Hydrogen and Nitrogen technology for engines

Just sharing an interesting article, comparing technologies. I had never heard of using Nitrogen, interesting. The Dearman difference engine. Happy reading!

http://www.economist.com/blogs/babbage/ ... ogen-cycle

An invention made by an independent British engineer called Peter Dearman dispenses with the costly heat exchanger that is needed to vaporise the liquid nitrogen quickly. Instead, a small amount of water and anti-freeze (eg, methanol) is injected into the cylinder just as the liquid nitrogen is drawn in, causing it to boil and expand rapidly—thereby forcing the piston down inside the the cylinder. “Without that,” says Mr Dearman, “you had to have a multi-stage engine, which is cumbersome, inefficient and expensive.”