Preliminary Research of Environmentally Friendly Taxi Based On Comprehensive Evaluation In Macau SAR

Transcription

1 Applied Mechanics and Materials Vol. 192 (2012) pp (2012) Trans Tech Publications, Switzerland doi: / Preliminary Research of Environmentally Friendly Taxi Based On Comprehensive Evaluation In Macau SAR Lap Mou TAM 1, a, Pak Kin WONG 2,b, Hangyuan LAO 3,c and Zhengchao XIE 4,d Department of Electromechanical Engineering, Faculty of Science and Technology University of Macau Macao, China a fstlmt@umac.mo, b fstpkw@umac.mo, c mb15502@umac.mo, d zxie@umac.mo Keywords: Vehicle emission, Environmentally friendly taxi, Management Abstract: To promote the green taxis in Macau SAR has being attractive because of the increasingly air pollution caused by vehicles emission. In order to improve the air quality and living condition in Macau, this paper shows us some environmentally friendly taxis to replace theconventional ones. In this paper, an overall picture of the current situation and tendency of world s taxies is firstly presented. Secondly, the vehicle emissions of Macau taxi including environmentally friendly ones are detailedly demonstrated and compared. On the basis of feasibility, cost, safety and regulations related to Macau, the existing vehicle models are also comprehensively elaborated and evaluated. At the end of the paper, it will predict possible directions of the development of taxis in the near future of Macau. The analysis and evaluations of vehicle models are all considerate of what really Macau is. Introduction Macau is a popular tourist destination in Asia and has been a place of importance in history. The development in transportation has led to better connectivity and easy access to Macau. The travel in Macau has also been improved in the last century and taxi service offer good service catering to tourists coming from different parts of the world [1]. Although playing an important role in Macau public transportation, the taxis are also becoming a fatal source of tail gas emission. As a consequence, promoting the environmentally friendly taxi is not only to improve the green city image, but also to create a green living space for every one in Macau. Meanwhile, with the increasing number of city population and taxis, taxi operators and the local government are making great efforts to figure things out such as city air quality improvement, noise reduction and traffic congestion control etc [2]. What s more, numbers of lower carbon-emission vehicles have emerged along with the development of vehicle technology. In the United States and Canada, the most common taxi car is Ford Crown Victoria which offers a spacious interior and V8 engine, but is slowly being phased out by both taxi companies and car manufactories with the popularity of more fuel efficient and hybrid taxis such as Toyota Camry hybrid, Toyota Prius hybrid, Ford Escape hybrid and Honda Civic hybrid especially in Toronto and North America [3]. In some cities of mainland China, such as Hangzhou and Shenzhen, pure electric vehicle taxi fleets have been running on a trial in order to improve the city air quality, and city like Chongqing, has been used the CNG taxis for several years. With respect to Macau, the current taxis are all equipped with diesel engines which are more powerful and higher fuel efficiency than gasoline engines, however, with a disadvantage of higher diesel price in Macau area. Furthermore, it always consumes more fuel and needs adequate power to climb the steep hills because of the island terrain, meanwhile, the smoky emission is still belching out day and night. For these reasons, this paper will firstly demonstrate the emissions of current taxis compared with others, and then review and evaluate different possible vehicle types according to their feasibilities, economy, safety and regulations in Macau SAR. Finally, it will predict possible directions of the development of taxis in the near future of Macau. All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP, (ID: /07/12,04:22:42)

2 446 Advanced Mechanical Engineering II Current Taxi Types and Vehicle Emissions Comparison Current taxi types. Most taxis in Macau are Toyota Corolla which is powered by a 2.0 liters diesel engine with 89 horsepower maximum output and 215 Newton meter maximum torque, and with a 289 liters trunk capacity [4]. The other taxis range from economic Japanese cars to luxury German cars, but all of them are fully dependent on fossil fuel. As a consequence, the air pollution will keep increasing with the number of taxis and travelling cost will rise up with the higher oil price. According to statistics, the number of Macau taxi goes up from 780 in year 2005 to 980 in year 2011, and the predicted number in year 2013 is 1180 or more. Moreover, the pricing starts at city taxi is forced to ascend with the global oil price, which was only 11 MOP before September, 2008 and will reach 15 MOP after April, 2012 [5]. Vehicle emission & consumption comparison. Nowadays, more and more car manufacturers are working on hybrid vehicles and alternative fuel technologies so as to reduce the emission and to get rid of fossil fuel gradually. Four example of environmentally friendly vehicles should be mentioned below. Compared with the conventional internal combustion engine vehicles, the emission and consumption of the other four representative vehicles can be seen from table 1 [6], and the European 5 emission standard can be seen from table 2 [7]. Table 1: Vehicle emissions & consumption comparison CO 2 CO NO x HC Combined Fuel consumption [L/100km] Noise level [db] Toyota Corolla a (2.0D-5D) Toyota Prius b (1.5VVT-i) Honda Civic GX c (1.8SOHCi-VTEC) f 70 Honda Civic d (1.8 i-vtec euro5) Honda accord e (2.2 i-dtec euro5) a Toyota Corolla is the most common taxi car in Macau, it is powered by a 2.0litre diesel engine but can only fit the third European emission standard. b Toyota Prius is the first commercial hybrid electric vehicle in the world, it is equipped with 1.5litre VVT-i(Variable Valve Timing-intelligent) gasoline engine. c Honda Civic GX has equipped with a 1.6 liter In-line 4 cylinder natural gas engine. d Honda Civic model year 2010 has equipped with a 1.8 liter i-vtec(intelligent-variable Valve Timing and Lift Electronic Control) gasoline engine which can fit the euro 5 emission standard. e Honda accord model year 2010 has equipped with a 2.2 liter i-dtec diesel engine which can also fit the euro 5 emission standard. f Equivalent fuel consumption in heating value. Table 2: The European 5 emission standard Emissions CO NO x HC PM Light diesel engine Light gasoline engine

3 Applied Mechanics and Materials Vol Classifications and Comprehensive Evaluations on Models for Environmentally Friendly Taxis 1)Full hybrid electric vehicle(fhev). 1a)basic principle. Generally speaking, HEV is a vehicle in which propulsion energy is available from two or more kinds or types of energy stores, sources or converters and at least one of them can deliver electrical energy. Based on this there are many types of HEV, however, here we discuss the HEVs which have ICEs (internal combustion engines) and electric motors in their drive train. To speak more precisely, Toyota prius, the vehicle model used in this paper, is a series/parallel HEV whose configuration incorporates the features of both the series and parallel HEVs, but involves an additional mechanical link (Planetary Gear) compared with the series hybrid and also an additional generator compared with the parallel hybrid that make them more complicated and costly, as shown in Fig. 1 [8]. Fig. 1: Drive train configuration of a series/parallel HEV 1b)vehicle cost & fuel economy. In March, 2012, the latest model of Toyota Prius C hybrid was released globally and hatched at $23,990(approximately 192,000MOP of Manufacturer's Suggested Retail Price, 250,000MOP of total price), and the total wholesale price of Toyota Corolla 2.0D-5D is about 19,5000 MOP. When taking the fuel consumption into consideration, Prius has a 1.5 liter per 100 kilometer fuel economy compared with Corolla, and the user can save 23MOP or so per 100 kilometer when calculated with the latest oil price in Macau. Suppose that every taxi in Macau runs at a distance of 450 kilometer per day, and it can save nearly 38,000MOP every year [9]. With the increasing global oil price, it will be more economical to drive a hybrid vehicle than a conventional ICE vehicle. 1c) strength & opportunity. Full HEV s engine can operate at the most efficient point at each speed of operation and can utilize the energy from the regenerative braking and the down slope driving, so the fuel efficiency improves and the carbon emission is less than the other vehicles. In addition, because of the smaller ICE in a Full HEV, the vehicle body will be more compact, more flexible and lighter. With the help of electric motor, the acceleration becomes quiet and smooth. 1d) weakness & threat. Hybrids require larger batteries than conventional ICE vehicles. Mining and smelting the metals, together with making and recycling the batteries results in much higher environmental loadings than those for conventional ICE vehicles. Moreover, the lifetime of ultra-battery is much less than a conventional vehicle although it has a warranty for 2 years or 50,000km. The engine volume cannot fulfill the specified value (2.0 liter at least) in Macau law 1. 2) Euro 5 standard gasoline & diesel vehicle. 2a) basic principle. To maintain the climate protection policy, the Kyoto Protocol, and to limit the vehicle emissions, the European Commission enacts a new legislation every four years for newly registered automobiles since Low emission vehicle has a high quality request to its fuel 1 Specified by Department of Service and Affairs of Transportation: Engine volume of new taxi should be 2.0 liters at least and the trunk space should be easily to hold at least two suitcases of 80cm 60cm 25cm, equal to 240 liters [12].

4 448 Advanced Mechanical Engineering II supplied, and so as to its engine design technology. To comply with the emission standard especially with the NO x standard, various technical solutions are developed by automobile engineers such as exhaust gas recirculation (EGR) systems, selective catalytic reduction (SCR) systems, lean NO x traps (LNT) and so on [10]. Fig. 2: Honda Civic Sedan 1.8 i-vtec 2b) vehicle cost & fuel economy. The Manufacturer's Suggested Retail Price of Honda Civic 1.8 ranges 144,000MOP to 160,000MOP, given a lot of credit to the smaller engine displacement. Calculated with the local gasoline price of 12.7MOP per liter and light diesel oil price of 13.4MOP/L (updated to 20/3/2012), the diesel vehicles can save nearly 20,000MOP per year of oil consumption than the gasoline ones, but cost nearly 20,000MOP per year than the hybrid ones. 2c) strength & opportunity. Technically, conventional ICE vehicles can meet the emission standards by modification or adding SCR systems. Actually, the new type of low emission vehicles (LEV) is becoming cheaper and popular. What s more, the higher fuel quality, the longer engine lifetime, and the lower maintenance cost. They are likely to fulfill the regulations of Macau. 2d) weakness & threat. The biggest problem of European 5 standard emission vehicles is high price of high quality fuel and the supply guarantee. And they are still full dependent on fossil fuel. 3) Compressed natural gas vehicle and its hybrid with fossil fuel. 3a) basic principle. Honda Civic GX, as shown in Fig. 3 [11], is a model of Natural Gas vehicle and is a living proof that we have alternatives to the dependence of fossil fuel. Extensive research by Honda lead to a CNG dedicated engine designed for optimized performance on natural gas. Features of the vehicle include an increased compression ratio of 12.5:1 for low energy density of natural gas and decreased trunk space for the huge natural gas tank. Fig. 3: Honda Civic GX 3b) vehicle cost & fuel economy. The suggested starting price of Civic GX is more than 210,000MOP, and it is a bit more expensive than conventional one. However, 3 equivalent liters gasoline consumption per 100 kilometer makes the Civic GX to be an ultra-low emission vehicle (ULEV), which is equal to about 2.65 cubic meter natural gas at room temperature and ambient pressure. Assume that the vehicle natural gas price is 5 MOP per cubic meter, it only takes 60 MOP every day and can save nearly 100,000MOP than Corolla every year. 3c) strength & opportunity. The natural gas gaining popularity of as vehicle fuel due to following important factors (i) CNG has higher octane number and lower cetane number which makes it superior fuel than gasoline, (ii) it is more economical as compared to petrol or diesel due to its vast reserves and low production cost, (iii) operating and maintenance costs are much lower than the fossil

5 Applied Mechanics and Materials Vol fuelled vehicles, (iv) natural gas vehicles reduces air pollution significantly lower than conventional fuel running vehicle, (v) CNG does not contain lead or benzene, thus eliminates lead fouling of spark plugs and lead or benzene pollution [13]. 3d) weakness & threat. There is not adequate trunk space for passengers suitcases because of the huge gas tank. Thirdly, the construction of CNG refuelling station takes time and cost much. 4) Liquefied petroleum gas vehicle and its hybrid with fossil fuel. Because the density of LPG in room temperature and pressure is greater than the air and LPG is inflammable which will cause blast easily. In such a high population density region, we do not take the LPG taxi into consideration for safety. Conclusion Comprehensive evaluation of typical environmentally friendly vehicle models discussed in this paper showed their advantages and disadvantages in emission values, fuel economy, operational performance and security. CNG vehicle is the most energy economic one among these models except its charging facility construction, and it also seems no promising for LPG taxi car in Macau because of its insecurity. Finally, the Full HEVs and the European 5 standard vehicles seem to be better choices to be Macau taxi during the next decade. Reference anyucika [1] /macau-taxi-service.html [2] "Taxi 07 Roads Forward", page 135 [3] [4] [5] [6] [7] [8] Edward W C LO, Review on the Configurations of Hybrid Electric Vehicles, 3rd International Conference on Power Electronics Systems and Applications, [9] Lester B. Lave, Hearther L. MacLean, An environmental-economic evaluation of hybrid electric vehicles: Toyota s Prius vs. its conventional internal combustion engine Corolla, Transportation Research Part D 7 (2002) [10] Manuel Frondel, Christoph M. Schmidt, Colin Vance, A regression on climate policy: The European Commission s legislation to reduce CO2 emissions from automobiles, Transportation Research Part A 45 (2011) [11] [12] [13] Olivier Bordelanne, Micheline Montero, Frédérique Bravin, Anne Prieur-Vernat, Olga Oliveti-Selmi, Hélène Pierre, Marion Papadopoulo, Thomas Muller, Biomethane CNG hybrid: A reduction by more than 80% of the greenhouse gases emissions compared to gasoline, Journal of Natural Gas Science and Engineering 3 (2011)