Development of 2D measurement system of dissolved air distribution in AT fluid using pressure-sensitive paint

Abstract

Dissolved air in the working oil (Automatic transmission fluid: AT fluid) can cause problems by generating cavitation, which erodes the surfaces of parts, and bubbles. Therefore, it is important to measure the concentration of dissolved air in AT fluid. In recent years, there has been a need to measure the distribution of dissolved air concentration. The dissolved air in AT fluid can be estimated by measuring the dissolved oxygen (DO). However, conventional DO meters are point sensors that measure DO by placing the probe in oil and hardly obtain the 2-D distribution of it. In this study, we have developed an optical DO measuring technique using a pressure-sensitive paint (PSP) to capture the 2-D distribution of the DO in AT fluid. A newly developed oil-resistant PSP was able to measure the temporal variation in the distribution of dissolved air with high spatial resolution.