Design and Manufacture of a Formula SAE Variable Intake Manifold 2017-36-0181

Intake tuning and ram effect are widely known methods to increase engine performance. This paper details the design, manufacturing and results of an intake system with active duct length variation for a CBR600RR 2008 engine, equipped with a restrictor downstream of throttle body, in accordance due to Formula SAE competition rules. The engine was discretized in Gamma Technologies' GT-Power software bundle, and with the aid of the computational tool Design of Experiments (DoE), the lengths and diameters of the inlet ducts and beyond the plenum volume were determined in order to increase the engine torque in the range of 6000 to 12000 RPM. After the dimensioning process, the assembly was modeled in CAD, analyzing the packaging requirements determined by the regulation and a better adaptation of the system to the prototype, and then fabricated, including the plenum, restrictor and intake manifold. The plenum was made with composite material with the fiberglass /epoxy system due to the complex geometry. The other intake manifold sub-parts employed with aluminum, involving cutting and machining. The manufacturing process aimed an easy installation and maintenance of the system, in addition to the projection of a reduced mass to counter to the addition of parts that the active length variation system requires. With an electro-pneumatic actuation system, the intake duct length variation was tested in a chassis dynamometer to obtain the torque curves, verifying the real efficiency of the system. The methodology adopted in the project, simulations and the results obtained will be detailed in this paper. Results show that peak torque was changed to 58.5 Nm and shifted to 9000 rpm. Power was increased from 74 to 86 hp, shifting moving its peak from 10000 to 11000 rpm.