34 IEEE Spectrum | April 2006 | NA www.spectrum.ieee.org
Hybrids square off against diesels for the economy laurels
BY JOHN VOELCKER
L ight, ethereal, and nimble, the 2006 Subaru R2 Type S is the face of automotivetechnology that wears the halo. Drive me, it whispers, and youll get incrediblefuel efficiency. Youll accelerate smartly while burning less imported fuel.Over there, wearing the horns, is the huge
and brutal Bugatti Veyron 16.4, which goes from0 to 100 kilometers per hour (62 miles per hour)in 2.5 seconds and burns as much as 26.1 litersof gasoline to go 100 km. Drive me, it growls,and you can humble every other vehicle on theroad. All you need is US $1.2 million.
Two road machines, for the soul and for thebody, for Dr. Jekyll and for Mr. Hyde. Every
other car today falls somewhere in between, atradeoff between gas-guzzling darkness andenvironmental light. The dichotomy, sharp fora long time in much of Europe and Asia, becamemore so this past year in the United States, afterHurricane Katrina kicked gasoline prices brieflyto $3 per gallon.
Nowadays, two technologies are battling forthe halo. In one corner stand Japanese and U.S.
definition radio into its flagship 7 Series.Several manufacturers have integrated livefeeds of traffic news into their navigation sys-tems. The Mazda Sassou concept car forgoesan ignition key for firmware burned into a USBdevice. Fiat SpA announced that all its mod-els will soon have USB ports to handle, well,who knows? A video game? Camera? Printer?The mind boggles.
Last years single highest-tech car didnthave an iPod or an HD radio. In fact, it didnteven have a driver. In October, a bright blueVolkswagen Touareg sport-utility, nicknamedStanley, navigated itself through a treacher-ous, 211-km (131-mile) course in CaliforniasMojave Desert in 6 hours, 54 minutes. By doingso, it captured for its creators a $2 million prizeoffered by the U.S. Defense Advanced ResearchProjects Agency, or DARPA, to promote thedesign of autonomous vehicles. Stanford Uni-versity engineering students, helped by Volks-wagen of Americas Electronics ResearchLaboratory in Palo Alto, Calif., included a cam-era and laser sensors in Stanley that fed datato six Pentium computers, which handled theengine and the steering. On the side of thevehicle, the cheeky students actually rewroteVolkswagens slogan, from Drivers Wantedto Drivers Not Needed.
Dont look for self-driving cars in showroomsanytime soon. But do notice the small but sig-nificant milestones in that direction, such as the2007 Lexus LS460 sedan, which will be able topark itself with minimal help from the personsitting in the drivers seat. Unlike the humandriver, it cant be distracted by the iPod.
2006 SUBARU R2 TYPE S
BUGATTI VEYRON 16.4
companies, which have invested billions of dol-lars in hybrid-electric technology. In the othercorner are European makers, with decades ofexperience in light-duty diesel engines.
Todays hybrids cost so much to build thattheir fuel savings may not cover the highersticker prices. They are most fuel-efficient inurban, stop-and-go traffic, and least economicalat freeway speeds or under hard acceleration.
Diesels, on the other hand, tend to be dirty,and some of the air pollution standards theyhave to meet, such as those in California, arethe worlds strictest. Yet the will to make a cleandiesel is there, because the engines are so fuel-thrifty. When DaimlerChrysler AG drove adiesel version of its Mercedes-Benz ML sport-utility vehicle and the similar-sized LexusRX400h hybrid from New York City to SanFrancisco this past August, the diesel achieved9.1 L/100 km (26 mpg), while the hybrid got 10.2 L/100 km (23 mpg). Still, diesels, too, comeat a price: U.S. consumers, unlike Europeans, payas much or more for diesel fuel as for gasoline.
Technology is blooming not just under thehood but in the passenger compartment as well.Carmakers are falling all over themselves toaccommodate the ubiquitous Apple iPod intheir stereo systems. BMW is building high-
HELL ON WHEELS: At top speed, the Bugatti Veyron 16.4runs through a full tank of gas in 12 minutes.
LITTLE ANGEL: The Subaru R2 Type S packs a lot of tech,including a supercharger and an intercooler, into a tiny space.
36 IEEE Spectrum | April 2006 | NA www.spectrum.ieee.org
Building on the theme that "small is big,"Ford Motor Co.s highest-tech conceptat Januarys influential Detroit AutoShow was a subcompact sports car. Itwas a tad unusual for a company thatearns much of its North American profitfrom midsize, large, and very largetrucks and sport-utilities.
The Reflex marries a small turbo-diesel, from Fords European Fiesta, to arefined version of the hybrid-electricdrive system used in its Escape Hybridsport-utility.
The basic obstacle to using a conven-tional diesel engine in a hybrid-electricdrivetrain is the fact that both the dieseland the electric motor typically have lotsof torque at low revolutions per minute(around 1500 to 3000). Generally, youwant a fossil-fuel engine that deliverspeak torque at relatively high rpms, sothat when you combine it with the elec-
tric motor you get a curve of overalltorque versus rpms that is fairly flat.Fords 1.4-liter turbocharged dieselengine fills the bill. It generates 41 kilo-watts (55 horsepower) at 6000 rpm and175 newton-meters (129 pound-feet) oftorque at 4000 rpm.
According to Tom Watson, Fordshybrid systems propulsion manager, thelittle turbo diesel suits the parallel electricpower system well. You might as well havea substantial electric motor, he points out,because a diesels high compressionratio18:1 or moredemands a prettybeefy starter motor anyway. And bysmoothing out the load on the dieselengine, the electric-drive system helpsmightily in minimizing emissions of nitro-gen oxides and particulates.
Both the engine and an electric motorof about 30 kW drive the front wheelsthrough a six-speed transmission with
electronic manual shifting. Like the LexusRX400h luxury sport-utility hybrid, theReflex uses an additional electric motor(of 15 kW) to drive the rear wheels andprovide all-wheel drive. Ford quotes fueleconomy of 5.9 to 3.6 L/100 km (40 to65 mpg) but stresses that it is accompa-nied by sporty performance: accelerationfrom 0 to 60 mph (0 to almost 100 km/h)in less than 7 seconds.
Photovoltaic solar panels on the roofand in the lights help too, because eventhough they deliver "watts, not kilowatts,"as Watson says, they can lighten the loadon the high-voltage batteries. Also, thepanels power a small fan that vents heatfrom the car when it is parked.
If public response to a sporty high-mileage hybrid coupe is positive, Watsonsays, perhaps "the stigma of diesels inNorth America can be overcome by thehybrids image."
A diesel hybrid thats both sporty and green
WINGING IT: Ford's innovation-packed Reflex sports carconcept has back-hingedswing-wing doors.
TOP 10 TECH CARS
Chryslers 300C caught on fast after its U.S. introduction inthe 2004 model year. Its a powerful, stylish four-door sedanwith a V8 engine driving the rear wheelsa genre that U.S.makers had ignored for 10 years while focusing on sport-utilitiesand light trucks. To improve fuel economy, an automaticcontrol system shuts the valves to four of the eight cylinderswhen 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 Agencyscity and highway driving simulations.
The really new technology this year comes up front, in the head-lights. 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. Its a problem that aU.S. Department of Transportation study identified back in the1960s. SmartBeam uses forward-facing CMOS image sensors, effec-tively a camera on a chip, built into the interior rearview mirror.The technology keeps the brights switched on until it detects eitherthe headlamps of oncoming vehicles or the taillights of vehiclesahead, then switches to the low beams. To avoid distractingapproaching drivers, the system fades the high beams on and off.
Interestingly, the first attempt at such control was made halfa century ago, when diodes were big and fragile and programmingwas what you heard on the radio. The General Motors Autronic sys-tem (1952 to 1958) switched the high beams according to the lightthat reached a dashboard-mounted direct-current phototubean anode and a light-sensitive cathode enclosed in a glass tube. This
photocell increased currentproportionally to the
light that entered it.
The job was not donewell, 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 per-formance. Limited production of the US $36 000 Heritage Edition is sched-uled to begin next month. The SmartBeam system was launched last yearon luxury vehicles from General Motors Corp.s Cadillac and Chryslers Jeep;it also will be fitted to BMWs 5-, 6-, and 7-Series models in Europe.
The most politeand effectiveheadlights on U.S. roads
Youve got mail. Its fromyour car.The latest Chevrolet Tahoe sport-utility and itsGMC Yukon twin are hardly examples of advancedautomotive design. Their rear axles are live, ratherthan independently suspended as on virtually allEuropean cars. Their V8 engines are refined versionsof a decades-old design. And these sport-utilities arebigger and heavier than almost everything sold forpassenger use in Japan or Europe. Like Japans keicars, theyre designed for a specific use in a singlecountry: hauling up to eight people and their lug-gage, even while towing as much as 3500 kilograms.
Tahoes and Yukons do offer advanced technol-ogy. One good example is their OnStar two-waywireless communications system. GM started theservice in 1995 to connect vehicles to a remoteservice center, doing so automatically during emer-gencies. Its best-known feature alerts the Detroitmonitoring center whenever an airbag deploys,whereupon OnStar calls local emergency serv-ices to check on the vehicle and its occupants.
Now GM has taken that connectivity a stepfurther, to remind owners about maintenance.Starting last August, owners who used any non-emergency OnStar function were reminded ofoutstanding recall noticeswhich they alsoreceive through the mailand were connected todealers to schedule a repair visit. Beginning thispast January, OnStars central computersbegan e-mailing owners to remind them ofupcoming maintenance tasks like oil changesand to confirm that the vehicles safety sys-tems are working properly.
The OnStar system consists of a digital cellulartelephone built into the vehicles audio system, alongwith a six-channel Global Positioning Systemreceiver that continuously pinpoints its location.OnStar monitors dozens of functions with sensorsthat collect data on acceleration, braking, steeringangles, body roll, oil pressure, gasoline level, andmore. It can also detect when a vehicle is beingdriven "too aggressively" by comparing a carsperformance data to its norms. If OnStar deems thecars on-road activities too extreme, it calls the driverto make sure everythings all right.
www.spectrum.ieee.org April 2006 | IEEE Spectrum | NA 37
BRIGHT IDEA: Head-lights on the Chrysler300C can switch auto-matically between thehigh and low beams.
CAR CONNECTIVITY: The OnStarsystem reminds owners ofvehicles like thisYukon about necessary maintenance.
In the United States, diesel engines stillcall up images of roaring 18-wheelers atbestand smoky, unreliable 1980s Olds-mobiles at worst. In Europe, on the otherhand, more than half of all passenger carssold have diesel engines, and some of themare among the best appointed and mostprestigious in their lines. But those dieselscant be brought across the Atlantic,
because the United States puts far morestringent controls on emissions, andbecause the cleaner diesel fuel widelyavailable in Europe hasnt yet reached U.S.pumps. The few diesel vehicles now soldin the United States by Mercedes-Benz,Volkswagen, and Jeep are available in45 states. But of the five states where youcant get them, two are auto-marketwhoppers: California (which has ultrastrictemission standards) and New York (which,like three other Northeastern states, hasadopted the California standards).
To make the grade, Mercedes-Benzdeveloped the Bluetec diesel engine. In
its basic form it scrubs the exhaust inno fewer than three cat-
alytic converters. First,
an oxidizing converter treats hydrocarbonsand carbon monoxide in the exhaust.Second, a new DeNOx storage catalyticconverter adsorbs nitrogen oxides (NOx)on the surface of the many fine grains ofactivated carbon of a filter; later, that storedNOx is flushed out and shunted back intothe combustion process, where it is largelydecomposed. Meanwhile, troublesomeparticulates collect on a filter hot enoughto burn them away, so that nobody everhas to clean the thing. Finally, a thirdcatalytic converter cleans the treatedexhaust further in a process known asselective catalytic reduction.
A more complex form of Bluetecreplaces the DeNOx (stage two) converterwith a system that injects liquid urea intothe exhaust gas, where it releases ammo-nia, allowing the final catalyst to convertNOx into nitrogen and water. The carcomes with a 20-liter tank of urea thatis designed to last for 20 000 kilometers(roughly 12 000 miles)long enough,Mercedes says, to leave the refilling ofthe tank for scheduled maintenance atthe dealership.
The treatment cuts NOx emissions byup to 80 percent over the E 320 CDI, anIEEE Spectrum Top 10 Tech Car last year.
The E 320 Bluetecs 155-kilowatt(208-horsepower) 3.0-L turbocharged V6diesel engine develops 540 newton-meters (398 pound-feet) of torque
Japans tiny kei cars, unknownin the United States and rarely
seen in Europe, were created in re-sponse to laws that give owners reducedtaxes and insurance costs andbest ofall, in Japans crowded cities, anywayfree parking. To qualify, a car must beno more than 3.4 meters long, 2 metershigh, and 1.48 meters wide, and its enginemay displace no more than 0.66 liters,or 660 cubic centimeters, and produce nomore than 47 kilowatts (63 horsepower).
Daihatsu, Honda, Mazda, Mitsubishi,Subaru, and Suzuki sell kei cars, andmany offer high-performance versionsthat pack nearly as much advanced tech-nology per cc as the gargantuan BugattiVeyron 16.4 (see Endnote). The best ofthe bunch is Subarus R2 Type S, newlyrevised for 2006, because it alone blendsall-wheel drive with a continuously varia-ble transmission (CVT).
a teaspoon under the allowed displace-ment. Unlike some of its kei competitors,it has not three cylinders but four, withfour valves per cylinder controlled by...