Development of Optimisation Methodologies for the Internal Combustion Engine Airbox

  • Ciaran Branney

Student thesis: Doctoral ThesisDoctor of Philosophy


The geometrical design of the airbox for an internal combustion engine has a
significant effect on the pressure loss in the entire inlet tract. Due to the
location of the airbox, its size and shape is usually limited as a result of the
proximity to other under-bonnet features. The shape is also limited by
manufacturing, assembly and NVH considerations. The complexity of the
unsteady flow through the airbox and the constraints placed upon it by the
available volume in the under-bonnet area make this a challenging design

This work attempts to lay the foundations for a robust optimization strategy for
the design of an airbox by coupling a 3D-steady flow Computational Fluid
Dynamics (CFD) model to an automatic optimization process. The objective is
to formulate a strategy that can be built upon in future to encompass unsteady
flow and multi-cylinder engines.

The work reviews the current thinking on methods used to optimize CFD
problems and how this would apply to the optimization of an airbox for an
internal combustion engine. The investigation then continues to detail the
findings of the initial validation work on the CFD method for predicting the
pressure loss through an airbox. Two simple airboxes are tested on a steady
flow rig and the results compared to the CFD predictions.

An optimization case study is then presented based on one of the models
used for the initial validation. The study compares three different optimization
techniques and then validates the results by testing the optimum design found
by each method. A second case study is then undertaken to further validate
the results using more flexible optimization software.
Date of Award2009
Original languageEnglish
Awarding Institution
  • Queen's University Belfast
SupervisorGeoff Cunningham (Supervisor)

Cite this