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Engine and flow reactor experiments were conducted to determine the impact of biodiesel relative to ultra-low-sulfur diesel (ULSD) on inhibition of the selective catalytic reduction (SCR) reaction over an Fe-zeolite catalyst. Fe-zeolite SCR catalysts have the ability to adsorb and store unburned hydrocarbons (HC) at temperatures below 300°C. These stored HCs inhibit or block NOx-ammonia reaction sites at low temperatures. Although biodiesel is not a hydrocarbon, similar effects are anticipated for unburned biodiesel and its organic combustion products. Flow reactor experiments indicate that in the absence of exposure to HC or B100, NOx conversion begins at between 100° and 200°C. When exposure to unburned fuel occurs at higher temperatures (250°-400°C), the catalyst is able to adsorb a greater mass of biodiesel than of ULSD. Experiments show that when the catalyst is masked with ULSD, NOx conversion is inhibited until it is heated to 400°C.

Experiments were conducted with ultra low sulfur diesel (ULSD) and 20% biodiesel blends (B20) to compare lube oil dilution levels and lubricant properties for systems using late in-cylinder fuel injection for aftertreatment regeneration. Lube oil dilution was measured by gas chromatography (GC) following ASTM method D3524 to measure diesel content, by Fourier transform infrared (FTIR) spectrometry following a modified ASTM method D7371 to measure biodiesel content, and by a newly developed back-flush GC method that simultaneously measures both diesel and biodiesel. Heavy-duty (HD) engine testing was conducted on a 2008 6.7L Cummins ISB equipped with a diesel oxidation catalyst (DOC) and diesel particle filter (DPF). Stage one of engine testing consisted of 10 consecutive repeats of a forced DPF regeneration event. This continuous operation with late in-cylinder fuel injection served as a method to accelerate lube-oil dilution.

It is estimated that operating continuously on a B20 fuel containing the current allowable ASTM specification limits for metal impurities in biodiesel could result in a doubling of ash exposure relative to lube-oil-derived ash. The purpose of this study was to determine if a fuel containing metals at the ASTM limits could cause adverse impacts on the performance and durability of diesel emission control systems. An accelerated durability test method was developed to determine the potential impact of these biodiesel impurities. The test program included engine testing with multiple DPF substrate types as well as DOC and SCR catalysts. The results showed no significant degradation in the thermo-mechanical properties of cordierite, aluminum titanate, or silicon carbide DPFs after exposure to 150,000 mile equivalent biodiesel ash and thermal aging. However, exposure of a cordierite DPF to 435,000 mile equivalent aging resulted in a 69% decrease in the thermal shock resistance parameter.

In some studies, a relationship has been observed between increasing ethanol content in gasoline and increased particulate matter (PM) emissions from vehicles equipped with spark ignition engines. The fundamental cause of the PM increase seen for moderate ethanol concentrations is not well understood. Ethanol features a greater heat of vaporization (HOV) than gasoline and also influences vaporization by altering the liquid and vapor composition throughout the distillation process. A droplet vaporization model was developed to explore ethanol’s effect on the evaporation of aromatic compounds known to be PM precursors. The evolving droplet composition is modeled as a distillation process, with non-ideal interactions between oxygenates and hydrocarbons accounted for using UNIFAC group contribution theory. Predicted composition and distillation curves were validated by experiments.

A 2002 model year Cummins ISB 300 engine was used to examine the effects of shifting engine parameters from their stock settings on the performance of a 20% biodiesel blend (B20). The objective of this work was to determine if it is possible to use a more optimal engine calibration to eliminate the small fuel economy and NOx emission penalties typically observed for B20 in comparison to petroleum diesel, while preserving the significant reduction in PM emissions that is also typically observed. Tests were conducted at multiple steady-state operating modes. Two engine parameters were modified: a 1° advance in fuel injection timing and a 4% exhaust gas recirculation valve position increase. For B20, the simple calibration changes yielded an average decrease in NOx emissions of 2% with a brake-specific fuel consumption penalty of less than 1%, while still reducing PM emissions overall in comparison to B0 and the stock calibration.

A relationship has been observed between increasing ethanol content in gasoline and increased particulate matter (PM) emissions from direct injection spark ignition (DISI) vehicles. The fundamental cause of this observation is not well understood. One potential explanation is that increased evaporative cooling as a result of ethanol’s high HOV may slow evaporation and prevent sufficient reactant mixing resulting in the combustion of localized fuel rich regions within the cylinder. In addition, it is well known that ethanol when blended in gasoline forms positive azeotropes which can alter the liquid/vapor composition during the vaporization process. In fact, it was shown recently through a numerical study that these interactions can retain the aromatic species within the liquid phase impeding the in-cylinder mixing of these compounds, which would accentuate PM formation upon combustion.

Gasoline Direct Injection (GDI) has become the preferred technology for spark-ignition engines resulting in greater specific power output and lower fuel consumption, and consequently reduction in CO2 emission. However, GDI engines face a substantial challenge in meeting new and future emission limits, especially the stringent particle number (PN) emissions recently introduced in Europe and China. Studies have shown that the fuel used by a vehicle has a significant impact on engine out emissions. In this study, nine fuels with varying chemical composition and physical properties were tested on a modern turbo-charged side-mounted GDI engine with design changes to reduce particulate emissions. The fuels tested included four fuels meeting US certification requirements; two fuels meeting European certification requirements; and one fuel meeting China 6 certification requirements being proposed at the time of this work.

An inhibitor package which is silicate-, nitrate-, borate- and phosphate-free has been developed as the basis for a world-wide automotive coolant formulation. The formulation contains aliphatic mono- and dicarboxylic acids and tolyltriazole as the sole inhibitors. Formulations containing carboxylic acid inhibitors have been studied in ASTM bench tests and found to sufficiently protect all prevalent cooling system metals. In addition, fleet tests have shown that carboxylic acid inhibitors deplete much more slowly than conventional inhibitors, making possible a much longer life coolant. Results from laboratory tests which simulate extended usage indicated that carboxylic acid-containing coolants have a significantly longer life span for the protection of all cooling system metals. Finally, the carboxylic acid/tolyltriazole inhibitor package is completely adaptable to a propylene glycol base.

High lead solder coupons are frequently tested in ASTM D 1384-87 and D 2570-91 tests to determine the corrosion protection provided by engine coolants. In contrast to 70/30 solder, high lead solder is often observed to show relatively high corrosion rates in D 1384-87 testing. Surprisingly, the high lead solder corrosion rates tend to be lower in the D 2570-91 test, despite the longer duration of this test. The basis of this effect has been investigated in different coolant formulations and in both ethylene glycol and propylene glycol. The corrosion of high lead solder was found to be directly related to the presence of oxygen in the D 1384-87 test. Replacement of the air purge with a nitrogen purge significantly reduced the corrosion rate of high lead solder in inhibited coolants. These results are interpreted in terms of the solder composition.

The effect of small amounts of silicate on coolant performance has been studied. The corrosion protection provided by different coolant technologies was evaluated for different silicate contents. This work includes results from electrochemical tests and static and dynamic heat-rejecting tests on aluminum surfaces. The results indicate that small amounts of silicate have a negative effect on the corrosion protection of aluminum. Depletion of silicates can therefor be expected to affect aluminum heat-rejecting surfaces. The use of carboxylic acid corrosion inhibitors can overcome this problem.

Automobile coolant pump failure rates have been observed to be influenced by the coolant inhibitor package. A fleet test consisting of 196 1991 Ford Crown Victoria taxi cabs was utilized to test six coolant formulations. Four of the test formulations were monobasic/dibasic organic acid technology coolants and two were traditional technology coolants containing nitrate, phosphate, and silicate. Coolant pump failure rates were monitored as a function of mileage. Results indicate that the service life of coolant pumps for those systems employing organic acid technology coolants was significantly greater than those systems utilizing traditional inhibitor technology coolants.

Mixtures of a novel corrosion inhibitor, based on the synergistic combination of aliphatic mono- and dibasic acids with a traditional coolant have been evaluated in: a stability test an electrochemical test the ASTM D 1384 Glassware Corrosion Test the ASTM D 4340 Aluminum Heat-Rejection Test a Dynamic Heat-Transfer Test. This paper discusses the results of these tests and the relevance of the tests in assessing the performance of the coolant mixtures. Recommendations are made to the selection of methods that provide significant information on coolant compatibility.

Field testing of an extended life coolant technology in Class 8 trucks, equipped with Caterpillar C-12 engines revealed excellent coolant life with negligible inhibitor depletion to 400,000 miles with no refortification and no coolant top-off. In separate evaluations in Caterpillar 3406E equipped trucks, extended corrosion protection and component durability were established out to 700,000 miles, without the need for refortification other than top-off.

The transition from the current Shuttle Space Transportation System (STS) payload delivery capability to an advanced launch system has been the topic of several studies and proposals. The need for an early, reliable, low cost heavy lift vehicle has been identified and supported by NASA as a response to that need. This paper will provide a brief background and description of the Shuttle-C, and will primarily focus on cargo bay sizing and manifesting for one of the three identified design reference missions: Space Station Freedom assembly.

Evaporative cooling of the fuel-air charge by fuel evaporation is an important feature of direct-injection spark-ignition engines that improves fuel knock resistance and reduces pumping losses at intermediate load, but in some cases, may increase fine particle emissions. We have reported on experimental approaches for measuring both total heat of vaporization and examination of the evaporative heat effect as a function of fraction evaporated for gasolines and ethanol blends. In this paper, we extend this work to include other low-molecular-weight alcohols and present results on species evolution during fuel evaporation by coupling a mass spectrometer to our differential scanning calorimetry/thermogravimetric analysis instrument. The alcohols examined were methanol, ethanol, 1-propanol, isopropanol, 2-butanol, and isobutanol at 10 volume percent, 20 volume percent, and 30 volume percent.

Conventional diesel combustion, also known as Mixing-Controlled Compression Ignition (MCCI), is expected to be the primary power source for medium- and heavy-duty vehicles for decades to come. Displacing petroleum-based ultra-low-sulfur diesel (ULSD) as much as possible with low-net-carbon biofuels will become necessary to help mitigate effects on climate change. Neat biofuels may have difficulty meeting current diesel fuel standards but blends of 30% biofuel in ULSD show potential as ‘drop-in’ fuels. These blends must not make significant changes to the combustion phasing of the MCCI process if they are to be used interchangeably with neat ULSD. An important aspect of MCCI phasing is the ignition delay (ID), i.e. the time between the start of fuel injection and the initial premixed autoignition that initiates the MCCI process.

Mixing controlled compression ignition, i.e., diesel engines are efficient and are likely to continue to be the primary means for movement of goods for many years. Low-net-carbon biofuels have the potential to significantly reduce the carbon footprint of diesel combustion and could have advantageous properties for combustion, such as high cetane number and reduced engine-out particle and NOx emissions. We developed a list of over 400 potential biomass-derived diesel blendstocks and populated a database with the properties and characteristics of these materials. Fuel properties were determined by measurement, model prediction, or literature review. Screening criteria were developed to determine if a blendstock met the basic requirements for handling in the diesel distribution system and use as a blend with conventional diesel. Criteria included cetane number ≥40, flashpoint ≥52°C, and boiling point or T90 ≤338°C.

For several years now, organic acid based coolants and heat exchange fluids have been introduced on the automotive and industrial market place. The organic acid based coolants provide improved high temperature aluminum corrosion protection and longer drain intervals when compared to traditional coolants. In order to evaluate the organic acid based coolant quality in the field; the end user needs to be able to check several physico-chemical parameters of the coolant. First of all the amount of carboxylate based inhibitors should be determined because the customers can top the system with water. As a result the carboxylates can drop under the minimum required inhibitor level.

A fleet test using Propylene Glycol (PG) based coolant, recycled PG based coolant and PG mixed with ethylene glycol (EG) coolant was conducted using a fleet of employee vehicles. These coolants were all formulated using extended life, silicate free additive technology. This fleet consisted of a wide range of vehicle types and was run to verify the effectiveness of utilizing a PG based coolant across a broad spectrum of vehicle types. The results from this fleet test will be discussed. Results will include coolant analysis, parts inspection and vehicle repair histories. The environmental (toxicological) benefits of such a coolant will also be discussed.

Previous studies examined the effect of low levels of silicate (∼<75ppm Si) on hot aluminum corrosion protection. The corrosion protection provided by different coolant technologies was evaluated at different silicate levels. The results indicated that small amounts of silicate have a negative effect on the corrosion protection of aluminum. This work will examine these results and evaluate the effectiveness of different laboratory tests for determining coolant “compatibility.” Results will be examined from several bench and fleet tests showing the effect of coolant mixing on the corrosion rates in various environments. The bench test results will include laboratory glassware and dynamic tests that have been used historically to evaluate coolant compatibility. Differences between the test methods will also be evaluated to determine the relevance of each test procedure in light of the fleet observations.