Characterization of the noise and vibration patterns of the vehicle hvac system under various operating condition
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Date
2018-07
Authors
Muhammad Hidayat Hamdan
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Abstract
Noise and vibration have imperative impact on customer perception of vehicle quality
and cabin interior noise levels are some vital measures. One of the highest in-cabin noise
levels now arises from heating, ventilating and air conditional (HVAC) systems. The
HVAC noise is a common problem for most of the automotive manufacturers. In this study,
the HVAC noise problem is investigated for Proton Exora vehicle. Proton Exora is a multi purpose type vehicle (MPV) which induced a considerable HVAC noise level compared to
the other Proton vehicles. Regarding to this issue, this study aims to investigate the source
of the HVAC noise for both vehicle and system level by a proper characterization of the
noise and vibration patterns of the vehicle HVAC system under various operating system.
First, the study is carried out for vehicle level where the noise and vibration of HVAC
system are measured and analysed directly on real car. Whereas for system level, a test rig
is developed specifically to assemble a complete HVAC system exactly as in vehicle level.
All the assembly unit and components such as compressor, condenser, thermal expansion
valve (TXV), evaporator, blower, air conditioner pipe, and related hose is supplied to USM
by PROTON. An electric motor being used to drive the compressor pulley to run the whole
HVAC system.
For measurement of noise and vibration, microphone and accelerometer sensors is
used by locating all of them at related components to be analysed. Test conducted under
two patterns of car in idle and by elevated speed or rpm tracking where tachometer is used
to measure the engine speed. From data collected, analysis is made includes the spectrum
analysis and order analysis. Later, verification is made by noise detection from real time
vibration and noise data using sound diagnosis from LMS Test.Lab software. In addition,
with the aid from sound camera, source of noise at related components and parts can be
located. After determining the source and type of noise such as hissing, humming, clicking,
and rush noise from the HVAC system, a proper justification is made regarding the
generation of noise from related components involved and how they operate. Main
contributors from each type of HVAC noise is identified for design solution and
countermeasure to be proposed in future. This would be taken as refinement initiative to
improve current design guideline for HVAC system in order to come out with HVAC
system exhibits low noise level for a better passenger in cabin comfort and experience.