Hydraulic clutch pressure control for an electronically controlled transmission

Patent · Tue Dec 16 04:00:00 EST 1986

OSTI ID:6859389

Person, D W; Pierce, S L; Liang, P

A system is described for changing drive ratios in an automatic transmission having gear elements for producing multiple drive ratios comprising: a source of pressurized hydraulic fluid; multiple clutches for connecting and holding elements of the gearing, whereby certain drive ratios are produced by selectively pressurizing pairs of the clutches and venting the unselected clutches, each clutch pair being uniquely associated with one drive ratio; actuator valve means for selectively, concurrently pressurizing pairs of the clutches and for venting unselected clutches; feedline valve means connected to the pressure source for comparing the sum of the pressures in the clutches to a predetermined pressure. It also hydraulically connects the pressure source to the actuator valve means if the pressure sum is equal to or less than the predetermined pressure, disconnects the pressure source from the actuator valve means and connects the pressure source to the clutches whose engagement produces a predetermined drive ratio; and coast control valve means for directing pressurized fluid to a clutch that is not a member of a clutch pair selectively and concurrently pressurized through operation of the actuator valve means and for venting the clutch.

• Assignee: Ford Motor Co., Dearborn, MI
• Patent Number(s): US 4628771
• OSTI ID: 6859389
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330602* -- Vehicle Design Factors-- Engine-Transmission Matching
ACTUATORS
CONTROL
CONTROL EQUIPMENT
CONTROL SYSTEMS
EQUIPMENT
FEEDBACK
FLOW REGULATORS
FLUIDS
GEARS
HYDRAULIC CONTROL DEVICES
HYDRAULIC FLUIDS
MACHINE PARTS
MECHANICAL TRANSMISSIONS
PRESSURE CONTROL
PRESSURIZING
VALVES
VEHICLES
WORKING FLUIDS