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Technical Paper

A Comprehensive CFD-FEA Conjugate Heat Transfer Analysis for Diesel and Gasoline Engines

2019-04-02
2019-01-0212
As the efforts to push capabilities of current engine hardware to their durability limits increases, more accurate and reliable analysis is necessary to ensure that designs are robust. This paper evaluates a method of Conjugate Heat Transfer (CHT) analysis for a gasoline and a diesel engine that combines combustion Computational Fluid Dynamics (CFD), engine Finite Element Analysis (FEA), and cooling jacket CFD with the goal of obtaining more accurate temperature distribution and heat loss predictions in an engine compared to standard de-coupled CFD and FEA analysis methods. This novel CHT technique was successfully applied to a 2.5 liter GM LHU gasoline engine at 3000 rpm and a 15.0 liter Cummins ISX heavy duty diesel engine operating at 1250 rpm. Combustion CFD simulations results for the gasoline and diesel engines are validated with the experimental data for cylinder pressure and heat release rate.
Technical Paper

Particle Emissions from Gasoline Direct Injection Engines during Engine Start-Up (Cranking)

2019-04-02
2019-01-1182
Engine start-up (cranking) can be an important source of particle emissions from vehicles. With the penetration of GDI vehicles in the global vehicle fleet, it is important to analyze and understand the contribution of start-up particle emissions from GDI vehicles, and the potential effects of fuel properties on that process. In this work, chassis dynamometer based investigation on the effect of several gasoline fuels (commercial and blended) on both, naturally aspirated and turbocharged GDI vehicles were conducted to understand the importance of engine start up, in particular, cranking. 10 commercially available gasoline fuels were tested on a naturally aspirated 2010 model year GDI vehicle, 3 among these commercially available fuels were tested on another 2009 model year turbocharged GDI vehicle, and 8 blended gasoline fuels were tested on 12 other GDI vehicles (7 turbocharged and 5 naturally aspirated) ranging in model years 2011-2015.
Technical Paper

Effects of Dual Port Injection and Direct-Injection Technology on Combustion Emissions from Light-Duty Gasoline Vehicles

2019-04-02
2019-01-0999
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.
Journal Article

Benchmarking a 2018 Toyota Camry 2.5-Liter Atkinson Cycle Engine with Cooled-EGR

2019-04-02
2019-01-0249
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.
Technical Paper

Review of the Computer Science and Engineering Solutions for Model Sharing and Model Co-Simulation

2019-03-19
2019-01-1352
The process of developing, parameterizing, validating, and maintaining models occurs within a wide variety of tools, and requires significant time and resources. To maximize model utilization, models are often shared between various toolsets and experts. One common example is sharing aircraft engine models with airframers. The functionality of a given model may be utilized and shared with a secondary model, or multiple models may run collaboratively through co-simulation. There are many technical challenges associated with model sharing and co-simulation. For example, data communication between models and tools must be accurate and reliable, and the model usage must be well-documented and perspicuous for a user. This requires clear communication and understanding between computer scientists and engineers. Most often, models are developed by engineers, whereas the tools used to share the models are developed by computer scientists.
Technical Paper

Investigation of an Advanced Combustion System for Stoichiometric Diesel to Reduce Soot Emissions

2019-01-15
2019-01-0023
Diesel engines are facing increased competition from gasoline engines in the light-duty and small non-road segments, primarily due to the high relative cost of emissions control systems for lean-burn diesel engines. Advancements in gasoline engine technology have decreased the operating cost advantage of diesels and the relatively high initial-cost disadvantage is now too large to sustain a strong business position. SwRI has focused several years of research efforts toward enabling diesel engine combustion systems to operate at stoichiometric conditions, which allows the application of a low-cost three-way catalyst emission control system which has been well developed for gasoline spark-ignited engines. One of the main barriers of this combustion concept is the result of high smoke emissions from poor fuel/air mixing.
Technical Paper

On-Road Monitoring of Low Speed Pre-Ignition

2018-09-10
2018-01-1676
To meet increasingly stringent emissions and fuel economy regulations, many Original Equipment Manufacturers (OEMs) have recently developed and deployed small, high power density engines. Turbocharging, coupled with gasoline direct injection (GDI) has enabled a rapid engine downsizing trend. While these turbocharged GDI (TGDI) engines have indeed allowed for better fuel economy in many light duty vehicles, TGDI technology has also led to some unintended consequences. The most notable of these is an abnormal combustion phenomenon known as low speed pre-ignition (LSPI). LSPI is an uncontrolled combustion event that takes place prior to spark ignition, often resulting in knock, and has been known to cause catastrophic engine damage. LSPI propensity depends on a number of factors including engine design, calibration, fuel properties and engine oil formulation. Several engine tests have been developed within the industry to better understand the phenomenon of LSPI.
Technical Paper

Relationship among Various Particle Characterization Metrics Using GDI Engine Based Light-Duty Vehicles

2018-04-03
2018-01-0353
In recent years, gasoline direct injection (GDI) engines have been widely used by manufacturers in light-duty to meet stringent fuel economy and emissions standards. This study focuses on the relationship between various particle metrics such as number, size, surface area and mass of dilute exhaust particles from 12 different light-duty vehicles equipped with GDI engines. The campaign included the measurement of total particulate matter (PM) using Title 40 CFR Part 1066 compliant filter measurement, soot mass using photo-acoustics based analyzer, organic carbon (OC) & elemental carbon (EC) mass using thermo-optical analysis of quartz filter samples, solid particle number using European Union Regulation No. 49 compliant number system and solid particle size/number using an electrical mobility based size spectrometer.
Technical Paper

In-Situ Measurement of Holistic Powertrain Efficiency in Vehicles

2018-04-03
2018-01-0324
Conventional methods for determining automotive powertrain efficiency include (1) component-level testing, such as engine dynamometer, transmission stand or axle stand testing, (2) simulations based on component level test data and (3) vehicle-level testing, such as chassis dynamometer or on-road testing. This paper focuses on vehicle-level testing to show where energy is lost throughout a complete vehicle powertrain. This approach captures all physical effects of a vehicle driving in real-world conditions, including torque converter lockup strategies, transmission shifting, engine control strategies and inherent mechanical efficiency of the components. A modern rear-wheel drive light duty pickup truck was instrumented and tested on a chassis dynamometer. Power was measured at the engine crankshaft output, the rear driveshaft and at the dynamometer.
Technical Paper

Selective Interrupt and Control: An Open ECU Alternative

2018-04-03
2018-01-0127
To enable the evaluation of off-calibration powertrain operation, a selective interrupt and control (SIC) test capability was developed as part of an EPA evaluation of a 1.6 L EcoBoost® engine. A control and data acquisition device sits between the stock powertrain controller and the engine; the device selectively passes through or modifies control signals while also simulating feedback signals. This paper describes the development process of SIC that enabled a test engineer to command off-calibration setpoints for intake and exhaust cam phasing as well as ignition timing without the need for an open ECU duplicating the stock calibration. Results are presented demonstrating the impact of ignition timing and cam phasing on engine efficiency. When coupled with combustion analysis and crank-domain data acquisition, this test configuration provides a complete picture of powertrain performance.
Technical Paper

In-Situ Measurement of Transmission Efficiency in Vehicles

2017-03-28
2017-01-1095
SAE Recommended Practice J1540 [1] specifies test procedures to map transmission efficiency and parasitic losses in a manual transmission. The procedure comprises two parts. The first compares input and output torque over a range of speed to determine efficiency. The second measures parasitic losses at zero input torque over a range of speed. As specified in J1540, efficiency of transmissions is routinely measured on a test-stand under steady torque and speed [2] [3]. While such testing is useful to compare different transmissions, it is unclear whether the “in-use” efficiency of a given transmission is the same as that measured on the stand. A vehicular transmission is usually mated to a reciprocating combustion engine producing significant torque and speed fluctuations at the crankshaft. It is thus a valid question whether the efficiency under such pulsating conditions is the same as that under steady conditions.
Technical Paper

Dilute Combustion Assessment in Large Bore, Low Speed Engines

2017-03-28
2017-01-0580
The promising D-EGR gasoline engine results achieved in the test cell, and then in a vehicle demonstration have led to exploration of further possible applications. A study has been conducted to explore the use of D-EGR gasoline engines as a lower cost replacement for medium duty diesel engines in trucks and construction equipment. However, medium duty diesel engines have larger displacement, and tend to require high torque at lower engine speeds than their automobile counterparts. Transmission and final drive gearing can be utilized to operate the engine at higher speeds, but this penalizes life-to-overhaul. It is therefore important to ensure that D-EGR combustion system performance can be maintained with a larger cylinder bore, and with high specific output at relatively low engine speeds.
Journal Article

Cycle-Average Heavy-Duty Engine Test Procedure for Full Vehicle Certification - Numerical Algorithms for Interpreting Cycle-Average Fuel Maps

2016-09-27
2016-01-8018
In June of 2015, the Environmental Protection Agency and the National Highway Traffic Safety Administration issued a Notice of Proposed Rulemaking to further reduce greenhouse gas emissions and improve the fuel efficiency of medium- and heavy-duty vehicles. The agencies proposed that vehicle manufacturers would certify vehicles to the standards by using the agencies’ Greenhouse Gas Emission Model (GEM). The agencies also proposed a steady-state engine test procedure for generating GEM inputs to represent the vehicle’s engine performance. In the proposal the agencies also requested comment on an alternative engine test procedure, the details of which were published in two separate 2015 SAE Technical Papers [1, 2]. As an alternative to the proposed steady-state engine test procedure, these papers presented a cycle-average test procedure.
Journal Article

Automated Driving Impediments

2016-09-27
2016-01-8007
Since the turn of the millennium, automated vehicle technology has matured at an exponential rate, evolving from research largely funded and motivated by military and agricultural needs to a near-production market focused on everyday driving on public roads. Research and development has been conducted by a variety of entities ranging from universities to automotive manufacturers to technology firms demonstrating capabilities in both highway and urban environments. While this technology continues to show promise, corner cases, or situations outside the average driving environment, have emerged highlighting scenarios that impede the realization of full automation anywhere, anytime. This paper will review several of these corner cases and research deficiencies that need to be addressed for automated driving systems to be broadly deployed and trusted.
Technical Paper

Evaluation of Cold Start Technologies on a 3L Diesel Engine

2016-04-05
2016-01-0823
Increasingly stringent emissions regulations require that modern diesel aftertreatment systems must warm up and begin controlling emissions shortly after startup. While several new aftertreatment technologies have been introduced that focus on lowering the aftertreatment activation temperature, the engine system still needs to provide thermal energy to the exhaust for cold start. A study was conducted to evaluate several engine technologies that focus on improving the thermal energy that the engine system provides to the aftertreatment system while minimizing the impact on fuel economy and emissions. Studies were conducted on a modern common rail 3L diesel engine with a custom dual loop EGR system. The engine was calibrated for low engine-out NOx using various combustion strategies depending on the speed/load operating condition.
Technical Paper

Technical Approach to Increasing Fuel Economy Test Precision with Light Duty Vehicles on a Chassis Dynamometer

2016-04-05
2016-01-0907
In 2012, NHTSA and EPA extended Corporate Average Fuel Economy (CAFE) standards for light duty vehicles through the 2025 model year. The new standards require passenger cars to achieve an average of five percent annual improvement in fuel economy and light trucks to achieve three percent annual improvement. This regulatory requirement to improve fuel economy is driving research and development into fuel-saving technologies. A large portion of the current research is focused on incremental improvements in fuel economy through technologies such as new lubricant formulations. While these technologies typically yield less than two percent improvement, the gains are extremely significant and will play an increasing role in the overall effort to improve fuel economy. The ability to measure small, but statistically significant, changes in vehicle fuel economy is vital to the development of new technologies.
Technical Paper

Detailed Characterization of Criteria Pollutant Emissions from D-EGR® Light Duty Vehicle

2016-04-05
2016-01-1006
In this study, the criteria pollutant emissions from a light duty vehicle equipped with Dedicated EGR® technology were compared with emissions from an identical production GDI vehicle without externally cooled EGR. In addition to the comparison of criteria pollutant mass emissions, an analysis of the gaseous and particulate chemistry was conducted to understand how the change in combustion system affects the optimal aftertreatment control system. Hydrocarbon emissions from the vehicle were analyzed usin g a variety of methods to quantify over 200 compounds ranging in HC chain length from C1 to C12. The particulate emissions were also characterized to quantify particulate mass and number. Gaseous and particulate emissions were sampled and analyzed from both vehicles operating on the FTP-75, HWFET, US06, and WLTP drive cycles at the engine outlet location.
Technical Paper

Comparison of Hydrocarbon Measurement with FTIR and FID in a Dual Fuel Locomotive Engine

2016-04-05
2016-01-0978
Exhaust emissions of non-methane hydrocarbon (NMHC) and methane were measured from a Tier 3 dual-fuel demonstration locomotive running diesel-natural gas blend. Measurements were performed with the typical flame ionization detector (FID) method in accordance with EPA CFR Title 40 Part 1065 and with an alternative Fourier-Transform Infrared (FTIR) Spectroscopy method. Measurements were performed with and without oxidation catalyst exhaust aftertreatment. FTIR may have potential for improved accuracy over the FID when NMHC is dominated by light hydrocarbons. In the dual fuel tests, the FTIR measurement was 1-4% higher than the FID measurement of. NMHC results between the two methods differed considerably, in some cases reporting concentrations as much as four times those of the FID. However, in comparing these data it is important to note that the FTIR method has several advantages over the FID method, so the differences do not necessarily represent error in the FTIR.
Technical Paper

Parametric Study and Secondary Circuit Model Calibration Using Spark Calorimeter Testing

2015-04-14
2015-01-0778
The presented work describes how spark calorimeter testing was used for parametric study and secondary circuit model calibration. Tests were conducted at different pressures, sparkplug gaps and supplied primary energies. The conversion efficiency increases and the spark duration decreases when the gas pressure or the sparkplug gap size is increased. Both gas pressure and sparkplug gas size increase the positive column voltage which represents part of the electrical energy delivered to the gas. The opposite direction occurs when the supplied primary energy is increased. The testing results were then used to calibrate the secondary circuit model which consisted of the sparkplug, the sparkplug gap and the secondary wiring. A step-by-step method was used to calibrate the three constants of the model to match the calculated delivered energy with test data during arc / glow phase.
Technical Paper

Software Defined Radio and Security in the Automotive Domain

2015-04-14
2015-01-0203
Several wireless systems such as Dedicated Short Range Communication (DSRC), cellular, Wi-Fi, Bluetooth, and the Tire Pressure Monitoring System (TPMS) can be found on modern vehicles. In the future, Software Defined Radio (SDR) technology could be integrated into automobiles to increase the efficiency and adaptability of wireless communications systems. SDR is also a powerful tool for designing and testing new communications protocols. However there are also some security considerations associated with SDR. This paper will review some advantages of using SDR technology in the automotive domain as well as potential security issues. The authors are currently conducting research into the use of SDR technology to model wireless systems and investigate security threats in modern vehicular systems.
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