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China's GAC tests four-cylinder engine running on ammonia
Chinese carmaker GAC has explored a four-cylinder combustion engine powered by ammonia, a fuel that produces no carbon dioxide when burned, raising the question of why the company would pursue it.
By Edward Beaumont · 2 min read
Chinese carmaker GAC has explored developing a four-cylinder engine that runs on ammonia, a substance better known for its pungent smell than as a fuel for cars. The project raises an obvious question: why would a manufacturer want to power vehicles with a chemical most people associate with cleaning products and fertiliser?
The appeal lies in ammonia's chemistry. When burned, ammonia does not release carbon dioxide, the greenhouse gas produced by petrol and diesel engines. That makes it attractive to car makers looking for ways to keep internal combustion engines relevant as governments tighten emissions rules and push towards electrification. Ammonia can also be stored and transported more readily than hydrogen, which must be kept under extreme pressure or at very low temperatures.
Running an engine on ammonia is not straightforward. The fuel burns more slowly and with less energy per unit volume than petrol, and it can produce nitrogen oxides, pollutants that must be controlled through careful engine design and exhaust treatment. Engineers therefore face a trade-off between cleaner combustion and performance, a challenge that has kept ammonia largely confined to research and marine and power-generation applications rather than passenger cars.
GAC's work reflects a broader search across the industry for alternatives to batteries and conventional fuels. Several manufacturers and research groups have examined hydrogen, synthetic fuels and ammonia as possible routes to lower-carbon transport. Whether an ammonia-fuelled passenger car can move beyond prototype stage will depend on the cost of producing green ammonia, the availability of refuelling infrastructure and the outcome of ongoing emissions testing.
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