Who invented Octane Ratings?
Since 1912 the spark ignition internal combustion engine’s compression ratio had been constrained by the unwanted “knock” that could rapidly destroy engines. “Knocking” is a very good description of the sound heard from an engine using fuel of too low octane. The engineers had blamed the “knock” on the battery ignition system that was added to cars along with the electric self-starter. The engine developers knew that they could improve power and efficiency if knock could be overcome. Kettering assigned Thomas Midgley, Jr. to the task of finding the exact cause of knock [16]. They used a Dobbie-McInnes manograph to demonstrate that the knock did not arise from preignition, as was commonly supposed, but arose from a violent pressure rise _after_ ignition. The manograph was not suitable for further research, so Midgley and Boyd developed a high-speed camera to see what was happening. They also developed a “bouncing pin” indicator that measured the amount of knock [7]. Ricardo had develope
