The automotive world is once again buzzing about a technology that could rewrite the rules of the internal combustion engine — and this time, it isn't a hybrid or a fuel cell. Mazda has filed a patent for a six-stroke engine that extracts hydrogen from ordinary gasoline, burns the hydrogen for propulsion, and captures the carbon before it ever reaches the tailpipe. If it works as described, drivers could fill up at any gas station and still drive away with near-zero CO2 emissions. It's a bold idea, and it deserves a close look.
The patent addresses real frustrations that continue to dog electric vehicles: long charging times, range anxiety, towing limitations, and a charging infrastructure that still hasn't caught up with demand. EVs remain a genuine zero-emission solution, but they aren't the only path forward. Mazda's approach asks a different question — what if a gasoline-burning engine simply stopped releasing carbon dioxide? That would be a remarkable answer to one of the industry's hardest problems.
Mazda Created A New Hydrogen Engine That Uses Gasoline
So far, the new Mazda six-stroke engine is nothing more than a filed patent with the US Patent and Trademark Office, but the idea is intriguing. The patent is called "fuel reforming system for vehicle," which doesn't do the engine justice, especially considering what it could mean to the industry. In a nutshell, this engine is built to make hydrogen from gasoline, using heat and a catalyst built within the engine's systems.
This new engine is designed to recover carbon, improve thermal efficiency, and result in a vehicle that runs carbon-neutral. It shouldn't be too surprising that Mazda came up with such an idea — the brand has been at the forefront of unconventional engine technology for decades, from the rotary Wanky engine to its proprietary SKYACTIV-X compression-ignition gasoline technology.
The automotive world is once again buzzing about a technology that could rewrite the rules of the internal combustion engine — and this time, it isn't a hybrid or a fuel cell. Mazda has filed a patent for a six-stroke engine that extracts hydrogen from ordinary gasoline, burns the hydrogen for propulsion, and captures the carbon before it ever reaches the tailpipe. If it works as described, drivers could fill up at any gas station and still drive away with near-zero CO2 emissions. It's a bold idea, and it deserves a close look.
The patent addresses real frustrations that continue to dog electric vehicles: long charging times, range anxiety, towing limitations, and a charging infrastructure that still hasn't caught up with demand. EVs remain a genuine zero-emission solution, but they aren't the only path forward. Mazda's approach asks a different question — what if a gasoline-burning engine simply stopped releasing carbon dioxide? That would be a remarkable answer to one of the industry's hardest problems.
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Mazda Created A New Hydrogen Engine That Uses Gasoline
Mazda CX-5 Engine
Mazda CX-5 Engine
Via: Mazda
So far, the new Mazda six-stroke engine is nothing more than a filed patent with the US Patent and Trademark Office, but the idea is intriguing. The patent is called "fuel reforming system for vehicle," which doesn't do the engine justice, especially considering what it could mean to the industry. In a nutshell, this engine is built to make hydrogen from gasoline, using heat and a catalyst built within the engine's systems.
This new engine is designed to recover carbon, improve thermal efficiency, and result in a vehicle that runs carbon-neutral. It shouldn't be too surprising that Mazda came up with such an idea — the brand has been at the forefront of unconventional engine technology for decades, from the rotary Wanky engine to its proprietary SKYACTIV-X compression-ignition gasoline technology.
Is It A Hydrogen Or A Gasoline Engine?
The right answer is that this new Mazda six-stroke engine is both. It uses gasoline as fuel and separates the hydrogen from the carbon, using the hydrogen for the combustion process, which means the exhaust doesn't have CO2 in it. By burning the hydrogen and storing carbon, the engine burns gasoline without expelling harmful carbon dioxide into the atmosphere most of the time.
Only a small amount of hydrogen is stored, which means the engine doesn't require the same complex high-pressure tanks used in a dedicated hydrogen fuel-cell vehicle. When there isn't enough hydrogen ready for the engine, the new Mazda six-stroke engine can run on gasoline until there's enough hydrogen to do the job. During this transitional phase, the emissions would include carbon dioxide.
How Does The Mazda 6-Stroke Engine Work?
Additional Strokes Make Things More Complicated
Normal engines have four strokes, and that process has been used for decades. These four strokes are: intake, compression, power, and exhaust. This new Mazda engine adds two more strokes and redefines some of the movements to ensure carbon is removed from gasoline, allowing the engine to burn hydrogen and produce tailpipe emissions without carbon dioxide.
The six-stroke engine shares the same four strokes as a regular engine but adds two more. During the first cycle, air is pulled into the chamber — a normal first stroke. The next two strokes are also traditional in nature: compression and power. But things change when you get to the fourth stroke.
During the fourth stroke (or cycle, if you prefer), called the re-compression stroke, the exhaust air is pushed through a different valve, which sends it through a decomposer. The decomposer works like a catalytic converter but doesn't rely on expensive precious metals. In front of the decomposer is a fuel injector that introduces gasoline into the hot exhaust air.
The mixture of exhaust air and fuel enters the reformer, and the carbon sticks to the catalyst. This is the separation process, sending hydrogen to its small storage tank and the carbon to the carbon recovery unit.
Once the separation is completed, the fifth stroke occurs, called re-expansion. During this stroke, the remaining air re-enters the cylinder, which is then pushed out of the exhaust valve in stroke number six — the equivalent of the normal fourth stroke in most engines.
What Happens To The Carbon?
If your vehicle has a carbon storage tank, it will need to be emptied periodically. The carbon recovery unit would be drained when taking the vehicle in for service. The carbon, which is recovered in its pure form, has practical downstream uses — in steel manufacturing, as a pigment, or in other industrial carbon applications.
Advantages And Disadvantages Of Mazda's New 6-Stroke Engine
Advantages
The most obvious advantage is cleaner emissions from any vehicle powered by this new Mazda six-stroke engine. Without the added carbon dioxide entering the atmosphere, many environmental challenges could be lessened, including respiratory issues for some people, aspects of global warming, and urban smog.
Another significant advantage is the continued use of gasoline. This new engine would support the existing fueling infrastructure, which would reduce pressure on EV charging networks and the broader transition to electricity. Effectively replacing gas vehicles with EVs demands major improvements to the electrical grid, and those changes carry enormous costs.
Disadvantages
The six-stroke engine is considerably more complex than current four-stroke engines. It has more moving parts, more technology, and a far more intricate method of burning fuel. That complexity raises maintenance costs and creates the potential for more expensive repairs. By contrast, EVs have fewer moving parts than gas engines, which generally translates to lower maintenance bills.
A car's ability to effectively store carbon is another concern.
Each gallon of gasoline contains about 5.5 pounds of carbon. This means a 15-gallon tank would produce nearly 82.3 pounds of carbon — a significant amount of extra weight to carry around. On the positive side, that carbon isn't coming out of the tailpipe. Practically speaking, this could lead to carbon-emptying stations at gas stations, sparing drivers a trip to a dealer service center just to have the carbon tanks cleared.
How Efficient Is The Mazda Six-Stroke Engine?
This is new and unproven engine technology, which makes it extremely difficult to estimate how efficient the engine could be. With gasoline being introduced into the mixture later in the process, the engine could prove more or less efficient than a traditional gas engine. Efficiency is also hard to judge because the engine ultimately burns hydrogen — not gasoline — during the combustion process.
Possible Applications Of This New Mazda Engine
Future Mazda SUVs
Mazda has already embraced hybrid powertrains across its lineup and has shown a continued commitment to the rotary engine — even deploying it as a range-extender generator in its MX-30 R-EV plug-in hybrid. That willingness to pursue unconventional solutions makes Mazda's SUV lineup a logical proving ground for a new engine concept. The six-stroke engine would make particular sense in smaller vehicles operating in dense urban environments, where air pollution and smog caused by CO2 emissions are persistent problems.
Endless Possibilities, Maybe
Before figuring out where the Mazda six-stroke engine can be used, it first needs to be built and proven to operate with some level of efficiency. Many questions remain unanswered about this newly patented idea. How much will the added engineering and technology increase vehicle prices? How efficiently can this engine operate? What is the power output? How long does it take to accumulate enough hydrogen for the exhaust to become carbon-free?
Gas Instead Of Electricity
With the right answers to those questions, this new Mazda six-stroke engine could give the internal combustion engine a compelling future alongside — or even in competition with — EVs. Gas-fueled engines could live on for decades with this technology, but they would have to prove to be a meaningfully better choice than electricity. That means this engine would need to power vehicles that are practical, useful, affordable, and easy to live with — much like today's gas-powered cars, trucks, and SUVs.
The new Mazda six-stroke engine is a genuinely fascinating concept, but it may never move beyond the patent stage. Automakers routinely file patents to protect ideas that never reach production — the gap between an intriguing concept and a viable, manufacturable product is wide, and practical application has a way of humbling even the most promising engineering ideas.