Engine Acoustic Impedance Modeled as a Cyclic Series of Passive System Impedances

Item

Title
Engine Acoustic Impedance Modeled as a Cyclic Series of Passive System Impedances
Date
1981
Index Abstract
Coming Soon
Photo Quality
Complete
Report Number
AFWAL TR 80-4203
Corporate Author
Materials Laboratory
Laboratory
Materials Laboratory
Extent
133
Identifier
ADA103931
Access Rights
Approved for public release; distribution unlimited.
Distribution Classification
1
Contract
Laboratory Research - No Contract
DoD Project
None Given
DoD Task
None Given
DTIC Record Exists
No
Distribution Change Authority Correspondence
None
Distribution Conflict
No
Abstract
The objective of this project was to utilize a recently proposed two sensor sampling technique for attaining certain acoustic properties of an internal combustion engine. Particular interest will be in attempting to define the acoustic source impedance characteristics of an internal combustion engine. The two sensor method of analysis incorporates a Digital Signal Analyzer system to analyze the sensor signals and to calculate incident-reflected acoustic properties. The laboratory method of experimentation includes exposure of the engine to a broadband random noise while performing signal analysis using a transfer function technique. The acoustic source impedance results obtained from this analysis for the engine are then interpreted within a format of passive acoustic systems. It was a hypothesis of this experimentation that the operating engine can be modeled as a series of cyclic passive systems. This hypotheses has been assessed from experimental results obtained from impedance studies of the motored and powered engine. Modeling of the engine as a cyclic series of passive systems was found to be quite useful for interpreting experimental acoustic impedances for motored engines. This acoustic engine model was found to be less applicable for powered engine studies.
Report Availability
Full text available
Date Issued
1981-07-01
Provenance
IIT
Type
report
Format
1 online resource
Creator
Lagnese, Thomas J., Jr.
Media
AFWALTR80-4203.pdf