ENGINE MOUNT OPTIMIZATION BY PULSE LASER HOLOGRAPHY

During development of a prototype front-wheel-drive vehicle the high interior noise level throughout the RPM-range was criticised. In particular a 300 Hz noise between 4000 and 5000 RPM was disturbing. A graph shows the vehicle interior noise between 1800 and 5700 RPM at full throttle acceleration and idle deceleration. The peak was at approx 4500 RPM. As a result of investigations conducted in an anechoic chamber, it was concluded that this high noise level was caused by the 4th engine order. In addition it has been established by "strip-down" tests that the noise was transferred into the passenger compartment via the engine mount system. The conventional way to improve this situation is by "trial and error". To avoid these time consuming and expensive investigations with a large variety of sample-parts the "double pulse laser holography" method was applied. With this sophisticated technique the cause of the unwanted noise transfer was analysed in a very short time. The first part of the paper outlines the "pulse laser holography" method. Then the individual steps of the investigation of an engine mount system are explained. Finally the process of optimizing the engine mount system is presented and measured evidence of the noise improvement is given.

• Supplemental Notes:
  • ISATA 84, "In Pursuit of Technical Excellence". Proceedings Volume 1. International Symposium on Automotive Technology and Automation with particular reference to Vehicle Management Systems and Flexible Manufacturing Systems, Milan, Italy 24-28 September 1984.
• Corporate Authors:

  Automotive Automotion Limited

  42 Lloyd Park Avenue
  Croydon CRO 5SB, Surrey,   England 

  Alfa Romeo Auto SpA

  Milan,   Italy 
• Authors:
  • Kasperowski, M
  • Wiedow, D
• Conference:
  • ISATA 84, "In Pursuit of Technical Excellence". Proceedings Volume 1. International Symposium on Automotive Technology and Automation with particular reference to Vehicle Management Systems and Flexible Manufacturing Systems, Milan, Italy 24-28 September
• Publication Date: 1984

Media Info

• Features: References;
• Pagination: p. 691-706

Subject/Index Terms

• TRT Terms: Engine mounts; Front wheel drive; Holography; Lasers; Optimization; Sound level
• Old TRIS Terms: Engine mounting
• Subject Areas: Safety and Human Factors;

Filing Info

• Accession Number: 00399919
• Record Type: Publication
• Source Agency: National Highway Traffic Safety Administration
• Report/Paper Numbers: ISATA 84042, HS-038 460
• Files: HSL, USDOT
• Created Date: Oct 31 1985 12:00AM