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Semi-Volatile Organic Compounds from a Combined Dual Port Injection/Direct-Injection Technology Light-Duty Gasoline Vehicle

Southwest Research Institute-Robert Fanick, Svitlana Kroll
  • Technical Paper
  • 2019-24-0051
Published 2019-09-09 by SAE International in United States
Gasoline direct injection (GDI) has changed the exhaust composition in comparison with the older port fuel injection (PFI) systems. More recently, light-duty vehicle engine manufactures have combined these two technologies to take advantage of the knock benefits and fuel economy of GDI with the low particulate emission of PFI. These dual injection strategy engines have made a change in the combustion emission composition produced by these engines. Understanding the impact of these changes is essential for automotive companies and aftertreatment developers.A novel sampling system was designed to sample the exhaust generated by a dual injection strategy gasoline vehicle using the United States Federal Test Procedure (FTP). This sampling system was capable of measuring the regulated emissions as well as collecting the entire exhaust from the vehicle for measuring unregulated emissions. For this study, the unregulated emissions included hydrocarbon speciation and semi-volatile organic compounds (SVOC) in the form of polycyclic aromatic hydrocarbons (PAH), nitro-polycyclic aromatic hydrocarbons (NPAH), and oxygenated PAH (Oxy PAH). This novel sampling system allowed the quantification of the particulate-phase SVOC as part of…
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Deposit Reduction in SCR Aftertreatment Systems by Addition of Ti-Based Coordination Complex to UWS

Southwest Research Institute-Cary Henry, Scott Eakle
University of Texas-San Antonio-Ryan Hartley, Zachary Tonzetich
Published 2019-04-02 by SAE International in United States
Formation of urea-derived deposits in selective catalytic reduction (SCR) aftertreatment systems continues to be problematic at temperatures at and below 215 °C. Several consequences of deposit formation include: NOx and NH3 slip, exhaust flow maldistribution, increased engine backpressure, and corrosion of aftertreatment components. Numerous methods have been developed to reduce deposit formation, but to date, there has been no solution for continuous low-temperature dosing of Urea-Water Solution (UWS). This manuscript presents a novel methodology for reducing low-temperature deposit formation in SCR aftertreatment systems. The methodology described herein involves incorporation and dissolution of an HNCO hydrolysis catalyst directly into the UWS. HNCO is a transient species formed by the thermolysis of urea upon injection of UWS into the aftertreatment system. Ideally HNCO undergoes hydrolysis to form NH3 and CO2, but under certain conditions HNCO may polymerize or react with other constituents in the exhaust. Reaction of HNCO with species other than water generally results in the formation of deposits in the aftertreatment system. Addition of an HNCO hydrolysis catalyst directly into the UWS provides maximum contact…
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Combined Benefits of Variable Valve Actuation and Low-Pressure EGR on SI Engine Efficiency Part 1: Part Load

Southwest Research Institute-Yanyu Wang, Graham Conway, Chris Chadwell
Published 2019-04-02 by SAE International in United States
Modern spark ignited engines face multiple barriers to achieving higher thermal efficiency. This study investigated the potential of utilizing both continuously variable valve actuation (VVA) and low-pressure cooled exhaust gas recirculation (EGR) to improve engine thermal efficiency at part-load conditions. Six speed / load points were investigated on a 1.6 L turbocharged gasoline direct injection engine. A design of experiment (DoE) approach using the Box-Behnken surface response model was conducted. The DoE results revealed different brake specific fuel consumption (BSFC) responses to the valve phasing and the intake valve lift at different operating conditions. Further engine testing was carried out at each speed / load point to confirm the engine efficiency and combustion performance when targeting different valvetrain controls and EGR strategies. The results indicated that utilizing the VVA system could always reduce BSFC at the studied operating conditions. The BSFC reduction was attributed to reduced pumping and incomplete combustion losses. The reduction in losses was attributed to optimizing the amount of hot trapped residuals compared with the fixed valve configuration, and load control through…
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Fuel Reforming and Catalyst Deactivation Investigated in Real Exhaust Environment

Raphael Gukelberger
Southwest Research Institute-Robert Henderson, Cary Henry
Published 2019-04-02 by SAE International in United States
Increased in-cylinder hydrogen levels have been shown to improve burn durations, combustion stability, HC emissions and knock resistance which can directly translate into enhanced engine efficiency. External fuel reformation can also be used to increase the hydrogen yield. During the High-Efficiency, Dilute Gasoline Engine (HEDGE) consortium at Southwest Research Institute (SwRI), the potential of increased hydrogen production in a dedicated-exhaust gas recirculation (D-EGR) engine was evaluated exploiting the water gas shift (WGS) and steam reformation (SR) reactions. It was found that neither approach could produce sustained hydrogen enrichment in a real exhaust environment, even while utilizing a lean-rich switching regeneration strategy. Platinum group metal (PGM) and Ni WGS catalysts were tested with a focus on hydrogen production and catalyst durability. Although 4% additional hydrogen was initially produced in the EGR stream, leading to improvements in the coefficient of variation (CoV) and brake specific fuel consumption (BSFC), catalyst activity decreased within a few hours regardless of the regeneration strategy employed. With an SR catalyst, a small amount of hydrogen was produced in the EGR stream via…
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Benchmarking a 2018 Toyota Camry 2.5-Liter Atkinson Cycle Engine with Cooled-EGR

SAE International Journal of Advances and Current Practices in Mobility

Southwest Research Institute-Josh Alden
US Environmental Protection Agency-John Kargul, Mark Stuhldreher, Daniel Barba, Charles Schenk, Stanislav Bohac, Joseph McDonald, Paul Dekraker
  • Journal Article
  • 2019-01-0249
Published 2019-04-02 by SAE International in United States
As part of the U.S. Environmental Protection Agency’s (EPA’s) continuing assessment of advanced light-duty automotive technologies in support of regulatory and compliance programs, a 2018 Toyota Camry A25A-FKS 4-cylinder, 2.5-liter, naturally aspirated, Atkinson Cycle engine with cooled exhaust gas recirculation (cEGR) was benchmarked. The engine was tested on an engine dynamometer with and without its 8-speed automatic transmission, and with the engine wiring harness tethered to a complete vehicle parked outside of the test cell. Engine and transmission torque, fuel flow, key engine temperatures and pressures, onboard diagnostics (OBD) data, and Controller Area Network (CAN) bus data were recorded. This paper documents the test results under idle, low, medium, and high load engine operation. Motoring torque, wide open throttle (WOT) torque and fuel consumption are measured during transient operation using both EPA Tier 2 and Tier 3 test fuels. The design and performance of this 2018 2.5-liter engine is described and compared to Toyota’s published data and to EPA’s previous projections of the efficiency of an Atkinson Cycle engine with cEGR. The Brake Thermal Efficiency…
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Evaluation of Gasoline Additive Packages to Assess Their Ability to Clean Up Intake Valve Deposits in Automotive Engines

Southwest Research Institute-Matthew Hinojosa, Brent Shoffner
Shell Global Solutions (US) Inc.-Vivek Raja Raj Mohan, Edward Nelson, Jannik Reitz, Jennifer Kensler, Varun Gauba
Published 2019-04-02 by SAE International in United States
The majority of passenger car and light-duty trucks, especially in North America, operate using port-fuel injection (PFI) engines. In PFI engines, the fuel is injected onto the intake valves and then pulled into the combustion chamber during the intake stroke. Components of the fuel are unstable in this environment and form deposits on the upstream face of the intake valve. These deposits have been found to affect a vehicle’s drivability, emissions and engine performance. Therefore, it is critical for the gasoline to be blended with additives containing detergents capable of removing the harmful intake valve deposits (IVDs).Established standards are available to measure the propensity of IVD formation, for example the ASTM D6201 engine test and ASTM D5500 vehicle test. However, rigorous testing conducted in a modern fleet of vehicles in a statistically robust design can provide greater insight into the actual performance of modern PFI engines with available gasoline additive packages. In this study, an optimized mileage accumulation protocol was used to assess the performance of new experimental gasoline additive packages in removing the IVDs…
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Development of a Natural Gas Engine with Diesel Engine-like Efficiency Using Computational Fluid Dynamics

Southwest Research Institute-Ahmed Abdul Moiz, Zainal Abidin, Robert Mitchell, Michael Kocsis
Published 2019-04-02 by SAE International in United States
Present day natural gas engines have a significant efficiency disadvantage but benefit with low carbon-dioxide emissions and cheap three-way catalysis aftertreatment. The aim of this work is to improve the efficiency of a natural gas engine on par with a diesel engine. A Cummins-Westport ISX12-G (diesel) engine is used for the study. A baseline model is validated in three-dimensional Computational Fluid Dynamics (CFD). The challenge of this project is adapting the diesel engine for the natural gas fuel, so that the increased squish area of the diesel engine piston can be used to accomplish faster natural gas burn rates. A further increase efficiency is achieved by switching to D-EGR technology. D-EGR is a concept where one or more cylinders are run with excess fueling and its exhaust stream, containing H2 and CO, is cooled and fed into the intake stream. With D-EGR although there is an in-cylinder presence of a reactive H2-CO reformate, there is also higher levels of dilution. A new piston was designed that can match the high squish burn rates with not…
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Predictive GT-Power Simulation for VNT Matching to EIVC Strategy on a 1.6 L Turbocharged GDI Engine

Southwest Research Institute-Yanyu Wang, Graham Conway
Environmental Protection Agency-Joseph McDonald
Published 2019-04-02 by SAE International in United States
The use of early intake valve closing (EIVC) can lead to improvements in spark-ignition engine efficiency. One of the greatest barriers facing adoption of EIVC for high power-density applications is the challenge of boosting as EIVC strategies reduce volumetric efficiency. Turbochargers with variable nozzle turbines (VNT) have recently been developed for gasoline applications operating at high exhaust gas temperatures. The use of a single VNT as a boost device may provide a lower-cost option compared to two-stage boosting systems or 48 V electronic boost devices for some EIVC applications. A predictive model was created based on engine testing results from a 1.6 L turbocharged gasoline direct injection engine [1]. The model was tuned so that it predicted burn-rates and end-gas knock over an engine operating map with varying speeds, loads, compression ratios and fuel types. Using the model, an assessment of VNT performance was implemented using compressor and turbine maps made available from Garrett Motion, Inc. Results show that the single VNT device supports mild EIVC across the operating map while maintaining acceptable full-load performance…
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Effects of Dual Port Injection and Direct-Injection Technology on Combustion Emissions from Light-Duty Gasoline Vehicles

Southwest Research Institute-Robert Fanick, Svitlana Kroll, Andre Swarts, Shraddha Quarderer
Published 2019-04-02 by SAE International in United States
Dual injection fuel systems combine the knock and fuel economy benefits of gasoline direct injection (GDI) technology with the lower particulate emissions of port fuel injection (PFI) systems. For many years, this technology was limited to smaller-volume, high-end, vehicle models, but these technologies are now becoming main stream. The combination of two fuel injection systems has an impact on the combustion emission composition as well as the consistency of control strategy and emissions. Understanding the impact of these changes is essential for fuel and fuel additive companies, automotive companies, and aftertreatment developers.This paper describes the effects of dual injection technology on both regulated and non-regulated combustion emissions from a 2018 Toyota Camry during several cold-start, 4-bag United States Federal Test Procedure (FTP) cycle. Data from the Controller Area Network (CAN) was acquired through the on-board diagnostic (OBD) connector to determine the injection strategy for a 2018 Toyota Camry with a dual injection fuel system. The regulated and non-regulated emissions were also compared to 2017 Toyota Camry emission results with PFI. These vehicles were tested both…
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An Exploratory Look at an Aggressive Miller Cycle for High BMEP Heavy-Duty Diesel Engines

Southwest Research Institute-Kevin L. Hoag
Published 2019-04-02 by SAE International in United States
Through aggressive application of the Miller Cycle, using two-stage turbocharging, medium speed diesel marine and stationary power engines are demonstrating over 30 bar rated power BMEP, and over 50 percent brake thermal efficiency. The objective of this work was to use engine cycle simulation to assess the degree to which the aggressive application of the Miller Cycle could be scaled to displacements and speeds more typical of medium and heavy truck engines. A 9.2 liter six-cylinder diesel engine was modeled. Without increasing the peak cylinder pressure, improved efficiency and increased BMEP was demonstrated. The level of improvement was highly dependent on turbocharger efficiency - perhaps the most difficult parameter to scale from the larger engines. At 1600 rpm, and a combined turbocharger efficiency of 61 percent, the baseline BMEP of 24 bar was increased to over 26 bar, with a two percent fuel consumption improvement. As turbocharger combined efficiency increased, to over 75 percent as seen in large, medium speed engines, over 29 bar BMEP was achieved, with over six percent fuel consumption improvement. Similar…
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