Influence of firewall assembly sound insulation performance on vehicle interior noise

This study establishes a statistical energy model for a vehicle to evaluate and optimize the acoustic performance of its firewall pass-through components. The “window method” was applied to calculate the contributions of the firewall assembly, dash inner, and individual pass-through components to overall sound transmission. The sound insulation performance and coverage of these components were optimized. Prototype samples were developed and validated under real-world operating conditions at 60 km/h. The optimized design reduced the sound pressure level in the driver’s right ear by 1.1 dB (A), improved the articulation index (AI) by 2.8%, and achieved spectral energy reductions of 1–2.9 dB (A). These findings provide valuable insights into the design and setting of acoustic performance targets for firewall pass-through components in future vehicle models.