| Author: | Wei, Long |
| Title: | Performance and emissions of a direct-injection diesel engine fueled with biodiesel and diesel |
| Advisors: | Cheung, C. S. (ME) |
| Degree: | M.Sc. |
| Year: | 2015 |
| Subject: | Biodiesel fuels -- Research. Diesel motor. Hong Kong Polytechnic University -- Dissertations |
| Department: | Department of Mechanical Engineering |
| Pages: | xiii, 118 pages : illustrations (some color) |
| Language: | English |
| Abstract: | To reduce air pollution and reliance on fossil fuel, biodiesel has been widely investigated for use in diesel engines. The purpose of this study is to clarify the effects of biodiesel on diesel engine performance and emission characteristics. Experiments were conducted on a direct-injection diesel engine fueled with diesel, B20 (20% biodiesel and 80% diesel on volume basis, v/v), B50, B75 and biodiesel. Experiments were carried out on the Japanese 13-mode test cycle which covers different engine loads and engine speeds. Biodiesel could increase the brake specific fuel consumption (BSFC), in-cylinder temperature and in-cylinder pressure, lower the maximum heating release rate, shorten the total combustion duration and increase the thermal efficiency at heavy loads. The decreases of PM, CO and HC emissions are observed, while an increase of NOX is also found. Regarding the unregulated gaseous emissions, biodiesel could increase the emissions of formaldehyde, acetaldehyde, propene, ethene, 1,3-butadiene and benzene, but decrease the emissions of toluene and xylene. Biodiesel could also reduce the total number concentration (TNC) in exhaust gas and decrease the geometric mean diameter (GMD) of particles. Particle samples were collected at 1920 rpm with different loads for analysis of particulate morphology, nanostructure and oxidation characteristics. Particles from biodiesel or low loads have smaller primary particle size compared with particles formed by using diesel or at heavy loads. The results also indicate that particles produced from biodiesel or low loads have more disordered nanostructure with shorter and more curved graphene layer compared with the particles produced by using diesel or in heavy loads. By analyzing the oxidation properties of the particles, it can be found that biodiesel particles have higher volatile mass fraction than diesel particles. The oxidation reaction rate of biodiesel particles is also faster than that of diesel particles. |
| Rights: | All rights reserved |
| Access: | restricted access |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| b2825403x.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 9.35 MB | Adobe PDF | View/Open |
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