Study of the Transient Behavior of Turbocharged Diesel Engines Including Compressor Surging Using a Linearized Quasi-Steady Analysis

Abstract

The transient operation of turbocharged diesel engines during turbocharger compressor surging is investigated through simulation. This form of compressor dynamic instability can generate large amplitude compressor mass flow and pressure rise oscillations, sometimes leading even to flow reversals, and may also induce severe torsional loading to the turbocharger shaft. A model predicting the dynamic behavior of the engine aircharging system when compressor surging occurs was developed in conjunction with a linearized quasi-steady diesel engine simulation code. This analysis possesses the advantage over the more detailed engine codes of basic simplicity, speed of calculation and no need of many engine and turbocharger components parameters given as input data. Emphasis is given to the correct modeling of the physics of the phenomena concerned. Transient operation runs, including critical cases for surging initiation, were applied for two similar six-cylinder diesel engines. The first one is a Ruston & Hornsby engine for light duty automotive diesel applications, while the second one is a MWM marine duty diesel engine. By analyzing simulation results, the effect of the engine inlet manifold volume and the compressor air duct length on the phenomenon of surging is studied.