Abstract: An on demand vehicle drive system monitors vehicle performance and operating conditions and controls torque delivery to the vehicle wheels. The system includes a plurality of speed and position sensors, a transfer case having primary and secondary output shafts driving primary and secondary drive shafts, differentials and axles and a microcontroller. The sensors include a vehicle speed sensor, a pair of primary and secondary drive shaft speed sensors, and brake and driveline status sensors. The transfer case includes a modulating electromagnetic clutch comprising a primary, cone clutch assembly which functions as a pilot device to actuate a secondary, disc pack clutch assembly. The electromagnetic clutch is controlled by the microcontroller which is incrementally engaged to transfer torque from the primary output shaft to the secondary output shaft. When the speed of either the front or the rear drive shaft overruns, i.e.

Abstract: An on demand vehicle drive system monitors vehicle performance and operating conditions and controls torque delivery to the vehicle wheels. The system includes a plurality of speed and position sensors, a transfer case having primary and secondary output shafts driving primary and secondary axles and a microcontroller. The sensors include a vehicle speed sensor, a pair of primary and secondary drive shaft speed sensors, and brake and driveline status sensors. The transfer case includes a modulating electromagnetic clutch controlled by the microcontroller which is incrementally engaged to transfer torque from the primary output shaft to the secondary output shaft. When the speed of either the front or the rear drive shafts overruns, i.e., exceeds, the speed of the other drive shaft by a predetermined value related to the vehicle speed, indicating that wheel slip is present, clutch current is incrementally increased to increase clutch engagement and torque transfer to the secondary axle.

Abstract: An on demand vehicle drive system monitors vehicle performance and operating conditions and controls torque delivery to the vehicle wheels. The system includes a plurality of speed and position sensors, a transfer case having primary and secondary output shafts driving primary and secondary axles and a microcontroller. The sensors include a vehicle speed sensor, a pair of primary and secondary drive shaft speed sensors, and brake and driveline status sensors. The transfer case includes a modulating electromagnetic clutch controlled by the microcontroller which is incrementally engaged to transfer torque from the primary output shaft to the secondary output shaft. When the speed of either the front or the rear drive shafts overruns, i.e., exceeds, the speed of the other drive shaft by a predetermined value related to the vehicle speed, indicating that wheel slip is present, clutch current is incrementally increased to increase clutch engagement and torque transfer to the secondary axle.

Abstract: A clutch cooling system for cooling a clutch used in combination with a continuously variable transmission including a pressure controlled spool valve having a housing defining a chamber, a spool movably mounted by a spring within the chamber, and a notch defined by the housing such that as the leading edge of the spool aligns with the notch a variable orifice is formed; a pressure controller means for adjusting the pressure applied to the remote end of the spool such that as the pressure applied to the remote end is reduced the spring decompresses causing the spool to traverse the housing and further causing the leading edge of the spool to pass along the notch thereby increasing the size of the variable orifice; a slot located within the spool that allows for minimum cooling flow when the spool valve variable orifice is closed; a cooling fluid feed line and a clutch cooling line extending from the chamber such that cooling fluid can flow from the cooling fluid feed line, into the chamber, through the orific

Abstract: A system and several strategies for controlling a continuously variable transmission with an improved secondary servo arrangement in order to efficiently provide sufficient clamping forces under high torque conditions. The valving means allowing for the relative movement of the second variable pulley's movable sheave includes a valving arrangement operative to regulate the secondary apply pressure at or below the hydraulic source pressure and distinct from the primary line pressure. Control signals are developed to prevent belt slip and to efficiently launch a vehicle, maintain the necessary primary to secondary clamping force ratio in overdrive conditions, and avoid overpressurization of the secondary servo for many vehicle operating conditions.

Abstract: A camshaft (26) has a vane (60) secured to an end thereof for non-oscillag rotation therewith. The camshaft also carries a sprocket (32) which can rotate with the camshaft but which is oscillatable with the camshaft. The vane has opposed lobes (60a, 60b) which are received in opposed recesses (32a, 32b), respectively, of the sprocket. The recesses have greater circumferential extent than the lobes to permit the vane and sprocket to oscillate with respect to one another, and thereby permit the camshaft to change in phase relative to a crankshaft whose phase relative to the sprocket is fixed by virtue of a chain drive extending therebetween.

Abstract: New methods for controlling an automotive continuously variable transmission (CVT) during downshifting such that chain-belt slippage will not occur. The relationship between the primary and secondary sheave forces is used to predict and control the primary force so that the primary clamping force is sufficient to prevent slippage.

Abstract: A solenoid operated hydraulic control valve system including a solenoid operated valve having a specially ported spool valve to statically balance spool forces in the opened and closed positions.

Abstract: A control system for a full time four wheel drive vehicle having a transfer case including a planetary gear differential and an electromagnetically actuated clutch assembly for biasing torque between the front and rear drive wheels in response to signals from the control system. The control system includes apparatus for detecting wheel slip and a device, responsive to the detection of wheel slip for calculating a maximum torque level to be established by the clutch assembly as a function of the total torque delivered to the transfer case and for programming clutch torque application over a predetermined time period and in a manner biasing torque through the differential to eliminate wheel slip.

Abstract: A solenoid operated hydraulic control valve which has a specially ported spool valve to statically balance spool force in the opened and closed positions, and a specially designed solenoid operator which includes very small ratios of gaps to cross-sectional areas for the working and non-working gaps between the armature and stator.

Abstract: A control system for a vehicle drive train includes a controller which is responsive to a throttle signal from a throttle position sensor and which controls a clutch unit to control speed and acceleration and to obtain optimum driver "feel". The system is responsive to advancing movement of a throttle to a more open position to efficiently utilize rotating energy of engine parts for more rapid vehicle acceleration.

Abstract: An adaptive clutch torque capacity control for an automotive vehicle clutch utilizing a dual area apply piston for engagement of the clutch plate for accurate control over a larger than normal torque range. The use of two piston areas allows one area to be controlled in a "coarse" fashion, while the other piston area, which is generally a small area, provides a "vernier" or fine adjustment control. The small area piston is controlled by an electronic closed loop for fine adjustment of any errors occurring in the "coarse" control.

Abstract: A clutch control system provides and regulates pressure at a clutch for transmitting torque from an engine to a drive train through a continuously variable transmission. A positive torque value is determined for each throttle setting and provided as a pressure input signal. Engine speed is monitored through a closed loop feedback system to provide an error signal to the desired pressure setting. A pressure control loop monitors pressure at the clutch through a closed loop feedback system to maintain the pressure at the clutch at a desired level. Filtering is provided in the torque and engine speed loops to provide for a more realistic response to driver demand. Incorporation of belt ratio factor in the engine speed control loop further provides for consistent and accurate response to driver demand variations at differing transmission drive levels. Overall line pressure within the associated hydraulic system further controls a proportional gain in the pressure control loop to provide appropriate response.

Abstract: An adaptive control system regulates operation of a mechanical seal assembly by reacting dynamically to changes in seal operating conditions to provide minimal wear with minimal fluid leakage. The disclosed "self-learning" method adapts automatically to arbitrary changes in fluid medium temperature and pressure, as well as shaft rotation speed, by detecting a limit cycle type oscillation of a seal-related variable, such as temperature of a seal face and/or fluid temperature. This variable is monitored via a microcomputer-based system which identifies these abrupt oscillations or spikes. The control algorithm selects a particular displacement of an actuator to modify the seal face deflection to the optimal value, and in this way attains maximum seal life while minimizing leakage.

Abstract: A clutch control system for a continuously variable transmission includes a mode determination system which samples input signals including position of the neutral-drive selector, driver demand, engine speed, vehicle speed, and clutch input speed. From these signals the operating mode is determined and the clutch control system operating mode is set. In starting the vehicle, a minor pressure feedback loop and a major engine speed feedback loop are used. When the clutch is locked up, these control loops are not employed in regulating the vehicle operation.

Abstract: A control system for a power shifted transmission includes an electrical signal processing system, incorporating a digital processor, which provides output signals to regulate operation of the directional clutch and the range clutches through a plurality of spool valves. A hydraulic stabilizer is connected to a common line supplying the directional clutch, to provide a predetermined amount of fluid with each change in direction, with the remainder of the fluid being provided through a forward-reverse modulating valve. A neutral bleed valve is connected to reduce the measured amount of fluid in the stabilizer when the clutch is being shifted from the neutral position, instead of a full directional change. To improve range shifts, the directional clutch is slipped while the range change is made, and the directional clutch is then re-applied. A horsepower indicator provides the vehicle operator with an instantaneous indication of the vehicle operating efficiency.

Abstract: The disclosed control system regulates changes of gear ratio in an automatic transmission for a vehicle. A supervisory control arrangement monitors operator input commands through the shift range selector lever, and receives a desired-ratio command either from a shift point computer or from a manual gear shift selector. When the supervisory control arrangement determines that the desired-ratio signal differs from the actual ratio, the monitoring function is interrupted and a shift-initiate command is provided. This command is utilized to assign certain components for use in a shift quality control arrangement, for effecting the controlled ratio change. A torque output signal from the vehicle drive line is used in conjunction with the shift quality control arrangement. After the shift is completed, the previously assigned components are released and the supervisory control arrangement resumes the monitoring of the desired ratio as contrasted to the actual gear ratio.

Abstract: A control system for a power shifted transmission with a hydraulic actuated friction clutch incorporating hydraulic valves controlled by an electronic system responsive to a torque signal from an input or output shaft in the transmission, and including a torque level controlled by a computer stage in the electronic control.

Abstract: A control system to change gear ratio in an automatic transmission 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 pair of control valves, to vary the pressure applied to a friction element by each control valve. 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 system computes an output torque ramp when a downshift is called for by the shift point computer and uses controllers which react oppositely to control engagement of a clutch and brake in response to error signals of torque output compared to a desired ramp to produce a proper shift.