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System and Method for Measuring Engine to Vehicle Interior Noise Reduction

IP.com Disclosure Number: IPCOM000012400D
Publication Date: 2003-May-05
Document File: 2 page(s) / 64K

Publishing Venue

The IP.com Prior Art Database

Abstract

Engine to interior noise reduction transfer functions must be measured to evaluate and optimize vehicle sound package design. The accuracy of the transfer function measurements depends on how accurately the acoustic properties of the engine compartment are preserved. The conventional engine noise simulator method requires the removal of the engine and installation of a speaker box in the engine compartment to simulate an engine radiated sound field.

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                         System and Method for Measuring Engine to Vehicle Interior Noise Reduction

Engine to interior noise reduction transfer functions must be measured to evaluate and optimize vehicle sound package design. The accuracy of the transfer function measurements depends on how accurately the acoustic properties of the engine compartment are preserved. The conventional engine noise simulator method requires the removal of the engine and installation of a speaker box in the engine compartment to simulate an engine radiated sound field.

A measurement system and test method are proposed to use a point sound source at the driver and passenger ear locations while measuring microphone Sound Pressure Level (SPL) responses in the engine compartment. This system and method preserves the engine compartment acoustic properties by keeping the actual engine in place and it saves time and associated cost for engine removal.

System and Method

The system employs a portable high frequency omni-directional point sound source. White noise is generated at the base of the source and propagated through a rubber hose to a nozzle. Sound generated at the nozzle is omni-directional. The frequency range of the sound source is 200 to 10,000 Hz. This source has an integrated signal generator and power amplifier. The spectrum of the source is capable of generating Sound Pressure Level (SPL) in 1/3 octave frequency bands at 1 meter distance as shown in Figure 1.

Figure 1. Point Sound Source

SPL of Sound Source at 1 Meter

90

80

70

60

SPL (dB)

50200 250 315 400 500 630 800 1000 1250 1600 2000 2500 3150 4000 5000 6300 8000 10000

1/3 Octave Frequency (Hz)

The...