Area of Specialization
Internal combustion engine; Engine emissions
Dr. Cheung obtained his BSc degree in 1978 and his MSc degree in 1988, from the Hong Kong University. He obtained his PhD from The Hong Kong Polytechnic University in 1995. After graduating in 1978, he joined a ship management company as assistant engineer and left in 1985 as marine superintendent. He worked as a graduate lecturer in a technical institute before joining The Hong Kong Polytechnic University as lecturer in 1990. He is now a full professor. Dr Cheung has conducted various research and consultancy projects in pollutant emissions and control in relation to internal combustion engines and motor vehicles. In recently years, he has extended his research interest to gas burners.
Brief Description of Three Research Projects
Project 1: Investigation of inverse diffusion flame burner
Impingement heating in which the flame jet impinges directly on the heating object has wide industrial and domestic application. In the Chinese community, impingement heat is used for cooking at home and in the restaurants.
There are two basic types of flame jets: premixed and non-premixed (diffusion). The flame to be investigated in this project is called inverse diffusion flame (IDF), which comprised of a central air jet surrounded by fuel port(s). There are very few investigations on IDF and almost none on impingement heating. However, IDF has a wider range of stable operation than premixed flame and is less sooty than diffusion flame. It also has potential for low NOx emission. Hence, it has good potential for application in impingement heating for better thermal performance and lower emissions.
This project will provide information for the design of IDF burners for impingement heating. It will contribute to the scientific and technological development of burners.
Project 2: Development of diesel engine with diesel/methanol compound combustion
Methanol is an alternative clean fuel. It is easily available, has no fuelling problem and is at a lower cost than diesel fuel. If methanol can be burned on existing diesel engines, it will help to reduce reliance on fossil fuel, reduce operating cost of vehicle users, and reduce particulate and nitrogen oxides emissions.
This project is concerned with the application of a diesel/methanol compound combustion technology to in service diesel engines for simultaneous reduction of particulate and nitrogen oxides emissions. With the compound combustion technology, methanol will be injected into the manifold to form a homogeneous mixture with air for combustion, while the original diesel fuel injection system will be retained but slightly modified to limit diesel fuel injection. At engine start and light loads, the engine will operate on diesel alone. At medium to high loads, the engine will operate on a homogeneous air/methanol mixture ignited by pilot diesel. This project aims to investigate the diesel/methanol injections under different engine operating conditions to achieve ultra low emissions.
Project 3: Influence of biodiesel on physical and chemical properties of particulate matter emitted from a diesel engine
Biodiesel has been blended with diesel fuel for application to diesel vehicles for reducing diesel fuel consumption, CO2 emissions and air pollution. The amount of biodiesel that is allowed in the blended fuel has been increasing.
Particulate matter originating from vehicle emissions has been linked to a myriad of adverse health outcomes, ranging from cancer to cardiopulmonary disease, and an array of environmental problems, including global warming and acid rain. The physical and chemical properties of particulate emissions determine their potential influence on the environment and human health. It is known that the use of biodiesel as a blended fuel may lead to a change in both the physical and chemical properties of the particulate. However, there is lack of detailed investigations on these changes.
Experiments will be carried out on a 4-cylinder diesel engine which is commonly found on diesel trucks in Hong Kong and in the mainland China. The engine will be tested under different engine operating conditions. At each engine operating condition, the exhaust particulate and co-pollutants will be collected and measured to analyze their physical and chemical properties. The physical properties to be investigated include the size of the primary soot particles, the shape of the agglomerated particles and the nanostructure of the soot particles, as observed under the transmission electronic microscope. On the chemical side, the fraction of volatile substance adsorbed by the particulate, the black carbon content of the particulate, the organic and inorganic compounds in the particulate will be analyzed using different analytical instruments. The amount of particle bound black carbon in the atmosphere can effectively absorb solar radiation thus affecting the energy redistribution and global climate. The organic compounds include carcinogenic polycyclic aromatic hydrocarbons (PAHs) etc. To link engine exhaust with health effect, this investigation will also include analysis of the oxidative potential of the particulate through the generation of reactive oxygen species (ROS) on cellular level. It is known that ROS are essential intermediates in metabolism with powerful oxidative potential, and are known to be capable of resulting in the oxidative damages.
This project provides information and scientific knowledge on the potential impact of biodiesel on the physical, chemical and toxicological properties of the particulate emitted by a diesel engine using biodiesel/diesel blended fuel, which are important for assessing the subsequent influence on our environment and human health. mation is important but is currently not available.
Most Recent Publications
1. Zhu RJ, Cheung CS and Huang ZH, “Particulate emission characteristics of a compression ignition engine fueled with Diesel-DMC blends” Aerosol Science and Technology 45(2011), 137-147
2. Zhang ZH, Cheung CS, Chan TL and Yao CD, “Experimental study on particulate emissions of a methanol fumigated diesel engine equipped with diesel oxidation catalyst” Aerosol Science and Technology 45(2011), 262-271
3. Cheung CS, Zhu RJ and Huang ZH, “Investigating on the gaseous and particulate emissions of a compression ignition engine fueled with diesel-dimethyl carbonate blends”, Science of the Total Environment 409 (2011), 523-529
4. Zhu L, Cheung CS, Zhang WG, Huang Z, “Combustion, performance and emission characteristics of a DI diesel engine fueled with ethanol-biodiesel blends”, Fuel 90(2011) 1743-1750
5. Zhang ZH, Tsang KS, Cheung CS, Chan TL, Yao CD, “Effect of fumigation methanol and ethanol on the gaseous and particulate emissions of a direct-injection diesel engine”, Atmospheric Environment 45(2011) 2001-2008
6. Zhu RJ, Cheung CS, Huang ZH, Wang XB, “Experimental investigation on particulate emissions of a direct injection diesel engine fueled with diesel-diethyl adipate blends”, Journal of Aerosol Science 42(2011) 264-276
7. Zhu RJ, Cheung CS, Huang ZH and Wang XB, “Regulated and unregulated emissions from a diesel engine fueled with diesel fuel blended with diethyl adipate”, Atmospheric Environment 45(2011) 2174-2181
8. Tsang KS, Hung WT and Cheung CS, “Emissions and fuel consumption of a Euro 4 car operating along different routes in Hong Kong”, Transportation Research Part D 16 (2011), 415-422
9. Dong LL, Cheung CS and Leung CW, “Combustion optimization of a port-array inverse diffusion flame jet”, Energy 36 (2011), 2834-2846
10. Zhu L, Cheung CS, Zhang WG, Huang Z, “Effect of charge dilution on gaseous and particulate emissions from a diesel engine fueled with biodiesel and biodiesel blended with methanol and ethanol”, Applied Thermal Engineering 31 (2011), 2271-2278
11. Lau Jason, Hung WT, Cheung CS, “On-board gaseous emissions of LPG taxis and estimation of taxi fleet emissions”, Science of the Total Environment, 409 (2011), 5292-5300
12. Wang Xiangang; Cheung CS, Di Yage, Huang Zuohua, “Diesel engine gaseous and particle emissions with diesel-oxygenate blends”, Fuel 94(2012), 317-323
13. Lau Jason, Hung WT, Cheung CS, “Observation of increase in emission from modern vehicles over time in Hong Kong using remote sensing”, Environmental Pollution 163(2012), 14-23
14. Lu Tian, Cheung CS, Huang Zhen, “Effects of engine operating conditions on the size and nanostructure of diesel particles”, Journal of Aerosol Science 47(2012), 27-38
15. Zhen HS, Cheung CS, Leung CW, Choy YS, “Effects of hydrogen concentrations on the emission and heat transfer of a premixed LPG-hydrogen flame”, International Journal of Hydrogen Energy 37(2012), 6097-6105
16. Zhen HS, Cheung CS, Leung CW and Choy YS, “A comparison of the emission and impingement heat transfer of LPG-H2 and CH4-H2 premixed flames”, International Journal of Hydrogen Energy 37(2012), 10947-10955
17. Lu Tian, Cheung CS, Huang Z, “Investigation on particulate oxidation from a DI diesel engine fueled with three fuels”, Aerosol Science and Technology 46(2012), 1349-1358
18. Lu Tian, Huang Z, Cheung CS and Ma Jing, “Size distribution of EC, OC and particle-phase PAH emissions from a diesel engine fueled with three fuels”, Science of the Total Environment 438(2012), 33-41
19. Lu Tian, Cheung CS, Huang Z, “Size-Resolved Volatility, Morphology, Nanostructure, and Oxidation Characteristics of Diesel Particulate”, Energy & Fuels 26(2012), 6168-6176