Learn Automotive Design for Noise Vibration Harshness

A: The right call removes a narrow-band boom tied to idle firing by restoring frequency-dependent isolation; B would show wheel and column shake scaling with road speed, C would add higher-frequency content and persist off-idle, and D shifts with airflow and throttle rather than engine speed.

A: This choice keeps stiffness and loss factor stable under heat and oil; B swells and softens in oil, C hates hydrocarbons despite ozone strength, and D survives heat but sacrifices tear strength and damping under load.

A: The fix attacks excitation at the source by reducing RFV-unbalance coupling; B shifts alignment and can amplify nibble, C hides feel but worsens phase lag and safety margin, and D moves stiffness higher and often increases force transmission.

A: This standard translates seat vibration into human exposure metrics; B targets machines not occupants, C prevents imbalance not comfort issues, and D frames durability loads rather than ride perception.