, assistant chief engineer for Chevrolet Corvette.
Low-volume production of such large automobile structures is expensive—up to $100,000 per copy—according to Jon Fox-Rubin, president and CEO of Fiberforge, a leading manufacturer of advanced composite structures. Part of the price comes from manufacturing difficulties and a high rate of rejects, says Paul Williamsen, Toyota's product education manager: "You still have to pay for what gets thrown away." However, as the technology advances and volumes rise above 50,000 per year, the unit cost for carbon-fiber body structures could eventually drop to around $4000, low enough to make mass-market cars feasible.
GM's Ultralite showcar, built back in 1992 by Scaled Composites, the aerospace firm that later built SpaceShipOne, was a testament to the potential of advanced lightweight materials. Ultralite had a carbon-fiber-skin/PVC-core sandwich panel structure for the chassis and body panels. The structural weight, with doors, front and rear bumpers, and interior components, was only 420 pounds.
Weight savings can be found throughout a vehicle. Glass, for instance, is one of the heaviest components of an automotive body—heavier per square foot than the most commonly used steel. "Polycarbonate glazing will be coming into production within the next 10 years," Juechter says. The material is already used to cover headlights. For windows, a plasma process will be used to deposit a thin layer of glass on the polycarbonate, he says. "To an ice scraper or carwash it will look like glass, but you have a 50 percent weight reduction."
Engineers also can save weight by paring down the hardware needed to support the electronics so prevalent in modern vehicles. "There is so much cabling and wiring in vehicles today that it's not trivial, weightwise," says Deborah Hopkins, staff scientist at Lawrence Berkeley National Labs. Given the current state of electronics, it's possible to imagine a car without bulky hardware for audio, video and navigation. Instead, you'd have a thin screen with a port. "The cellphones of the near future would already carry these functions in them. There'd be a wireless connection to the display screen," says Richard Plavetich, technical design manager of Nissan Design America.
In contrast, "airbags and belts don't add as much weight as you might think," says Greg Thomas, a senior engineer at Honda R&D Americas. All the components of a modern restraint system weigh less than 25 pounds.
To get around the high costs of making components of magnesium, carbon fiber, light steel and other alloys, David E. Cole, chairman of the Center for Automotive Research in Ann Arbor, Mich., suggests a model in which, "instead of buying these raw materials, the owner leases them all and gets credit for returning the car for recycling."
