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Automated Driving System Safety: Miles for 95% Confidence in “Vision Zero”

Driving Safety Consulting LLC-Richard Allen Young
  • Technical Paper
  • 2020-01-1205
To be published on 2020-04-14 by SAE International in United States
Engineering reliability models from RAND, MobilEye, and Volvo concluded that billions of miles of on-road data were required to validate that the real-world fatality rate of an “Automated Driving System-equipped vehicle” (AV) fleet for an improvement over human-driven conventional vehicles (CV). RAND said 5 billion miles for 20%, MobileEye 30 billion for 99.9%, and Volvo 5 billion for 50% improvement. All these models used the Gaussian distribution, which is inaccurate for low crash numbers. The current study proposes a new epidemiologic method and criterion to validate real-world AV data with 95% confidence for zero to ten fatal crashes. The upper confidence limit (UL) of the AV fatal crash rate has to be lower than the CV fatal crash rate with 95% confidence. That criterion is met if the UL of the AV fatal crash incidence rate ratio estimate is below one. That UL was estimated using the mid-P exact method for calculating confidence limits for a dual Poisson process, using a one-tailed 95% confidence level. The required AV mileage was adjusted by trial and error…
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Impact of fuel octane quality on various advanced vehicle technologies

Shell Global Solutions (Deutschland)-Caroline Magdalene Zinser, Patrick Haenel
Shell Global Solutions (UK)-Alastair Smith
  • Technical Paper
  • 2020-01-0619
To be published on 2020-04-14 by SAE International in United States
Fuel with higher octane content is playing a key role in optimising engine performance by allowing a more optimal spark timing which leads to increased engine efficiency and lower CO2 emissions. In a previous study the impact of octane was investigated with a vehicle fleet of 20 vehicles using market representative fuels, varying from RON 91 to 100. The resulting data showed a clear performance and acceleration benefit when higher RON fuel was used. In this follow-up study 10 more vehicles were added to the database. The vehicle fleet was extended to be more representative of Asian markets, thus broadening the geographical relevance of the database, as well as adding vehicles with newer technologies such as boosted down-sized direct injection engines, or higher compression ratio engines. Eight different fuel combinations varying in RON were tested, representing standard gasoline and premium gasoline in different markets around the world. The new results augment our previously published octane study and result in a vehicle fleet dataset comprising 30 cars from 18 different automotive manufactures. Two key metrics were…
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Development and demonstration of a class 6 range-extended electric vehicle for commercial pickup and delivery operation

Cummins Inc.-John Kresse, Ke Li, Jesse Dalton
National Renewable Energy Laboratory-Matthew A. Jeffers, Eric Miller, Kenneth Kelly
  • Technical Paper
  • 2020-01-0848
To be published on 2020-04-14 by SAE International in United States
Range-extended hybrids are an attractive option for medium- and heavy-duty (M/HD) commercial vehicle fleets because they offer the efficiency of an electrified powertrain and accessories with the range of a conventional diesel powertrain. The vehicle essentially operates as if it was purely electric for most trips, while ensuring that all commercial routes can be completed in any weather conditions or geographic terrain. Fuel use and point-source emissions can be significantly reduced, and in some cases eliminated, as many shorter routes can be fully electrified with this architecture. Under a U.S. Department of Energy award for M/HD Vehicle Powertrain Electrification, Cummins has developed a plug-in hybrid electric (PHEV) class 6 truck with a range-extending engine designed for pickup and delivery application. The National Renewable Energy Laboratory (NREL) assisted by developing a representative work day drive cycle for class 6 operation and adapting it to enable track testing. A novel, automated driving system was developed and utilized by Southwest Research Institute (SwRI) to improve the repeatability of vehicle track testing used to quantify vehicle energy consumption. Cummins…
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Statistical Analysis of City Bus Driving Cycle Features for the Purpose of Multidimensional Driving Cycle Synthesis

University of Zagreb-Jakov Topić, Branimir Skugor, Josko Deur
  • Technical Paper
  • 2020-01-1288
To be published on 2020-04-14 by SAE International in United States
Driving cycles are typically defined as time profiles of vehicle velocity, and as such they reflect basic driving characteristics. They have a wide application from the perspective of both conventional and electric road vehicles, ranging from prediction of fuel/energy consumption (e.g. for certification purposes), estimation of greenhouse gas and pollutant emissions to selection of optimal vehicle powertrain configuration and design of its control strategy. In the case of electric vehicles, the driving cycles are also applied to determine effective vehicle range, battery life period, and charging management strategy. Nowadays, in most applications artificial certification driving cycles are used. As they do not represent realistic driving conditions, their application results in generally unreliable estimates and analyses. Therefore, recent research efforts have been directed towards development of statistically representative synthetic driving cycles derived from recorded GPS driving data. The state-of-the-art synthesis approach is based on Markov chains, typically including vehicle velocity and acceleration as Markov chain states. However, apart from the vehicle velocity and acceleration, a road slope and vehicle mass are also shown to significantly impact…
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Real-Time Optimization of Control Strategy for a Range-Extended Electric Vehicle using Reinforcement Learning Algorithm and Neural Network

Nipun Mittal, Aditya Pundlikrao Bhagat, Shubham Bhide, Bharadwaj Acharya, Bin Xu, Chris Paredis
  • Technical Paper
  • 2020-01-1190
To be published on 2020-04-14 by SAE International in United States
Range-Extended Electric Vehicles (REEV) have seen an increase in market share in the past decade. This trend can be attributed to an increased market shift towards electrified powertrains while addressing the range anxiety usually associated with an electric vehicle. In such a scenario, operating the vehicle efficiently is critical to meet the CAFÉ standards. This energy optimization problem becomes even more critical if the vehicle is being operated as part of a fleet as minimal energy savings get compounded across the fleet and result in significant savings for the service provider and more affordability for the customers. There is also an upward trend in ride sharing services operated by fleet owners like Uber and Waymo. Fleet vehicles offer the unique advantage of availability of large amounts of data about the consumer usage pattern in a given area. When coupled with traffic density and immediate destination of the current consumer of the vehicle, the data can assist the improvement of fuel economy while a traditional rule-based strategy can hardly take advantage of the data. Deep Orange…
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Understanding Charging Flexibility of Shared Autonomous Electric Vehicle Fleets

National Renewable Energy Laboratory-Matthew Moniot, Yanbo Ge, Nicholas Reinicke, Alex Schroeder
  • Technical Paper
  • 2020-01-0941
To be published on 2020-04-14 by SAE International in United States
The combined anticipated trends of vehicle sharing, autonomous control, and powertrain electrification are poised to disrupt the current paradigm of predominately gasoline vehicles with low levels of utilization. Shared, autonomous, electric vehicle (SAEV) fleets, which encompass all three of these trends, have garnered significant interest among the research community due to the opportunity for low-cost mobility with congestion and emissions reductions. This paper explores the charging loads demanded by SAEV fleets in response to servicing personal light-duty vehicle travel demand in four major United States metropolitan areas: Detroit, Austin, Washington DC, and Miami. A coordinated charging model is introduced which minimizes fleet charging costs and corresponding plant emissions in response to different renewable energy penetration rates and shares of personal trip demand served (between 1% and 25%). The relationship between trip demand by time of day, electricity price by time of day, and SAEV fleet size versus overall charging flexibility is explored for each city. SAEV results are presented across various scenarios assuming fleetwide attempts to minimize charging costs while still constrained by offering adequate…
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Using Vehicle Specifications to Gain Insights into Different Automotive Market Requirements

Mahindra & Mahindra, Ltd.-Lemuel Paulraj, Saravanan Muthiah
  • Technical Paper
  • 2020-01-1283
To be published on 2020-04-14 by SAE International in United States
Determination of vehicle specifications (for example, powertrain sizing) is one of the fundamental steps in any new vehicle development process. The vehicle system engineer needs to select an optimum combination of vehicle, engine and transmission characteristics based on the product requirements received from Product Planning (PP) and Marketing teams during concept phase of any vehicle program. This process is generally iterative and requires subject matter expertise. For example, accurate powertrain sizing is essential to meet the required fuel economy (FE), performance and emission targets for different vehicle configurations. This paper analyzes existing vehicle specifications (Passenger Cars/SUVs - Gasoline/Diesel) in different automotive markets (India, Europe, US, Japan) and aims to determine underlying trends across them. Scatter band analysis is carried out for specifications such as vehicle kerb weight (WT), vehicle length (L), vehicle width (W), vehicle height (H), footprint area (FPA), engine cubic capacity (CC) and engine power (P). CC/WT vs FE, CC/FPA vs FE, P/WT vs FE, FPA/(LXW), CC/(FPAXH), FPAXH and WXH trends are analyzed amongst others. It is interesting to note that similarities exist…
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Continuous integration as mandatory puzzle piece for the success of autonomous vehicles

iProcess LLC-Florian Rohde
  • Technical Paper
  • 2020-01-0087
To be published on 2020-04-14 by SAE International in United States
The transition to autonomous driving technology is is widely discussed topic today. In order to make autonomous vehicles work safely in the long run it will be a necessity to keep their software up to date at any time. Continuous integration methods need to get implemented into the automotive system development in order to keep up with the pace needed to make the new technology a success, and accepted by the users. With today’s traditional release methods vehicle updates are not deployed fast enough, a newly discovered corner case or glitch could restrict the usage of entire fleets for long time. In order to achieve turn around times measured in hours and not in weeks a sophisticated end to end continuous integration and validation process is needed on the highest system integration level. The development process has to contain smart branching strategies for fast turn around, it is mandatory to have a frozen and stable branch to release hotfixes in case of need, a validation branch with feature lock in order to stabilize, and a…
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Design of a Mild Hybrid Electric Vehicle with CAVs Capability for the MaaS Market

Mississippi State University-Amine Taoudi, Moinul Shahidul Haque, Randolph Follett
University of Wisconsin-Madison-Andrea Strzelec
  • Technical Paper
  • 2020-01-1437
To be published on 2020-04-14 by SAE International in United States
There is significant potential for connected and autonomous vehicles to impact vehicle efficiency, fuel economy, and emissions, especially for hybrid-electric vehicles. These improvements could have large-scale impact on oil consumption and air-quality if they deployed in large Mobility-as-a-Service or ride-sharing fleets. As part of the US Department of Energy's current Advanced Vehicle Technology Competition (AVCT), EcoCAR: The Mobility Challenge, Mississippi State University’s EcoCAR Team is redesigning and doing the development work necessary to convert a conventional gasoline spark-ignited 2019 Chevy Blazer into a hybrid-electric vehicle with SAE Level 2/3 autonomy. The target consumer segments for this effort are the Mobility-as-a-Service fleet owners, operators and riders. To accomplish this conversion, the MSU team is implementing a P4 mild hybridization strategy that is expected to result in a 30% increase in fuel economy over the stock Blazer. Matlab models of the vehicle system shows the potential for additional improvement with the use of connected and autonomous features in the vehicle. This paper presents the design rationale for selection of the P4 strategy, vehicle modeling, and fuel economy…
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Comparison of EVSE management systems for sites with limited electrical infrastructure

Sacramento Municipal Utility District-Dwight MacCurdy, Carol D. Kay, Karun Kumar, Deepak J. Aswani
  • Technical Paper
  • 2020-01-0532
To be published on 2020-04-14 by SAE International in United States
California leads the country in electric vehicle (EV) adoption. As of 2018, over 6% of annual new vehicle registrations are EVs in California. As EVs become more prevalent in the overall vehicle population, more employers are offering workplace charging as a benefit. Additionally, the fleet segment in Sacramento is also experiencing a transition to electrification because of the attractive total cost of ownership associated with EVs and Sacramento’s interest in cutting greenhouse gas emissions to net zero by 2045. Charging infrastructure for fleets and workplace charging tends to have greater complexity than the residential model of 1 or 2 EVSE per garage. The installed cost of EV charging stations can vary widely, depending on site specific conditions and the number and type of EV charging stations to be installed. The cost can be as much as $10,000 per EV charging station, for Level 1 or Level 2 EVSE, if panel or switch gear upgrades are needed or if trenching is required. These infrastructure costs can pose a significant barrier to EV adoption for fleet operators…