Glow and diesel (Thanks spell checker) are not the same. Diesel uses a variation of gasoline. It sucks in AIR (not an air/fuel mix) and has extreemly high compression. Once it reaches max compression, fuel is SLAMMED into the cylinder (That's that god-awful knocking sound you hear from big trucks). The high compression heats the air to the point where the fuel is immediately ignited upon injection.

The Glow Plug in a diesel engine is only used for cold weather starts when the heat of compression needs a little help.

A Glow Fuel Engine works through a chemical reaction between the fuel and the Platinum filament in the plug. Heat only augments the reaction.