Lighting the Fires of Carbon-Free Combustion

When he arrived at Stony Brook University in 2020, Dimitris Assanis was revved up.

After earning his bachelor’s degree, master’s degree and PhD (all in mechanical engineering) at the University of Michigan, Dr. Assanis completed multiple postdoctoral assignments – a UMich fellowship researching dual pre-chamber engines, a University of Delaware gig exploring novel energy-efficiency technologies for automated vehicles.

Then he joined Assanis & Associates Inc., a Detroit-based consultancy focused on automotive advances, serving as principal engineer.

But when Stony Brook University came into play – specifically, SBU’s Advanced Energy Research and Technology Center (AERTC) – Dr. Assanis quickly and excitedly shifted gears.

As an assistant professor in Stony Brook’s Department of Mechanical Engineering, he took the baton from Associate Professor Sotirios Mamalis and Assistant Professor Benjamin Lawler, who’d both left the university after years of promising research into newer, better internal-combustion engine (ICE) technologies.

Sliding into the ICE laboratory checked off several boxes for Dr. Assanis, who bristles at any suggestion that internal-combustion technologies are dead and was “personally looking for a Big 10 engineering program” to support his research.

“It was a dream to come and work at Stony Brook University,” he notes. “And that dream became a reality.”

This reality would allow the hands-on researcher to combine multiple familiar disciplines. While he “started out as an experimentalist,” somewhere in the latter stages of his graduate career, Dr, Assanis incorporated applied computational mathematics – and “now I’ve merged the two worlds back together.”

His work starts with this simple baby-and-the-bathwater premise: Essentially, it’s not the internal-combustion engine’s fault.

“An internal-combustion engine is a thermodynamic-conversion device that’s only bad because we decided to put fossil fuels in it,” Dr. Assanis says. “This engine has been around for many, many decades, over a century and a half – how bad a job have we done to bring it to this point?

“We basically stopped innovating,” he adds. “It’s not the engine’s fault.”

Carbon dioxide, of course, is a side effect of combusting carbon-based fossil fuels. So the idea, according to Dr., Assanis, is to run the basic technology on alternative fuels with low- or zero-carbon emissions, and he references several potential fuels for “carbon-free combustion.”

There’s this one experimental biofuel – made from the woody biomass of a Douglas fir – that’s shown to mix well with diesel, dramatically reducing diesel’s carbon emissions and significantly improving its cold-weather performance.

And then there’s carbon-free hydrogen, which mixes well with several other carbonless combustibles – though burning hydrogen can result in nitrogen oxides, a gaseous air pollutant.

That’s where Dr. Assanis and his team come in, tailoring “advanced combustion strategies” to avoid NO_x emissions in the combustion chamber. The laboratory is knee-deep in hydrogen blends – hydrogen combined with methane, natural gas, ammonia, even carbon monoxide, all to formulate the right combination of environmentally sensitive combustibility.

Unfortunately for the researchers, the action largely takes place inside what Dr. Assanis calls “black boxes” – shielded combustion chambers, where gathering data can be challenging.

This calls into play the assistant professor’s computational-mathematics experience. Through a collaboration with SBU’s Institute for Advanced Computational Science, Dr. Assanis and his group digitally recreate the environment inside those black boxes, affording an otherwise-impossible glimpse of potential alternative-fuel breakthroughs. 

“This helps us understand what’s going on inside the chamber when we observe interesting performance,” Dr. Assanis says. “We can see inside, basically, using our computational skills, which guides our experimental research.”

And that’s just one example of the AERTC’s fantastic in-house resources and smart outside connections. Right up there with the Advanced Energy Center’s next-generation equipment and laboratory facilities, the scientist relishes the opportunity to compare thinks with likeminded scientists working throughout the building.

“I get to interact with all those outstanding companies and personnel,” Dr. Assanis says. “There really is a very nice atmosphere at the AERTC – everyone is on the cutting edge, and it forces us to remain on the bleeding edge, which I like.

“We’re often requesting support letters from David Hamilton’s operation and willing to help other companies that are working to advance and demonstrate their technologies” Dr. Assanis adds. “I’m always excited to say ‘yes’ and help an incubator company when I can.”

The innovator also notes associations with Brookhaven National Laboratory and SBU’s Institute of Gas Innovation and Technology. Such high-caliber partnerships, he says, will ultimately lead to zero-carbon power systems for large-scale shipping operations, and possibly zero-emission electric-power stations. 

“You can absolutely make hydrogen engines (for cars), but perhaps this application is better suited for planes, trains and ships, or distributed power generation,” Dr. Assanis says. “Working [at the AERTC], we have the best chance to develop the technology and determine its best uses.

“And we’re housed in the same building with all these other energy companies,” he adds. “We can just go down the hallway and bounce an idea off an expert, maybe an expert outside our topical expertise, and get an answer immediately.

“How terrific is that?”