摘要:
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. When wheel slip is reduced below the predetermined value the current to the clutch is incrementally reduced. The method of operating such a system is also described.
摘要:
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. When wheel slip is reduced below the predetermined value the current to the clutch is incrementally reduced. The method of operating such a system is also described.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
An electronic controller for a variable ratio transmission and an electronically controllable variable ratio transmission including a variator or other CVT are described herein. The electronic controller can be configured to receive input signals indicative of parameters associated with an engine coupled to the transmission. The electronic controller can also receive one or more control inputs. The electronic controller can determine an active range and an active variator mode based on the input signals and control inputs. The electronic controller can control a final drive ratio of the variable ratio transmission by controlling one or more electronic solenoids that control the ratios of one or more portions of the variable ratio transmission.
摘要:
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.
摘要:
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. Phase compensation and integral dynamic phase factors in the pressure control loop further guarantee a zero level steady state error signal and the generation of accurate control over the pressure control valve.
摘要:
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. One circuit controls all the upshifts, whether 1-2, 2-3, or 3-4, and one other circuit controls all the downshifts. This assignment of certain components for each controlled ratio change, and their release so they can be re-used in subsequent ratio changes, contributes to a cost-effective trade-off between the number of circuits required in the total system and the complexity of the logic circuits actually employed.
摘要:
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.