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Technical Paper

Axle Efficiency Comparison Method and Spin Loss Benefit of Front Axle Disconnect Systems

2020-04-14
2020-01-1412
There are a variety of test protocols associated with vehicle fuel economy and emissions testing. As a result, a number of test protocols currently exist to measure axle efficiency and spin loss. The intent of this technical paper is to describe a methodology that uses a singular axle efficiency and spin loss procedure. The data can then be used to predict the effects on vehicle FE and GHG for a specific class of vehicles via simulation. An accelerated pre-conditioning method using a comparable energy approach has been developed, and can be used to meet the pre-conditioning requirements of different vehicle emission test protocols. A “float to equilibrium” sump temperature approach has been used to produce instantaneous efficiency data, which can be used to more accurately predict vehicle FE and GHG, inclusive of Cold CO2. The “float to equilibrium” approach and “fixed sump temperature” approach has been compared and discussed.
Technical Paper

Fatigue Life Prediction of Short Fiber Composites using FEA Methodology

2020-04-14
2020-01-1308
In automotive industry light weight composite materials improve the fuel economy, vehicle mobility and, increase towing capacity. In this paper, static and fatigue analysis of oil-pan made of short fiber reinforced polymer composite have been studied. FEA methodology has been established to predict the life of short fiber reinforced polymer composite accurately. Oil-pan is made of Zytel 75LG50HSL which is 50% PA66 and 50% glass fiber by weight. The stiffness and fatigue life of oil-pan estimated from FEA simulation is compared to physical test. In order to simulate the fatigue life in FEMFAT, we require accurate fiber orientation, composite fatigue properties from 0°/45°/90° short fiber composite coupon test and stress based on anisotropic material properties. Fiber orientation of oil-pan is predicted using Moldflow by providing gate locations and flow properties. Anisotropic material properties generated using MDS by providing matrix and fiber properties.
Technical Paper

Integrated Regenerative Braking System and Anti-lock Braking System for Hybrid Electric Vehicles & Battery Electric Vehicles

2020-04-14
2020-01-0846
Regenerative braking in hybrid electric vehicles is a critical feature to achieve the maximum fuel economy benefit of hybridization. In order to maximize energy recuperation, it is desired to enable regenerative braking during an Anti-lock Braking System (ABS) event. For certain driveline configurations with a single electric motor connected to the axle shaft through an open differential, it has been observed that the regenerative braking torque can increase the wheel slip during the ABS operation, and significantly impact vehicle dynamics. This negative effect introduced by regen braking during ABS control may also lead to hardware failures, such as breaking a drive shaft. This paper describes development of an integrated regenerative braking and ABS control for hybrid and electric drive vehicles, referred to as RBS-ABS Event Control. This control is intended for drivelines containing a single electric motor connected to the axle shaft through an open differential.
Technical Paper

Mathematical Analysis of Clutch Thermal Energy during Automatic Shifting Coupled with Input Torque Truncation

2020-04-14
2020-01-0967
A step-ratio automatic transmission system alters torque paths through engagement and disengagement of multiple clutches. It adjusts gear ratios to efficiently run torque sources while meeting driver demand. Yet, thermal energy loss during clutch slippage is one of the contributors to the fuel efficiency of a vehicle. In order to optimize drivetrain control strategy, including frequency of shifts, it is important to understand the cost of shift itself. During a power-on upshift, clutch thermal energy is primarily dissipated during inertia phase. The interaction between multiple clutches, coupled with input torque truncation, makes the decomposition of overall energy loss less obvious. This paper systematically presents the mathematical analysis of clutch thermal energy during the inertia phase of a typical single-transition gearshift. In practice, a quicker shift is generally favored, partly because the amount of energy loss is considered smaller.
Technical Paper

Towards Design of Sustainable Smart Mobility Services through a Cloud Platform

2020-04-14
2020-01-1048
People and their communities are looking for transportation solutions that reduce travel time, improve well-being and accessibility, and reduce emissions and traffic congestion. Although new mobility services like ridesharing advertise improvements in these areas, closer inspection has revealed a discrepancy between industry claims and reality. Mobility service providers have the opportunity to leverage connected vehicle and connected device data through cloud-based APIs. We propose a CO2 data analytics framework that functions on top of a cloud platform to provide unique system-level perspectives on operating transportation services, from procuring the most environmentally and people friendly vehicles to scheduling and designing the services based on data insights.
Technical Paper

How well can mPEMS measure gas phase motor vehicle exhaust emissions?

2020-04-14
2020-01-0369
“Real world emissions” is an emerging area of focus in motor vehicle related air quality. These emissions are commonly recorded using portable emissions measurement systems (PEMS) designed for regulatory application, which are large, complex and costly. Miniature PEMS (mPEMS) is a developing technology that can significantly simplify on-board emissions measurement and potentially promote widespread use. Whereas full PEMS use analyzers to record NOx, CO, and HCs similar to those in emissions laboratories, mPEMS tend to use electrochemical sensors and compact spectroscopic detectors for their small size and low cost. The present work evaluates this approach by comparing measurements of NOx, CO, CO2 and HC emissions from five commercial mPEMS to both laboratory and full regulatory PEMS measurements. It further examines the use of vehicle on-board diagnostics data to calculate exhaust flow, as an alternative to on-vehicle exhaust flow measurement.
Technical Paper

How well can mPEMS measure particulate matter motor vehicle exhaust emissions?

2020-04-14
2020-01-0391
Real world emissions are increasingly the standard of comparison for motor vehicle exhaust impact on the environment. The ability to collect such data has thus far relied primarily on full portable emissions measurement systems (PEMS) that are bulky, expensive, and time consuming to set up. The present work examines four compact, low cost, miniature PEMS that offer the potential to expand our ability to record real world exhaust emissions over a larger number of operating conditions and combustion engine applications than currently possible. It specifically addresses the particulate matter (PM) capabilities of these mPEMS, which employ three different methodologies for particle measurement, diffusion charger, optical scattering, and a multiplex process that combines scattering, opacity, and ionization. Their performance is evaluated against solid particle number and PM mass with both vehicle tests and flame generated soot.
Technical Paper

Launch and Lock with Multi-input Multi-Output Converter Control

2020-04-14
2020-01-0262
A torque converter is a type of fluid coupling device used to transfer engine power to the gearbox and driveline. A bypass clutch equipped in a torque converter assembly is a friction element which when fully engaged, can directly connect the engine to the gearbox. The torque converter is an important launch device in an automatic transmission which decouples engine speed from gearbox input speed while provides torque multiplication to drive the vehicle. During partial pedal launch, it is desired to engage the bypass clutch early and reduce the converter slippage in order to reduce power loss and achieve better fuel economy. However, engaging the bypass clutch early and aggressively may disturb the wheel torque and cause an unpleasant driving experience. This paper describes a multi-input multi-output (MIMO) control method to coordinate both engine and converter bypass clutch to simultaneously deliver desired wheel torque and reduce converter slippage.
Technical Paper

Chassis Lightweighting Hole Placement with Weldline Evaluation

2020-04-14
2020-01-0493
Vehicle weight driven design comes amid rising higher fuel efficiency standard, and must meet the criteria - pass Proving ground test events that is equivalent customer usage. CAE Fatigue analysis for proving ground (CFP) is behind a success push to digitally simulate vehicle durability performance in high fidelity. The need for vehicle weight reduction often arises late in vehicle development phases when CAE Methods, time, and tangible cost effective opportunities are limited or non-existent. It is necessary to deploy a new CAE Method to identify opportunities for light-weighting hole placement in Chassis structures to deliver a cost effective light-weighting opportunity with no impact on fatigue life. The successful application of this methodology is on truck frame, which is key structural parts for vehicle chassis to support body and suspension and powertrain.
Technical Paper

Combustion and Emission Characteristics of SI and HCCI Combustion Fueled with DME and OME

2020-04-14
2020-01-1355
DME has been considered an alternative fuel to diesel fuel with promising benefits because of its high reactivity and volatility. Research shows that an engine fueled with DME will produce zero smoke emissions. However, the storage and the handling of the fuel are underlying difficulties owing to its high vapour pressure (530 kPa @ 20 °C). In lieu, OME fuel, a derivate of DME, offers advantages exhibited with DME fuel, all the while being a liquid fuel for engine application. In this work, engine tests are performed to realize the combustion behaviour of DME and OME fuel on a single-cylinder research engine with a compression ratio of 9.2:1. The dilution ratio of the mixture is progressively increased in two manners, allowing more air in the cylinder and applying exhaust gas recirculation. The high reactivity of DME suits the capability to be used in compression ignition combustion whereas OME must be supplied with a supplemental spark to initiate the combustion.
Technical Paper

Hardware-in-the-Loop and Public Road Testing of RLVW and GLOSA Connected Vehicle Applications

2020-04-14
2020-01-1379
Each year, large number of traffic accidents with a large number of injuries and fatalities occur. To reduce these accidents, automotive companies have been developing newer and better active and passive safety measures to increase the safety of passengers. With the developments in connected vehicle infrastructure on the roads and on-board-units for Vehicle to Everything (V2X) connectivity in newer vehicles, V2X communication offers possibilities for preventing accidents as V2X equipped vehicles have situational awareness of other vehicles and road users around them through Vehicle to Vehicle (V2V) and Vehicle to Pedestrian (V2P) communication, and signal phase and timing and map information on signalized intersections through Vehicle to Infrastructure (V2I) communication. Therefore, vehicle on-board computers can calculate an optimal speed profile for fuel economy purposes or prevent crashes related to red light violations.
Technical Paper

Diagnostic Evaluation of Exhaust Gas Recirculation (EGR) System on Gasoline Electric Hybrid Vehicle

2020-04-14
2020-01-0902
Diagnosing the Exhaust Gas Recirculation (EGR) Valve remains one of the most challenging problems in emissions control systems diagnostics. California Air Resources Board (CARB) has started imposing specific requirements on automotive companies since 2011 that required the integration of on-board diagnostics (OBD) monitor for the detection and reporting of this type of control malfunction. In this paper, some methodologies of EGR valve system monitoring are investigated and a novel approach is proposed that shows reliable detection capability compared to the other methods. The proposed method requires certain conditions during deceleration fuel shutoff events to intrusively reactivate the EGR system and determine the obstructed valve condition. The method was evaluated on a 2.5L iVCT engine in an experimental Ford Escape Full Hybrid Electric vehicle. Vehicle results are shown and discussed.
Technical Paper

Cycle-Resolved Cold Start Emissions Characteristics of a 2 liter GDI Engine for the First Several Combustion Cycles

2020-04-14
2020-01-0312
There is keen interest in understanding the origins of engine-out unburned hydrocarbons emitted during SI engine cold start. This is especially true for the first few firing cycles, which can contribute disproportionately to the total emissions measured over standard drive cycles such as the US Federal Test Procedure (FTP). In this study introduces a new methodology for capturing and quantifying unburned hydrocarbon emissions, CO, and CO2 on a cycle-by-cycle basis during an engine cold start. The method was demonstrated by applying it to a 2 liter GTDI engine for cold start conditions at ambient temperatures of approximately 22oC. The entirety of the engine exhaust gas was captured for a predetermined number of firing cycles. By capturing the exhaust of different numbers of firing cycles, from one to five for example, the emissions contribution of each successive cycle was determined on an ensemble average basis.
Technical Paper

Mass Optimization of a Front Floor Reinforcement

2020-01-13
2019-36-0149
Optimization of heavy materials like steel, in order to create a lighter vehicle, it is a major goal among most automakers, since heavy vehicles simply cannot compete with a lightweight model's fuel economy. Thinking this way, this paper shows a case study where the Size Optimization technique is applied to a front floor reinforcement. The reinforcement is used by two different vehicles, a subcompact and a crossover Sport Utility Vehicle (SUV), increasing the problem complexity. The Size Optimization technique is supported by Finite Element Method (FEM) tools. FEM in Computer Aided Engineering (CAE) is a numerical method for solving engineering problems, and its use can help to optimize prototype utilization and physical testing.
Technical Paper

Effects of Exhaust Gas Hydrogen Addition and Oxygenated Fuel Blends on the Light-Off Performance of a Three-Way Catalyst

2019-12-19
2019-01-2329
A significant amount of harmful emissions pass unreacted through catalytic after-treatment devices for IC engines before the light-off temperature is reached, despite the high conversion efficiency of these systems in fully warm conditions. Further tightening of fleet targets and worldwide emission regulations will make a faster catalyst light-off to meet legislated standards hence reduce the impact of road transport on air quality even more critical. This work investigates the effect of adding hydrogen (H2) at levels up to 2500 ppm into the exhaust gases produced by combustion of various oxygenated C2-, C4- and renewable fuel molecules blended at 20 % wt/wt with gasoline on the light-off performance of a commercially available three-way catalyst (TWC) (0.61 L, Pd/Rh/Pt - 19/5/1, 15g). The study was conducted on a modified naturally aspirated, 1.4 L, four-cylinder, direct-injected, spark-ignition engine.
Technical Paper

Piston Bowl Geometry Effects on Combustion Development in a High-Speed Light-Duty Diesel Engine

2019-09-09
2019-24-0167
In this work we studied the effects of piston bowl design on combustion in a small-bore direct-injection diesel engine. Two bowl designs were compared: a conventional, omega-shaped bowl and a stepped-lip piston bowl. Experiments were carried out in the Sandia single-cylinder optical engine facility, with a medium-load, mild-boosted operating condition featuring a pilot+main injection strategy. CFD simulations were carried out with the FRESCO platform featuring full-geometric body-fitted mesh modeling of the engine and were validated against measured in-cylinder performance as well as soot natural luminosity images. Differences in combustion development were studied using the simulation results, and sensitivities to in-cylinder flow field (swirl ratio) and injection rate parameters were also analyzed.
Technical Paper

Developing a Real-World, Second-by-Second Driving Cycle Database through Public Vehicle Trip Surveys

2019-07-08
2019-01-5074
Real-world second-by-second vehicle driving cycle data is very important for vehicle research and development. A project solely dedicated to generating such information would be tremendously costly and time consuming. Alternatively, we developed such a database by utilizing two publicly available passenger vehicle travel surveys: 2004-2006 Puget Sound Regional Council (PSRC) Travel Survey and 2011 Atlanta Regional Commission (ARC) Travel Survey. The surveys complement each other - the former is in low time resolution but covers driver operation for over one year whereas the latter is in high time resolution but represents only one-week-long driving operation. After analyzing the PSRC survey, we chose 382 vehicles, each of which continuously operated for one year, and matched their trips to all the ARC trips. The matching is carried out based on trip distance first, then on average speed, and finally on duration.
Journal Article

Optimal Pressure Relief Groove Geometry for Improved NVH Performance of Variable Displacement Oil Pumps

2019-06-05
2019-01-1548
Variable Displacement Oil Pump (VDOP) is becoming the design of choice for engine friction reduction and fuel economy improvement. Unfortunately, this pump creates excessive pressure ripples, at the outlet port during oil pump shaft rotation, causing oscillating forces within the lubrication system and leading to the generation of objectionable tonal noises and vibrations. In order to minimize the level of noise, different vanes spacing and porting geometries are used. Moreover, an oil pressure relief groove can be added, at the onset of the high pressure port, to achieve this goal. This paper presents an optimization method to identify the best geometry of the oil pressure relief groove. This method integrates adaptive meshing, 3D CFD simulation, Matlab routine and Genetic Algorithm based optimization. The genetic algorithm is used to create the required design space in order to perform a multi-objective optimization using a large number of parameterized groove geometries.
Journal Article

Machine Learning Algorithm for the Prediction of Idle Combustion Uniformity

2019-06-05
2019-01-1551
Combustion stability is a key contributor to engine shake at idle speed and can impact the overall perception of vehicle quality. The sub-firing harmonics of the combustion torque are used as a metric to assess idle shake and are, typically, measured at different levels of engine break mean effective pressure (BMEP). Due to the nature of the combustion phenomena at idle, it is clear that predicting the cycle-to-cycle and cylinder-to-cylinder combustion pressure variations, required to assess the combustion uniformity, cannot be achieved with the state of the art simulation technology. Inspired by the advancement in the field of machine learning and artificial intelligence and by the availability of a large amount of measured combustion test data, this paper explores the performance of various machine learning algorithms in predicting the idle combustion uniformity.
Technical Paper

The Effect of Friction Modifiers and DI Package on Friction Reduction Potential of Next Generation Engine Oils: Part II Aged Oils

2019-04-02
2019-01-0303
Engine oil plays an important role in improving fuel economy of vehicles by reducing frictional losses in an engine. Our previous investigation explored the friction reduction potential of next generation engine oils by looking into the effects of friction modifiers and dispersant Inhibitor packages when engine oil was fresh. However, engine oil starts aging the moment engine start firing because of high temperature and interactions with combustion gases. Therefore, it is more relevant to investigate friction characteristics of aged oils. In this investigation, oils were aged for 5000 miles in taxi cab application.
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