Sandia researcher John Dec holds a specialized optical piston used in engine research at the Combustion Research Facility. | Photo courtesy of Randy Wong, Sandia National Laboratories.
More than 10 million heavy-duty vehicles drive on U.S. roads each day, hauling goods, transporting people, and performing essential tasks like utility repair. However, these vehicles would be very different today if it wasn’t for the work of the Energy Department’s Vehicle Technologies Office (VTO). Decades of research has led to combustion engines in heavy-duty vehicles being more efficient and cleaner than they would have been otherwise.
In fact, the 2010 study “Retrospective Benefit-Cost Evaluation of U.S. DOE Vehicle Combustion Engine R&D Investments” examined the benefits of combustion research done at Sandia National Laboratories' Combustion Research Facility (CRF), which is co-funded by VTO and the Energy Department’s Office of Science. It found that this research resulted in more than $70.2 billion in savings (or $23.1 billion adjusted for net present value) in fuel and health costs.
Research at Sandia’s CRF focuses on: 1) laser diagnostic and optical engine technologies and 2) combustion modeling. Laser diagnostic and optical engine technologies allow researchers to:
- Measure the speed and direction of fluids (such as fuel droplets)
- Better understand the spatial distribution of fuel droplets
- Observe collections of molecules common in combustion
- Determine properties of soot
- Collect other essential data for improving scientific understanding of the combustion process.
Combustion modeling allows researchers to use computers to conduct “experiments” much faster than they would be able to in the laboratory.
Based on expert interviews about the research conducted from 1986 to 2007, the study concluded that without the CRF, fuel efficiency in heavy-duty diesel engines would have been 4.5% lower than the actual efficiency was in real life. These improvements resulted in 17.6 billion fewer gallons of diesel fuel used than would have been otherwise. This is the same as $34.5 billion in fuel costs saved alone!
These fuel savings also led to 177.3 million fewer metric tons of CO2 emissions, the same as removing one-third of all light-duty cars from the road for an entire year.
These efficiency increases also reduced emissions of criteria pollutants that contribute to poor air quality and can exacerbate respiratory and cardiovascular diseases. The research enabled heavy-duty engine manufacturers to meet the Environmental Protection Agency’s strict 2007 regulations, which required a 90 percent reduction in particulate matter (PM) emissions and a more than 50 percent reduction in nitrogen oxide (NOx) emissions. The avoided emissions resulted in another $37.5 billion in health benefits.
On top of these quantitative measurements, this research established a foundation for more than a dozen important technologies, such as fuel injection, low-emissions diesel fuel, and exhaust gas recirculation. Many of these technologies are used today in combustion engines, while others may be in the future. For instance, some have been used in the demonstration Class 8 trucks developed under VTO’s SuperTruck project, which has the goal to develop tractor-trailers that are 50% more efficient than baseline models. As fuel economy regulations set by the Environmental Protection Agency and Department of Transportation become more stringent, manufacturers may turn to these technologies to improve efficiency.
Working with the CRF and other research stakeholders, VTO continues to push combustion engine efficiency forward in both light and heavy-duty vehicles. If VTO is successful in meeting its technical goals and these technologies are widely adopted, it would reduce highway petroleum use up to 1.8 million barrels a day by 2020. With the potential to save consumers and businesses trillions more dollars, combustion research has an admirable past and bright future.