Wikicars - User contributions [en]

Hydraulics

2007-01-14T10:46:49Z

Chris:

'''Hydraulics''' is a topic of science and engineering subject dealing with the mechanical properties of liquids. Hydraulics is part of the more general discipline of fluid power.

The word "hydraulics" originates from the Greek word ''ὑδραυλικός'' (''hydraulikos'') which in turn originates from ''ὕδραυλος'' meaning "water organ" which in turn comes from ''ὕδρω'' (water) and ''αὐλός'' (plumbing|pipe). The earliest masters of this art were Hero of Alexandria and Ctesibius. The ancient engineers focused on sacral and novelty uses of hydraulics, rather than practical applications. Ancient Sinhalese used hydraulics in many applications, in the Ancient kingdoms of Anuradhapura, Polonnaruwa etc. The discovery of the principle of the valve tower, or valve pit, for regulating the escape of water is credited to Sinhalese ingenuity more than 2,000 years ago. By the first century A.D, several large-scale irrigation works had been completed. Macro- and micro-hydraulics to provide for domestic horticultural and agricultural needs, surface drainage and erosion control, ornamental and recreational water courses and retaining structures and also cooling systems were in place in Sigiriya, Sri Lanka. Is some stuff that makes things move.

One of the founders of modern hydraulics was Benedetto Castelli, a student of Galileo Galilei.

Fluid mechanics provides the theoretical foundation for hydraulics, which focuses on the engineering uses of fluid properties. Hydraulic topics range through most science and engineering disciplines, and cover concepts such as pipe flow, dam design, fluid control circuitry, pumps, water turbines, hydropower, computational fluid dynamics, flow measurement, river channel behavior and erosion.

==Use in Cars==
[[Image:Hydraulics.jpg|thumb|right|250px|Hydraulics on a [[Chevrolet Impala]]]]
Hydraulics are often placed on older vehicles, though sometimes newer ones. They are not necessary, and provide more "show" than "use." It is not uncommon to see a car "jump" at a car show using hydraulics.

==Source==
History:
[http://en.wikipedia.org/wiki/Hydraulics Wikipedia(distributed under the GNU Free Documentation License)]

Image:
[http://www.clubavalanche.com/forums/index.php?showtopic=4800& Club Avalanche - Image by: wonder91178]

Hydraulics

2007-01-14T10:46:10Z

Chris:

'''Hydraulics''' is a topic of science and engineering subject dealing with the mechanical properties of liquids. Hydraulics is part of the more general discipline of fluid power.

The word "hydraulics" originates from the Greek word ''ὑδραυλικός'' (''hydraulikos'') which in turn originates from ''ὕδραυλος'' meaning "water organ" which in turn comes from ''ὕδρω'' (water) and ''αὐλός'' (plumbing|pipe). The earliest masters of this art were Hero of Alexandria and Ctesibius. The ancient engineers focused on sacral and novelty uses of hydraulics, rather than practical applications. Ancient Sinhalese used hydraulics in many applications, in the Ancient kingdoms of Anuradhapura, Polonnaruwa etc. The discovery of the principle of the valve tower, or valve pit, for regulating the escape of water is credited to Sinhalese ingenuity more than 2,000 years ago. By the first century A.D, several large-scale irrigation works had been completed. Macro- and micro-hydraulics to provide for domestic horticultural and agricultural needs, surface drainage and erosion control, ornamental and recreational water courses and retaining structures and also cooling systems were in place in Sigiriya, Sri Lanka. Is some stuff that makes things move.

One of the founders of modern hydraulics was Benedetto Castelli, a student of Galileo Galilei.

Fluid mechanics provides the theoretical foundation for hydraulics, which focuses on the engineering uses of fluid properties. Hydraulic topics range through most science and engineering disciplines, and cover concepts such as pipe flow, dam design, fluidics|fluid control circuitry, pumps, water turbine|turbines, hydropower, computational fluid dynamics, flow measurement, river channel behavior and erosion.

==Use in Cars==
[[Image:Hydraulics.jpg|thumb|right|250px|Hydraulics on a [[Chevrolet Impala]]]]
Hydraulics are often placed on older vehicles, though sometimes newer ones. They are not necessary, and provide more "show" than "use." It is not uncommon to see a car "jump" at a car show using hydraulics.

==Source==
History:
[http://en.wikipedia.org/wiki/Hydraulics Wikipedia(distributed under the GNU Free Documentation License)]

Image:
[http://www.clubavalanche.com/forums/index.php?showtopic=4800& Club Avalanche - Image by: wonder91178]

Hydraulics

2007-01-14T10:45:52Z

Chris: /* Use in Cars */

'''Hydraulics''' is a topic of science and engineering subject dealing with the mechanical properties of liquids. Hydraulics is part of the more general discipline of fluid power.

The word "hydraulics" originates from the Greek word ''ὑδραυλικός'' (''hydraulikos'') which in turn originates from ''ὕδραυλος'' meaning "water organ" which in turn comes from ''ὕδρω'' (water) and ''αὐλός'' (plumbing|pipe). The earliest masters of this art were Hero of Alexandria and Ctesibius. The ancient engineers focused on sacral and novelty uses of hydraulics, rather than practical applications. Ancient Sinhalese used hydraulics in many applications, in the Ancient kingdoms of Anuradhapura, Polonnaruwa etc. The discovery of the principle of the valve tower, or valve pit, for regulating the escape of water is credited to Sinhalese ingenuity more than 2,000 years ago. By the first century A.D, several large-scale irrigation works had been completed. Macro- and micro-hydraulics to provide for domestic horticultural and agricultural needs, surface drainage and erosion control, ornamental and recreational water courses and retaining structures and also cooling systems were in place in Sigiriya, Sri Lanka. Is some stuff that makes things move.

One of the founders of modern hydraulics was Benedetto Castelli, a student of Galileo Galilei.

[[Fluid mechanics]] provides the theoretical foundation for hydraulics, which focuses on the [[engineering]] uses of fluid properties. Hydraulic topics range through most science and engineering disciplines, and cover concepts such as pipe flow, dam design, fluidics|fluid control circuitry, pumps, water turbine|turbines, hydropower, computational fluid dynamics, flow measurement, river channel behavior and erosion.

==Use in Cars==
[[Image:Hydraulics.jpg|thumb|right|250px|Hydraulics on a [[Chevrolet Impala]]]]
Hydraulics are often placed on older vehicles, though sometimes newer ones. They are not necessary, and provide more "show" than "use." It is not uncommon to see a car "jump" at a car show using hydraulics.

==Source==
History:
[http://en.wikipedia.org/wiki/Hydraulics Wikipedia(distributed under the GNU Free Documentation License)]

Image:
[http://www.clubavalanche.com/forums/index.php?showtopic=4800& Club Avalanche - Image by: wonder91178]

File:Hydraulics.jpg

2007-01-14T10:45:01Z

Chris: Car using hydraulics.

Car using hydraulics.

Hydraulics

2007-01-14T10:43:33Z

Chris:

'''Hydraulics''' is a topic of science and engineering subject dealing with the mechanical properties of liquids. Hydraulics is part of the more general discipline of fluid power.

The word "hydraulics" originates from the Greek word ''ὑδραυλικός'' (''hydraulikos'') which in turn originates from ''ὕδραυλος'' meaning "water organ" which in turn comes from ''ὕδρω'' (water) and ''αὐλός'' (plumbing|pipe). The earliest masters of this art were Hero of Alexandria and Ctesibius. The ancient engineers focused on sacral and novelty uses of hydraulics, rather than practical applications. Ancient Sinhalese used hydraulics in many applications, in the Ancient kingdoms of Anuradhapura, Polonnaruwa etc. The discovery of the principle of the valve tower, or valve pit, for regulating the escape of water is credited to Sinhalese ingenuity more than 2,000 years ago. By the first century A.D, several large-scale irrigation works had been completed. Macro- and micro-hydraulics to provide for domestic horticultural and agricultural needs, surface drainage and erosion control, ornamental and recreational water courses and retaining structures and also cooling systems were in place in Sigiriya, Sri Lanka. Is some stuff that makes things move.

One of the founders of modern hydraulics was Benedetto Castelli, a student of Galileo Galilei.

[[Fluid mechanics]] provides the theoretical foundation for hydraulics, which focuses on the [[engineering]] uses of fluid properties. Hydraulic topics range through most science and engineering disciplines, and cover concepts such as pipe flow, dam design, fluidics|fluid control circuitry, pumps, water turbine|turbines, hydropower, computational fluid dynamics, flow measurement, river channel behavior and erosion.

==Use in Cars==
[[Image:http://www.clubavalanche.com/forums/pthumbs/pimg-1093549098-138525.jpg|thumb|right|250px|Hydraulics on a [[Chevrolet Impala]]
Hydraulics are often placed on older vehicles, though sometimes newer ones. They are not necessary, and provide more "show" than "use." It is not uncommon to see a car "jump" at a car show using hydraulics.

==Source==
History:
[http://en.wikipedia.org/wiki/Hydraulics Wikipedia(distributed under the GNU Free Documentation License)]

Image:
[http://www.clubavalanche.com/forums/index.php?showtopic=4800& Club Avalanche - Image by: wonder91178]

Hydraulics

2007-01-14T10:27:52Z

Chris:

'''Hydraulics''' is a topic of [[science]] and [[engineering]] subject dealing with the mechanical properties of [[liquid]]s. Hydraulics is part of the more general discipline of [[fluid power]].

The word "hydraulics" originates from the [[Greek language|Greek]] word ''{{Polytonic|ὑδραυλικός}}'' (''hydraulikos'') which in turn originates from ''{{Polytonic|ὕδραυλος}}'' meaning [[water organ]] which in turn comes from ''{{Polytonic|ὕδρω}}'' ([[water]]) and ''{{Polytonic|αὐλός}}'' ([[plumbing|pipe]]). The earliest masters of this art were [[Hero of Alexandria]] and [[Ctesibius]]. The ancient engineers focused on sacral and novelty uses of hydraulics, rather than practical applications. Ancient Sinhalese used hydraulics in many applications, in the Ancient kingdoms of [[Anuradhapura]], [[Polonnaruwa]] etc. The discovery of the principle of the valve tower, or valve pit, for regulating the escape of water is credited to Sinhalese ingenuity more than 2,000 years ago. By the first century A.D, several large-scale irrigation works had been completed. Macro- and micro-hydraulics to provide for domestic horticultural and agricultural needs, surface drainage and erosion control, ornamental and recreational water courses and retaining structures and also cooling systems were in place in [[Sigiriya]], [[Sri Lanka]]. Is some stuff that makes things move.

One of the founders of modern hydraulics was [[Benedetto Castelli]], a student of [[Galileo Galilei]].

[[Fluid mechanics]] provides the theoretical foundation for hydraulics, which focuses on the [[engineering]] uses of fluid properties. Hydraulic topics range through most science and engineering disciplines, and cover concepts such as pipe [[flow]], [[dam]] design, [[fluidics|fluid control circuitry]], [[pump]]s, [[water turbine|turbines]], [[hydropower]], [[computational fluid dynamics]], flow measurement, river channel behavior and erosion.

==Source==
[http://en.wikipedia.org/wiki/Hydraulics Wikipedia(distributed under the GNU Free Documentation License)]

Automatic gearbox

2007-01-14T10:25:54Z

Chris:

An '''automatic transmission''' is an [[automobile]] [[gearbox]] that can change [[gear ratio]]s automatically as the car or truck moves, thus freeing the driver from having to shift gears [[manual transmission|manually]]. (Similar but larger devices are also used for [[railroad]] [[Locomotive#Diesel-hydraulic|locomotives]].)

Most cars sold in the [[United States]] since the [[1950s]] have been equipped with an automatic transmission. This has, however, not been the case in [[Europe]] and much of the rest of the world. Automatic transmissions, particularly earlier ones, reduce [[fuel efficiency]] and power. Where fuel is expensive and, thus, engines generally smaller, these penalties are more burdensome. In recent years, automatic transmissions have significantly improved in their ability to support high fuel efficiency but [[manual transmission]]s are still generally more efficient. (This balance may finally shift with the introduction of practical [[continuously variable transmission]]s; see below.)

Most automatic transmissions have a set selection of possible gear ranges, often with a [[parking pawl]] feature that will lock the output shaft of the transmission.

However, some simple machines with limited speed ranges and/or fixed engine speeds only use a [[torque converter]] to provide a variable gearing of the engine to the wheels. Typical examples include [[forklift]] trucks and some modern [[lawn mower]]s.

Recently manufacturers have begun to make '''[[continuously variable transmission]]s''' commonly available (earlier models such as the Subaru Justy did not popularize CVT). These designs can change the ratios over a range rather than between set gear ratios. Even though CVTs have been used for decades in a few vehicles (e.g. [[Van Doorne's Automobiel Fabriek|DAF]] saloons and the [[Volvo 340]] series that succeeded them, and later the [[Subaru Justy]]), the technology has recently gained greater acceptance among manufacturers and customers.

==Hydraulic automatic transmissions==
[[Image:Ford500autotrans.JPG|thumb|right|The [[automatic transmission selector lever]] in a [[Ford Five Hundred]] car]]
[[image:torque-converter-cutbox-model.jpg|thumb|A cut-away model of a [[torque converter]]]]
The predominant form of automatic transmission is [[Hydraulic machinery|hydraulically]] operated, using a [[fluid coupling]] or [[torque converter]] and a set of [[epicyclic gearing|planetary gearsets]] to provide a range of torque multiplication.

===Parts and operation===
A hydraulic automatic transmission consists of the following parts:
*''[[Fluid coupling]]'' or ''[[torque converter]]'': A hydraulic device connecting the engine and the transmission. It takes the place of a mechanical [[clutch]], allowing the engine to remain running at rest without stalling. A torque converter is a fluid coupling that also provides a variable amount of torque multiplication at low engine speeds, increasing "breakaway" acceleration.
*''[[Epicyclic gearing|Planetary gearset]]'': A compound planetary set whose bands and clutches are actuated by hydraulic [[servo]]s controlled by the valve body, providing two or more gear ratios.
*''Valve body'': hydraulic control center that receives pressurised fluid from a ''main pump'' operated by the fluid coupling/torque converter. The pressure coming from this pump is regulated and used to run a network of spring-loaded valves, check balls and [[servo]] pistons. The valves use the pump pressure and the pressure from a [[centrifugal governor]] on the output side (as well as hydraulic signals from the range selector valves and the ''throttle valve'' or ''modulator'') to control which ratio is selected on the gearset; as the car and engine change speed, the difference between the pressures changes, causing different sets of valves to open and close. The hydraulic pressure controlled by these valves drives the various clutch and brake band actuators, thereby controlling the operation of the planetary gearset to select the optimum gear ratio for the current operating conditions. However, in many modern automatic transmissions, the valves are controlled by electro-mechanical servos which are controlled by the Engine Management System or a separate [[Transmission Control Unit|transmission controller]]. (See [[#History and improvements|History and improvements]] below.)

The multitude of parts, along with the complex design of the valve body, originally made hydraulic automatic transmissions much more complicated (and expensive) to build and repair than manual transmissions. In most cars (except US family, luxury, sport-utility vehicle, and minivan models) they have usually been extra-cost options for this reason. Mass manufacturing and decades of improvement have reduced this cost gap.

===History and improvements===
:''See also [[Evolution of the Automatic Transmission]]''
[[Oldsmobile]]'s 1940 models featured [[Hydra-Matic]] drive, the first mass-production fully automatic transmissions. Initially an Olds exclusive, Hydra-Matic had a [[fluid coupling]] (not a torque converter) and three planetary gearsets providing four speeds plus reverse. Hydra-Matic was subsequently adopted by [[Cadillac]] and [[Pontiac]], and was sold to various other automakers, including [[Bentley Motors Limited|Bentley]], [[Hudson Motor Car|Hudson]], [[Kaiser Motors|Kaiser]], [[Nash Motors|Nash]], and [[Rolls-Royce Limited|Rolls-Royce]]. From 1950 to 1954 [[Lincoln (automobile)|Lincoln]] cars were also available with GM Hydra-Matic. [[Mercedes-Benz]] subsequently devised a four-speed fluid coupling transmission that was similar in principle to Hydra-Matic, but did not share the same design.

The first torque converter automatic, [[Buick]]'s [[Dynaflow]], was introduced for the 1948 model year. It was followed by Packard's [[Ultramatic]] in mid-1949 and [[Chevrolet]]'s [[Powerglide]] for the 1950 model year. Each of these transmissions had only two forward speeds, relying on the torque converter for additional gear reduction. In the early 1950s [[Borg-Warner]] developed a series of three-speed torque converter automatics for [[American Motors Corporation]], [[Ford Motor Company]], [[Studebaker]], and several other manufacturers in the US and other countries. [[Chrysler Corporation|Chrysler]] was late in developing its own true automatic, introducing the two-speed torque converter [[PowerFlite]] in 1953 and the three-speed [[TorqueFlite]] in 1956.

By the late 1960s most of the fluid-coupling four-speeds and two-speed transmissions had disappeared in favor of three-speed units with torque converters. By the early 1980s these were being supplemented and eventually replaced by [[overdrive (mechanics)|overdrive]]-equipped transmissions providing four or more forward speeds. Many transmissions also adopted the lock-up torque converter (a mechanical clutch locking the torque converter impeller and turbine together to eliminate slip at cruising speed) to improve fuel economy.

As the [[electronic control unit|engine computer]]s became more and more capable, even more of the valve body's functionality was offloaded to them. These transmissions, introduced in the late 1980s and early 1990s, remove almost all of the control logic from the valve body, and place it in into the engine computer. (Some manufacturers use a separate computer dedicated to the transmission but sharing information with the engine management computer.) In this case, [[solenoid]]s turned on and off by the computer control shift patterns and gear ratios, rather than the spring-loaded valves in the valve body. This allows for more precise control of [[shift point]]s, shift quality, lower shift times, and (on some newer cars) semi-automatic control, where the driver tells the computer when to shift. The result is an impressive combination of efficiency and smoothness. Some computers even identify the driver's style and adapt to best suit it.

[[ZF Friedrichshafen AG]] and [[BMW]] were responsible for introducing the first five-speed automatic (the [[ZF 5HP18 transmission|ZF 5HP18]] in the 1992 [[BMW]] [[BMW E34|E34]] [[BMW 5-Series|5-Series]]) and the first six-speed (the [[ZF 6HP26 transmission|ZF 6HP26]] in the 2002 [[BMW]] [[BMW E65|E65]] [[BMW 7-Series|7-Series]]). [[Mercedes-Benz]]'s [[7G-TRONIC]] was the first seven-speed in 2003, with [[Toyota Motor Company]] introducing an 8-speed in 2007 on the [[Lexus LS]] 460 and 600.

==Automatic transmission modes==

In order to select the mode, the driver must move a gear shift lever which can be located on the steering column or on the floor next to the driver. In order to select gears/modes the driver must push a button in (called the shift lock button) or pull the handle (only on column mounted shifters) out.

Automatic Transmissions have various modes depending on the model and make of the transmission. Some of the common modes are:

'''Park (P)''' – This selection mechanically locks the transmission, restricting the car from moving in any direction. A pin prevents the transmission from moving forward (although wheels, depending on the drive train, can still spin freely), it is recommended to use the [[hand brake]] (or emergency brake) because this actually locks the wheels and prevents them from moving, and increases the life of the transmission and the park mechanism. In order for the car to be moved out of park, the driver must depress the brake fully, same goes for putting it into park. The driver also must come to a complete stop before putting it into park to prevent damage to the transmission. This is only one of two selections in which the car can be started.

'''Reverse (R)''' – This puts the car into the reverse gear, giving the ability for the car to back up. In order for the driver to select reverse they must come to a complete stop, and push the shift lock button in and select reverse. Not coming to a complete stop can cause severe damage to the transmission.

'''Neutral/No gear (N)'''– This disconnects the transmission from the wheels so the car can move freely under its own weight. This is the only other selection in which the car can be started.

'''Drive (D)'''– This allows the car to move forward and accelerate through a range of gears. The number of gears a transmission has depends on the model, but they can commonly range from 3, 4 (the most common), 5, 6 (found in [[VW]]/[[Audi]] [[Direct Shift Gearbox]]), and 8 in the new model of Lexus cars.
*'''D4''' – In [[Honda]] and [[Acura]] automatics this mode is used commonly for highway use (as stated in the manual) and uses all 4 forward gears.
*'''D3''' – This is also found in Honda and Acura automatics and only uses the first 3 gears and according to the manual it is used for ''stop & go traffic'' such as city driving.
* '''+ - and M''' – This is the manual selection of gears for automatics with [[Tiptronic]]. The driver can shift up and down at their will.

'''Second (2 or S)''' – This mode limits the transmission to the first two gears, or more commonly locks the transmission in second gear. This can be used to drive in adverse conditions such as [[snow]] and ice, as well as climbing or going down hills in the winter time.

'''First (1 or L)''' – This mode locks the transmission in first gear only. It will not accelerate through any gear range. This, like second, can be used during the winter season, or towing.

Some cars when put into D will automatically lock the doors or turn on the daytime running lights.

== Automatic Transmission Models ==
Some of the best known automatic transmission families include:
* [[List of GM transmissions|General Motors]] — [[Powerglide]], [[Turbo-Hydramatic]] 350 and 400, [[GM 4L60-E transmission|4L60-E]], [[GM 4L80-E transmission|4L80-E]]
* [[List of Ford transmissions|Ford]]: [[Cruise-O-Matic]], [[Ford C4 transmission|C4]], [[Ford C6 transmission|C6]], [[Ford AOD transmission|AOD/AODE]], [[Ford E4OD transmission|E4OD]], [[Ford ATX transmission|ATX]], [[Ford AXOD transmission|AXOD/AX4S/AX4N]]
* [[List of Chrysler transmissions|Chrysler]]: [[TorqueFlite]] 727 and 904, A500, A518, 45RFE, 545RFE
* [[BorgWarner]] (later [[Aisin AW]])
* [[List of ZF transmissions|ZF Friedrichshafen AG]]
* [[Allison Transmission]]
* [[Voith Turbo]]
* [[List of Aisin transmissions|Aisin AW]]; Aisin AW is a Japanese automotive parts supplier, known for its automatic transmissions and navigation systems
* [[List of Honda transmissions|Honda]]
* [[List of Jatco transmissions|Nissan/Jatco]]

Automatic transmission families are usually based on [[Ravigneaux]], [[Lepelletier]], or Simpson [[Epicyclic gearing|planetary gear]]sets. Each uses some arrangement of one or two central sun gears, and a ring gear, with differing arrangements of planet gears that surround the sun and mesh with the ring. An exception to this is the [[Hondamatic]] line from [[Honda]], which uses sliding gears on parallel axes like a manual transmission without any planetary gearsets. Although the Honda is quite different from all other automatics, it is also quite different from an automated manual transmission.

==Continuously variable transmissions==
{{main|continuously variable transmission}}

A different type of automatic transmission is the ''continuously variable transmission'' or ''CVT'', which can smoothly alter its [[gear ratio]] by varying the diameter of a pair of [[belt (mechanical)|belt]] or [[roller chain|chain]]-linked [[pulley]]s, [[wheel]]s or [[cone (mechanical)|cone]]s. Some continuously variable transmissions use a [[hydrostatic drive]] consisting of a [[variable displacement pump]] and a hydraulic motor to transmit power without gears. CVT designs are usually as fuel efficient as manual transmissions in city driving, but early designs lose efficiency as engine speed increases.

A slightly different approach to CVT is the concept of ''[[toroidal CVT]]'' or ''[[Continuously variable transmission#infinitely variable transmission|IVT]]'' (from infinitely variable transmission). These concepts provide zero and reverse gear ratios.

Some current hybrid vehicles, notably those of [[Toyota]], [[Lexus]] and [[Ford Motor Company]], have an "electronically-controlled CVT" ([[E-CVT]]). In this system, the transmission has fixed gears, but the ratio of wheel-speed to engine-speed can be continuously varied by controlling the speed of the third input to a [[Differential_(mechanics)|differential]] using an [[electric motor]]-[[Electrical generator|generator]].

==Manually controlled automatic transmissions==
Most automatic transmissions offer the driver a certain amount of manual control over the transmission's shifts (beyond the obvious selection of forward, reverse, or neutral). Those controls take several forms:
* ''Throttle kickdown'': Most automatic transmissions include a switch on the throttle linkage that will force the transmission to downshift into the next lower ratio if the throttle is fully engaged. The switch generally only functions up to a certain road speed, so as to prevent a downshift that would overrev the engine. Some transmissions also have a part-throttle kickdown, eliminating the need to "floorboard" the throttle to downshift.
* ''Low gear ranges'': Many transmissions have switches or selector positions that allow the driver to limit the maximum ratio that the transmission may engage. On older transmissions, this was accomplished by a mechanical lockout in the transmission valve body preventing an upshift until the lockout was disengaged; on computer- controlled transmissions, the same effect is accomplished electronically. The transmission can still upshift and downshift automatically between the remaining ratios: for example, in the ''3'' range, a transmission could shift from first to second to third, but not into fourth or higher ratios. Some transmissions will still upshift automatically into the higher ratio if the engine reaches its maximum permissible speed in the selected range.
* ''Manual controls'': Some transmissions have a mode in which the driver has full control of ratio changes (either by moving the selector or through the use of buttons or paddles), completely overriding the hydraulic controller. Such control is particularly useful in cornering, to avoid unwanted upshifts or downshifts that could compromise the vehicle's balance or traction. "Manumatic" shifters, first popularized by [[Porsche]] in the [[1990s]] under the [[trade name]] [[Tiptronic]], have become a popular option on [[sports cars]] and other performance vehicles. With the near-universal prevalence of electronically controlled transmissions, they are comparatively simple and inexpensive, requiring only software changes and the provision of the actual manual controls for the driver. The amount of true manual control provided is highly variable: some systems will override the driver's selections under certain conditions, generally in the interest of preventing engine damage.

Some automatic transmissions modified or designed specifically for [[drag racing]] may also incorporate a transmission brake, or "trans-brake," as part of a manual valve body. Activated by electrical solenoid control, a trans-brake simultaneously engages the first and reverse gears, locking the transmission and preventing the input shaft from turning. This allows the driver of the car to raise the engine rpm against the resistance of the torque converter, then launch the car by simply releasing the trans-brake switch.

==See also==
* [[AMC and Jeep transmissions]]
* [[Hydraulics]]

==External links==
*[http://auto.howstuffworks.com/automatic-transmission.htm How Automatic Transmissions Work] on [[HowStuffWorks]]
*[http://www.wikihow.com/Drive-a-Car-With-an-Automatic-Transmission How To Drive a Car with Automatic Transmission]
*[http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US5370589&F=0| US5370589 Lepelletier's concept is shown on this patent]
*[http://www.toomonline.com/gearboxlinks.htm Randolph Toom webpage] — a survey of current automatic transmissions
*[http://www.torotrak.com Articles related to IVT]
*[http://www.allisontransmission.com Allison Transmission Website]
*[http://www.powertraincontrolsolutions.com PCS Automatic Transmission Controller Website]
*[http://www.AWshifting.com Automatic Transmission Controllers]

==Source==
*[http://en.wikipedia.org/wiki/Automatic_gearbox Wikipedia(distributed under the GNU Free Documentation License]

Rolls-Royce Phantom VI

2007-01-14T10:19:31Z

Chris:

{| border=0 cellspacing=0 cellpadding=4 style="float:right; margin:0 0 .5em 1em; width:250px; background:#fff; border-collapse:collapse; border:1px solid #999; font-size:83%; line-height:1.5; " summary="Infobox Automobile"
|- style="text-align:center; background:#f0f0f0;"
| colspan=2 style="padding:0; background:#996; color:#fff; border-bottom:1px solid #999;" |
|- style="color:#fff; background:#996; font-size:larger;"
! colspan=2 | '''Rolls-Royce Phantom VI'''
|-
! colspan=2 style="text-align:center; font-weight:normal; background:#ddb;" | [[Rolls-Royce]]
|
|- style="vertical-align:top; background:#f0f0f0;"
| Production: 1968–1991 - 374 produced
|
|- style="vertical-align:top;"
| Class: Exclusive Luxury
|
|- style="vertical-align:top;"
| Length: 6.05 m (238 in)
|
|- style="vertical-align:top; background:#f0f0f0;"
| Wheelbase: 3.683 m (145 in)
|
|- style="vertical-align:top;"
| Weight: 2.5 tons (approx)
|
|- style="vertical-align:top; background:#f0f0f0;"
| Transmission: 3-speed automatic (4-speed automatic was also available)
|
|- style="vertical-align:top;"
| Engine: 6.2L V8 - 6.75L V8
|
|}
The '''Phantom VI''' was an ultra-exclusive [[Rolls-Royce car|Rolls-Royce]] model from the 1970s and 1980s produced in London at [[Mulliner Park Ward]]. It was made from 1968-1991.

Though it had been expressed that the days of motor cars of the like of the [[Rolls-Royce Phantom V]] were undoubtedly numbered, in 1968 [[Rolls-Royce Limited|Rolls-Royce]] launched the Phantom VI as a logical progression keeping up the high standards set in the past. The Phantom VI had a re-styled facia and was powered by an engine developed from that of the current [[Rolls-Royce Silver Shadow]]. An increase in capacity to 6,750 cc in 1979 was coupled with the introduction of a 3-speed [[automatic transmission]] instead of the previously employed 4-speed automatic gearbox. This last specimen of a passenger motor car with separate chassis produced by Rolls-Royce was offered until 1991. The chassis used coil springing all round and the car used drum brakes.

Most of the bodies were by [[Mulliner Park Ward]] usually limousines but a few [[landaulette]]s were also made.

==Engine==

The Phantom had a 90 degree V8 with a capacity of 6,230 cc with a bore of 104 mm and stroke of 91.5 mm. This was raised in 1982 to 6,750 cc by fitting the engine from the [[Rolls-Royce Silver Spirit]]. Twin SU carburettors were fitted. The car had a 4-speed [[automatic gearbox]] (from 1979 a 3-speed automatic gearbox with torque converter became standard).

When production ended 374 had been made.

{{Rolls-Royce}}

[[Category:Current Models]]
[[Category:Rolls-Royce vehicles|Phantom 6]]
[[Category:Cars of England]]

{{Classicpow-auto-stub}}

Rolls-Royce Phantom VI

2007-01-14T10:16:39Z

Chris:

{| border=0 cellspacing=0 cellpadding=4 style="float:right; margin:0 0 .5em 1em; width:250px; background:#fff; border-collapse:collapse; border:1px solid #999; font-size:83%; line-height:1.5; " summary="Infobox Automobile"
|- style="text-align:center; background:#f0f0f0;"
| colspan=2 style="padding:0; background:#996; color:#fff; border-bottom:1px solid #999;" | {{{Image}}}
|- style="color:#fff; background:#996; font-size:larger;"
! colspan=2 | '''Rolls-Royce Phantom VI'''
|-
! colspan=2 style="text-align:center; font-weight:normal; background:#ddb;" | [[Rolls-Royce]]
|
|- style="vertical-align:top; background:#f0f0f0;"
| Production: 1968–1991 | 374 produced
|
|- style="vertical-align:top;"
| Class: Exclusive Luxury
|
|- style="vertical-align:top; background:#f0f0f0;"
| Body Style
|
|- style="vertical-align:top;"
| Length: 6.05 m (238 in)
|
|- style="vertical-align:top; background:#f0f0f0;"
| Wheelbase: 3.683 m (145 in)
|
|- style="vertical-align:top;"
| Weight: 2.5 tons (approx)
|
|- style="vertical-align:top; background:#f0f0f0;"
| Transmission: 3-speed automatic (4-speed automatic was also available)
|
|- style="vertical-align:top;"
| Engine: 6.2L V8 - 6.75L V8
|
|}
The '''Phantom VI''' was an ultra-exclusive [[Rolls-Royce car|Rolls-Royce]] model from the 1970s and 1980s produced in London at [[Mulliner Park Ward]]. It was made from 1968-1991.

Though it had been expressed that the days of motor cars of the like of the [[Rolls-Royce Phantom V]] were undoubtedly numbered, in 1968 [[Rolls-Royce Limited|Rolls-Royce]] launched the Phantom VI as a logical progression keeping up the high standards set in the past. The Phantom VI had a re-styled facia and was powered by an engine developed from that of the current [[Rolls-Royce Silver Shadow]]. An increase in capacity to 6,750 cc in 1979 was coupled with the introduction of a 3-speed [[automatic transmission]] instead of the previously employed 4-speed automatic gearbox. This last specimen of a passenger motor car with separate chassis produced by Rolls-Royce was offered until 1991. The chassis used coil springing all round and the car used drum brakes.

Most of the bodies were by [[Mulliner Park Ward]] usually limousines but a few [[landaulette]]s were also made.

==Engine==

The Phantom had a 90 degree V8 with a capacity of 6,230 cc with a bore of 104 mm and stroke of 91.5 mm. This was raised in 1982 to 6,750 cc by fitting the engine from the [[Rolls-Royce Silver Spirit]]. Twin SU carburettors were fitted. The car had a 4-speed [[automatic gearbox]] (from 1979 a 3-speed automatic gearbox with torque converter became standard).

When production ended 374 had been made.

{{Rolls-Royce}}

[[Category:Current Models]]
[[Category:Rolls-Royce vehicles|Phantom 6]]
[[Category:Cars of England]]

{{Classicpow-auto-stub}}