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BORAH MICRO JERSEY

The Borah Men's Micro Jerseys have two back pockets for all your essentials, a 9" front zipper for ventilation.

Features and Information

  • ABS Micro Mesh fabric
  • 9" front zipper for extra ventilation
  • Two back pockets for all your essentials
Item Specifications
Color Red
Sleeve Style Short Sleeved
Zipper Travel Half Travel
Season Warm Weather
Material ABS performance Fabric
Fit
Men's

Price: 26.13


DIA-COMPE 990

The Dia-Compe 990 U-Brake is one of the best for freestyle bmx riding.

Item Specifications
Color Black
Brake Reach 0 mm
Brake Lever Actuation Short Pull
Weight 274 g

Price: 21.45


RACEFACE REVOLUTION STEMS
RaceFace Revolution Stem is highly engineered to maximize stiffness and minimize weight. Featuring Gucci 7050 aluminum alloy, and designed to allow riders to use Revolution with a negative rise.
  • Weight: 140 g(claimed)
  • Bar Clamp Diameter: 31.8 mm
  • Stem Angle: 84, 96 deg
  • Stem Length: 70 - 130 mm
  • Steerer Tube: 1-1/8" Threadless


Price: 48.40


RACE FACE RALLY DH ARM ARMOR

The Race Face Rally DH Pads have vented hardshells with perforated 15mm foam for added protection and comfort.

  • Vented hardshell with perforated 15mm foam for protection and comfort
  • Open back enhances venting and comfort


Price: 29.70


DT SWISS CHAMPION 1.8 SILVER SPOKES
DT Swiss spokes are well-known as the "gold standard". Their 15g Champion model is a lightweight, straight gauge design that's a good choice for bikes where weight is at a premium.
  • 32 spokes in 260mm length weighs 190g
  • Spokes include matching DT Swiss brass nipples


Price: 38.50


ADIDAS THE SHIELD GLASSES

Adidas The Shield Sunglasses have Flex zones and a Traction grip.

Features and Information

  • Flex zones
  • SPX
  • Quick-release hinge
  • Traction grip
  • 9-base decentered anti-fog

Price: 55.00


FLYBIKES SPANISH BB BEARINGS (PAIR)
Flybikes Spanish BB 22mm Bearings for cranks with 22mm spindles.

Price: 10.00


FULCRUM EXTERNAL CUPSET ULTRA TORQUE
Fulcrum External Cupset Ultra Torque BSC  for a Bottom Bracket Shell Width of 68 mm.
  • BB Shell Width: 68 mm
  • BB Thread Type: English
  • Spindle Interface Type: Ultra-Torque

Price: 31.79


JAMIS DAKOTA SPORT BIKE 2008
The Dakota Sport is a quick and efficient hardtail XC bike, thanks in part to a short chainstay that makes this bike a great sprinter and also helps to give you great climbing traction.
  • 7005 triple-butted “Superlight” aluminum main tubes, alloy monostay, over-sized seat tuve, gusseted down tube, replaceable derailleur hanger
  • Rock Shox Tora 302 Coil fork, TurnKey lock-out, preload and rebound external adjustors, magnesium lowers, 100mm travel
  • Aheadset headset, Zero-Stack, 1 1/8”
  • WTB Speed Disc rims with eyelets, 32H, with Shimano M495 centerLock disc hubs, WTB 14g stainess
  • WTB MotoRaptor tires, 26” x 2.1, wire bead
  • Shimano Shadow Deore XT rear, Deore 31.8mm top pull front derailleurs
  • Shimano Deore Rapidfire Plus-SL shifters
  • KMC Z-9000 chain
  • SRAM Powerglide 950 cassette 9-speed, 11-32
  • Shimano Deore crankset 44/32/22, 170mm (15.5”), 175mm (17-21”)
  • Shimano ES25 Octalink bottom bracket, 68 x 113
  • FDP clipless pedals
  • Shimano M485 hydraulic disc brakes with 160mm rotors
  • Easton EA30 XC flat bar, 5° sweep x 580mm wide31.8 (OS)
  • Easton EA30 stem 6° x 90mm (15.5 ), 105mm (17”), 120mm (19-21”) extensions, 31.8 (OS)
  • WTB Trail dual compound grips
  • Easton EA30 micro-adjust seatpost, 350mm x 31.6mm with alloy clamp and QR seatpin
  • WTB Speed V Sport SE saddle with SL top and steel rails
  • Published weight: 28.75 lbs.


Inches/Millimeters

Allbikes come with JenonUSA's complementary Free Pro Build Service, pleaseallow 3 business days for your bike to be assembled, inspected andpacked before shipping.


Price: 899.00


JAMIS DIABLO 2.0 BIKE 2007
The Diablo 2.0 is a built for big hits and big air, with a super-strong hydro-formed frame and a double crankset this is a freeride bike that can still climb.
  • 7005 aluminum, 1.5" head tube, 83mm BB shell, 150mm x 12mm thru axle dropout spacing, cartridge bearing pivots, 175mm travel frame
  • Manitou Swinger X4 coil shock
  • Manitou Travis Single Intrinsic Fork, Intrinsic damping, external rebound and compression adjust, with 20mm no-tools hex axle,180mm travel
  • FSA Orbit Extreme Pro, 1.5" Headset
  • Mavic EX823 Maxtal SUP/UST rims, eyeletted, 32H, WTB Laser Disc Super Duty disc hubs (150mm x 20mm thru axle rear), WTB 14G stainless steel spokes
  • Maxxis High Roller UST tubeless tires, 26 x 2.70" front and 2.5" rear
  • SRAM X9 rear, Shimano Saint 31.8mm top pull front derailleurs
  • SRAM X9 Impulse trigger-shifters, 18-speed
  • Shimano HG-93  Chain
  • SRAM PowerGlide 970 Cassette, 9-speed, 11-34
  • TruVativ Holzfeller Crankset, 36/24 with polycarbonate rock guard, 170mm (15.5") , 175mm (17.5 Ð 19.5"")
  • TruVativ Howitzer Team Bottom Bracket for 83mm shell and 57.mm CL
  • Crank Brothers 5050 sealed bearing platform pedals with replaceable plates and pedal spikes
  • Hayes El Camino hydraulic disc brakes with V8 rotors, El Camino levers
  • TruVativ Hussefelt 31.8mm riser bar, 35mm rise x 680mm wide
  • TruVativ Holzfeller Stem 1.5, 6D x 55mmWTB MotoTec clamp-on, DNA compound
  • Titec El Norte Pyro-Scooper telescoping seatpost adjustable 270 - 420mm x 31.6mm with alloy clamp and QRWTB
  • Power V Race DH saddle, black diamond cover, TKL corners and 8mm cromo rails
  • Published Weight: 42.25 lbs


Price: 1999.00


JAMIS DAKAR XAM 2.0 BIKE 2007
The Dakar XAM 2.0 is an agile bike that uses and active suspensions system that soaks up the big hits while still giving you a plush ride on the small stuff making this a bike that is equal part climber and descender.
  • Kinesium alloy main triangle and 7005 rear stays, cartridge bearing pivots, fully-active XAM linkage design, 130mm travel Fox DHX Air 5.0 shock, replaceable derailleur hanger
  • Fox 32 Talas-RLC fork, air spring, rebound & compression adjustors with lockout, 100 - 140mm adjustable travel
  • FSA Orbit Z headset internal cup type, 1 1/8"
  • Mavic XM317 eyeletted disc rims, 32H, with Shimano Deore M525 disc hubs, WTB 14g stainless steel spokes
  • Maxxis High Roller tires 26 x 2.35", folding
  • Shimano XTR (hi-normal) rear, Deore XT 31.8mm top pull front derailleurs
  • Shimano Deore XT Rapidfire Plus-SL, 27-speed shifters
  • Shimano HG-93 chain
  • SRAM Powerglide 970 cassette, 9-speed, 11-34
  • Shimano Deore XT crankset, 44/32/22, 170mm (15"), 175mm (17-21")
  • Shimano Deore XT integrated bottom bracket
  • Crank Brothers Candy C clipless pedals
  • Hayes El Camino hydraulic disc brakes with V7 front and V6 rear rotors, Hayes levers
  • Easton EA70 31.8 MonkeyBar bar, 8D sweep x mid-rise x 635 wide
  • Easton Vice All Mountain 31.8 stem, 6D rise x 85mm (15-17") and 100mm (19-21") extensions
  • WTB MotoTec clamp-on grips DNA compound
  • Easton Havoc micro-adjust seatpost, 30.9mm x 350mm
  • WTB Pure V Race FR saddle, SL top and sides, kevlar corners, cromo rails
  • Published Weight: 31.25 lbs


Inches/Millimeters

Allbikes come with JenonUSA's complementary Free Pro Build Service, pleaseallow 3 business days for your bike to be assembled, inspected andpacked before shipping.


Price: 1799.00


JAMIS CODA SUPREME BIKE 2007
The Coda Supreme is a flat bar road bike that is in a class of it's own, with a classic steel and carbon fiber frame mixing old world style with new world technology. The Coda Supreme offers a superb ride quality and crisp handling, with it's adjustable rise stem it also offers you several ride positions.
  • Carbon fiber top tube, seat tube and seatstays, Reynolds 853 seamless air-hardened down tube, extended head tube with reinforced collars, heat-treated cromo chainstays
  • Easton EC70 Aero fork, carbon fiber blades, alloy steerer
  • Aheadset alloy headset, 1 1/8"
  • Mavic Aksium 700C wheelset, 20/24H UB Control rims, QRM sealed cartridge/FTS-L hubs, stainless steel spokes
  • Vittoria Zaffiro tires, 700 x 25c
  • Shimano Ultegra SS rear, Shimano R770 28.6mm band clamp front derailleurs
  • Shimano SL-R770 for flat-bar Shifters, 20-speed
  • Shimano CN-5600 Chain
  • Shimano CS-5600 Cassette, 10-speed, 11-25
  • FSA Gossamer MegaExo Compact Crankset, 50/34, 170mm (16, 17.5"), 175mm (19.5, 23")
  • FSA MegaExo Bottom Bracket, external bearing
  • Pedals NOT included
  • Tektro R530 dual pivot calipers with Avid FR5 flat bar levers
  • Jamis Carbon reinforced flat bar, 5D bend x 580mm wide
  • Ritchey Pro Adjustable Stem, 100mm (16-17.5"), 120mm (19.5-23")
  • WTB Street Smart Grips with reflective end plugs
  • Ritchey Pro Carbon Seatpost, 250mm x 27.2mm, alloy clamp with cro-moly seatpin
  • Selle San Marco Ischia Saddle
  • Published Weight: 19.25 lbs


Price: 1139.00


INTENSE BMX PRO 24 ALLOY BIKE 09
The Intense BMX Pro 24 Alloy is a fast and agile BMC Cruiser bike with a killer build.
  • 21.25" Alloy Frame
  • SINZ Chromoly Race Fork 1 1/8 Steerer
  • 1-1/8" Threadles Alloy Cap Headset
  • SINZ Hi Ten Pro Size Handlebar
  • SINZ Alloy Stem
  • SINZ Pro Sticky Grips
  • SINZ BMX Race Saddle
  • SINZ Steel Post
  • DNP 18 tooth Freewheel
  • SINZ Tubular 3 piece 175mm Cransket
  • AM Steel Bearings Bottom Bracket Set
  • BMX Steel 41 tooth 1/8" Chainwheel
  • SINZ Alloy Linear Brake
  • AINZ Alloy Brake Lever
  • Deluxe Casing Brake Cable
  • SINZ Alloy Platform Pedals
  • KMC 1/2 x 1/8 Chain
  • SINZ Alloy 36 hole Front, Rear Hub
  • SINZ 36 Holes 24x1.75 Rim
  • ITS Haalo's 20x1.75 Tires

Price: 299.99


INTENSE BMX PRO 20 ALLOY BIKE 09
The Pro 20 Alloy BMX Race bike is a strong and durable BMX bike that will help you get to the front.
  • 21.5" Alloy Frame
  • SINZ Chromoly Race Fork 1 1/8 Steerer
  • 1 1/8 Threadles Alloy Cap Headset
  • SINZ HiTen Pro Size Handlebar
  • SINZ Alloy Stem
  • SINZ Pro Sticky Grips
  • SINZ BMX Race Saddle
  • SINZ Steel Post
  • DNP 16 tooth Freewheel
  • SINZ Tubular 3 piece 170mm Crankset
  • AM Steel Bearings Bottom Bracket Set
  • BMX Steel 43 tooth 1/8" Chainwheel
  • SINZ Alloy Linear Rear Brake
  • AINZ Alloy Brake Lever
  • Deluxe Casing Brake Cable
  • SINZ Alloy Platform Pedals
  • KMC 1/2 x 1/8 Chain
  • SINZ Alloy 36 hole Front/Rear Hubs
  • SINZ Alloy 36 hole
  • SINZ 36 Holes 20x1.75 Rims
  • ITS Haalo's F/20x2.125 R/20x.175 Tires

Price: 279.99


INTENSE BMX PRO 20 STEEL BIKE 09
The Intense BMX Pro 20 Steel is strong bike that is quick and agile making great for any number of BMX riding styles.
  • 20" Steel Frame
  • SINZ Chromoly Race Fork 1 1/8 Steerer
  • 1-1/8" Threadles Alloy Cap Headset
  • SINZ HiTen Pro Size Handlebar
  • SINZ Alloy Stem
  • SINZ Pro Sticky Grips
  • SINZ BMX Race Saddle
  • SINZ Steel Post
  • DNP 16 tooth Freewheel
  • SINZ Tubular 3 piece 170mm Crankset
  • AM Steel Bearings Bottom Bracket Set
  • BMX Steel 43 tooth 1/8" Chainwheel
  • SINZ Alloy Linear Brake
  • AINZ Alloy Brake Lever
  • Deluxe Casing Brake Cable
  • SINZ Alloy Platform Pedals
  • KMC 1/2 x 1/8 Chain
  • SINZ Alloy 36 hole Front/Rear Hubs
  • SINZ 36 Holes 20x1.75 Rims
  • ITS Haalo's F/20x1.75 R/20x.50 Tires

Price: 249.99


INTENSE BMX FELIX BIKE '09
The Felix is a strong Dirt Jump bike that is great in the air.
  • Full CromeMoly 20.75" Frame
  • SINZ 1-1/8" Full ChromeMoly Fork
  • SINZ Sealed Intergrated 1-1/8" Headset
  • SINZ Cr Mo Handlebar
  • SINZ Alloy 1-1/8" Stem
  • SINZ Pro Sticky Grips
  • Pivotal Saddle
  • Alloy Pivotal Seatpost
  • SINZ Cassette 9T Freewheel
  • SINZ CrMO 175mm 3pc Mid BB Cranset
  • Mid Seaed Chromoly Spindle Bottom Bracket Set
  • Alloy 25T Chainwheel
  • SINZ Pro U Brake Rear Brake
  • SINZ Pro Brake Lever
  • Deluxe Casing Brake Cable
  • SINZ Alloy Pedals with removable pins
  • KMC 1/2x1/8 NP Chain
  • SINZ Pro Sealed Front Hub 36H
  • SINZ JY 36H Cassette 9T with 14mm axle, 1pc driver
  • SINZ Double wall Rims 36H R:CP
  • ITS Hustler 1.95" Tires

Price: 429.99


INTENSE BMX CLUTCH BIKE '09
The Clutch is a reliable bike that is there when you want to hit that big jump, letting you focus on the jump and not the bike.
  • Full CromeMoly 20.75" Frame
  • SINZ 1-1/8" Fork With ChromeMoly Blades
  • SINZ Sealed Intergrated 1-1/8" Headset
  • SINZ Cr Mo Handlebar
  • SINZ Alloy 1-1/8" Stem
  • SINZ Pro Sticky Grips
  • Pivotal Saddle
  • Steel Pivotal Seat Post
  • SINZ Cassette 9T Freewheel
  • SINZ CrMO 175mm 3pc Mid BB Freewheel
  • Mid Seaed Chromoly Spindle Bottom Bracket
  • Alloy 25T Chainwheel
  • SINZ Pro U Brake Rear Brake
  • SINZ Pro Brake Lever
  • Deluxe Casing Brake Cable
  • SINZ Alloy Platform Pedals
  • KMC 1/2x1/8 NP Chain
  • SINZ Pro Sealed Front Hub 36H
  • SINZ JY 36H Cassette 9T with 14mm axle, 1pc driver
  • SINZ 36H DB wall R Rims: GSW F:36H Alloy
  • ITS Hustler 1.95" Tires



Price: 429.99


INTENSE BMX DUDLEY BIKE '09
The Dudley is a strong jump bike that is killer bike whether you would rather ride urban or dirt.
  • Full CromeMoly 20.5" Frame
  • SINZ ChromeMoly Steerer 1-1/8" Fork
  • SINZ Sealed Intergrated 1-1/8" Headset
  • SINZ Hi Ten Handlebar
  • SINZ Alloy 1-1/8" Stem
  • SINZ Pro Sticky Grips
  • Pivotal Saddle
  • Steel Pivotal Seatpost
  • SINZ Cassette 9T Freewheel
  • SINZ CrMO 175mm 3pc Mid BB Crankset
  • Mid Seaed Chromoly Spindle Bottom Bracket Set
  • Alloy 25T Chainwheel
  • SINZ Pro U Brake Rear Brake
  • SINZ Pro Brake Lever
  • Deluxe Casing Brake Cable
  • SINZ Alloy Platform Pedals
  • KMC 1/2x1/8 NP Chain
  • SINZ Alloy Front Hub 36H
  • SINZ JY 36H Cassette 9T with 14mm axle, 1pc driver
  • SINZ 36H DB wall R F:36H Alloy rims
  • ITS Hustler 1.95" Tires


Price: 389.99


 

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

 

 

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Filing Cabinets on Sale at BettyMills

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