08-16-2017, 09:52 PM
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ABSTRACT
Automobiles as we know today are very complicated machines even though their basic purpose is transportation. The fundamental processes that a car performs are acceleration of wheel speed, their control through braking, the turning of the wheels with the help of the steering mechanism & so on.
The name symbolizes the combination of hydrogen as fuel for the fuel cell propulsion system. The replacement of conventional mechanical and hydraulic control linkages for steering, braking and other control systems by a drive-by-wire system. By combining fuel cell and by-wire technology, this vehicle packaged in a new way, opening up a new world of chassis architectures and customized bodies for individualized expressions.
The car is derived from GM s previous concept of a drive-able fuel cell vehicle called the Autonomy which was debuted at the 2002 North American Motor Show in Detroit. GM does not hope to be selling these cars immediately, due to certain unavoidable hindrances but they are optimistic of seeing these vehicles on the road in the next decade or two.
1. INTRODUCTION
Automobiles as we know today are very complicated machines even though their basic purpose is transportation. The fundamental processes that a car performs are acceleration of wheel speed, their control through braking, the turning of the wheels with the help of the steering mechanism & so on. Given that the overall function of a car is so basic it seems a little strange that almost all cars have the same collection of complex devices crammed under the hood and the same general mass of mechanical and hydraulic linkages running throughout. So considering these facts, automotive engineers for many years, pondered over the question as to why do cars need all these complicated machinery at all. And funnily they found that cars actually don t need all these gizmos and in the future they won t need these.
This seminar deals with such a futuristic vision which the automotive engineers at GM (General Motors) have realized. The HY WIRE concept car the name symbolizes the combination of hydrogen as fuel for the fuel cell propulsion system, and the replacement of conventional mechanical and hydraulic control linkages for steering, braking and other control systems by a drive-by-wire system. "By combining fuel cell and by-wire technology, we've packaged this vehicle in a new way, opening up a new world of chassis architectures and customized bodies for individualized expressions and . It is a significant step towards a new kind of automobile that is substantially more friendly to the environment and provides consumers positive benefits in driving dynamics, safety and freedom of individual expression.
The car is derived from GM s previous concept of a drive-able fuel cell vehicle called the Autonomy which was debuted at the 2002 North American Motor Show in Detroit. GM does not hope to be selling these cars immediately, due to certain unavoidable hindrances but they are optimistic of seeing these vehicles on the road in the next decade or two.
2. CONCEPT OF HY-WIRE CAR
Conventional cars possess other complex machinery in addition to the heart of the car i.e. the IC engine such as carburetor, gearbox, ignition systems, radiator etc. If you've ever looked under the hood of a car, you know an internal combustion engine requires a lot of additional equipment to function correctly. No matter what else they do with a car, designers always have to make room for this equipment. The same goes for mechanical and hydraulic linkages. The basic idea of this system is that the driver maneuvers the various actuators in the car (the wheels, brakes, etc.) more or less directly, by manipulating driving controls connected to those actuators by shafts, gears and hydraulics. In a rack-and-pinion steering system, for example, turning the steering wheel rotates a shaft connected to a pinion gear, which moves a rack gear connected to the car's front wheels. In addition to restricting how the car is built, the linkage concept also dictates how we drive: The steering wheel, pedal and gear-shift system were all designed around the linkage idea.
The defining characteristic of the Hy-wire (and its conceptual predecessor, the AUTOnomy) is that it doesn't have either of these two things. Instead of an engine, it has a fuel cell stack, which powers an electric motor connected to the wheels. Instead of mechanical and hydraulic linkages, it has a drive by wire system -- a computer actually operates the components that move the wheels, activate the brakes and so on, and based on input from an electronic controller. This is the same control system employed in modern fighter jets as well as many commercial planes. The result of these two substitutions is a very different type of car -- and a very different driving experience. There is no steering wheel, there are no pedals and there is no engine compartment. In fact, every piece of equipment that actually moves the car along the road is housed in an 11-inch-thick (28 cm) aluminum chassis -- also known as the skateboard -- at the base of the car. Everything above the chassis is dedicated solely to driver control and passenger comfort.
Skate board chassis
This means the driver and passengers don't have to sit behind a mass of machinery. Instead, the Hy-wire has a huge front windshield, which gives everybody a clear view of the road. The floor of the fiberglass-and-steel passenger compartment can be totally flat, and it's easy to give every seat lots of leg room. Concentrating the bulk of the vehicle in the bottom section of the car also improves safety because it makes the car much less likely to tip over.
But the coolest thing about this design is that it lets you remove the entire passenger compartment and replace it with a different one. If you want to switch from a van to a sports car, you don't need an entirely new car; you just need a new body (which is a lot cheaper).
Before we get to the further features of the car, we will discuss about the 2 most defining technologies that make up the HY WIRE car i.e. the drive by wire system & Hydrogen fuel cell technology.
3. GM HY-WIRE CONCEPT CAR
HISTORY
General Motors, the American automobile behemoth, is essentially the company bringing out the HY WIRE car. But this was not the first alternate fuel powered vehicle that they were bringing out. GM s overarching advanced technology strategy for propulsion systems was designed to build capability for increased power and energy efficiency and reduced emissions with the long-term vision of making the transition to hydrogen-fueled fuel cell powered vehicles that emit only clean water and offer twice the energy efficiency of traditional engines. This technology development focuses on fuel cell power systems, hydrogen production (electrolysis and fuel processing), electric drive control and system integration, hydrogen storage, and affordability.
At the 2002 North American International Motor Show at Detroit, GM unveiled the AUTOnomy car which was the first purpose-designed vehicle combining the benefits of fuel cells and drive by wire technology. Discarding the restrictions of conventional vehicle design based around the internal combustion engine, the vehicle consists of an innovative, skateboard-like chassis, incorporating all the running gear, such as fuel cell powered electric drive, steering and braking systems, onto which a variety of different body styles, from a two-seater sports car to a people carrier, can be placed as required.
The GM Hy-wire incorporates the features first envisioned in the AUTOnomy concept vehicle. All of the touring sedan's propulsion and control systems are contained within an 11-inch-thick skateboard-like chassis, maximizing the interior space for five occupants and their cargo. GM designers and engineers in the United States developed the vehicle chassis and body design, as well as the engineering and electrical system integration. Engineers at GM's research facility in Mainz-Kastel, Germany, integrated the fuel-cell propulsion system, which is the same system used in the HydroGen3 concept, based on an Opel Zafira and shown at the 2001 Frankfurt Motor Show. American designers also worked closely with Italian design house Stile Bertone in Turin, where the body was built. The SKF Group, headquartered in Sweden, developed the by-wire technology in the Netherlands and in Italy.
What led to this name
GM originally dubbed its working concept for a drive-by-wire fuel-cell car the AUTOnomy, to highlight the flexibility of the computer control and switch able car bodies. When it came time to name the actual drivable version, the design team recruited a group of kids, ranging from six to 15 years old, to come up with interesting possibilities. Hy-wire, because it nicely summarized the hydrogen-fuel-cell and drive-by-wire concepts at the vehicle's core.
4. DRIVE BY WIRE
Drive-By-Wire technology is the incorporation of electrical devices to supplant the use of mechanical linkages within a vehicle. This implementation can use electro hydrostatic. Electro pneumatic or electromechanical means. Drive-by-wire systems are forecast to replace many of the traditional hydraulic and mechanical systems in vehicles. Originally known as fly-by-wire because it was used in fighter jets & for other aviation purposes. The past few years has seen its introduction into military vehicles (such as tanks etc.) and heavy vehicles (like Caterpillars). The drive-by-wire system follows closely the fly-by-wire concepts used successfully by the aerospace industry for many years. In conventional control, the movements the driver makes with the steering wheel are transmitted mechanically via the steering column to the steering rack and then to the front wheels. In a by-wire system, the driver s physical movement on the steering wheel is sensed and converted into a digital electronic signal that is transmitted to a smart electro-mechanical actuation unit (SEMAU) that controls the wheels. The same principle can be applied to the braking and gearbox systems.
Like so many of today's technologies, drive-by-wire is primarily a response to tightening emission standards. As with fuel injection and integrated engine controllers, drive-by-wire systems improve engine efficiency while cutting vehicle emissions. They do this by replacing clunky and inaccurate mechanical systems with highly advanced and precise electronic sensors. Currently, drive-by-wire applications are being used to replace the throttle-cable system on newly developed cars like the models already mentioned.
These systems work by replacing conventional throttle-control systems. Instead of relying on a mechanical cable that wind from the back of the accelerator pedal, through the vehicle firewall, and onto the throttle body, drive-by-wire consists of a sophisticated pedal-position
Sensor that closely tracks the position of the accelerator and sends this information to the Engine Control Module (ECM). This is superior to a cable-operated throttle system for the following reasons:
1. By eliminating the mechanical elements and transmitting a vehicle's throttle position electronically.Thedrive-by-wire greatly reduces the number of moving parts in the throttle system. This means greater accuracy, reduced weight, and, theoretically, no service requirements (like oiling and adjusting the throttle cable).
2. The greater accuracy not only improves the driving experience (increased responsiveness and consistent pedal feel regardless of outside temperature or pedal position), but it allows the throttle position to be tied closely into ECM information like fuel pressure, engine temperature and exhaust gas re-circulation. This means improved fuel economy and power delivery as well as lower exhaust emissions.
3. With the pedal inputs reduced to a series of electronic signals, it becomes a simple matter to integrate a vehicle's throttle with non-engine specific items like ABS, gear selection and traction control. This increases the effectiveness of these systems while further reducing the amount of moving parts, service requirements and vehicle weight.
For the driver, the most striking aspects of the interior design of the vehicle are the absence of pedals and steering column. This creates considerably more space inside the car. Drive-by-wire technology eliminates heavy, space-consuming hydraulic and mechanical components, and it has positive environmental implications through the elimination of brake fluids, as well as significant safety benefits.
Electro-mechanical control could allow the steering column and pedals to be removed, a significant potential for improving passive safety for the driver in case of a crash.
In this concept vehicle, the driver s control system combines all the controls that the driver needs in a single unit. Throttle, braking and steering are presented as hand controls. Gear selection is made by a button system that is familiar from the world of motor racing. Lights, windscreen wipers, audio, heating and air conditioning are all located within the driver s immediate reach. The right and left steering control yokes, which are linked, have a travel of +/- 20 degrees. The amount of feel experienced by the driver is fully programmable, as is the relationship between the movement of the yokes and the movement of the front wheels. For the Filo, the steering actuator fits into the original platform s sub-frame assembly.
What does it do to the car
Increases responsiveness of the system, leading to better steering & braking.
Negates the usage of a steering column & reduces the number of moving parts.
It has positive environmental implications through the elimination of brake fluids, as well as significant safety benefits.
Increased capability due to fault monitoring and diagnostics
What does it mean for driver
Enhanced driving experience
Less tiring
Provides more space for passengers upfront due to absence of steering column & associated linkages.
Less or nil maintenance due to near absence of any moving parts
5. FUEL CELL POWER
A fuel cell is an electrochemical energy conversion device that converts hydrogen and oxygen into water, producing electricity and heat in the process. It is very much like a battery that can be recharged while you are drawing power from it. Instead of recharging using electricity, however, a fuel cell uses hydrogen and oxygen. A fuel cell provides a DC (direct current) voltage that can be used to power motors, lights or any number of electrical appliances. There are several different types of fuel cells, each using a different chemistry. Fuel cells are usually classified by the type of electrolyte they use. Some types of fuel cells show promise for use in power generation plants. Others may be useful for small portable applications or for powering cars. The proton exchange membrane fuel cell (PEMFC) is one of the most promising technologies. This is the type of fuel cell that will end up powering cars, buses and maybe even your house. The proton exchange membrane fuel cell (PEMFC) uses one of the simplest reactions of any fuel cell. It is the type of fuel cell used in the Hy-Wire car.
First, let's take a look at what's in a PEM fuel cell. We can see there are four basic elements of a PEMFC:
The anode, the negative post of the fuel cell, has several jobs. It conducts the electrons that are freed from the hydrogen molecules so that they can be used in an external circuit. It has channels etched into it that disperse the hydrogen gas equally over the surface of the catalyst. The cathode, the positive post of the fuel cell, has channels etched into it that distribute the oxygen to the surface of the catalyst. It also conducts the electrons back from the external circuit to the catalyst, where they can recombine with the hydrogen ions and oxygen to form water. The electrolyte is the proton exchange membrane. This specially treated material, which looks something like ordinary kitchen plastic wrap, only conducts positively charged ions. The membrane blocks electrons. The catalyst is a special material that facilitates the reaction of oxygen and hydrogen. It is usually made of platinum powder very thinly coated onto carbon paper or cloth. The catalyst is rough and porous so that the maximum surface area of the platinum can be exposed to the hydrogen or oxygen. The platinum-coated side of the catalyst faces the PEM.
Working:
The pressurized hydrogen gas (H2) enters the fuel cell on the anode side. This gas is forced through the catalyst by the pressure. When an H2 molecule comes in contact with the platinum on the catalyst, it splits into two H+ ions and two electrons (e-). The electrons are conducted through the anode, where they make their way through the external circuit (doing useful work such as turning a motor) and return to the cathode side of the fuel cell.
Meanwhile, on the cathode side of the fuel cell, oxygen gas (O2) is being forced through the catalyst, where it forms two oxygen atoms. Each of these atoms has a strong negative charge. This negative charge attracts the two H+ ions through the membrane, where they combine with an oxygen atom and two of the electrons from the external circuit to form a water molecule (H2O).
This reaction in a single fuel cell produces only about 0.7 volts. To get this voltage up to a reasonable level, many separate fuel cells must be combined to form a fuel-cell stack.
PEMFCs operate at a fairly low temperature (about 176 degrees Fahrenheit, 80 degrees Celsius), which means they warm up quickly and don't require expensive containment structures. Constant improvements in the engineering and materials used in these cells have increased the power density to a level where a device about the size of a small piece of luggage can power a car.
Chemistry of a Fuel Cell
Anode side:
2H2 => 4H+ + 4e-
Cathode side:
O2 + 4H+ + 4e- => 2H2O
Net reaction:
2H2 + O2 => 2H2O
We learned in the last section that a fuel cell uses oxygen and hydrogen to produce electricity. The oxygen required for a fuel cell comes from the air. In fact, in the PEM fuel cell, ordinary air is pumped into the cathode. The hydrogen is not so readily available, however. Hydrogen has some limitations that make it impractical for use in most applications. For instance, you don't have a hydrogen pipeline coming to your house, and you can't pull up to a hydrogen pump at your local gas station.
Hydrogen is difficult to store and distribute, so it would be much more convenient if fuel cells could use fuels that are more readily available. This problem is addressed by a device called a reformer. A reformer turns hydrocarbon or alcohol fuels into hydrogen, which is then fed to the fuel cell. Unfortunately, reformers are not perfect. They generate heat and produce other gases besides hydrogen. They use various devices to try to clean up the hydrogen, but even so, the hydrogen that comes out of them is not pure, and this lowers the efficiency of the fuel cell.
Some of the more promising fuels are natural gas, propane and methanol. Many people have natural-gas lines or propane tanks at their house already, so these fuels are the most likely to be used for home fuel cells. Methanol is a liquid fuel that has similar properties to gasoline. It is just as easy to transport and distribute, so methanol may be a likely candidate to power fuel-cell cars.
Application Of Fuel Cells :
As we've discussed, fuel cells could be used in a number of applications. Each proposed use raises its own issues and challenges.
Automobiles:
Fuel-cell-powered cars will start to replace gas- and diesel-engine cars in about 2005. A fuel-cell car will be very similar to an electric car but with a fuel cell and reformer instead of batteries. Most likely, you will fill your fuel-cell car up with methanol, but some companies are working on gasoline reformers. Other companies hope to do away with the reformer completely by designing advanced storage devices for hydrogen.
Portable Power:
Fuel cells also make sense for portable electronics like laptop computers, cellular phones or even hearing aids. In these applications, the fuel cell will provide much longer life than a battery would, and you should be able to recharge" it quickly with a liquid or gaseous fuel.
Buses:
Fuel-cell-powered buses are already running in several cities. The bus was one of the first applications of the fuel cell because initially, fuel cells needed to be quite large to produce enough power to drive a vehicle. In the first fuel-cell bus, about one-third of the vehicle was filled with fuel cells and fuel-cell equipment. Now the power density has increased to the point that a bus can run on a much smaller fuel cell.
Home Power Generation:
This is a promising application that you may be able to order as soon as 2002. General Electric is going to offer a fuel-cell generator system made by Plug Power. This system will use a natural gas or propane reformer and produce up to seven kilowatts of power (which is enough for most houses). A system like this produces electricity and significant amounts of heat, so it is possible that the system could heat your water and help to heat your house without using any additional energy.
6. FEATURES OF THE HY-WIRE CAR
POWER TRANSMISSION:
The components which comprise the power transmission mechanism are the Hydrogen fuel cell stack & the 3-phase ac motor. We have discussed the working of the fuel cell just before. Now the reaction in a single fuel cell produces only about 0.7 volts. To get this voltage up to a reasonable level, many separate fuel cells must be combined to form a fuel-cell stack. The fuel-cell stack in the Hy-wire is made up of 200 individual cells connected in series, which collectively provide 94 kW (125 bhp) of continuous power and 129 kW (173 bhp) at peak power. This system delivers DC voltage ranging from 125 to 200 volts, depending on the load in the circuit. Three cylindrical storage tanks made by Quantum Fuel Systems Technologies Worldwide, Irvine, CA, rated at 5,000 psi (350 bar) so far provide a range of about 100 km (60 miles), with refueling in five minutes. But judging from earlier comments by GM's vice president of research and development, Larry Burns, higher-pressure tanks of 10,000 psi are
Under consideration. The motor controller boosts this up to 250 to 380 volts and converts it to AC current to drive the three-phase electric motor that rotates the wheels (this is similar to the system used in conventional electric cars).
The electric motor's job is to apply torque to the front wheel axle to spin the two front wheels. The control unit varies the speed of the car by increasing or decreasing the power applied to the motor. When the controller applies maximum power from the fuel-cell stack, the motor's rotor spins at 12,000 revolutions per minute, delivering a torque of 159 pound-feet. A single-stage planetary gear, with a ratio of 8.67:1, steps up the torque to apply a maximum of 1,375 pound-feet to each wheel. That's enough torque to move the 4,200-pound (1,905-kg) car 100 miles per hour (161 kph) on a level road. Smaller electric motors maneuver the wheels to steer the car, and electrically controlled brake calipers bring the car to a stop.
CONTROL:
The Hy-wire's "brain" is a central computer housed in the middle of the chassis. It sends electronic signals to the motor control unit to vary the speed, the steering mechanism to maneuver the car, and the braking system to slow the car down.
At the chassis level, the computer controls all aspects of driving and power use. But it takes its orders from a higher power -- namely, the driver in the car body. The computer connects to the body's electronics through a single universal docking port. This central port works the same basic way as a USB port on a personal computer: It transmits a constant stream of electronic command signals from the car controller to the central computer, as well as feedback signals from the computer to the controller. Additionally, it provides the electric power needed to operate all of the body's onboard electronics. Ten physical linkages lock the body to the chassis structure. The driver's control unit, dubbed the X-drive, is a lot closer to a video game controller than a conventional steering wheel and pedal arrangement. The controller has two ergonomic grips, positioned to the left and right of a small LCD monitor. To steer the car, you glide the grips up and down lightly -- you don't have to keep rotating a wheel to turn, you just have to hold the grip in the turning position. To accelerate, you turn either grip, in the same way you would turn the throttle on a motorcycle; and to brake, you squeeze either grip.
Electronic motion sensors, similar to the ones in high-end computer joysticks, translate this motion into a digital signal the central computer can recognize. Buttons on the controller let you switch easily from neutral to drive to reverse, and a starter button turns the car on. Since absolutely everything is hand-controlled, you can do whatever you want with your feet. The 5.8-inch (14.7-cm) color monitor in the center of the controller displays all the stuff you'd normally find on the dashboard (speed, mileage, fuel level). It also gives you rear-view images from video cameras on the sides and back of the car, in place of conventional mirrors. A second monitor, on a console beside the driver, shows you stereo, climate control and navigation information.
Since it doesn't directly drive any part of the car, the X-drive could really go anywhere in the passenger compartment. In the current Hy-wire sedan model, the X-drive swings around to either of the front two seats, so you can switch drivers without even getting up. It's also easy to adjust the X-drive up or down to improve driver comfort, or to move it out of the way completely when you're not driving.
One of the coolest things about the drive-by-wire system is that you can fine-tune vehicle handling without changing anything in the car's mechanical components -- all it takes to adjust the steering, accelerator or brake sensitivity is some new computer software. In future drive-by-wire vehicles, you will most likely be able to configure the controls exactly to your liking by pressing a few buttons, just like you might adjust the seat position in a car today. It would also be possible in this sort of system to store distinct control preferences for each driver in the family.
Block figure of the Hy Wire Skateboard Chassis
7. TECHNICAL SPECIFICATIONS
Top speed: 100 miles per hour (161 kph)
Weight: 4,185 pounds (1,898 kg)
Chassis length: 14 feet, 3 inches (4.3 meters)
Chassis width: 5 feet, 5.7 inches (1.67 meters)
Chassis thickness: 11 inches (28 cm)
Wheels: eight-spoke, light alloy wheels.
Tires: 20-inch (51-cm) in front and 22-inch (56-cm) in back
Fuel-cell power: 94 kilowatts continuous, 129 kilowatts peak
Fuel-cell-stack voltage: 125 to 200 volts
Motor: 250- to 380-volt three-phase asynchronous electric motor
Crash protection: front and rear "crush zones" (or "crash boxes") to absorb impact energy
Related GM patents in progress: 30
GM team members involved in design: 500+
8. A FEW CONCERNS
The big concern with drive-by-wire vehicles is safety. Since there is no physical connection between the driver and the car's mechanical elements, an electrical failure would mean total loss of control. In order to make this sort of system viable in the real world, drive-by-wire cars will need back-up power supplies and redundant electronic linkages. With adequate safety measures like this, there's no reason why drive-by-wire cars would be any more dangerous than conventional cars. In fact, a lot of
Designers think they'll be much safer, because the central computer will be able to monitor driver input. Another problem is adding adequate crash protection to the car. The other major hurdle for this type of car is figuring out energy-efficient methods for producing, transporting and storing hydrogen for the onboard fuel-cell stacks. With the current state of technology, actually producing the hydrogen fuel can generate about as much pollution as using gasoline engines, and storage and distribution systems still have a long way to go. For that and other reasons, GM is still exploring other storage techniques such as metal hydrides. To make fuel cell cars attractive, they must match current life time expectations of 150,000 miles or more and GM is pretty optimistic about that aspect. Says Larry Burns .other than the flow of electrons and protons, the only moving parts will be the wheels, the suspension and the compressor, so it should have a pretty good life." In terms of production volumes, Burns said some 55 million cars are added each year to the global car park, minus "the old ones that are being retired. By 2010 we estimate the industry will be producing about 70 million a year." And how many of these might be fuel cell vehicles "We see affordable and compelling vehicles as possible by 2010," said Burns. A decade after that he expects "we will move to high penetration, "probably hundreds of thousands of units in the 2020 time frame." Not all stacks will go to transportation because there may be other, stationary applications, but that order of magnitude, says Burns, "makes a lot of sense." Hy-wire is likely to spawn changes in other vehicles, and the first commercial one may not necessarily look like Hy-wire, according to Burns: "we might find fuel cells in conventional vehicles," for example, as well as by-wire technology. Big economies of scales are likely to be derived from the skateboard chassis concept: Today, says Burns, GM has to design and build 12-14 different "platforms" to cover the entire market. But with the skateboard, "there will be fewer platforms" - maybe only two or three. And fuel cell stacks can be "snapped together" - from 10 kW for a house to 1,000 kW for a locomotive.
So will we ever get the chance to buy a Hy-wire General Motors says it fully intends to release a production version of the car in 2010, assuming it can resolve the major fuel and safety issues. But even if the Hy-wire team doesn't meet this goal, GM and other automakers are definitely planning to move beyond the conventional car sometime soon, toward a computerized, environmentally friendly alternative. In all likelihood, life on the highway will see some major changes within the next few decades.
Hy-wire on the road
Hy-Wire s X-Drive
The Interiors of the Hy-wire
9. CONCLUSION
The technology is extremely interesting to people in all walks of life because it offers a means of making power more efficiently and with less pollution. But the coolest thing about this design is that it lets you remove the entire passenger compartment and replace it with a different one. If you want to switch from a van to a sports car, you don't need an entirely new car; you just need a new body (which is a lot cheaper).
The GM concept provides much more value than just zero emissions and twice the fuel economy .It would provide very affordable all-wheel drive, unprecedented safety and comfort, and no oil changes, maintenance worries or trips to the gas station.
10. Bibliography
HowStuffWorks.com
Edmunds.com
Sciam.com
PopSci.com
gm.com
CarDesignNews.com
AutoIntell.com
AutocarIndia.com
BSMotoring.com
TheCarConnection.com
http://evolution.skfgb/
CONTENTS
1. Introduction 1
2. Concept of Hy-wire car 2
3. GM Hy -wire concept car 4
History
4. Drive by wire 5
Working
Applications
5. Fuel cell power 8
6. Features of hy-wire car 13
power transmission
control
7. Technical specifications 16
8. Few concerns 17
9. Conclusion 20
10. Bibliography 21
[attachment=2150]
ABSTRACT
Automobiles as we know today are very complicated machines even though their basic purpose is transportation. The fundamental processes that a car performs are acceleration of wheel speed, their control through braking, the turning of the wheels with the help of the steering mechanism & so on.
The name symbolizes the combination of hydrogen as fuel for the fuel cell propulsion system. The replacement of conventional mechanical and hydraulic control linkages for steering, braking and other control systems by a drive-by-wire system. By combining fuel cell and by-wire technology, this vehicle packaged in a new way, opening up a new world of chassis architectures and customized bodies for individualized expressions.
The car is derived from GM s previous concept of a drive-able fuel cell vehicle called the Autonomy which was debuted at the 2002 North American Motor Show in Detroit. GM does not hope to be selling these cars immediately, due to certain unavoidable hindrances but they are optimistic of seeing these vehicles on the road in the next decade or two.
1. INTRODUCTION
Automobiles as we know today are very complicated machines even though their basic purpose is transportation. The fundamental processes that a car performs are acceleration of wheel speed, their control through braking, the turning of the wheels with the help of the steering mechanism & so on. Given that the overall function of a car is so basic it seems a little strange that almost all cars have the same collection of complex devices crammed under the hood and the same general mass of mechanical and hydraulic linkages running throughout. So considering these facts, automotive engineers for many years, pondered over the question as to why do cars need all these complicated machinery at all. And funnily they found that cars actually don t need all these gizmos and in the future they won t need these.
This seminar deals with such a futuristic vision which the automotive engineers at GM (General Motors) have realized. The HY WIRE concept car the name symbolizes the combination of hydrogen as fuel for the fuel cell propulsion system, and the replacement of conventional mechanical and hydraulic control linkages for steering, braking and other control systems by a drive-by-wire system. "By combining fuel cell and by-wire technology, we've packaged this vehicle in a new way, opening up a new world of chassis architectures and customized bodies for individualized expressions and . It is a significant step towards a new kind of automobile that is substantially more friendly to the environment and provides consumers positive benefits in driving dynamics, safety and freedom of individual expression.
The car is derived from GM s previous concept of a drive-able fuel cell vehicle called the Autonomy which was debuted at the 2002 North American Motor Show in Detroit. GM does not hope to be selling these cars immediately, due to certain unavoidable hindrances but they are optimistic of seeing these vehicles on the road in the next decade or two.
2. CONCEPT OF HY-WIRE CAR
Conventional cars possess other complex machinery in addition to the heart of the car i.e. the IC engine such as carburetor, gearbox, ignition systems, radiator etc. If you've ever looked under the hood of a car, you know an internal combustion engine requires a lot of additional equipment to function correctly. No matter what else they do with a car, designers always have to make room for this equipment. The same goes for mechanical and hydraulic linkages. The basic idea of this system is that the driver maneuvers the various actuators in the car (the wheels, brakes, etc.) more or less directly, by manipulating driving controls connected to those actuators by shafts, gears and hydraulics. In a rack-and-pinion steering system, for example, turning the steering wheel rotates a shaft connected to a pinion gear, which moves a rack gear connected to the car's front wheels. In addition to restricting how the car is built, the linkage concept also dictates how we drive: The steering wheel, pedal and gear-shift system were all designed around the linkage idea.
The defining characteristic of the Hy-wire (and its conceptual predecessor, the AUTOnomy) is that it doesn't have either of these two things. Instead of an engine, it has a fuel cell stack, which powers an electric motor connected to the wheels. Instead of mechanical and hydraulic linkages, it has a drive by wire system -- a computer actually operates the components that move the wheels, activate the brakes and so on, and based on input from an electronic controller. This is the same control system employed in modern fighter jets as well as many commercial planes. The result of these two substitutions is a very different type of car -- and a very different driving experience. There is no steering wheel, there are no pedals and there is no engine compartment. In fact, every piece of equipment that actually moves the car along the road is housed in an 11-inch-thick (28 cm) aluminum chassis -- also known as the skateboard -- at the base of the car. Everything above the chassis is dedicated solely to driver control and passenger comfort.
Skate board chassis
This means the driver and passengers don't have to sit behind a mass of machinery. Instead, the Hy-wire has a huge front windshield, which gives everybody a clear view of the road. The floor of the fiberglass-and-steel passenger compartment can be totally flat, and it's easy to give every seat lots of leg room. Concentrating the bulk of the vehicle in the bottom section of the car also improves safety because it makes the car much less likely to tip over.
But the coolest thing about this design is that it lets you remove the entire passenger compartment and replace it with a different one. If you want to switch from a van to a sports car, you don't need an entirely new car; you just need a new body (which is a lot cheaper).
Before we get to the further features of the car, we will discuss about the 2 most defining technologies that make up the HY WIRE car i.e. the drive by wire system & Hydrogen fuel cell technology.
3. GM HY-WIRE CONCEPT CAR
HISTORY
General Motors, the American automobile behemoth, is essentially the company bringing out the HY WIRE car. But this was not the first alternate fuel powered vehicle that they were bringing out. GM s overarching advanced technology strategy for propulsion systems was designed to build capability for increased power and energy efficiency and reduced emissions with the long-term vision of making the transition to hydrogen-fueled fuel cell powered vehicles that emit only clean water and offer twice the energy efficiency of traditional engines. This technology development focuses on fuel cell power systems, hydrogen production (electrolysis and fuel processing), electric drive control and system integration, hydrogen storage, and affordability.
At the 2002 North American International Motor Show at Detroit, GM unveiled the AUTOnomy car which was the first purpose-designed vehicle combining the benefits of fuel cells and drive by wire technology. Discarding the restrictions of conventional vehicle design based around the internal combustion engine, the vehicle consists of an innovative, skateboard-like chassis, incorporating all the running gear, such as fuel cell powered electric drive, steering and braking systems, onto which a variety of different body styles, from a two-seater sports car to a people carrier, can be placed as required.
The GM Hy-wire incorporates the features first envisioned in the AUTOnomy concept vehicle. All of the touring sedan's propulsion and control systems are contained within an 11-inch-thick skateboard-like chassis, maximizing the interior space for five occupants and their cargo. GM designers and engineers in the United States developed the vehicle chassis and body design, as well as the engineering and electrical system integration. Engineers at GM's research facility in Mainz-Kastel, Germany, integrated the fuel-cell propulsion system, which is the same system used in the HydroGen3 concept, based on an Opel Zafira and shown at the 2001 Frankfurt Motor Show. American designers also worked closely with Italian design house Stile Bertone in Turin, where the body was built. The SKF Group, headquartered in Sweden, developed the by-wire technology in the Netherlands and in Italy.
What led to this name
GM originally dubbed its working concept for a drive-by-wire fuel-cell car the AUTOnomy, to highlight the flexibility of the computer control and switch able car bodies. When it came time to name the actual drivable version, the design team recruited a group of kids, ranging from six to 15 years old, to come up with interesting possibilities. Hy-wire, because it nicely summarized the hydrogen-fuel-cell and drive-by-wire concepts at the vehicle's core.
4. DRIVE BY WIRE
Drive-By-Wire technology is the incorporation of electrical devices to supplant the use of mechanical linkages within a vehicle. This implementation can use electro hydrostatic. Electro pneumatic or electromechanical means. Drive-by-wire systems are forecast to replace many of the traditional hydraulic and mechanical systems in vehicles. Originally known as fly-by-wire because it was used in fighter jets & for other aviation purposes. The past few years has seen its introduction into military vehicles (such as tanks etc.) and heavy vehicles (like Caterpillars). The drive-by-wire system follows closely the fly-by-wire concepts used successfully by the aerospace industry for many years. In conventional control, the movements the driver makes with the steering wheel are transmitted mechanically via the steering column to the steering rack and then to the front wheels. In a by-wire system, the driver s physical movement on the steering wheel is sensed and converted into a digital electronic signal that is transmitted to a smart electro-mechanical actuation unit (SEMAU) that controls the wheels. The same principle can be applied to the braking and gearbox systems.
Like so many of today's technologies, drive-by-wire is primarily a response to tightening emission standards. As with fuel injection and integrated engine controllers, drive-by-wire systems improve engine efficiency while cutting vehicle emissions. They do this by replacing clunky and inaccurate mechanical systems with highly advanced and precise electronic sensors. Currently, drive-by-wire applications are being used to replace the throttle-cable system on newly developed cars like the models already mentioned.
These systems work by replacing conventional throttle-control systems. Instead of relying on a mechanical cable that wind from the back of the accelerator pedal, through the vehicle firewall, and onto the throttle body, drive-by-wire consists of a sophisticated pedal-position
Sensor that closely tracks the position of the accelerator and sends this information to the Engine Control Module (ECM). This is superior to a cable-operated throttle system for the following reasons:
1. By eliminating the mechanical elements and transmitting a vehicle's throttle position electronically.Thedrive-by-wire greatly reduces the number of moving parts in the throttle system. This means greater accuracy, reduced weight, and, theoretically, no service requirements (like oiling and adjusting the throttle cable).
2. The greater accuracy not only improves the driving experience (increased responsiveness and consistent pedal feel regardless of outside temperature or pedal position), but it allows the throttle position to be tied closely into ECM information like fuel pressure, engine temperature and exhaust gas re-circulation. This means improved fuel economy and power delivery as well as lower exhaust emissions.
3. With the pedal inputs reduced to a series of electronic signals, it becomes a simple matter to integrate a vehicle's throttle with non-engine specific items like ABS, gear selection and traction control. This increases the effectiveness of these systems while further reducing the amount of moving parts, service requirements and vehicle weight.
For the driver, the most striking aspects of the interior design of the vehicle are the absence of pedals and steering column. This creates considerably more space inside the car. Drive-by-wire technology eliminates heavy, space-consuming hydraulic and mechanical components, and it has positive environmental implications through the elimination of brake fluids, as well as significant safety benefits.
Electro-mechanical control could allow the steering column and pedals to be removed, a significant potential for improving passive safety for the driver in case of a crash.
In this concept vehicle, the driver s control system combines all the controls that the driver needs in a single unit. Throttle, braking and steering are presented as hand controls. Gear selection is made by a button system that is familiar from the world of motor racing. Lights, windscreen wipers, audio, heating and air conditioning are all located within the driver s immediate reach. The right and left steering control yokes, which are linked, have a travel of +/- 20 degrees. The amount of feel experienced by the driver is fully programmable, as is the relationship between the movement of the yokes and the movement of the front wheels. For the Filo, the steering actuator fits into the original platform s sub-frame assembly.
What does it do to the car
Increases responsiveness of the system, leading to better steering & braking.
Negates the usage of a steering column & reduces the number of moving parts.
It has positive environmental implications through the elimination of brake fluids, as well as significant safety benefits.
Increased capability due to fault monitoring and diagnostics
What does it mean for driver
Enhanced driving experience
Less tiring
Provides more space for passengers upfront due to absence of steering column & associated linkages.
Less or nil maintenance due to near absence of any moving parts
5. FUEL CELL POWER
A fuel cell is an electrochemical energy conversion device that converts hydrogen and oxygen into water, producing electricity and heat in the process. It is very much like a battery that can be recharged while you are drawing power from it. Instead of recharging using electricity, however, a fuel cell uses hydrogen and oxygen. A fuel cell provides a DC (direct current) voltage that can be used to power motors, lights or any number of electrical appliances. There are several different types of fuel cells, each using a different chemistry. Fuel cells are usually classified by the type of electrolyte they use. Some types of fuel cells show promise for use in power generation plants. Others may be useful for small portable applications or for powering cars. The proton exchange membrane fuel cell (PEMFC) is one of the most promising technologies. This is the type of fuel cell that will end up powering cars, buses and maybe even your house. The proton exchange membrane fuel cell (PEMFC) uses one of the simplest reactions of any fuel cell. It is the type of fuel cell used in the Hy-Wire car.
First, let's take a look at what's in a PEM fuel cell. We can see there are four basic elements of a PEMFC:
The anode, the negative post of the fuel cell, has several jobs. It conducts the electrons that are freed from the hydrogen molecules so that they can be used in an external circuit. It has channels etched into it that disperse the hydrogen gas equally over the surface of the catalyst. The cathode, the positive post of the fuel cell, has channels etched into it that distribute the oxygen to the surface of the catalyst. It also conducts the electrons back from the external circuit to the catalyst, where they can recombine with the hydrogen ions and oxygen to form water. The electrolyte is the proton exchange membrane. This specially treated material, which looks something like ordinary kitchen plastic wrap, only conducts positively charged ions. The membrane blocks electrons. The catalyst is a special material that facilitates the reaction of oxygen and hydrogen. It is usually made of platinum powder very thinly coated onto carbon paper or cloth. The catalyst is rough and porous so that the maximum surface area of the platinum can be exposed to the hydrogen or oxygen. The platinum-coated side of the catalyst faces the PEM.
Working:
The pressurized hydrogen gas (H2) enters the fuel cell on the anode side. This gas is forced through the catalyst by the pressure. When an H2 molecule comes in contact with the platinum on the catalyst, it splits into two H+ ions and two electrons (e-). The electrons are conducted through the anode, where they make their way through the external circuit (doing useful work such as turning a motor) and return to the cathode side of the fuel cell.
Meanwhile, on the cathode side of the fuel cell, oxygen gas (O2) is being forced through the catalyst, where it forms two oxygen atoms. Each of these atoms has a strong negative charge. This negative charge attracts the two H+ ions through the membrane, where they combine with an oxygen atom and two of the electrons from the external circuit to form a water molecule (H2O).
This reaction in a single fuel cell produces only about 0.7 volts. To get this voltage up to a reasonable level, many separate fuel cells must be combined to form a fuel-cell stack.
PEMFCs operate at a fairly low temperature (about 176 degrees Fahrenheit, 80 degrees Celsius), which means they warm up quickly and don't require expensive containment structures. Constant improvements in the engineering and materials used in these cells have increased the power density to a level where a device about the size of a small piece of luggage can power a car.
Chemistry of a Fuel Cell
Anode side:
2H2 => 4H+ + 4e-
Cathode side:
O2 + 4H+ + 4e- => 2H2O
Net reaction:
2H2 + O2 => 2H2O
We learned in the last section that a fuel cell uses oxygen and hydrogen to produce electricity. The oxygen required for a fuel cell comes from the air. In fact, in the PEM fuel cell, ordinary air is pumped into the cathode. The hydrogen is not so readily available, however. Hydrogen has some limitations that make it impractical for use in most applications. For instance, you don't have a hydrogen pipeline coming to your house, and you can't pull up to a hydrogen pump at your local gas station.
Hydrogen is difficult to store and distribute, so it would be much more convenient if fuel cells could use fuels that are more readily available. This problem is addressed by a device called a reformer. A reformer turns hydrocarbon or alcohol fuels into hydrogen, which is then fed to the fuel cell. Unfortunately, reformers are not perfect. They generate heat and produce other gases besides hydrogen. They use various devices to try to clean up the hydrogen, but even so, the hydrogen that comes out of them is not pure, and this lowers the efficiency of the fuel cell.
Some of the more promising fuels are natural gas, propane and methanol. Many people have natural-gas lines or propane tanks at their house already, so these fuels are the most likely to be used for home fuel cells. Methanol is a liquid fuel that has similar properties to gasoline. It is just as easy to transport and distribute, so methanol may be a likely candidate to power fuel-cell cars.
Application Of Fuel Cells :
As we've discussed, fuel cells could be used in a number of applications. Each proposed use raises its own issues and challenges.
Automobiles:
Fuel-cell-powered cars will start to replace gas- and diesel-engine cars in about 2005. A fuel-cell car will be very similar to an electric car but with a fuel cell and reformer instead of batteries. Most likely, you will fill your fuel-cell car up with methanol, but some companies are working on gasoline reformers. Other companies hope to do away with the reformer completely by designing advanced storage devices for hydrogen.
Portable Power:
Fuel cells also make sense for portable electronics like laptop computers, cellular phones or even hearing aids. In these applications, the fuel cell will provide much longer life than a battery would, and you should be able to recharge" it quickly with a liquid or gaseous fuel.
Buses:
Fuel-cell-powered buses are already running in several cities. The bus was one of the first applications of the fuel cell because initially, fuel cells needed to be quite large to produce enough power to drive a vehicle. In the first fuel-cell bus, about one-third of the vehicle was filled with fuel cells and fuel-cell equipment. Now the power density has increased to the point that a bus can run on a much smaller fuel cell.
Home Power Generation:
This is a promising application that you may be able to order as soon as 2002. General Electric is going to offer a fuel-cell generator system made by Plug Power. This system will use a natural gas or propane reformer and produce up to seven kilowatts of power (which is enough for most houses). A system like this produces electricity and significant amounts of heat, so it is possible that the system could heat your water and help to heat your house without using any additional energy.
6. FEATURES OF THE HY-WIRE CAR
POWER TRANSMISSION:
The components which comprise the power transmission mechanism are the Hydrogen fuel cell stack & the 3-phase ac motor. We have discussed the working of the fuel cell just before. Now the reaction in a single fuel cell produces only about 0.7 volts. To get this voltage up to a reasonable level, many separate fuel cells must be combined to form a fuel-cell stack. The fuel-cell stack in the Hy-wire is made up of 200 individual cells connected in series, which collectively provide 94 kW (125 bhp) of continuous power and 129 kW (173 bhp) at peak power. This system delivers DC voltage ranging from 125 to 200 volts, depending on the load in the circuit. Three cylindrical storage tanks made by Quantum Fuel Systems Technologies Worldwide, Irvine, CA, rated at 5,000 psi (350 bar) so far provide a range of about 100 km (60 miles), with refueling in five minutes. But judging from earlier comments by GM's vice president of research and development, Larry Burns, higher-pressure tanks of 10,000 psi are
Under consideration. The motor controller boosts this up to 250 to 380 volts and converts it to AC current to drive the three-phase electric motor that rotates the wheels (this is similar to the system used in conventional electric cars).
The electric motor's job is to apply torque to the front wheel axle to spin the two front wheels. The control unit varies the speed of the car by increasing or decreasing the power applied to the motor. When the controller applies maximum power from the fuel-cell stack, the motor's rotor spins at 12,000 revolutions per minute, delivering a torque of 159 pound-feet. A single-stage planetary gear, with a ratio of 8.67:1, steps up the torque to apply a maximum of 1,375 pound-feet to each wheel. That's enough torque to move the 4,200-pound (1,905-kg) car 100 miles per hour (161 kph) on a level road. Smaller electric motors maneuver the wheels to steer the car, and electrically controlled brake calipers bring the car to a stop.
CONTROL:
The Hy-wire's "brain" is a central computer housed in the middle of the chassis. It sends electronic signals to the motor control unit to vary the speed, the steering mechanism to maneuver the car, and the braking system to slow the car down.
At the chassis level, the computer controls all aspects of driving and power use. But it takes its orders from a higher power -- namely, the driver in the car body. The computer connects to the body's electronics through a single universal docking port. This central port works the same basic way as a USB port on a personal computer: It transmits a constant stream of electronic command signals from the car controller to the central computer, as well as feedback signals from the computer to the controller. Additionally, it provides the electric power needed to operate all of the body's onboard electronics. Ten physical linkages lock the body to the chassis structure. The driver's control unit, dubbed the X-drive, is a lot closer to a video game controller than a conventional steering wheel and pedal arrangement. The controller has two ergonomic grips, positioned to the left and right of a small LCD monitor. To steer the car, you glide the grips up and down lightly -- you don't have to keep rotating a wheel to turn, you just have to hold the grip in the turning position. To accelerate, you turn either grip, in the same way you would turn the throttle on a motorcycle; and to brake, you squeeze either grip.
Electronic motion sensors, similar to the ones in high-end computer joysticks, translate this motion into a digital signal the central computer can recognize. Buttons on the controller let you switch easily from neutral to drive to reverse, and a starter button turns the car on. Since absolutely everything is hand-controlled, you can do whatever you want with your feet. The 5.8-inch (14.7-cm) color monitor in the center of the controller displays all the stuff you'd normally find on the dashboard (speed, mileage, fuel level). It also gives you rear-view images from video cameras on the sides and back of the car, in place of conventional mirrors. A second monitor, on a console beside the driver, shows you stereo, climate control and navigation information.
Since it doesn't directly drive any part of the car, the X-drive could really go anywhere in the passenger compartment. In the current Hy-wire sedan model, the X-drive swings around to either of the front two seats, so you can switch drivers without even getting up. It's also easy to adjust the X-drive up or down to improve driver comfort, or to move it out of the way completely when you're not driving.
One of the coolest things about the drive-by-wire system is that you can fine-tune vehicle handling without changing anything in the car's mechanical components -- all it takes to adjust the steering, accelerator or brake sensitivity is some new computer software. In future drive-by-wire vehicles, you will most likely be able to configure the controls exactly to your liking by pressing a few buttons, just like you might adjust the seat position in a car today. It would also be possible in this sort of system to store distinct control preferences for each driver in the family.
Block figure of the Hy Wire Skateboard Chassis
7. TECHNICAL SPECIFICATIONS
Top speed: 100 miles per hour (161 kph)
Weight: 4,185 pounds (1,898 kg)
Chassis length: 14 feet, 3 inches (4.3 meters)
Chassis width: 5 feet, 5.7 inches (1.67 meters)
Chassis thickness: 11 inches (28 cm)
Wheels: eight-spoke, light alloy wheels.
Tires: 20-inch (51-cm) in front and 22-inch (56-cm) in back
Fuel-cell power: 94 kilowatts continuous, 129 kilowatts peak
Fuel-cell-stack voltage: 125 to 200 volts
Motor: 250- to 380-volt three-phase asynchronous electric motor
Crash protection: front and rear "crush zones" (or "crash boxes") to absorb impact energy
Related GM patents in progress: 30
GM team members involved in design: 500+
8. A FEW CONCERNS
The big concern with drive-by-wire vehicles is safety. Since there is no physical connection between the driver and the car's mechanical elements, an electrical failure would mean total loss of control. In order to make this sort of system viable in the real world, drive-by-wire cars will need back-up power supplies and redundant electronic linkages. With adequate safety measures like this, there's no reason why drive-by-wire cars would be any more dangerous than conventional cars. In fact, a lot of
Designers think they'll be much safer, because the central computer will be able to monitor driver input. Another problem is adding adequate crash protection to the car. The other major hurdle for this type of car is figuring out energy-efficient methods for producing, transporting and storing hydrogen for the onboard fuel-cell stacks. With the current state of technology, actually producing the hydrogen fuel can generate about as much pollution as using gasoline engines, and storage and distribution systems still have a long way to go. For that and other reasons, GM is still exploring other storage techniques such as metal hydrides. To make fuel cell cars attractive, they must match current life time expectations of 150,000 miles or more and GM is pretty optimistic about that aspect. Says Larry Burns .other than the flow of electrons and protons, the only moving parts will be the wheels, the suspension and the compressor, so it should have a pretty good life." In terms of production volumes, Burns said some 55 million cars are added each year to the global car park, minus "the old ones that are being retired. By 2010 we estimate the industry will be producing about 70 million a year." And how many of these might be fuel cell vehicles "We see affordable and compelling vehicles as possible by 2010," said Burns. A decade after that he expects "we will move to high penetration, "probably hundreds of thousands of units in the 2020 time frame." Not all stacks will go to transportation because there may be other, stationary applications, but that order of magnitude, says Burns, "makes a lot of sense." Hy-wire is likely to spawn changes in other vehicles, and the first commercial one may not necessarily look like Hy-wire, according to Burns: "we might find fuel cells in conventional vehicles," for example, as well as by-wire technology. Big economies of scales are likely to be derived from the skateboard chassis concept: Today, says Burns, GM has to design and build 12-14 different "platforms" to cover the entire market. But with the skateboard, "there will be fewer platforms" - maybe only two or three. And fuel cell stacks can be "snapped together" - from 10 kW for a house to 1,000 kW for a locomotive.
So will we ever get the chance to buy a Hy-wire General Motors says it fully intends to release a production version of the car in 2010, assuming it can resolve the major fuel and safety issues. But even if the Hy-wire team doesn't meet this goal, GM and other automakers are definitely planning to move beyond the conventional car sometime soon, toward a computerized, environmentally friendly alternative. In all likelihood, life on the highway will see some major changes within the next few decades.
Hy-wire on the road
Hy-Wire s X-Drive
The Interiors of the Hy-wire
9. CONCLUSION
The technology is extremely interesting to people in all walks of life because it offers a means of making power more efficiently and with less pollution. But the coolest thing about this design is that it lets you remove the entire passenger compartment and replace it with a different one. If you want to switch from a van to a sports car, you don't need an entirely new car; you just need a new body (which is a lot cheaper).
The GM concept provides much more value than just zero emissions and twice the fuel economy .It would provide very affordable all-wheel drive, unprecedented safety and comfort, and no oil changes, maintenance worries or trips to the gas station.
10. Bibliography
HowStuffWorks.com
Edmunds.com
Sciam.com
PopSci.com
gm.com
CarDesignNews.com
AutoIntell.com
AutocarIndia.com
BSMotoring.com
TheCarConnection.com
http://evolution.skfgb/
CONTENTS
1. Introduction 1
2. Concept of Hy-wire car 2
3. GM Hy -wire concept car 4
History
4. Drive by wire 5
Working
Applications
5. Fuel cell power 8
6. Features of hy-wire car 13
power transmission
control
7. Technical specifications 16
8. Few concerns 17
9. Conclusion 20
10. Bibliography 21