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Method for improving shift quality in an automatic transmission

An automatic transmission, high-quality technology, applied in the direction of geared components, transmission control, climate sustainability, etc., can solve the problems that do not necessarily improve the shifting experience and affect the drivability of the vehicle, so as to improve the overall shifting experience , excellent shifting quality, and the effect of reducing initial stutter and undershoot

Inactive Publication Date: 2011-07-27
GM GLOBAL TECH OPERATIONS LLC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0012] Increased Torque Converter Clutch (TCC) slip: This method utilizes the slip between engine and turbine speeds to filter driveline shocks, but it has serious disadvantages as it affects vehicle drivability, shift dynamics and Fuel consumption
Also, testing proved that this move does not necessarily improve the shifting experience

Method used

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  • Method for improving shift quality in an automatic transmission
  • Method for improving shift quality in an automatic transmission
  • Method for improving shift quality in an automatic transmission

Examples

Experimental program
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Embodiment Construction

[0030] figure 1 Shows problems with the beginning and end experience as described above: strong vehicle acceleration disturbances at off-going clutch emptying and firm synchronization when upshifting from second to third gear. The acceleration in g is measured by longitudinal accelerometers fixed in the vehicle. After the pedal is released, an upshift command is issued (accompanying the accelerator position signal). Due to this throttle position change, the engine torque level is suddenly reduced, causing poor control at the start of the shift.

[0031] Ongoing clutch pressure and offgoing clutch pressure (both in kPa) are shown as a function of time: during a coast upshift, the 'offgoing' clutch is disengaged at the start of the shift and the 'oncoming' clutch Used at synchronization points. Mistiming of sync points and / or overcapacity of the "oncoming" clutch triggers the experience at the end of the shift.

[0032] Such as figure 2 and 3 It is shown that two positive...

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Abstract

The present invention concerns a method for improving shift quality in an automatic transmission. In many automatic transmissions, the shift quality during lift foot upshifts is unsatisfying. Generally, two types of complaints concering shift quality are known: harsh feel right after the shift order, bump at the synchronization of the shift. In order to provide an automatic transmission which overcomes these two problems, the invention proposes that a first and a second positive torque requests are initiated on upshift coasts. This measure improves the global shift feel by controlling the engine toque level at shift order and at synchronization: the engine torque level at the beginning of the gear shift is smoothly decreased to reduce the initial bump and is controlled at the synchronization to reduce the amplitude of underlap when the clutch capacity is rising.

Description

technical field [0001] The invention relates to a method for improving the quality of shifting in an automatic transmission. It also relates to an automatic transmission. Background technique [0002] In many automatic transmissions, shifting during an off-throttle upshift is unsatisfactory. Overall, two complaints about shift quality are known: [0003] Unpleasant feeling immediately following a shift command [0004] Frustration when shifting synchronously [0005] The present invention therefore seeks to provide an automatic transmission which overcomes both of these problems. [0006] According to the present invention, this is accomplished by generating first and second positive torque requests when upshifting during coast conditions. [0007] This measure improves both the initial shift experience and the experience at the end of the shift. [0008] With regard to the initial shift experience, the present invention is based on the assumption that the main causes ...

Claims

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Application Information

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IPC IPC(8): F16H61/04F16H63/50
CPCB60W10/115B60W2710/0666B60W10/06F16H2061/0496F16H2059/186B60W10/026F16H61/0437F16H63/502F16H2306/42B60W30/19Y10T74/20018Y02T10/60F16H61/04
Inventor 戴维.W.赖特菲利普.拉梅特摩根.波斯蒂克
Owner GM GLOBAL TECH OPERATIONS LLC
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