Hybrids Get Hot
Forget what you know about gas-electric vehicles: The next generation is built for performance.
The most promising feature of the Honda Dualnote prototype, shown here, is the least apparent: Under its cool-kitsch skin, which looks like a computer-generated CAD drawing come to life, is a hybrid powertrain. In other words, a big electric motor helps this car’s internal combustion engine.
But this is no ordinary hybrid engine. Certainly not like the one in the two-seat Honda Insight, which is just powerful enough to get the 1,800-pound vehicle out of the way of overtaking SUVs; nor the one in the super-lightweight Toyota Prius, which powers the diminutive sedan to 60 mph in a hair under 14 seconds. Great technology, to be sure, but for other people. People willing to sacrifice driving pleasure for fuel economy.
But in the Honda Dualnote, engineers have found the killer app for hybrid technology: high performance. It’s a sea change in how they view hybrids, so much so that some are now calling it “electric turbocharging.” It’s a win-win proposition: You get more power and better fuel economy, while manufacturers can use smaller engines to satisfy performance-minded customers and ever-tightening fuel-efficiency standards. And though Honda has no plans to produce the Dualnote, other automakers have a more immediate date with high-performance hybrids. Detroit is leading the charge: Each of the Big Three plans to put a hybrid truck or sport-utility vehicle in dealerships next year.
The highbred hybrid’s roots date to 1998, when Don Panoz’s Le Mans racing team discovered that shoehorning a 195-horsepower electric motor and a 300-volt nickel-metal-hydride battery alongside the gasoline engine would give the team’s car an edge. It successfully competed in a race, but the team didn’t have enough time or money to develop the car as its primary racer. Several Formula One teams, though, got wind of the idea and started pursuing hybrids of their own.
Their plan was to use a car’s alternator-the mini generator in every vehicle that keeps the battery charged-as an electric-assist motor that could contribute small boosts of power. This prompted the Formula One sanctioning body to ban the technology before it ever got to the track. “They had to,” says John Wallace of Ford’s electric-centric Think division. “Teams without it would have had their behinds waxed.”
Not because these cars would be so much faster, just quicker off the line. In fact, electric turbocharging doesn’t increase top speed at all, but significantly shaves 0-to-60 times-a more useful and apparent measure of speed for most drivers. This is because electric motors make maximum power at low speeds but lack oomph at the higher end. Add all-wheel drive, as the Dualnote concept does, and acceleration is even better because power is going to all four wheels. “With the extra torque,” says Hans Glonner, head of hybrid research at BMW, “we can make a 3.0-liter engine feel just like a 6.0-liter engine, without losing any efficiency.”
This size-output disparity is most evident in the Dualnote, the poster child for this new generation of hybrids. Unveiled late last year, the Dualnote has an impressive 400 horsepower under the hood, but only 300 come from its 3.5-liter V6 engine. The rest is thanks to three electric motors: a large one-Honda calls it an “integrated motor assist”-near the mid-mounted engine and two small ones at the front wheels. You’d expect this sports coupe to guzzle gas, but it doesn’t. In fact, at 42 miles per gallon, it’d be one of the most fuel-efficient cars on the road today, in the same range as the beer-can-sized Chevrolet Metro and Toyota Echo.
Instead of a conventional battery pack, as in the Prius and Insight, the Dualnote features a king-size ultracapacitor-that is, a high-performance energy-storage device. “Ultracapacitors charge and discharge more rapidly than batteries,” explains Ben Knight, vice president of technology at Honda. “That not only gives you a more responsive feel, but also much quicker acceleration.” Other high-performance hybrid designs do call for batteries.
When the Dualnote stops, its sophisticated computer control system switches off the gas engine. Hit the accelerator pedal, and the three electric motors kick in first. Both the motors and engine bring the vehicle up to speed, with the former drawing energy from the ultracapacitor and then delivering power to all four wheels. A computer decides how much power goes where, depending on the individual traction of each wheel. All of this happens nearly instantaneously. “This is what people hoped to get with turbocharging, but didn’t because of turbo lag,” says Wallace, referring to the delay that occurs when an engine’s turbocharger builds boost pressure to increase power.
The two electric motors at the front wheels contribute to acceleration, but their main benefit comes during deceleration. Here, the motors spin in reverse, recharging the ultracapacitor-it’s a similar setup to the regenerative braking systems found on the Insight and Prius. The electric motors even recapture energy while turning: Because the inside, faster-moving wheel doesn’t need as much torque as the outside wheel, the saved mechanical energy is converted to electrical energy and used to recharge the ultracapacitor.
The Dualnote’s high-tech internal combustion engine also helps. It’s an all-aluminum double overhead cam V6 that incorporates Honda’s i-Vtec valve-control technology. An internal computer varies valve lift to adjust the amount of fuel entering the cylinders based on engine speed, and it also constantly fine-tunes the camshaft timing to make tremendous power while conserving fuel.
Of course, as a concept, one component to the Dualnote is missing: a price tag. So while bells and whistles (that is, three electric motors) are fine for a one-of-a-kind sports car, real-world high-performance hybrids will be much more humble.
The initial focus will be on gas-guzzling pickup trucks and sport-utility vehicles, where automakers can use smaller, more fuel-efficient engines without compromising power. Ford, for example, is planning a hybrid version of its compact Escape SUV for the 2004 model year. With an electric motor, the 2.0-liter four-cylinder 127-horsepower hybrid Escape will match the acceleration of the 3.0-liter 201-hp V6 version currently available-and deliver 40 miles per gallon. “We’re breaking the link between fuel economy and performance,” Wallace says, adding that though a hybrid drivetrain will add about $3,000 to a new vehicle’s cost, this premium will likely be offset with a federal tax credit.
DaimlerChrysler, meanwhile, is developing a V6-powered hybrid of its midsize Durango sport-utility, also for 2004. Most buyers choose a V8 engine, but Dodge says the smaller powerplant-with some help from an electric motor-can outrun the V8 with less to drink. The company also plans a hybrid-electric Jeep Liberty for 2004 that will have a four-cylinder engine but will out-accelerate the current V6 version. Even Honda is considering small SUV hybrids. Acura, its luxury division, recently unveiled the concept RD-X, which squeezes 250 horsepower out of a modest 2.4-liter four-cylinder engine. There are no production plans yet.
Though hybrid technology seems ideal for small and midsize trucks, it gets a little thorny with heavy-duty pickups. According to engineers at General Motors, V6-powered hybrids may be able to out-accelerate V8s, but they can’t out-haul them. That’s because an electric motor would quickly drain its battery when carrying a heavy load, leaving the V6 to shoulder the burden alone. “We plan to offer a hybrid feature to improve fuel economy, as long as it doesn’t degrade performance,” explains Richard Marsh, GM’s program executive for hybrid trucks. “People buy trucks to use them as trucks,” he adds. “There’s not a lot of interest in trucks with small engines.”
Dodge faces the same issue with its hybrid-electric full-size Ram pickup. Engineers there have decided to stick with a V8, supplementing it with an electric motor only for acceleration. The result: more power from a stop, the same towing capacity, and better gas mileage. Like GM with its full-size GMC Sierra and Chevy Silverado, Dodge hopes to put the hybrid Ram in dealerships next year.
If all goes well with these initial vehicles, expect to see more-especially as the industry begins the transition from 12- to 42-volt electrical systems in 2004. Key to 42-volt systems is what’s called an “integrated starter-alternator”-basically the alternator is built into the engine’s flywheel instead of being driven by the fan belt, a design that can deliver 10 times more electrical power than today’s vehicles. Add a storage device, such as an ultracapacitor or battery, and you have a hybrid vehicle.
Such a high-power delivery system will make all kinds of hybrid configurations feasible, not only for the Dualnote but for existing sports cars such as the Chevrolet Corvette and Dodge Viper. The hybrid configuration Dodge is using in the Durango and Ram is similar to the Dualnote’s-an electric motor powers the front wheels, a gas engine the rear wheels. A Viper with this setup would get 10 percent better gas mileage and 20 percent more torque, says Larry Oswald, DaimlerChrysler’s vice president of hybrid engineering. “That would take another second or two off its 0-to-60 time,” he says. In other words, it’d get to 60 mph in less than 3 seconds.
Which proves an old adage wrong, or at least adds an asterisk to it: There is in fact a “replacement for displacement”-and it’s coming to a showroom near you.