An engineering team at AVL Racetech has unveiled an internal combustion engine that runs primarily on hydrogen and uses precisely metered water injection-not petrol or diesel. 400 PS, 6,500 rpm, and none of the familiar soot-laden exhaust plume: it sounds like science fiction, yet it is positioned as a direct counterpoint to today’s dominance of the electric car.
What the new “water engine” actually is
First, a necessary clarification: this is not a perpetual-motion machine that drives on tap water alone. At its heart sits a hydrogen internal combustion engine, enhanced by a carefully engineered water system designed to make combustion steadier, cleaner and more powerful.
AVL Racetech, a company focused on high-performance powertrains, brings three elements together:
- Hydrogen as the primary energy carrier
- A turbopump that injects heated water at high pressure
- A combustion layout engineered to reduce knock tendency and prevent damage
The message the team wants to send is straightforward: internal combustion engines do not have to be tied to fossil fuels. Familiar hardware inside the engine block is paired with a very different way of “feeding” it-H₂ and water instead of premium unleaded.
"The engine uses hydrogen as fuel, water as a stabiliser, and aims to make the classic exhaust cloud unnecessary."
The technical concept: hot water to tame overheated cylinders
Hydrogen engines have a known weak point: combustion behaviour. Hydrogen ignites readily and can “pre-burn” uncontrollably, which risks damaging pistons or valves. This is exactly where the water system is intended to intervene.
How the water injection is meant to help (AVL Racetech hydrogen engine)
AVL Racetech’s turbopump forces heated water into the combustion chamber. That injection is intended to trigger several effects at once:
- Combustion temperature drops slightly, smoothing out peaks.
- The pressure curve becomes more even, reducing stress on components.
- The resulting steam volume supports expansion-effectively like a mini steam turbine inside the cylinder.
The aim is to extract more performance from hydrogen without destroying the engine in the process. The developers cite 400 PS and up to 6,500 rpm-figures comparable with the output range of many modern mid-range to executive-class petrol engines.
Advantages compared with conventional hydrogen systems
In hydrogen discussions, the fuel cell has often been treated as the front-runner: hydrogen is converted into electricity, which then drives an electric motor. This new approach deliberately returns to the combustion principle-while arguing it has several practical strengths:
- Established manufacturing processes for engine blocks and auxiliaries
- Familiar servicing concepts for workshops
- Potential for high continuous power, for example in heavy-duty applications
- Fewer critical raw materials than are needed for very large batteries
In the best-case scenario, the engine runs on green hydrogen produced using renewable energy. In that case, operational CO₂ emissions are effectively negligible, with the exhaust primarily consisting of water vapour.
Are electric-car weaknesses an opening for this new engine?
The timing of the reveal is not accidental. Electric-car registrations are rising in many places, but the list of recurring criticisms continues to grow:
- Long charging times in daily use and on longer journeys
- Uncertainty around real-world winter range
- High resource demand for batteries (lithium, cobalt, nickel)
- Unresolved questions about end-of-life battery disposal
"The new engine targets the weaknesses of battery cars: range, charging time, raw materials."
A hydrogen internal combustion engine with water injection could, in theory, score points here:
- Refuelling in minutes rather than charging for hours
- Consistent power delivery even under high load and at low temperatures
- No gigantic battery required-meaning less mass and fewer scarce raw materials
At the same time, it preserves the familiar driving feel of a combustion engine-an often underestimated psychological factor for many drivers.
What is still completely unclear
However impressive the paper figures look, the decisive test has yet to happen: everyday use. So far there are prototypes and dyno results, but no fleet racking up high-mileage service.
The hurdles on the road to series production
Three barriers stand out in particular:
- Green hydrogen: The concept only makes real sense if the hydrogen is produced in a climate-neutral way. At present, large volumes still come from natural gas.
- Filling-station network: Hydrogen pumps remain scarce in Germany and Austria. That is not sufficient for a mass market.
- Cost and durability: Turbopumps, injection hardware and high-pressure systems must become cheaper while reliably lasting 200,000 kilometres and more.
Industry is therefore facing a strategic question: is it worth developing another fundamentally different powertrain when billions are simultaneously flowing into battery cars, charging infrastructure and fuel cells?
A look back: why the “water idea” keeps returning
The dream of driving “on water” has been part of engineering folklore for decades. Various manufacturers have experimented with water injection-BMW, for example, used it in high-performance engines to reduce knock and enable higher output.
What is new in the current development is the uncompromising pairing of hydrogen as the energy carrier with water as a tool for combustion control. Rather than chasing a few percentage points of efficiency, the goal is a complete powertrain concept intended to be viable in everyday use.
| Powertrain | Energy source | Strengths | Challenges |
|---|---|---|---|
| Battery electric car | Electricity from battery | High efficiency, quiet operation | Charging time, raw materials, range |
| Fuel cell car | Hydrogen, electricity from fuel cell | Fast refuelling, good range | Expensive technology, few filling stations |
| Hydrogen “water engine” | Hydrogen + water injection | Familiar engine technology, high continuous power | Efficiency, durability, H₂ production |
What consumers can realistically expect
Anyone thinking of selling their electric car right now is acting too soon. It only becomes a genuine threat to the current EV wave once several conditions are met:
- Series readiness and manufacturer approval
- A significantly lower CO₂ balance over the full lifecycle than battery cars
- Acceptable cost per mile, including the price of refuelling with green hydrogen
- A noticeable expansion of the hydrogen filling-station network
A coexistence of powertrains is the more likely outcome. City cars and commuters may stick with batteries, while long-distance transport, large SUVs, vans or lorries may turn to hydrogen concepts-either fuel cell or internal combustion with water injection.
Technical background that often gets overlooked
Efficiency: why this engine has to fight hard
Battery-electric drivetrains set the benchmark for efficiency. Losses occur from generation to the wheels, but within the vehicle itself 70 to 80 per cent is common. Conventional internal combustion engines are typically well below 40 per cent.
That means the new hydrogen “water engine” has a lot of ground to make up. If water injection improves efficiency, it could at least move closer to modern diesels. Ultimately, climate impact comes down to one question: how much renewable energy is required per kilometre travelled? The closer the engine gets to battery systems on that measure, the more interesting it becomes for fleet operators.
Safety and handling of hydrogen
Hydrogen is light, diffusive and flammable. Modern tank systems are robust, incorporate multiple safety layers and are tested for crashes, fire and ballistic penetration. Even so, a residue of public mistrust remains.
A production vehicle using a hydrogen internal combustion engine therefore has to do more than be technically safe-it must also build confidence through clear labelling, transparent testing and training for workshops and emergency services.
Why this development still puts pressure on the electric-car industry
Even if this engine never becomes a mass-market phenomenon, it sends a clear message: the future is not locked to a single technology. Manufacturers that have committed exclusively to batteries will have to explain how they intend to respond to credible alternatives.
At the same time, competition intensifies for policy support, infrastructure investment and public attention. If a hydrogen “water engine” proves distinctly superior in certain segments-such as motorsport, heavy-duty use or large motorhomes-pure battery concepts will face greater pressure to become more efficient, cheaper and more practical in everyday conditions.
For consumers, that means the powertrain question remains open. AVL Racetech’s latest engine is not a finished miracle cure, but it is another serious contender in the race for cleaner mobility.
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