METHODS FOR IMPROVED POWER TRANSMISSION PERFORMANCE
Advanced methods are provided for achieving improved power transmission performance, and unique fluid compositions useful for practicing such methods are also presented. In particular a method is provided for reducing NVH in a power transmission apparatus having a friction torque transfer apparatus, such as, e.g., a shifting clutch, comprising maintaining a negative ∂μ/∂T slope, and/or a negative ∂μ/∂P slope, during engagement of the friction torque transfer apparatus.
1 . A method of suppressing NVH in a power transmission apparatus having a friction torque transfer apparatus comprising maintaining a negative ∂μ/∂T slope during engaging, slipping or modulating thereof.
2 . The method of claim 1 , wherein the friction torque transfer apparatus is selected from the group consisting of a shifting clutch, a starting clutch, a torque converter clutch, a band clutch, disk or plate clutch, and a limited slip differential clutch.
3 . The method of claim 1 , wherein the friction torque transfer apparatus comprises a shifting clutch.
4 . The method of claim 1 , wherein the transmission apparatus comprises a multi-speed transmission comprising at least a four-speed or more transmission.
5 . The method of claim 1 , wherein the transmission apparatus comprises a multi-speed transmission comprising a five-speed automatic transmission, a six-speed automatic transmission, and a seven-speed automatic transmission.
6 . The method of claim 1 , wherein the transmission apparatus comprises a dual-clutch transmission.
7 . The method of claim 1 , wherein the transmission apparatus comprises a continuously variable transmission.
8 . The method of claim 1 , wherein the negative ∂μ/∂T slope is maintained without reducing static or quasi-static friction at the clutch during the engagement.
9 . The method of claim 1 , wherein the controlled NVH includes squawk.
10 . A method of suppressing NVH in a power transmission apparatus having a friction torque transfer apparatus comprising maintaining a negative ∂μ/∂P slope during engaging, slipping or modulating thereof
11 . A power transmission apparatus comprising a friction torque transfer apparatus having a clutch surface in contact with a transmission fluid, said transmission operable to maintain a negative ∂μ/∂T slope during engaging, slipping or modulating of the friction torque transfer apparatus.
12 . The power transmission apparatus of claim 11 , wherein the friction torque transfer apparatus is selected from the group consisting of a shifting clutch, a starting clutch, a torque converter clutch, a band clutch, disk or plate clutch, and a limited slip differential clutch.
13 . The power transmission apparatus of claim 11 , wherein the friction torque transfer apparatus comprises a shifting clutch having a clutch surface in contact with a transmission fluid composition, said transmission operable to maintain a negative ∂μ/∂T slope during engagement of the shifting clutch.
14 . The transmission of claim 11 , wherein the transmission comprises a continuously variable transmission.
15 . The transmission of claim 11 , wherein the transmission comprises a dual clutch transmission.
16 . The transmission of claim 11 , wherein the transmission comprises an automatic transmission.
17 . The transmission of claim 11 , wherein the transmission comprises a manual transmission.
18 . The transmission of claim 11 , wherein the transmission comprises one or more of an electronically controlled converter clutch, a slipping torque converter, a lock-up torque converter, a starting clutch, and one or more shifting clutches.
19 . The transmission of claim 11 , wherein the transmission apparatus comprises a multi-speed transmission comprising at least a four-speed or more transmission
20 . The transmission of claim 11 , wherein the transmission comprises a belt, chain, or disk-type continuously variable transmission, a 4-speed or more automatic transmission, a manual transmission, an automated manual transmission, or a dual clutch transmission.
21 . A vehicle comprising an engine, and the transmission of claim 11 .
22 . The vehicle of claim 21 , comprising a heavy duty bus.