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Technical Paper

Foaming Visualization of Thermoplastic Polyolefin (TPO) Blends with N2

2007-04-16
2007-01-0572
Polymers are often blended to create compounds with new or enhanced properties in order to compensate for an individual polymer's weakness or lack of inherent properties. In the field of polymer foaming, polymer blends are also used to generate fine-cell structures via heterogeneous nucleation. Recently, an interest in physical blowing agents, such CO2 and N2, has increased because of their low impact on the environment. It has thus become additionally important to pursue research on the foaming of polymer blends employing these particular physical blowing agents in an effort to keep up with the demand for environmentally friendly products. In this study, thermoplastic polyolefin (TPO) blends were prepared with polypropylene (PP) and a metallocene-based polyolefin elastomer (POE) using twin-screw extruders and a batch mixer.
Technical Paper

Improving Flow Uniformity in a Diesel Particulate Filter System

2001-05-07
2001-01-1944
In this study, a simulation-based flow optimization of the diesel particulate filter (DPF) system is performed. The geometry and the swirl component of the inlet flow is optimized to improve flow uniformity upstream of the filter and to decrease overall pressure drop. The flow through the system is simulated with Fluent computational fluid dynamics (CFD) software from Fluent Inc. The wall-flow filter is modeled with an equivalent porous material. This study only investigates the clean flow. The DPF system is composed of three parts: the inlet diffuser, the filter and the outlet nozzle. In the original system a linear cone joins the inlet and outlet pipes to the cylindrical filter. Due to the large opening angle of this cone, flow separates and creates a recirculation zone between the inlet and the filter. The flow pattern reveals that a large area of the filter is not used: More than 88% of the air flow passes through less that 53% of the area.
Technical Paper

The Influence of the Bauschinger Effect on Springback Prediction for Dual Phase Steel

2006-04-03
2006-01-0145
Springback is one of the main concerns in sheet metal forming with the increased use of advanced high strength steels, among which dual phase steels are gaining popularity. Although finite element analysis (FEA) has been successfully used in simulating complicated forming processes, it is difficult to accurately predict springback due to certain complex material behaviors such as the non-linear recovery behavior. In this study, the tension-unloading-reloading (TUR) test and XRD analysis have been employed to investigate non-linear recovery through Bauschinger Effect (BE) measurement at different pre-strain levels. The results demonstrated that dual phase steels exhibited the strong BE. The FEA simulation of springback prediction in the deep-draw bending test showed that the simulation accuracy was significantly improved by incorporating the Bauschinger effect.
Technical Paper

Model Identification and Analysis of a High Performance Hydrostatic Actuation System

2000-09-11
2000-01-2619
A hydrostatic actuation system referred to as the Electro Hydraulic Actuator (EHA) has been designed and prototyped. In this paper, a mathematical model of the EHA is reviewed and analyzed. This theoretical analysis is supported by open-loop experimental results that indicate the presence of nonlinearities but at a degree that is considerably less than that of conventional hydraulic systems with servo-valves. The behavior of the system can be approximated as piece-wise linear with the damping ratio and natural frequency changing according to a piece-wise operating region. The EHA model is used in conjunction with experimentation and numerical optimization for quantifying the influence of unknown parameters in this system. A parametric model for the EHA is subsequently proposed and validated.
Technical Paper

Injection Molded Hybrid Natural Fibre - Thermoplastic Composites for Automotive Interior Parts

2004-03-08
2004-01-0014
Eco-efficient and cost effective natural fibre - thermoplastic composites have gained attention to a great extent in the automotive industry. Most of the OEM specifications for automotive interior parts, for example, instrument panels, recommend the composite should have a minimum flexural modulus of 1900 MPa, a notched Impact strength greater than 150 J/m at room temperature and a melt flow index of 5 g/10min and above [1, 2 and 3]. The objective of this work was to develop a high performance hybrid composite by injection molding process of the composites made from natural fibre in combination with glass fibre or calcium carbonate in a thermoplastic matrix to meet the specifications required for automotive interior parts applications. Mechanical properties, such as tensile and flexural strengths and moduli of the composites prepared, were found to be highly promising.
Technical Paper

Concurrent Quantitative Laser-Induced Incandescence and SMPS Measurements of EGR Effects on Particulate Emissions from a TDI Diesel Engine

2002-10-21
2002-01-2715
A comparison of scanning mobility particle sizer (SMPS) and laser-induced incandescence (LII) measurements of diesel particulate matter (PM) was performed. The results reveal the significance of the aggregate nature of diesel PM on interpretation of size and volume fraction measurements obtained with an SMPS, and the accuracy of primary particle size measurements by LII. Volume fraction calculations based on the mobility diameter measured by the SMPS substantially over-predict the space-filling volume fraction of the PM. Correction algorithms for the SMPS measurements, to account for the fractal nature of the aggregate morphology, result in a substantial reduction in the reported volume. The behavior of the particulate volume fraction, mean and standard deviation of the mobility diameter, and primary particle size are studied as a function of the EGR for a range of steady-state engine speeds and loads for a turbocharged direct-injection diesel engine.
Technical Paper

The Effects of Nano-clay on Extrusion Microcellular Foaming of Nylon

2005-04-11
2005-01-1670
This paper demonstrates the effects of nano-clay on the microcellular foam processing of nylon. First, Nylon 6 nanocomposites with 1 wt% clay were prepared by a twin screw extruder. The nanocomposite structures were characterized by XRD and TEM. Nylon and its nanocomposites were foamed in extrusion using CO2. The cell morphologies of nylon and its nanocomposite foams were investigated. It appeared that the nano-clay not only enhanced cell nucleation, but also suppressed cell deterioration in the microcellular foaming of nylon.
Technical Paper

Effect of CO2 Content on Foaming Behavior of Recyclable High-Melt-Strength PP

2006-04-03
2006-01-0336
This paper presents an experimental study on the foaming behavior of recyclable high-melt-strength (HMS) branched polypropylene (PP) with CO2 as a blowing agent. The foamability of branched HMS PP has been evaluated using a tandem foaming extruder system. The effects of CO2 and nucleating agent contents on the final foam morphology have been thoroughly investigated. The low density (i.e., 12~14 fold), fine-celled (i.e., 107–109 cells/cm3) PP foams were successfully produced using a small amount of talc (i.e., 0.8 wt%) and 5 wt% CO2.
Technical Paper

Cell Nucleation and Growth Study of PP Foaming with CO2 in a Batch-Simulation System

2006-04-03
2006-01-0507
TPO is being used to make automotive parts for its number of advantages: i) low temperature flexibility and ductility, ii) excellent impact/stiffness/flow balance, iii) excellent weatherability, and iv) free-flowing pellet form for easy processing, storage, and handling. However, by foaming TPO, due to its higher rigidity-to-weigh ratio, it would offer additional advantages over the solid counterparts in terms of reduced weight, reduced material cost, and decreased fuel usage without compromising their performance. Since a major component in TPO is polypropylene (PP), understanding PP foaming behaviours is an important step towards understanding TPO foaming. For foam materials, cell density and cell size are two significant parameters that affect their material properties. In this research, we observed the cell nucleation and initial growth behaviours of PP foams blown with CO2 under various experimental conditions in a batch foaming simulation system.
Technical Paper

Foamability of Thermoplastic Vulcanizates (TPVs) with Various Physical Blowing Agents (PBAs)

2006-04-03
2006-01-0972
Thermoplastic Vulcanizate (TPV) is a special class of Thermoplastic Elastomers (TPEs) made of a rubber/plastic polymer mixture in which the rubber phase is highly vulcanized. It is prepared by melt mixing a thermoplastic with an elastomer and by in-situ crosslinking of the rubber phase. Currently, TPV is replacing EPDM rubber dramatically because of the impressive advantages for automotive sealing applications. Some of the advantages of TPV compared to that of EPDM rubber are good gloss, recyclability, improved colorability, shorter cycle time and design flexibility. The development of TPV foaming technology is to fulfill the requirement of achieving lower cost, lighter weight and better fuel economy. Foaming of TPV has not been investigated extensively.
Technical Paper

Impact of Powertrain Type on Potential Life Cycle Greenhouse Gas Emission Reductions from a Real World Lightweight Glider

2017-03-28
2017-01-1274
This study investigates the life cycle greenhouse gas (GHG) emissions of a set of vehicles using two real-world gliders (vehicles without powertrains or batteries); a steel-intensive 2013 Ford Fusion glider and a multi material lightweight vehicle (MMLV) glider that utilizes significantly more aluminum and carbon fiber. These gliders are used to develop lightweight and conventional models of internal combustion engine vehicles (ICV), hybrid electric vehicles (HEV), and battery electric vehicles (BEV). Our results show that the MMLV glider can reduce life cycle GHG emissions despite its use of lightweight materials, which can be carbon intensive to produce, because the glider enables a decrease in fuel (production and use) cycle emissions. However, the fuel savings, and thus life cycle GHG emission reductions, differ substantially depending on powertrain type. Compared to ICVs, the high efficiency of HEVs decreases the potential fuel savings.
Technical Paper

Modelling and Optimization of Plug Flow Mufflers in Emission Control Systems

2017-06-05
2017-01-1782
Large-scale emergency or off-grid power generation is typically achieved through diesel or natural gas generators. To meet governmental emission requirements, emission control systems (ECS) are required. In operation, effective control over the generator’s acoustic emission is also necessary, and can be accomplished within the ECS system. Plug flow mufflers are commonly used, as they provide a sufficient level of noise attenuation in a compact structure. The key design parameter is the transmission loss of the muffler, as this dictates the level of attenuation at a given frequency. This work implements an analytically decoupled solution, using multiple perforate impedance models, through the transfer matrix method (TMM) to predict the transmission loss based on the muffler geometry. An equivalent finite element model is implemented for numerical simulation. The analytical results and numerical results are then evaluated against experimental data from literature.
Technical Paper

A Chemical-Kinetic Approach to the Definition of the Laminar Flame Speed for the Simulation of the Combustion of Spark-Ignition Engines

2017-09-04
2017-24-0035
The laminar burning speed is an important intrinsic property of an air-fuel mixture determining key combustion characteristics such as turbulent flame propagation. It is a function of the mixture composition (mixture fraction and residual gas mass fraction) and of the thermodynamic conditions. Experimental measurements of Laminar Flame Speeds (LFS) are common in literature, but initial pressure and temperature are limited to low values due to the test conditions: typical pressure values for LFS detection are lower than 25 bar, and temperature rarely exceeds 550 K. Actual trends in spark ignition engines are to increase specific power output by downsizing and supercharging, thus the flame front involves even more higher pressure and temperature since the beginning of combustion.
Technical Paper

Heavy Duty Diesel Engine Modeling with Layered Artificial Neural Network Structures

2018-04-03
2018-01-0870
In order to meet emissions and power requirements, modern engine design has evolved in complexity and control. The cost and time restraints of calibration and testing of various control strategies have made virtual testing environments increasingly popular. Using Hardware-in-the-Loop (HiL), Volvo Penta has built a virtual test rig named VIRTEC for efficient engine testing, using a model simulating a fully instrumented engine. This paper presents an innovative Artificial Neural Network (ANN) based model for engine simulations in HiL environment. The engine model, herein called Artificial Neural Network Engine (ANN-E), was built for D8-600 hp Volvo Penta engine, and directly implemented in the VIRTEC system. ANN-E uses a combination of feedforward and recursive ANNs, processing 7 actuator signals from the engine management system (EMS) to provide 30 output signals.
Technical Paper

Development and Calibration of One Dimensional Engine Model for Hardware-In-The-Loop Applications

2018-04-03
2018-01-0874
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.
Technical Paper

Application of Nonlinear Transformations to A/F Ratio and Speed Control in an IC Engine

1999-03-01
1999-01-0858
This paper presents the first application of the global feedback linearization method to an internal combustion (IC) engine. Through the application of this nonlinear control technique, the nonlinear coupled dynamics of the IC engine are globally linearized and decoupled. This represents a significant advance over previously published control approaches which rely on locally linearized dynamic models. With the IC engine dynamics globally linearized and decoupled, outer-loop controllers can be readily designed using simple linear tracking controller design methods, leading to very good dynamic response of three key IC engine outputs, air/fuel ratio, engine speed and manifold air pressure. In this paper, a standard IC engine model from the literature is first transformed to a controllable canonical form, required for the application of the global feedback linearization methods.
Technical Paper

Fuel Effects on Particulate Matter Emissions Variability from a Gasoline Direct Injection Engine

2018-04-03
2018-01-0355
Particulate matter emissions from gasoline direct injection engines are a concern due to the health effects associated with ultrafine particles. This experimental study investigated sources of particulate matter emissions variability observed in previous tests and also examined the effect of ethanol content in gasoline on particle number (PN) concentrations and particle mass (PM) emissions. FTIR measurements of gas phase hydrocarbon emissions provided evidence that changes in fuel composition were responsible for the variability. Exhaust emissions of toluene and ethanol correlated positively with emitted PN concentrations, while emissions of isobutylene correlated negatively. Exhaust emissions of toluene and isobutylene were interpreted as markers of gasoline aromatic content and gasoline volatility respectively.
Journal Article

Geometric and Fluid-Dynamic Characterization of Actual Open Cell Foam Samples by a Novel Imaging Analysis Based Algorithm

2017-10-05
2017-01-9288
Metallic open-cell foams have proven to be valuable for many engineering applications. Their success is mainly related to mechanical strength, low density, high specific surface, good thermal exchange, low flow resistance and sound absorption properties. The present work aims to investigate three principal aspects of real foams: the geometrical characterization, the flow regime characterization, the effects of the pore size and the porosity on the pressure drop. The first aspect is very important, since the geometrical properties depend on other parameters, such as porosity, cell/pore size and specific surface. A statistical evaluation of the cell size of a foam sample is necessary to define both its geometrical characteristics and the flow pattern at a given input velocity. To this purpose, a procedure which statistically computes the number of cells and pores with a given size has been implemented in order to obtain the diameter distribution.
Technical Paper

Kinematic Solution and Force Layout of a Roller Pump with Internal Outlets

2000-03-06
2000-01-0833
The article presents a theoretical analysis of a roller pump design and a summary of the experiments. The pump is to provide high pressure for transmission, accessory drive, and other applications. A theoretical model was built to simulate the motion of the rollers and optimize the design. An experiment was conducted to prove the simulation. The mathematical model was built within constraints of rigid body mechanics. Comprehensive kinematic and force analysis was done through differential equations of motion. Obtained quantitative relationships include, on one hand, pump geometry, speed of rotation, and discharge/suction oil pressure, and, on the other hand, torque, dynamic interaction of relatively moving parts, and kinematic parameters of the roller. The model includes dissipate forces to account for hydraulic effects. Modeling these forces is beyond mechanics of solid body and is not considered at this initial stage of research.
Journal Article

PSO-Based Multidisciplinary Design Optimization of Automotive Assemblies

2017-08-01
2017-01-9682
Widely used in automotive industry, lightweight metallic structures are a key contributor to fuel efficiency and reduced emissions of vehicles. Lightweight structures are traditionally designed through employing the material distribution techniques sequentially. This approach often leads to non-optimal designs due to constricting the design space in each step of the design procedure. The current study presents a novel Multidisciplinary Design Optimization (MDO) framework developed to address this issue. Topology, topography, and gauge optimization techniques are employed in the development of design modules and Particle Swarm Optimization (PSO) algorithm is linked to the MDO framework to ensure efficient searching in large design spaces often encountered in automotive applications. The developed framework is then further tailored to the design of an automotive Cross-Car Beam (CCB) assembly.
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