Automatic transmission - Revision history

Red marquis: /* External links */

2009-09-27T19:03:32Z

External links

← Older revision		Revision as of 19:03, 27 September 2009
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	[[Category:Automotive transmission technologies]]		[[Category:Automotive transmission technologies]]
	[[Category:Auto parts]]		[[Category:Auto parts]]
			[[Category:Transmissions]]

PNiddy at 21:21, 24 April 2007

2007-04-24T21:21:44Z

← Older revision		Revision as of 21:21, 24 April 2007
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	{{transmission types}}		{{transmission types}}
	An '''[[Automatic transmission\|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~~.)		An '''[[Automatic transmission\|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 railroads.)

	Most cars sold in the United States since the 1950s have been equipped with an [[Automatic transmission\|automatic]] transmission. This has, however, not been the case in Europe and much of the rest of the world. [[Automatic transmission\|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 transmission\|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 cars sold in the United States since the 1950s have been equipped with an [[Automatic transmission\|automatic]] transmission. This has, however, not been the case in Europe and much of the rest of the world. [[Automatic transmission\|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 transmission\|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.)

PNiddy: Reverted edits by 207.235.214.226 (207.235.214.226); changed back to last version by Red marquis

2007-04-24T21:21:23Z

Reverted edits by 207.235.214.226 (207.235.214.226); changed back to last version by Red marquis

← Older revision		Revision as of 21:21, 24 April 2007
Line 1:		Line 1:
	{{transmission types}}		{{transmission types}}
	An '''[[Automatic transmission\|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.)~~and many other tasks~~		An '''[[Automatic transmission\|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.)

	Most cars sold in the United States since the 1950s have been equipped with an [[Automatic transmission\|automatic]] transmission. This has, however, not been the case in Europe and much of the rest of the world. [[Automatic transmission\|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 transmission\|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 cars sold in the United States since the 1950s have been equipped with an [[Automatic transmission\|automatic]] transmission. This has, however, not been the case in Europe and much of the rest of the world. [[Automatic transmission\|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 transmission\|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.)

207.235.214.226 at 15:22, 24 April 2007

2007-04-24T15:22:00Z

← Older revision		Revision as of 15:22, 24 April 2007
Line 1:		Line 1:
	{{transmission types}}		{{transmission types}}
	An '''[[Automatic transmission\|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.)		An '''[[Automatic transmission\|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.)and many other tasks

	Most cars sold in the United States since the 1950s have been equipped with an [[Automatic transmission\|automatic]] transmission. This has, however, not been the case in Europe and much of the rest of the world. [[Automatic transmission\|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 transmission\|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 cars sold in the United States since the 1950s have been equipped with an [[Automatic transmission\|automatic]] transmission. This has, however, not been the case in Europe and much of the rest of the world. [[Automatic transmission\|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 transmission\|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.)

Red marquis at 02:55, 12 December 2006

2006-12-12T02:55:06Z

← Older revision		Revision as of 02:55, 12 December 2006
Line 35:		Line 35:
	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 and shift quality, and (on some newer cars) also allows semi-[[Automatic transmission\|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.		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 and shift quality, and (on some newer cars) also allows semi-[[Automatic transmission\|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 transmission\|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]].		[[ZF\|ZF Friedrichshafen AG]] and [[BMW]] were responsible for introducing the first five-speed [[Automatic transmission\|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]].

	== [[Automatic transmission\|Automatic]] Transmission Models ==		== [[Automatic transmission\|Automatic]] Transmission Models ==

Rfujitani: Reverted edits by 130.191.152.21 (130.191.152.21); changed back to last version by Carguy

2006-11-27T19:05:09Z

Reverted edits by 130.191.152.21 (130.191.152.21); changed back to last version by Carguy

← Older revision		Revision as of 19:05, 27 November 2006
Line 62:		Line 62:

	==Manually controlled [[Automatic transmission\|automatic]] transmissions==		==Manually controlled [[Automatic transmission\|automatic]] transmissions==
	Most [[Automatic transmission\|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). ~~These are offered for yuppies who drive BMW 325s who are incapable of learning to shift a real manual gearbox.~~ Those controls take several forms:		Most [[Automatic transmission\|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 transmission\|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 had a part-throttle kickdown, obviating the need to "floorboard" the throttle to downshift.		* ''Throttle kickdown'': Most [[Automatic transmission\|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 had a part-throttle kickdown, obviating 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.		* ''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.

130.191.152.21: /* Manually controlled automatic transmissions */

2006-11-27T15:05:41Z

Manually controlled automatic transmissions

← Older revision		Revision as of 15:05, 27 November 2006
Line 62:		Line 62:

	==Manually controlled [[Automatic transmission\|automatic]] transmissions==		==Manually controlled [[Automatic transmission\|automatic]] transmissions==
	Most [[Automatic transmission\|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:		Most [[Automatic transmission\|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). These are offered for yuppies who drive BMW 325s who are incapable of learning to shift a real manual gearbox. Those controls take several forms:
	* ''Throttle kickdown'': Most [[Automatic transmission\|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 had a part-throttle kickdown, obviating the need to "floorboard" the throttle to downshift.		* ''Throttle kickdown'': Most [[Automatic transmission\|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 had a part-throttle kickdown, obviating 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.		* ''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.

Carguy at 17:34, 5 July 2006

2006-07-05T17:34:14Z

← Older revision		Revision as of 17:34, 5 July 2006
Line 1:		Line 1:
			{{transmission types}}
	An '''[[Automatic transmission\|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.)		An '''[[Automatic transmission\|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.)

Carguy at 17:28, 5 July 2006

2006-07-05T17:28:51Z

← Older revision		Revision as of 17:28, 5 July 2006
Line 1:		Line 1:
	~~{{transmission types}}~~
	An '''[[Automatic transmission\|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.)		An '''[[Automatic transmission\|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.)

Carguy at 20:55, 28 June 2006

2006-06-28T20:55:11Z

Show changes

← Older revision		Revision as of 02:55, 12 December 2006
Line 35:		Line 35:
	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 and shift quality, and (on some newer cars) also allows semi-[[Automatic transmission\|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.		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 and shift quality, and (on some newer cars) also allows semi-[[Automatic transmission\|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 transmission\|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]].		[[ZF\|ZF Friedrichshafen AG]] and [[BMW]] were responsible for introducing the first five-speed [[Automatic transmission\|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]].

	== [[Automatic transmission\|Automatic]] Transmission Models ==		== [[Automatic transmission\|Automatic]] Transmission Models ==