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Design & Development of Partial Engine Encapsulation for Interior Noise Reduction in Commercial Vehicles

VE Commercial Vehicles Ltd-Sourabh Jadhav
VE Commercial Vehicles Ltd.-Yadhu S. Aswan
  • Technical Paper
  • 2019-01-1589
To be published on 2019-06-05 by SAE International in United States
This paper focuses on partial encapsulation technique for reducing air-borne noise from the rocker cover of a commercial vehicle diesel engine. Due to increasing awareness, customers demand for improvised NVH-Noise Vibration and Harshness performance in modern day vehicles. Better NVH performance implies better comfort for passengers as well as vehicle operator. This further increases the driver up time due to reduced driver fatigue. In order to improve NVH performance of existing vehicle and observe different noise and vibration zones, detailed noise and vibration mapping was carried out on one of our vehicle platform. It is observed that engine noise is one of the major contributors for interior noise, apart from road inputs etc. There are well established methods to reduce the inherent noise of the engine, but the same might affect other performance parameters including fuel efficiency and exhaust emissions, which are pain areas of major automotive industries due to stringent homologation norms. Engine top area partial encapsulation with barrier cover is designed considering various integration as well as heat load constraints at vehicle level.…

Truck front cabin mount tuning for cabin Noise boom elimination and overall interior noise reduction.

VE Commercial Vehicles Ltd-Sourabh Jadhav
VE Commercial Vehicles, Ltd.-Saahil Saxena
  • Technical Paper
  • 2019-01-1513
To be published on 2019-06-05 by SAE International in United States
In today's automobile industry refined NVH performance is a key feature and of high importance governing occupant comfort and overall quality impression of vehicle. This paper interior noise measurement is done on one of the light truck and few dominant low frequency noise booms were observed in operation range. Modal analysis was done for the cabin at virtual as well as experimental level and few modes were found close to these noise booms. Vibrations were measured across the various cabin mounts and it was found that the isolation of front mounts is not effective at lower boom frequencies. Taking this as an input, the mount hardness and profile optimized to shift the natural frequency and hence improve the isolation behavior at the lowest dominant boom frequency. This was followed by static and dynamic measurement of the mounts at test rig level and finally the interior noise measurement after fitment on truck. Boom elimination and overall interior noise reduction is achieved with this approach. This paper takes up a real-time noise scenario , its root cause…

Research on active noise control method on the reduction of drivetrain noise from a heavy off-road vehicle

Dongfeng Motor Technical Center-zuguo xia
Gissing Tech Co Ltd-Wei Huang, Longchen Li, Xiaojun Chen, Xiujie Tian, Keda Zhu, Changwei Zheng, Jiapeng Zhao, Renjie Dai
  • Technical Paper
  • 2019-01-1566
To be published on 2019-06-05 by SAE International in United States
Drivetrain noise from heavy off-road vehicles mainly includes engine noise, drive shaft noise, wheel-side gear noise, tire pattern noise etc. They are the main noise source for such vehicles as they greatly influence the ride comfort of the passengers inside. This paper solved the drivetrain noise problem of a heavy off-road vehicle using the method of active noise control. Firstly, the vehicle is benchmarked and the noise problems are analyzed, while the noise sources are identified by analyzing the transmission principles of the drivetrain; secondly, active noise control strategies are made for the vehicle based on the noise profiles under various operating conditions; thirdly, the multiple parameters for active noise control are computed from simulations modeling the vehicle in idle, constant speed and acceleration respectively; lastly, road tests are conducted using the multiple parameters from the simulations and a noise reduction of 2-4 dB can be achieved in the whole vehicle. The results has shown that active noise control is an effective method for drivetrain noise reduction in heavy off-road vehicles as this paper provides…

Brake squeal noise reduction in city buses

Tata Motors Ltd-Ravi Ranjan
Tata Motors, Ltd.-Harish Kumar Gangwar
  • Technical Paper
  • 2019-01-1572
To be published on 2019-06-05 by SAE International in United States
Buses have become one of the most widely used mode of public transportation, particularly for city applications. Indeed, passenger comfort and vehicle noise are a major concern faced by automotive industry. Brake system is one such contributor to undesired vibrations and obnoxious noise. Squeal noise, caused due to friction-induced vibrations, is a serious customer irritant to the bus passengers as well as the environment, also leading to brake performance deterioration and monetary abominations in terms of warranty costs. Brake squeal noise has been considerably studied for over years. Several design modifications and structural changes have been incorporated to prevent the occurrence of squeal noise, but the issue persists. In this paper, we have discussed on brake squeal noise reduction in city buses by optimisation brake drum diameter, selection of different friction liner linings and optimising other brake components sizes. Keywords: Squeal, brakes, drum, vibration, bus, comfort

Design of innovative noise sealing grommets used in commercial vehicles and their experimental noise sealing performance characterization

VE Commercial Vehicles Ltd-Pushpendra Gehlot
VE Commercial Vehicles, Ltd.-Saahil Saxena
  • Technical Paper
  • 2019-01-1537
To be published on 2019-06-05 by SAE International in United States
In today’s automobile industry refined NVH performance is a key feature and of high importance governing occupant comfort and overall quality impression of vehicle. One of key challenging elements is the effective sealing of noise against direct infiltration from various locations including the gaps and holes of vehicle routing pipes and cables. This paper starts with the design of innovative grommet profiles for noise sealing while not affecting the ease of fitment and manufacturing .Various iterations were carried out to arrive at final grommet designs for both single and dual pipes configurations, and the final designs area discussed in details. This is followed by the characterization of grommet noise sealing behavior with respect to frequency spectrum, in Insertion loss chambers and then comparison of same with original designs .Further, the design of proposed grommets are compared and discussed for noise sealing performance. The paper also investigates the effect of pipe protective cover on the grommet noise sealing performance. Experiments are done both -with and without sealing of the pipe protective cover, and then the grommet…

Structural-Acoustic Modeling & Optimization of a Submarine Pressure Hull

Michigan Engineering Services, LLC-Geng Zhang
University of Michigan-James Spain, Nickolas Vlahopoulos
  • Technical Paper
  • 2019-01-1498
To be published on 2019-06-05 by SAE International in United States
The Energy Finite Element Analysis (EFEA) has been validated in the past through comparison with test data for computing the structural vibration and the radiated noise for Naval systems in the mid to high frequency range [Vlahopoulos, Wu, Medyanik]. A main benefit of the method is that it enables fast computations for full scale models. This capability is exploited by using the EFEA for a submarine pressure hull design optimization study. A generic but representative pressure hull from [Jackson] is considered. Design variables associated with the dimensions of the king frames, the thickness of the pressure hull in the vicinity of the excitation (the latter is considered to be applied on the king frames of the machinery room), the dimensions of the frames, and the damping applied on the hull are adjusted during the optimization process in order to minimize the radiated noise in the frequency range from 1,000Hz to 16,000Hz. Constraints on the total amount of damping that can be used are considered (resource driven constraints) and structural collapse constraints [Myers, et. al, Comstock]…

Driveline NVH integration of A NA truck program

AAM (American Axle & Mfg Inc)-Christopher Folts, Alexander Sandstrom
American Axle & Manufacturing-Ying Peng, Zhaohui Sun, Gregory Kopp, Zhenghong Shi
  • Technical Paper
  • 2019-01-1559
To be published on 2019-06-05 by SAE International in United States
In current automotive industry, it is well known that the driveline subsystem and components are normally from different automotive suppliers for OEMs. In order to ensure proper system integration and successful development of driveline system NVH performances, collaboration efforts between OEMs and suppliers are very demanding and important. In this paper, a process is presented to achieve successfulness in developing and optimizing vehicle integration through effective teamwork between a driveline supplier and a major OEM. The development process includes multiple critical steps. They include target development and roll down, targets being specific and measurable, comprehension of interactions of driveline and vehicle dynamics, accurate definition of sensitivity, proper deployment of modal mapping strategy, which requires open data sharing; and system dynamics and optimization. More specially, the supplier can work with OEM to seek the most cost effective solutions, through tuning the driveline system dynamics to provide “quiet” frequency zone against vehicle sensitivity, to avoid normally needed costly suspension changes. A case study of a pickup vehicle driveline program integration is used in this paper to illustrate…

Comparison of Measurement Methods for Evaluating Displacement of Commercial Vehicle Seats

CVG-James Haylett
Univ of Washington-Peter Johnson
  • Technical Paper
  • 2019-01-1481
To be published on 2019-06-05 by SAE International in United States
Vehicle seats and seat suspension have been evolving ever since the introduction of seats with built-in, integral suspensions. Measuring the relative displacements of the seat suspension may help better understand the magnitude and frequency of displacements the seat suspension and ultimately the occupant is exposed to. These displacement measurements may complement acceleration measurements and may provide additional information to help improve vehicle seat design. Displacement can be measured directly with lasers and potentiometers, but it would be less complicated if accelerometers, already being used to measure and characterize the vehicle and vehicle seat vibration, could be used to measure the displacement. Accelerometers can produce relatively accurate, correlated displacement results from well behaved, controlled, sinusoidal cyclical vibrations, but their utility for measuring real-world random vibration needs further evaluation and characterization. This paper will compare gold-standard methods for measuring vertical seat displacements directly to displacements measured and derived by double integrating the vertical accelerations from accelerometers. Actual field displacement, acceleration and GPS measurements were collected from vehicles as they travelled over different road types. In this paper…

Optimization of Multi-Layer Panel Constructions using Experimental Modeling via Transfer Matrix Method

Bruel & Kjaer North America Inc-John Anton
Bruel & Kjaer North America Inc.-Edward Ray Green
  • Technical Paper
  • 2019-01-1577
To be published on 2019-06-05 by SAE International in United States
In a previous paper, a method was introduced to predict the sound transmission loss (STL) performance of multilayer panel constructions using a measurement-based transfer matrix method. The technique is unique because the characterization of the poro-elastic material is strictly measurement based and does not require modeling the material. In this paper, it is demonstrated how the technique is used to optimize the STL of lightweight, multi-layer panel constructions. Measured properties of several decoupler materials (shoddy and foam) are combined with sheet metal and barrier layers to find optimal combinations. The material properties are measured with the impedance tube per ASTM E2611.

Experiment Studies of Charging Strategy for Lithium-Ion Batteries

Tongji University-Pei Yu, Haifeng Dai, Xuezhe Wei
  • Technical Paper
  • 2019-01-0792
To be published on 2019-04-02 by SAE International in United States
Regarding the lithium-ion batteries used in the electric vehicle, charging time and charging efficiency are the concern of the public. In this paper, a lot of experiments were conducted to investigate the common charging strategies, including the CC-CV (constant current-constant voltage) charging and the pulse current charging, for the LiFePO4 batteries, which are still widely used in commercial vehicles. Charging temperature and the charging current in the CC phase are the main influence factors to be studied for the CC-CV charging strategy, and the contribution of the CC phase and CV phase to the whole charging is analyzed from three aspects, including the time percent, charging energy efficiency and the capacity of battery at different temperatures and charging current. Regarding the pulse charging strategy, the pulse frequency is determined from the perspective of energy loss, then the experiments for pulse charging with different pulse mode, different duty cycle, as well as different charging temperature and charging current were conducted to study the characteristic of pulse charging. In order to eliminate the battery polarization, we optimized…
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