Sound Quality Engineering of a New Transport Refrigeration Unit

The redesign of a diesel driven transport refrigeration unit is described, with focus on sound quality goals. Acoustic level and quality goals were set with customer feedback based on jury tests. Sound source levels of specific components were identified, with the noise level of the diesel intake and exhaust, the condenser fan, and noise of the gearbox having the most impact on sound quality. A post-design jury test confirmed the effectiveness of the redesign effort.