Electronic and hydraulic control system for automotive, automatic gear change transmissions
US3937108A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 21, 1974 |
| Grant date | Feb 10, 1976 |
| Priority date | — |
| Expiry date | Oct 21, 1994 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S477/906
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
To permit continued operation of an electronically controlled gear change transmission in case of failure of electronic control signals, at least one three-way check valve is included in the system to connect, in one mode of operation, the normal output control signals from a hydraulic control valve system to engage an operating element (such as a control clutch, control band, or the like in the automatic transmission) and, when in another position, connect hydraulic pressure to effect connection of drive power to the first gear, or reverse (as selected by a control selector) and in the absence of electrical command signals from the electronic control unit. By use of a second three-way check valve, simple interlocks to prevent shifting into reverse when the vehicle is moving forward in excess of a given speed, and to permit holding of an engaged gear in case of malfunction, can be provided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.