Transmission clutch closed loop slip controller and method
First Claim
1. A system for controlling the operation of a slipping clutch for use in the transmission of a motor vehicle comprising:
- a clutch having a driving member and a driven member driveably engaged and disengaged in accordance with the magnitude of lockup clutch pressure developed in the clutch;
an electrical solenoid-operated valve means for producing hydraulic fluid flow to the clutch;
means for producing signals representing the magnitude of the speeds of the driving member and the driven member;
means for calculating a current slip across the clutch and for producing current commanded slip;
means for producing slip error duty cycle from the current commanded slip and the current calculated slip;
minor loop feedback means for producing a signal representing the magnitude of lockup clutch pressure;
means for producing a current duty cycle from the sum of the slip error duty cycle and a previously calculated duty cycle minus the minor loop feedback signal; and
means for converting the current duty cycle to a signal proportional thereto, and driving the solenoid with said proportional signal and producing lockup clutch pressure in the clutch tending to engage the driving and driven members.
2 Assignments
0 Petitions
Accused Products
Abstract
A continuously variable belt-driven transmission includes a hydraulic torque converter, a variable diameter displaceable input pulley, a variable diameter displaceable output pulley, forward and reverse planetary gearing, a differential mechanism and half shafts driven from the differential mechanism. A slipping lockup clutch is hydraulically actuated to connect and disconnect selectively the impeller and turbine of the torque converter. The radial position of the drive belt that engages the input and output pulleys is determined by selectively pressurizing and venting a cylinder to move displaceable sheaves of a pulley. Hydraulically actuated clutches are selectively engageable to produce forward drive or reverse drive from the output pulley to the differential mechanism. Various sensors produce electric signals as input to a microprocessor indicate the position of the engine throttle, the magnitude of engine speed, primary pulley speed, secondary pulley speed, converter lockup clutch pressure, belt load pressure, line pressure and the position of a PRNDL gear selector. A valve body hydraulically actuates, in accordance with the output produced by the computer, the forward clutch, the reverse clutch, the torque converter lockup clutch and the displaceable sheaves of the input pulley and output pulley. An electronic feedback system controls the slip, engagement and disengagement of the torque converter lockup clutch.
45 Citations
12 Claims
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1. A system for controlling the operation of a slipping clutch for use in the transmission of a motor vehicle comprising:
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a clutch having a driving member and a driven member driveably engaged and disengaged in accordance with the magnitude of lockup clutch pressure developed in the clutch; an electrical solenoid-operated valve means for producing hydraulic fluid flow to the clutch; means for producing signals representing the magnitude of the speeds of the driving member and the driven member; means for calculating a current slip across the clutch and for producing current commanded slip; means for producing slip error duty cycle from the current commanded slip and the current calculated slip; minor loop feedback means for producing a signal representing the magnitude of lockup clutch pressure; means for producing a current duty cycle from the sum of the slip error duty cycle and a previously calculated duty cycle minus the minor loop feedback signal; and means for converting the current duty cycle to a signal proportional thereto, and driving the solenoid with said proportional signal and producing lockup clutch pressure in the clutch tending to engage the driving and driven members. - View Dependent Claims (2, 3)
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4. A system for controlling the operation of a slipping clutch for use in the transmission of a motor vehicle comprising:
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a torque converter having an impeller and a turbine arranged in hydrodynamic driving relation and a casing for containing fluid; lockup clutch means for driveably engaging and disengaging the impeller and turbine in accordance with the relative magnitudes of a converter feed pressure and a lockup clutch pressure; an electrical solenoid-operated valve means for producing hydraulic fluid flow to the clutch; means for producing signals representing the magnitude of the speeds of the impeller and the turbine; means for calculating a current slip across the clutch and for producing a current commanded slip; means for producing slip error duty cycle from the current commanded slip and the current calculated slip; minor loop feedback means for producing a signal representing the magnitude of the lockup clutch pressure; means for producing a current duty cycle from the sum of the slip error duty cycle and a previously calculated duty cycle minus the minor loop feedback signal; and means for converting the current duty cycle to a signal proportional thereto, driving the solenoid with said proportional signal and producing the lockup clutch pressure in the clutch tending to connect the impeller and turbine. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12)
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Specification