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A method for controlling a downshift in an automatic transmission

一种自动变速器、降档的技术，应用在带有齿的元件、传动装置控制、皮带/链条/齿轮等方向，能够解决沉闷金属声、传动系冲击、转矩扰动等问题

Inactive Publication Date: 2009-06-03
FORD GLOBAL TECH LLC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Torque reversal causes staggering of driveline shocks, creating torque disturbances and clunks

Method used

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  • A method for controlling a downshift in an automatic transmission
  • A method for controlling a downshift in an automatic transmission
  • A method for controlling a downshift in an automatic transmission

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0017] Referring now to the drawings, there is shown in FIG. 1 a dynamic layout diagram of an automatic transmission 10 . The torque converter includes a bladed radial impeller 12 , a bladed vortex impeller 16 , and a bladed stator impeller 18 connected to a crankshaft 14 of the internal combustion engine. The radial impeller, stator impeller and vortex impeller form an annular fluid flow path whereby the radial impeller 12 is hydrodynamically connected to the vortex impeller 16 . Although free impeller motion in the opposite direction is permitted, the stator impeller 18 is rotatably supported on a stationary stator sleeve shaft 20 to which an overspeed brake 22 anchors the stator to prevent the stator from moving in contact with the radial impeller. The direction of rotation is the opposite of the direction of rotation.

[0018] The torque converter includes a bypass clutch 24 disposed within the torque converter 26 . The scroll and radial impellers are mechanically connec...

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PUM

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Abstract

A method for controlling a coast down downshift that is produced in an automatic transmission by disengaging an off-going control element and engaging an oncoming control element, including the steps of determining a first desired pressure magnitude of the off-going control element and a first desired pressure magnitude of the oncoming control element, executing the current downshift using said first desired pressure magnitudes, determining during execution of the current downshift corrections of said first desired pressure magnitudes that occur during the current downshift, determining a second desired pressure magnitude of the off-going control element and a second desired pressure magnitude of the oncoming control element, using said corrections and the second desired pressure magnitude to determine a subsequent desired pressure magnitude of the off-going control element and a subsequent desired pressure magnitude of the oncoming control element, and executing a downshift using said subsequent desired pressure magnitudes.

Description

technical field [0001] The present invention relates generally to a multi-speed stepped automatic transmission for a motor vehicle, and more particularly to controlling coast downshifts performed by the transmission. Background technique [0002] During an automatic transmission coast downshift, where shifts occur between individual gear ratios, jerk transitions occur when the torque converter turbine and the engine (or impeller torque converter) accelerate interleaved at excessive speeds . This impact transition excites components in the transmission and drivetrain, causing the driver and passengers to experience a clunk and clack. In some cases, the shocks are staggered back and forth, and the occupant is subjected to both a very long shift and a double clunk. [0003] The technical reason for the clunk during the coast downshift sequence is that the components that are about to be synchronized, such as the brakes including the bands and drums, gain maximum torque relati...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B60W10/02B60W10/10B60W10/06
CPCF16H2061/064F16H2342/04F16H2306/44F16H2306/52F16H61/061F16H61/065F16H61/10
Inventor 马克·A·史密斯道格拉斯·R·塞西尔迈克尔·塔兰特文斯·P·拉沃伊
Owner FORD GLOBAL TECH LLC