Search Results

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.

Fine water mist has become a commercial technology for fire suppression in multiple applications. With funding from NASA, ADA Technologies, Inc. (ADA) is developing a handheld fine water mist fire extinguisher for use on manned spacecraft and in future planetary habitats. This design employs only water and nitrogen as suppression agents to allow local refill and reuse. The prototype design incorporates features to generate a uniform fine water mist regardless of the direction of the gravitational vector or lack of gravity altogether. The system has been proven to extinguish open fires and hidden fire scenarios in tests conducted at the Colorado School of Mines (CSM). This design can be deployed as a portable extinguisher or as an automated system for local fire protection in instrument racks or storage spaces. Continued development will result in prototype hardware suitable for use on future manned spacecraft.

The effect of diesel cetane number, total aromatic content T90, and fuel nitrogen content on regulated emissions (HC, CO, NOx, and PM) from a 1991 DDC Series 60 engine were measured Emissions tests were conducted using the EPA heavy-duty transient test (CFR 40 Part 86 Subpart N) at a laboratory located 5,280 feet (1609 m) above sea level. The objective of this work was to determine if the effect of fuel chemistry at high altitude is similar to what is observed at sea level and to examine the effect of specific fuel chemistry variables on emissions. An initial tea series was conducted to examine the effect of cetane number and aromatics. Transient emissions for this test series indicated much higher (50 to 75%) particulate emissions at high altitude than observed on the same model engine and similar fuels at sea level.