In 1892, Akroyd Stuart patented a water-jacketed vaporiser to allow compression ratios to be increased. In the same year, Thomas Henry Barton at Hornsbys built a working high-compression version for experimental purposes, whereby the vaporiser was replaced with a cylinder head, therefore not relying on air being preheated, but by combustion through higher compression ratios. It ran for six hours—the first time automatic ignition was produced by compression alone.[citation needed] This was five years before Rudolf Diesel built his well-known high-compression prototype engine in 1897.[

Rudolf Diesel was, however, subsequently credited with the compression ignition engine innovation, despite Akroyd-Stuart’s engine being patented two years earlier. The higher compression and thermal efficiency is what distinguishes Diesel's patent, of 3,500 kilopascals (508 psi), from Ackroyd-Stuart's hot bulb compression ignition engine patent, of about 600 kilopascals (87 psi). Diesel improved his engine further, whereas Akroyd Stuart stopped development on his engine in 1893.