Toyota Prius
Overview
Manufacturer	Toyota Motor Corporation
Also called	Toyota Hybrid
Production	1997–present
Assembly	Toyota City, Japan
Body and chassis
Class	Hybrid car
Layout	FF layout

NHW20
Overview
Production	2004–present
Body and chassis
Class	Midsize car
Body style	5-door hatchback
Powertrain
Engine	Hybrid Synergy Drive Gasoline: 1.5 L DOHC I4 VVT-i 57 kW (76 hp) @ 5000 rpm 115 N·m (85 ft·lbf) @ 4200 rpm Electric: 500 V 50 kW (67 hp) @ 1200 rpm 400 N·m (295 ft·lbf) @ 0 rpm AT-PZEV Net power: 110 hp (82 kW)
Transmission	CVT
Dimensions
Wheelbase	2700 mm (106.3 in)
Length	4450 mm (175.33 in)
Width	1725 mm (67.97 in)
Height	1490 mm (58.71 in)
Curb weight	1325 kg (2921 lb)

NHW11
Overview
Production	2000–2003
Body and chassis
Class	Compact car
Body style	4-door sedan
Powertrain
Engine	Toyota Hybrid System Gasoline: 1.5 L DOHC I4 VVT-i 13.0:1 compression 52 kW (70 hp) @ 4500 rpm 110 N·m (82 ft·lbf) @ 4200 rpm Electric: 273.6 V motor 33 kW (44 hp) @ 1040 rpm 350 N·m (258 ft·lbf) @ 0 rpm SULEV
Transmission	1-speed CVT
Dimensions
Wheelbase	2550 mm (100.4 in)
Length	4308 mm (169.6 in)
Width	1694 mm (66.7 in)
Height	1463 mm (57.6 in)
Curb weight	1254.2 kg (2765 lb)

NHW10
Overview
Production	1997–2001
Body and chassis
Class	Compact car
Body style	4-door sedan
Powertrain
Engine	Toyota Hybrid System Gasoline: 1.5 L DOHC I4 13.5:1 compression 43 kW (58 hp) @ 4000 rpm 102 N·m (75 ft·lbf) @ 4000 rpm Electric: 288 V motor 30 kW (40 hp) @ 940 rpm 305 N·m (225 ft·lbf) @ 0 rpm
Dimensions
Length	4275 mm (168.3 in)
Width	1694 mm (66.7 in)
Height	1491 mm (58.7 in)

The Toyota Prius is one of the first mass-produced and marketed hybrid electric vehicles.

The 2000 model Prius slotted between the Echo and Corolla in the company's North American lineup, and is certified as a Super Ultra Low Emission Vehicle (SULEV) by the California Air Resources Board (CARB). With the 2004 model, the Prius was redesigned as a midsize hatchback slotting between the Corolla and Camry, and is certified as an Advanced Technology Partial zero-emissions vehicle (AT-PZEV).

The Prius first went on sale in Japan in 1997, and worldwide in 2001. By the end of 2003, nearly 160,000 units had been produced for sale in Japan, Europe, and North America. The Prius has won numerous awards including Car of the Year awards in Europe, Japan and North America.

The Prius is a series-parallel configuration hybrid, a vehicle that can run on just the engine, just the batteries, or a combination of both. Toyota's design goals are to reduce the amount of pollution and to maximize fuel efficiency. To do this, it uses a gasoline/electric hybrid powertrain, incorporating large batteries that are charged by the gas (petrol) engine directly or by regenerative braking (cannot be plugged in as built). Either the engine or the battery (or both) can power the vehicle, depending on conditions. This gives it the acceleration and power of a standard car having a much larger gasoline-burning engine. Specifically, the Prius incorporates:

1. More efficient use of the internal combustion engine (ICE), reducing gasoline/petrol consumption. The 1NZ-FXE engine uses the more efficient Atkinson cycle instead of the more common Otto cycle;
2. Two electric motor/generators, MG1 and MG2 are in the transaxle. The MG2 provides 50 kW (67 hp) @ 1,200 to 1,540 rpm and 400 N·m (295 ft·lbf) torque from 0 to 1,200 rpm, which significantly contributes to performance and economy. The MG1, with rpm from -10,000 to +10,000 rpm, provides the engine starter and counter torque for the electronic Continuously Variable Transmission;
3. 50 kW IGBT inverter controlled by a 32-bit microprocessor, which efficiently converts power between the batteries and the motor/generators.
4. Lower coefficient of drag at 0.26 (0.29 for 2000 model), with a Kammback design reducing air resistance, especially at higher speeds;
5. Lower rolling-resistance tires on the 2000 model, reducing road friction;
6. Regenerative braking, a process for recovering kinetic energy when braking or travelling down a slope and storing it as chemical potential energy in the traction battery for later use while reducing wear and tear on the brake pads;
7. Sealed 168-cell nickel metal hydride (NiMH) battery providing 201.6 volts; supplied by Panasonic EV Energy Co
8. Continuously variable transmission — the Prius uses a computer-managed (rather than a mechanical) CVT; Toyota calls it the Power Split Device^[1]. The electric motors and gasoline engine are connected to a planetary gear set which is always engaged, and there is no shifting.
9. Flexible resin gasoline tank, reducing the amount of hydrocarbon emissions in the form of escaped gasoline vapour; (US model only)
10. Vacuum flask coolant storage system that stores hot engine coolant when the vehicle is powered off, then reuses it to reduce warm-up time. (US model only)
11. EV mode (Europe and Asian markets only, aftermarket option in the U.S.) allows the driver to select electric-only mode in low-power conditions. The vehicle can only be driven a couple of kilometers (depending on conditions) on battery power alone before the gas engine is needed.
12. Weight reduction — for example the hatch and hood/bonnet are made of aluminium instead of steel.

One reason that the Prius gets such good gasoline mileage is that the ICE is smaller than in most cars this size. The ICE usually shuts off at stop lights and when backing up and descending long hills. The Prius performance remains very good because the battery/electric motor booster automatically provides more than enough extra power for acceleration and hill climbing. This means it drives like a traditional ICE automobile, with the on-board 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 cannot use electricity from external sources. Advocates of 'plug-in' hybrids consider this to be a missed opportunity. The Prius also uses its electric motor to recharge the battery during braking, with kinetic energy normally wasted as heat being recaptured. This also significantly reduces brake wear.

The engine can shut down once it has warmed up and the catalytic converter in the exhaust system has reached operating temperature. The Prius can then operate solely on electric power under low energy loads. This is sometimes referred to as "stealth mode" due to the lack of engine noise. While this further reduces gasoline consumption and engine wear, the Prius is so quiet it can be hazardous to blind pedestrians and others accustomed to engine noise to warn of a nearby vehicle. When driving conditions demand additional power, the engine starts up automatically.

The on-board computer ensures that the engine runs under the most efficient conditions. Typically, a petrol/gasoline engine runs inefficiently at half-throttle, creating a choking condition. This effect, called pumping loss, is a major reason for the inefficiency of gasoline engines compared to diesels. The Prius minimizes pumping loss by running the gasoline engine at a high torque range with the throttle fully open. Drive-by-wire throttle control technology and Toyota's Hybrid Synergy Drive (a torque combiner, electric drive, and computer control) are essential to this engine control.

In addition to the immediate benefit of reducing fuel consumption and emissions, stopping the combustion engine also improves the performance of the catalytic converter. In a non-hybrid vehicle the exhaust gases from an idling engine tend to cool the catalysts below their optimal temperature.

The frequent starting and stopping of the engine does not cause additional wear and tear or emission problems because the drive motors have enough power to quickly spin the engine to optimal rpm (around 1,000) before the engine fires up. This avoids the wear that would occur if the engine were to run (with fuel and spark) at very low rpm.

For any car, aerodynamic losses due to drag are much greater on the highway than in low speed city driving. A non-hybrid car nonetheless gets worse mileage in city driving because its engine is far less efficient at low power, such as when stopped in traffic, and because it must frequently dump its kinetic energy into the brakes during stop-and-go driving. The Prius gets better fuel efficiency in city dynamometer cycles because the engine can shut down instead of running at low power, and run solely off the battery at low speeds and when stopped (including the cabin air heating/cooling system and the power steering). Also, the car's kinetic energy is captured when braking and stored in the battery. According to the revised EPA tests^[2], the Prius gets Template:Mpg in the city dynamometer tests, compared with Template:Mpg on the highway, and Natural Resources Canada estimates Template:Mpg in the city and Template:Mpg on the highway. (Owing to peculiarities of these tests, few drivers obtain these mileage values in typical suburban circumstances, but "real world" performance with careful driving can come close. Typical real-world drivers get about Template:Mpg - Template:Mpg, hypermilers can get up Template:Mpg. This means the greatest advantages of a hybrid are mainly in city driving, though factors including driving style, air conditioning use, and short trips may offset some of this advantage. The hybrid has less of an advantage in higher speed open road driving typical of intercity driving, yet obtains improved mileage under these circumstances since it can use a smaller and more efficient engine than would otherwise be required (because the battery and electric motor can provide the extra peak power needed for passing and limited hill climbing).

The first Prius model, NHW10, was sold only in Japan, though personal imports have been made to the British Isles, Australia, and New Zealand. Subsequent versions have seen wider sales, increased power and reduced battery weight.

Production of the Prius for the China market began in December 2005 by Sichuan FAW Toyota Motor, a joint venture with First Automobile Works.

The first Prius sold in the U.S. was a compact sedan with a distinctive front hood (bonnet). Sold in relatively small numbers, it nevertheless gained wide attention and proved the market existed for a sensible hybrid vehicle as a family car.

The Prius 2004 model was a complete redesign of the previous generations of Prius. The new model is larger inside and out (now a mid-size vehicle), gets even better gas mileage and is a hatchback. It is based on the new (second generation) Hybrid Synergy Drive (HSD or also known as THSII), replacing the earlier Toyota Hybrid System (THS) technology. The first generation (1997 to 2003) used the engine to run the air conditioning compressor. While idling, the engine would need to start every minute or so if the air conditioning was running. In contrast, the 2004 model introduced an all-electric compressor for cooling. This not only allowed the use of air conditioning without the engine starting from time to time when the car was completely still, it also allowed more extensive use of the "stealth mode" (operation on electric motor only).

Its drag coefficient of 0.26 was then the second-lowest in the industry, after the Honda Insight at 0.25.

Regenerative braking was greatly improved, relying so little upon the friction-type brakes (except for panic stops) that some Toyota technicians quipped that the original brake pads might well last for the life of the car.

The 2004 Prius emerged as a midsize car with more room than the previous compact, redesigned as a "five-door" model (four doors plus a rear hatch). In general, the car remained conveniently narrow on the outside, rather flat-sided, and relatively tall (several inches taller than a Camry). The profile was more continuous, with a short sloping nose transitioning to a highly sloped windscreen and an arcing roofline ending in a cut-off Kammback. The additional height allowed a more erect seating position and a higher eye point, giving a better view of the road to the driver. There was also a surprising amount of additional rear-seat leg room, resembling that available in a much larger vehicle. Fold down rear seats with a 60/40 split made for easy carriage of most parcels. It retains a tight turning radius of 17 feet (34 feet or 10.4 meters in diameter), which when combined with a short hood is particularly useful in urban environments.

With a smaller and lower voltage NiMH battery and a boost converter to step the voltage up to 500 V, the 2004 model was more powerful (2 seconds faster in 0 to 96 km/h acceleration) and is 15% more fuel efficient than the previous generation Prius^{[citation needed]}. Except in short trips or extreme cold, typical commuting and mixed suburban drivers are reporting fuel consumption of 45 to 50 miles per US gallon (19-21 km/L). ^[3] Models have a 0-60 mph acceleration time of 10.1 seconds and a top speed of 105 mph (169 km/h) when using both electric and internal combustion motors simultaneously. When exclusively using its electric motor, the Prius has a 42 mph (68 km/h) top speed.

The multi-function-display (MFD) shows fuel consumption bars for each five minute segment of driving and this can encourage economical driving. The display also indicates instantaneous fuel consumption, 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 quickly rather than lug the vehicle, in an attempt to get to a more favorable location or speed range for electric-only mode.

An option called the Smart Key System (SKS) eliminates the traditional ignition key. The "smart key," which resembles a conventional keyless entry remote, has buttons to remotely lock and unlock the door, as well as trigger the alarm system. It is not necessary to use any of the buttons to utilize the SKS. Approaching to within one meter of the car while in possession of the key (even inside a pocket or purse) causes the interior dome lights to fade in (if the switches are at the DOOR position). When the person with the key in their possession touches the inside of either of the front door handles, or the rear hatchback door handle, that door (or more) is immediately unlocked and can be opened. There are three settings in which the Smart Key System (SKS) can operate: driver's door unlocking mode, single door unlocking mode, and all doors unlocking mode. Once inside, the car may be started by pushing the "POWER" button while depressing the brake pedal, with the fob still safely tucked away inside your pocket or purse. To stop the car, push the "POWER" button again. Once parked, the car can be locked by a pushing a black button on the exterior door handle. The SKS will detect keys left inside the vehicle when powered-off, and will not allow the vehicle to be locked in this situation.

On cars which are not equipped with SKS, the driver uses the lock/unlock buttons on the fob, and puts the remote fob into a slot in the dash to allow the car to start.

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 the California Air Resources Board (CARB).

As an interesting side note, an option package offered in Japan and Europe gives the Prius the ability to perform parallel and reverse parking assisted by the on-board computer — the first time such a capability has been offered on a production vehicle. Eighty percent of the Prius buyers in Japan have chosen this option. The system is not intelligent though, particularly lacking machine vision which would allow avoidance of obstructions or pedestrians, so it is very limited. ^[4]

The Prius also has an optional Bluetooth hands free kit for cellphones, which uses one of the stereo's speakers in the driver door, and a microphone near the rear-view mirror. The steering wheel has a dedicated button for answering and hanging up the phone while driving. The hands free system usually comes in the highest or next-to-highest packages from the dealership. Most, but not all Bluetooth phones are 100% compatible with the Prius. Nearly all phones have the minimum functionality of using the car as a headset, but some phones also allow some or all of the following actions:

• Copy phone numbers to the Prius' (small) internal phone book (some allow them to be sent all at once).
• Display cell tower signal strength on any cellphone related screen.
• Cell phone ring tone heard through the car audio system.
• Voice dialing through car audio system.

The 2006 Prius introduced some minor cosmetic changes, along with optional features such as advanced airbags, a rear-view camera, an upgraded audio system (including a line-in port), an updated Navigation DVD with new user interface, and a higher-resolution liquid crystal display.

The 2007 Prius carries over the newer features from 2006 (also slightly higher price), while making the advanced and side-curtain airbags standard on all models. Also available is a Touring Edition that includes an elongated larger rear spoiler as well as larger, sharper-pointed 7-spoke 16" alloy wheels with plastic hub cap cover to protect it from scratches when parking against the curb. In addition, the Touring Edition also comes with a firmer European tuned suspension, standard high-intensity-discharge (HID) headlights and integrated (non-HID) fog lights.

• 2007 Toyota Prius 4-Door Liftback (MSRP $22,175)
• 2007 Toyota Prius Touring (MSRP $23,070).

The third generation Hybrid Synergy Drive from Toyota will decrease costs and weight^[5]. It is expected to use NIMH batteries initially and then switch later to lithium-ion batteries for greater energy density, resulting in better performance and less weight, although safety issues are a concern^[6][7] . Toyota CEO Katsuaki Watanabe confirmed this in an interview with BusinessWeek on February 16, 2007. "We are now aiming at reducing, by half, both size and cost of the third-generation hybrid system," said Watanabe.

It has been mentioned that a future Prius will receive an upgrade of the petrol (gasoline) engine from 1.5 litres to 1.8 litres. A plug-in hybrid version of the Prius will allow for greater gas mileage with a bigger engine.^{[8] [9]} It has also been suggested that a range of different sized models are planned, (referred to by engineers as the Prius A, B and C), rather than a single model ^[10] . The first of these new models is expected in 2009 ^{[11] [12]} . Toyota spokesman said that future Prius research "...is broad-reaching and being carried out from various angles." ^[13]

NHTSA crash testing of the 2004 Prius yielded a five star driver and four star passenger rating in the frontal collision test (out of five stars). Side crash results were four out of five stars for both front and rear seats. The car scored four out of five stars in rollover testing. ^[14]

In 2004, EuroNCAP tested the Prius. It earned these ratings:

• Adult Occupant Rating- Template:Rating-5
• Child Occupant Rating- Template:Rating-5
• Pedestrian Rating- Template:Rating-4

• 1997–98 Car of the Year Japan^[15]
• 2003 Scientific American names Toyota Motor Corporation as "Business Leader of the Year" ("Scientific American 50"; December, 2003) for its singular accomplishment in the commercialization of affordable hybrid cars.
• Motor Trend Car of the Year 2004 (January 2004 issue)
• Car and Driver magazine's Ten Best list for 2004.
• North American Car of the Year award for 2004. Nominated in 2001.
• International Engine of the Year for 2004.
• "Best Engineered Vehicle for 2004" by SAE's Automotive Engineering International magazine.^[16]
• 2005 European Car of the Year (406 points, ahead of Citroën C4 with 267 points and Ford Focus II with 228).^[17]
• 2006 EnerGuide Award (Midsize)^[18]
• 2006 Intellichoice Best Overall Value of the Year, Midsize ^[19]
• 2007 Intellichoice Best in Class Winner :Best Retained Value, Lowest Fuel, Lowest Operating Costs, Lowest Ownership Costs^[20]

• The NHW20 Prius fuel tank holds 45 litres (11.9 US gal), although the internal bladder in American models limits the fill (particularly in colder weather), giving a range of up to 1,000 km (600 miles) under good conditions. The fuel tank capacity for a European NHW11 without the bladder is 50 litres.
• The battery pack of the 2004 Prius is warranteed for 160,000 km (100,000 miles) or 8 years, although Toyota has stated that they expect it to last 15 years. The warranty is extended to 240,000 km (150,000 miles) or 10 years for Prius in California and several other states that adopted the Californian emission control standards. ^{[citation needed]}

The word prius is sometimes said to be a Latin word meaning "to go before" ^[21], and a Toyota spokesman did in fact say in 2004, "Prius is a Latin word meaning 'to go before'" and "Toyota chose this name because the Prius vehicle is the predecessor of cars to come." ^[22]

In fact prius is a not a verb but a Latin comparative adjective or adverb, the neuter nominative singular form of the adjective whose corresponding masculine and feminine nominative singular forms are prior, ^[23] (see also Latin declension#Irregular adverbs and their comparative and superlative forms) with meanings "ahead, in front, leading; previous, earlier, preceding, prior; former; basic;" ^[24].

Many enthusiasts enjoy using Prii as the plural, which would be correct if prius were a regular second declension Latin noun. The actual Latin plural of the adjective is priora. (^[22] is slightly in error here) All of these forms are nominative case and there are several other forms for the other cases. As for the plural of Prius in English, Toyota has said that it is simply Prius ^[25], and also that owners are welcome to use whatever they like. ^[26]

• In July 2006 Toyota issued a recall totaling 34,700 units covering early model Prius and Echo cars (26,200 Echo and 8,500 Prius). This recall was not related to hybrid components of the car. The connector for the crankshaft position sensor may become disconnected.^[27]
• In May 2006, Toyota announced the recall of up to 170,856 Prius vehicles because of a crack which can develop in the steering shaft if the Prius is frequently steered at full lock, or if the front tires strike the curb. The fault can affect Priuses made in 2004 through to November 2005.^[28][29]
• 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 operable under battery power for a short distance 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 valid reported cases occurred to cars that did not receive the software fix.
• 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.

• In the US, the Internal Revenue Service approved a series of tax deductions and credits through at least September 30, 2006.^[30] This amounts to $3150 tax credit for cars purchased between January 1 2006 and September 30 2006. Thereafter the credit dropped to half until an anticipated date of March 31 2007, whereafter it will be $787.50 before disappearing entirely under current tax law on October 1 2007.
• Colorado offers an alternate fuel income tax credit for the purchace of a hybrid and other alternate fuel vehicles. The credit for a 2006 Prius is $3285 and for the 2007, $3013. Used cars are eligible for the credit if the credit hasn't previously been claimed. ^[31]
• Some companies such as Hyperion Solutions,^[32] Bank of America and Google give their employee incentives to purchase hybrid vehicles. Employees of Hyperion Solutions and Google can get a $5000 credit toward their purchase of a hybrid vehicle such as the Prius.
• 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 (currently until July 1, 2008, and requires a special "Clean Fuel Vehicle" licence plate at $25 per year^[33]), California (currently until January 1, 2011,^[34] requires $8 one-time fee for a decal), Florida (requires $5 per year decal), New York and Arizona.^[35]
• Prius drivers in London, UK, are exempt from the £8 daily congestion charge (requires £10 per year registration).
• Prius drivers in Winchester, UK, used to qualify for free parking at a number of the city's car parks (season ticket worth ~ £800 per annum). This has now been discontinued due to lack of funding.
• Prius and other hybrid drivers who purchased a new hybrid in San Jose, California qualified for free parking city wide until July 1 2007.^[36]
• Prius and other hybrid drivers qualify for free parking in metered spaces in the City of Los Angeles, California until December 31 2007.^[37]
• In Canada, starting Jan 1st 2007, Prius qualifies for $2000 instant Federal rebate as well as British Columbia provides additional $2000 rebate on new cars only, totaling $4000 combined discount.

• In June 2007, Avis will offer approximately 1,000 Prius for rental in California, Seattle, and Portland, Oregon. In the same month, Hertz announced plans to add 3,400 Prius to its fleet by 2008.
• The London Borough of Richmond upon Thames replaced its mayoral Daimler Limousine with a black Prius in March 2007.
• The Wall Street Journal reported in 2007 that some blind people find the silence of the cars like the Prius to be a challenge in crossing the street.^[38]

Toyota Motor Corp. said today it has so far sold 1 million hybrid vehicles globally (2007-06-07) ^[39]

The Prius accounted for 40% of the hybrid market in USA in 2006. ^[40]

• As of August 31, 2006, 570,383 units had been sold worldwide, with cumulative sales of over 750,000 Toyota hybrids.^[41]
• As of June 2006, over 60,000 Priuses had been sold in California.
• As of June 7, 2006, 500,000 Priuses had been sold worldwide, 266,212 in the USA alone.
• As of February 2006, the waiting time in Palo Alto, California, was over six months.
• U.S. sales were 53,991 in 2004, and doubled in 2005 to 107,897, about 60% of the world total of 180,000.^[42]
• In January 2005, the Prius became available in South Africa.
• In June 2004, the Wall Street Journal reported that the backlog for 2004 Priuses has reached 22,000 in the USA.
• As of April 2004, the expected delivery time for a Prius in the Netherlands was one year.
• As of March 2004, the waiting list at a Sonoma County, California, dealership was over 100 people long.
• As of February 16, 2004, Toyota USA was not taking new Internet orders for the 2004 Prius.
• As of December 14, 2003, the waiting time in Dallas, Texas, was six months.
• U.S. sales of the Prius began in August 2000. U.S. sales totalled 15,556 in 2001, and 20,119 in 2002.^[43]

When the vehicle is turned-on with the "start" button, it is ready to drive immediately with the electric motor, while electric pumps warm the engine with previously saved hot engine coolant, before the internal combustion engine is started. The delay between starting the car and starting the internal combustion engine is approximately seven seconds. The Asian and European versions of this vehicle provide a button labelled "EV" that maintains Electric Vehicle mode after start up, under most low-load driving conditions. The North American model does not have the "EV" button, although the "EV" mode is still supported internally by the Prius Hybrid Vehicle management computer. While some have speculated that EV mode was not included on North American models in the interest of retaining the longer warranted battery life of 150,000 miles (240,000 km) in certain US states, a Toyota chief engineer has stated that the EV button was omitted because its use can cause the catalytic converter to cool too much, leading to emissions problems^[44]. In addition to information from on-line discussion groups, the PRIUS+ Project^[45] offers instructions for do-it-yourselfers who wish to enable the button.

Plug-in hybrids use a larger battery pack that is recharged from external sources in order to further reduce gas consumption. The batteries in a production PHEV will be built to handle deeper discharge cycles without loss of lifespan such as those in the Toyota RAV4 EV. Operation of the vehicle will be very similar to a normal hybrid, other than the electric operation will be more prevalent. In the case of a Prius PHEV, under high-load situations such as high-speed roads, the gasoline (petrol) engine will operate as before, leaving the car the same ability to accelerate and use freeways. Current converted Prius also operate in a high speed blended mode which can reduce but not eliminate gasoline consumption on the freeway. When driving in slower conditions or other light loads, the batteries will be used first in a charge-depleting mode, allowing moderate commutes at low speeds (particularly under 41 mph/65 km/h) to be driven entirely on electricity. Once the batteries have been sufficiently discharged the car will automatically revert back to the charge-sustaining mode of the current stock Prius. Safe lithium-based batteries exist, eliminating all risk of run-away thermal conditions (spontaneously catch fire or explode) as seen in some laptop computer batteries.

Evolving from the button project, The California Cars Initiative (CalCars)^[46] converted a Prius in 2004, adding larger batteries and found out how to safely charge the batteries without affecting the hybrid system. Private companies EDrive Systems in the USA and Amberjac Projects in the UK announced plans to sell conversion kits in 2006 (pushed back to 2007). The most recent versions use a new, patented advanced safe-format Lithium Battery from Valence Technology called Saphion. Using the advanced batteries pushes the final price to an estimated $12,000 US. The energy density and far more efficient utilisation of these batteries provide around 20x the available power of the standard NiMH battery pack but at only double the weight. Tests show it capable of achieving >30 miles (50 km) in all electric mode at speeds below 34 mph (55 km/h). The internal combustion engine starts only at higher speeds or when extra acceleration is needed. Fuel economy is improved to Template:Mpg - Template:Mpg ^[47] depending on driving conditions. City driving may be possible without using the ICE at all, eliminating the use of almost all liquid fuel in exchange for electrical energy.

PriusPlus^[48] is a similar project evolving from CalCars, using lead-acid batteries and a do-it-yourself kit. This conversion gives a car that has Template:Mpg under normal driving conditions. All-electric mode can be used for 10-12 miles in street driving. In January 2007 issue of IEEE Spectrum, CalCars lead technical engineer, Ron Gremban, notes that drivers installing the CalCars Prius+ kit shouldn’t expect a 'positive financial payback.'^[49] In addition, the kit adds 135 kg to the car's weight, reducing fuel economy over the stock Prius whenever the gasoline engine is used exclusively. The battery pack suffers in cold weather, has a limited life of about 400 deep discharges, and must be recharged within a day to maintain this lifespan. The hope is, by the time the batteries need replacing, a better option is on the market at a comparable price.

Hymotion^[50] is a Canadian company (recently purchased by A123systems, an advanced battery company) planning on selling a kit incorporating Lithium-Ion batteries with similar characteristics as EDrive Systems. It is currently undergoing fleet testing, and is planned for sale for 2008.

• Comparison of Toyota hybrids
• List of hybrid vehicles
• Honda Civic Hybrid
• Better World Club
• Hybrid Synergy Drive
• Hypermiler Driving - Drivers who exceed EPA est MPG
• Hybrid electric vehicle
• Plug-in hybrid electric vehicle
• Toyota Camry Hybrid
• Toyota eCom

Official Sites

• Official USA Prius web site
• Toyota Prius brochure and specifications (pdf) UK
• 24 page document on the THS II system (in PDF, 1.54 MB)

Dmoz

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