Motorcycle exhaust systems


Project background

Bos Exhaust systems is a major manufacturer of exhaust pipes for motor cycling and scooters. Physixfactor and Bos collaborated in the field of product development, with the main goal to accelerate the design and production process of exhaust systems (exhaust pipes).

  • Bos produces exhaust systems which comply with the latest EU sound and environmental regulations.
  • Up to now expansive trial and error methods were the basis of new exhaust pipes.
  • The time to market from the design to mature product is over 6 months.

Project goal

  • Simulate the absorption and the average sound level of an exhaust pipe.
  • Determine the influence of the position of inner plates and pipes on the sound level and absorption.
  • Deliver new product within 4 weeks.


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FEM simulation

FEM (Finite Element Method) is very well suited for determining the properties of resonators, like exhaust systems. With FEA one is able to simulate the sound absorption and entire absorption spectra of a variety of resonator designs. Even the volume flow of the hot gases can be studied as a function of several design parameters. Vortices in the flow field inside the resonator could be the source of extra unwanted noise, and the virtual models in the computer can reveal the place and strength of those vortices in your new designs.

  • The new exhaust system can be implemented in 3D in the  computer.
  • With FEM simulations the acoustical properties of your design can be determined.
  •  Once in the computer, you are able to improve the design in a few simulation cycles. No prototypes anymore!
  • The coupling of vibrating inner panels become immediately clear.


The work for Bos resulted in a better positioning of some inner panels. Better sound performance and power development of the scooter.  By means of simulation technology one is able to produce virtual prototypes, and apply all kind of test cycles in the computer. Also the damping material can be applied on several place in the virtual model to determine the optimal position and thickness. In his way one is able to surpass the trail and error step.

  • This workflow reduces the time to market at Bos significantly.
  • To to market has been reduced from 6 months, to 4 weeks!