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Fuel stabilizers have long been marketed to consumers to prevent oxidation and gum formation. In the past, gasoline storage for long periods of time was commonly limited to off-road equipment that was used infrequently. Cars and trucks that were driven regularly consumed the fuel in their tanks rapidly enough to avoid excessive fuel aging. However, plug-in hybrid electric vehicles (PHEVs) may be operated frequently without engine operation, raising the possibility that fuel may be stored in the tank for longer periods of time. Studies of the oxidation of gasoline have provided scientific understanding of the process, but there is little if any scientifically backed information aimed at aiding consumers in assessing the need to use an aftermarket fuel stabilizer if they anticipate lengthy periods of fuel storage in their fuel tank.

Exhaust gas recirculation (EGR) cooler fouling has become a significant issue for compliance with nitrogen oxides (NOx) emissions standards. In order to better understand fouling mechanisms, eleven field-aged EGR coolers provided by seven different engine manufacturers were characterized using a suite of techniques. Microstructures were characterized using scanning electron microscopy (SEM) and optical microscopy following mounting the samples in epoxy and polishing. Optical microscopy was able to discern the location of hydrocarbons in the polished cross-sections. Chemical compositions were measured using thermal gravimetric analysis (TGA), differential thermal analysis (DTA), gas chromatography-mass spectrometry (GC-MS), x-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS) and x-ray diffraction (XRD). Mass per unit area along the length of the coolers was also measured.

The CRC Fuels for Advanced Combustion Engines (FACE) Working Group has provided a matrix of experimental diesel fuels for use in studies on the effects of three parameters, Cetane number (CN), aromatics content, and 90 vol% distillation temperature (T90), on combustion and emissions characteristics of advanced combustion strategies. Various types of fuel analyses and engine experiments were performed in well-known research institutes. This paper reviews a collection of research findings obtained with these nine fuels. An extensive collection of analyses were performed by members of the FACE working group on the FACE diesel fuels as a means of aiding in understanding the linkage between fuel properties and combustion and emissions performance. These analyses included non-traditional chemical techniques as well as established ASTM tests. In a few cases, both ASTM tests and advanced analyses agreed that some design variables differed from their target values when the fuels were produced.

The present study was motivated by a need to expand information for consumers offered through the FuelEconomy.Gov website. To that end, a power-based modeling approach has been used to examine the effect of steady-speed driving on estimated range for model year 2020 – 2023 battery electric vehicles (BEVs). This approach allowed rapid study of a broader range of BEV models than could be accomplished through vehicle tests. Publicly accessible certification test results and other data were used to perform a regression between cycle-average tractive power requirements and the resulting electrical power. This regression enabled estimation of electric power and energy use over a range of steady highway speeds. These analyses in turn allowed projection of vehicle range at differing speeds. The projections agree within 6% with available 65 MPH manufacturer test data.

Compression and leak-down tests are frequently used to identify and diagnose failed engine power cylinders. It is also often desirable in research and testing programs to use these tests to monitor incremental changes in cylinder leakage. This paper investigates whether these tests are adequate in their present form to monitor incremental changes in cylinder leakage. Results are presented from two vehicle fleets at two test sites. Compression and leak-down tests were conducted on these fleets periodically during a mileage accumulation study. The results were used to establish the variability inherent in the compression and leak-down test processes. Comparisons between the results at the initial mileage test for the study vehicles with those at the final mileage test are shown to be largely within the uncertainty established for repeat assessments.

A prototype emissions control system consisting of a close-coupled lightoff catalyst, catalyzed diesel particle filter (CDPF), and a NOX adsorber was evaluated on a Mercedes A170 CDI. This laboratory experiment aimed to determine whether the benefits of these technologies could be utilized simultaneously to allow a light-duty diesel vehicle to achieve levels called out by U.S. Tier 2 emissions legislation. This research was carried out by driving the A170 through the U.S. Federal Test Procedure (FTP), US06, and highway fuel economy test (HFET) dynamometer driving schedules. The vehicle was fueled with a 3-ppm ultra-low sulfur fuel. Regeneration of the NOX adsorber/CDPF system was accomplished by using a laboratory in-pipe synthesis gas injection system to simulate the capabilities of advanced engine controls to produce suitable exhaust conditions. The results show that these technologies can be combined to provide high pollutant reduction efficiencies in excess of 90% for NOX and PM.