the hy-wire car report

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					The Hy-Wire Car                                                                        1



                                   Chapter I

                             INTRODUCTION


           Cars are immensely complicated machines, but when you get down

 to it, they do an incredibly simple job. Most of the complex stuff in a car is

 dedicated to turning wheels, which grip the road to pull the car body and

 passengers along. The steering system tilts the wheels side to side to turn the

 car, and brake and acceleration systems control the speed of the wheels.



           Given that the overall function of a car is so basic (it just needs to

 provide rotary motion to wheels), 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.

 Why do cars necessarily need a steering column, brake and acceleration pedals,

 a combustion engine, a catalytic converter and the rest of it?



           According to many leading automotive engineers, they don't; and

 more to the point, in the near future, they won't. Most likely, a lot of us will be

 driving radically different cars within 20 years. And the difference won't just

 be under the hood -- owning and driving cars will change significantly, too.




Dept. of Mechanical Engg.                                         MESCE Kuttippuram
The Hy-Wire Car                                                                   2



           In this article, we'll look at one interesting vision of the future,

 General Motor's remarkable concept car, the Hy-wire. GM may never actually

 sell the Hy-wire to the public, but it is certainly a good illustration of various

 ways cars might evolve in the near future.




                            GM's sedan model Hy-wire




Dept. of Mechanical Engg.                                        MESCE Kuttippuram
The Hy-Wire Car                                                                       3


                                  Chapter- II

                            HY-WIRE BASICS



           Two basic elements largely dictate car design today: the internal

 combustion engine and mechanical and hydraulic linkages. 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


Dept. of Mechanical Engg.                                        MESCE Kuttippuram
The Hy-Wire Car                                                                     4

 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, 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.



          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).

Dept. of Mechanical Engg.                                       MESCE Kuttippuram
The Hy-Wire Car                                                                 5




  The Hy-wire has wheels, seats and windows like a conventional car, but the
  similarity pretty much ends there. There is no engine under the hood and no
                        steering wheel or pedals inside.




Dept. of Mechanical Engg.                                    MESCE Kuttippuram
The Hy-Wire Car                                                                     6



                                 Chapter III

                                   POWER


          The "Hy" in Hy-wire stands for hydrogen, the standard fuel for a fuel

 cell system. Like batteries, fuel cells have a negatively charged terminal and a

 positively charged terminal that propel electrical charge through a circuit

 connected to each end. They are also similar to batteries in that they generate

 electricity from a chemical reaction. But unlike a battery, you can continually

 recharge a fuel cell by adding chemical fuel -- in this case, hydrogen from an

 onboard storage tank and oxygen from the atmosphere.



          The basic idea is to use a catalyst to split a hydrogen molecule (H2)

 into two H protons (H+, positively charged single hydrogen atoms) and two

 electrons (e-). Oxygen on the cathode (positively charged) side of the fuel cell

 draws H+ ions from the anode side through a proton exchange membrane, but

 blocks the flow of electrons. The electrons (which have a negative charge) are

 attracted to the protons (which have a positive charge) on the other side of the

 membrane, but they have to move through the electrical circuit to get there.

 The moving electrons make up the electrical current that powers the various

 loads in the circuit, such as motors and the computer system. On the cathode

 side of the cell, the hydrogen, oxygen and free electrons combine to form water

 (H2O), the system's only emission product.




Dept. of Mechanical Engg.                                      MESCE Kuttippuram
The Hy-Wire Car                                                             7




       In a hydrogen fuel cell, a catalyst breaks hydrogen molecules in the
 anode into protons and electrons. The protons move through the exchange
 membrane, toward the oxygen on the cathode side, and the electrons make
 their way through a wire between the anode and cathode. On the cathode side,
 the hydrogen and oxygen combine to form water. Many cells are connected in
 series to move substantial charge through a circuit.



Dept. of Mechanical Engg.                                   MESCE Kuttippuram
The Hy-Wire Car                                                                   8



      In a hydrogen fuel cell, a catalyst breaks hydrogen molecules in the

 anode into protons and electrons. The protons move through the exchange

 membrane, toward the oxygen on the cathode side, and the electrons make

 their way through a wire between the anode and cathode. On the cathode side,

 the hydrogen and oxygen combine to form water. Many cells are connected in

 series to move substantial charge through a circuit.



      One fuel cell only puts out a little bit of power, so you need to combine

 many cells into a stack to get much use out of the process. The fuel-cell stack

 in the Hy-wire is made up of 200 individual cells connected in series, which

 collectively provide 94 kilowatts of continuous power and 129 kilowatts at

 peak power. The compact cell stack (it's about the size of a PC tower) is kept

 cool by a conventional radiator system that's powered by the fuel cells

 themselves.




               The hydrogen tanks and fuel-cell stack in the Hy-wire




Dept. of Mechanical Engg.                                      MESCE Kuttippuram
The Hy-Wire Car                                                                      9

           This system delivers DC voltage ranging from 125 to 200 volts,

 depending on the load in the circuit. 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.



           The gaseous hydrogen fuel needed to power this system is stored in

 three cylindrical tanks, weighing about 165 pounds (75 kilograms) total. The

 tanks are made of a special carbon composite material with the high structural

 strength needed to contain high-pressure hydrogen gas. The tanks in the current

 model hold about 4.5 pounds (2 kg) of hydrogen at about 5,000 pounds per

 square inch (350 bars). In future models, the Hy-wire engineers hope to

 increase the pressure threshold to 10,000 pounds per square inch (700 bars),

 which would boost the car's fuel capacity to extend the driving range.

Dept. of Mechanical Engg.                                       MESCE Kuttippuram
The Hy-Wire Car                                                              10



          Ultimately, GM hopes to get the fuel-cell stack, motors and

 hydrogen-storage tanks small enough that they can reduce the chassis thickness

 from 11 inches to 6 inches (15 cm). This more compact "skateboard" would

 allow for even more flexibility in the body design.




Dept. of Mechanical Engg.                                    MESCE Kuttippuram
The Hy-Wire Car                                                               11



                                  Chapter IV

                                 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.




Dept. of Mechanical Engg.                                     MESCE Kuttippuram
The Hy-Wire Car                                                        12




                    GM's diagram of the Autonomy design




Dept. of Mechanical Engg.                                 MESCE Kuttippuram
The Hy-Wire Car                                                                    13



      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 (imagine

 sticking them in a massager during the drive to and from work every day).




Dept. of Mechanical Engg.                                       MESCE Kuttippuram
The Hy-Wire Car                                                                   14




                              The Hy-wire's X-drive




                  The X-drive can slide to either side of the vehicle.




Dept. of Mechanical Engg.                                            MESCE Kuttippuram
The Hy-Wire Car                                                                 15



           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.




Dept. of Mechanical Engg.                                       MESCE Kuttippuram
The Hy-Wire Car                                                         16




                                                                    .



      GM concept of the Autonomy with and without a body attached




Dept. of Mechanical Engg.                             MESCE Kuttippuram
The Hy-Wire Car                                                                  17



           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 (see How the Hydrogen Economy Works for more information).



           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.

Dept. of Mechanical Engg.                                        MESCE Kuttippuram
The Hy-Wire Car                                                            18



                                 Chapter -V

                  HY-WIRE CAR SPECIFICATION


        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+




Dept. of Mechanical Engg.                                   MESCE Kuttippuram
The Hy-Wire Car                                                               19



                              CONCLUSION


      By using Hy-Wire technology certain multi national companies like

 General Motors is fully intended to release a production version of the car in

 2010, assuming it can resolve the major fuel and safety issues. The life on the

 high way will see some major changes within the next few decades.




Dept. of Mechanical Engg.                                     MESCE Kuttippuram
The Hy-Wire Car                                       20



                            REFERENCES



      www.howstuffworks.com
      www.generalmoters.com




Dept. of Mechanical Engg.                MESCE Kuttippuram
The Hy-Wire Car                                                                 21



                       ACKNOWLEDGEMENT

      First of all I thank the almighty for providing me with the strength and
 courage to present the seminar.


      I avail this opportunity to express my sincere gratitude towards
 Dr. T.N. Sathyanesan, head of         mechanical engineering department, for
 permitting me to conduct the seminar. I also at the outset thank and express my
 profound gratitude to my seminar guide Mr. Sasikumar and staff incharge
 Asst. Prof. Mrs. Jumailath Beevi. D., for their inspiring assistance,
 encouragement and useful guidance.


      I am also indebted to all the teaching and non- teaching staff of the
 department of mechanical engineering for their cooperation and suggestions,
 which is the spirit behind this report. Last but not the least, I wish to express
 my sincere thanks to all my friends for their goodwill and constructive ideas.




                                                        RIJIL K.P.




Dept. of Mechanical Engg.                                       MESCE Kuttippuram
The Hy-Wire Car                                                                  22



                                 ABSTRACT


          Hy-Wire Car is without mechanical and hydraulic linkage end engine.

 Instead of these it contain a fuel cell stack and a drive by wire system. It is

 fully automated car it is a future car. In future it will have a wide application.

 The problem with fuel consumption and pollution can be minimize to certain

 level.




Dept. of Mechanical Engg.                                        MESCE Kuttippuram
The Hy-Wire Car                                     23



                            CONTENTS



   1. INTRODUCTION                          1

   2. HY-WIRE BASICS                        3

   3. POWER                                 6

   4. CONTROL                               11

   5. HY-WIRE CAR SPECIFICATION             18

   6. CONCLUSION                            19

   7. REFERENCES                            20




Dept. of Mechanical Engg.              MESCE Kuttippuram

				
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