Hybrids square off against diesels for the economy laurels
Light, ethereal, and nimble, the is the face of automotive technology that wears the halo. Drive me, it whispers, and you’ll get incredible fuel efficiency. You’ll accelerate smartly while burning less imported fuel.
Over there, wearing the horns, is the huge and brutal , which goes from 0 to 100 kilometers per hour (62 miles per hour) in 2.5 seconds and burns as much as 26.1 liters of gasoline to go 100 km. Drive me, it growls, and you can humble every other vehicle on the road. All you need is US $1.2 million.
Two road machines, for the soul and for the body, for Dr. Jekyll and for Mr. Hyde. Every other car today falls somewhere in between, a tradeoff between gas-guzzling darkness and environmental light. The dichotomy, sharp for a long time in much of Europe and Asia, became more so this past year in the United States, after Hurricane Katrina kicked gasoline prices briefly to $3 per gallon.
Nowadays, two technologies are battling for the halo. In one corner stand Japanese and U.S. companies, which have invested billions of dollars in hybrid-electric technology. In the other corner are European makers, with decades of experience in light-duty diesel engines.
Today’s hybrids cost so much to build that their fuel savings may not cover the higher sticker prices. They are most fuel-efficient in urban, stop-and-go traffic, and least economical at freeway speeds or under hard acceleration.
Diesels, on the other hand, tend to be dirty, and some of the air pollution standards they have to meet, such as those in California, are the world’s strictest. Yet the will to make a clean diesel is there, because the engines are so fuel-thrifty. When DaimlerChrysler AG drove a diesel version of its Mercedes-Benz ML sport-utility vehicle and the similar-sized Lexus RX400h hybrid from New York City to San Francisco this past August, the diesel achieved 9.1 L/100 km (26 mpg), while the hybrid got 10.2 L/100 km (23 mpg). Still, diesels, too, come at a price: U.S. consumers, unlike Europeans, pay as much or more for diesel fuel as for gasoline.
Technology is blooming not just under the hood but in the passenger compartment as well. Carmakers are falling all over themselves to accommodate the ubiquitous Apple iPod in their stereo systems. BMW is building high-definition radio into its flagship 7 Series. Several manufacturers have integrated live feeds of traffic news into their navigation systems. The Mazda Sassou concept car forgoes an ignition key for firmware burned into a USB device. Fiat SpA announced that all its models will soon have USB ports to handle, well, who knows? A video game? Camera? Printer? The mind boggles.
Last year’s single highest-tech car didn’t have an iPod or an HD radio. In fact, it didn’t even have a driver. In October, a bright blue Volkswagen Touareg sport-utility, nicknamed “Stanley,” navigated itself through a treacherous, 211-km (131-mile) course in California’s Mojave Desert in 6 hours, 54 minutes. By doing so, it captured for its creators a $2 million prize offered by the U.S. Defense Advanced Research Projects Agency, or DARPA, to promote the design of autonomous vehicles. Stanford University engineering students, helped by Volkswagen of America’s Electronics Research Laboratory in Palo Alto, Calif., included a camera and laser sensors in Stanley that fed data to six Pentium computers, which handled the engine and the steering. On the side of the vehicle, the cheeky students actually rewrote Volkswagen’s slogan, from “Drivers Wanted” to “Drivers Not Needed.”
Don’t look for self-driving cars in showrooms anytime soon. But do notice the small but significant milestones in that direction, such as the 2007 Lexus LS460 sedan, which will be able to park itself with minimal help from the person sitting in the driver’s seat. Unlike the human driver, it can’t be distracted by the iPod.
Concept Ford Reflex
A diesel hybrid that’s both sporty and green
Building on the theme that “small is big,” Ford Motor Co.’s highest-tech concept at January’s influential Detroit Auto Show was a subcompact sports car. It was a tad unusual for a company that earns much of its North American profit from midsize, large, and very large trucks and sport-utilities.
marries a small turbo-diesel, from Ford’s European Fiesta, to a refined version of the hybrid-electric drive system used in its Escape Hybrid sport-utility.
The basic obstacle to using a conventional diesel engine in a hybrid-electric drivetrain is the fact that both the diesel and the electric motor typically have lots of torque at low revolutions per minute (around 1500 to 3000). Generally, you want a fossil-fuel engine that delivers peak torque at relatively high rpms, so that when you combine it with the electric motor you get a curve of overall torque versus rpms that is fairly flat. Ford’s 1.4-liter turbocharged diesel engine fills the bill. It generates 41 kilowatts (55 horsepower) at 6000 rpm and 175 newton-meters (129 pound-feet) of torque at 4000 rpm.
According to Tom Watson, Ford’s hybrid systems propulsion manager, the little turbo diesel suits the parallel electric power system well. You might as well have a substantial electric motor, he points out, because a diesel’s high compression ratio—18:1 or more—demands a pretty beefy starter motor anyway. And by smoothing out the load on the diesel engine, the electric-drive system helps mightily in minimizing emissions of nitrogen oxides and particulates.
Both the engine and an electric motor of about 30 kW drive the front wheels through a six-speed transmission with electronic manual shifting. Like the Lexus RX400h luxury sport-utility hybrid, the Reflex uses an additional electric motor (of 15 kW) to drive the rear wheels and provide all-wheel drive. Ford quotes fuel economy of 5.9 to 3.6 L/100 km (40 to 65 mpg) but stresses that it is accompanied by sporty performance: acceleration from 0 to 60 mph (0 to almost 100 km/h) in less than 7 seconds.
Photovoltaic solar panels on the roof and in the lights help too, because even though they deliver “watts, not kilowatts,” as Watson says, they can lighten the load on the high-voltage batteries. Also, the panels power a small fan that vents heat from the car when it is parked.
If public response to a sporty high-mileage hybrid coupe is positive, Watson says, perhaps “the stigma of diesels in North America can be overcome by the hybrid’s image.”
2006 Chrysler 300C (Heritage Edition)
The most polite—and effective—headlights on U.S. roads
caught on fast after its U.S. introduction in the 2004 model year. It’s a powerful, stylish four-door sedan with a V8 engine driving the rear wheels—a genre that U.S. makers had ignored for 10 years while focusing on sport-utilities and light trucks. To improve fuel economy, an automatic control system shuts the valves to four of the eight cylinders when the load is light, giving it a rating of 13.1 and 9.0 L/100 km (18 and 26 mpg) in the U.S. Environmental Protection Agency’s city and highway driving simulations.
The really new technology this year comes up front, in the headlights. Called SmartBeam by developer Gentex Corp., of Zeeland, Mich., it switches on the high beams when needed, something U.S. drivers do only about 25 percent of the time. It’s a problem that a U.S. Department of Transportation study identified back in the 1960s. SmartBeam uses forward-facing CMOS image sensors, effectively a camera on a chip, built into the interior rearview mirror. The technology keeps the brights switched on until it detects either the headlamps of oncoming vehicles or the taillights of vehicles ahead, then switches to the low beams. To avoid distracting approaching drivers, the system fades the high beams on and off.
Interestingly, the first attempt at such control was made half a century ago, when diodes were big and fragile and programming was what you heard on the radio. The General Motors Autronic system (1952 to 1958) switched the high beams according to the light that reached a dashboard-mounted direct-current phototube—an anode and a light-sensitive cathode enclosed in a glass tube. This photocell increased current proportionally to the light that entered it. The job was not done well, but it is amazing that it was done at all.
Chrysler calls this car the Heritage Edition to commemorate the 50th year of its 300 series, famous particularly for the 1957 Chrysler 300C, renowned for its performance. Limited production of the US $36 000 Heritage Edition is scheduled to begin next month. The SmartBeam system was launched last year on luxury vehicles from General Motors Corp.’s Cadillac and Chrysler’s Jeep; it also will be fitted to BMW’s 5-, 6-, and 7-Series models in Europe.
2007 Chevrolet Tahoe/GMC Yukon
You’ve got mail. It’s from your car.
The latest Chevrolet Tahoe sport-utility and its twin are hardly examples of advanced automotive design. Their rear axles are live, rather than independently suspended as on virtually all European cars. Their V8 engines are refined versions of a decades-old design. And these sport-utilities are bigger and heavier than almost everything sold for passenger use in Japan or Europe. Like Japan’s kei cars, they’re designed for a specific use in a single country: hauling up to eight people and their luggage, even while towing as much as 3500 kilograms.
Tahoes and Yukons do offer advanced technology. One good example is their OnStar two-way wireless communications system. GM started the service in 1995 to connect vehicles to a remote service center, doing so automatically during emergencies. Its best-known feature alerts the Detroit monitoring center whenever an airbag deploys, whereupon OnStar calls local emergency services to check on the vehicle and its occupants.
Now GM has taken that connectivity a step further, to remind owners about maintenance. Starting last August, owners who used any nonemergency OnStar function were reminded of outstanding recall notices—which they also receive through the mail—and were connected to dealers to schedule a repair visit. Beginning this past January, OnStar’s central computers began e-mailing owners to remind them of upcoming maintenance tasks like oil changes and to confirm that the vehicle’s safety systems are working properly.
The OnStar system consists of a digital cellular telephone built into the vehicle’s audio system, along with a six-channel Global Positioning System receiver that continuously pinpoints its location. OnStar monitors dozens of functions with sensors that collect data on acceleration, braking, steering angles, body roll, oil pressure, gasoline level, and more. It can also detect when a vehicle is being driven “too aggressively” by comparing a car’s performance data to its norms. If OnStar deems the car’s on-road activities too extreme, it calls the driver to make sure everything’s all right.
2006 Subaru R2 Type S
A teeny-weeny screaming road machine
Japan’s tiny kei cars, unknown in the United States and rarely seen in Europe, were created in response to laws that give owners reduced taxes and insurance costs and—best of all, in Japan’s crowded cities, anyway—free parking. To qualify, a car must be no more than 3.4 meters long, 2 meters high, and 1.48 meters wide, and its engine may displace no more than 0.66 liters, or 660 cubic centimeters, and produce no more than 47 kilowatts (63 horsepower).
Daihatsu, Honda, Mazda, Mitsubishi, Subaru, and Suzuki sell kei cars, and many offer high-performance versions that pack nearly as much advanced technology per cc as the gargantuan Bugatti Veyron 16.4 (see Endnote). The best of the bunch is , newly revised for 2006, because it alone blends all-wheel drive with a continuously variable transmission (CVT).
Normally, a CVT’s control logic optimizes engine efficiency by automatically adjusting the gearing ratio to engine speed. But Subaru has included a seven-speed “manumatic” shifter that is operated by tapping “paddles” behind the steering wheel to shift up or down. It lets the driver simulate controlling the transmission manually—an odd trick with a continuously variable transmission. Of course, the intervention by mere mortals will compromise efficiency and waste fuel, but so what? This little car wasn’t designed for ultra-economy but for storming Japan’s congested urban streets.
At 658 cc, the engine comes about a teaspoon under the allowed displacement. Unlike some of its kei competitors, it has not three cylinders but four, with four valves per cylinder controlled by dual overhead cams. Alone in the group, it uses a supercharger—a mechanical pump driven off the engine’s crankshaft—to cram air into the engine’s cylinders. To pack even more in, the Type S engine has an intercooler, a radiatorlike device to cool the air and thus increase its density.
Because most kei cars provide as much power as Japanese law allows, they compete on torque and acceleration. At 3200 revolutions per minute, the Type S generates 103 newton-meters (76 pound-feet), close to the current class champion’s 110 Nm (81 lb-ft). Its 47 kW (63 hp) is produced at 6000 rpm, typical for the class. It accelerates from 0 to 100 km/h (62 mph) in roughly 10 seconds and tops out at 160 km/h (99 mph), best among these tiny cars. It uses 5.6 L/100 km (42 mpg) on the Japanese emission standard cycle to propel its total weight of 880 kilograms (1940 pounds). Lesser kei cars with hybrid electric drive—sans turbos, all-wheel drive, and the rest—can achieve up to 3.1 L/100 km (78 mpg), but they pay the price: some take as long as 16.5 seconds to get from 0 to 100 km/h.
2007 Mercedes-Benz E 320 Bluetec
The cleanest diesel engine in the world
In the United States, diesel engines still call up images of roaring 18-wheelers at best—and smoky, unreliable 1980s Oldsmobiles at worst. In Europe, on the other hand, more than half of all passenger cars sold have diesel engines, and some of them are among the best appointed and most prestigious in their lines. But those diesels can’t be brought across the Atlantic, because the United States puts far more stringent controls on emissions, and because the cleaner diesel fuel widely available in Europe hasn’t yet reached U.S. pumps. The few diesel vehicles now sold in the United States by Mercedes-Benz, Volkswagen, and Jeep are available in 45 states. But of the five states where you can’t get them, two are auto-market whoppers: California (which has ultrastrict emission standards) and New York (which, like three other Northeastern states, has adopted the California standards).
To make the grade, Mercedes-Benz developed the . In its basic form it scrubs the exhaust in no fewer than three catalytic converters. First, an oxidizing converter treats hydrocarbons and carbon monoxide in the exhaust. Second, a new DeNOx storage catalytic converter adsorbs nitrogen oxides (NOx) on the surface of the many fine grains of activated carbon of a filter; later, that stored NOx is flushed out and shunted back into the combustion process, where it is largely decomposed. Meanwhile, troublesome particulates collect on a filter hot enough to burn them away, so that nobody ever has to clean the thing. Finally, a third catalytic converter cleans the treated exhaust further in a process known as selective catalytic reduction.
A more complex form of Bluetec replaces the DeNOx (stage two) converter with a system that injects liquid urea into the exhaust gas, where it releases ammonia, allowing the final catalyst to convert NOx into nitrogen and water. The car comes with a 20-liter tank of urea that is designed to last for 207 000 kilometers (roughly 12 000 miles)—long enough, Mercedes says, to leave the refilling of the tank for scheduled maintenance at the dealership.
The treatment cuts NOx emissions by up to 80 percent over the E 320 CDI, an IEEE Spectrum Top 10 Tech Car last year.
The E 320 Bluetec’s 155-kilowatt (208-horsepower) 3.0-L turbocharged V6 diesel engine develops 540 newton-meters (398 pound-feet) of torque—equivalent to that of a V8—but uses just 6.7 L to go 100 km (35 mpg), to propel a vehicle that weighs about 1750 kilograms (about 3860 pounds).
Bluetec’s scrubber depends on exhaust gas that is pretty clean to begin with, thanks to an optimized combustion process. Electronic controls coordinate the operation of each cylinder’s four valves, a high-pressure system that injects fuel into the cylinders at 159 000 kilopascals (about 23 000 pounds per square inch), a turbocharger that crams in air and, finally, a system that recirculates exhaust gas back into the engine. Sometimes, the system injects a little fuel into the exhaust gas before it reaches the particulate filter, setting up an “afterburner” to keep the filter hot enough.
Bluetec requires the cleaner form of diesel fuel that won’t be available in the United States until the end of this year. It cuts the sulfur content to 15 parts per million from the previous U.S. limit of 500. Sulfur is a main component of particulates, which have recently been implicated in respiratory problems common in urban areas.
The simpler (nonurea) version of Bluetec is slated to go on sale in the United States in the E 320 this fall, at a price that remains to be set. Mercedes plans to offer a system incorporating urea injection in a version of its GL large sport-utility later in the 2007 model year.
2007 Lexus LS460
A salvo of advanced automotive electronics...and much more
From its beginning in 1989, Toyota Motor Corp.’s Lexus has offered luxury, performance, handling, and reliability, all at a price the European leaders couldn’t match. Today, a five-year-old Lexus generally has fewer problems than a brand-new Mercedes or BMW, and it is the leading U.S. luxury brand. Now Toyota is taking it global, expanding Lexus sales into Europe and Asia.
This year Lexus took off the gloves, releasing a feature not found on any German or U.S. competitor. The system parks the car at the touch of a button, with just a little braking on the driver’s part. It is used during parallel parking or backing into a garage. Once the driver specifies the parking spot on the vehicle’s navigation system, it processes images from front and rear cameras and uses the results to control both electric power steering and the “drive-by-wire” electronic throttle. It works so well it’s spooky.
The similar Intelligent Parking Assist system has been an option on Japanese-market Toyota Priuses for two years, priced at US $2000 in Japan and $700 in the United Kingdom. That system, however, requires the driver to operate the accelerator as well as the brakes while the car steers. But pioneering the system in the United States—where new product features sometimes lure lawyers like flies—speaks to Toyota’s confidence that its software is bulletproof. Lexus is withholding the technological details for release at Geneva’s 76th International Auto Show, in March (after press time for this issue).
In case anyone missed the challenge to other luxury-car makers in general and Mercedes in particular, the will have the world’s first automatic transmission with eight gears—one more than the record-setting transmission that Mercedes proudly unveiled in 2003.
The car’s 4.6-liter V8 engine generates 502 newton meters (370 pound-feet) of torque and 283 kilowatts (3807nbsp;horsepower)—36 percent more power than its predecessor. It’s enough to kick the LS from 0 to 60 mph in 5.4 seconds while delivering city and highway fuel mile-age estimated at 9.4 and 8.7 L/100 km (25 and 27 mpg). And, oh yes, a hybrid version will be introduced in April.
The car’s electronics are an alphabet soup of control and assist systems. The Vehicle Dynamics Integrated Management (VDIM) system mines data from a variety of systems to anticipate skidding and helps the driver recover with electronically controlled brakes; electronic power steering; vehicle stability control; antilock brakes; braking assist; electronic brake-force distribution; and engine torque, based on inputs from dozens of sensors—and the driver, of course.
Other tech firsts include individual DVD players for each of the three passenger spots. The discrete 5.1 surround-sound stereo system developed by Mark Levinson features 19 speakers. Real-time traffic updates are integrated into the navigation computer. The climate-control system adjusts itself based on measurements of not only the ambient temperature in various cabin zones but also of the body heat emanating from each occupant.
The luxury-to-dollar ratio is going to take a big leap in autumn, when this über-Lexus rolls out.
2006 Volkswagen Passat
Even mass-market cars get seriously sophisticated
Not long ago, the base model of a popular midsize sedan was a grim place to be. There was a small engine, a bare-bones gearbox, large expanses of vinyl or plain-cloth upholstery, and maybe an AM radio.
Those days are gone. Consider the new, sixth generation of the , sold in the United States as a sports sedan and available throughout Europe with no fewer than eight different engine choices—three diesel and five gasoline.
The entry-level Passat for the United States is a 16-valve 2.0-liter double-overhead-camshaft inline four. It has a turbocharger, which uses hot exhaust gas to drive a pump that compresses air, an intercooler to increase the air’s density, and high-pressure fuel injectors to squirt vaporized gasoline into the cylinder. The result is 149 kilowatts (200 horsepower) at 5100 revolutions per minute and a remarkably flat torque curve of 280 newton-meters (207 pound-feet) from 1800 to 5000 rpm, for plenty of pulling power. The standard gearbox is a six-speed manual.
Then there’s the optional 3.6-L engine, Volkswagen’s characteristic VR6, with two banks of three cylinders each in a narrow V shape at an angle of just 10.6 degrees, making it both light and compact. It produces 206 kW (280 hp) at 6200 rpm, but its maximum torque of 360 Nm (265 lb-ft) comes at just 2750 rpm. Mated to the VR6 is a six-speed automatic transmission that also lets the driver shift manually. VW’s 4Motion all-wheel drive is available as well.
Inside, the car has eight air bags as standard: two in front, four front- and rear-side curtains, and two front-side thorax protectors. Two rear-side thorax protectors come as an option. Other safety features include seat-belt pretensioners, which better restrain occupants by drawing the belts taut when the car senses an accident, and antilock brakes coupled with an engine braking system. The power steering not only varies the degree of assist with speed and other factors but also helps the driver maintain a straight-ahead path by steering into deflections from side winds and road irregularities. And an electronic stabilization program monitors speed, cornering, braking, inputs from the drive-by-wire throttle, and other data to compensate for slipping traction or sliding tires faster and more precisely than the driver can.
Despite the technology, the Passat is light on its tires, weighing from 1499 to 1737 kilograms (3305 to 3829 pounds), depending on options, with a 0-to-60 time ranging from 6.2 to 6.9 seconds.
Some attractive features offered in the European Passats aren’t available in the United States. Among them are bixenon headlamps that swivel as much as 15 degrees to illuminate the direction in which the car is turning, and adaptive cruise control that uses radar sensing to detect slower vehicles ahead and stay a set distance behind them. The same radar also senses critical proximity situations and prepares the Passat for an emergency by moving the brake pads closer to the disks and increasing brake sensitivity to make sudden braking more effective.
2006 Volvo s60
Electronic vision unblocks the “blind spot”
It’s every driver’s nightmare: you change lanes suddenly, glancing in the rearview mirror without looking over your shoulder...and you merge directly into a car hidden in one of your car’s blind spots. The U.S. National Highway Traffic Safety Administration says that “lane change situations” are involved in 4 to 10 percent of all car crashes.
Three years ago, set out to create a system that would warn drivers when other vehicles entered their blind spots. The result, the Blind-spot Information System (BLIS), was recently offered as a $770 option on S60 and S80 sedans, V70 wagons, and XC90 sport-utilities sold in European markets. Volvo expects to offer the system eventually in all its cars.
Two camera modules, one for each door mirror, capture images in a low-resolution black-and-white CMOS video sensor, behind glass that is heated, to clear away fog. The camera, trained on the side rear area of the car, processes 25 images per second in a signal-processing chip, which uses software stored in the camera’s flash memory. A control processor supervises I/O, data transfer, and communication among the components.
Say a vehicle enters one of your car’s blind spots. Standard vision-motion tracking algorithms recognize the intruder, the camera module sends an alarm signal along a bus, and an LED mounted near the door’s mirror starts to flash. At the same time, a status message appears on a dashboard screen.
The challenge, says Lex Kerssemakers, Volvo’s head of product planning, was in figuring out how to distinguish cars from background conditions under a variety of light levels, sun angles, weather conditions, vehicle speeds, traffic scenarios, road types, and architectural surroundings. The system also has to account for speed differentials, because a vehicle traveling at precisely the same speed as one’s own can lurk in a blind spot for a while. A particular problem during development, Kerssemakers adds, was posed by the shadows cast by roadside light when the sun is close to the horizon. Early systems generated many false positives—warnings of nonexistent hazards. Although that has been corrected, the system deliberately errs slightly on the side of caution, he says.
Volvo emphasizes that the technology is meant to support proper driving habits rather than substitute for them. But Kerssemakers concedes that the company engineered the system on the assumption that lazy drivers will in fact rely on the system alone. Drivers can switch off the system if they wish, but it is switched back on every time the car is started.
After going back to a car without BLIS, Kerssemakers says he missed the system—“and it wasn’t just me; all our test drivers missed having the light to warn them.”
Mitsubishi Concept-CT MIEV
A whole new meaning for “hot wheels”
, styled at Mitsubishi Motors Design Center in Cypress, Calif., is a window to an intriguing future of partially electric drivetrains. This compact four-door hatchback, just 3.8 meters (150 inches) long, deploys four electric motors on the wheels themselves, rather than the usual plan, which is to use one or two central motors delivering power to driveshafts. The Mitsubishi In-wheel Motor Electric Vehicle (MIEV) system is mated to a three-cylinder, 1.0-liter gasoline engine located behind the rear seat but ahead of the rear axle line, a “rear-midship” layout typically used in sports cars for its low center of gravity and marvelously quick steering response.
Notwithstanding the innovative power train, the Concept-CT doesn’t actually run. Why? Well, concept cars range from pure styling mock-ups to fully engineered vehicles just a hair away from production. The CT is closer to the mock-up. The key components are all there to show they fit and can function within the structure, size, and shape of the vehicle envisioned. It’s an important first step toward a “real” car, whether it winds up looking like the CT or not.
The power train used in the CT develops 100 kilowatts (134 horsepower) in total, half coming from the small gasoline engine, the rest from a lithium-ion battery pack. The engine would drive the rear wheels through a transmission that also cranks a 40-kW (54-hp) generator, which recharges the batteries together with power recovered during braking. Because each of four 20-kW (27-hp) wheel motors is individually powered by the car’s control electronics, the system offers all-wheel drive while losing the differentials, with their weight and bulk—thus making possible a flat floor for the passenger compartment. The designers also found an ingenious solution to a difficult problem: how do you cool an engine that sits behind the rear passenger seats? Answer: they put a scoop in the roof to channel air through the car’s pillars to the engine.
The CT’s four electric motors are experimental units that feature a hollow-doughnut construction, in which the rotor goes outside the stator instead of inside it, conserving space and reducing weight. It’s a crucial feature, because putting a more conventional motor in every wheel can double its “unsprung weight,” that is, the mass of the wheel and hub whose movement the suspension must smoothly accommodate.
Mitsubishi’s goal, the company says, is to launch a production model incorporating MIEV technology and lithium-ion batteries by 2010. As a step in that direction, Mitsubishi is road-testing the MIEV power train in a modified Lancer Evo rally car, its fastest and best-known performance vehicle.
Subaru B5-TPH (Turbo Parallel Hybrid)
An opposing take on performance hybrids
The first hybrids were designed to save fuel. More recently, some designs have begun trading fuel economy for performance. Now Subaru, which usually does things differently, offers both qualities in one package. It has added a hybrid electric drive to a turbocharged gasoline engine, proposing a compact power train that’s as muscular as the company’s standard turbo engine but burns 30 percent less fuel. The concept vehicle, first shown at the 39th Tokyo Motor Show last fall, is a running demonstration of that technology.
It starts with a turbocharged 2.0-liter version of the company’s highly regarded horizontally opposed “boxer” engine, generating 191 kilowatts (256 horsepower) and 342 newton-meters (252 pound-feet) of torque. The engine uses the Miller combustion cycle, which leaves the intake valves partially open at the start of the compression stroke. This scheme saves energy by letting the turbocharger do some of the compression work that would otherwise have to be done by the pistons. However, at lower engine speeds, at which the turbocharger generates less pressure, the Miller-cycle engine design produces less torque.
To overcome that drawback, Subaru engineers added an electric motor-generator, just 58 millimeters thick, between the engine and the transmission. Electric motors deliver maximum torque as soon as they start up, so the hybrid system neatly offsets the characteristic “turbo lag” that causes the Miller cycle’s low-speed sluggishness. Operating as a motor, the motor-generator produces just 10 kW (13 hp) at peak power but a full 150 Nm (111 ft-lb) of torque.
Subaru is adapting hybrid technology for a variety of engines, transmissions, and vehicle configurations. For instance, it has designed the torque converter to make it possible to fit the electric motor within an existing transmission housing. It delivers power through an automatic transmission to Subaru’s signature all-wheel-drive system, which varies torque to each wheel according to changes in road conditions. Because performance, not just fuel economy, is a goal, both the motor and the engine operate all the time. The scheme allows for an electric motor much smaller than what you’d have to put in a hybrid that could run off the motor alone. The entire hybrid package adds just 100 kilograms (220 pounds) of weight. Batteries are recharged both from engine power and through regenerative braking.
The B5-TPH shows off another hybrid first: Subaru’s manganese lithium-ion batteries, developed in a joint venture between Fuji Heavy Industries Ltd. (Subaru’s parent) and NEC Corp., both in Tokyo. With 50 percent greater power density than the nickel-metal-hydride batteries used for hybrids today, lithium-ion batteries also offer much faster recharges. Subaru and NEC hint, without giving any supporting details, that they have solved lithium ion’s two main weak spots: excessive heat and a limited number of recharging cycles.
The B5-TPH itself is a sporty two-seat, all-wheel-drive grand tourer with a clamshell hatch at the rear. It has elements of a coupe, a sporty hatchback, and a sport-utility. As in Subaru’s World Rally Championship cars, the compact turbo boxer engine lowers the center of gravity for better handling. Aggressively treaded tires on 480-mm (19-inch) alloy wheels and 200 mm (8 inches) of ground clearance fit out the B5-TPH for light-duty, off-road travel. The TPH power train is scheduled to be released in a version of Subaru’s Legacy sedan in Japan in 2007.
1000 horsepower. Any questions?
It has the luxury of a Rolls-Royce, the performance of a Formula One car, and the drivability of a Honda. It’s a combination that leaves the Mercedes-Benz SLR McLaren, the Ferrari Enzo, and other wannabes in the dust.
The Bugatti Veyron 16.4 is the fastest, most powerful, most expensive production car in the history of the automotive industry. Its 8.0-liter 16-cylinder engine has four turbochargers and produces 740 kilowatts (1001 metric horsepower, or 987 hp). And you want torque? How does 1250 newton-meters sound? The car reaches 1007 km/h in 2.5 seconds from a standing start, and 300 km/h (186 mph) in 16.7 seconds. It has a top speed of 408 km/h (254 mph). And each Veyron costs a flat ¤1 million, or about US $1.2 million, plus tax.
The structure is made of carbon fiber and aluminum. The brakes are carbon ceramic, and the exhaust system is titanium. There are 10 radiators to dissipate the engine’s heat. To keep the car on the ground when its winglike shape develops lift at high speeds, there are front and rear air diffusers and a massive rear spoiler that deploys electronically to generate a drag force of 0.6 times the force of gravity. Ride height varies with speed from 125 to 66 mm.
To go beyond 375 km/h (233 mph), the driver must stop the car, insert a special key, and go through a checklist (“Seatbelts, check; oil, check; last will and testament, check”). At top speed, the Veyron runs through a full tank of gas in 12 minutes, for a fuel economy measured in gallons per mile. The U.S. Environmental Protection Agency rates it at 9 and 18 mpg in normal city and highway cycles (26.1 and 13.1 L/100 km). Presumably, though, mileage won’t be a factor in anyone’s purchase of this vehicle, ever. From 400 km/h, the car can stop in 10 seconds, covering more than a kilometer while doing so.
In the rarefied world of the supercar, so-called volume production is measured in hundreds, sometimes just dozens of cars. By that standard, the 300 examples of the Veyron 16.4 that Bugatti Automobiles SAS, of Molsheim, France, expects to build—50 per year—qualify it as a volume car.
Bugatti built just 7000 cars between 1909 and 1956, from Grand Prix winners to the legendary Royale ultraluxury car. It seems the greatest of ironies that the storied French marque was revived by Volkswagen, the German “people’s car” maker. A pet project of former chairman Ferdinand Piëch, the development of the Veyron took eight years. Industry analysts don’t expect the company to recoup its investment.
But what a glorious piece of engineering it is. Volkswagen should be proud. Perhaps even Ettore Bugatti, a man of immense flamboyance, ego, and engineering genius, would be pleased.
About the Author
John Voelcker has written about automotive technology, home building, and other topics for 20 years. He covered software and microprocessor design for IEEE Spectrum from 1985 to 1990. A connoisseur of vintage British automobiles, he has owned five Riley One-Point-Fives, four Morris Minors, three Pontiac GTOs, and a handful of Subarus.