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Energy Efficient Maneuvering of Connected and Automated Vehicles

Southwest Research Institute-Sankar Rengarajan, Scott Hotz, Jayant Sarlashkar, Stanislav Gankov, Piyush Bhagdikar, Michael C. Gross, Charles Hirsch
  • Technical Paper
  • 2020-01-0583
To be published on 2020-04-14 by SAE International in United States
Onboard sensing and external connectivity using Vehicle-to-Vehicle (V2V), Vehicle-to-Infrastructure (V2I) and Vehicle-to-Everything (V2X) technologies will allow a vehicle to "know" its future operating conditions with some degree of certainty, greatly narrowing prior information gaps. The increased development of such Connected and Automated Vehicle (CAV) systems, currently used mostly for safety and driver convenience, presents new opportunities to improve the energy efficiency of individual vehicles. The NEXTCAR program is one such initiative by the Advanced Research Projects Agency – Energy (ARPA-E) to developed advanced vehicle dynamics and powertrain control technologies that leverage such connected information streams. Southwest Research Institute (SwRI) in collaboration with Toyota and University of Michigan is currently working on improving energy consumption of a Toyota Prius Prime 2017 by 20%. This paper provides an overview of the various algorithms that have been developed to achieve the energy consumption target. A breakdown of how individual algorithms contribute to the overall target is presented. The team built a specialized test-bed called CAV dynamometer that integrates a traffic simulator and a hub dynamometer for testing the…
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Use of Nitric Acid to Control the NO2:NOX Ratio Within the Exhaust Composition Transient Operation Laboratory Exhaust Stream

Southwest Research Institute-Robert Henderson, Ryan Hartley, Cary Henry
  • Technical Paper
  • 2020-01-0371
To be published on 2020-04-14 by SAE International in United States
The Exhaust Composition Transient Operation Laboratory (ECTO-Lab) is a burner system developed at Southwest Research Institute (SwRI) for simulation of IC engine exhaust. The current system design requires metering and combustion of nitromethane in conjunction with the primary fuel source as the means of NOX generation. While this method affords highly tunable NOX concentrations even over transient cycles, no method is currently in place for dictating the speciation of nitric oxide (NO) and nitrogen dioxide (NO2) that constitute the NOX mixture. NOX generated through combustion of nitromethane is dominated by NO, and generally results in a NO2:NOX ratio of <5 %. Generation of any appreciable quantities of NO2 is therefore dependent on an oxidation catalyst to oxidize a fraction of the NO to NO2. Presented within this manuscript is a method for precise control of the NO2:NOX ratio within the ECTO-Lab exhaust stream by using nitric acid as the NOX precursor molecule in lieu of nitromethane. While decomposition of nitromethane generates NO as the dominate component of the NOX mixture, nitric acid decomposition produces primarily…
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Electronic Control of Brake and Accelerator Pedals for Precise Efficiency Testing of Electrified Vehicles

Southwest Research Institute-Michael C. Gross, Jonathan Hamermesh, Kyle Jonson, Joshua Alden
  • Technical Paper
  • 2020-01-1282
To be published on 2020-04-14 by SAE International in United States
Efficiency testing of hybrid-electric vehicles is challenging, because small run-to-run differences in pedal application can change when the engine fires or the when the friction brakes supplement regenerative braking, dramatically affecting fuel use or energy regeneration. Electronic accelerator control has existed for years, thanks to the popularity of throttle-by-wire (TBW). Electronic braking control is less mature, since most vehicles don’t use brake-by-wire (BBW). Computer braking control typically uses a mechanical actuator (which may suffer backlash or misalignment) or braking the dynamometer rather than the vehicle (which doesn’t yield regeneration). The growth of electrification and autonomy provides the means to implement electronic brake control. Electrified vehicles use BBW to control the split between friction and regenerative braking. Automated features, e.g. adaptive cruise control, require BBW to actuate the brakes without pedal input. We present a system for computer control of brake and accelerator inputs on a TBW- and BBW-equipped vehicle. The system injects signals into the vehicle’s wiring harness, bypassing the pedals and obviating mechanical actuation and brake-by-dyno. The system combines feedforward control based on recorded…
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Development and demonstration of a class 6 range-extended electric vehicle for commercial pickup and delivery operation

Southwest Research Institute-Michael Kader, Cole Frazier
Cummins Inc.-John Kresse, Ke Li, Jesse Dalton
  • 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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Extend Syngas Yield through Increasing Rich Limit by Stratified Air Injection in a Single Cylinder Engine

Southwest Research Institute-Yanyu Wang, Graham Conway, D. Ryan Williams, Christopher Chadwell
  • Technical Paper
  • 2020-01-0958
To be published on 2020-04-14 by SAE International in United States
Dedicated exhaust gas recirculation (D-EGR®) concept developed by Southwest Research Institute (SwRI) has demonstrated a thermal efficiency increase on many spark-ignited engines at both low and high load conditions. The syngas (H2+CO) produced in the dedicated cylinder (D-cyl) by rich combustion helps to stabilize combustion at highly dilute conditions at low loads and mitigate knock at high loads. The dedicated cylinder with 25% EGR can typically run up to equivalence ratio of 1.4, beyond which the combustion becomes unstable. By injecting fresh air near the spark plug gap at globally rich conditions, a locally lean or near-stoichiometric mixture can be achieved, thus facilitating the ignitability of the mixture and increasing combustion stability. With more stable combustion a richer global mixture can be introduced into the D-cyl to generate higher concentrations of syngas. This in turn can further improve the engine thermal efficiency. This study investigated the possibility of extending the rich limit by stratified air injection in a single cylinder engine. A custom modified spark plug with air passage was used to realize stratified air…
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Investigation into Low-Temperature Urea-Water Solution Decomposition by Addition of Titanium-Based Isocyanic Acid Hydrolysis Catalyst and Surfactant

Southwest Research Institute-Ryan Hartley, Nolan Wright, Cary Henry
University of Texas-Zachary Tonzetich
  • Technical Paper
  • 2020-01-1316
To be published on 2020-04-14 by SAE International in United States
Mitigation of urea deposit formation and improved ammonia production at low exhaust temperatures continues to be one of the most significant challenges for current generation selective catalytic reduction (SCR) aftertreatment systems. Various technologies have been devised to alleviate these issues including: use of alternative reductant sources, and thermal treatment of the urea-water solution (UWS) pre-injection. The objective of this work was to expand the knowledge base of a potential third option, which entails chemical modification of UWS by addition of a titanium-based urea/isocyanic acid (HNCO) decomposition catalysts and/or surfactant to the fluid. Physical solid mixtures of urea with varying concentrations of ammonium titanyl oxalate (ATO), oxalic acid, and titanium dioxide (TiO2) were generated, and the differences in NH3 and CO2 produced upon thermal decomposition were quantified. It was found that addition of 2.0 mol % ATO to urea increased CO2 production by821 % and NH3 production by 96 % at temperatures ≤ 215 °C, indicating significantly enhanced hydrolysis of HNCO. Conversely, it was demonstrated that addition of oxalic acid or TiO2 to urea exhibited little…
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In-Situ Measurement of Component Efficiency in Connected and Automated Hybrid-Electric Vehicles

Southwest Research Institute-Peter Lobato, Kyle Jonson, Sankar Rengarajan, Jayant Sarlashkar
  • Technical Paper
  • 2020-01-1284
To be published on 2020-04-14 by SAE International in United States
Connected and automated driving technology is known to improve real-world vehicle efficiency by considering information about the vehicle’s environment such as traffic conditions, traffic lights or road grade. This study shows how the powertrain of a hybrid-electric vehicle realizes those efficiency benefits by developing methods to directly measure transient real-time efficiency and power losses of the vehicle’s powertrain components through chassis-dynamometer testing. This study is a follow-on to SAE Technical Paper 2019-01-0116, Test Methodology to Quantify and Analyze Energy Consumption of Connected and Automated Vehicles, to understand the sources of efficiency gains resulting from connected and automated vehicle driving. A 2017 Toyota Prius Prime was instrumented to collect power measurements throughout its powertrain and driven over a specific driving schedule on a chassis dynamometer. The same driving schedule was then modified to simulate a connected and automated vehicle driving profile, and the sources of vehicle efficiency improvements are analyzed. While conventional powertrain components typically only have two sources and sinks of power, e.g. an input and output shaft, the components of modern hybrid-electric vehicles are…
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CARB Low NOX Stage 3 Program - Aftertreatment Evaluation and Down Selection

Southwest Research Institute-Bryan Zavala, Christopher Sharp, Gary Neely, Sandesh Rao
  • Technical Paper
  • 2020-01-1402
To be published on 2020-04-14 by SAE International in United States
With the conclusion of the California Air Resources Board (CARB) Stage 1 Ultra-Low NOX program, there continues to be a commitment for identifying potential pathways to demonstrate 0.02 g/bhp-hr NOX emissions. The Stage 1 program focused on achieving the Ultra-Low NOX (ULN) levels utilizing a turbo-compound (TC) engine, which required the integration of novel catalyst technologies and a supplemental heat source. While the aftertreatment configuration provided a potential solution to meet the ULN target, a complicated approach was required to overcome challenges from low temperature exhaust. The Stage 3 program leverages a different engine architecture more representative of the broader heavy-duty industry to meet the Phase 2 GHG targets and to simplify the ULN aftertreatment solution. The following work will discuss the aftertreatment technology evaluation, down selection criteria, and the emission results of the final demonstration aftertreatment system for a heavy-duty on-highway ULN application. As part of these efforts, the demonstration system was subjected to accelerated hydrothermal and chemical aging exposure utilizing the Diesel Aftertreatment Accelerated Aging Cycles (DAAAC) protocol. The accelerated aging methodology and…
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A controls overview on achieving ultra-low NOx​

Southwest Research Institute-Sandesh Rao, Jayant Sarlashkar, Sankar Rengarajan, Christopher Sharp, Gary Neely
  • Technical Paper
  • 2020-01-1404
To be published on 2020-04-14 by SAE International in United States
The California Air Resources Board (CARB) funded Stage 3 Heavy-Duty Low NOx program focusses on evaluating different engine and after-treatment technologies to achieve 0.02g/bhp-hr of NOx emission over certification and low load cycles. This paper highlights the controls architecture of the engine and after-treatment systems and discusses the effects of various strategies implemented and tested in an engine test cell over heavy-duty drive cycles. A cylinder deactivation enabled engine was integrated with an after-treatment system consisting of a Light-Off Selective Catalytic Reduction (LO-SCR) system with a heated urea dosing system which was located close to the turbine outlet, a Catalyzed Soot Filter (CSF), and a main SCR system with single point urea dosing. Southwest Research Institute (SwRI) had developed a model-based controller for the main SCR system in the Stage 1 Low-NOx program. The chemical kinetics for the model-based controller were further tuned and implemented in this program to better simulate the reactions in the Stage 3 SCR system. Novel dosing, and ammonia storage management strategies created along with the model-based controls were critical in…
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Evaluation of an On-board, Real-time Electronic Particulate Matter Sensor Using Heavy-duty On-highway Diesel Engine Platform

Southwest Research Institute-Vinay Premnath, Imad Khalek
EmiSense Technologies LLC-Patrick Thompson, Leta Woo
  • Technical Paper
  • 2020-01-0385
To be published on 2020-04-14 by SAE International in United States
California Air Resources Board (CARB) has instituted requirements for on-board diagnostics (OBD) that makes a spark-plug sized particulate matter (PM) sensor a critical component of the OBD system to detect diesel particulate filter (DPF) failure. Current PM OBD thresholds for heavy-duty on-highway vehicles is 0.03 g/hp-hr and for light-duty vehicles (2019+ Model Year LEV III) is 17.5 mg/mile. To meet these regulations, and more stringent future regulations, real-time PM sensors offer numerous benefits over traditional accumulation type resistive sensors. The focus of this work is on the experimental evaluation of such a real-time PM sensing technology manufactured by CoorsTek LLC. A 2011 model year on-highway heavy-duty diesel engine fitted with diesel oxidation catalyst/diesel particulate filter/selective catalytic reducer/ammonia oxidation catalyst (DOC/DPF/SCR/AMOX) was used for the evaluation program. Sensors were tested at an emission level of ~ 0.02 g/hp-hr using five repeats each of Federal Test Procedure (FTP), Non-road transient cycle (NRTC), world harmonized transient cycle (WHTC) and ramped modal cycle (RMC) drive cycles. Exhaust emission levels were tuned using a bypass DOC flow path fitted in…