Phosphor thermometry was employed to measure the temperature distribution of the exhaust valves in an optically accessible direct injection internal combustion engine. A CMOS high-speed camera was used to twodimensionally resolve the temperature dependent luminescence decay of the phosphor Gd3Ga5O12:Cr. Measurements were performed under motored and fired conditions for several degrees crank angle to determine the temperature distributions within cycles. Additionally, several binders have been tested in terms of survivability and signal strength to guarantee ideal phosphor coating. N.