Process for the gear change of the automatic transmission of motor vehicles controlled with an electrohydraulic valve system
US4896565A · kind A · utility
Inventors
Key dates
| Filing date | Apr 28, 1988 |
| Grant date | Jan 30, 1990 |
| Priority date | — |
| Expiry date | Apr 28, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S477/904
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A process for controlling an automatic transmission wherein engine speed and output speed are measured and the slip conditions are derived therefrom. When conditions of downshift occur, as determined by excessively high slip and/or excessively low speed, the conditions existing at the moment of downshift are evaluated, and a comparative slip signal is derived and saved. This signal is employed as reference relating to the momentary slip conditions of the vehicle for use in determining the proper moment for a subsequent upshift. Thus, conditions for an upshift, following a particular downshift, are modified as a function of the circumstances requiring the downshift (e.g. normal deceleration, overtaking another vehicle, ascending a hill). Procedures are also included for enabling engagement of a friction clutch, for bypassing the torque converter of the transmission, under certain conditions in advance of an upshift.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.