Combined velocity and temperature imaging of gas flow in an engine cylinder.

A combined velocity and temperature measurement method using a high-speed camera, a pulsed UV laser, and temperature-sensitive phosphor particles is proposed. The temperature was calculated from the phosphorescence lifetime, while the velocity was obtained from images of the phosphor particles during a single decay. This method was applied to in-cylinder measurements of gas flow at high temperatures under motoring conditions. Tumble flow was observed at the top dead center. The temperature-change dependence on the crank angle agrees qualitatively with the gas temperature and the pressure.