Design, Analysis and Optimization of SI Engine Intake Manifold for FSAE 2018-32-0073
Fluid dynamics of intake system plays a key role in deciding the performance of an engine. This dynamics is different for fuel injected and carburetted engine and varies according to type of engine, number of cylinders, temperature at inlet, valve timing, valve angle and other factors. Careful design of the intake manifold enables to manipulate the performance characteristics of the engine to the desired level.
The present work deals with the analysis of the flow within the intake manifold in steady state and analyze the results to evaluate and improve the ability of the intake port to convey air to the cylinder with the highest possible mass flow rate. Enhanced mass air intake increases the breathability of the engine which in turn increases the volumetric efficiency of the engine. Optimising air flow performance during intake process is the main objective of this work.
The performance of the engine can be improved by optimized design of intake manifold. In the process of optimizing the flow for improving engine performance, computational fluid dynamics (CFD) simulation plays a very important role. This paper will discuss the 3-D simulation of intake manifold of KTM Duke 390cc engine. Steady state analysis has been done using ANSYS FLUENT.
The intake manifold of the above engine has certain engine power restrictions (imposed by Formula SAE rule book) and there is a 20mm restrictor present between the throttle body and engine cylinder. To achieve stagnation of air, plenum is used. Runner connects the plenum with engine and is tuned at certain rpm to optimize engine performance. As KTM 390 Duke engine was used for the competition, all analysis was done on three parts – Restrictor, Plenum and Runner. Optimized design of intake manifold would achieve pressure inside the engine cylinder slightly greater than atmospheric (at the start of compression stroke) even with above mentioned restrictions.