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Technical Paper

Refinement and Validation of the Thermal Stratification Analysis: A post-processing methodology for determining temperature distributions in an experimental HCCI engine

2014-04-01
2014-01-1276
Refinements were made to a post-processing technique, termed the Thermal Stratification Analysis (TSA), that couples the mass fraction burned data to ignition timing predictions from the autoignition integral to calculate an apparent temperature distribution from an experimental HCCI data point. Specifically, the analysis is expanded to include all of the mass in the cylinder by fitting the unburned mass with an exponential function, characteristic of the wall-affected region. The analysis-derived temperature distributions are then validated in two ways. First, the output data from CFD simulations are processed with the Thermal Stratification Analysis and the calculated temperature distributions are compared to the known CFD distributions.
Technical Paper

Review of 2013 U.S. Retail Biodiesel Blends Quality Survey

2014-04-01
2014-01-1379
Biodiesel is a domestic, renewable fuel for diesel engines and is made from agricultural co-products such as soybean oil, rapeseed oil, palm oil and other natural oils. Biodiesel is a cleaner burning fuel that is biodegradable and non-toxic compared to petroleum diesel. Biodiesel has become a major alternative fuel for automotive applications and is critical for lowering US dependence on foreign oil and attain energy security. Vehicle manufacturers have developed new vehicle and diesel engine technologies compatible with B6-B20 biodiesel blends meeting ASTM D7467 specifications. Field warranty and validation tests have shown significant concerns with use of poor quality biodiesel fuels including fuel system deposits, engine oil deterioration, and efficiency loss of the after treatment system. Maintaining good quality of biodiesel is critical for success as a commercial fuel.
Journal Article

Vehicle Spaciousness and Packaging Efficiency

2014-04-01
2014-01-0348
With the ever increasing pressure to improve the fuel economy of vehicles, there has been a corresponding interest in reducing the mass and size of vehicles. While mass is easily quantifiable, vehicle size, particularly the notion of “interior space” as perceived by the customer, is not. This paper explores different ways in which vehicle spaciousness can be quantified and explores new metrics based on customer verbatims. A novel ‘spaciousness calculator’ combines individual metrics to provide a singular holistic rating for spaciousness, useful during vehicle development. Beyond spaciousness, the paper discusses techniques to quantify the ‘packaging efficiency’ of a vehicle; this allows engineers to maximize the interior space for a given exterior size.
Journal Article

Advancement in Vehicle Development Using the Auto Transfer Path Analysis

2014-04-01
2014-01-0379
This paper presents the most recent advancement in the vehicle development process using the one-step or auto Transfer Path Analysis (TPA) in conjunction with the superelement, component mode synthesis, and automated multi-level substructuring techniques. The goal is to identify the possible ways of energy transfer from the various sources of excitation through numerous interfaces to given target locations. The full vehicle model, consists of superelements, has been validated with the detailed system model for all loadcases. The forces/loads can be from rotating components, powertrain, transfer case, chain drives, pumps, prop-shaft, differential, tire-wheel unbalance, road input, etc., and the receiver can be at driver/passenger ears, steering column/wheel, seats, etc. The traditional TPA involves two solver runs, and can be fairly complex to setup in order to ensure that the results from the two runs are consistent with subcases properly labeled as input to the TPA utility.
Technical Paper

Effect of Pre-treatment on Corrosion Performance of AZ31B Magnesium Alloy Panel

2010-04-12
2010-01-0725
AZ31B Mg sheet is being considered for automotive applications. This study investigates the effect of pre-treatments, such as heat-treatments and surface treatments, on the corrosion performance of AZ31B sheet, with a goal of learning which pre-treatment can improve corrosion resistance of the sheet material in production. It is found that the heat-treatment and oxidation during a warm and hot forming (WHF) process will not deteriorate the corrosion performance of the AZ31B sheet; polishing and acid etching can clean the surface and significantly increase the corrosion resistance, but corrosion can be accelerated by sandblasting which contaminates the surface. The change in corrosion performance can be associated with surface cleaning or contamination of the sheet by these pre-treatments. Furthermore, the influence of a pre-treatment on the uncoated AZ31B sheet may affect its corrosion behavior after coating.
Technical Paper

Power Capability Testing of a Lithium-ion Battery Using Hardware in the Loop

2010-04-12
2010-01-1073
The energy storage system (ESS) is the key enabler to hybrid electric vehicles (HEVs) that offer improved fuel economy and reduced vehicle emissions. The power capability of a battery has significant impact on the fuel economy of HEVs. This paper presents the power capability testing of a lithium-ion battery with a conventional metal oxide cathode using the hardware in the loop (HIL) at a wide range of charge/discharge conditions and at different temperatures. The achieved test results provide critical data of battery power characteristics and effectively accelerate the development of battery power prediction algorithm.
Journal Article

Subsystem Rollover Tests for the Evaluation of ATD Kinematics and Restraints

2010-04-12
2010-01-0518
The development of a repeatable dynamic rollover test methodology with meaningful occupant protection performance objectives has been a longstanding and unmet challenge. Numerous studies have identified the random and chaotic nature of rollover crashes, and the difficulty associated with simulating these events in a laboratory setting. Previous work addressed vehicle level testing attempting to simulate an entire rollover event but it was determined that this test methodology could not be used for development of occupant protection restraint performance objectives due to the unpredictable behavior of the vehicle during the entire rollover event. More recent efforts have focused on subsystem tests that simulate distinct phases of a rollover event, up to and including the first roof-to-ground impact.
Technical Paper

AUTOSAR Software Platform Adoption: Systems Engineering Strategies

2014-04-01
2014-01-0289
AUTOSAR(AUTomotive Open System ARchitecture) establishes an industry standard for OEMs and the supply chain to manage growing complexity to the automotive electronics domain. Increased focus on software based features will prove to be a key differentiator between vehicle platforms. AUTOSAR serves to standardize automotive serial data communication protocols, interaction with respect to hardware peripherals within an ECU and allow ECU implementer to focus on development of unique customer focused features that distinguish product offerings. Adoption strategy and impact assessment associated with leveraging AUTOSAR for an E/E Architecture and the potential challenges that need to be considered will be described in this publication. This publication will also illustrate development strategies that need to be considered w.r.t deploying AUTOSAR like data exchange, consistency to BSW software implementation, MCAL drivers etc.
Technical Paper

A Rough Road Ride Simulation Assessment with Flexible Vehicle Body

2014-04-01
2014-01-0112
A rough road ride assessment provides an insightful evaluation of vehicle responses beyond the frequency range of suspension or steering modes. This is when body structure influence on the vehicle performance can be detected by vehicle occupants. In this paper, a rough road is used to evaluate vehicle ride performance and multi-body simulation (MBS) models are developed along with finite-element (FE) representations of the vehicle body and structure. To produce high fidelity simulation results in the frequency range of interest, various vehicle subsystem modeling contents are examined. A case study of a vehicle model with two different structures is provided. Time histories and frequency based analyses are used to obtain insights into the effects of body structure on vehicle responses. Finally, two metrics (‘Isolation’ and ‘Shake’) are used to distinguish the vehicle ride performance.
Journal Article

Design Optimization, Development and Manufacturing of General Motors New Battery Electric Vehicle Drive Unit (1ET35)

2014-04-01
2014-01-1806
The General Motors (GM) 1ET35 drive unit is designed for an optimum combination of efficiency, performance, reliability, and cost as part of the propulsion system for the 2014 Chevrolet Spark Electric Vehicle (EV) [1]. The 1ET35 drive unit is a coaxial transaxle arrangement which includes a permanent-magnet (PM) electric motor and a low loss single-planetary transmission and is the sole source of propulsion for the battery-only electric vehicle (BEV) Spark. The 1ET35 is designed with experience gained from the first modern production BEV, the 1996 GM EV1. This paper describes the design optimization and development of the 1ET35 and its electric motor that will be made in the United States by GM. The high torque density electric motor design is based on high-energy permanent magnets that were originally developed by GM in connection with the EV1 and GM bar-wound stator technology introduced in the 2Mode Hybrid electric transmission, used in the Chevrolet Volt and in GM eAssist systems.
Technical Paper

Shudder and Frictional Characteristics Evaluation of Dual Clutch Transmission Fluids

2014-04-01
2014-01-1988
Under the initiative of The United States Council for Automotive Research LLC (USCAR) [1], we have developed and run comprehensive friction tests of dual clutch transmission fluids (DCTFs). The focus of this study is to quantify the anti-shudder durability over a simulated oil life of 75,000 shifts. We have evaluated six DCT fluids, including 2 fluids with known field shudder performance. Six different tests were conducted using a DC motor-driven friction test machine (GK test bench): 1. Force Controlled Continuous Slip, 2. Dynamic Friction, 3. Speed controlled Acceleration-Deceleration, 4. Motor-torque controlled Acceleration-Deceleration, 5. Static Friction, and 6. Static Break-Away. The test fluids were aged (with the clutch system) on the test bench to create a realistic aging of the entire friction system simultaneously.
Technical Paper

Optimization of Diesel Oxidation Catalyst (DOC) on Passenger Cars to Improve Emission Robustness

2015-04-14
2015-01-1013
Emission compliance at the production level has been a challenge for vehicle manufacturers. Diesel oxidation catalyst (DOC) plays a very important role in controlling the emissions for the diesel vehicles. Vehicle manufacturers tend to ‘over design’ the diesel oxidation catalyst to ‘absorb’ the production variations which seems an easier and faster solution. However this approach increases the DOC cost phenomenally which impacts the overall vehicle cost. The main objective of this paper is to address the high variation in CO tail pipe emissions which were observed on a diesel passenger car during development. This variation was posing a challenge in consistently meeting the internal product requirement/specification.
Technical Paper

Energy Efficiency Impact of Localized Cooling/Heating for Electric Vehicle

2015-04-14
2015-01-0352
The present paper reports on a study of the HVAC energy usage for an EREV (extended range electric vehicle) implementation of a localized cooling/heating system. Components in the localized system use thermoelectric (TE) devices to target the occupant's chest, face, lap and foot areas. A novel contact TE seat was integrated into the system. Human subject comfort rides and a thermal manikin in the tunnel were used to establish equivalent comfort for the baseline and localized system. The tunnel test results indicate that, with the localized system, HVAC energy savings of 37% are achieved for cooling conditions (ambient conditions greater than 10 °C) and 38% for heating conditions (ambient conditions less than 10 °C), respectively based on an annualized ambient and vehicle occupancy weighted method. The driving range extension for an electric vehicle was also estimated based on the HVAC energy saving.
Technical Paper

Using Simulation to Quantify Sine with Dwell Maneuver Test Metric Variability

2008-04-14
2008-01-0590
The Sine with Dwell (SWD) maneuver is the basis for the NHTSA FMVSS-126 regulation. When put into effect, all vehicles under 10,000 lbs GVWR will need to pass this test. Understanding the variability in the yaw rate ratio and lateral displacement test metrics is important for vehicle design. Anything that influences vehicle handling can affect test metric variability. Vehicle handling performance depends largely on vertical tire patch loads, tire force and moment behavior, on slip angle, and camber angle. Tire patch loads are influenced, among other things, by weight distribution and (quasi-static and dynamic) roll-couple distribution. Tire force and moment relationships have a distinct shapes, but they all commonly rise to a peak value at a given slip angle value and then fall off with increasing slip angle. Severe handling maneuvers, like the SWD operate at slip angles that are at, or above, the peak lateral force.
Journal Article

Internal Combustion Engine - Automatic Transmission Matching for Next Generation Power Transfer Technology Development in Automotive Applications

2016-04-05
2016-01-1099
Development of the next generation internal combustion engines and automatic transmissions for automotive applications is a mandatory powertrain engineering activity required now and in the coming years to meet forthcoming global emissions regulations. This paper details a preliminary investigation into possible synergies for fuel consumption reduction considering emerging automotive technologies integrated into the next generation combustion engine and automatic transmission architectures. A range of hypothetical gasoline engines were created and paired with a generalized set of step gear automatic transmissions designed to meet the performance requirements of high volume longitudinal full size truck application. These designs were then run through a design of experiments orthogonal array for prediction of fuel consumption on the WLTP test schedule and stand still acceleration to 100 kph.
Technical Paper

Directional Mahalanobis Distance and Parameter Sensitivities

2016-04-05
2016-01-0289
Mahalanobis Distance (MD) is gaining momentum in many fields where classification, statistical pattern recognition, and forecasting are primary focus. It is a multivariate method and considers correlation relationships among parameters for computing generalized distance measure to separate groups or populations. MD is a useful statistic in multivariate analysis to test that an observed random sample is from a multivariate normal distribution. This capability alone enables engineers to determine if an observed sample is an outlier (defect) that falls outside the constructed (good) multivariate normal distribution. In Mahalanobis-Taguchi System (MTS), MD is suitably scaled and used as a measure of severity in abnormality assessment. It is obvious that computed MD depends on values of parameters observed on a random sample. All parameters may not equally impact MD. MD could be highly sensitive with respect to some parameters and less sensitive to some other parameters.
Technical Paper

Next Generation “Voltec” Charging System

2016-04-05
2016-01-1229
The electric vehicle on-board charger (OBC) is responsible for converting AC grid energy to DC energy to charge the battery pack. This paper describes the development of GM’s second generation OBC used in the 2016 Chevrolet Volt. The second generation OBC provides significant improvements in efficiency, size, and mass compared to the first generation. Reduced component count supports goals of improved reliability and lower cost. Complexity reduction of the hardware and diagnostic software was undertaken to eliminate potential failures.
Journal Article

Development of Hybrid-Electric Propulsion System for 2016 Chevrolet Malibu

2016-04-05
2016-01-1169
GM has developed an all-new gasoline-electric hybrid powertrain for the model year 2016 Chevrolet Malibu Hybrid vehicle, which was designed to achieve excellent fuel economy, performance, and drive quality. The powertrain shares the transmission architecture with the 2016 Chevrolet Volt extended range electric vehicle, but includes changes to optimize the system for engine driven charge sustaining operation in the range of conditions represented by the US EPA 5 cycle fuel economy tests. In this paper, we describe the Malibu Hybrid propulsion system features and components, including the battery pack, transaxle, electric motors and power electronics, engine, and thermal system. The modifications between the Volt and Malibu Hybrid propulsion systems are discussed and explained as resulting from the differences between the primarily electric and gasoline powered applications.
Journal Article

Locating Wire Short Fault for In-Vehicle Controller Area Network with Resistance Estimation Approach

2016-04-05
2016-01-0065
Wire shorts on an in-vehicle controller area network (CAN) impact the communication between electrical control units (ECUs), and negatively affects the vehicle control. The fault, especially the intermittent fault, is difficult to locate. In this paper, an equivalent circuit model for in-vehicle CAN bus is developed under the wire short fault scenario. The bus resistance is estimated and a resistance-distance mapping approach is proposed to locate the fault. The proposed approach is implemented in an Arduino-based embedded system and validated on a vehicle frame. The experimental results are promising. The approach presented in this paper may reduce trouble shooting time for CAN wire short faults and may enable early detection before the customer is inconvenienced.
Journal Article

Chevrolet Volt Electric Utilization

2015-04-14
2015-01-1164
Evaluation of one year of in-use operating data from first generation Chevrolet Volt Extended-Range Electric Vehicle (E-REV) retail customers determined trip initial Internal Combustion Engine (ICE) starts were reduced by 70% relative to conventional vehicles under the same driving conditions. These Volt drivers were able to travel 74% of their total miles in EV without requiring the ICE's support. Using this first generation Volt data, performance of the second generation Volt is projected. The Southern California Association of Governments (SCAG) Regional Travel Survey (RTS) data set was also processed to make comparisons between realistic PHEV constraints and E-REV configurations. A Volt characteristic E-REV was found to provide up to 40 times more all-electric trips than a PHEV over the same data set.
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