Automatic range shift for multi-speed transmission
US5928109A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 28, 1997 |
| Grant date | Jul 27, 1999 |
| Priority date | — |
| Expiry date | Aug 28, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T74/1926
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A system for automatically effecting a range shift between high and low ranges in a multi-speed transmission includes a control that monitors the output speed of both the engine and the transmission. The ratio of the two speeds is compared to available ratios in a look-up table such that the control is constantly determining the engaged gear. In one embodiment, a driver provides an intention of the next gear to be selected to the control. Should the intended gear shift require a range shift from the engaged gear, the control actuates the range shift once the transmission has been moved to neutral. In a second embodiment, no driver intention is provided to the controller. Instead, the control compares the engine output speed to threshold values. If the threshold values predict a gear shift that would require a range shift to be effected from the currently engaged gear, then the range shift will be effected once the transmission has been moved to neutral.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.