Alternative energy sources are clearly still under development. Consequently, whether those technologies are for transportation, heating our homes and buildings, or powering our computers, petroleum-based energy will be with us for a while.

This is particularly true with transportation energy. Amid the national discussion on the future of electric vehicles, biofuels, fuel cells and other advanced technologies, the fact remains that it will take decades before any new engine technology is ubiquitous in the transportation fleet. Consequently, none of the current options has begun to make a dent in U.S. oil consumption in the short term.

So now might be a good time to remember an advanced technology that is often forgotten, the combustion engine, and the promise it still holds for helping the United States meet its short-term objectives regarding oil consumption.

Studies have demonstrated that gains of greater than 45 percent to the thermal efficiency of gasoline engines are achievable in combustion engines, and fuel economy improvements of greater than 50 percent in our automobiles are within our reach when combined with other technical advances. Opportunities abound for combustion scientists and engineers to make even more improvements. The targets can be reached in the near term, not decades from now.

Let me be clear. The United States does need full and long-term commitment to clean, advanced, alternative energy sources for transportation and other needs. Initiatives such as the Energy Department’s Joint BioEnergy Institute (JBEI) in the San Francisco Bay Area are having real impact, and the department is also doing its part to support development of the next generation of biofuels, direct solar fuels, hydrogen fuel cells, batteries and electricity-producing renewables.

But with only modest investments, an existing infrastructure, and a laser-like focus by the nation’s combustion engineers and scientists, we can continue to hone and refine the combustion technologies that have served us so well over the past 100 years.

By Environmental Protection Agency standards, the new Chevrolet Cruze Eco gets 42 miles to the gallon on highways, with some tests even reaching the 50 mpg mark. That’s with a conventional gasoline engine, not a hybrid. With continued investments and research into new technical innovations such as the homogeneous charge compression ignition engine, the potential exists to save more than 4 million barrels of oil per day. That is roughly $400 million per day in savings.

Because transportation represents such a sizable portion of oil use in the United States, we can achieve a 30 percent reduction in overall oil consumption if we can arrive at a 50 percent reduction in fuel use in automobiles and trucks. That is very doable from a scientific standpoint. The engine giant Cummins has already used advanced laser-based experiments to validate models that enabled an all-computational engine design, progress that saved substantial time and cost while providing a better engine and fewer tests. These advances are expanding.

Furthermore, the infrastructure for a fleet of vehicles based on new, advanced technologies is in its infancy and will take years to fully develop. With liquid fuels, we have the infrastructure in place; a complete culture shift around the way we refuel our vehicles would not be necessary.

It won’t be easy for the nation to follow this energy blueprint. Automotive companies are blunt in acknowledging that they can’t solve the technical problems on their own. Their research and development budgets are shrinking, not growing.

Fortunately, the automotive industry is, in an unprecedented way, reaching out to universities and national laboratories to collaborate and build consortia. We already have the core resources, including high-tech tools such as powerful lasers, the fastest computing platforms known to man, and optical engines. All of these resources can and should be leveraged.

Those of us engaged in combustion science see it as our responsibility to bring the various sectors together to find collaborative solutions to our collective challenges, particularly those involving advanced liquid fuels and internal combustion engines. Significant improvements are well within our grasp.

We take the call for research into alternative energy solutions very seriously. But don’t forget the combustion engine. It remains the most proven and the most cost-effective near-term method for reaching the nation’s transportation energy goals.

Robert W. Carling is director of the Transportation Energy Center at Sandia National Laboratories in Livermore, Calif., and oversees the Energy Department’s Combustion Research Facility.