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C H A P T E R 3
NVH Testing and Analysis of
Hybrid Powertrains
e noise and vibration are attracting more and more attention, and it has become one of the
most important technical indicators of vehicles. Moreover, many countries establish strict rules
to control the vibration and noise of automobiles, and many consumers take the NVH per-
formance as one of the important considerations when choosing a car [49–55]. erefore, it is
necessary to conduct the vibration and noise tests of hybrid vehicles, to identify their main noise
sources and make an objective evaluation of their vibration and noise conditions.
Compared to traditional cars, the full HEV is a complex electromechanical coupling sys-
tem, which produces vibration and noise different from traditional vehicles. In order to solve
the serious noise and vibration problem of the hybrid powertrain, experiments are carried out
and test results are analyzed.
3.1 PREPARE OF EXPERIMENTS
is experiment is based on the above-mentioned compound planetary power-split hybrid sys-
tem developed by Greely Automobile Co., Ltd, which is a power-coupled transmission con-
sisting of an engine and two motors. It uses a two-row planetary gear set, two independent
high-efficiency DC motor, and two lock-up brakes to make the system effective. e vibration
and noise of this system are within the acceptable range of the human body during the hybrid
mode. However, there is a serious NVH issue under the pure electric mode, which directly af-
fects the ride comfort. To solve these problems, it is necessary to carry out tests to figure out the
main noise source and make an objective evaluation of the vibration and noise conditions of the
powertrain.
3.1.1 TEST ENVIRONMENT
e HEV powertrain experimental system is provided in Fig. 3.1, consisting of a 1.6 L ICE, the
CPGS, E1 and E2, Nickel hydrogen battery package, air cooling fan, gasoline supply, analogical
loading AC motors, electric units, and sensors. e experimental system is attached to loading
motors to simulate a vehicle. e engine’s maximum power is 89 kW with a nominal speed of
5500 rpm and a maximum torque of 150 Nm. In addition, the battery utilizes 192 cells with a
nominal voltage of 1.5 V. e battery connects to E1 and E2, permanent magnetic synchronous
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