David L. Hilden

Bio: David L. Hilden is an academic researcher from General Motors. The author has contributed to research in topics: Diesel fuel & NOx. The author has an hindex of 14, co-authored 28 publications receiving 495 citations.

The contribution of engine oil to diesel exhaust particulate emissions

Abstract: A radioactive tracer technique was developed to determine the contribution of oil from an engine sump to exhaust particulates collected on a filter. The technique was applied to particulate emissions produced by an automotive diesel engine which was operated on an engine dynamometer over a range of steady-state conditions. Results indicated that from 1.5 to 25 mass percent of particulate matter, depending on speed and load, consisted of material from engine oil. The oil contribution to particulate matter's extractable organic portion varied from 16-80%. The greatest contribution from oil was generally observed at high test speeds.

The Contribution of Engine Oil to Particulate Exhaust Emissions from Light-Duty, Diesel-Powered Vehicles

Abstract: An apparatus was developed for the determination of the engine oil contribution to both total and extractable particulate exhaust emissions from diesel-powered vehicles during cyclic operation on a chassis dynamometer For the five vehicles tested, the percentage of the total particulate material that was derived from engine oil ranged from 7 to 14% Between 14 and 26% of the total particulate material was extractable with benzene-ethanol (80-20) solvent Oil contributed from 30 to 55% of the extractables in most cases Engine design and oil formulation generally appeared to have only small effects on the oil contribution to the particulate emissions A 1982 model-year vehicle with a 18L engine was an exception, since its oil contribution to the total and especially to the extractable particulate emissions (14 and 95%, respectively) was significantly greater than for any of the other vehicles

Diesel exhaust aftertreatment device regeneration system

Abstract: A diesel exhaust aftertreatment device regeneration system includes an exhaust conduit adapted to conduct exhaust gas to an exhaust gas aftertreatment device. The system further includes a low pressure bottom feed fuel injector having an inlet portion fully received within a chamber of an adaptor housing having a lower portion attached to the exhaust conduit. The housing is provided with fuel flow openings to allow low pressure fuel to circulate around and cool the fuel injector inlet portion within the chamber. Fuel injected into the exhaust conduit is preferably targeted toward a vaporization member, within the exhaust conduit, operative to absorb heat from the exhaust gas and vaporize fuel deposited thereon. A plurality of inwardly extending mixing baffles within the exhaust conduit intermediate the vaporization member and the aftertreatment device extend the mixing path to improve fuel vaporization for assisting regeneration of the device.

A Single-Cylinder Engine Study of Methanol Fuel-Emphasis on Organic Emissions

Abstract: Exhaust emission and performance characteristics of a single-cylinder engine fueled with methanol are compared to those obtained either with gasoline or a methanol-water blend. Our measurements of engine efficiency and power, and CO and NO/sub x/ emissions agree with trends established in the literature. Consequently, the emphasis is placed on organic emissions (unburned fuel including hydrocarbons, and aldehydes), an area in which there is no consensus in the literature. In all cases with methanol fueling, the unburned fuel (UBF) emissions were virtually all methanol as opposed to hydrocarbon compounds. Without special measures to overcome methanol's large heat of vaporization, UBF emissions were four times greater with methanol than those with gasoline. Similarly, aldehyde emissions were an order of magnitude greater with methanol. These high levels of organic emissions with methanol were related to inadequate fuel-air mixture preparation, which was caused by methanol's large heat of vaporization. Modifying the single-cylinder engine intake system to improve vaporization reduced UBF emissions 80 to 90% with methanol and 30 to 50% with gasoline. Aldehyde emissions were also significantly reduced by improving mixture preparation, but remained three to four times greater for methanol than for gasoline. Blending 10% water with methanol resulted in: (1) reducedmore » engine efficiency and power, (2) increased UBF emissions, (3) no measurable effect on aldehyde and CO emissions, and (4) reduced NO/sub x/ emissions. Our tests indicate that the advantages of blending water with methanol are outweighed by the disadvantages.« less

Microporous metal–organic framework with dual functionalities for highly efficient removal of acetylene from ethylene/acetylene mixtures

Abstract: The removal of acetylene from ethylene/acetylene mixtures containing 1% acetylene is a technologically very important, but highly challenging task Current removal approaches include the partial hydrogenation over a noble metal catalyst and the solvent extraction of cracked olefins, both of which are cost and energy consumptive Here we report a microporous metal-organic framework in which the suitable pore/cage spaces preferentially take up much more acetylene than ethylene while the functional amine groups on the pore/cage surfaces further enforce their interactions with acetylene molecules, leading to its superior performance for this separation The single X-ray diffraction studies, temperature dependent gas sorption isotherms, simulated and experimental column breakthrough curves and molecular simulation studies collaboratively support the claim, underlying the potential of this material for the industrial usage of the removal of acetylene from ethylene/acetylene mixtures containing 1% acetylene at room temperature through the cost- and energy-efficient adsorption separation process