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A New Co-Simulation Approach for Tolerance Analysis on Vehicle Propulsion Subsystem

Gamma Technologies LLC-Iakovos Papadimitriou
GM Global Propulsion Systems-Claudio Mancuso, Domenico Cavaiuolo, Giuseppe Corbo
Published 2019-09-09 by SAE International in United States
An increasing demand for reducing cost and time effort of the design process via improved CAE (Computer-Aided Engineer) tools and methods has characterized the automotive industry over the past two decades. One of the main challenges involves the effective simulation of a vehicle’s propulsion system dealing with different physical domains: several examples have been proposed in the literature mainly based on co-simulation approach which involves a specific tool for each propulsion system part modeling. Nevertheless, these solutions are not fully suitable and effective to perform statistical analysis including all physical parameters. In this respect, this paper presents the definition and implementation of a new simulation methodology applied to a propulsion subsystem. The reported approach is based on the usage of Synopsys SABER as dominant tool for co-simulation: models of electronic circuitry, electro-mechanical components and control algorithm are implemented in SABER to perform tolerance analysis; in addition, a dynamic link with engine plant model developed in GT-SUITE environment has been established via a dedicated procedure. Moreover, a HPC Grid (High Performance Computing Grid) is used with…
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Integrated Multi-Physics Simulation for Full-Vehicle Low Frequency NVH Optimization in HEVs

Gamma Technologies LLC-Llorenc Foraste Gomez, Jonathan Zeman
Ford Motor Company-Jack Liu
Published 2019-06-05 by SAE International in United States
The recent automotive industry trend towards electrification has created new challenges for NVH engineers. These challenges stem from new powertrain architectures and their complex interactions, the governing control strategies which aim to optimize energy management, and new unmasked sources of excitation. Additionally, vehicle manufacturers are attempting to reduce hardware testing in order to rapidly satisfy increasing production demand and to minimize its costs. Hence, to meet the above-mentioned challenges up front in the development process of Hybrid Electrical Vehicles (HEVs) while balancing competing design objectives of drivability, durability and NVH, a simulation-led design and optimization is required.NVH problems are often the result of mechanisms that originate through complex interactions between different physical domains (flow, electromagnetic, structural/mechanical, control logic, etc.) and the assembly of individual components into a complete system. Therefore, accurate system-level integrated models are becoming a requirement to solve modern NVH problems.Combining the optimal balance between simulation and experimental data, this article describes a joint effort between Ford and Gamma Technologies to develop a general methodology to perform full-vehicle low frequency NVH analysis. Using…
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Modeling Fuel Tank Draining/Sloshing in a Typical Transiently Accelerating Vehicle using GT-SUITE for Reliable Tank Designing

Gamma Technologies LLC-Arpit Tiwari, Nils-Henning Framke
Published 2019-04-02 by SAE International in United States
Draining and fuel starvation prediction is of critical importance in designing and approving fuel tanks. Simulation of fluid dynamics to predict draining of a moving tank having multiple fuel compartments and multiple ports is, however, challenging. This is because the dynamics involve multiple fluids which follow distinct thermodynamics - compressible air at the top and nearly incompressible fuel below it. Moreover, for a typical vehicle accelerating transiently in a general trajectory (road profile), the surface angle keeps changing which leads to dynamic fuel covering/uncovering of interior as well as outlet ports. Simulation of these effects often requires 3D multiphase solution, which is computationally expensive especially when it is required to model additional fluid systems such as fuel pipes and jet pumps. We present fast and efficient modeling and simulation of tank draining using the 0D/1D framework of GT-SUITE. The flexibility and robustness of the inbuilt flow solver allows accurate solution of the associated multiphase flow dynamics. Furthermore, the software is geometrically flexible to capture the surface angle variations (sloshing) inside complicated 3D shaped tanks in…
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A Quasi-Steady Diffusion-Based Model for Design and Analysis of Fuel Tank Evaporative Emissions

Gamma Technologies LLC-Emad Ghadirian, Jonathan Brown, Syed Wahiduzzaman
Published 2019-04-02 by SAE International in United States
In this paper, a fuel tank evaporation/condensation model was developed, which was suitable for calculation of evaporative emissions in a fuel tank. The model uses a diffusion-controlled mass transfer approach in the form of Fick's second law in order to calculate the average concentration of fuel vapor above the liquid level and its corresponding evaporation rate. The partial differential equation of transient species diffusion was solved using a separation of variables technique with the appropriate boundary conditions for a fuel tank. In order to simplify the solution, a quasi-steady assumption was utilized and justified. The fuel vapor pressure was modeled based on an American Petroleum Institute (API) procedure using either a distillation curve or a Reid Vapor Pressure (RVP) as an experimental input for the specific fuel used in the system. The advantage of this model compared to other published models is the fact that it is a non-equilibrium model that considers the effects of mass transfer between phases. The model was validated with transient data for both short (drive cycle) and long (diurnal cycle)…
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Development and Calibration of One Dimensional Engine Model for Hardware-In-The-Loop Applications

Gamma Technologies LLC-Daniel Schimmel
Chalmers University of Technology-Jelena Andric, Jonas Sjoblom
Published 2018-04-03 by SAE International in United States
The present paper aims at developing an innovative procedure to create a one-dimensional (1D) real-time capable simulation model for a heavy-duty diesel engine. The novelty of this approach is the use of the top-level engine configuration, test cell measurement data, and manufacturer maps as opposite to common practice of utilizing a detailed 1D engine model. The objective is to facilitate effective model adjustments and hence further increase the application of Hardware-in-the-Loop (HiL) simulations in powertrain development. This work describes the development of Fast Running Model (FRM) in GT-SUITE simulation software. The cylinder and gas-path modeling and calibration are described in detail. The results for engine performance and exhaust emissions produced satisfactory agreement with both steady-state and transient experimental data. Therefore, the presented methodology shows a great potential for testing and validation of new control strategies in Engine Management System (EMS) and for optimizing engine performance using HiL systems. The model has been successfully used in powertrain testing and calibration in the VIRtual TEst Cell (VIRTEC) system at Volvo Penta.
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CAE Method for linking electrochemical Lithium-ion models into integrated system-level models of electrified vehicles

Gamma Technologies LLC-Joe Wimmer, Iakovos Papadimitriou
EC Power Inc.-Gang Luo
Published 2018-04-03 by SAE International in United States
Historically, electrical-equivalent modeling of battery systems has been the preferred approach of engineers when modeling hybrid and electric vehicles at the system level. This approach has provided modeling engineers good boundary conditions for batteries, with accurate terminal voltage and state of charge (SOC) calculations; however, it fails to provide insight into the electrochemical processes taking place in their Lithium-ion cells, necessary to optimize control algorithms and predict aging mechanisms within the battery. In addition, the use of predictive battery models that simulate electrochemical mechanisms empowers engineers with the ability to predict the performance of a Lithium-ion cell without requiring cells to be manufactured. If hardware is already available and tested, the use of physics-based battery models allows the simulation of the cell to be done well beyond the conditions at which the battery has been tested. Thus battery testing and characterization effort is reduced significantly without compromising results accuracy. This paper proposes a method of linking electrochemical Lithium-ion models of battery systems with multi-domain (electrical, mechanical, thermal, and flow domains) system-level models of hybrid and…
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Development of a K-k- Phenomenological Model to Predict In-Cylinder Turbulence

SAE International Journal of Engines

Gamma Technologies LLC-Navin Fogla, Michael Bybee, Syed Wahiduzzaman
Politecnico di Torino-Mohsen Mirzaeian, Federico Millo
  • Journal Article
  • 2017-01-0542
Published 2017-03-28 by SAE International in United States
The turbulent flow field inside the cylinder plays a major role in spark ignition (SI) engines. Multiple phenomena that occur during the high pressure part of the engine cycle, such as early flame kernel development, flame propagation and gas-to-wall heat transfer, are influenced by in-cylinder turbulence. Turbulence inside the cylinder is primarily generated via high shear flows that occur during the intake process, via high velocity injection sprays and by the destruction of macro-scale motions produced by tumbling and/or swirling structures close to top dead center (TDC) . Understanding such complex flow phenomena typically requires detailed 3D-CFD simulations. Such calculations are computationally very expensive and are typically carried out for a limited number of operating conditions. On the other hand, quasi-dimensional simulations, which provide a limited description of the in-cylinder processes, are computationally inexpensive. They require only a small fraction of the computational resources needed for CFD calculations and can be carried out for a large number of cases. Such simulations typically use zero dimensional (0D) phenomenological sub-models to simulate the various in-cylinder phenomena such…
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