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In [[telecommunication]]s, '''8B/10B''' is a [[line code]] that maps [[8-bit]] symbols to [[10-bit]] symbols to achieve [[Direct current|DC]] balance and bounded disparity, and yet provide enough state changes to allow reasonable clock recovery. This means that there are just as many "1"s as "0"s in a string of two symbols, and that there are not too many "1"s or "0"s in a row. This is an important attribute in a signal that needs to be sent at high rates because it helps reduce "[[intersymbol interference]]". The code was described in 1983 by Al Widmer and Peter Franaszek in the [[IBM]] Journal of Research and Development. IBM was issued a patent for the scheme the following year.
<table border=1 align="right" cellpadding=2 cellspacing=0 width=250 style="margin-left:3em; margin-bottom: 2em;">
<tr><td colspan=2 style="text-align: center">[[Image:Prius2004.JPG|250px|2004 Toyota Prius]]</td></tr>
<tr><th colspan=2 style="color: white; background: darkgreen;">Toyota Prius</th></tr>
<tr><td width="40%">Manufacturer:</td><td>[[Toyota]]</td></tr>
<tr><td>Production:</td><td>[[1997]] – present</tr>
<tr><td>Class:</td><td>Economy car</tr>
<tr><td>Body Styles:</td><td>5-door [[Hatchback|hatchback]] '04–<br>4-door [[Sedan (car)|sedan]] '97–'03</tr>
<tr><td>Engines:</td><td>Gas:[[Hybrid Synergy Drive]] – 1.5L [[Straight-4|I4]] [[DOHC]] 16 valve<br>Electric:500[[volt|V]] 50 kW motor </td></tr>
<tr><td>Length:</td><td>4450 mm (175.33 in)</td></tr>
<tr><td>Width:</td><td>1725 mm (67.97 in)</td></tr>
<tr><td>Height:</td><td>1490 mm (58.71 in)</td></tr>
<tr><td>Curb weight:</td><td>1325 kg (2921 lb)</td></tr>
<tr><td>Predecessor:</td><td>none</td></tr>
<tr><td>Successor:</td><td>none</td></tr>
<tr><td>Also known as:</td><td>Toyota Hybrid</td></tr>
<tr><td>Shares components with:</td><td>none</td></tr>
<tr><td>Similar models:</td><td>[[Honda Civic Hybrid]]<br>[[Honda Insight]]<br>[[VW Jetta]] GLS [[Turbo Direct Injection|TDI]]-PD</td></tr>
<tr><td colspan=2 style="text-align: center">[[Image:OldPrius.jpg|250px|2003 Toyota Prius]]</td></tr>
<tr><td colspan=2>''This article is part of the [[automobile]] series.''</td></tr></table>
As the scheme name suggests, 8 [[bit]]s of data are transmitted as a 10-bit entity called a ''Symbol'', or ''Character''. The low 5 bits of data are encoded into a 6-bit group and the top 3 bits are encoded into a 4-bit group. These code groups are concatenated together to form the 10-bit Symbol that is transmitted on the wire. The ''Data Symbols'' are often referred to as Dxx.y where xx ranges from 0-31 and y from 0-7. Standards using the 8B/10B encoding also define ''Special Symbols'' (or ''Control Characters'') that can be sent in place of a ''Data Symbol''. They are often used to indicate end-of-frame, link idle, skip and similar link-level conditions. They are referred to as Kxx.y and have different encodings from any of the Dxx.y symbols. Because 8B/10B encoding uses 10-bit symbols to encode 8-bit words, each of the 256 possible 8-bit words can be encoded in two different ways, one the bit-wise inverse of the other. Using these alternative encodings, the scheme is able to affect long-term DC-balance in the serial data stream, allowing links to be capacitively coupled.
The '''Toyota Prius''' is one of the world's first commercially mass-produced [[hybrid electric vehicle|hybrid automobile]]s. Manufactured by [[Toyota]], the Prius first went on sale in [[Japan]] in [[1997]]. The car was introduced to the worldwide market in [[2000]] and almost 160,000 units had been produced for sale in Japan, [[Europe]], and [[North America]] as of the end of 2003. In [[Latin]], ''prius'' means "ahead". The Prius (2000–2003 model years) is certified as a [[Super Ultra Low Emission Vehicle]] (SULEV) by the [[California Air Resources Board]] (CARB). The 2004 model is certified as an [[PZEV|Advanced Technology Partial Zero Emission Vehicle]] (AT-PZEV), which means it earns PZEV credits, as opposed to it being a Zero Emissions vehicle part of the time.
The encoding is normally done entirely in hardware based on lookup tables. Upper levels of the software stack should be unaware that this encoding is being used.
The car was voted [[2005]] [[European Car of the Year]], after the fuel-sipping [[sedan]] picked up the corresponding ''[[Motor Trend]]'' [[Car of the Year]] title for 2004. The Prius won the ''[[North American Car of the Year]]'' award for 2004 and was nominated in 2001.
Among the areas in which 8B/10B encoding finds application are [[Fibre Channel]], [[Gigabit Ethernet]], [[InfiniBand]], [[XAUI]], and audio storage devices such as the [[Digital Audio Tape]] and [[Digital Compact Cassette]] (DCC). The related [[Eight-to-Fourteen Modulation]] is used in the [[Compact Disc]] standard. The encoding scheme used in [[10 Gigabit Ethernet]]'s 10GBASE-R [[Physical Media Dependent]] (PMD) interfaces, 64B/66B, while similarly created with consideration of DC balance, maximum run length, transition density, electromagnetic emissions, and the like, is considerably different in design.
==How it works==
The Prius has been called a true hybrid vehicle, designed from the bottom up. Toyota's goal for the Prius is to reduce the amount of emissions it produces and to be as energy-efficient as possible. They used several methods to try to achieve this goal, including:
#More efficient use of the [[internal combustion engine]] (ICE) and [[electric motor]]s, reducing gasoline consumption. The Prius uses the more efficient [[Atkinson Cycle]] engine instead of the more common [[Four-stroke cycle|Otto Cycle]];
#Two [[electric motor]]/[[generator]]s, providing 67 hp (50 kW) @ 1200–1540 rpm and 295 ft·lbf (111 Nm) torque from 0–1200 rpm, which significantly contribute to performance & economy.
#50 kW [[IGBT]] [[inverter]] controlled by a 32 bit [[microprocessor]], which efficiently converts power between the batteries and the motor/generators.
#Lower [[Drag coefficient|coefficient of drag]] at 0.29 (0.26 for 2004 model), reducing air resistance especially at higher speeds;
#Lower rolling-resistance tires, reducing road [[friction]];
#[[Regenerative braking]], a process for recovering [[kinetic energy]] when braking or traveling down a slope and storing it as [[electrical energy]] in the traction battery for later use while reducing wear and tear on the brake pads;
#Sealed 168 cell [[nickel metal hydride]] (NiMH) [[rechargeable battery|battery]] providing 201.6 volts;
#[[Continuously variable transmission]] -- the Prius does not use a typical CVT; Toyota calls it the [http://home.earthlink.net/~graham1/MyToyotaPrius/Understanding/PowerSplitDevice.htm Power Split Device]. The electric motors and gas engine are connected to a [[planetary gear]] set which is always engaged, and there is no shifting.
#Flexible resin gas tank, reducing the amount of [[hydrocarbon]] emissions in the form of escaped gasoline vapor.
Touted advantages of the Prius over previous energy-efficient designs include never needing to be plugged in, as all power is ultimately delivered from the gasoline engine. This means it drives like a traditional ICE automobile, with the onboard computer taking care of shifting power to and from the engine and motors, and automatically determining when to charge the battery, as well as the most efficient use of the engine or the electric motors (or both) based on driving conditions. This also means that one can not choose to use electricity from other sources to power this vehicle; some consider this to be serious disadvantage.
The engine is permitted to shut down once it has warmed up and the [[catalytic converter]] in the exhaust system has reached operating temperature. Once this occurs, the Prius can be driven on electric power only; this is sometimes referred to as "stealth mode" due to the lack of engine noise. This further reduces gasoline consumption and wear and tear on the engine. When driving conditions demand additional power from the engine, it is designed to start up automatically.
Frequent starting up and shutting down of the engine should not cause additional wear and tear nor emission problems, as in conventional automobiles, because the drive motors have enough power to quickly and smoothly spin the engine to optimal [[rpm]] (around 1,000) before the engine actually begins to "fire up". This avoids wear when the engine is "running" (with fuel and spark) at very low RPM, as happens in most vehicles.
The Prius gets better fuel efficiency in the city because the batteries get used more, whereas on the highway, the engine is used in order to recharge the batteries, and the wind resistance is higher.
==2004 Prius==
[[Image:Prius2004HSD.JPG|thumbnail|right|Hybrid Synergy Drive]]
[[Image:ToyotaOpenHSD.jpg|thumbnail|right|HSD high voltage unit]]
[[Image:PriusPowerSteering.jpg|thumbnail|right|Electric [[power steering]]]]
[[Image:PriusBatteryModule.jpg|thumbnail|right|A battery module used on the Prius]]
The Prius 2004 model year is a complete redesign of the previous generations of Prius. The first generation (1997–2003) could not run its air conditioning unless the motor was running. In contrast, the 2004 model uses an all electric [[heat pump]] for heating and cooling. This allows more extensive use of the "stealth mode" (operation on electric motor only).
The new [[drag coefficient]] of 0.26 is the lowest in the industry.
The new (third generation) [[Hybrid Synergy Drive]] (HSD) replaces the earlier [[Toyota Hybrid System]] (THS) technology.
The 2004 Prius is a midsize car with more room than the previous compact and is a five door model (4 doors plus a rear hatch). In general the car is conveniently narrow on the outside, rather flat sided, and relatively tall (several inches taller than a [[Toyota Camry|Camry]]). The profile is much more continuous, with a short sloping nose transitioning to a highly sloped windshield and an arcing roofline ending in a cut-off [[Kammback]]. The additional height allows a more erect seating position and a higher eye point, giving a better view of the road to the driver. There is also a surprising amount of rear seat leg room, resembling that available in a much larger vehicle. Fold down rear seats with a 60/40 split make for easy carriage of most parcels.
With a smaller and lower voltage NiMH battery and an inverter to step the voltage up to 500V, the new model is more powerful (2 seconds faster in 0 to 96 km/h acceleration) and is 15% more [[fuel efficiency|fuel efficient]] than the previous generation Prius, with 60 mpg (4.7 L/100km) city and 51 mpg (5.5 L/100km) highway (according to the [[EPA]]). As the EPA city test is more consistent with downtown Manhattan than it is with most suburban driving, your mileage may vary. When driven appropriately, commuting and mixed suburban drivers are reporting realistic mileages of 45 to 50 mpg (6.3 to 5.7 L/100km). See also
[http://www.usatoday.com/money/autos/2004-02-03-hybridmileage_x.htm]
The display shows mileage bars for each five minute segment of driving and this can encourage economical driving. The display also indicates instantaneous milage, which is useful for detecting when the vehicle has switched from electric-only to electric plus ICE. At this time it can usually be advantageous to accelerate rather than lug the vehicle, in an attempt to get to a more favorable ___location or speed range for electric-only mode.
The vehicle is classified as a [[SULEV]] (Super Ultra Low Emissions Vehicle), 90% cleaner than conventional gasoline-only automobiles. It comes with an Advanced Technology Partial Zero Emission Vehicle (AT-[[PZEV]]) certification by [[CARB]] (California Air Resources Board).
As an interesting side note, a $2,200 option package offered in Japan for the 2004 model gives it the ability to perform parallel parking by the on-board computer. Eighty percent of the Prius buyers in Japan have chosen this option. The system is not intelligent, though, so it is very limited. [http://www.cnn.com/2004/TECH/ptech/01/15/car.selfpark.ap/index.html]
When the vehicle is started it will operate for seven seconds before starting the engine. This can allow you to remove the vehicle from a garage before starting and so reduce the pollution in the house. Unfortunately it is much too quick to start the engine in most cases, as in some locations a complete downslope trip could be made without starting the ICE engine - actually putting energy into the battery. The Asian and European version of this vehicle provide a button labelled "EV" that maintains stealth mode after startup under most low load conditions. The US model has a nonfunctional blank button, although it is supported internally by the computer. While some have speculated that it was not been included in the interest of retaining the warranted battery life (100,000 miles in US 150,000 in California and several other states), engineers who note that EV mode is automatically overridden when the battery is only partially depleted have disputed that. In addition to information at online discussion groups, the [http://www.priusplus.org PRIUS+ Project] offers instructions for do-it-yourselfers who wish to enable the button, and aftermarket components provider [http://www.coastaletech.com/ Coastal Electronic Technologies] offers a kit.
Evolving from the button project, [http://www.calcars.org The California Cars Initiative] converted a Prius in 2004, adding larger batteries, and a private company [http://www.edrivesystems.com/ EDrive Systems] announced plans to sell conversion kits in 2006. CalCars initiated efforts to promote fleet purchases of plug-in hybrids to be built by automakers, and documented the emissions benefits of plug-in hybrids not only on California's clean power grid but also on the national (50% coal-fueled) power grid.
A driving trick: Often you will pull up at a stop light that has just changed. In some suburban areas this may entail a wait of several minutes, as the lights cycle through various simultaneous or sequential left turns, cross traffic, pedestrians, etc. If the gasoline engine is running when you approached the stop it will take the better part of a minute before the computer recognizes the situation and shuts off the engine. There is a trick to getting the engine to shut off promptly. If you approached the stop in '''B''' (engine assist braking), you may then when stopped with the brake on, command '''N''' (neutral), then '''D''' (drive) - the engine will stop immediately - at least in 2004 US versions.
Passengers of the Prius can use their [[Bluetooth]]-enabled [[cellphone]] via the car's audio system without taking the phone out of their pocket. It is the first car released with this feature.
==Versions==
The first Prius model, NHW10, was sold only in Japan though [[grey import|personal imports]] have been made to Europe and Australia. Subsequent versions have seen wider sales, increased power and reduced battery weight.<br>
{| border="1" cellpadding="2" cellspacing="0"
|-
|rowspan="2" colspan="2"|'''Feature'''||colspan="3" align="center"|'''Model Code'''
|-
|align="center"|'''NHW10'''||align="center"|'''NHW11'''||align="center"|'''NHW20'''
|-
|Body Style|| ||align="center"|4 Door<br>Sedan||align="center"|4 Door<br>Sedan||align="center"|5 Door<br>Hatchback||
|-
|First Sales|| ||align="right"|1997||align="right"|2000||align="right"|2003
|-
|rowspan="7"|Battery
|Modules||align="right"|40||align="right"|38||align="right"|28
|-
|Cells per module||align="right"|6||align="right"|6||align="right"|6
|-
|Total cells||align="right"|240||align="right"|228||align="right"|128
|-
|Volts per cell||align="right"|1.2||align="right"|1.2||align="right"|1.2
|-
|Total volts||align="right"|288||align="right"|273.6||align="right"|201.6
|-
|Capacity Amp hours||align="right"|6.5||align="right"|6.5||align="right"|6.6
|-
|Weight kg||align="right"|57||align="right"|50||align="right"|45
|-
|rowspan="2"|Petrol<br> Engine||Power kW||align="right"|43||align="right"|52||align="right"|57
|-
|Max rpm||align="right"|4000||align="right"|4500||align="right"|5000
|-
|Electric<br>Motor||Power kW||align="right"|30||align="right"|33||align="right"|50
|}
==Notable facts==
* 2005 European Car of the Year (Toyota Prius 2nd generation with 406 points, ahead of Citroen C4 with 267 points and Ford Focus II with 228) [http://www.di-ve.com/dive/portal/portal.jhtml?id=161929&pid=null]
* ''[[Motor Trend]]'' [[Motor Trend Car of the Year|Car of the Year]] 2004 (January 2004 issue)
* ''[[Car and Driver]]'' magazine's [[Car and Driver Ten Best|Ten Best list]] for 2004.
*Drivers of the Toyota Prius, or other Hybrid-Engine automobiles are allowed to drive by themselves in Carpool (High Occupancy Vehicle) lanes in some US states such as Virginia, California (pending) and Florida (requires $5 per year decal).
* Los Angeles and San Jose, California allow free parking at meters for hybrid vehicles, including the Prius.
*Due to the success of both the engineering and sales of the Prius, in 2005, Toyota plans to release a hybrid V-6 engine for the Lexus RX400h, as well as a hybrid engine version of the Highlander.
*Toyota is also actively developing a hydrogen-fuel-cell engine. They have already successfully developed a RAV4 that can achieve 900 miles (1450 km) on one tank of [[hydrogen]].
*The fuel tank holds 11.9 gallons (45 L), although the internal bladder in American models limits the fill, giving a range of up to 600 miles (1,000 km).
*In [[August 2004]], Toyota began a Special Service Campaign (SSC 40G), affecting most previous generation Prius cars manufactured between 2001 and mid-2003. This repair involves re-sealing terminals on the high-voltage battery to avoid minor [[electrolyte]] leakage. Repairs will be performed free of charge on affected automobiles.
*Starting with the 2004 model, Toyota is now producing the Prius on a standard mass production assembly line, resulting in one being produced every minute instead of one every 8 to 10 minutes. The use of a standard assembly line has dropped the manufacturing cost significantly, allowing Toyota to deliver a substantially upgraded model, which in turn has generated publicity and popularity. The limiting factor in Prius (and Lexus RX400h) production now appears to be third party component availability, particularly batteries.
*The battery pack of the 2004 Prius is guaranteed for 100,000 miles (160,000 km) or 8 years, although Toyota has stated that they expect it to last 15 years. The warranty is extended to 150,000 miles (240,000 km) or 10 years for Prius in California and several other states that adopted the [[California Air Resources Board|Californian emission control standards]].
*In May 2005, Finnish anti-virus firm [[F-Secure]] Corp. has tested a Prius for [[Bluetooth]] vulnerabilities in the on-board mobile telephony and computer systems and [http://www.f-secure.com/weblog/#00000553 found the car has performed admirably.]
*On June 1, 2005, the National Highway Traffic Safety Administration of the US started an investigation on the 33 reported cases of engine stalling when the Prius travels at highway speed. The cars were still operatable under battery power with substantial loss of power when the internal combustion engine failed to run. Toyota believes it was due to a computer programming error that was fixed in a recall (SSC-40D) issued back in September, 2004. The investigation needs to verify if all the reported cases occured to the cars that didn't receive the software fix. Some supporters argued that 33 cases among 75000+ cars sold was not an alarming figure. Besides, the Prius is safer than any other car with a failed engine, the Prius can still run with its electric motor until it can stop at a safe ___location.
==Sales==
*In [[January 2005]], the Prius became available in [[South Africa]].
*Toyota will increase production by an additional 50% for [[2005]], now producing 15,000 cars per month, and will import 100,000 into the [[United States]] for that model year.
*In [[June 2004]], the [[Wall Street Journal]] reported that the backlog for 2004 Prius has reached 22,000 in the US.
*[[As of 2004|As of April 2004]], the expected delivery time for Prius in the [[Netherlands]] is one year.
*[[As of 2004|As of March 2004]], the waiting list at a [[Sonoma County, California]] dealership was over 100 people long.
*[[As of 2004|As of February 16, 2004]], Toyota USA is not taking new internet orders for the 2004 Prius.
*[[As of 2003|As of December 14, 2003]], the waiting time in [[Dallas, Texas]], USA, was 6 months.
==Other hybrid-engine vehicles==
*[[Honda Civic Hybrid]], another car which works similarly, but never runs exclusively on electricity.
*[[Honda Insight]], a 2-seat, [[manual transmission]] hybrid car which the EPA claims gets 60 miles per US gallon in the city, 66 mpg highway (3.92 litres per 100 km city, 3.56 L/100km highway ), also cannot be driven without the [[gasoline engine]].
*2005 [[Honda Accord Hybrid]], a hybrid based on the popular Accord Sedan; cannot be driven without the [[gasoline engine]].
*[[Ford Motor Company]] has released the 2005 [[Ford Escape Hybrid]] SUV. Toyota and Ford entered into a licensing agreement in March 2004 allowing Ford to use 20 patents from Toyota related to hybrid technology, although Ford's engine was independently designed and built. In exchange for the hybrid licences, Ford licensed patents involving their European diesel engines to Toyota.
*The 2007 [[Nissan Altima]] has been announced. Nissan are not only licensing but also sourcing hybrid engine parts from Toyota for this vehicle.
==See also==
*[[Toyota Motor Corporation]]
*[[Hybrid car]]
*[[Plug-in hybrid electric vehicle]]
==External links==
*[http://domino.research.ibm.com/tchjr/journalindex.nsf/0/b4e28be4a69a153585256bfa0067f59a?OpenDocument Original paper by Franaszek and Widmer].
*[http://www.prius.com Offical Worldwide Prius Site]
*[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=/netahtml/search-bool.html&r=1&f=G&l=50&co1=AND&d=ptxt&s1=4486739.WKU.&OS=PN/4486739&RS=PN/4486739 US Patent 4,486,739], the relevant document at the US Patent and Trademark Office's site.
*[http://www.greenhybrid.com GreenHybrid.com: The interactive hybrid electric vehicle resource]
*[http://news.bbc.co.uk/2/hi/business/4015831.stm BBC: Prius not just a car - it is a phenomenon]
*[http://www.toyota.com/prius Official USA Prius web site]
*[http://www.toyota.co.jp/en/tech/environment/hsd/pdf/a_guide_to_hsd.pdf Toyota's paper on how the 2004 Prius is different from earlier models (in PDF)]
*[http://home.earthlink.net/~graham1/Prius/Prius.htm discussion on Prius at Graham's web site]
*[http://john1701a.com/ Information, tips, and photos about Prius at John's web site]
*[http://groups.yahoo.com/search?query=Prius Yahoo! Groups about the Prius]
*[http://www.arb.ca.gov California Air Resources Board]
*[http://www.findarticles.com/cf_dls/m3012/10_183/109505549/p1/article.jhtml Automotive Industries article]
*[http://www.priuschat.com/forums/portal.php PriusChat.com] — forums
*[http://home.earthlink.net/~jkash1 Mr. Kash's Prius Page] — Many links to Prius news stories and reviews.
*[http://www.calcars.org/priusplus.html PRIUS+ page at CalCars.org] - Nonprofit group is converting '04-'05 Priuses into plug-in hybrids
*[http://www.di-ve.com/dive/portal/portal.jhtml?id=161929&pid=null Toyota Prius is 2005 European Car of the Year]
*[http://groups.yahoo.com/group/prius_sa/ South African Toyota Prius Group]
[[Category:ToyotaComputer vehicles|Priusand telecommunication standards]]
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