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The development of fuel systems components are becoming challenging with the increasing use of Biofuels like Biodiesels and Ethanol around the world. Biodiesels are one of the most challenging fuels, once they can have multiple sources, which influences its characteristics, mainly the oxidization stability and peroxide levels. As the fuel characteristics changes along the time, the correct materials selection during the development phase is very important for the fuel system performance during the vehicle lifetime. One of the components most affected by the Biodiesel is the in tank fuel pump system. During the vehicle lifetime, it is exposed to all sorts of fuel and its contaminants and exposed to system stress factors like temperature and voltage variation. The wires insulation in the fuel pump systems are one of the most affected components.

One of the usual measures to increase the energy efficiency in automotive vehicles has been the adoption of generators with variable voltage systems, commanded by the vehicle control unit. Thus, the vehicle system voltage no longer remains constant during operation of the engine, but becomes variable as needed to charge the vehicle electrical system and better use of available engine torque. A study using the Design for Six Sigma (DFSS) methodology was performed in order to understand the influence of the supply voltage and of the fuel conductivity in the lifetime of fuel pump commutation system by brushes. Durability tests were conducted in bench test, where parameters of temperature, current draw, voltage and fuel conductivity were monitored, correlating them with the results of wear in the pump commutation system.