Method and apparatus for a transmission control system
US4031782A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 27, 1976 |
| Grant date | Jun 28, 1977 |
| Priority date | — |
| Expiry date | Feb 27, 1996 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16H2061/0255
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A control system used to change the gear ratio in a gear set regulated by a change-gear signal from a control unit is disclosed. A transducer provides an output torque signal which is compared to other signals for initiating the gear change. In another arrangement, an automatic transmission changes a gear ratio when engine torque is transferred from one member to another member of a three member planetary gear set. This transfer is accomplished through friction elements engaged by hydraulic pressure. A closed loop electrical circuit is completed between a transducer, which provides an electrical signal related to the output torque of the transmission, and a control valve, to vary the control valve pressure. A circuit for computing reaction torque is coupled between the transducer and a logic control circuit, which provides logic command signals for controlling operation of components in the closed loop circuit. The closed loop circuit includes a pulse width modulation circuit for regulating the control valve operation, and a feed-forward circuit to minimize the delay in the control valve portion of the system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.