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

Welch, Cooper and Schmidt, Marius and Keskinen, Karri and Giannakopoulos, George and Boulouchos, Konstantinos and Dreizler, Andreas and Böhm, Benjamin (2020):
The Effects of Intake Pressure on In-Cylinder Gas Velocities in an Optically Accessible Single-Cylinder Research Engine.
In: WCX SAE World Congress Experience. SAE Technical Paper 2020-01-0792,
Detroit, SAE International, ISSN 0148-7191, e-ISSN 2688-3627,
DOI: 10.4271/2020-01-0792,
[Conference or Workshop Item]

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.

Item Type: Conference or Workshop Item
Erschienen: 2020
Creators: Welch, Cooper and Schmidt, Marius and Keskinen, Karri and Giannakopoulos, George and Boulouchos, Konstantinos and Dreizler, Andreas and Böhm, Benjamin
Title: The Effects of Intake Pressure on In-Cylinder Gas Velocities in an Optically Accessible Single-Cylinder Research Engine
Language: English
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.

Title of Book: WCX SAE World Congress Experience. SAE Technical Paper 2020-01-0792
Place of Publication: Detroit
Publisher: SAE International
Divisions: 16 Department of Mechanical Engineering
16 Department of Mechanical Engineering > Institute of Reactive Flows and Diagnostics (RSM)
Date Deposited: 23 Jul 2020 05:37
DOI: 10.4271/2020-01-0792
Official URL: https://doi.org/10.4271/2020-01-0792
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