An Approach Towards Design of Plastic Fuel Rail for Automotive Application 2019-26-0164
As India has decided to move to BS VI emission regulation by 2020, all original equipment manufacturers (OEM) and Tier 1 suppliers are working towards achieving the goal to be in the business. Weight reduction is a key area; where in, contribution of green house gas emissions can be significantly reduced. In a conventional Multi Point Fuel Injection (MPFI) engine, a fuel rail/ delivery pipe is mounted on the intake manifold or cylinder head delivers fuel to inlet port at a fuel pressure of 350 kPa to 400 kPa through fuel injectors.
In today’s automotive industry most of the fuel rail components are made from aluminium because of its ease of availability and machinability. Reduction in fuel rail material weight leads to significant effect on fuel economy and hence reduction in green house gases. It also helps in reduction of cost of the part. Therefore, several studies have focused on alternate materials like sheet metal and plastic by reducing the weight of the fuel rail. One another advantage of plastic material is that naturally that it can dampen the fuel pressure fluctuations. Hence, a separate pressure pulsation dampeners is not required as in the case of aluminium material fuel rail.
In this work, by use of optimization of design verified with CAE analysis, concept is created and proto samples of plastic fuel rail were made and tested for target strength and durability. Design characteristics were investigated with respect to the aspect ratio of the cross-section, wall thickness and different grades of material suitable for this application. Also, end sealing are designed for hermetically joints such that hence are leak proof along with Ultrasonic welding. For proper sealing to withstand high fuel pressures, different joint types and energy directors are studied evaluated to arrive at optimum design. The final sealing thus arrived can withstand a burst pressure of 2000 kPa. Finally, this study has resulted in reduction of weight by 2/3rd and cost by 50% meeting the performance and durability test requirements.