New Engine Tunnel Insulation System for Commercial Trucks

Two new engine tunnel insulation systems were developed with 3M proprietary ThinsulateTM materials. One was a standard composite tunnel liner to replace fiberglass composite liner; another was a premium tunnel liner to replace fiberglass liner and decoupled foam barrier cover. In the process to design the new insulation systems, a full SEA sleeper truck model was used for a DOE analysis for a variety of materials and their combinations. Then the selected tunnel systems based on analytical DOE study were evaluated for sound transmission loss performance per ASTM E90. Meanwhile, system level thermal performance was assessed per ASTM C518 for material thermal conductivity and HTTR (High Temperature Test Rig) for composite touch temperature. Finally two newly designed tunnel systems were recommended.