Heavy-duty semi trucks might be the lifeblood of the supply chain, but they’re not exactly good for the environment. Nearly all are fueled by diesel engines, emitting ground-level ozone that damages trees and crops and produces acid rain. Many currently in operation in the U.S. predate regulatory changes enacted 30 years ago that mandated the production of cleaner motors. The older, dirtier ones have an ever bigger negative environmental impact.
One way to address the problem is to replace diesel-powered trucks with battery-powered electric vehicles (EVs). That’s a high priority for the U.S. government, but it’s still a long way off. For now, the most practical solution is to make existing internal combustion engines more eco-friendly.
That’s the focus at ClearFlame Engine Technologies, an Illinois startup that modifies diesel motors so they run on low-carbon fuels such as ethanol and methanol.
The company uses an innovative technology called high-temperature mixing controlled compression ignition (MCCI). It enables ethanol and methanol to behave like diesel fuel — only with lower emissions and costs.
One of ClearFlame’s biggest selling points is that its modifications have little impact on performance. The company claims that the modified engines get the same torque as the diesel versions without using fossil fuels.
“Our innovation is low-cost for engine manufacturers to implement and integrate into existing production processes,” ClearFlame states. “We can even help to remove the pollution from the millions of diesel engines already in service through remanufacturing or retrofitting using our flexible technology. And, our engines can run on many low and zero-carbon fuels, offering benefits to a wide range of countries around the world.”
Getting diesel engines to run on ethanol and methanol is no simple feat, considering that low-carbon fuels tend to ignite at higher temperatures. Among ClearFlame’s solutions was to remove many of the traditional cooling components in a typical compression-ignition engine so it would be hot enough to ignite low-carbon fuels.
ClearFlame’s technology development has been supported by multiple industry manufacturers and government agencies such as the U.S. Department of Energy, the Department of Agriculture, and the National Science Foundation. The company also has attracted the interest of high-profile investors.
In October 2021, the company raised a $17 million Series A funding round led by the Bill Gates-founded Breakthrough Energy Ventures.
Other investors included construction equipment giant John Deere. Less than a year later, ClearFlame signed agreements with truck refitting companies to add its technology to existing diesel vehicles. The startup also rolled out its first pilot fleet trial with a ClearFlame truck running on ethanol.
ClearFlame was co-founded in 2016 by Julie Blumreiter and B.J. Johnson, who met as mechanical engineering Ph.D. students in Stanford University’s Advanced Energy Systems Laboratory. Today, Blumreiter serves as Chief Technology Officer, and Johnson serves as CEO.
The company’s focus on modifying traditional internal combustion engines to run on ethanol has not won much support from environmental groups that favor trucks powered by batteries or renewable energy sources. But ClearFlame defends its technology as a way to provide a low-carbon alternative to fossil fuels in an industry that is in dire need of decarbonizing.
“To meet the emissions reduction goals of the Paris Climate Accord — as well as meet California, New York, and other state commitments to reduce greenhouse gas emissions by 80% by 2050 — we need to achieve significant carbon reductions in the next decade,” Johnson said.
