For all the talk of electric cars, the old-fashioned internal combustion engine is proving to be hard to beat

By  Steve LeVine  wsj.com   Jan. 30, 2015 2:27 p.m. ET

When most of us picture the high-tech personal mobility of the future, we tend to imagine a sleek, dead-quiet electric car, packed with voice- or motion-directed gizmos and self-driving features. We see ourselves gliding around almost effortlessly, free to talk, work or text as we see fit.

What few of us conjure up is having this sort of experience in a gasoline-fueled car. But that may be changing in the face of recent design advances. The internal combustion engine—the workhorse of the industrial age—is proving to be much more than a stubborn technological incumbent.

More than a century after becoming the dominant way that people move around, gas-powered cars are challenging ostensibly more advanced electric vehicles. It has proved hard to beat engines in which fuel is ignited, drives pistons and propels a vehicle. Even in 2040, according to forecasting agencies such as the U.S. Energy Information Administration, cars with gas- and diesel-powered engines will still represent some 95% of the international car market.

One reason is that refinements of combustion-engine technology are mandated: U.S. government standards require cars to average 54.5 miles a gallon by 2025, up from 25.1 mpg last year. To get there, car makers are improving efficiency with direct fuel injection (which allows gasoline to burn more efficiently), aluminum bodies and smaller engines. Scientists are making progress on a super-battery that may some day push aside combustion, but they’re a long way from making electric cars competitive in the mass market.

Last year, 16.5 million light vehicles were sold in the U.S. The top three were combustion pickups—the Ford F series, the Chevy Silverado and the Dodge Ram, which together account for 1.7 million vehicles. Just 119,710 pure electrics and plug-in hybrids were sold, 0.7% of the total (excluding final quarter sales of the Tesla S, whose numbers will come out in February). Most market observers don’t expect these proportions to shift much over the next two decades.

This view may be too complacent. At a time of technological and political upheaval, with big changes in the energy sector too, research on batteries and electric cars may yet leap ahead. Nor does combustion technology look so advanced at the moment.

Today’s mass-market diesels probably have the world’s most efficient combustion engines: As much as 45% of the fuel ends up being used to propel the vehicle. But 55% of it still just burns off as wasted heat. Gasoline is worse. Just 18% of its energy actually reaches the wheels; a whopping 82% goes into the ether. Even today’s best combustion engines aren’t so terrific at turning fuel into motion.

Still, for now at least, they continue to advance, maintaining gasoline’s lead. At a place like the federally-funded Argonne National Laboratory in Lemont, Ill., one of the country’s leading research centers on batteries and automobiles, refinements of old combustion technology still attract the attention of industry experts.

At the laboratory’s advanced combustion unit, engineers tear apart and appraise almost every major automobile manufactured on the planet. They believe that engines powered by fossil fuels can easily achieve 35% or even 40% better mileage in the next few decades.

An engine that has attracted particular attention is the Achates, a unique, diesel-fueled technology. It features opposed pistons, which face each other in a single cylinder rather than sitting side by side as in a conventional engine block. Achates Power, the engine’s San Diego-based developer, says that it gets 30% better mileage per gallon than current diesel engines—and double the mileage of gasoline engines.

“The Achates doesn’t need any weird sealing, no super materials that don’t exist, and it has no manufacturing issues with ceramics or geometry or anything unusual,” says Don Hillebrand, who heads the advanced combustion unit at Argonne. Such demands typically cripple vehicle innovation, whether combustion or electric.

Most industry experts argue that advances in combustion alone will carry the U.S. vehicle fleet to an average of at least 40 miles a gallon, a big part of the way toward the mandate of 54.5-m.p.g. by 2025. Electrics, along with cars propelled by fuel cells and natural gas, will get the fleet average—the standard used by the government—the rest of the way.

In short, even if motorists maintain their long-standing attachment to the combustion engine in the years ahead, the world may burn 20 million fewer barrels of oil a day—a big chunk of fuel considering that today our overall consumption of oil, for all purposes, is only about 90 million barrels a day. Just as the skyrocketing production of shale oil has shaken the economies and politics of Russia and OPEC in recent months, the global surplus from advances in combustion technology will keep down oil and gasoline prices everywhere.

“Taking the infrastructure we have, using engines we understand with no new costs—that is where we are going in the next 15 years and what is going to compete really effectively with electrics,” Mr. Hillebrand said.

The real challenge is for electric cars to figure out a way to compete head-to-head with combustion. Walking into a showroom, a potential buyer needs to be certain that an electric’s cost advantage in terms of fuel consumption will pay off enough over three or four years to justify the higher sticker price for the car itself.

GM and Tesla are taking the first move in that direction with plans for rival 2017 or 2018 vehicles with price tags of about $30,000 (after government subsidies) and a range of 200 miles without recharging. These terms will make electric cars directly competitive with comparable combustion-powered cars for the first time. Tesla, for instance, is positioning its Model 3 to challenge the BMW Series 3, the German car maker’s $35,000 entry-level offering.

Some in the industry doubt that Tesla can retain its styling prowess at that price. Nor will the Tesla or GM models be cheap enough to truly penetrate the mass market: Combustion-powered cars won’t feel real market pressure until credible electrics are available in the mid-$20,000 range. Still, the plunge of a few car makers into the low-end of the luxury market is a watershed for electrics.

The day may yet come when electric cars are the exciting future of personal transportation for the average consumer. For now, however, the road still belongs to combustion.