Toyota Prius
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- Prius redirects here. For the Japanese personal computer, see Hitachi Flora Prius.
The Toyota Prius is one of the world's first commercially mass-produced and marketed hybrid automobiles. 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 "before" or "first". The Prius (2000 to 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 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 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.
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How it works
The Prius has been called a true hybrid vehicle, designed from the bottom up. Toyota's goal for the Prius was to reduce the amount of emissions it produced 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 motors, reducing gasoline consumption. The Prius uses the more efficient Atkinson cycle engine instead of the more common Otto cycle;
- Two electric motor/generators, providing 67 hp (50 kW) @ 1200 to 1540 rpm and 400 N•m (295 ft•lbf) torque from 0 to 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 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) battery providing 201.6 volts;
- Continuously variable transmission -- the Prius does not use a typical CVT; Toyota calls it the 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 Prius uses energy that would be otherwise wasted: i.e. when braking, the kinetic energy is partly recovered to recharge the battery instead of being wasted as heat and brake wear.
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 to 2005 Prius
The Prius 2004 model year was a complete redesign of the previous generations of Prius. The new model is based off the new (third generation) Hybrid Synergy Drive (HSD), replacing the earlier Toyota Hybrid System (THS) technology. The first generation (1997 to 2003) could not run its air conditioning unless the motor was running. In contrast, the 2004 model introduced an all-electric compressor for cooling. This allowed more extensive use of the "stealth mode" (operation on electric motor only).
The drag coefficient of 0.26 was now the second-lowest in the industry, after the smaller 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 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 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.
With a smaller and lower voltage NiMH battery and an inverter 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, with 60 miles per US gallon (4.7 L/100 km) city and 51 miles per US gallon (5.5 L/100 km) highway (according to the EPA). When driven appropriately, commuting and mixed suburban drivers are reporting fuel consumption of 45 to 50 miles per US gallon (6.3 to 5.7 L/100 km). See also [1]
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 + 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.
A Smart Entry/Smart Start (SE/SS) option 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 SE/SS system. Approaching to within 1 meter of the car while in-posession of the key (even inside a pocket or purse) causes the interior dome lights to fade up (at night). When the person with the key in their posession touches either of the front doors, or the rear hatchback door, that door is immediately unlocked and can be opened. Toyota dealers can program the functionality of the SE/SS system to control which doors are unlocked by this method. Once parked, the car can be locked by a pushing a black button on the exterior door handle. The SE/SS system will detect keys left inside the vehicle when powered-off, and will not allow the vehicle to be locked in this situation.
There is no conventional ignition switch which needs to be turned to start the Prius, that function having been replaced by a simple round "Power" button on the dashboard. With the SE/SS models, the driver need only sit down inside the vehicle (with the fob in their posession), press the brake with their foot and push the "Power" button to start the vehicle. On cars which are not equipped with SE/SS, 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 CARB (California Air Resources Board).
As an interesting side note, a $2,200 option package offered in Japan gives the Prius the ability to perform parallel parking assisted by the on-board computer. 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. [2]
When the vehicle is turned-on with the "start" button, it is ready to drive immediately in "EV" (electric vehicle) mode, before the internal combustion engine is started to heat-up the emissions control system (including the catalytic converter). 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 startup, 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 high-voltage management computer. While some have speculated that EV mode was not included on North American models in the interest of retaining the warranted battery life of 100,000 miles (160,000 km) in the US - 150,000 miles (240,000 km) in California and several other states, engineers note that EV mode is automatically overridden when the battery requires recharging from the internal combustion engine. The Prius is designed to protect the battery from extreme discharge as well as over-charge and will utilize the engine as-necessary to maintain the optimum conditions for a long battery life. In addition to information at online discussion groups, the PRIUS+ Project offers instructions for do-it-yourselfers who wish to enable the button, and aftermarket components provider Coastal Electronic Technologies offers a kit.
Evolving from the button project, The California Cars Initiative (CalCars) converted a Prius in 2004, adding larger batteries, and private companies EDrive Systems in the USA and Amberjac Projects in the UK 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.
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 personal imports have been made to the United Kingdom, Australia, and New Zealand. Subsequent versions have seen wider sales, increased power and reduced battery weight.
| Feature | Model code | |||
| NHW10 | NHW11 | NHW20 | ||
| Body style | 4 Door Sedan | 4 Door Sedan | 5 Door Hatchback | |
| First sales | 1997 | 2000 | 2003 | |
| Battery | Modules | 40 | 38 | 28 |
| Cells per module | 6 | 6 | 6 | |
| Total cells | 240 | 228 | 168 | |
| Volts per cell | 1.2 | 1.2 | 1.2 | |
| Total volts (nominal) | 288 | 273.6 | 201.6 | |
| Capacity amp hours | 6.0 | 6.5 | 6.5 | |
| Weight kg | 57 | 50 | 45 | |
| Petrol Engine | Power kW | 43 | 52 | 57 |
| Max rpm | 4000 | 4500 | 5000 | |
| Electric Motor | Power kW | 30 | 33 | 50 |
Awards
- 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.
- 2005 European Car of the Year (Toyota Prius 2nd generation with 406 points, ahead of Citroën C4 with 267 points and Ford Focus II with 228) [3]
Notable facts
- 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 (requires $8 one-time fee for a decal) and Florida (requires $5 per year decal).
- Los Angeles city and San Jose, California allow free parking at meters for hybrid vehicles within the posted time limits, including the Prius.
- Prius drivers in London, UK, are exempt from the £8 ($14) daily congestion charge (requires £10 per year registration).
- Due to the success of both the engineering and sales of the Prius, in 2005, Toyota has released a hybrid V-6 engine for the Lexus RX400h and 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 Prius fuel tank holds 45 litres (11.9 US gal), 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 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 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 occurred to the cars that didn't receive the software fix. Some supporters argued that 33 cases (of which some were duplicate reports and/or valid out-of-gas conditions) among 75000+ cars sold was not an alarming percentage figure compared to the millions other auto makers have recalled. Besides, the Prius is safer than any other car with a failed engine, as the Prius can still run with its electric motor until it can stop at a safe location.
- Larry David, co-creator of Seinfeld and star of Curb Your Enthusiasm drives a Prius.
- Bill Maher, host of the HBO series Real Time with Bill Maher, drove a Prius for 3 years before trading it in for the Lexus RX 400h hybrid.
- Not only did actor Leonardo Dicaprio buy himself a Prius, he bought several for others in his family.
- In Gilmore Girls, Rory drives a first generation Prius which she received as a high school graduation gift from her grandparents.
- Brian Griffin of the show Family Guy drives a Prius (which inexplicably appeared in the fourth season of the show).
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 April 2004, the expected delivery time for Prius in the Netherlands is 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 is not taking new internet orders for the 2004 Prius.
- As of December 14, 2003, the waiting time in Dallas, Texas, USA, was 6 months.
Car rental
Many Toyota dealerships offer car rentals, allowing prospective buyers to try the Prius. EV Rental Cars, in partnership with Fox Rent-a-Car, offers the Prius for rent at the airports in Phoenix, San Francisco, San Jose, Oakland, Orange County, Los Angeles, and San Diego.
Driving tricks to reduce fuel consumption
Stop shutdown
(Transmission mode in B, speed zero)
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 D (drive) - the engine will stop immediately - at least in 2004 US versions.
Off throttle shift to electric mode
(Transmission mode in D, cruising speed up to 45 mph (70 km/h), road level.)
When reaching cruising speed it is often possible to briefly go "off throttle", allowing the system to switch to electric only mode. If the road is nearly level a gentle re-application of throttle to just enough to maintain cruising speed in electric mode may enable electric cruising (depending upon road grade, wind conditions, and battery state).
Accelerate from stop to 35 to 45 mph (60 to 70 km/h)
(Transmission mode in D, cruising speed up to 45 mph (70 km/h), road level.)
When running in traffic, a brisk (but not full throttle) acceleration, followed by an off throttle attempt (see previous) will be much more effective than gentle acceleration. This is a general technique applicable to non-hybrid cars. A gasoline ICE engine is more efficient (in terms of power produced/fuel consumption) when operating at higher effort due to smaller throttle losses. This is less important for compression-ignition engines, which do not have throttles but are instead regulated by the amount of fuel provided directly to the cylinder.
Accelerate with no traffic to 25 mph (40 km/h)
Transmission mode in D, cruising speed up to 25 mph (40 km/h), road level.
With substantial patience it is possible to accelerate to cruising speed using only electric power. Owing to the slow acceleration this should not be attempted with following traffic present. Although this will temporarily reduce fuel consumption since you're driving in electric mode, it will not improve the long term fuel consumption, since you have to recharge the battery at some point later (and the generation and use of electricity involve energy conversion losses). As pointed out above, it is better to accelerate at a moderate pace.
Long uphill followed by long downhill
(Transmission mode in D, cruising speed uphill to 65 mph (105 km/h), road uphill, followed by downhill at or below 50 mph (80 km/h) with transmission mode in B.)
The controller is blind to the future; it cannot tell that it would make sense to run the battery down on a long upgrade knowing that it can be quickly recharged on a subsequent downgrade. Nor is it possible for the driver to inform the system that this condition is coming. What happens is that the system will use the engine power when going uphill to charge the battery to normal state. Then, running down hill (with "B" selected) the battery is quickly charged to the maximum before the bottom of the hill. This full charge (battery state shown in green) will then cause the system to use the motor for compressive braking. It would be far more efficient to be able to use the battery capability to assist the motor (rather than taking charge from the motor). A run up the hill at sufficient throttle to demand electric motor assist (within speed limits, both statutory and by road and traffic conditions) may improve overall efficiency in this particular circumstance.
Downhill run
When using "B" on a long (1 to 2 km) downhill (e.g. over 60 mph, 100 km/h) you may find at higher speeds that the motor is used for braking in addition to the power recovery from the generator. Unless the battery is fully charged (showing green on the monitor), this is wasting excess energy which could be stored. By briefly braking to a somewhat slower speed, say 45 to 50 mph (70 to 80 km/h), the motor will not be used to retard the vehicle, all subsequent retarding energy will go to the battery, and a longer time will be spent recovering energy, and so more energy will be recovered. This is less useful on a long mountain downgrade where the battery will become fully charged regardless of the technique used,.
Gentle rise and descent
A small amount of additional throttle will accelerate the vehicle before the rise is reached and this additional power may be maintained on most of the upgrade. Reducing throttle and paying off the excess speed before the top is reached may enable electric cruise to be entered, with energy recovery on the downgrade. Reapply cruising throttle at the bottom of the hill when reduction to normal cruise speed is obtained.
Slow steady speed
When traveling on relatively flat surfaces at approx 0 to 25 km/h (15 mph), sometimes the engine will run seemingly unnecessarily. By applying the brakes it tells the car to regenerate and is usually enough to shut it down. Sometimes it is necessary to come to a complete stop. At speeds that low, there is no real need for the gas engine. Alternatively, in the US one could re-enable the EV-Mode Button which is standard in EU and JP Prii, this feature allows the driver to request that the engine not start during times when it may not be needed.
See also
- Toyota Motor Corporation
- Hybrid vehicle
- Plug-in hybrid electric vehicle
- Hypermiler Driving
- Hybrid Synergy Drive
External links
- Official Worldwide Prius Site
- Toyota Prius brochure and specifications (pdf) UK
- Official USA Prius web site
- Toyota's paper on how the 2004 Prius is different from earlier models (in PDF, 2 MB)
- Information, tips, and photos about Prius at John's web site
- PriusChat.com — forums
- PriusOnline forum
- Yahoo! Groups about the Prius
- Toyota - Prius Marathoners Top 100MPG!
- Prius Owners Group - a portal site for Prius Owners and those interested in the Prius
- Mr. Kash's Prius Page — Many links to Prius news stories and reviews.
- PRIUS+ page at CalCars.org - Nonprofit group is converting '04-'05 Priuses into plug-in hybrids
News articles
- BBC: Prius not just a car - it is a phenomenon
- Automotive Industries article
- Toyota Prius is 2005 European Car of the Year
Categories: Cleanup from October 2005 | Toyota vehicles | Hybrid vehicles | Front wheel drive vehicles
