The Fraunhofer Institute and the startup First Ammonia Motors adapted a 1990s V8 engine to run on ammonia, emitting only nitrogen and water vapor. The technology still faces challenges of high cost and consumption.
A conventional combustion engine running without a drop of oil and without emitting carbon dioxide. What seemed distant has just taken concrete form: the Fraunhofer Institute for Microtechnology and Microsystems (IMM), in Germany, in partnership with the American startup First Ammonia Motors (FAM), presented a technology capable of making a traditional gasoline engine operate with ammonia as fuel.
As reported by the Xataka website, the novelty emerges in a context of global pressure for alternatives to conventional oil, combining instability in the Middle East with greenhouse gas emission reduction targets.
How does an ammonia-powered engine work?
Ammonia — identified by the chemical formula NH₃ — is a gas composed of three hydrogen atoms for each nitrogen atom. Although not a new idea as a fuel, it has always encountered a significant technical obstacle: its ignition temperature is very high, which made direct operation in conventional engines difficult.
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Previously, the adopted solution was to mix ammonia with diesel or methanol to enable combustion. What IMM and FAM did was precisely solve this bottleneck differently. In the system developed by the two entities, when the engine is started, unburnt ammonia that would exit through the exhaust undergoes a decomposition process.
The hydrogen released in this process is then reinjected directly into the engine, acting as an ignition additive. Being more flammable than pure ammonia, it allows the engine to start and operate normally.
From then on, the engine operates emitting only nitrogen and water vapor — a significantly lower level of pollution than that generated by burning gasoline or diesel.
The test engine: a 1990s V8
To validate the technology, researchers used a 6.6-liter Chevrolet V8, a 1990s model, installed in a Chevrolet C10 pickup truck. Under test conditions, the engine behaved as if it were being fueled with regular gasoline — with a considerable difference in consumption.

Having an energy density 50% lower than that of gasoline, ammonia requires a larger amount of fuel to be injected to generate the same power. In practice, this caused the vehicle’s consumption to double compared to the original.
To compensate and maintain acceptable autonomy, the C10 used in the tests began to carry double the fuel capacity compared to its original gasoline tank.
Advantages and limitations of this engine technology
The proposal from FAM and IMM presents relevant positive points, but also challenges that cannot be ignored:
Advantages:
- Total elimination of CO2 emissions during engine operation
- Utilization of existing combustion engine infrastructure
- Refueling time equivalent to gasoline, according to the company
- Possibility of producing green ammonia from renewable sources
Limitations:
- Double fuel consumption compared to gasoline
- Lack of refueling station network in the US and Europe
- High cost of ammonia production
- Production process that requires prior generation of hydrogen and nitrogen separately
- High energy consumption in the fuel manufacturing process
Why is ammonia expensive to produce?
Producing ammonia is not simple. The process first requires obtaining two separate gases—hydrogen and nitrogen—which are then combined. Hydrogen can be extracted from water through electrolysis, while nitrogen is taken from the atmospheric air itself.
Although both processes are technically viable, they demand a large amount of energy, which increases production costs and compromises the overall energy efficiency of the cycle. Even when produced green — that is, using renewable sources — ammonia is still expensive.
FAM itself recognizes the challenge and, with a certain implicit skepticism, bets on the future rise in gasoline prices as a factor that would make ammonia economically competitive over time.

An uncertain, but possible future
The startup plans to commercialize a device capable of converting conventional gasoline engines to operate with ammonia. However, in addition to the high cost of the fuel, the high consumption and the low estimated yield in the production process raise doubts about the economic viability of the technology on a large scale.
On the other hand, in the scenario of alternatives to fossil fuels, ammonia is not alone in the dispute.
Hydrogen, often pointed to as the solution of the future, also faces criticism — and major manufacturers like Stellantis have already slowed down research in this area. Few automakers still maintain firm bets on this technology, which illustrates how much the sector is still seeking a clear path for the decarbonization of internal combustion engines.
Source: Xataka

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