Have you ever imagined to see the Nations most ultimate Automotive Ingenious Minds competing against each other in a single Arena!? Ever Imagined the Momentum of their Racing!? The magnitude of their true Potential!? Their Conflict to Conquer the Ultimate Peak of Success?! Well! Why are you imagining it. See, feel & go crazy!
The Department of Automobile Engineering, Madras Institute of Technology, is all set to Rev up your brains from the Neutral with its most prestigious Techno-Management Fest “AUTOMEET 10″. Buckle up your seat belts! The race falls on March 15th. Be there!
Paper Presentation
The classic symposium special. A platform for presenting ideas that can potentially revolutionise our lives. Small or big, it doesn’t matter. What matters is the benefits that we can realise from it. So come forward to put your thoughts into action. Show us how you can change the world, one slide at a time.
Projectum
Imported C&B Show
Lose yourself in the world of Imported Metal
Auto Q
You know, tough brain-racking questions of cars & bikes you’ve never heard/seen before. And some easy ones that can still cause you to bang your head. Either way, it packs a turbo-charged punch!
Gen Q
The best place to exhibit your knowledge about Tintin’s hobbies and Genghis khan’s palace
Why?
My car hates vanilla ice cream. You know why? It doesn’t have an antipercolator, can that be a reason? Why does a spoonful of sugar in this fuel tank prevent a car from starting? If u think u can answer these questions. You know where to head up to.
RC Car Race
Lets give your brains a break. Let your fingers do the racing.
Non – IC RC Car Race
Drag Race
Air Car
Ever thought of doing something useful with your emptied coke bottle other than throwing it to the bin?! Well! We have got the place which you have been looking for! Think Innovative! Showcase your talents.
Virtual Remodelling
Don’t have the dough to buy and remodel a new car? Why not do it in a computer. After all, that pretty much what we all have been doing in NFS, right? Show us how good you are at transforming a lemon into a limousine. With the help of some virtual car ‘editing’ softwares , of course.
Cad Modelling
Precision engineering begins here. Wield the powers of CATIA and PRO-E to give shape to your thoughts. Show us that design and analysis that can be done without breaking into a sweat.
Car Sketching
Some people tend to ask: What’s so great about sketching? Even small kids draw cars from their flights of fantasy. Does that quality? Actually it does. There is no car in the world which originated without a simple sketch. Such is the importance of car sketching that Giorgetto Giugiaro, of all people, swear by it, so you know that you’re up to. Sketch a car that you think will make people fall head over heels just looking at it. Aesthetics takes the front seat here, and if stuff like aerodynamics and ergonomics have a role to play, you can get some brownie points!
Contraption
Tech Xword
Tougher than the Guardian. More challenging than the Hindu. Are we selling newspapers? No, is just our auto crossword. So big that you’ll need a couple of hours to solve it. And given just one hour to do so. What’s life without a challenge, you say?
PC Gaming
The ultimate test of your communication, determination, accuracy and presence of mind. The CS Mini-Tourney at Automeet will be a tactical warzone for the meanest clans in Chennai. Everyone is invited to show their proness. Prove that you can mag, drag and pull a headie with ease. Be there or Be square.
For Further Details: www.automeet10.com
The Bugatti Veyron EB 16.4 is the most recent version of a mid-engined full-sized grand tourer developed by the German car-manufacturer Volkswagen and produced by the Volkswagen-brand Bugatti Automobiles SAS at their headquarters in Château St. Jean in Molsheim (Alsace, France), and whose production and development is often credited to Ferdinand Karl Piech. It is named after French racing driver Pierre Veyron, who won the 24 hours of Le Mans in 1939 while racing for the original Bugatti company. It was named “Car Of The Decade” by the BBC television programme Top Gear.
Two hundred and twenty Veyrons are known to have been built and delivered since production began in 2005 and ended in late 2008. Special variants of the Veyron include the Pur Sang, the Fbg Par Hermes, the Sang Noir, the Targa, the Vincero, and the Bleu Centenaire. It will be replaced with the Grand Sport, which is essentially a Veyron convertible.
The Veyron features an 8.0 litre W16 engine — sixteen cylinders in two banks of eight cylinders, or the equivalent of two narrow angle V8 engines mated in a “W” configuration. Each cylinder has four valves for a total of sixty four, but the narrow staggered eight configuration allows two overhead camshafts to drive two banks of cylinders so only four camshafts are needed. The engine is fed by four turbochargers and displaces 7,993 cubic centimetres (487.8 cu in), with a square 86 mm by 86 mm (3.4 in × 3.4 in) bore and stroke.
The transmission is a dual clutch Direct-Shift Gearbox computer-controlled automatic with seven gear ratios, with magnesium paddles behind the steering wheel and a shift time of less than 150 milliseconds. This is designed and manufactured by Ricardo of England (and not Borg-Warner who designed the six speed DSG used in the mainstream marques of the Volkswagen Group). The Veyron can be driven in either semi automatic or fully automatic mode. A replacement transmission for the Veyron costs just over $120,000. It also features fulltime permanent four wheel drive, using the Haldex Traction system. It uses special Michelin PAX run flat tyres, designed specifically for the Veyron to accommodate its top speed, which reportedly cost $25,000 US per set. The tyres can only be removed from the rims in France, a service which reportedly costs $70,000. Kerb weight is 2,034.8 kilograms (4,486 lb). This gives the car a power to weight ratio, according to Volkswagen Group’s 736 kilowatts (1,001 PS; 987 bhp) figures, of 446.3 bhp per ton.
The car’s wheelbase is 2,710 mm (106.7 in). Overall length is 4,462 mm (175.7 in), width 1,998 mm (78.7 in) and height 1,204 mm (47.4 in).
The Bugatti Veyron has a total of ten radiators.
It has a drag coefficient of 0.41 (normal condition) and 0.36 (after lowering to the ground), and a frontal area of 2.07 square metres (22.3 sq ft). This gives it a CdA ft² value of 8.02.
According to Volkswagen Group, the DIN rated motive power output, approved by TÜV Süddeutschland, of the final production Veyron engine produces 1,001 metric horsepower (736 kW; 987 bhp) and generates 1,250 newton metres (922 ft·lbf) of torque. The figure has been confirmed by Bugatti officials to actually be conservative, with the real total being 1020 bhp or more.
The top speed was verified by James May on Top Gear for the November 2006 issue, again at Volkswagen Group’s private Ehra-Lessien test track, where the final-production car hit 407.9 km/h (253.5 mph), which equated to almost one-third of the speed of sound at sea level. As the Bugatti Veyron approached the top speed during the test, May said that “the tyres will only last for about fifteen minutes, but it’s okay because the fuel runs out in twelve minutes”. He also gave an indication of the power requirements: at a constant 155 mph, the Veyron is using approximately 270 metric horsepower (200 kW; 270 bhp); the next 100 mph requires an additional 730 metric horsepower (540 kW; 720 bhp). Jeremy Clarkson, driving a Veyron from Italy to London, noted that at top speed, the engine consumes 10,000 imperial gallons (45,000 L) of air per minute (as much as a human breathes in four days). With a 0 to 60 time of 2.4 seconds, the Veyron was the fastest legal street car between the years 2005 and 2007. Once back in the Top Gear studio, May was asked by co-presenter Jeremy Clarkson what the Veyron felt like to drive at 407 km/h (253 mph), May replied that it was “totally undramatic”, and very stable at speed.
German inspection officials recorded an average top speed of 408.47 km/h (253.81 mph)[19] during test sessions on the Ehra-Lessien test track on 19 April 2005. The Bugatti website still refers to the Veyron as the fastest production vehicle of all time even though this title has since been taken by the SSC Ultimate Aero TT.
The car’s everyday top speed is listed at 350 km/h (220 mph). When the car reaches 220 km/h (140 mph), hydraulics lower the car until it has a ground clearance of about 9 cm (3.5 in.). At the same time, the wing and spoiler deploy. This is the “handling mode”, in which the wing helps provide 3,425 newtons (770 lbf) of downforce, holding the car to the road, and helping the Bugatti Veyron perform 1.34 g forces on a 300 foot skidpad.[13] The driver must, using a special key (the “Top Speed Key”), toggle the lock to the left of his seat in order to attain the maximum (average) speed of 407 km/h (253 mph). The key functions only when the vehicle is at a stop, when a checklist then establishes whether the car and its driver are ready to enable ‘top speed’ mode. If all systems are go, the rear spoiler retracts, the front air diffusers shut and the ground clearance, normally 12.5 cm (4.9 in), drops to 6.5 cm (2.6 in).
The Veyron’s brakes use cross drilled, radially vented carbon fibre reinforced silicon carbide (C/SiC) composite discs, manufactured by SGL Carbon, which have a much greater resistance to brake fade when compared with conventional cast iron discs. The lightweight aluminium alloy monobloc brake calipers are made by AP Racing; the fronts have eight titanium pistons and the rear calipers have six pistons. Bugatti claims maximum deceleration of 1.3 G on road tyres. As an added safety feature, in the event of brake failure, an anti-lock braking system (ABS) has also been installed on the handbrake.
Prototypes have been subjected to repeated 1.0 G braking from 312 km/h (194 mph) to 80 km/h (50 mph) without fade. With the car’s acceleration from 80 km/h (50 mph) to 312 km/h (194 mph), that test can be performed every 22 seconds. At speeds above 200 km/h (120 mph), the rear wing also acts as an airbrake, snapping to a 55-degree angle in 0.4 seconds once brakes are applied, providing an additional 0.68 G (4.9 m/s²) of deceleration (equivalent to the stopping power of an ordinary hatchback). Bugatti claims the Veyron will brake from 400 km/h (250 mph) to a standstill in less than 10 seconds.
The Bugatti Veyron is a car built around an engine. Essentially, Bugatti made the decision to blow the doors off the supercar world by creating a 1,000-horsepower engine. Everything else follows from that resolution.
So let’s start with the engine. How would you begin the design process for an engine this powerful? If you have know how a car engines works, you know that if you want to create a 1,000-horsepower engine, it has to be able to burn enough gasoline to generate 1,000 horsepower. That works out to about 1.33 gallons (5 liters) of gasoline per minute.
We need a 16-liter engine to burn 1.33 gallons of gas per minute. That actually makes sense — the engine in the Dodge Viper is 8.0 liters in displacement and produces 500 hp.
But there’s a problem: A 16-liter V-8 engine would be very large. And the pistons would be massive, so there would be no way it could turn at 6,000 rotations per minute (rpm). It might turn at a maximum of 2,000 rpm, meaning that you would need an immense 48-liter engine to generate 1,000 hp. Clearly an engine that big is impossible in a passenger car.
So how did Bugatti fit 1,000 horsepower into a passenger car?
Bugatti did two things to create a compact engine capable of producing 1,000 hp.
The first and most obvious thing is turbocharging.
The Bugatti Veyron’s 16-cylinder monster engine produces 1,001 horsepower for a top speed of more than 250 mph. And it’s a passenger car. Check out the Bugatti. Amazing isn`t it? If you have know how a turbocharger works, you know that one easy way to make an engine more powerful without making the engine bigger is to stuff more air into the cylinders on each intake stroke. Turbochargers do that. A turbo pressurizes the air coming into the cylinder so the cylinder can hold more air. If you stuff twice as much air in each cylinder, you can burn twice as much gasoline. In reality, it’s not quite a perfect ratio like that, but you get the idea. The Bugatti uses a maximum turbo boost of 18 PSI to double the output power of its engine. Therefore, turbocharging allows Bugatti to cut the size of the engine from 16 liters back down to a more manageable 8 liters. To generate that much air pressure, the Bugatti requires four separate turbochargers arranged around the engine.
The second thing Bugatti engineers did, both to keep the RPM redline high and to lower lag time when you press the accelerator, was to double the number of cylinders.
The Bugatti has a very rare 16-cylinder engine.
There are two easy ways to create a 16-cylinder engine.
The latter technique is, in fact, the way Bugatti created its first 16-cylinder cars in the early 20th century.For the Veyron, Bugatti chose a much more challenging path. Essentially, Bugatti merged two V-8 engines onto one another, and then let both of them share the same crankshaft. This configuration creates the W-16 engine found in the Veyron. The two V’s create a W.
The special features of the Bugatti W-16 engine are amazing. For example:
Everything about the engine is superlative.And it is remarkably compact. It measures just 710 mm (27 inches) long, 889 mm (35 inches) wide and 730 mm (28.7 inches) high. This is the beauty of Bugatti’s W-16 approach — the engineers managed to fit 1,000 hp into a reasonably sized package.
Transmission
The transmission is unique, in particular because it has to harness about twice as much torque as any previous sports-car transmission. It has:
This computer-controlled system is identical to the sort of system found in a Formula 1 car or a Champ car. There is no clutch pedal or shift lever for the driver to operate — the computer controls the clutch disks as well as the actual shifting. The computer is able to shift gears in 0.2 seconds. It would be almost impossible for all of the torque available from the W-16 engine to flow out to just two wheels without constant wheel-spin. Therefore, the Veyron has full-time all-wheel drive. By applying the engine’s power to all four wheels through a computer-controlled traction-control system, the car is able to harness all of the engine’s horsepower, even at full acceleration.
Body Design
According to one of the Veyron’s designers, the biggest challenge in creating the Veyron was the aerodynamics.
How do you keep a 250-mph passenger car on the road?
An F-1 car or a Champ car can travel at 250 mph or more, but they have a uniquely designed body, a single driver lying in a reclining position, just an inch or so of ground clearance and an aero-package made up of large wings to generate massive downforce. The Bugatti, on the other hand, is trying to look like a normal car and seat two passengers. The Veyron’s dimensions help to some extent. The car is 79 inches (200 cm) wide, 176 inches (447 cm) long and only 48 inches (122 cm) high. Keep in mind that a Hummer 2 is 81.2 inches wide. The Bugatti is extremely wide for its height. The underside of the Veyron, like an F-1 car, is streamlined and venturi-shaped to increase downforce. There is also a wing in the back of the Veyron (see below) that extends automatically at high speed to increase downforce and keep the car glued to the road. According to Popular Science: Hypercar, “With the moving tail spoiler we’ve got enough downforce now, about 100 kg (221 pounds) at the rear and 80 kg (177 pounds) at the front at top speed.”
The Veyron uses two snorkel-like devices one on either side of the engine to manage airflow. The Veyron has three reasons for managing airflow:
The engine of the Veryon sits behind the driver, so roof-mounted snorkels, the rear-deck vents and side-mounted scoops bring air to the engine and rear brakes.
The size of the engine and transmission, along with the four-wheel-drive system and the four drive shafts, along with the opulence of the passenger compartment (discussed in the next section) and the car’s oversized dimensions, all add weight. Even though the body is sculpted in carbon fiber to minimize its mass, the car weighs in at about 4,300 pounds (1,950 kg). For comparison, a Dodge Viper weighs about 1,000 pounds (454 kg) less.
Even the tires for the Veyron are unique. They’re specially designed by Michelin to handle the stress of driving at 250 mph. The tires need to be sticky like a race car’s and able to handle 1.3 G’s on the skidpad. However, they also need to last longer than the 70 or so miles of a typical race tire.
Michelin therefore created completely new tires to handle the Veyron’s unique requirements. In the rear, the tires are 14.4 inches (36.6 cm) wide. Specifically, the tires measure 245/690 R 520 A front and 365/710 R 540 A rear, where 245 and 365 are the width in millimeters (9.5 and 14.4 inches respectively). The rims are 520 mm and 540 mm in diameter (approximately 20 inches). These tires, in other words, are massive — the rears are the widest ever produced for a passenger car.
The tires use the Michelin PAX system. Their pressure is monitored automatically, and they can run flat for approximately 125 miles (201 km) at 50 mph (80 kph). According to Michelin, the run-flat detection system “plays an integral role in active safety in PAX System. Its role is to inform you of a loss of pressure, either gradual or sudden.” Once warned of an air leak by the PAX system, you can reduce your speed and head toward a tire repair center.
One advantage of the PAX system and its run-flat ability is that it eliminates the need for a spare tire.
The Interior The Veyron seats two in lavish style. The interior is swathed almost completely in leather — the dash, seats, floor and sides are all leather. Only the instruments and a few metal trim pieces interrupt the leather experience.
The car also surrounds its occupants with every sort of electronic nicety, including a remarkable stereo system, navigation system, etc.
Is all of this worth a million bucks? Who knows. But regardless, the Veyron represents a remarkable technological achievement.
The Veyron is also likely to represent the far end of the automotive performance spectrum for some time to come. To create a car much faster will require adding even more weight, and delivering even more power to the wheels. The added weight means diminishing returns in the power-to-weight domain. Additional power means more wheelspin.
Look at a Champ car and consider how radical its appearance is compared to a passenger car. Consider also that a Champ car does not go much faster than the Veyron. The Veyron probably approaches the outer limits of the passenger car envelope, and we are unlikely to see much beyond the Veyron in terms of performance.
This is, in other words, as good as it gets.
Well, here is a video of how fast the Veyron can actually fly.
References: http://en.wikipedia.org/wiki/Bugatti_Veyron
http://auto.howstuffworks.com/bugatti.htm
VTEC, Variable Valve Timing and Lift Electronic Control is a valve train system developed by Honda to improve the volumetric efficiency of a four-stroke internal combustion engine. This system uses two camshaft profiles and electronically selects between the profiles. It was invented by Honda R&D engineer Ikuo Kajitani. It can be said that VTEC, the original Honda variable valve control system, originated from REV (Revolution-modulated valve control) introduced on the CBR400 in 1983 known as HYPER VT EC. VTEC was the first system of its kind, though other variable valve timing and lift control systems have been produced by other manufacturers (MIVEC from Mitsubishi, VVTL-i from Toyota, VarioCam Plus from Porsche, VVL from Nissan, etc).
i-VTEC
(intelligent-VTEC) introduced continuously variable camshaft phasing on the intake cam of DOHC VTEC engines. The technology first appeared on Honda’s K-series four cylinder engine family in 2001 (2002 in the U.S.). In the United States, Honda first debuted the technology on the 2003 Honda Civic Si EP3 with the economy version.
Valve lift and duration are still limited to distinct low- and high-RPM profiles, but the intake camshaft is now capable of advancing between 25 and 50 degrees (depending upon engine configuration) during operation. Phase changes are implemented by a computer controlled, oil driven adjustable cam gear. Phasing is determined by a combination of engine load and rpm, ranging from fully retarded at idle to somewhat advanced at full throttle and low rpm. The effect is further optimization of torque output, especially at low and midrange RPM.
The K-Series motors have two different types of i-VTEC systems implemented. The first is for the performance motors like in the RSX Type S or the TSX and the other is for economy motors found in the CR-V or Accord. The performance i-VTEC system is basically the same as the DOHC VTEC system of the B16A’s; both intake and exhaust have 3 cam lobes per cylinder. However the valvetrain has the added benefit of roller rockers and continuously variable intake cam timing. Performance i-VTEC is a combination of conventional DOHC VTEC with VTC.
The economy i-VTEC is more like the SOHC VTEC-E in that the intake cam has only two lobes, one very small and one larger, as well as no VTEC on the exhaust cam. The two types of motor are easily distinguishable by the factory rated power output: the performance motors make around 200 hp (150 kW) or more in stock form and the economy motors do not make much more than 160 hp (120 kW) from the factory.
The new SOHC i-VTEC implementation is an entirely new implementation that was introduced on the 2006 Honda Civic’s R-series four cylinder SOHC engines. This implementation uses the so-called “fuel economy cam” and “high output cam” on one of the two intake valves of each cylinder (another intake valve is fixed). The “fuel economy cams” are designed to retard the closure of one intake valve and are activated between 1000-3500RPM and under low load condition. When “fuel economy cams” are activated, the intake valve closes well after the piston has started moving upwards in the compression stroke. During this time, the drive-by-wire throttle valve is open wider than normal. Due to the delayed closing of intake valve, a part of the intake mixture that has entered the combustion chamber is forced out again into the intake manifold. That way, the engine “emulates” a lower displacement than its actual one (its operation is also similar to an Atkinson cycle engine, with uneven compression and combustion strokes), which reduces pumping losses thus reducing fuel consumption and increases its efficiency. VTEC-off on the R18A means it can be considered to be running “high output cams”. When the right conditions are achieved for fuel economy, VTEC engages the 2nd set, the ‘low’ or ‘economy’ cams. Thus VTEC-on on the R18A means it is running low cams.
According to Honda, this measure alone can reduce pumping losses by 16%. Under heavier loads, the engine switches back into its “high output cams”, and it operates like a regular 4 stroke Otto cycle engine. This implementation of i-VTEC was initially introduced in the R18A1 engine found under the bonnet of the 8th generation Civic, with a displacement of 1.8 L and an output of 140 PS (100 kW; 140 hp). Recently, another variant was released, the 2.0 L R20A2 with an output of 150 PS (110 kW; 150 hp), which powers the EUDM version of the all-new CRV. SOHC i-VTEC
With the continued introduction of vastly different i-VTEC systems, one may assume that the term is now a catch-all for creative valve control technologies from Honda.
In 2003, Honda introduced an i-VTEC V6 (an update of the J-series) that includes Honda’s cylinder deactivation technology which closes the valves on one bank of (3) cylinders during light load and low speed (below 80 km/h (50 mph)) operation. The technology was originally introduced to the US on the Honda Odyssey minivan, and can now be found on the Honda Accord Hybrid, the 2006 Honda Pilot, and the 2008 Honda Accord.
i-VTEC VCM was also used in 1.3L 4-cylinder engines used in Honda Civic Hybrid.
It is a version of i-VTEC with direct injection.
It was first used in 2003 Honda Stream.
This is how an ivtec engine works
And this is the Honda Hybrid System
Reference: www.wikipedia.org
www.world.honda.com
Power steering is a system for reducing the steering effort on cars by using an external power source to assist in turning the wheels. Power steering was invented in the 1920s by Francis W. Davis and George Jessup in Waltham, Massachusetts. Chrysler Corporation introduced the first commercially available power steering system on the 1951 Chrysler Imperial under the name Hydraguide. Most new vehicles now have power steering, although in the 1970s and 1980s it was the exception rather than the rule, at least on European cars. The trend to front wheel drive, greater vehicle mass and wider tires means that modern vehicles would be extremely difficult to manoeuvre at low speeds (e.g. when parking) without assistance.
Most power steering systems work by using a belt driven pump to provide hydraulic pressure to the system. This hydraulic pressure is generated by a rotary-vane pump which is driven by the vehicle’s engine. As the speed of the engine increases, the pressure in the hydraulic fluid also increases, hence a relief valve is incorporated into the system to allow excess pressure to be bled away.
While the power steering is not being used, i.e. driving in a straight line, twin hydraulic lines provide equal pressure to both sides of the steering wheel gear. When torque is applied to the steering wheel, the hydraulic lines provide unequal pressures and hence assist in turning the wheels in the intended direction.
Some more modern implementations of hydraulic systems also include an electronic pressure valve which can reduce the hydraulic pressure of the power steering lines as the vehicle’s speed increases (Variable assist power steering).
In the DIRAVI system invented by Citroën, the force turning the wheels comes from the car’s high pressure hydraulic system and is always the same no matter what the road speed is. As the steering wheel is turned, the wheels are turned simultaneously to a corresponding angle by a hydraulic ram. In order to give some artificial steering feel, there is a separate hydraulically operated system that tries to turn the steering wheel back to center position.
As long as there is pressure in the car’s hydraulic system, there is no mechanical connection between the steering wheel and the road wheels. This system was first introduced in the Citroën SM in 1970, and was known as ‘VariPower’ in the UK and ‘SpeedFeel’ in the U.S.
While DIRAVI is not the mechanical template for all modern power steering arrangements, it did innovate the now common benefit of speed adjustable steering. The force of the centering device increases as the car’s road speed increases.
Electric Power Steering, such as those found on the Chevrolet Cobalt, Acura NSX, Saturn VUE V6, 2nd gen Toyota MR2 and on most FIAT and Lancia cars, uses electric components. Sensors detect the motion and torque of the steering column and a computer module applies assistive power via an electric motor. This allows varying amounts of assistance to be applied depending on driving conditions. Most notably on FIAT group cars the amount of assistance can be regulated using a button named “CITY” that switches between two different assist curves (boost curve), while on Volkswagen/Audi group cars, the amount of assistance is automatically regulated depending on vehicle speed.
In the event of component failure, a mechanical linkage such as a rack and pinion serves as a back-up in a manner similar to that of hydraulic systems. The software in the computer module enables the flexibility of “tuning” the characteristics of the electric power steering system to suit the preference of the vehicle designers. The “feel” is often set a bit on the light side so a criticism commonly expressed is a lack of steering “feel”.
Electric power steering is limited to smaller vehicles. This is because the 12 volt electrical system is limited to 80 amps of current which, in turn, limits the size of the motor to less than 1 kilowatt. (12.5 volts times 80 amps equals 1000 watts) Vehicles such as trucks and SUVs require a larger power output. A new 42 volt electrical system standard may enable use of electric power steering on larger vehicles.
Electric systems have a slight advantage in fuel efficiency (almost 1 MPG) because there is no hydraulic pump constantly running, whether assistance is required or not, and this is the main reason for their introduction.
Servotronic offers speed-dependent power steering, in which the amount of servo assist depends on road speed and thus provides even more comfort and convenience for the driver. The amount of power assist is greatest at low speeds, for example when parking the car. The greater assist makes it easier to maneuver the car. At higher speeds, an electronic sensing system gradually reduces the level of power assist. In this way, the driver can control the car even more precisely than with conventional power steering. Servotronic is used by a number of automakers including Audi, BMW, and Porsche. Servotronic is a trademark of AM General[1].
So called “hybrid” systems use the same hydraulic assist technology as standard systems, with the hydraulic pressure being provided by an electric motor instead of a belt driven one. Those systems can be found in Volkswagen, Audi, Peugeot, SEAT, Skoda, Suzuki, MINI and some Mazda cars.
ABSTRACT:
Cryogens are effective thermal storage media which, when used for automotive purposes, offer significant advantages over current and proposed electrochemical battery technologies, both in performance and economy. An automotive propulsion concept is presented which utilizes liquid nitrogen as the working fluid for an open Rankine cycle. When the only heat input to the engine is supplied by ambient heat exchangers, an automobile can readily be propelled while satisfying stringent tailpipe emission standards. Nitrogen propulsive systems can provide automotive ranges of nearly 400 kilometers in the zero emission mode, with lower operating costs than those of the electric vehicles currently being considered for mass production. In geographical regions that allow ultra low emission vehicles, the range and performance of the liquid nitrogen automobile can be significantly extended by the addition of a small efficient burner. Some of the advantages of a transportation infrastructure based on liquid nitrogen are that recharging the energy storage system only requires minutes and there are minimal environmental hazards associated with the manufacture and utilization of the cryogenic “fuel.”
INTRODUCTION:
Under present regulations, a Zero Emission Vehicle is one that does not produce any tailpipe pollutants, regardless of the emissions produced in the manufacture of the vehicle or in generating the electricity to recharge its energy storage system. Some of the available technologies for storing energy that meet these qualifications are electrochemical batteries, fuel cells, and flywheels. Improvements in each of these energy storage systems continue to be made; however, only the electrochemical battery has reached a high enough state of development to be considered useful and practical in a large EV fleet. Among the different battery concepts being developed, the lead-acid battery still appears to offer the best compromise of performance, utility, and economy for transportation applications.
A significant fraction of the lead produced each year is used in lead-acid batteries for automobiles and a typical EV requires 20-30 conventional batteries to have a useful range. The growing public awareness of the health hazards arising from elevated concentrations of lead in the environment has resulted in a steady decrease in the amounts of lead used in industry and personal products over the years. In addition, it has been found that the pollution control practices at the mine heads and ore smelters have not prevented serious degradation of their surroundings. Thus, it is highly probable that the environmental impact of the increased mining and refining of lead ore, to meet the needs of a transportation infrastructure based on lead-acid batteries, could completely negate the benefits expected from the elimination of tailpipe emissions. It appears that liquid nitrogen (LN2) can be used in a zero-emission propulsion system that is as effective and probably more economical to operate than the high performance battery systems currently under development.
THEORY BEHIND CRYOCAR:
The basic idea of the LN2 propulsion system is to utilize the atmosphere as a heat source and a cryogen as a heat sink in a thermal power cycle. This is in contrast to typical thermal engines which utilize an energy source at temperature significantly above ambient and use the atmosphere as a heat sink. In both cases the efficiency of conversion of thermal energy of the source to work (W) is limited by the Carnot efficiency, h = W/Qh = 1 - Tl/Th, where Qh is heat input, Tl is the sink temperature, and Th is the temperature of the heat source. By using liquid nitrogen as the cryomobile energy sink (Tl = 77 K) this ideal thermal efficiency is impressively high (74%) with an atmospheric heat source at Th = 300 K. The key issues are the ability to design a practical energy conversion system that can take advantage of this high efficiency and the available energy of the cryogen while still being cost competitive with alternative EVs.
Power Cycle
The Rankine cycle is among the most attractive choices for approximating Carnot performance, when using a fixed temperature heat source and sink.
Fig. 2 Temperature-entropy diagram of Rankine cycle using LN2 for working fluid.
We have focused on directly using the nitrogen itself as the working fluid, wherein the liquid is compressed with a cryogen pump, heated and vaporized by heat exchange with the atmosphere, and then expanded in a piston-cylinder engine. State 1 is the cryogenic liquid in storage at 0.1 MPa and 77 K. The liquid is pumped up to system pressure of 4 MPa (supercritical) at state 2 and then enters the economizer. State 3 indicates N2 properties after its been preheated by the exhaust gas. Further heat exchange with ambient air brings the N2 to 300 K at state 4, ready for expansion. Isothermal expansion to 0.11 MPa at state 5 would result in the N2 exhaust having enough enthalpy to heat the LN2 to above its critical temperature in the economizer, whereas adiabatic expansion to state 6 would not leave sufficient enthalpy to justify its use. The specific work output would be 320 and 200 kJ/kg-LN2 for these isothermal and adiabatic cycles, respectively, without considering pump work. While these power cycles do not make best use of the thermodynamic potential of the LN2, they do provide specific energies competitive with those of lead-acid batteries.
WORKING:
The LN2 propulsion system for a ZEV operates very much like a conventional steam engine while taking advantage of machinery designed for sub ambient temperature applications. Instead of using a steam jacket to minimize the heat loss through the steam cylinder walls, a LN2 expander will have circulating fluid to maintain the wall temperature as high as possible to enhance heat transfer during the power stroke.
A schematic of a Rankine cycle propulsion system using only ambient air to heat the cryogenic working fluid is shown in Fig. 1. An insulated “fuel” tank contains LN2 at atmospheric pressure and a temperature of 77 K. A cryogenic pump draws LN2 from the bottom of the tank and compresses it to the operating pressure of the system.
Pressurized LN2 then passes through the heat exchanger, which is optimized as a LN2 vaporizer and N2 super heater, to raise the gas temperature to just below ambient conditions. The gaseous N2 is then injected into the cylinder as the piston approaches top dead center. It is possible for multiple expansion strokes and reheats to be utilized, at the expense of mechanical complexity, to approach quasi-isothermal performance. If the exhaust gas has sufficient enthalpy it passes through an economizer before being vented to atmosphere. The nitrogen condensation phase closing the Rankine cycle occurs at stationary air liquefaction plants.
This zero emission propulsion concept offers many environmental advantages over internal combustion engines and electrochemical battery vehicles. It has low operating costs, ample propulsive power, and reasonable round trip energy efficiency. We refer to this ZEV as the “cryomobile.”
Application to Automobile Propulsions:
Peak injection pressures of 4 MPa and peak cycle temperature of 300 K are used . Estimates of the mass and volume of the LN2 required for a given range are based on a vehicle that requires the same amount of road power during freeway cruise i.e., 7.8 kW at 97 km/h (60 mi/h). The “fuel” operating costs are based on the economics of supplying LN2 from a plant optimized for its production (2.6¢ per kg-LN2), as discussed in Section II. For the specified cruise conditions, the propulsion system having an isothermal expansion process will consume LN2 at a rate of 25 gm/sec and have an operating cost of approximately 2.4¢ per kilometer. The corresponding storage volume and mass of LN2 required to provide a maximum range of 300 km is 400 liters (106 gal) and 280 kg, respectively. Thus the cryogenic storage tank can readily fit within the trunk volume of a conventional automobile.
Not only are the operating costs of the cryogen propulsion systems lower than those for the EV concepts discussed above, they are also competitive with the advanced battery systems currently being developed. The LN2 storage system compares favorably with the lead-acid battery on a per mass basis. Indeed, if near-isothermal performance can be achieved, the specific energy characteristics become particularly attractive. In addition, since the fully loaded LN2 tank would comprise about 25% of the total vehicle mass (30% is typical mass ratio for lead-acid battery systems), the cryomobile performance should increase as the cryogen is consumed.
Components Of LN2 Vehicle:
Expander:
The maximum work output of the LN2 engine results from an isothermal expansion stroke. Achieving isothermal expansion will be a challenge, because the amount of heat addition required during the expansion process is nearly that required to superheat the pressurized LN2 prior to injection. Thus, engines having expansion chambers with high surface-to-volume ratios are favored for this application. Rotary expanders such as the Wankel may also be well suited. A secondary fluid could be circulated through the engine block to help keep the cylinder walls as warm as possible. Multiple expansions and reheats can also be used although they require more complicated machinery.
Vehicle power and torque demands would be satisfied by both throttling the mass flow of LN2 and by controlling the cut-off point of N2 injection, which is similar to how classical reciprocating steam engines are regulated. The maximum power output of the propulsion engine is limited by the maximum rate at which heat can be absorbed from the atmosphere. The required control system to accommodate the desired vehicle performance can be effectively implemented with either manual controls or an on-board computer. The transient responses of the LN2 power plant and the corresponding operating procedures are topics to be investigated.
Heat Exchanger
The primary heat exchanger is a critical component of a LN2 automobile. Since ambient vaporizers are widely utilized in the cryogenics and LNG industries, there exists a substantial technology base. Unfortunately, portable cryogen vaporizers suitable for this new application are not readily available at this time. To insure cryomobile operation over a wide range of weather conditions, the vaporizer should be capable of heating the LN2 at its maximum flow rate to near the ambient temperature on a cold winter day. For an isothermal expansion engine having an injection pressure of 4 MPa, the heat absorbed from the atmosphere can, in principle, be converted to useful mechanical power with about 40% efficiency. Thus the heat exchanger system should be prudently designed to absorb at least 75 kW from the atmosphere when its temperature is only 0°C.
To estimate the mass and volume of the primary heat exchanger, it was modeled as an array of individually fed tube elements that pass the LN2 at its peak flow rate without excessive pressure drop. Each element is a 10 m long section of aluminum tubing having an outside diameter of 10 mm and a wall thickness of 1 mm. They are wrapped back and forth to fit within a packaging volume having 0.5 m x 0.4 m x 0.04 m dimensions and are arrayed in the heat exchanger duct as shown. Incoming air will pass through a debris deflector and particulate filter before encountering the elements. An electric fan will draw the air through the ducts when the automobile is operating at low velocities or when above normal power outputs are required.
The atmospheric moisture will be removed relatively quickly as the ambient air is chilled over the first few tube rows, leaving extremely dry air to warm up the coldest parts at the rear of the heat exchanger where the LN2 enters. Surface coatings such as Teflon can be used to inhibit ice build up and active measures for vibrating the tube elements may also be applied. However, these approaches may not be necessary since high LN2 flow rates are only needed during times of peak power demand and the heat exchanger elements are much longer than necessary to elevate the LN2 temperature to near ambient at the lower flow rates required for cruise. Thus, the frosted tube rows may have ample opportunity to de-ice once the vehicle comes up to speed.
Cryogen Storage Vessel
The primary design constraints for automobile cryogen storage vessels are: resistance to deceleration forces in the horizontal plane in the event of a traffic accident, low boil-off rate, minimum size and mass, and reasonable cost. Crash-worthy cryogen vessels are being developed for hydrogen-fueled vehicles that will prevent loss of insulating vacuum at closing speeds of over 100 km/h. Moderately high vacuum (10-4 torr) with super insulation can provide boil-off rates as low as 1% per day in 200 liter (53 gal) containers. Using appropriate titanium or aluminum alloys for the inner and outer vessels, a structurally reinforced dewar could readily have a seven-day holding period.
Range Extension and Power Boosting
Range extension and performance enhancement can be realized by heating the LN2 to above ambient temperatures with the combustion of a relatively low pollution fuel such as ethanol or natural gas. The augmentation of power output is most apparent for the adiabatic expansion engine. To evaluate the performance enhancement potential for an isothermal engine, the high temperature N2 is assumed to polytropically expand to the end state reached when the engine is operating isothermally at ambient temperature. In this particular propulsive cycle an extra superheat of 200°C results in only a 30% increase in specific power. Thus the advantage of operating above ambient temperature depends, in part, on how isothermal the expansion process can be made to be.
There is also the intriguing possibility of storing energy for boosting power or extending range by applying a medium that undergoes a phase change to the final super heater segment of the heat exchanger system. Ideally the phase change material would be slowly “recharged” as it absorbs heat from the atmosphere while the vehicle is parked and during cruise when peaking power is not required. Fast recharging with electric heaters may also be considered. We recognize that this added complexity must compete in mass and compactness with the alternative of just carrying more LN2.
While extremely cold weather would degrade performance of a LN2 propulsion system, this would not diminish the cryomobile’s advantage over most battery EVs since their performance is severely compromised in cold weather. Below freezing, air temperatures are extremely warm to the cryogen “fuel” and the moisture content of the atmosphere is significantly diminished. Thus it is anticipated that sufficient enthalpy can still be drawn from the air to provide ample power without incurring a detrimental icing penalty. If necessary, an auxiliary combustor can be added that would allow continuous use of the vehicle on the very coldest days.
COMPARISION WITH EVs:
It is useful to compare the performance capabilities of the LN2 propelled vehicle with two other EV concepts: General Motor’s new electric car called the “Impact” and a Honda CRX that was converted to operate with an advanced electric propulsion system. The Impact is an optimized EV that utilizes advanced lead-acid batteries, special tires for low rolling resistance, and a streamlined body having a very low drag coefficient. This two-seater car contains 400 kg of batteries to get a maximum range of 240 km between recharges and it has an effective operating cost of 5¢/km (8¢/mi). The modified CRX uses a pack of 28 lead-acid batteries, which have a total mass of 500 kg and occupy a volume of 240 liters (63 gal). The maximum range for this EV at cruise is 180 km and its effective operating cost is 28¢/km (45¢/mi). If the CRX were modified with an LN2 propulsion system and the cryogen storage vessel occupied the same volume as the lead-acid batteries, then this vehicle would have the same range while saving 300 kg in energy storage mass.
Our objective with the 5-stroke engine is to develop a gasoline engine with fuel consumption and emission levels comparable to that of current diesel engines, without the serious problem of particulate and NOx emissions that plague diesels.
The engine concept, which was invented by Gerhard Schmitz, has been developed by Ilmor into a working engine using a rapid prototype cast cylinder head, a machined from solid cylinder block and separate electrically powered oil and water pumps. Two overhead camshafts operate the conventional coil spring valvegear with the HP camshaft running at 0.5 x crank speed and the LP camshaft running at 1 x crank speed. The engine is also turbocharged to increase the engine rating.
Principle of operation
The 5-stroke concept engine utilizes two fired cylinders (High Pressure – HP) operating on a conventional 4-stroke cycle which alternately exhaust into a central expansion cylinder (Low Pressure – LP), whereupon the burnt gases perform further work. The LP cylinder decouples the expansion and compression processes and enables the optimum expansion ratio to be selected independently of the compression ratio.
Running of the concept engine has produced impressive fuel consumption readings over a very wide operating range. This is because at the onset of knock a greater percentage of work can be extracted in the LP cylinder, giving a degree of self compensation.
Further development
Having run the proof of concept engine, Ilmor is now looking to produce a second phase development engine for in-vehicle testing. The performance targets for this engine are as follows:
Advantages of the 5-stroke concept
5-stroke performance figures
Ilmor is using its race engine expertise to bring developments to the field of energy efficient engines. Motor racing is not generally associated with fuel economy, but the lessons learned during periods of intense engine development can be applied with great effect to create highly fuel efficient engines.
Fuel efficiency can be improved by downsizing engines – creating the same amount of power from a smaller swept volume (smaller capacity) which typically burns a smaller amount of fuel. High performance engine design is all about extracting as much power as possible from a defined capacity by the use of intelligent design, low friction coatings or even completely new concepts. All of this knowledge can therefore be applied to maximise the power output of a small capacity, fuel efficient engine.
Our flexible approach ensures that we are able to build on a concept and develop innovative, tailored and most importantly working solutions for our clients, allowing physical testing and ongoing development of the concept.
5-stroke concept engine
One such example of this application of our engineering knowledge is the patented 5-stroke engine which Ilmor is currently developing. Our objective with the 5-stroke engine is to develop a gasoline engine with fuel consumption and emission levels comparable to that of current diesel engines, without the serious problem of particulate and NOx emissions that plague diesels.
The simplest way to demonstrate the 5-stroke principle was considered to be a 3 cylinder layout with two fired 4-stroke cylinders (High Pressure – HP) alternately exhausting into a central expansion cylinder (Low Pressure – LP) which provides a further expansion process on the exhaust gases (the 5th stroke).
The engine uses a rapid prototype cast cylinder head, a machined from solid cylinder block and separate electrically powered oil and water pumps. Two overhead camshafts operate the conventional coil spring valvegear with the HP camshaft running at 0.5 x crank speed and the LP camshaft running at 1 x crank speed. The engine is also turbocharged to increase the engine rating.
Reference: www.ilmor.co.uk
