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A Case Study on Reducing the Fuel Pulse Noise from Gasoline Engine Injectors

FCA US LLC-Weiguo Zhang, Toon Tan, John Malicki, Glenn Whitehead
  • Technical Paper
  • 2020-01-1276
To be published on 2020-04-14 by SAE International in United States
Vehicle NVH performance is a very important consideration for vehicle buyers in the marketplace. There are many noise sources from the fuel system to generate noise in a vehicle. Among them, the pressure pulsations due to the rapid opening and closing of gasoline engine injectors can cause undesirable fuel pulse noise inside the vehicle cabin. As the pressure pulsation propagates in the fuel supply line toward to rear end of the vehicle, the pressure energy is transferred from fuel lines to the vehicle underbody through clips and into the passenger compartment. It is crucial to attenuate the pressure pulsation inside the fuel line to reduce the fuel pulse noise. In this paper, a case study on developing an effective countermeasure to reduce the objectionable fuel pulse noise of a V8 gasoline injection system is presented. First, the initial interior noise of a prototype vehicle was tested and the objectionable fuel pulse noise was exhibited. The problem frequency ranges with pulse and ticking noise content were identified. Several test iterations on root causing analysis and countermeasures…
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A Holistic Approach to Develop a Modern High Power Density Diesel Engine to Meet Best-in-class NVH levels.

Mahindra & Mahindra, Ltd.-Vikraman Vellandi, Prasad Namani, Rajkumar Bhagate, Madhu Chalumuru
  • Technical Paper
  • 2020-01-0406
To be published on 2020-04-14 by SAE International in United States
The ever-increasing customer expectations put a lot of pressure on car manufacturers to constantly reduce the noise, vibration and harshness (NVH) levels. This papers presents the holistic approach used to achieve best-in-class NVH levels in a modern high-power density 1.5 lit 4 cylinder diesel engine. The base engine architecture was designed with NVH reduction features such as crank-offset, cast iron crankcase, stiffened ladder frame, structural oil pan and front cover. Piston skirt profile was optimized to reduce the slapping noise by carefully studying the secondary motion and skirt contact pressure. The plastic parts such as cylinder head cover and intake manifold were designed with closely spaced ribs and high wall thickness. Natural frequency targets for different parts were set for the entire engine at component level and system level and confirmed through simulations. High frequency acoustic simulation was carried out to identify and improve the areas of high surface velocity. "Acoustic holography" technology was extensively used to identify the areas of high noise radiation in the running engine. Based on the measurements, it was identified…
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Driveline Torque Profiling Based on Speed Estimation for xEVs

Hyundai Motor Group-Jiwon Oh, Jeong Soo Eo, Sung Jae Kim, Dohee Kim
  • Technical Paper
  • 2020-01-0964
To be published on 2020-04-14 by SAE International in United States
This paper suggests a method to formulate the driveline torque command for vehicles that use electric motor as part of their sources for providing driving power. The shape of the driveline torque profile notably influences the drivability criteria of the vehicle, and among them, driveline NVH and responsiveness are often tradeoffs for each other. Hence the real-time computed driveline torque profiling (DTP) enables formulation of the effective torque command at any given time to simultaneously satisfy both NVH and responsiveness criteria. Such task is fulfilled by using a shaft distortion prediction model based on a motor speed observer. A compensation torque command based on the amount of shaft distortion is formulated to prevent the shaft distortion with minimum effort. The effectiveness of the suggested driveline torque profiling method is verified using an actual vehicle, and the vehicle NVH and responsiveness are numerically assessed for comparison.
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A Research on Multi-disciplinary Optimization of the Vehicle Hood at Early Design Phase

Changan Automobile Co., Ltd.-Ruyi Chen
Chongqing University-Huijie Xu, Yue Fu, Guan Lin, Zhenfei Zhan
  • Technical Paper
  • 2020-01-0625
To be published on 2020-04-14 by SAE International in United States
Vehicle hood design is a typical multi-disciplinary task. It has to meet the demands of different attributes like safety, dynamics, statics, NVH (Noise, Vibration, Harshness). Multi-disciplinary optimization (MDO) of vehicle hood at conceptual design phase is an efficient way to support right design decision and avoid late-phase design changes. However, due to lacking of CAD models, it is difficult to realize MDO at conceptual design phase. In this research, a new method of design and optimization at conceptual design phase is proposed to improve the design efficiency. Firstly, a parametric concept hood model is first built to optimize the structure size, shape and topography. Secondly, an integration automatic platform is developed to integrate CAD/CAE software to call simulation queen, undertake sensitivity analysis and find optimum result. Besides, a multi-disciplinary design example of vehicle hood is given as a test of the proposed methodology in details. The results show that this method reduce weight by 10.1%, improve pedestrian protection performance score from 7.35 to 7.65 according to the China New Car Assessment Program(C-NCAP).
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Efficient Surrogate-based NVH Optimization of a Full Vehicle Using FRF Based Substructuring

Beta CAE Systems USA Inc.-Inseok Park
Oakland University-Dimitrios Papadimitriou
  • Technical Paper
  • 2020-01-0629
To be published on 2020-04-14 by SAE International in United States
The computer simulation with the Finite Element (FE) code for the structural dynamics becomes more attractive in the industry since it enables quickly evaluating the dynamic performances of the mechanical products like automobile in development with improved accuracy owing to modern technological advancements. However, it normally takes a prohibitive amount of computation time when design optimization is performed with conducting a dynamic analysis using a large-scale FE model many times. Exploiting Dynamic Structuring (DS) leads to alleviating the computational complexity since DS necessities iterative reanalysis of only the substructure(s) to be optimally designed. In this research, FRF Based Substructuring (FBS) is implemented to realize the benefits of DS for fast single- and multi-objective evolutionary design optimization. Also, Differential Evolution (DE) is first combined with two sorting approaches of NSGA-II and Infeasibility Driven Evolutionary Algorithm (IDEA) for effective constrained single- and multi-objective evolutionary optimization. The effectiveness of the proposed algorithm (NSGA-II/DE-IDEA) is verified using several test functions for constrained single- and multi-objective optimization. To circumvent the need for frequent time-consuming simulation runs, Kriging surrogate models are…
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New Integrated Electromagnetic and NVH Analyses of Induction Traction Motors for Hybrid and Electric Vehicle Applications

General Motors LLC-Song He, Jingchuan Li, Michael Muir, Gautam GSJ, Bhyri Rajeswara Rao
  • Technical Paper
  • 2020-01-0413
To be published on 2020-04-14 by SAE International in United States
Electric motor whine is one of the main noise sources of hybrid and electric vehicles. Compared with permanent magnetic motors, characterization and prediction of traction induction motor is particularly challenging due to high computational costs to calculate the electro-magnetic (EM) forces as noise source, as well as motor slip and harmonic orders change at different torque/speed operating conditions. Historically, induction motor NVH is designed qualitatively by optimizing motor topology including rotor bar, pole number and slot counts etc. A new integrated electromagnetic and NVH analysis method is developed and successfully validated at all dominant motor orders for an automotive traction motor, which enables quantitative prediction of induction motor N&V performance in early design stage: First, a new Equivalent Rotor Current Method (ERCM) is proposed that significantly reduces the computational time required to calculate the EM force over transient response. Dominant force orders are compared with conventional EM finite-element (FE) results and the new ERCM method shows good correlation. Next, a High-Fidelity (Hi-Fi) mechanical FE model is developed for the induction motor stator, with less than…
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A Study on the Development of the CPA (Centrifugal Pendulum Absorber)Reducing the Rattle & Booming Noise in the Manual Transmission Vehicle

Ukjin Kim
  • Technical Paper
  • 2020-01-0397
To be published on 2020-04-14 by SAE International in United States
In recent years, the automotive engine strategies are forced on downsizing and down speeding to enhance fuel economy and reduce the emission. These make torque increase significantly in order to improve the vehicle performance, especially in diesel engines. At this time, the torsional damper performs the most important role in the driveline NVH of the manual transmission system. The clutch disk with torsional dampers is not easy to be applicable to the high torque of low speed RPM range. And DMF with sufficient isolation of vibrations of driving system includes disadvantages of the expensive cost, delayed response, and engine NVH aspect deteriorated due to increase of angular acceleration of engine. This paper presents that the Centrifugal Pendulum Absorber (CPA) is applied to maximize the isolation and to compensate for the disadvantages of DMF and SMF system. Furthermore, CPA was developed for the first time in the world on SMF clutch discs in manual transmission.
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Engine Mount Stopper Design Techniques to Balance Vehicle Level Buzz, Squeak, Rattle and Durability.

Tata Motors, Ltd.-Sandip Hazra, Sagar Deshmukh
  • Technical Paper
  • 2020-01-0401
To be published on 2020-04-14 by SAE International in United States
In the highly competitive global automotive market and with the taste of customer becoming more refined, the need to develop high quality products and achieve product excellence in all areas to obtain market leadership is critical. Buzz, squeak and rattle (BSR) is the automotive industry term for the audible engineering challenges faced by all vehicle and component engineers. Minimizing BSR is of paramount importance when designing vehicle components and whole vehicle assemblies. Focus on BSR issues for an automobile interior component design have rapidly increased due to customer's expectation for high quality vehicles. Also, due to advances in the reduction of vehicle interior and exterior noise, engine mounts have recently been brought to the forefront to meet the vehicle interior sound level targets. Engine mounts serve two principal functions in a vehicle, vibration isolation and engine support. The objective of this paper to experimentally analyze the impact of conventional engine mount design on the rattle and whistling noise audible from the engine mounts when the vehicle is subjected to rough road conditions and pot holes…
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Enhanced Windshield NVH Modeling for Interior Cabin Noise

FCA US LLC-Ahmad Abbas, Wael Elwali, Aravindhan Thirukonda, Syed Haider, Francisco Sturla
  • Technical Paper
  • 2020-01-1100
To be published on 2020-04-14 by SAE International in United States
The windshield is an important component in vehicle NVH performance. It plays an integral role in affecting the interior cabin noise. The windshield acts as a large panel typically oriented near vertical at the front of vehicle’s acoustic cavity, hence modeling it appropriately is key to have a reliable prediction of cabin interior noise. The challenge of modeling the windshield accurately rises from the structural composition of different types of windshields. For automotive applications, windshield come in several structural compositions today. In this paper, we will discuss two types of windshield glass. First is a typical laminated glass with polyvinyl butyral (PVB) layer and second is a typical acoustic glass with PVB and vinyl layers. Acoustic glass improves acoustics characteristics of the glass in frequencies of ~ 1200 Hz to ~4000 Hz range. Low frequency interior cabin noise studied with FEA is typically below 500 Hz. The acoustic glass doesn’t provide any benefits in this range and in many cases we see an adverse contribution at lower frequencies since the acoustic windshield tend to be…
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Development of Commercial Vehicle E-Axle System Based on NVH Performance Optimization

Jiangxi Jiangling Chassis Co., Ltd.-Yong Xu
  • Technical Paper
  • 2020-01-1421
To be published on 2020-04-14 by SAE International in United States
With the continuous development of various technologies in the field of electric vehicles, more and more mature products are put into the market. Among them, electric commercial vehicle has been supported by many preferential policies because of its wide use and high energy utilization and has developed rapidly in recent years. At present, the electric drive-train systems of commercial vehicles can be divided into motor direct drive, integrated el-axle and distributed e-wheel drive. The first type only uses motor to replace the engine, and the other parts have little change. This method has low transmission efficiency and loose structure, which is a temporary transition scheme. The drive types of integrated e-axle and distributed e-wheel have their own advantages and disadvantages, which way to become the mainstream of the future has not yet been decided. This research is based on the development of an electric commercial vehicle integrated e-axle system, in which the NVH performance is the most important consideration index. Firstly, the systematic engineering analysis is carried out according to the vehicle parameters. After determining…