Advantages And Disadvantages Of Hybrid Cars Engineering Essay

Advantages And Disadvantages Of Hybrid Cars Engineering Essay Even by recently introducing hybrid vehicles to the worldwide transportation system, the need to reduce transport generated CO2 emissions is still a matter of high significance. One promising and at the same time environmentally friendly solution in terms of limiting the greenhouse gas (GHG) emissions is considered to be the introduction of hybrid electric vehicles (HEVs). In this technical report HEVs will be compared to conventional internal combustion engine vehicles (ICEs) and battery electric vehicles (BEVs), by surveying their technical characteristics and performance, their total cost of ownership (TOC) and their GHG and air pollution (AP) emissions. HEVs can be classified either as parallel or series due to differences at their powertrain configuration. They both use an electric motor and an engine but only parallel HEVs can use simultaneously either of them as a main power source. At series HEVs the engine charges an on-board battery unit that transmits power to the electri c motor. Reduced engine capacity, regenerative braking ability and engine shut-off capability are the main discernible characteristics of HEVs in confrontation to their equivalent conventional models.1Some of the most generally acceptable advantages of the HEVs are their low local emissions combined with a high fuel economy, the long driving range and their commercial availability but they still depended on fossil fuels and they are more expensive than conventional ICEs.2 Technical characteristics and performance Vehicle efficiency and primary energy efficiency, or otherwise well-to-wheel efficiency are the measures used in this study to compare those different drivetrain vehicles. We define the Vehicle efficiency: and, the Primary efficiency where = the useful energy at the wheels, = the energy supplied to the vehicle and = the primary energy.3 Hybrid Electric Vehicle (HEV): For both parallel and series HEVs the vehicle efficiency is 29%. Internal Combustion Engine Vehicle (ICEV): The max efficiency ay ICEs is achieved near the max load point. The mean efficiency is relatively low since no max power can be achieved in normal driving conditions. At mean required power of 10kW the efficiency is low around 18% whereas around 60-90kW reaches up to 35-40%.4 Battery Electric Vehicles (BEV): An electric motor, connected with a generator and a system of transmission forms the main function of BEVs. Due to the development of advanced electronic control systems, the mean energy efficiency over a normal drive schedule has increased both for generators and electric motors.5 The potential vehicle efficiency is 61%. The difference in efficiency between hybrid and conventional vehicles can be partly justified by the use of Atkinson-cycle in the hybrid vehicle engines instead of the Otto cycle in the ICEs.6 In cases where the Atkinson cycle is applied to a well modified Otto cycle engine it results to high fuel economy that can be explained by the lower per displacement power than the traditional ICE four stroke engine. When more power is needed, an electric motor can supplement the engine power which is the basis of an Atkinson cycle working hybrid-electric drivetrain. Bigger work output and higher thermal efficiency than the Otto cycle while operating under similar conditions leads to higher primary efficiency in HEVs.7 In terms of acceleration, BEVs are better than both HEVs and ICEs but in high speed performances ICEs are faster than HEVs with BEVs to be the slowest.8 Total Cost of Ownership The total cost of ownership is by estimation the sum of the purchase price (Components, retail margin, battery, initial on-road costs), the operating costs (fuel, electricity, servicing) and the resale value. The purchase price is fixed for each vehicle (excluding the uncertainties in the battery prices) but in order to define the operational cost we first have to settle a representative drive cycle. In this study we will work with the AUDC (Australian Urban Drive Cycle) which is a bit more intense in the driving behavior than the common ones but still close to the NEDC (new European drive cycle) and the ARTEMIS cycle (150000 km travelled per vehicle lifetime) .9,10 Due to the large uncertainty in the vehicle battery prices we took a baseline value of $800(kWh)-1 or $16.800 [brooker,4] Furthermore, we estimated a base fuel price at $1.4 L-1 as well as a base electricity price at $0.175 kWh-1.11 In order to determine the operational cost of each vehicle we need to define the fuel and electricity consumption of our modeling vehicles. For a Class E parallel HEV the fuel consumption in L/km was calculated 5.7 whereas for the same category the CV had a consumption of 9.4 L/km. The electricity consumption of a Class E BEV is 0.11 kWh/km. It is clear that despite the entailed increase in vehicle electrification in the purchase price it is compensated with a decrease in the operational costs. Only by comparing each vehicles purchase price, the CV is the most cost effective solution of both HEVs and BEVs with the lasts to be the most costly ones mainly because of the high battery costs. On the other hand even though the BEVs have the lower running costs it is shown that the parallel HEVs are the ones with the lower Net Present value. Finally in a recent study it was suggested that even hybrid cars are a quite more expensive than the conventional ICE vehicles thay may reduce fuel consumption by 34-47% compared to them which decreases their NPV even more.12 Environmental evaluation In order to determine the environmental impact of each vehicle we will examine their air pollution and greenhouse gas emissions. To estimate the total CO2 emissions we use the product of carbon intensity (CO2e/MJ) by fuel producers, energy intensity (MJ/km) by car producers and demand (km) by car drivers. In Hybrid (gasoline) vehicles the CO2 emissions are 20 gCO2/MJ and 220 gCO2/MJ delivered to vehicle wheels during production and vehicle life cycle respectively. In ICEs the emissions during production and life cycle are 50 gCO2/MJ and 300 gCO2/MJ whereas in BEVs (electricity production from coal) are 320 gCO2/MJ and approximately 0 gCO2/MJ respectively. It is interesting to notify that in case were electricity production comes from renewable sources (wind) the emission at the production stage of BEV are almost defeasance.13,14 Table1 Environmental impact associated with vehicle production stages Type of car GHG emissions (kg) AP emissions (kg) Conventional 3595.8 8.74 Hybrid 4156.7 10.10 Electric 9832.4 15.09 In both HEVs and BEVs we must also consider the environmental impact of batteries. We assume that both vehicles use NiMeH batteries of 53kg (1,8kWh capacity) and 430kg( 27kWh capacity), respectively. The production of those batteries require 1.96MJ of electricity and 8.35MJ of liquid petroleum gas.15 With those data and considering that the number of batteries per life of vehicle is 2 for hybrids and 3 for electrics, the total GHG emission per life of vehicle are more than 12 times higher in BEVs. Finally in order to compare the total GHG and AP emissions for ICE, BEV and HEVs we will consider the scenario that electricity is produced only from renewable energy sources. In that case ICE vehicles are the most polluting ones with almost double GHG and AP emissions than hybrid vehicles and 10 times more than BEV vehicles (450/235/40 g CO2,equivalent /mile respectively).16 Table2 Total environmental impact for different vehicles Car Type GHG emissions(kg) /100 km of travelling AP emissions(kg) /100 km of travelling Conventional ICE 21.4 0.0600 Hybrid HEV 13.3 0.0370 Electric BEV 2.31 0.00756 The average travelling distance during a 10 year vehicle life time is 241,350km.17 We must say here that in any scenario for electricity production the BEV are still the most environmentally friendly vehicles. Furthermore, hybrid cars may reduce Well-to-wheel GHG emissions to 89-103 gCO2 comparing to conventional ICE gasoline vehicles.18 Georgios Fontaras, Panayotis Pistikopoulos, Zissis Samaras, 2008, Experimental evaluation of hybrid vehicle fuel economy and pollutant emissions over real-world simulation driving cycles, Atmospheric Environment 42, 2008, 4023-4035. C.C.Chan, Fellow, IEEE, Alain Bouscayrol, Member, IEEE, and Keyu Chen, Member, IEEE, 2010, Electric, Hybrid, and fuel-Cell Vehicles: Architectures and Modeling, IEEE transactions on vehicular technology, Vol.59, No.2, February 2010. Max Ahman, 2000, Primary energy efficiency of alternative powertrains in vehicles, Energy 26, 2001, 973-989. Ecotraffic, The life of fuels, Stockholm, 1992 Kopf et al, 1997, development of a multifunctional high power system: meeting the demands of both a generator and traction drive system, Electric Vehicle Sympozium 14, Orlando (FL), 1997. Yingru Zhao, Jincan Chen, 2006, Performance analysis and parametric optimum criteria of an irreversible Atkinson heat-engine, Applied Energy 83,2006, 789-800. Shuhn-Shyurng Hou, 2006, Comparison of performances of air standard Atkinson and Otto cycles with heat transfer considerations, Energy conversion and Management 48, 2007, 1683-1690. Martin Eberhard and Marc Tarpenning, 2006, The 21st century electric car, Tesla Motors Inc. Michel Andrà ©, 2004, The ARTEMIS European driving cycles for measuring car pollutant emissions, The Science of the total environment, 334-335, 2004, 73-74. R.Sharma, C.Manzie, M.Bessede, M.J.Brear, R.H. Crawford, 2012, Conventional, hybrid and electric vehicles for Australian driving conditions Part 1: Technical and financial analysis, Transportation Research Part C: Emerging Technologies, 25, 2012, 238-249. Annual energy outlook 2012 with projections to 2035, 2012, U.S. energy information administration, June 2012. Oscar P.R van Vliet, Thomas Kruithof, Wim C. Turkenberg, Andre P.C. Faaij, 2010, Techno-economic comparison of series hybrid, plug in hybrid, fuel cell and regular cars, Journal of Power Sources, Vol.195, Issue 19, 2010, 6570-6585. Felix Creutzig, Emily McGlynn, Jan Minx, Ottmar Edenhofer, 2011, Climate policies for road transport revisited (1): Evaluation of the current framework, Energy Policy, 39, 2011, 2396-2406. Mikhail Granovskii, Ibrahim Dincer, Marc A.Rosen, 2006, Economic and environmental comparison of conventional, hybrid, electric and hydrogen fuel cell vehicles, Journal of Power Sources, 159, 2006, 1186-1193. M.Rantik, 1999, Life Cycle Assessment of five batteries for Electric vehicles under different charging regimes, report, KFB-Stockholm, 1999. Tien Nguyen Jake Ward, 2010, Well-to-Wheels Greenhouse Gas Emissions and Petroleum Use for Mid-Size Light-Duty Vehicles, US department of energy, Program Record (Offices of Vehicle Technologies Fuel Cell Technologies), 2010. United States Department of Energy, Energy Efficiency and renewable energy. Via www.fueleconomy.gov , accessed May 15, 2005. G.J.offer, D.Howey, M.Contestabile, R.Clague, N.P.Brandon, 2010, Comparative analysis of battery electric, hydrogen fuel cell and hybrid vehicles in a future sustainable road transport system, Energy Policy, 38, 2010, 24-29.

Construction resources Essay

Construction resources make use of physics in many of their products. Two that I have picked are solar collectors and their use of insutation. Insulators have the purpose of preventing conduction, convection and radiation to unwanted areas. There are a wide range of techniques and materials used in doing this and I am going to look in depth at this idea. The company uses solar collectors in many different ways, their main purpose is to collect solar energy and heat energy. They can be used to heat and power many different appliances. Photovoltaic cells: Photovoltaic cells transfer the energy carried by the electromagnetic waves that make up sunlight directly to an electrical circuit in order to make a current flow. Light excites electrons to move from one layer to another through semi conductive silicon materials. Only a fraction of a volt is produced so a large array is needed to produce appreciable currents, usually about 20W to 100W. The Photovoltaic cells produce DC current so if alternate current AC is desired then an inverter is required. AC form is commonly available from the mains. Solar cells: Sunlight may also be used to heat water directly. This can be done in two ways, water can be circulated through pipes which run through the back of the solar cells, producing water at around 60oC suitable for household use. The other method is to focus sunlight from a large are to a small spot using an array of mirrors, this can produce temperatures of up to 4000oC and it’s quite feasible to produce power stations from this, however it has not been implemented yet. Here is on way in which the hot water can be used, this is quite economical and environmentally friendly. Solar panels are quite versatile and can be put on many roofs of simply in the garden, which makes them popular when it comes to heating swimming pools of hot water for showers. Any material that is a poor conductor of heat and electricity can be used as an insulator. Thermal insulating materials reduce the flow of heat between hot and cold regions. Thermal insulation may have to fulfill one or more of three functions: to reduce thermal conduction in the material, in which heat is transferred by electrons; to reduce thermal convection currents, which can be set up in air- or liquid-filled spaces; and to reduce radiation heat transfer, in which thermal energy is transported by electromagnetic waves. These are three ways in which heat energy can be transferred. Conduction, where heat energy is transferred through solid materials, metals are normally the best conductors. There are a number of factors that affect thermal conductivity. Increasing the area of the cross-section of the solid through which hear flows increases the rate of flow, however increasing the thickness of the wall decreases the flow of heat. Provided that a steady state has been reached (where the temperature of any point is not changing through time) then the rate of flow of heat ? Q/? t is given by: ?Q/? t –> A ? T/? x Besides the physical dimensions of the materials, another factor affecting rate of flow is the properties of the material, the Thermal Conductivity of the materials ? through which the heat energy is travelling is the constant of proportionality in this relationship, so:?Q/? t = -? A ? T/? x The units for thermal conductivity are watts per metre per kelvin. The Quantity ? Q/? t is called the temperature gradient. On my visit to Construction resources I noticed that they have used these Physical conclusions in there insulation. One in particular is ‘Homatherm’ a wall and roof insulator. The slabs are thick which means less flow of heat, and have a thermal conductivity is only 0. 04 W/mK. Conduction in terms of particles: The particles in metals and non-metals are arranged differently, which gives them their different characteristics. In a non-metal the particles have forces between them that can be described like springs. When heat is delivered to the solid the oscillations of the particles being heated will increase in amplitude. For heat to be conducted the neighboring particles must also receive the extra energy, as particles oscillations increase in frequency the neighboring particles also gradually increase in frequency as heat is transferred to them. This is a very slow process. In a metal the arrangement is different, metallic boding occurs between metal atoms where a ‘sea of delocalized’ electrons hold the positive metal ions together in a lattice. It is these free electrons that are responsible for the high conductivity character of metals. When a metal is heated the metals ions vibrate with an increase frequency. When an electron hits these ions with extra energy, they receive this extra energy and move faster. This electron can then travel to another parts of the lattice, to an ion that hasn’t received any of this heat energy and collide with it, transferring its energy to this ion. Now that ion has extra energy and vibrates with a greater frequency. This process is a lot faster as there are many electrons in a metal lattice. U-Values: Architects and heating engineers use U-Values to calculate the flow of heat energy through building materials. The U-Values is quoted for a given thickness of a particular material, and is based on actual measurements made using the material. The U-Value is defined as: U-value = Rate of energy flow Area X Temperature difference Construction resources uses this knowledge of U-Values when designing building materials to reduce the energy wasted in the form of heat going out of the build and to achieve the ultimate goal of reducing CO2 emissions. But there are obvious limitations with reducing thermal conductivity, you can only reduce it to a certain amount, 0. 025 in air, so there will always be heat loss. Also too much insulation in the house will lead to what construction resources refers to as internal pollution. This has lead to construction resources researching in trying to lower the energy that is used to build and transport he construction materials. Bibliography: Microsoft Encarta Heinemann Advanced Science Salter’s Horner’s AS Advanced Physics Strengths and Limitations of Photovoltaic cells: Since one photovoltaic cell only produces a small fraction of a volt, large arrays are required to produce appreciable voltages. This requires a lot of space and the cells need to be in a place where no shadows will be cast on them. This limits what they can be used for. Also the amount of power produced by the photovoltaic cells directly depends on the amount of sunlight, so they cannot be relied on to produce power for something that constantly needs it. The only way this can be overcome is if some power was stored for a rainy day. But this again would take up space. Also an array of solar collector will be expensive and have a long ‘pay back’ time. However it is environmentally friendly and after the pay back time, savings can be made. Also photovoltaic cells can be made look attractive depending on where they are placed. Strengths and Limitations of solar cells: The solar cells have similar limitations to the photovoltaic cells in regards to positioning and cost but a small array is only required to produce enough hot water for something like residential showers or central heating. This is economical and environmentally friendly and solar cells are quite versatile.

How Will Science and Technology Change Our Lives Essay

The Contribution of India to the world of Science & Technology dates back to ancient times. India had the best of the scientists in different fields of science and technology – mathematics, medicine, architecture, astronomy, geometry, chemistry, metallurgy, etc. Aryabhatta was a fifth century mathematician, astronomer, astrologer and physicist. He introduced the concept and symbol for Zero and the decimal place value system to the world of mathematics. Bhaskaracharya introduced Chakrawat Method or the Cyclic Method to solve algebraic equations. Kanad, a sixth century scientist developed the atomic theory which says that the material universe is made up of anu/atom, which cannot be further subdivided and they are indivisible and indestructible. This is what the modern atomic theory says. In the field of medicine, India was a front runner. Susruta was a pioneer in the field of surgery. Charak, considered the father of ancient Indian science of medicine, was the first to talk about digestion, metabolism and immunity as important for health and so medical science. The science of Yoga was developed in ancient India as an allied science of Ayurveda for healing without medicine. India was a pioneer in many technologies such as metallurgy (steel making, iron, zinc, bronze etc) and Architecture. The findings in Moganjatharo civilisation stand testimony to this fact. The structures such as Iron Pillar in Delhi, Taj Mahal, Gol Gumbaz, Mahabalipuram, Tanjore Periya Kovil are some examples of India’s supremacy in the Architecture. Science and Modern India Indian scientists have played a stellar role in the development of India. In the short span of its post-independence history India has achieved several great scientific achievements. Indian scientists have proved their mettle in the face of international sanctions and have made India one of the scientific powerhouses of the world. Sir M. Visvesvaraya, Sir CV Raman, Jagadish Chandra Bose, Subramaniam Chandrasekar, Srinivasa Ramanujam, Homi Bhaba, Vikram Sarabhai are some of the names leading the pack of Indian scientists. How technology impacts people’s life? Technology affects people’s lives by improving medicines, provides better treatment for diseases and insures a longer life. It improves transportation by helping people move from one corner of the world to other in hours by using transportation services such as Airways, Railways, or even Bus Transportation. Modern Technology changed people’s lifestyle and the way they live. For example, now it’s possible to surf Internet on TV, watch programs, pause Live TV, and even playback live shows. Internet surfing is a technology revolution. Because of that technology, a person could know what is happening on the other side of the world. Due to Internet, it is now possible to say that the world is at your fingertips. Recent discoveries and scientific breakthroughs such as Cracking the DNA code and Mapping the Genome may completely change the way people look even before they are born. Diseases that are passed through generations, like diabetes, chronic diseases may be eliminated from the unborn child. What India should do? While India is uniquely positioned to use technology for progress, it has in the recent past lagged behind in the quality and spread of science research. The need for a strong science eco-system based on a sound research foundation is the need of the hour for India to become a Global Power house. The key to continued success for India in a globalised knowledge-driven economy is building a higher education system that is superior in quality and committed encouragement of relevant research in science and technology. To achieve this, the government, universities, companies, venture capitalists, and other stakeholders should come together to enable Research and Development to achieve superiority in the field of science and technology.

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