A new review shows that mixing water into diesel fuel can dramatically lower emissions and boost efficiency, offering a surprisingly simple route toward cleaner diesel engines.
A research team at the Federal University of Technology Owerri in Nigeria has drawn attention to a promising method for reducing pollution from diesel engines without lowering engine output.
In their assessment of worldwide studies on Water-in-Diesel Emulsion (WiDE) technology, the group found that incorporating small amounts of water into diesel fuel can sharply decrease harmful emissions while still maintaining, and in some cases improving, overall engine efficiency.
Diesel engines remain central to transportation, agriculture, and many industrial operations because of their strength and reliability. Despite these advantages, they release significant quantities of pollutants such as nitrogen oxides and particulate matter, both of which contribute to smog, respiratory health problems, and environmental warming.
Although emission control systems like catalytic converters and particulate filters can help reduce these pollutants, they also introduce added cost and mechanical complexity. According to the new analysis, WiDE offers a more straightforward and cleaner option that can be used with current diesel engines without the need for redesign.
The WiDE approach involves dispersing extremely small water droplets within diesel fuel with the help of surfactants that keep the blend stable for as long as sixty days. When this mixture burns, the water rapidly turns to vapor, creating a “micro-explosion” that enhances the mixing of air and fuel. This effect lowers the highest temperatures reached during combustion, which limits the formation of nitrogen oxides. At the same time, the improved air–fuel interaction leads to more complete fuel burning, resulting in reduced soot and particulate emissions.
Emissions Reductions and Efficiency Gains
Studies reviewed by the researchers showed that using WiDE can reduce nitrogen oxides by up to sixty-seven percent and particulate matter by as much as sixty-eight percent compared to regular diesel fuel. In addition to cleaner emissions, many experiments also found that engines running on WiDE achieved higher brake thermal efficiency, meaning they converted fuel into useful work more effectively.
“Water-in-diesel emulsions are a practical and cost-effective way to make diesel engines cleaner,” said lead author Dr. Chukwuemeka Fortunatus Nnadozie. “Because the technology does not require redesigning the engine, it offers an immediate path toward lower emissions in developing and developed countries alike.”
The study also examined the role of surfactants, chemicals that allow water and diesel to remain uniformly mixed. The right choice and concentration of surfactant are crucial to maintaining emulsion stability, which affects both performance and safety. Researchers found that formulations using a combination of surfactants achieved the best stability and combustion results.
Future Potential and Research Needs
While WiDE shows great promise, the authors recommend further work to optimize surfactant selection and to study the long-term effects of the emulsions on engine components. They also emphasize that WiDE could complement other clean technologies, such as biodiesel and advanced emission control systems, in achieving global climate and air quality goals.
“This technology can bridge the gap between conventional diesel use and a cleaner energy future,” said co-author Professor Emeka Emmanuel Oguzie. “With proper formulation and testing, it could become an important part of sustainable transportation and industrial power systems.”
Reference: “Advancements in diesel emission reduction strategies: a focus on water-in-diesel emulsion technology” by Chukwuemeka Fortunatus Nnadozie, Chiamaka Prisca Onuoha, Emeka Emmanuel Oguzie and Enos Ihediohamma Emereibeole, 28 May 2025, Carbon Research.
DOI: 10.1007/s44246-025-00210-y
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26 Comments
Wow. 100 year old obsolete tech STILL gets headlines.
Simultaneous combined cycle catalytic staged combustion piston engines require timing and segregation. Mixing water and diesel is kindergarten stuff explored decades ago
Worst idea yet 60 day emersion time. That would be a night mare of unusable stale fuel. Also the alge in diesel loves moisture you just created the perfect enviroment. They have been injecting methanol/ water into the intake for decades to do the exact same thing except without all the mechanical draw backs of in fuel. Oil Institute has a new scam thats gonna kill the engine market. You think its bad now just wait till they try this.
In your scenario yes but all that’s required is to have the water reservoir and mixing device as part of the vehicle. Then the mixing would take place immediately before combustion
Exactly my thoughts when I rad the article. I experienced this 50+ years ago while studying Applied Thermodynamics in college;
And it was “Old Hat” then !!
Steve
Could You Please Explain..In Proper Detail…About Adding Small Amounts..Of Water…In Diesel Fuel??….Are You Stating..”In The Diesel Fuel Tank??”….The Water Seperator Systems Have To Deal With Water…At The Fuel Station Pumps…Are You Referring To ” Water Injection” On The Intake Systems Of The Diesel Engine??…Please Be Specific On This “Wide” Process…
It stated in the article that other stabilizers are needed to keep the water suspended in the fuel up to 90 days to 6 months . So no it isn’t the snow injection and not sure how the water separator will behave with this product but that does give a valid point . Seeing how a water separator is designed to take the water content out of fuel …. Maybe they are eliminating a so called separator ???
We always knew that a diesel engine runs better on a rainy day
The same thing was observed with gasoline engines. I think around the 1950s there were some after-market devices that one could buy to improve both the mileage and performance. They never became standard Detroit components, probably because they depended on water/alcohol reservoirs that had be be kept full. The extra maintenance was probably seen as too much trouble for the average consumer.
The article describes water injection or misting, as well as mixing with fuel; this latter requires pre-mixing with surfactant to disperse the water droplets uniformly and semi-permanently
Next thing you know they’ll tell us is to recycle our exhaust gas… oh wait!
Nigeria.
Sounds like another bs excuse to raise the cost of diesel , even more than it is. Fact that the matter is diesel used to cost a lot less than gasoline now, it costs more and is more harmful if anything.
We need a couple more million to study this…oh… never mind, didn’t work.
Oh look, you learned a new word! Congratulations!
Funny how every good diesel has a water separation filter on it to keep water out of the fuel, cause it ruins the fuel system and destroys the engine, haha
We always knew that a diesel engine runs better on a rainy day
I like how the article states that ‘long term durability testing is required’… ya think?? This will NOT work for areas that see freezing temps, and diesel HP fuel pumps will likely get destroyed with the water as it washes the lubricity from the diesel fuel (not to mention now there is water in there now which will likely lead to rusting)…
Late 60s local shop was injecting water mist in turbo’d diesels….had lots of business back then just as energy crisis in mid 70s came about… then was mostly Ag use, some trucks.
thanks
Yes it’s been known that combustion engines run better in wet weather. Surely though, injecting atomised water into the air intake would be much easier. Fog generators are very cheap these days.
Sorry for repeating. So many things popping up on this page I can’t see what the heck is going on.
Yes it’s been known that combustion engines run better in wet weather. Surely though, injecting atomised water into the air intake would be much easier. Fog generators are very cheap these days.
Oh look, you learned a new word! Congratulations!
This not new. The technology described here was introduced to the market by the French company Total Energies at the end of the last century, beginning in 2000. They set up a dedicated factory for this purpose and sold the emulsion commercially. All this was halted when it became clear that virtually all diesel engines were suffering from injector damage, among other things. Furthermore, there is a risk of increased bacterial growth if the water is not used for extended periods.
The reason is that the water droplets in a water-diesel emulsion made with an emulsifier are too large for the diesel injectors. Reducing the size is not possible because too much emulsifier would be required.
This is an old approach. One probable side effect is erosion of the injector
Snow water/methanol injection kits for gas and diesel engines. They’ve been around for 30+ years! Methanol injection kits have been around since the 50’s LMAO!