The Effects of Intake Pressure on In-Cylinder Gas Velocities in an Optically Accessible Single-Cylinder Research Engine

Cooper Welch*, Marius Schmidt, Karri Keskinen, George Giannakopoulos, Konstantinos Boulouchos, Andreas Dreizler, Benjamin Boehm

*Corresponding author for this work

Research output: Contribution to journalConference articleScientificpeer-review

3 Citations (Scopus)

Abstract

Particle image velocimetry measurements of the in-cylinder flow in an optically accessible single-cylinder research engine were taken to better understand the effects of intake pressure variations on the flow field. At a speed of 1500 rpm, the engine was run at six different intake pressure loads from 0.4 to 0.95 bar under motored operation. The average velocity fields show that the tumble center position is located closer to the piston and velocity magnitudes decrease with increasing pressure load. A closer investigation of the intake flow near the valves reveals sharp temporal gradients and differences in maximum and minimum velocity with varying intake pressure load which are attributed to intake pressure oscillations. Despite measures to eliminate acoustic oscillations in the intake system, high-frequency pressure oscillations are shown to be caused by the backflow of air from the exhaust to the intake pipe when the valves open, exciting acoustic modes in the fluid volume. This phenomenon is much stronger in the throttled-load cases because of the high differential between exhaust and intake gases. In addition, 1-D simulations of the engine at varying intake pressures and pipe geometries provide insight into the interactions between the pressure variations, high-frequency oscillations, and intake flow.

Original languageEnglish
JournalSAE Technical Papers
Volume2020-April
Issue numberApril
DOIs
Publication statusPublished - 14 Apr 2020
MoE publication typeNot Eligible
EventSAE World Congress Experience - Detroit, United States
Duration: 21 Apr 202023 Apr 2020

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