Dieselengine exhaust contains large numbers of fine particles that degrade air quality and contribute to adverse human health effects. This study aims to characterize the changes ofnanoparticle number emission characteristics fromaheavy-dutydieselengine, operating with selected blends of low-sulfur biodiesel (B2_S50, B10, and B20) andengine loads (0%, 25%, 50%, 75%) under steady cycle. Raw exhaust were sampled with a rotating disc thermo-dilution system, followed by measurements of number size distributions of 10 – 1000 nm non-volatile particles using a scanning mobility particle sizer and condensation particle counter (SMPS) system. The results show that the particle number emission concentrations decrease with
2 Institute of Environmental Engineering, National Sun Yat-sen University, Kaohsiung 804, Taiwan
The development of biodiesels is being driven by the need for reducing emissionsfromdiesel engines without modifying engines and for saving energy. The major obstacle to biodiesel commercialization is the high cost of raw materials. Biodieselfrom waste cooking oil is an economical source and an effective strategy for reducing the raw material cost. Although biodiesels made from waste cooking oil have been previously investigated, PAH emissionsfromheavy-dutydiesel engines (HDDEs) with catalyzer fueled with biodieselfrom waste cooking oil and its blend with ultra-low sulfur diesel (ULSD) for the US-HDD transient cycle have seldom been addressed. Experimental results indicate that ULSD/WCOB (biodiesel made from waste cooking oil) blends had lower PM, HC, and CO emissions but higher CO 2 and NO x emissions when compared with that of ULSD. Using ULSD/WCOB blends instead of ULSD decreased PAHs by 14.1%–53.3%, PM by 6.80%–15.1%, HC by 6.76%–23.5%, and CO by 0.962%–8.65% but increase CO 2 by 0.318–1.43% and NO x by 0.384–1.15%. Using WCOB is an economical source and an effective strategy for reducing cost, and solves the problem of waste oil disposal.
and hence the OC absorbed on the EC. Substantially higher OC/EC ratios (> 3) were observed at idle and low load, compared to that of < 1 at medium and high load.
The relatively higher OC emissions are likely due to the less complete combustion and hence lower combustion temperature at idle and low load. In addition, the OC emissions decreased significantly from low to medium loadand then remained relatively unchanged from medium to high load. Unlike OC, the EC emissions increased with increasing load. Overall, the present study shows that fuels, aftertreatments andengineload can lead to compositional changes in the carbonaceous PM, of which need to be taken into account for assessing their impact on atmospheric chemistry and human health.
combustion temperature but decreased post-flame soot oxidation at higher engine speed, respectively.
The overall results indicate that the relative importance of particulate OC and EC varies largely with engineloadand the use of aftertreatments such as the DOC and DPF and, to a lesser extent, for low-percentage (10%) biodiesel. Specifically, the semivolatile OC in PM is significantly more important at idle and low load or when the DPF is in place, whereas nonvolatile EC is more prominent at medium and high load or when aftertreatments are not in place. It is notable that the OC in PM are strongly associated with cell toxicity. On the other hand, the reduction of fuel sulfur content from <50 ppmw to <10 ppmw has negligible effectson the carbonaceous composition in dieselengine particles, though its relation with SO 2 and sulfate emissions was not evaluated in the present work. Finally, the high-efficiency DPF may not be enough for high-PM emitting diesel engines to meet the current standards, particularly for those uncontrolled or poorly maintained engines. As dieselengine, emission control technology andbiodiesel are finding increasing worldwide application in abating air pollution and global warming, such carbonaceous composition changes would impact the roles of PM in adverse human health and atmospheric chemistry, and its use in source apportionment.
2.2. Sample collection
A MOUDI equipped with aluminum ﬁlters (with diam- eters of 37 mm) was used to collect size-resolved samples.
Particles with diameter less than 0.056 m m were collected but gas phase PAHs may be adsorbed when the exhaust gas goes through the Teﬂon ﬁlter. Therefore, this research is focused on particles with diameter between 0.056 w 18 m m. Therefore, the sum of MOUDI mass is less than total GPM mass. These impactors effectively sepa- rated the particulate matters into 9 ranges with the fol- lowing equivalent cut-off diameters; 18–10 m m (stage 9), 10–5.6 m m (stage 8), 5.6–3.2 m m (stage 7), 3.2–1.8 m m (stage 6), 1.8–1.0 m m (stage 5), 1.0–0.52 m m (stage 4), 0.52–0.31 m m (stage 3), 0.31–0.166 m m (stage 2) and 0.166–0.056 m m (stage 1). Silicon grease was applied to the surface of each ﬁlter installed in the MOUDI. Before sampling, the greased ﬁlter-strips were baked in a 60 C oven for 90 min to stabilize the silicon grease. Thus, parti- cle bounce between the different stages of the MOUDI dur- ing the sampling could be minimized. Before and after each sampling, the ﬁlters were dried for 24 h in a desicca- tor at 25 C with 40% relative humidity. They were then weighed again. The suspended GPM concentration is determined by dividing the mass by the volume of sam- pled air.
treament system, or development of alternative fuels technology.
Due to increasing environmental awareness, biodiesel is gaining recognition in the advanced nations, such as U.S.A., France and Austria, as a renewable fuel and it may be used as an alternative to diesel fuel with no engine modiﬁcations. Biodiesel can be made from alcohol and vegetable oils, which are both agriculturally derived products. Biodiesel made from such renewable resources is safer due to increased ﬂash point, biodegrad- able, containing little or no sulfur, tending to reduce visible smoke from the exhaust, and an environmentally innocuous nature. Currently, biodiesel is very expensive to make from new feedstocks. One way to reduce the cost ofbiodiesel is to use less expensive feedstocks such as waste fryer oil from the food processing industry [1–3]. Methyl esters from vegetable oils (biodiesel) have many characteristics that make them attractive as a fuel for combus- tion in direct injection compression ignition engines [4–6]. Compared with diesel fuel, combustion of methyl esters was known to reduce smoke opacity, particulate matter (PM), hydrocarbons and carbon monoxide emissions while slightly increasing NO x emissionsand delivering comparable engine performance [2, 3, 7–9]. Likewise biodiesel/diesel blends have also shown similar performance andemissions to diesel fuel while burned in unmodiﬁed diesel engines [4–6]. The 20/80 and 30/70 blends ofbiodiesel to diesel fuel are used in this study because they were determined to be the optimum ratio for abiodiesel/diesel blends by many studies [3, 9, 10].
2011 International Conference on Aerosol Science and Technology
ELECTRON MICROSCOPY OBSERVATIONS OFDIESELENGINEAND WORKPLACE AEROSOLS
Pei-Hsuan Chen, Yi-Jyun Liou, Wei-Lun Chang, Yun-Hua Lin, Li-Hao Young *
Department of Occupational Safety and Health, China Medical University, Taichung 40402, Taiwan
Y. K. Chin and F. E. Coats, “Engine Dynamics: Time-Based Versus Crank-Angle Based,” SAE Paper No. 860412, 1986.
M. Nasu, A. Ohata, and S. Abe, “Model-Based Fuel Injection Control System for SI Engines,” SAE Paper No.961188, 1996.
B. A. Giivenp and B. Sencer and M Giray and L. Giivenq, “Use ofa Simulink Engine Blockset in Real Time Hardware in the Loop Simulations, ” 0-7803-8599-3/04/$20.00, 2004 IEEE H. M. Koegeler and G. Regner and T. Sams and K. Gschweitl, “Using Simulation and Optimization Tools to Decide Engine Design Concepts, ” SAE Paper No.2000-01-1267, 2000.
N recent years, with continuous rise of oil price, how to develop alternative energy source has become a hot topic around the world. After the Kyoto Protocol has been exercised, a new trend of international environment protection has emerged, and various industries in Taiwan have proposed suggestions for new energy policy. Since “The 2nd National Energy Conference,” the government has set CO 2 control mechanism actively and expected decrease of 38 million MT by the end of 2015, 58.68 million MT by 2020, and 78.41 million MT by 2025. The utilization of renewable energy is expected to reach 7,000~8,000MW by 2020 and 8,000~9,000MW by 2025, to attain the goal for total installed capacity penetration 12% or energy structure penetration 4~6%. The renewable energy development projects include biomass, wind power, photovoltaic system, solar heat, hydrogen energy, fuel cell, oceanic energy, geothermal heat, etc. The projects also cover planning offshore wind farms with scale of economy and fostering the development of the domestic wind industry .
Please summarize the entire research, teaching, or science and technology R&D and management work process (To be completed by the employee)
A diverse range of research and educational activities were carried out during my stay at the Environmental Engineering Department at NCKU. The main focus was joint-research with Professor Wen-Jyh Lee’s group on alternative energy development and air toxic emissions characterization. I discussed with Professor Lee and his students several ideas and I reviewed/commented manuscripts the students prepared. Professor Lee and I also brainstormed many ideas how to promote the Aerosol and Air Quality Journal, of which he is the chief editor and I am an editor. We also exchange opinions on various academic issues, such as lab safety, vision for the department, and young faculty mentoring. I also spent quality time with Professor Hsin Chu and his students to discuss research in carbon dioxide capture and conversion. Similarly, I reviewed manuscripts prepared by his students. We also discussed in length about inviting him giving lectures in my class at University of Florida in Fall 2013 as a way of mutual scholarly exchange. Professor Chih-Hua Chang asked me to comment on his manuscript, which I gladly provided my suggestions. I also discussed with him about visiting research at various institutions having research programs in his research direction. I also met with the majority of faculty in the department individually and as a group to introduce each other’s research expertise. Many ideas were exchanged regarding the challenges the Department is facing and how to move the Department to the next stage.
Knock control systems are widly used in cars to enhance engine performance and numerous methods of determining engine knock are developed.It is important to know how closely these methods are correlated.In the present thesis,evaluation and correlation of these methods are performed. The results show : the integration of squared pressure oscillation has the highest sensitivity among the methods using cylinder pressure for knock detection.Among the methods using accelerometer for knock detection,the integration of rectified vibration signal is the one best correlated with the method using cylinder pressure for knock detection.So when an
The purpose of this research was first to investigate the vehicle characteristics for diesel cars in a bedrock dynamometer smoke examination station. Secondly, the effectsofengine size and age, odometer reading on mean smoke opacity at no loadand full loads (smoke 100%, 60%, and 40%) conditions were examined. Moreover, the vehicle characteristics and smoke check data were
examined by Analysis of Variance (ANOVA). The specific objectives were to explore the smoke emissions under various examining stages and determine the relationship between vehicle characteristics and smoke opacity. Results show vehicle age was a significant factor affecting the smoke emissions under no loadand full load conditions. It was found the mean smoke opacity increases with an increase in vehicle ages. The mean no-load smoke opacities for roadside inspection diesel vehicles were significant higher those of at dynamometer smoke examination station. Because the fact that smoke emissionsfrom roadside vehicles reflect the real situation, high smoke emissionsfrom roadside vehicles were observed. In contrast, the lower smoke emissions for vehicles examining at dynamometer smoke examination station were attributed to the vehicle sources from either by visual determination or
The above traditional air pollutants were measured only for HDVs in this study. Particulate PAHs were collected by Pallflex filters. Before taking the samples, the filters were placed in an oven at 450°C for 8 h to burn up any organic compounds that might be present in the filters. The PAH sampling system was equipped with a sampling probe, a cooling device, a glass cartridge, a pump anda flow meter. A PAH sampling system with a tube-type glass fiber filter (cleaned by heating to 450°C) was used to collect particulate matter and particle-phase PAHs. A glass cartridge packed with XAD-16 resin and supported by a polyurethane foam (PUF) plug was used to collect the gas phase PAHs. After each sampling cycle the sampling train was rinsed with n-hexane. Breakthrough tests were conducted by two stages of XAD-16/PUF cartridge. Each stage of cartridge was analyzed individually and compared for the PAH mass collected. Breakthrough tests results showed that there was little PAH mass found in the cartridge of the second stage. After sampling, each PAH- containing sample was Soxhlet extracted with a mixed solvent (n-hexane and dichloromethane, 500 mL/L each) for 24 h. The extract was then concentrated by purging with ultra-pure nitrogen to 2 mL for the cleanup procedure and then reconcentrated to 0.5 mL with ultra-pure nitrogen.
readers have had the required background, we will use a one-hop network as an example to present how to combine the discrete-event methodology with the kernel re-entering methodology.
3.1. Tunnel network interface
Tunnel network interfaces is the key facility in the kernel re-entering methodology. A tunnel network inter- face, available on most UNIX machines, is a pseudo network interface that does not have a real physical net- work attached to it. The functions ofa tunnel network interface, from the kernel’s point of view, are no diﬀerent from those of an Ethernet network interface. A network application program can send out its packets to its destination host through a tunnel network interface or receive packets froma tunnel network interface, just as if these packets were sent to or received froma normal Ethernet interface. Currently, the NCTUns installation script automatically creates 4,096 tunnel interfaces by default. Since a tunnel network interface is a software object and occupies little memory space in the kernel, this number can be further increased with- out any problem.
include correlations for the transport properties. This was conve- nient since much of the methodology was similar.
2.4. Real-ﬂuid model computational speed
In assessing the computational overhead associated with using the real-ﬂuid property sub-model, numerical experiments of simu- lating some converging–diverging pipe ﬂows with ideal gas and li- quid oxygen working ﬂuids were conducted to quantify the CPU time overhead when the real-ﬂuid model is activated. The results show an overall CPU time increase of about 85% for the real-ﬂuid cases. These results indicate that there are rooms for improvement in order to enhance the turnaround time of running multi-phase ﬂow problems. To improve the computational efﬁciency, a real- ﬂuid table lookup procedure was developed for the present CFD model. This method is much more efﬁcient than the original real-ﬂuid model which involves the inversion of curve-ﬁt data describing the equation of state. In average, the real-ﬂuid table lookup model is only 15% slower than its ideal-gas counterpart.
→ Established a business unit in Gujarat in 1972 through a joint venture with the Indian company, Lakhanpal. Manufacturing unit located at Vadodara where it manufactures dry cell batteries.
→ Founded in 1908, GM is among the world’s largest automobile makers. Headquartered in Detroit (USA), GM manufactures cars and trucks in 158 facilities and offer a comprehensive range of vehicles in more than 120 countries. GM has been the global automotive sales leader since 1931 and employs about 202,000 people globally.
The main purpose of this study is to establish the multiple injection performance optimization methodology for a high pressure Direct Injection Common Rail (DICR) dieselengine. The hardware and software of the engine control system were combined with the engine dynamometer display real-time performance parameters so that the engine control parameter tuning and multi-objective optimization rules can be integrated and the engine performance be verified at the same time by dynamometer experiments. This study has built the fuel consumption and pollution models of vehicle driving cycle which then was converted into engine torque and speed by using the real vehicle parameters. Several key points were sorted from the corresponding map data for steady state estimation measurement. The selected key points control parameters were changed to reduce the overall exhaust emissions.