John M Ivey

US Patent:

40317820, Jun 28, 1977

Filed:

Feb 27, 1976

Appl. No.:

5/661896

Inventors:

Alan Leonard Miller - Mount Prospect IL
John Saxon Ivey - Bloomfield Hills MI

Assignee:

Borg-Warner Corporation - Chicago IL

International Classification:

B60K 4118
G05G 2100

US Classification:

74866

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.