Abstract: A servo assembly 22 for selectively engaging a brake band 14 in an automotive vehicle is disclosed. Servo assembly 22 includes a piston 26 at least partially encased in a housing 24 and a first and second supply 111, 132 of hydraulic fluid which selectively actuate the piston to engage the brake band.

Abstract: A multiple ratio automatic transmission control system for an automotive vehicle comprising a multiple ratio gear set and a simple planetary gear set arranged in series. The control system has multiple control modes including an automatic control mode in which upshifts and downshifts between adjacent ratios are achieved by engaging and releasing friction clutches and brakes in the simple planetary gear set and in the multiple ratio gear set and wherein a manual shift control mode includes a select-shift control. Engine braking is available in each gear for both operating modes. In the select-shift manual control mode, a particular gear can be chosen by the operator for continuous single-ratio operation. The control system includes variable force solenoids that are multiplexed in combination with pressure modulator valves for achieving each operating mode.

Abstract: A method for cleaning a solenoid-operated regulator valve wherein command current applied to a solenoid actuator establishes a defined response of a valve. Cleaning current pulses applied to the solenoid establish a response that does not interfere with the effectiveness of the valve function. The pulse width, pulse amplitude, pulse direction and pulse period are determined by the degree of contamination of the valve environment.

Abstract: A control valve system for a multiple ratio transmission with a high ratio clutch and an intermediate ratio brake servo including a first solenoid operated valve that generates a control pressure for intermediate servo apply and a second solenoid operated valve that generates a control pressure for intermediate servo release and for the high clutch. The second and the first solenoid valves control the intermediate servo stroke phase and the second solenoid valve controls, either closed or open loop, the deceleration of a high clutch drum. Pressures electronically controlled by the solenoid valves are distributed to the clutch and brake servo pressure chambers by a shift valve configuration, whereby high quality upshifts and downshifts are achieved.

Abstract: A method is provided for determining the speed and direction of a rotating shaft. A rotor is connected to the shaft. The rotor includes three circumferentially spaced teeth, the first of said teeth having a first center spacing, the second of said teeth having a second center spacing different than the center spacing of the first tooth, and the third of said teeth having a third center spacing different than the center spacing of the second tooth. The centers of each of said teeth is sensed and a signal is produced in response thereto. A first time period to reach the center of the first tooth, a second time period to reach the center of the second tooth and a third time period to reach the center of the third tooth are determined, then the speed and direction of rotation of the shaft are established.

Abstract: An apparatus is provided to determine the speed and direction of a rotating shaft, including a rotor with three circumferentially spaced teeth connected to the shaft. The spacing of the center of the second rotor tooth is wider than the spacing of the center of the first tooth and the spacing of the center of the third tooth is wider than the spacing of the center of the second tooth. A sensor detects the center of each tooth and produces a signal in response thereto. The signal is received by a computer. The computer determines the speed and direction of rotation of the shaft by determining a first time period to reach the center of the first tooth, a second time period to reach the center of the second tooth and a third time period to reach the center of the third tooth.

Abstract: A shift control lever assembly for an automatic transmission is provided which includes an automatic shift mode and a manual shift mode. The lever assembly comprises a first shift lane having a plurality of positions for automatic operation of the transmission and a second shift lane adjacent the first lane for manual operation of the transmission. The second shift lane includes a first position at a first end of the second lane for selecting an upshift and a second position at a second end of the second lane for selecting a downshift. A shift lever is moveable in the first and second shift lanes. First and second switches are contacted by the shift lever concurrently upon moving of the shift lever from the first shift lane into the second shift lane to command a manual operating mode. The first switch is released by the lever when the lever is moved to the first position in the second shift lane while maintaining contact with the second switch.

Abstract: A servo for operating a brake band in an automatic transmission includes a transmission casing and servo cover defining a servo cylinder, a servo piston supported for displacement within the cylinder, first and second sealed volumes within the cylinder, a valve for connecting the fluid sump to one pressure area and for closing that connection and opening a connection to line pressure while maintaining the first pressure area connected to line pressure.