Dual Clutch Transmissions - Wet vs. Dry
Here is a brief comparison of DCT systems with Wet and Dry Clutches.
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Wet Clutch |
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Dry Clutch |
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Clutches are cooled and lubricated by oil |
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Clutches are not lubricated |
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May have a combined (single) sump for the clutch and gearbox, or separate sumps for the clutch and gearbox |
Single sump for the gearbox |
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Customised DCT fluid is needed for the clutches in a single sump application – this needs to provide for both the frictional requirements of the clutches and the load-carrying and synchromesh performance of the gearbox |
No lubricant is required for the clutches |
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Gearbox lubricated either by DCT fluid (in single sump application) or MTF (in separate sump application) |
Gearbox lubricated with MTF |
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Can be used in higher, as well as lower, torque applications due to the cooling effect of the lubricant on the clutches under high loads |
Restricted to lower torque applications due to the lack of oil to cool the clutches under high loads |
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Incurs parasitic losses when pumping the DCT fluid |
Improved efficiencies due to reduced parasitic losses for fluid pumping, reduced weight and fluid quantity |
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Examples: |
Examples: |
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Single Sump |
Volkswagen DQ250 |
Volkswagen DQ200 |
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Separate Sump |
Audi DL501, Porsche PDK |
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