ExcitingAds!
ExcitingAds! Search

Directory A-B C-E F-H I-K L-N O-Q R-T U-W X-Z

 

Site Map

ExcitingAds! Automotive Headlines

↑ Grab this Headline Animator

 

 

Add to Pageflakes

 

 
MAVIC COSMIC CARBONE SL WHEELSET 09
The Mavic Cosmic Carbone SL features a new rim technology that reduces weight, inertia and cost for the same strength and stiffness weighing in at only 1740 grams, the new SL is the best aero wheel you can get for the money.
  • 20 grams lighter rim thanks to a new alloy rim extrusion
  • 12K carbon flanges for frontal and lateral stiffness
  • Straight pull radialy laced spokes for increased stiffness and durability
  • 52 mm elliptic rim flanges
  • Low count bladed spokes
  • Full tire compatibility
  • Efficient, predictable and weatherproof braking without the need for special brake pads
  • Strong, durable and impact resistant rim
  • Braking surface: UB Control
  • Drilling: traditional
  • Eyelet: single
  • Rim Height: 52 mm
  • Rim Joint: SUP
  • Rim Lowering: ISM
  • Rim Material: Maxtal and 12K carbon fiber
  • Valve hole diameter: 6.5 mm
  • Spoke Count: front 16, rear 20
  • Lacing: front radial, rear radial non-drive side, crossed 2 drive side
  • Nipples : ABS, brass
  • Spoke Shape: straight pull, bladed
  • Hub Bearings: QRM+
  • Free wheel mechanism: FTS-L, steel
  • Front and rear axle material: aluminum
  • Front and rear bodies: aluminum
  • Front axle size: 9 x 100
  • Rear axle size: 9 x 130
  • ED10 (Campagnolo) or M10 (Shimano, Sram...)
  • ETRTO size: 622x15c
  • Recommended tire sizes: 19 to 28 mm
  • Tire: clincher
  • Published weight (ED10): 1740 grams per pair, front wheel: 780 grams, rear wheel: 960 grams


Price: 1199.90


MAVIC COSMIC ELITE WHEELSET 09
The Cosmic Elite Wheelset by Mavic is made for flat roads and high speeds, inspired by the Cosmic Carbon SL this is a great wheel for anyone who speed is everything.
  • Profiled rim and bladed spokes deliver great aerodynamics and low frontal drag
  • 30 mm deep rim profile
  • Low spoke count (20/20)
  • Ultra bladed spokes
  • Radial lacing on front and on rear non drive side
  • 30mm deep rim profile
  • Straight pull spokes : stronger than J bent spokes
  • Braking surface: UB Control
  • Drilling: traditional
  • Eyelet: profiled
  • Rim Height: 30 mm
  • Rim Joint: SUP
  • Rim Material: 6106 Aluminum
  • Valve hole diameter: 6.5 mm
  • Spoke Count: 20 front and rear
  • Lacing: front radial, rear radial non-drive side, crossed 2 drive side
  • Spoke Material: stainless steel
  • Nipples : ABS, brass
  • Spoke Shape: straight pull, bladed
  • Bearings: QRM
  • Free wheel mecanism: FTS-L, steel
  • Front and rear axle material: steel
  • Front and rear bodies: aluminum
  • Front axle size: 9 x 100
  • Rear axle size: 9 x 130
  • ED10 (Campagnolo) or M10 (Shimano, Sram...)
  • ETRTO size: 622x15c
  • Recommended tire sizes: 19 to 28 mm
  • Tire: clincher
  • Published weight (ED10): 1900 grams per pair, front wheel: 890 grams, rear wheel: 1010 grams

Price: 499.90


MAVIC R-SYS PREMIUM WHEELSET
The R-SYS Premium wheelset takes the best of R-SYS TraComp technology and features titanium bolts and skewers as well as carbon hub caps to further reduce weight helping to make it perform as good as it looks.
  • TracompTM technology prevents loss of tension on spokes to maintain high stiffness under high loads
  • Maximized rear wheel dish increases lateral stiffness
  • Carbon spokes don't stretch as much as steel or aluminum ones which limit wheel deflection
  • Braking surface: UB Control
  • Rim Drilling: Fore
  • Rim Height: front 22 mm, rear 25 mm asymetrical
  • Joint: SUP
  • Lowering: ISM
  • Material: Maxtal
  • Valve hole diameter: 6.5 mm
  • Rim Count: front 16, rear 20
  • Lacing: front radial, rear radial non-drive side, crossed 2 drive side
  • Shape: inflexible tubular, Tracomp technology
  • Bearings: QRM+
  • Free wheel mecanism: FTS-L, steel
  • Front axle size: 9 x 100
  • Front axle: aluminum
  • Rear axle size: 9 x 130
  • Rear axle: titanium and aluminum
  • ED10 (Campagnolo) or M10 (Shimano, Sram...)
  • ETRTO size: 622x15c
  • Recommended tire sizes: 19 to 28 mm
  • Tire: clincher
  • Published weight (ED10): 1360 grams per pair, front wheel: 575 grams, rear wheel: 785 grams


Price: 1499.90


SHIMANO DURA-ACE CARBON TUBELESS WHEEL
The Shimano Dura Ace WH-7850-C24-CL Carbon Wheelset is alightweight and stiff wheelset is the choice of Pro-Tour Sprinters and Time Trial specialists.
  • Proprietary Shimano carbon construction
  • Aerodynamic 28mm and 24mm section rims
  • New titanium freehub body w/quick engagement
  • New wider flange hubs and offset rear rim for increased rigidity and power transmission
  • Shimano quality proven angular contact bearings with oversize 7075 alloy axles
  • Brake Type: Rim brake
  • Freehub Body Material: Titanium
  • Cassette Compatibility: 8/9/10-speed
  • Over Locknut: 100mm, 130mm
  • Axle Type: Quick Release
  • QR Skewer Length: 133mm, 163mm
  • Axle Length: 108mm, 141mm
  • Axle Material: Aluminum
  • Contact Seal: Yes
  • Hub Shell Material: Aluminum
  • Hub Shell Finish: Anodized
  • QR Lever Material: Aluminum
  • QR Lever Finish: Anodized
  • Rim Type: Tubular
  • Rim Size: 700C rear offest
  • Rim Material: CFRP
  • Rim Finish: Carbon
  • Rim Height: 28mm, 24mm
  • Rim Width: 20.8mm
  • Spokes: 16(front), 20(rear)
  • Spoke Gauge/Shape: butted(2.0/1.5/2.0) bladed(front), RH:butted(2.0/1.8/2.0)bladed LH:butted(2.0/1.5/2.0) bladed(rear)
  • Spoke Material: Stainless steel
  • Spoke Color: lon plating
  • Nipple Material: Aluminum
  • Nipple Color: Red
  • Average Weight: 592g(front), 794g(rear) Weight does not include quick release

Price: 549.99

SHIMANO DURA-ACE CARBON CLINCHER WHEELS
The Shimano Dura Ace WH-7850-C24-CL Carbon Clincher Wheelset is a lightweight and stiff wheelset that gives you the performance of a Pro-Tour wheel with the convenience of clinchers.
  • Patent pending Shimano carbon-alloy composite construction
  • Aerodynamic 24mm profile rims
  • New titanium freehub body w/quick engagement
  • New wider flange hubs and offset rear rim for increased rigidity and power transmission
  • Shimano quality proven angular contact bearings with oversize 7075 alloy axles
  • Brake Type: Rim brake
  • Freehub Body Material: Titanium
  • Cassette Compatibility: 8/9/10-speed
  • Over Locknut: 100mm, 130mm
  • Axle Type: Quick Release
  • QR Skewer Length: 133mm, 163mm
  • Axle Length: 108mm, 141mm
  • Axle Material: Aluminum
  • Contact Seal: Yes
  • Hub Shell Material: Aluminum
  • Hub Shell Finish: Anodized
  • QR Lever Material: Aluminum
  • QR Lever Finish: Anodized
  • Rim Type: Clincher
  • Rim Size: 622x15C (700C) rear offest
  • Rim Material: CFRP/aluminum
  • Rim Finish: Carbon/alloy
  • Rim Height: 24mm, 23mm
  • Rim Width: 20.8mm, 20.8mm
  • Spokes: 16(front), 20(rear)
  • Spoke Gauge/Shape: butted(2.0/1.5/2.0) bladed(front), RH:butted(2.0/1.8/2.0)bladed LH:butted(2.0/1.5/2.0) bladed(rear)
  • Spoke Material    stainless steel    stainless steel
  • Spoke Color    Black    Black
  • Nipple Material    aluminum    aluminum
  • Nipple Color    Red    Red
  • Average Weight    592g    794g
  • Note    Weight does not include quick release

Price: 524.99

SHIMANO DURAACE SCANDIUM TUBELESS WHEELS
The Dura-Ace WH-7850-SL Scandium Wheelset features Road Tubeless Technology, helping to keep you rolling even when you roll over debris that would pop your tube.
  • Road Tubeless technology
  • Tube and tubeless tire compatible wheels
  • Patent Pending light, strong and durable "butted" Scandium alloy rim
  • New titanium freehub body w/quick engagement
  • New wider flange hub and offset rim for increased rigidity and power transmission
  • Shimano quality proven angular contact bearings with oversize 7075 alloy axles
  • Rim wear indicator allows safe detection of worn rim
  • Brake Type: Rim brake
  • Freehub Body Material: Titanium
  • Cassette Compatibility: 8/9/10-speed
  • Over Locknut: 100mm, 130mm
  • Axle Type: Quick Release
  • QR Skewer Length: 133mm, 163mm
  • Axle Length: 108mm, 141mm
  • Axle Material: Aluminum
  • Contact Seal: Yes
  • Hub Shell Material: Aluminum
  • Hub Shell Finish: Anodized
  • QR Lever Material: Aluminum
  • QR Lever Finish: Anodized
  • Rim Type: Clincher/UST
  • Rim Size: 622x15C (700C), rear offest tubeless
  • Rim Material: Scandium alloy
  • Rim Finish: Anodized
  • Rim Height: 24mm, 23mm
  • Rim Width: 20.8mm
  • Spokes: 16, 20
  • Spoke Gauge/Shape: butted(2.0/1.5/2.0)bladed(front), RH:butted(2.0/1.8/2.0)bladed LH:butted(2.0/1.5/2.0)bladed(rear)
  • Spoke Material: Stainless steel
  • Nipple Material: Aluminum
  • Nipple Color: Red
  • Published Average Weight: 649g(front), 865g(rear)(Weight does not include quick release or valve stem)


Price: 449.99

WTB LASERDISC TRAIL 29ER WHEEL '08
The LaserDisc 29'er wheelset is a strong set with 27-millimeter-wide LaserDisc Trail29″ rims, 28 WTB double-butted spokes and LaserDisc Lite hubs,these wheels are light enough for the racecourse yet strong enough foraggressive trail riding.
  • Laserdisc trail 29'er rim
  • Laserdisc Lite 28h hub
  • Alloy nipples
  • 3 cross lacing pattern
  • Weight(claimed):
    • Front: 950 g
    • Rear: 970 g
    • Rear SS: 1170 g

Price: 189.95


EASTON XC ONE DISC WHEELSET '08
The Easton XC One was designed with the most demanding XC riders in mind, it is up to 10% lighter than competing wheels and as much as 36% stiffer. This means you will have superior control, and self-adjusting preload makes for easy setup and eliminates wheel wobble. Bullet-proof rear hub offers durability and long life. Precision, oversized U.S. bearings make for smooth operation and maximum dependability.
  • Weight(Pair): 1590 g
  • Rims: Easton XC disc, 23 mm box style
  • Spokes: stainless steel straight pull, black coating. 2.0/1.7 diameter with allow nipples.
  • Spoke Count: 24 spoke, 2-cross, F/R
  • Features: V-Max sealed cartridge bearings
  • Six-bolt international disc standard
  • Aluminum freehub body
  • 8/9 speed compatible

Price: 349.00


TYR WOMENS SOLID 4" SHORT
TYR Solid Shorts
 
Item Specifications
Color Black
Fit Women''s
Size Large
Shorts Style Unspecified

Price: 24.00


CAMPY RECORD QS 10S ERGOPOWER LEVER SET
It doesn't come any better than Record. Integrated shift/brake levers for use with 10 speed Campagnolo drivetrains. New revision with "QS" QuickShift technology, allowing faster operation of the front derailleur.
  • Includes Campy cables and housing
  • Compatible with (optional) Ergobrain cyclecomputer
  • Left lever handles double or triple crankset
  • Right lever works with Campy 10 speed rear derailleurs
  • Weight-saving lever blades

Price: 396.00


CRAFT SHORT SLEEVE CREW

Craft Short-sleeve base layer shirts have raglan shoulders and seamless construction for a great looking fit.

Features and Information

  • Raglan shoulders
  • Seamless construction

Price: 30.90


OAKLEY WOMEN TRAIL JERSEY '08
The Trail Jersey is is a comfortable jersey that offers a quick-drying polyester construction that wicks away moisture while providing UV protection. Structured fabric improves ventilation while moisture wicking action pulls perspiration to the surface where it can evaporate. The fit is relaxed and ready to rock the trail.
  • 100% polyester
  • Quick-drying material with moisture wicking and UV protection
  • Mesh structured fabric for ventilation
  • Screen print accent on front and icon on back


Price: 21.00


BELLWETHER WOMEN VENUS SS JERSEY
Bellwether Venus Women's Short Sleeve jersey combines technical performance with flare to match and all in one comfortable package.
  • 8" locking front zipper
  • 2 larger rear pockets
  • Elastic free waist and cuffs
  • Club fit
  • Tectra-lite fabrication
  • Season: Warm Weather
  • Material: Tectra-lite
  • Fit: Women's
  • Zipper: 1/4 Zip


Price: 37.86


OAKLEY TRAIL ZIP JERSEY '08
The Trail Zip Jersey is a relaxed fit jersey that gives you room to maneuver without being to big, it comes with the premium features like moisture wicking, UV protection, and even a side-access back pocket that zips shut.
  • 100% polyester in quick drying, moisture wicking fabric with UV protection
  • Mesh structured side panels for ventilation
  • Quarter-zip closure with corded zipper pull
  • Smooth structured front and back panel for proper drape
  • Flatlock stitching and saddle sleeves for comfort and freedom of movement
  • Security back pocket with corded zipper pull
  • Icon accent on front and back


Price: 39.00


RETRO IMAGE CYCLES BRILLANT JERSEY
Based on a 1923 poster for "Cycles Brilliant", combining elements of Surrealism and Cubism.
  • Designed for warm weather with Euro Mesh fabric
  • Short sleeves
  • 3/4 front zipper

Price: 48.60


RETRO IMAGE APPAREL WMN BETTY BOOP JERSY
The Retro Image Apparel Women's Betty Boop jersey is a cool and comfortable 3/4 zip jersey. Betty Boop first appeared in the 6th Talkartoon starring Bimbo, entitled "Dizzy Dishes" (1930). Grim Natwick was the first animator to draw Betty, who had not yet been officially named. He took inspiration for Betty's spit curls from a song sheet of Helen Kane, "Boop Oop a Doop Girl." Her first starring role was in "Betty Coed" (1931), which marked the first time the name Betty was connected with the character. In 1934, Betty began appearing in comic strips drawn by Bud Counihan (though they were signed with Max Fleischer's name).
Material: Euro Mesh
  • Women's Short Sleeved, 3/4 Zip
Note: These jeresys tend to run small

Price: 48.60


WORLD JERSEYS TEAM CERVEZA JERSEY
World's warm-weather jerseys let you add a visual flair to your ride. Polyester Euro-Mesh construction keeps you cool and is easy to care for.
  • 3/4 front zip
  • short sleeve

Price: 39.00


TROY LEE S/S MOTO JERSEY '08
The Troy Lee Designs Short Sleeve Moto Jersey is tops in comfort with a super stretch 100% polyester construction.
  • Super stretch 100% polyester construction for ultimate comfort and durability
  • Crew collar with cotton/polyester stretch material
  • Mesh raglan sleeves and athletic cut


Price: 24.62


 

Automobile

An automobile or motor car is a wheeled motor vehicle for transporting passengers, which also carries its own engine or motor. Most definitions of the term specify that automobiles are designed to run primarily on roads, to have seating for one to eight people, to typically have four wheels, and to be constructed principally for the transport of people rather than goods.[1] However, the term "automobile" is far from precise, because there are many types of vehicles that do similar tasks.

Automobile comes via the French language, from the Greek language by combining auto [self] with mobilis [moving]; meaning a vehicle that moves itself, rather than being pulled or pushed by a separate animal or another vehicle. The alternative name car is believed to originate from the Latin word carrus or carrum [wheeled vehicle], or the Middle English word carre [cart] (from Old North French), and karros; a Gallic wagon.[2][3]

As of 2002, there were 590 million passenger cars worldwide (roughly one car per eleven people).[4]

Contents

[hide]

History

Although Nicolas-Joseph Cugnot is often credited with building the first self-propelled mechanical vehicle or automobile in about 1769 by adapting an existing horse-drawn vehicle, this claim is disputed by some, who doubt Cugnot's three-wheeler ever ran or was stable. Others claim Ferdinand Verbiest, a member of a Jesuit mission in China, built the first steam-powered vehicle around 1672 which was of small scale and designed as a toy for the Chinese Emperor that was unable to carry a driver or a passenger, but quite possibly, was the first working steam-powered vehicle ('auto-mobile').[5][6] What is not in doubt is that Richard Trevithick built and demonstrated his Puffing Devil road locomotive in 1801, believed by many to be the first demonstration of a steam-powered road vehicle although it was unable to maintain sufficient steam pressure for long periods, and would have been of little practical use.

In Russia, in the 1780s, Ivan Kulibin developed a human-pedalled, three-wheeled carriage with modern features such as a flywheel, brake, gear box, and bearings; however, it was not developed further.[7]

François Isaac de Rivaz, a Swiss inventor, designed the first internal combustion engine, in 1806, which was fueled by a mixture of hydrogen and oxygen and used it to develop the world's first vehicle, albeit rudimentary, to be powered by such an engine. The design was not very successful, as was the case with others such as Samuel Brown, Samuel Morey, and Etienne Lenoir with his hippomobile, who each produced vehicles (usually adapted carriages or carts) powered by clumsy internal combustion engines.[8]

In November 1881 French inventor Gustave Trouvé demonstrated a working three-wheeled automobile that was powered by electricity. This was at the International Exhibition of Electricity in Paris.[9]

Although several other German engineers (including Gottlieb Daimler, Wilhelm Maybach, and Siegfried Marcus) were working on the problem at about the same time, Karl Benz generally is acknowledged as the inventor of the modern automobile.[8]

An automobile powered by his own four-stroke cycle gasoline engine was built in Mannheim, Germany by Karl Benz in 1885 and granted a patent in January of the following year under the auspices of his major company, Benz & Cie., which was founded in 1883. It was an integral design, without the adaptation of other existing components and including several new technological elements to create a new concept. This is what made it worthy of a patent. He began to sell his production vehicles in 1888.

Sunday, November 23, 2008

Two-wheeled motorvehicle policy

Community Action for Sustainable Transport - Draft 18.11.2008

This policy uses some strategies first developed by Motorcycling Australia.

Background


For trips where public transport, walking and cycling are not good options people should consider using a two-wheeled motor vehicle (TWMV) rather than a car.

Switching from a car to a motorcycle, scooter or electric bike is an easy way for people to reduce congestion, greenhouse emissions and save money on fuel.

TWMVs make more efficient use of fuel, road space and parking space than a single occupant car and can play a part in the campaign to reduce congestion and climate change.

Statistics on fuel efficiency are available here

When driven below the speed limit TWMVs also pose less of a safety risk to other road users than cars, trucks and buses due to their weight.

TWMVs are a more affordable transport option than driving a single occupant car, and will also help preserve oil reserves for essential agricultural, medical and transport uses.

All levels of Government should be doing more to encourage people to switch from their car to TWMVs.


Proposed strategies

More free parking spaces for TWMVs at activity centres and public transport nodes. Parking must be safe, conveniently located and ensure pedestrian, wheelchair and cyclist access is not obstructed. Car parks should be reclaimed for TWMV parking where possible.

Inclusion of two-wheeled motor vehicles in National Road Transport policies

Reduction in registration fees for TWMVs

Provision of TWMV-only lanes on key arterial roads

Exemption from tolls on tolled roads and infrastructure for TWMVs

Mandatory TWMV parking to be included in the construction plans for new buildings

Integration of TWMVs into the planning for Public Transport projects, such as park and ride for bikes.

A national standard that restricts the speed of new TWMVs available for the general public to 120km/hr

Advertising campaigns to encourage people to switch from a car to a two-wheeled motor vehicle

Government purchase of electric bicycles for use by employees and citizens

Fuel efficiency, in its basic sense, is the same as thermal efficiency, meaning the efficiency of a process that converts chemical potential energy contained in a carrier fuel into kinetic energy or work. Overall fuel efficiency may vary per device, which in turn may vary per application, and this spectrum of variance is often illustrated as a continuous energy profile. Non-transportation applications, such as industry, benefit from increased fuel efficiency, especially fossil fuel power plants or industries dealing with combustion, such as ammonia production during the Haber process. The United States Department of Energy and the EPA maintain a Web site with fuel economy information, including testing results and frequently asked questions.

In the context of transportation, "fuel efficiency" more commonly refers to the energy efficiency of a particular vehicle model, where its total output (range, or "mileage" [U.S.]) is given as a ratio of range units per a unit amount of input fuel (gasoline, diesel, etc.). This ratio is given in common measures such as "liters per 100 kilometers" (L/100 km) (common in Europe and Canada or "miles per gallon" (mpg) (prevalent in the USA, UK, and often in Canada, using their respective gallon measurements) or "kilometres per litre"(kmpl) (prevalent in Asian countries such as India and Japan). Though the typical output measure is vehicle range, for certain applications output can also be measured in terms of weight per range units (freight) or individual passenger-range (vehicle range / passenger capacity).

This ratio is based on a car's total properties, including its engine properties, its body drag, weight, and rolling resistance, and as such may vary substantially from the profile of the engine alone. While the thermal efficiency of petroleum engines has improved in recent decades, this does not necessarily translate into fuel economy of cars, as people in developed countries tend to buy bigger and heavier cars (i.e. SUVs will get less range per unit fuel than an economy car).

Hybrid vehicle designs use smaller combustion engines as electric generators to produce greater range per unit fuel than directly powering the wheels with an engine would, and (proportionally) less fuel emissions (CO2 grams) than a conventional (combustion engine) vehicle of similar size and capacity. Energy otherwise wasted in stopping is converted to electricity and stored in batteries which are then used to drive the small electric motors. Torque from these motors is very quickly supplied complementing power from the combustion engine. Fixed cylinder sizes can thus be designed more efficiently.

Contents

[hide]

[edit] Energy-efficiency terminology

"Energy efficiency" is similar to fuel efficiency but the input is usually in units of energy such as British thermal units (BTU), megajoules (MJ), gigajoules (GJ), kilocalories (kcal), or kilowatt-hours (kW·h). The inverse of "energy efficiency" is "energy intensity", or the amount of input energy required for a unit of output such as MJ/passenger-km (of passenger transport), BTU/ton-mile (of freight transport, for long/short/metric tons), GJ/t (for steel production), BTU/(kW·h) (for electricity generation), or litres/100 km (of vehicle travel). This last term "litres per 100 km" is also a measure of "fuel economy" where the input is measured by the amount of fuel and the output is measured by the distance travelled. For example: Fuel economy in automobiles.

Given a heat value of a fuel, it would be trivial to convert from fuel units (such as litres of gasoline) to energy units (such as MJ) and conversely. But there are two problems with comparisons made using energy units:

  • There are two different heat values for any hydrogen-containing fuel which can differ by several percent (see below). Which one do we use for converting fuel to energy?
  • When comparing transportation energy costs, it must be remembered that a kilowatt hour of electric energy may require an amount of fuel with heating value of 2 or 3 kilowatt hours to produce it.

[edit] Energy content of fuel

The specific energy content of a fuel is the heat energy obtained when a certain quantity is burned (such as a gallon, litre, kilogram). It is sometimes called the "heat of combustion". There exists two different values of specific heat energy for the same batch of fuel. One is the high (or gross) heat of combustion and the other is the low (or net) heat of combustion. The high value is obtained when, after the combustion, the water in the "exhaust" is in liquid form. For the low value, the "exhaust" has all the water in vapor form (steam). Since water vapor gives up heat energy when it changes from vapor to liquid, the high value is larger since it includes the latent heat of vaporization of water. The difference between the high and low values is significant, about 8 or 9%.

In thermodynamics, the thermal efficiency (\eta_{th} \,) is a dimensionless performance measure of a thermal device such as an internal combustion engine, a boiler, or a furnace, for example. The input, Q_{in} \,, to the device is heat, or the heat-content of a fuel that is consumed. The desired output is mechanical work, W_{out} \,, or heat, Q_{out} \,, or possibly both. Because the input heat normally has a real financial cost, a memorable, generic definition of thermal efficiency is[1]

\eta_{th} \equiv \frac{\text{What you get}}{\text{What you pay for}}.

From the first law of thermodynamics, the output can't exceed what is input, so

0 \le \eta_{th} \le 1.0.

When expressed as a percentage, the thermal efficiency must be between 0% and 100%. Due to inefficiencies such as friction, heat loss, and other factors, thermal efficiencies are typically much less than 100%. For example, a typical gasoline automobile engine operates at around 25% thermal efficiency, and a large coal-fueled electrical generating plant peaks at about 46%. The largest diesel engine in the world peaks at 51.7%. In a combined cycle plant, thermal efficiencies are approaching 60%.[2]

Contents

[hide]

[edit] Heat engines

When transforming thermal energy into mechanical energy, the thermal efficiency of a heat engine is the percentage of heat energy that is transformed into work. Thermal efficiency is defined as

\eta_{th} \equiv \frac{W_{out}}{Q_{in}} = 1 - \frac{Q_{out}}{Q_{in}}

[edit] Carnot efficiency

The second law of thermodynamics puts a fundamental limit on the thermal efficiency of heat engines. Surprisingly[citation needed], even an ideal, frictionless engine can't convert anywhere near 100% of its input heat into work. The limiting factors are the temperature at which the heat enters the engine, T_H\,, and the temperature of the environment into which the engine exhausts its waste heat,T_C\,, measured in the absolute Kelvin or Rankine scale. From Carnot's theorem, for any engine working between these two temperatures:

\eta_{th} \le 1 - \frac{T_C}{T_H}\,

This limiting value is called the Carnot cycle efficiency because it is the efficiency of an unattainable, ideal, lossless (reversible) engine cycle called the Carnot cycle. No heat engine, regardless of its construction, can exceed this efficiency.

Examples of T_H\, are the temperature of hot steam entering the turbine of a steam power plant, or the temperature at which the fuel burns in an internal combustion engine.

 

 

 

Automobile

 

 

Auto Loans from up2drive

 

Ensure optimum performance in your car with premium grade auto parts from US Auto Parts.

 

GeekSpeak 300x250

 

Instant Auto Title Loans

 

AutoSport Automotive Outfitters (180x150)

 

Save $30 off $399 + Free Shipping* w/code SAVE30. Valid thru 1/31/2009. Restrictions apply.

 

 

Filing Cabinets on Sale at BettyMills

Privacy Statement Advertise with us All rights reserved ExcitingAds® 1998-2008