NVH Design and Refinement of Dedicated Hybrid Engine on Range Extender Electric Vehicle

Traditional NVH (Noise, Vibration, Harshness) refinement is reactive, addressing issues post-prototype. In contrast, this work establishes NVH as the primary driver in early engine development for range extender electric vehicles (REEVs). Customer demands for imperceptible engine operation [1] - intensified by absent masking noise in electrified powertrains [2] - necessitate a proactive methodology: Usage-Driven Operating Profile: Analysis of >500,000 km fleet driving data identified statistically dominant operating conditions. This enables precise NVH focus areas and proactive avoidance-zone definition in the engine operational map. Vehicle-Driven Target Setting: Subsystem-level NVH targets (e.g., <58 dB(A) idle noise → engine-level) were rigorously derived from vehicle imperceptibility requirements and the dominant usage profile. Preventive Design Optimization: Architectural choices (stiffness-enhanced bedplate block), component tuning (crankshaft/flywheel dynamics), and subsystem solutions (fuel-system countermeasures) were optimized upfront for high-likelihood operating points. Results validate the approach: Idle noise: 57.5 dB(A) (4-mic avg. vs. program target 58 dB(A) and industry benchmark of 62 dB(A) [4]). 42% reduction in crankshaft torsional modulation depth. Elimination of fuel-injector ticking. NVH robustness was confirmed across dominant real-world driving modes. By shifting NVH from late-stage remediation to usage-informed upfront design, this process reduced development iterations by 40% (vs. previous ICE/HEV programs) and mitigated field-failure risk in high-exposure operating conditions.