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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Use of clove stem oil as an alternative fuel for diesel engines

Abdulhamid, Haji January 2008 (has links)
Thesis (MTech. degree in Mechanical Engineering.)--Tshwane University of Technology, 2008.
2

Simultaneous diesel and natural gas injection for dual-fuelling compression-ignition engines

White, Timothy Ross, Mechanical & Manufacturing Engineering, Faculty of Engineering, UNSW January 2006 (has links)
The introduction of alternative fuels such as natural gas is likely to occur at an increasing rate. The dual-fuel concept allows these low cetane number fuels to be used in compression-ignition (CI, diesel) type engines. Most CI engine conversions have pre-mixed the alternative fuel with air in the intake manifold while retaining diesel injection into the cylinder for ignition. The advantage is that it is simple for practical adaptation; the disadvantage is that good substitution levels are only obtained at midload. A better solution is to inject both the alternative and diesel fuels directly into the cylinder. Here, the fuel in the end-zone is limited and the diesel, injected before the alternative, has only a conventional ignition delay. This improves the high-end performance. Modern, very high pressure diesel injectors have good turndown characteristics as well as better controllability. This improves low-end performance and hence offers an ideal platform for a dual-fuel system. Several systems already exist, mainly for large marine engines but also a few for smaller, truck-sized engines. For the latter, the key is to produce a combined injector to handle both fuels which has the smallest diameter possible so that installation is readily achieved. There exists the potential for much improvement. A combined gas/diesel injection system based on small, high pressure common-rail injectors has been tested for fluid characteristics. Spray properties have been examined experimentally in a test rig and modelled using CFD. The CFD package Fluent was used to model the direct-injection of natural gas and diesel oil simultaneously into an engine. These models were initially calibrated using high-speed photographic visualisation of the jets. Both shadowgraph and schlieren techniques were employed to identify the gas jet itself as well as mixing regions within the flow. Different orientations and staging of the jets with respect to each other were simulated. Salient features of the two fuel jets were studied to optimise the design of a dual-fuel injector for CI engines. Analysis of the fuel-air mixture strength during the injection allowed the ignition delay to be estimated and thus the best staging of the jets to be determined.
3

Alternative fuels and reduction of air pollution in Hong Kong

Hui, Lai-yee., 許麗儀. January 2001 (has links)
published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
4

Combustion stress in compression-ignition engines.

Taylor, Andrew Bruce. January 1989 (has links)
South Africa produces alternative fuels from a number of different sources. The properties of a fuel are known to affect the nature of combustion in compression-ignition engines significantly, and have occasionally resulted in engine failures. Combustion analyses have been conducted on a wide range of fuels and combustion has been thoroughly quantified. However, the role played by the different combustion variables in failures was not known. The result was that it was not possible to predict the implications of variations in the nature of combustion. There was thus a need to investigate the relative role of combustion variables in the failure of engines. The mechanisms of combustion and engine failure were studied. All the variables required to determine combustion and engine durability were measured simultaneously. This research required the development of a complete engine research facility as well as specialized transducers. Fast response surface thermocouples were designed and constructed in order to monitor transient surface temperatures. Heat transfer rates were then calculated with the aid of Fourier analysis. Dynamic stresses were monitored by strain-gauges applied to the engine. A special high speed data acquisition system was developed. An existing heat release model was modified and used to calculate combustion rates. A comprehensive finite element model was developed to calculate piston temperatures and stresses. The role of each combustion variable in stress and durability was investigated by statistical analysis. The results successfully identified the causes of combustion related engine failures. The primary cause of engine failure was found to be thermal loading. The principal cause of any variation in thermal loading and thus engine durability was maximum cylinder pressure. The life of the engine was proved to be determined almost entirely by peak cylinder pressure. The role of the rate of pressure rise was proved to be insignificant. All the implications of variations in the nature of combustion can now be determined accurately. It will thus be possible to optimise engine modifications and fuel properties before validation by durability testing. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1989.
5

A policy analysis of the liquefied petroleum gas vehicles scheme in Hong Kong

溫雅惠, Wan, Ah-wai, Angie. January 2002 (has links)
published_or_final_version / Public Administration / Master / Master of Public Administration
6

Cleaner alternative fuels for vehicles: a cleaner future for Hong Kong

Ng, Bing, Benson., 吳賓. January 2001 (has links)
published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
7

Comparison of electric vehicles, hybrid vehicles & LPG vehicles

Ngan, Shing-kwong., 顔成廣. January 1999 (has links)
published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
8

LPG vehicles: will they replace small diesel vehicles in Hong Kong?

Tsui, Bing-cheung., 徐秉璋. January 1998 (has links)
published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
9

A study of sustainable fuel in public transport: the case of public light buses in Hong Kong

Ng, Tze-on., 吳子安. January 2001 (has links)
published_or_final_version / Transport Policy and Planning / Master / Master of Arts in Transport Policy and Planning

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