Mercedes-Benz 9G-Tronic transmission
Articles structure: headlines gearset concept
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The driver can change gears either using the steering-wheel shift paddles or conventionally the selector lever. The new Race Start Function is a launch control system that enables maximum acceleration while ensuring optimum traction of the driven wheels. |
The driver can change gears either using the steering-wheel shift paddles or conventionally the selector lever. The new Race Start Function is a launch control system that enables maximum acceleration while ensuring optimum traction of the driven wheels. |
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== Gearset concept == |
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=== Main objectives === |
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The main objectives in replacing the previous 7G-Tronic model were to improve fuel consumption by adding gears and increasing the gear span, while at the same time reducing manufacturing costs. |
The main objectives in replacing the previous 7G-Tronic model were to improve fuel consumption by adding gears and increasing the gear span, while at the same time reducing manufacturing costs. |
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The wide gear span{{efn|name="Version"|First version with a gear ratio span wider than 9.1:1.{{cite web| url=http://documents.epfl.ch/users/f/fr/froulet/www/Mechanics/2013_09_002_002_en.pdf| title=Automatic Transmission 9G-Tronic · 725.0 · System Description| publisher=documents.epfl.ch| date= September 2013| accessdate=2020-01-16}} (PDF) Was replaced by a slightly more narrowly stepped 2nd version with the introduction of the [[Mercedes-Benz E-Class (W213)]] series in 2016 without announcement}} allows the engine speed level to be lowered (downspeeding), which is a decisive factor in improving energy efficiency and thus reducing fuel consumption by 6.5 %. In addition, the lower engine speed level improves the noise-vibration-harshness comfort and the exterior noise is reduced by up to 4 dB(A). A speed of 120 km/h is reached in the Mercedes-Benz E 350 BlueTEC in 9th gear at an engine speed of approx. 1350 rpm.{{cite web| url=https://www.sueddeutsche.de/auto/mercedes-e-350-bluetec-im-test-neun-gaenge-menue-1.1977043| title=Thomas Harloff: ''Neun-Gänge-Menü''| date=2014-05-27}} Unsurpassed ratio span among [[longitudinal engine|longitudinal]] [[automatic transmission]]s for passenger [[car]]s.{{efn|By the end of 2024}} |
The wide gear span{{efn|name="Version"|First version with a gear ratio span wider than 9.1:1.{{cite web| url=http://documents.epfl.ch/users/f/fr/froulet/www/Mechanics/2013_09_002_002_en.pdf| title=Automatic Transmission 9G-Tronic · 725.0 · System Description| publisher=documents.epfl.ch| date= September 2013| accessdate=2020-01-16}} (PDF) Was replaced by a slightly more narrowly stepped 2nd version with the introduction of the [[Mercedes-Benz E-Class (W213)]] series in 2016 without announcement}} allows the engine speed level to be lowered (downspeeding), which is a decisive factor in improving energy efficiency and thus reducing fuel consumption by 6.5 %. In addition, the lower engine speed level improves the noise-vibration-harshness comfort and the exterior noise is reduced by up to 4 dB(A). A speed of 120 km/h is reached in the Mercedes-Benz E 350 BlueTEC in 9th gear at an engine speed of approx. 1350 rpm.{{cite web| url=https://www.sueddeutsche.de/auto/mercedes-e-350-bluetec-im-test-neun-gaenge-menue-1.1977043| title=Thomas Harloff: ''Neun-Gänge-Menü''| date=2014-05-27}} Unsurpassed ratio span among [[longitudinal engine|longitudinal]] [[automatic transmission]]s for passenger [[car]]s.{{efn|By the end of 2024}} |
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==== Extent ==== |
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As the design of the predecessor was significantly more complex than that of the direct competitor 6HP and even the new 8HP model from ZF with one more gear, the specification sheet also stipulate that at least one shift element must be omitted. This was achieved thanks to high-speed computer-aided design and has resulted in a globally patented gearset concept that requires the same installation space as the previous model and is also {{convert|1|kg|lb|1|abbr=on|lk=on}} lighter. In the process, 85 billion gearset concepts were examined.{{cite web| url=https://media.mercedes-benz.com/article/d98f5455-30a3-44c9-9eb6-f2e9f9709aa5/(lightbox:document/d4e96d1e-c3e9-4568-a6cc-4ce277704ee8)| title=Developed for in-house drive systems: The best out of 85 billion possibilities| date=2014-03-06| accessdate=2024-10-29}} Additionally, the unit brings the ability to shift in a non-sequential manner – going from gear 9 to gear 4 in extreme situations simply by changing one shift element (actuating brake C and releasing brake A). |
As the design of the predecessor was significantly more complex than that of the direct competitor 6HP and even the new 8HP model from ZF with one more gear, the specification sheet also stipulate that at least one shift element must be omitted. This was achieved thanks to high-speed computer-aided design and has resulted in a globally patented gearset concept that requires the same installation space as the previous model and is also {{convert|1|kg|lb|1|abbr=on|lk=on}} lighter. In the process, 85 billion gearset concepts were examined.{{cite web| url=https://media.mercedes-benz.com/article/d98f5455-30a3-44c9-9eb6-f2e9f9709aa5/(lightbox:document/d4e96d1e-c3e9-4568-a6cc-4ce277704ee8)| title=Developed for in-house drive systems: The best out of 85 billion possibilities| date=2014-03-06| accessdate=2024-10-29}} Additionally, the unit brings the ability to shift in a non-sequential manner – going from gear 9 to gear 4 in extreme situations simply by changing one shift element (actuating brake C and releasing brake A). |
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After the 5G- and 7G-Tronic, this transmission is the 3rd generation in which in-line [[epicyclic gearing]] have been combined with parallel [[epicyclic gearing]]. The resulting progress is reflected in an even better ratio between the number of gears and the number of components used compared to all layouts previously used by Mercedes-Benz. |
After the 5G- and 7G-Tronic, this transmission is the 3rd generation in which in-line [[epicyclic gearing]] have been combined with parallel [[epicyclic gearing]]. The resulting progress is reflected in an even better ratio between the number of gears and the number of components used compared to all layouts previously used by Mercedes-Benz. |
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=== Quality === |
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The ratios of the 9 gears are better distributed in all versions than in the direct competitors [[ZF 8HP transmission|8HP]] from ZF and much better than in the 10-speed transmissions from [[Ford–GM 10-speed automatic transmission|Ford/GM]] and Aisin/Toyota. The only noticeable weaknesses are the relatively small step between 5th and 6th gear and the too small one between 6th and 7th gear. These cannot be eliminated without affecting all other gears and thus impairing gear steps. On the other hand, these weaknesses are not overly significant. |
The ratios of the 9 gears are better distributed in all versions than in the direct competitors [[ZF 8HP transmission|8HP]] from ZF and much better than in the 10-speed transmissions from [[Ford–GM 10-speed automatic transmission|Ford/GM]] and Aisin/Toyota. The only noticeable weaknesses are the relatively small step between 5th and 6th gear and the too small one between 6th and 7th gear. These cannot be eliminated without affecting all other gears and thus impairing gear steps. On the other hand, these weaknesses are not overly significant. |
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