Abstract: A hydraulic system may include an electrohydraulic control valve disposed in fluid communication between a source of pressured fluid and a hydraulic actuator. The hydraulic system may be controlled to correct for offset errors between a target actuator pressure and a current actuator pressure output from the control valve, without amplifying pressure oscillations in the fluid between the control valve and the hydraulic actuator.

Abstract: A hydraulic system may include an electrohydraulic control valve disposed in fluid communication between a source of pressured fluid and a hydraulic actuator. The hydraulic system may be controlled to correct for offset errors between a target actuator pressure and a current actuator pressure output from the control valve, without amplifying pressure oscillations in the fluid between the control valve and the hydraulic actuator.

Abstract: A propulsion system, control system, and method use model predictive control systems to generate a plurality of sets of possible command values and determine a cost for each set of possible command values. The set of possible command values that has the lowest cost is determined and defined as a selected set of command values. In some circumstances, the MPC-determined command value may be replaced by another transmission ratio command based on override inputs. Minimum and maximum transmission ratios are determined based on the override inputs, and a constrained (or arbitrated) transmission ratio is determined therefrom. The constrained or arbitrated transmission ratio is used to determine whether to apply an MPC-determined transmission ratio or a transmission ratio based on the arbitrated transmission ratio to determine an ultimate commanded transmission ratio. Pressure(s) are commanded to a transmission pulley assembly, which is configured to implement the ultimate commanded transmission ratio.

Abstract: A vehicle propulsion system includes a prime mover having a prime mover output shaft, a continuously variable transmission having a variator input shaft coupled to the prime mover output shaft and having a variator output shaft, a driver torque request module in communication with a driver input and for outputting a driver torque request, an engine backbone in communication with the prime mover, and a transmission backbone in communication with the continuously variable transmission and the engine backbone in the vehicle propulsion system. The transmission backbone includes a positive torque request module that generates a positive torque request, and a positive torque request monitor that limits a torque request from the transmission backbone to the engine backbone to a maximum of a predetermined threshold.

Abstract: A propulsion system, control system, and method use model predictive control systems to generate a plurality of sets of possible command values and determine a cost for each set of possible command values. The set of possible command values that has the lowest cost is determined and defined as a selected set of command values. In some circumstances, the MPC-determined command value may be replaced by another transmission ratio command based on override inputs. Minimum and maximum transmission ratios are determined based on the override inputs, and a constrained (or arbitrated) transmission ratio is determined therefrom. The constrained or arbitrated transmission ratio is used to determine whether to apply an MPC-determined transmission ratio or a transmission ratio based on the arbitrated transmission ratio to determine an ultimate commanded transmission ratio. Pressure(s) are commanded to a transmission pulley assembly, which is configured to implement the ultimate commanded transmission ratio.

Abstract: An apparatus for ratio control of a continuously variable transmission includes a driver commanded ratio unit outputting a signal defining a commanded ratio. A clamp control portion is in communication with the driver commanded ratio unit. The clamp control portion includes: a ratio limits and override ring selecting a ratio matching the commanded ratio from an executable functions having stored ratio code data; a screening monitor continuously receiving output from the executable functions and using an input from a vehicle speed signal to compute minimum and maximum ratio limits for the ratio selected by the ratio limits and override ring; and a ratio control execution ring in communication with the screening monitor. The ratio control execution ring calculates a range of pressures allowed for operation of both primary and secondary pulleys of the continuously variable transmission.

Abstract: A vehicle propulsion system includes a prime mover having a prime mover output shaft, a continuously variable transmission having a variator input shaft coupled to the prime mover output shaft and having a variator output shaft, a driver torque request module in communication with a driver input and for outputting a driver torque request, an engine backbone in communication with the prime mover, and a transmission backbone in communication with the continuously variable transmission and the engine backbone in the vehicle propulsion system. The transmission backbone includes a positive torque request module that generates a positive torque request, and a positive torque request monitor that limits a torque request from the transmission backbone to the engine backbone to a maximum of a predetermined threshold.

Abstract: An apparatus for ratio control of a continuously variable transmission includes a driver commanded ratio unit outputting a signal defining a commanded ratio. A clamp control portion is in communication with the driver commanded ratio unit. The clamp control portion includes: a ratio limits and override ring selecting a ratio matching the commanded ratio from an executable functions having stored ratio code data; a screening monitor continuously receiving output from the executable functions and using an input from a vehicle speed signal to compute minimum and maximum ratio limits for the ratio selected by the ratio limits and override ring; and a ratio control execution ring in communication with the screening monitor. The ratio control execution ring calculates a range of pressures allowed for operation of both primary and secondary pulleys of the continuously variable transmission.

Abstract: A variator control diagnostic system for an automobile vehicle includes a ratio error calculated by subtracting a transmission actual ratio from a commanded ratio. A first lookup table includes: an adjusted ratio error defined by adjusting the ratio error using a transmission fluid temperature value; and a rate curve compared against the adjusted ratio error to identify a lookup table output. A second lookup table provides a gross slip multiplier value based on a ratio bin torque offset value for a transmission ratio range. An adjusted error count is created by multiplying the gross slip multiplier value by the lookup table output.

Abstract: A continuously variable transmission, a control system, and a method is provided for synchronizing a clutch application state change and a continuous upshift in a motor vehicle propulsion system having a continuously variable transmission (CVT). The control system and method are configured to determine whether a continuous upshift of the CVT is impending. The continuous upshift is defined as a pulley ratio change exceeding a predetermined threshold for a predetermined pulley ratio change period. If a continuous upshift is impending, the control system and method are configured to alter a clutch engagement state after a predetermined delay period to synchronize the change in clutch engagement state with an engine speed change.

Abstract: A method and system for controlling a ratio of a continuously variable transmission coupling a prime mover to a driven member in a vehicle. The method includes determining a current ratio of the continuously variable transmission, determining a projected ratio from a first ratio path of a predetermined ratio map, calculating a gradient between the current ratio and the projected ratio, determining whether the calculated gradient satisfies a gradient constraint, setting a control ratio to the projected ratio if the calculated gradient satisfies the gradient constraint, setting a control ratio to a modified ratio if the calculated gradient does not satisfy the gradient constraint, the modified ratio being based upon a ratio that satisfies the gradient constraint, and controlling the ratio of the continuously variable transmission to the control ratio.

Abstract: A method and system for controlling a ratio of a continuously variable transmission coupling a prime mover to a driven member in a vehicle. The method includes determining a current ratio of the continuously variable transmission, determining a projected ratio from a first ratio path of a predetermined ratio map, calculating a gradient between the current ratio and the projected ratio, determining whether the calculated gradient satisfies a gradient constraint, setting a control ratio to the projected ratio if the calculated gradient satisfies the gradient constraint, setting a control ratio to a modified ratio if the calculated gradient does not satisfy the gradient constraint, the modified ratio being based upon a ratio that satisfies the gradient constraint, and controlling the ratio of the continuously variable transmission to the control ratio.