Hybrids to the Rescue

They've been making major gains and could soon make their mark

This is part of IEEE Spectrum's special report: What's Wrong—What's Next: 2003 Technology Forecast & Review.


Tech Watch

The starter motor-generator in TOYOTA'S CROWN MILD HYBRID improves fuel economy and lowers emissions

42-V AUTOMOTIVE ELECTRICAL SYSTEMS, the coming standard for cars, are critical to the operation of mild hybrid vehicles

The proprietary POLYMER ELECTROLYTE FUEL-CELL STACK that powers Toyota's fuel-cell hybrid car holds enough compressed hydrogen to run its 80-kW motor for 290 km between refuelings


We've been told that electric cars would cure our passionate yet troubled relationship with the automobile. With their superior efficiency and cleaner emissions, we could keep the good things, freedom and mobility, and limit the bad, pollutants and oil dependency.

For six years now, electric vehicles have been available in a variety of configurations and styles. But like an earnest yet boring suitor, they've been mostly spurned.

The courtship began in 1996, when General Motors Corp. (GM) leased its first electric vehicle (EV-1) to drivers in Arizona and California. Disappointingly few went out on the road: for example, in 1999, GM leased just 137 EV-1s.

The company pulled the plug on the car early last year. Though expected, it was a ringing blow to the EV industry after a series of jabs, including the discontinuance of the Ford Ranger EV, and the Nissan Altra EV. Also last year, Ford Motor Co. put its Th!nk Mobility subsidiary up for sale. Ford had bought Th!nk, maker of a two-seat plastic-bodied electric hatchback, in 1999, and had pumped US $100 million into it.

Though so-called pure EVs were battered in 2002, the year was fateful in more ways than one. The good news is that hybrid EVs (HEVs) picked up the slack from the declining pure EVs. Hybrid sales were surprisingly strong, carving out what seems to be a growing niche in the United States, Europe, and Asia.

What went wrong with EVs?

The differences between pure and hybrid EVs go a long way to explaining their crisscrossing trajectories. Consider the EV-1: it perished amid a storm of finger-pointing and conspiracy theories, clouding the issue of why it failed. It was widely rumored that GM lost money on each EV-1 produced, and proponents of the car insist GM took to subverting its own product to minimize its losses, discouraging people who were interested in it. GM denies the accusation, and says it was merely a matter of supply and demand: too little of the latter to justify the former.

Regardless of the contretemps, it is clear that EVs suffer from limitations that were simply unacceptable to the average motorist. Their worst deficiency is range: EVs on the road today can go only about 80 km between charges. A full recharge takes at least several hours. And the batteries, usually bigger versions of the lead-acid type found in all cars, perform poorly in cold weather, and have none too long a life. Owners have to replace the batteries periodically, at a cost of $10 000 or more.

Hybrid-electric vehicles get around these problems. In their most popular configuration, the small gas engine helps propel the vehicle only at cruising speeds above, say, 30 km/h, and only operates in the narrow rpm range over which it delivers maximum torque and is most efficient. On long trips, the gas engine recharges the car's battery pack as needed, using the electric motor as a generator. Recharging on the fly extends a hybrid's range to that of a conventional car. At higher speeds or on hills, the motor assists the engine, pitching in extra power.


Wish List

MORE STRINGENT FEDERAL FUEL ECONOMY RULES would force carmakers to put hybrid electric powertrains in otherwise gas-guzzling sport-utility vehicles

Higher gasoline prices would make FUEL ECONOMY a bigger issue for U.S. car buyers and makers

TAX INCENTIVES that would benefit buyers of cars that meet stringent fuel economy and emission standards


There are other advantages. Operating the engine consistently in its "sweet spot" improves its fuel economy and drastically cuts emissions. Another plus is regenerative braking, in which the motor/generator converts the energy used to slow or halt the car into electricity, which in turn charges the battery, rather than wasting it as heat.

The first hybrid from a major manufacturer was the Toyota Motor Co.'s Prius, introduced in Japan in 1997. It has a fuel economy of 4.5 liters per 100 kilometers (52 miles per gallon). Toyota began producing the Prius in a conservative run of 2000 units, and was surprised when demand for the vehicle easily outstripped its availability. By 2002, annual sales of the Prius reached 12 000 cars worldwide. The company expects to sell 17 000 in 2003, a spokesman said.

Overall, by this past August, Toyota had sold more than 100 000 hybrids worldwide, including the Crown luxury sedan and Estima minivan sold only in Japan. Though still a minuscule portion of the global car market—nearly 17 million vehicles are likely to be sold or leased in the United States this year alone—Toyota's figures dwarf those of pure EVs.

The other hybrid that has been around for several years is Honda Motor Co.'s Insight, a cozy two-seater. It has the best fuel economy of all: 3.5 L/100 km, or 68 mpg. Honda has also added a hybrid version of the company's four-passenger Civic, which became available in the United States for the first time last year.

Regular or mild

The world of hybrids became bigger and more interesting in August 2001, when Toyota introduced a so-called mild hybrid version of the Crown luxury sedan. Others, such as GM and DaimlerChrysler AG, are following suit, debuting mild-hybrid versions of pickups such as the GMC Sierra and Dodge Ram in 2004.

Mild hybrids offer slightly better fuel economy than conventional autos (on the order of 5-15 percent), but cost much less to produce than regular hybrids. Although regular hybrids can improve fuel economy by up to 400 percent, that advantage comes at a cost: with its dual power plants, Toyota's Prius is said to cost far more to make than its $19 995 sticker price. (A Toyota spokesman declined to comment on the Prius's production cost or to say whether the carmaker is turning a profit on the vehicle.)

A mild hybrid makes do with a beefed-up starter-generator and a 42-V electrical system. The starter-generator cannot actually move the car, but it can assist propulsion and recover energy through regenerative braking. For example, it allows the vehicle's engine to be shut off when the car is stopped at a traffic light, and provides an initial burst of propulsion when the driver depresses the accelerator pedal. Shutting off the engine when the car is not moving saves fuel and cuts down on emissions.

It's the taxes!

For clues to making hybrids more attractive to car buyers, look to Japan, where the price of gasoline is four times higher than in the United States. In addition, taxes are assessed based on the weight of the vehicle, and tax breaks, including a 2.7 percent reduction on the sales tax if the car qualifies as a low-emissions vehicle, are offered. If it is a hybrid, an additional 2.2 percent is knocked off this tax.

Granted, there has been incremental adoption of tax incentives in the United States, such as a one-time, $2000 federal tax deduction for hybrid car buyers, plus state incentives like New York's recently announced $2000 tax credit, and various incentives offered by regional agencies in California. But the government has mainly focused its attention on—and loosened its purse strings for—pure EVs. A $4000 federal tax credit on EVs, for instance, does not apply to hybrids.

The failure of EVs proves that fuel efficiency is not enough to woo consumers when fuel prices are low, and that we won't ever part with the amenities and performance that have fed our continuing love affair with conventional cars. But as many automakers make plans to introduce 42-V electrical systems on many of their models, mild hybrids, followed by full hybrids, will be a logical evolution. A study by the Freedonia Group (Cleveland, Ohio), a market research firm, predicts that once other carmakers begin ramping up HEV production, there could be as many as three million hybrids of all types on the world's roads by 2010. Hybrids could have a good shot at satisfying our intellects as well as our passions.

To Probe Further

For an excellent explanation of how mild hybrid electric vehicles work, see http://www.sae.org/42volt/toyota.pdf

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