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Diminishing Benefits of Federal Reformulated Gasoline (RFG) Compared to Conventional Gasoline (CG)

Denver University, USA-Gary Bishop
Desert Research Institute, USA-Steven Kent Hoekman, Amber Leland
  • Journal Article
  • 04-12-01-0001
To be published on 2019-12-20 by SAE International in United States
The Federal reformulated gasoline (RFG) program originated with the 1990 Clean Air Act Amendments to address high ozone and air toxics levels in major urban areas. These areas include portions of 17 states and represent approximately 30% of the total U.S. gasoline volume. Initially, formulation changes were limited to addition of oxygen and reductions in benzene and fuel Reid vapor pressure (RVP) levels. These reformulations were intended to meet minimum emissions reduction targets for volatile organic compounds (VOCs), air toxics, and oxides of nitrogen (NOx) when compared to a 1990 baseline gasoline in a “1990’s technology” vehicle fleet. The United States Environmental Protection Agency (U.S. EPA) developed two computational models, the Simple Model in 1995 and the Complex Model in 1998, for use in demonstrating compliance with the regulations. This article reviews the derivation and evolution of the RFG program. Initially, RFG’s emissions reduction benefits compared to conventional gasoline (CG) resulted primarily from differences in fuel sulfur levels, benzene content, and RVP. However, due to other regulatory changes over the past two decades, the compositions…
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Methods of Pegging Cylinder Pressure to Maximize Data Quality

Michigan Tech APS LABS-Jeremy Worm
Michigan Technological Univ-Darrell Robinette
  • Technical Paper
  • 2019-01-0721
To be published on 2019-04-02 by SAE International in United States
Engine cylinder pressure measured with piezo-electric pressure transducers must be referenced or pegged to a known pressure at some point in the engine cycle. Traditionally, the pressure has been pegged to the pressure in the intake manifold plenum at Bottom Dead Center (BDC) at the end of the intake stroke. However, an error in pegging induces an error in the cylinder pressure trace, which has an adverse effect on the entire combustion analysis. This research is focused on assessing the pegging error for several pegging methods across a wide range of engine operating conditions, and ultimately determining best practices to minimize error in pegging and its propagation to calculated combustion metrics. The study was conducted through 1D simulations run in the commercially available GT-Power. The points studied included variations of speed, load, intake runner length and intake valve timing (including Late Intake Valve Closing (LIVC) and Early Intake Valve Closing (EIVC)). Five different pegging locations were compared (intake manifold plenum, intake port, intake valve, exhaust valve, and exhaust manifold runner). For each of the five…

A Quasi-Dimensional Model of Pre-Chamber Spark-Ignition Engines

FEV Engine Technology-Knut Habermann
University of Naples-Fabio Bozza, Vincenzo De Bellis, Daniela Tufano, Enrica Malfi
  • Technical Paper
  • 2019-01-0470
To be published on 2019-04-02 by SAE International in United States
Increasingly stringent legislations are inducing the car manufacturers to investigate innovative solutions to improve the vehicle fuel economy. Some of them act on the vehicle/engine interaction, such as the powertrain electrification, while other techniques directly affect the engine thermal efficiency. Among them, concerning the spark-ignition engines, a lean combustion showed the potential to improve the fuel consumption. This approach, on the other hand, causes some drawbacks, such as a combustion stability worsening and the impossibility for the TWC to optimally operate. A pre-chamber ignition system could represent an interesting solution to overcome the above issues. Especially in the case of an active system, a high fuel-air mixture ignitability, and an adequate combustion speed can be obtained even with a very lean mixture. In this work, a research single-cylinder SI engine equipped with an active pre-chamber is analyzed. A conventional gasoline fuel is injected in the main chamber while the pre-chamber is fed with CNG. In a first stage, an experimental campaign is carried out under various operating conditions, at various speeds, spark timings and air-fuel…

Heavy-duty aerodynamic testing for CO2 certification: A methodology comparison

Intl. Council on Clean Transportation-J. Felipe Rodriguez, Oscar Delgado
University of Technology Graz-Martin Rexeis, Martin Röck
  • Technical Paper
  • 2019-01-0649
To be published on 2019-04-02 by SAE International in United States
Air drag testing is a key component of the CO2 certification schemes for heavy-duty vehicles around the world. This paper presents and compares the regulatory approaches for measuring the air drag coefficient of heavy-duty vehicles in Europe, which uses a constant-speed test, and in the United States and Canada, which use a coastdown test. Two European trucks and one North American truck were tested using the constant-speed and coastdown methods. When corrected to zero yaw angle, a difference of over 10% was observed in the measured drag coefficients from the US coastdown procedure and the EU constant-speed test. The differences in the measured air drag coefficient can be attributed to the data post-processing required by each methodology, the assumptions in the speed-dependence of the tire rolling resistance, unaccounted frictional losses in the differential axle and transmission, as well as the behavior of the automated manual transmission during the coastdown run.

Improved Approach for Analytically Derived CO2 Prediction of Medium Duty Chassis Certified Vehicles

Ford Motor Company-Mrudula Orpe, Thomas Megli, Patrick Phlips, William Ruona, Donnell Washington II
  • Technical Paper
  • 2019-01-0311
To be published on 2019-04-02 by SAE International in United States
Medium duty vehicles come in many design variations, which makes testing them all for CO2 impractical. As a result there are multiple ways of reporting CO2 emissions. Actual tests may be performed, data substitution may be used, or CO2 values may be estimated using an analytical correction. The correction accounts for variations in road load force coefficients (f0, f1, f2), weight, and axle ratio. The Code of Federal Regulations defines this Analytically Derived CO2 equation (ADC) using a limited set of historical data. The current ADC equation prediction error of ~120 g/mile is about 4 to 5 times higher than test-to-test variability, which has restricted its use. An improved method is desired to (1) reduce testing expense and complexity, and (2) provide a better CO2 estimate. Previous work on light duty vehicles has demonstrated a physical linear relation between vehicle fuel consumption, powertrain properties and total vehicle work [SAE 2018-01-0322]. This functional form is used to improve the accuracy of the ADC equation, and avoids collinearity and non-orthogonality of the predictor variables. The form also…

Experimental investigations on the influence of valve timing and multi-pulse injection on GCAI Combustion

Indian Institute of Technology Madras-Jensen Samuel, Santhosh Mithun, Kasinath Panda, A Ramesh
MSCE, RWTH Aachen University-Maximilian Wick, Jakob Andert
  • Technical Paper
  • 2019-01-0967
To be published on 2019-04-02 by SAE International in United States
Gasoline Compressed Auto-Ignition (GCAI) technology, which can be categorized under Homogeneous Charge Compression Ignition (HCCI), is a low-temperature combustion system with promising benefits such as ultra-low in-cylinder NOx emissions and reduced brake-specific fuel consumption, which are the critical parameters in any modern engine. Since this technology is based on uncontrolled auto-ignition of a premixed charge, it is very sensitive to any change in boundary conditions during engine operation. Adopting real time valve timing and fuel-injection strategies can enable improved control over GCAI combustion. This work discusses the outcome of collaborative experimental research by the partnering institutes in this direction. Experiments were performed in a single cylinder GCAI engine with variable valve timing and Gasoline Direct Injection (GDI) at constant indicated mean effective pressure (IMEP). In the first phase, intake and exhaust valve timing sweeps were investigated. It was found that the Intake Valve Closing (IVC) timing and Exhaust Valve Closing (EVC) timing have a dominant influence on combustion, performance and emission parameters. Retarding the IVC timing to a certain extent increased the mass of air…

Evaluation of Emissions from Light Duty Trucks with and without the Use of a Gasoline Particulate Filter

Environment and Climate Change Canada-Fadi Araji, Jonathan Stokes
  • Technical Paper
  • 2019-01-0971
To be published on 2019-04-02 by SAE International in United States
The goal of this study was to investigate the emission impacts of replacing the OEM three way catalyst on light duty trucks using various, commercially available, gasoline particulate filter (GPF) configurations. The three test vehicles were; a Port Fuel Injection (PFI) PFI_1 and two Gasoline Direct Injection (GDI) GDI_1 and GDI_2. The testing of these vehicles was conducted on a chassis dynamometer in a controlled test cell environment at two temperatures (25 °C and -7 °C) using the Federal Test Procedure (FTP-75) and the US06 test procedure. All three vehicles were tested in stock OEM configuration followed by testing PFI_1 and GDI_1 with a non-catalyzed GPF and GDI_2 with a catalyzed GPF. GDI_2 was also tested on-road using a portable emissions measurement system (PEMS) with and without the use of the catalyzed GPF. Results for the non-catalyzed GPF configuration on PFI_1 and GDI_1 showed a decrease in Total Particulate Matter (TPM) at both standard and cold temperatures, with the biggest decrease being 89.3% for GDI_1 during the FTP-75 at 25 °C. An increase in NOx…

The Physical and Chemical Effects of Fuel on Gasoline Compression Ignition

King Abdullah Univ of Science & Tech-Ponnya Hlaing, Abdullah S. AlRamadan, Yanzhao An, Bengt Johansson
Saudi Aramco-R. Vallinayagam, Jaeheon Sim, Junseok Chang
  • Technical Paper
  • 2019-01-1150
To be published on 2019-04-02 by SAE International in United States
In the engine community, gasoline compression ignition (GCI) engines are at the forefront of research and efforts are being taken to commercialize an optimized GCI engine in the near future. GCI engines are operated typically at Partially Premixed Combustion (PPC) mode as it offers better control of combustion with improved combustion stability. While the transition in combustion homogeneity from convectional Compression Ignition (CI) to Homogenized Charge Compression Ignition (HCCI) combustion via PPC has been compressively investigated, the physical and chemical effects of fuel on GCI are rarely reported at different combustion modes. Therefore, in this study, the effect of physical and chemical properties of fuels on GCI is investigated. In-order to investigate the reported problem, low octane gasoline fuels with same RON = 70 but different physical properties and sensitivity (S) are chosen. Fuels with comparable sensitivity and RON are chosen to study the impact of physical properties on GCI. On the other hand, by keeping the same RON and physical properties, the effect of sensitivity on GCI is investigated. In this regard, three test…


Bauman Moscow Technical University-Revaz Kavtaradze
Institute of Machine Mechanics-Tamaz Natriashvili
  • Technical Paper
  • 2019-01-0541
To be published on 2019-04-02 by SAE International in United States
The diesel engine with direct injection of hydrogen gas has clear advantages over the hydrogen engine with forced ignition of a hydrogen-air mixture. Despite of this, the concept of hydrogen-diesel engine has not investigated until now. In the paper, a detailed study of the working process of hydrogen-diesel engine carried out for the first time. Based on the results of the experimental studies and mathematical modeling, it has established that the behavior of thermophysical processes in the combustion chamber of hydrogen-diesel engine, in a number of cases, differs fundamentally from the processes that take place in the conventional diesel engines. There have been identified the reasons for their difference and determined the values of the operating cycle parameters of hydrogen diesel engine, which provide the optimal correlation between the indicator values and the environmental performance. For a single-cylinder hydrogen-diesel engine MAN (S/D=300/240 mm/mm) the concentration of nitrogen oxides in combustion products is: [NOx] = 920 ppm, the mean effective pressure pe=9.0 bar, and the indicator efficiency of hydrogen diesel engine ηi=0.48. Overall, it can be…

Experimental PEM-Fuel Cell Range Extender System Operation and Parameter Influence Analysis

Vienna University of Technology-Johannes Höflinger, Peter Hofmann, Bernhard Geringer
  • Technical Paper
  • 2019-01-0378
To be published on 2019-04-02 by SAE International in United States
Fuel cells as alternative propulsion systems in vehicles can achieve higher driving ranges and shorter refueling times compared to pure battery-electric vehicles, while maintaining the local zero-emission status. However, to take advantage of pure battery electric travel, an externally rechargeable battery can be combined with a fuel cell range extender. As part of a project funded by the Austrian Research Promotion Agency (FFG), an efficient air supply system for a fuel cell range extender is being developed. To this end, a 25 kW PEM fuel cell system test bench was set up at the Institute for Powertrains and Automotive Technology (IFA) of the Vienna University of Technology. The different parameter influences of the test bench, in particular of the air supply system, were analyzed and evaluated in terms of stack/system efficiency and functionality. The control software of the test bench was specifically developed for the flexible operating parameter variation. All adjustable variables of the system (air ratio, stack temperature, pressure, etc.) were varied and evaluated at steady-state operating points. Likewise, the system was analyzed during…