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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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Gear Shift Pattern Optimization for Best Fuel Economy, Performance and Emissions

Chidhanand S.
Mahindra & Mahindra, Ltd.-Lemuel Paulraj, Saravanan Muthiah
  • Technical Paper
  • 2020-01-1280
To be published on 2020-04-14 by SAE International in United States
As the FTP-75 drive cycle does not have a prescribed gear shift pattern, automotive OEMs have the flexibility to design. Conventionally, gear shift pattern was formulated based on trial and error method, typically with 10 to 12 iterations on chassis dynamometer. It was a time consuming (i.e. ~ 3 to 4 months) and expensive process. This approach led to declaring poor fuel economy (FE). A simulation procedure was required to generate a gear shift pattern that gives optimal trade-off amongst conflicting objectives (FE, performance and emissions). As a result, a simulation tool was developed in MATLAB to generate an optimum gear shift pattern. Three different SUV/UV models were used as test vehicles in this study. Chassis dyno testing was conducted, and data was collected using the base and optimized gear shift patterns. Dyno test results with optimized gear shift pattern showed FE improvement of ~ 4 to 5% while retaining the NOx margin well above engineering targets. This labeling FE improvement method did not require any hardware or software changes, thus, involved no additional expense.…
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Rolling Element Bearings - Advanced Modeling for Multibody Simulations

Ghent University - Soete-Dieter Fauconnier
Siemens DI Software NV-Pavel Jiranek
  • Technical Paper
  • 2020-01-0508
To be published on 2020-04-14 by SAE International in United States
The electrification of vehicles, together with the ever-increasing need for more lightweight and durable designs, is putting the NVH performances of the transmission in the spotlight since the generated noises are not masked by the internal combustion engine. To correctly estimate the performances of the transmission while still in the design-phase, predictive models for the main components of the gearbox are of paramount importance. This paper focuses on the modeling of rolling element bearings, a key component that is responsible of transmitting the vibrations from the gear pairs to the surrounding structure while introducing additional excitation frequencies. The modeling techniques use the relative displacement of the rings to compute the corresponding reaction forces by calculating the equilibrium of each rolling element. To do so, the interaction between the rolling elements and the raceways can be modeled employing two different contact models depending on the level of accuracy required. The contact models are, respectively, a Hertz-Based approach that allows for fast computations, and an EHL (Elasto-Hydrodynamic Lubricated) contact model which accounts for the effects of lubrication.…
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Study of the Effective Backlight Angle Influence on Vehicle Aerodynamics and Contamination

General Motors LLC-Danilo Oliveira
University of Campinas-Rogerio Goncalves dos Santos
  • Technical Paper
  • 2020-01-0691
To be published on 2020-04-14 by SAE International in United States
This paper presents contamination simulation results of a 2004 Chevrolet Malibu Maxx with different morphed rear declination angles geometry to understand that effect on the vehicle contamination. Computational fluid dynamics highly-resolved time accurate simulations were performed using a commercial Lattice-Boltzmann solver, to compare the rear end contamination with five different rear declination angles. Aerodynamics simulations were also performed and presented good correlation with theoretical data. The contamination results were compared with aerodynamics simulation results in order to find a trend between the two areas for different declination angles.
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Real-Time Embedded Models for Simulation and Control of Clean and Fuel-Efficient Heavy-Duty Diesel Engines

Daimler Trucks North America-Marc Allain, Siddharth Mahesh
University of Michigan-Saravanan Duraiarasan, Rasoul Salehi, Fucong Wang, Anna Stefanopoulou
  • Technical Paper
  • 2020-01-0257
To be published on 2020-04-14 by SAE International in United States
The ever increasing demand for fuel economy and stringent emission norms drives researchers to continuously innovate and improve engine modes to implement adaptive algorithms, where the engine states are continuously monitored and the control variables are manipulated to operate the engine at the most efficient regime. This paper presents a virtual engine developed by modeling a modern diesel engine and aftertreatment which can be used in real-time on a control unit to predict critical diesel engine variables such as fuel consumption and feed gas conditions including emissions, flow and temperature. A physics-based approach is followed in order to capture vital transient airpath and emission dynamics encountered during real driving condition. A minimal realization of the airpath model is coupled with a cycle averaged NOx emissions predictor to estimate transient feed gas NOx during steady state and transient conditions. The complete airpath and NOx emission model was implemented on a rapid prototyping controller and experimentally validated over steady state and transient emission cycles. The overall performance of the reduced order model was comparable to that of…
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Bearing Fault Diagnosis of the gearbox using blind source separation

Nanjing University of Science & Technology-Hong Zhong, Jingxing Liu, Liangmo Wang, Yang Ding, Yahui Qian
  • Technical Paper
  • 2020-01-0436
To be published on 2020-04-14 by SAE International in United States
Gearbox fault diagnosis is one of the core research areas in the field of rotating machinery condition monitoring. The signal processing-based bearing fault diagnosis in the gearbox is considered as challenging as the vibration signals collected from acceleration transducers are, in general, a mixture of signals originating from an unknown number of sources, i.e. an underdetermined blind source separation (UBSS) problem. In this study, an effective UBSS-based algorithm solution, that combines empirical mode decomposition (EMD) and kernel independent component analysis (KICA) method, is proposed to address the technical challenge. Firstly, the nonlinear mixture signals are decomposed into a set of intrinsic mode function components (IMFs) by the EMD method, which can be combined with the original observed signals to reconstruct new observed signals. Thus, the original problem can be effectively transformed into an over-determined BSS problem. Then, the whitening process is carried out to convert the over-determined BSS into determined BSS, which can be solved by the KICA method. Finally, the ant lion optimization (ALO) is adopted to further enhance the performance of the EMD-KICA…
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MIMO Control of a Turbogenerator for Energy Recovery

Loughborough Univ.-Simon Petrovich, Kambiz Ebrahimi, Nikolaos Kalantzis, Antonios Pezouvanis
  • Technical Paper
  • 2020-01-0261
To be published on 2020-04-14 by SAE International in United States
Market trends for increased engine power and more electrical energy on the powergrid (3kW+), along University of Loughborough for fuel consumption improvements and emissions reduction, are driving requirements for component electrification, including turbochargers. GTDI engines waste significant exhaust enthalpy; even at moderate loads the WG (Wastegate) starts to open to regulate the turbine power. This action is required to reduce EBP (Exhaust Back Pressure). Another factor is catalyst protection, where the emissions device is placed downstream turbine. Lambda enrichment or overfuelling is used to perform this. However, the turbine has a temperature drop across it when used for energy recovery. Since catalyst performance is critical for emissions, the only reasonable location for an additional device is downstream of it. This is a challenge for any additional energy recovery, but a smaller turbine is a design requirement, optimised to operate at lower pressure ratios. A WAVE model of the 2.0L GTDI engine was adapted to include a TG (Turbogenerator) and TBV (Turbine Bypass Valve) with the TG in a mechanical turbocompounding configuration, calibrated with steady state…
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Hybrid Powertrain Choices for Emerging Engine Technologies

Aramco Research Center-Vincent Costanzo
Argonne National Laboratory-Ram Vijayagopal, Daniela Nieto Prada
  • Technical Paper
  • 2020-01-0440
To be published on 2020-04-14 by SAE International in United States
US department of energy estimates the peak efficiency of a modern spark ignited naturally aspirated Otto cycle engine to be 36%. Atkinson cycle engines are estimated to get 40% peak efficiency. Most engines can achieve this peak efficiency only for a limited operating region. Hybrid powertrains enable engine to operate in this efficiently. Overall efficiency is improved by shutting down engine during idle events and by adjusting the operating speed and load on the engine using electric machines. The choice of the powertrain and component sizes depends on the engine characteristics, drive cycles and vehicle technical requirements. This study examines what type of powertrains will be suitable for more efficient engines that are likely to be available in the near future. Some of these technologies achieve higher efficiency with a trade off on power or by accepting a more restrictive operating region. An appropriate powertrain choice can still enable such an engine to be a viable option for an automobile. Using simulation tools, 14 different engine technologies are evaluated in this paper for their fuel…
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Acoustic characteristics prediction and optimization of wheel resonators with arbitrary section

SAIC Motor Corporation Limited-Yimin Sun, Junlei Mao
Tongji University-Rong Guo, Tiantian Mi
  • Technical Paper
  • 2020-01-0917
To be published on 2020-04-14 by SAE International in United States
Tire cavity noise of pure electric vehicles is particularly prominent due to the absence of engine noise, which are usually eliminated by adding Helmholtz resonators with arbitrary transversal section to the wheel rims. This paper provides theoretical basis for accurately predicting and effectively improving acoustic performance of wheel resonators. A hybrid finite element method is developed to extract the transversal wavenumbers and eigenvectors, and the mode-matching scheme is employed to determine the transmission loss of the Helmholtz resonator. Based on the accuracy validation of this method, the matching design of the wheel resonators and the optimization method of tire cavity noise are studied. The identification method of the tire cavity resonance frequency is developed through the acoustic modal simulation and test. A scientific transmission loss target curve and fitness function are defined according to the noise characteristics. Combing the transmission loss prediction theory and particle swarm algorithm, the structure parameters of the wheel resonator are optimized. A remarkable attenuation of tire cavity resonance can be observed through test results.
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Numerical Modeling of Spray Formation under Flash-boiling Conditions

ANSYS Inc-Mingyuan Tao, Long Liang, Yue Wang, Ellen Meeks
  • Technical Paper
  • 2020-01-0328
To be published on 2020-04-14 by SAE International in United States
Flash boiling occurs in sprays when the ambient gas pressure is lower than the saturation pressure of the injected fuel. In the present work, a numerical study was conducted to investigate solid-cone spray behaviors under various flash-boiling conditions. A new spray cone angle correlation that is a function of injection parameters was developed and used for spray initialization at the nozzle exit to capture plume interactions and the global spray shape. The spray-breakup regime control was adjusted to enable catastrophic droplet breakup, characterized by Rayleigh-Taylor (RT) breakup, near the nozzle exit. The model was validated against experimental spray data from five different injectors, including both multi-hole and single-hole injectors, with injection pressure varying from 100 to 200 bar. Different fuels, including iso-octane, n-heptane, n-pentane, ethanol, and n-butanol, were investigated under a wide range of flash-boiling conditions, in which flash boiling was induced by high injected fuel temperature, ranging from 323 to 493 K, and/or low ambient gas pressure, ranging from 0.1 bar to atmospheric. It is found that flash boiling can significantly increase the spray…