A new zero-emissions engine capable of competing commercially with hydrogen fuel cells and battery electric systems appeared on the radar yesterday when respected British engineering consultancy Ricardo validated Dearman engine technology and its commercial potential. The Dearman engine operates by injecting cryogenic (liquid) air into ambient heat inside the engine to produce high pressure gas that drives the engine – the exhaust emits cold air. It’s cheaper to build than battery electric or fuel cell technology, with excellent energy density, fast refuelling and no range anxiety.

Think of the Dearman engine as an internal combustion engine without a spark plug, with cryogenic liquid air injected instead of petroleum. There is no combustion, but because the air is stored at cryogenic temperatures (sub minus 160 degrees Celsius), ambient temperatures can superheat it and return it to gaseous form, causing a rapid expansion of gases.

When the piston is at the top of the cylinder, some heat exchange fluid is admitted to the engine cylinder. Immediately after this a small quantity of cryogenic liquid is sprayed into the cylinder; it comes into contact with the ambient (but in relative terms to the cryogenic temperatures, super hot) heat exchange fluid and boils very rapidly, building […]