ExxonMobil’s diesel formulation saves fuel and cuts emissions

ExxonMobil fuel pump with engineer Lilo Hurtado

Two years after it went on sale in small test markets in Michigan and Texas, ExxonMobil (NYSE: XOM) and its Synergy Diesel Efficient now adorn fuel canopies at 7,500 independent truck stops and 425 commercial fuel depots.

The 20% drop in diesel fuel prices could get more truckers to check out the diesel formulation’s benefits: 

  • At least 2% or better fuel efficiency.
  • Lower oxides of nitrites (NOx) emissions
  • Elimination of fuel additives
  • Cleaner fuel system operation

When diesel prices were soaring, some fleet managers saw less-expensive natural gas as a way to preserve their fuel budgets. But the cost of maintaining a natural gas engine is up to four times higher than a diesel engine.

The opposite is true with Synergy Diesel Efficient. The fuel costs more but maintenance benefits even out, or improve, total cost of ownership.

“We saw that the dynamics of how the fuel system operates and the role that it’s going to play was going to be more and more critical,” ExxonMobil applications engineer Lilo Hurtado told FreightWaves at the NATSO annual conference in February. “We wanted to stay ahead of the market to try and anticipate that and came up with the new fuel.”

While the name Synergy Diesel Efficient may not roll off the tongue, it is an attempt to brand diesel fuel the way lubricants like Shell Rotella or Mobil 1 go to market. 

“When you go from one [fuel] supplier to another, it’s perceived that all you are doing is swapping out the BTU [British Thermal Unit] molecules,” Hurtado said. “We’re offering not just the fuel but also branding commercial sites. Vehicle operators like the fuel and they’re coming back. There’s a lot of word of the mouth in the trucking industry.”

Under pressure

Fuel, once injected into an engine at a pressure of 5,000 pounds per square inch (PSI), is now injected at closer to 40,000 PSI.  

The eight-times-greater pressure matters because higher heat and stress placed on the fuel injector results in burning more fuel and releasing higher emissions.

In third-party testing, Hurtado said Synergy Diesel Efficient showed a 2% improvement in fuel economy in trucks used every day to make money. The fuel economy improvement meant a similar reduction in CO2 emissions. An unexpected bonus: an 11% reduction in NOx emissions.

Downstream benefits include fewer regenerations of the diesel particulate filter, which must be  periodically flushed. That results in the need for less diesel exhaust fluid (DEF). 

“We’re making an effort to do something more with the fuel and also be more friendly to the aftertreatment system,” Hurtado said,

California dreaming

Efforts to make diesel engines and diesel fuel more efficient largely fall flat in California, which is seeking to get diesel trucks off its roads by 2035. The state is tightening the screws on diesel emissions and promoting the zero tailpipe emissions of battery electric vehicles.

But California’s goal faces the reality that 1 billion more people will populate the planet by 2040,  doubling global economic output by some estimates. That means more trucks will be needed to haul more stuff. ExxonMobil doubts hybrids and electrics will be sufficient to meet the demand. 

“When I talk to the industry, [diesel] is going to be the one that’s going to be the path forward,” Hurtado said.

California wants alternatives to smog-belching diesel because of “our incredibly poor air quality,” Barbara Riordan, a member of the California Air Resources Board (CARB), told FreightWaves. “In the past, hybrids have been considered a transition, so maybe a hybrid might be considered. [Diesel] is certainly going to be used far less than it ever has before.”

No more self medicating

Diesel mechanics and owner-operators use additives to improve engine performance.

“Our approach is ‘Why make the truck driver a chemist?’” Hurtado said. “We’re offering a fully formulated fuel directly from our terminals. You don’t have to self-medicate so to speak.”

Synergy Diesel Efficient is blended with several concentrations of biodiesel, which uses animal fat and vegetable oils to reduce emissions. But biodiesel does not burn as completely as regular diesel, generating greater particulate matter. The ExxonMobil product helps cut down on the buildup of soot on fuel filters, Hurtado said.

Matt Van Zanten, general manager of J.&H Oil Co. in Wyoming, Michigan, tested Synergy Diesel Efficient with regional carrier Holland Special Delivery. It used the ExxonMobil product in some trucks and standard diesel in others. Synergy Diesel Efficient provided up to 4% better fuel economy.

During the Polar Vortex in January 2019, Van Zanten debated whether to use a cold flow additive. He called Hurtado, who said to let Synergy Diesel Efficient work alone. One J&H customer ignored the advice. The company’s truck engines failed in the minus-25 degree temperatures. Two other customers reported no issues.

“This is an additized diesel fuel that is a completely different product,” Van Zanten told FreightWaves. “It’s given us an edge over our competitors. We’re out of the additive business.”

The price of a gallon of diesel fuel has been sliding amid a glut of crude oil. (Chart: DTS.USA/SONAR/FreightWaves)