02-05-2013, 02:03 PM
HYBRID VEHICLES
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INTRODUCTION
The main problem the world is facing is environmental pollution. The major reasons for the pollution are industrialization, burning of fossil fuels, internal combustion engines etc. Many problems are being faced due to the usage of fossil fuels. Some of these problems are Global Warming, Toxic Emissions, Drilling and Transport of fossil fuels, Dependence on Foreign Oil. In order to overcome the problem of pollution, many alternative methods are in developing stage. Among these some of them are solar energy, Fuel cells, Electric vehicles, Hybrid vehicles.
The world started down a new road in 1997 when the first modern hybrid electric car, the Toyota Prius, was sold in Japan. Two years later, the United States saw its first sale of a hybrid, the Honda Insight. These two vehicles, followed by the Honda Civic Hybrid, marked a radical change in the type of car being offered to the public: vehicles that bring some of the benefits of battery electric vehicles into the conventional gasoline powered cars and trucks we have been using for more than 100 years. In the coming years, hybrids can play a significant role in addressing several of the major problems faced by the United States and the world today: climate change, air pollution, and oil dependence. Whether this new technology delivers on its promise hinges on the choices automakers, consumers, and policymakers make over the coming years. Poor choices could result in hybrids that fall short even of what conventional technology could deliver on fuel economy, emissions, or both. If they are designed well, these hybrids can equal or better the utility, comfort, performance, and safety we’ve come to expect, while saving us thousands of dollars at the gas pump.
DEFINITION
Hybrid vehicle consists of engine with at least 2 different energy converters and 2 different energy sources for the vehicle propulsion. Hybrids have been defined in a variety of ways, few of which help in determining whether a particular model realizes the technology’s potential.
THE HYBRID TECHNOLOGY POTENTIAL
The Honda civic hybrid and Toyota prius are good examples of current potential of hybrids but they are just start. More technology is ready to be put to work and only for compact cars. This study provides a broader picture of how hybrid could transform the whole passenger fleet both within this decade and in next. Even conventional technologies could boost the passenger vehicle fleet average up to 40msg.and all the hybrid examined in this study can meet today’s most stringed standards for tailpipe emissions (excluding the emission standards).
THE HISTROY OF HYBRID VEHICLES
Automotive hybrid technology became widespread beginning in the late 1990s. The first mass-produced hybrid vehicle was the Toyota Prius, launched in Japan in 1997, and followed by the Honda Insight, launched in 1999 in the United States and Japan. The Prius was launched in Europe, America and the rest of the world in 2000. The first generation priussedanhas an estimated fuel economy of 52 miles per US gallon (4.5 L/100 km; 62 mpg-imp) in the city and 45 miles per US gallon (5.2 L/100 km; 54 mpg-imp) in highway driving. The two-door first generation Insight was estimated at 61 miles per US gallon (3.9 L/100 km; 73 mpg-imp) miles per gallon in city driving and 68 miles per US gallon (3.5 L/100 km; 82 mpg-imp) on the highway.
The Toyota Prius sold 300 units in 1997, 19,500 in 2000, and cumulative worldwide Prius sales reached the 1 million mark in April 2008.By early 2010, the Prius global cumulative sales were estimated at 1.6 million units. Toyota launched a second generation Prius in 2004 and a third in 2009.The 2010 Prius has an estimated U.S. Environmental Protection Agency combined fuel economy cycle of 50 miles per US gallon (4.7 L/100 km; 60 mpg-imp).
Hybrid Structure
Having a proper organizational structure is essential for companies belonging to all sectors of the economy to make progress on the business front. A well planned organizational structure can lead to increased efficiency and this will reflect on the revenue and profits of the firm. Among the different types of organizational structures is a hybrid organizational structure. It has been defined as the combination of the divisional as well as the functional structures. A hybrid organizational structure has all the advantages of these structures. knowing what is a hybrid structure is possible only when you know the meaning of divisional and functional structures separately.
Divisional organizational structure
The divisional organizational structure has many teams which are entirely focused on development of a single product. the best example of such a structure can be a car company which sells cars with different names. concentration on a single product can help the company achieve perfection and better results. however, the drawbackof this structure is that competing with divisions in the same company can lead to conflicts and office politics, which can affect the total output.
SERIES PARALLEL HYBRID VEHICLE
The series-parallel hybrid system uses an electric motor to drive the vehicle at low loads and low speeds and the gasoline engine when loads and speeds increase. The electric motor and the gasoline engine can work individually, or together, depending on the power required to drive the vehicle. In addition, as the system drives the wheels, the combustion engine drives a generator to simultaneously generate electricity to recharge the battery when necessary.
A control unit determines the best balance of engine and electric power to achieve the most efficient vehicle operation. The combustion engine operates within its most efficient range resulting in a vehicle that reduces exhaust emissions by 80% to 90% compared to conventional vehicles. It also produces about half the amount of carbon dioxide. The electric motor uses power from a high voltage battery, which is charged by the internal combustion engine, and by reclaiming the waste energy of decelerating or braking.
SERIES/PARALLEL DIVETRAIN
A series-parallel hybrid combines the efficiencies and complexities of both types of systems. The ICE and electric motor are combines both mechanically and electrically.These systems are that it can act like both a series and parallel system depending on the driving conditions. At high speeds the system will function in parallel, routing power from the engine directly to the wheels, where the engine can run near its highest efficiency. In slow or stop-and-go conditions the system will run in series, routing power from the engine to the generator to the motors, allowing it to run at its highest efficiency. Therefore, this is the most fuel efficient design.
Power-split hybrid or series-parallel hybrids are parallel hybrids. They incorporate power-split devices allowing for power paths from the engine to the wheels that can be either mechanical or electrical. The main principle behind this system is the decoupling of the power supplied by the engine (or other primary source) from the power demanded by the driver.
A combustion engine's torque output is minimal at lower RPMs and, in a conventional vehicle, a larger engine is necessary for acceptable acceleration from standstill. The larger engine, however, has more power than needed for steady speed cruising. An electric motor, on the other hand, exhibits maximum torque at standstill and is well-suited to complement the engine's torque deficiency at low RPMs. In a power-split hybrid, a smaller, less flexible, and highly efficient engine can be used. The conventional Otto cycle (higher power density, more low-rpm torque, and lower fuel efficiency) is often also modified to a Miller cycle or Atkinson cycle(lower power density, less low-rpm torque, higher fuel efficiency). The smaller engine, using a more efficient cycle and often operating in the favorable region of the brake specific fuel consumptionmap, contributes significantly to the higher overall efficiency of the vehicle.
Addition of a fixed gear second planetary gear set as used in the Lexus RX400h and Toyota Highlander Hybrid. This allows for a motor with less torque but higher power (and higher maximum rotary speed), i.e. higher power density.The Two-Mode Hybridname is intended to emphasize the drive-train's ability to operate in all-electricas well as hybrid (Mode 2) modes.