A control device for an automatic transmission is provided, which includes a friction engagement element, and a processor configured to execute gear change control logic configured to control a gear change operation by supplying and discharging hydraulic fluid for forming a gear stage to/from the friction engagement element, and lubricant supply control logic configured to control to switching operation of a supply amount of lubricant to the friction engagement element according to an operating state of a vehicle. The processor controls the gear change operation and the switching operation to not overlap with one another.

A method for operating a drive train having a power generator, a mechanical power transmission device, and a power receiver wherein the power transmission device is monitored to detect mechanical damage and/or the development of mechanical damage to the power transmission device, wherein detected damage and/or detected damage development is localized and the power generator, the power transmission device, and/or the power receiver are/is controlled such that a mechanical load at the localized damage location and/or damage development location is selectively reduced. A program product including program code sections with which such a method is feasible when the program product is executed on a programmable controller, a computer, or other programmable device.

A vehicle includes an engine, a continuously variable transmission including an endless belt to output a power from the engine, and a transmission to which the power from the continuously variable transmission is transmitted. If the vehicle travel speed is not smaller than a first threshold value and an accelerator opening degree is not smaller than a second threshold value, a controller determines that the continuously variable transmission is being used in a belt high-load situation. If a travel distance in the belt high-load situation is not smaller than a third threshold value, the controller determines that the endless belt is deteriorated or deterioration thereof is in an advanced stage, and a deterioration message about the endless belt is displayed on a display based on an instruction from the controller. A situation in which a speed changing ratio of the continuously variable transmission is not greater than a fourth threshold value may be determined as the belt high-load situation.

A clutch includes a clutch disk that rotates by receiving motive power from an engine and a clutch plate switched between an engaged state in which it is engaged with the clutch disk and a disengaged state in which it is not engaged with the clutch disk. A controller calculates a coefficient of friction μ between the clutch disk and the clutch plate based on a time period Δt elapsed from a first time point when the number of relative rotations of the clutch disk and the clutch plate attains to a first number of rotations to a second time point when a second number of rotations smaller than the first number of rotations is attained, in a state in which the clutch disk rotates while transfer of motive power from the engine to the clutch disk is cut off and in the engaged state.

A drive transmission device is provided with a drive pulley driven by a motor, a driven pulley in which a bulging part crowned in a shape bulging outward in the radial direction is formed over the entire circumference of the outer peripheral surface, a belt wound around the drive pulley and the driven pulley, and a first measurement unit for measuring rotation unevenness of the drive pulley. The drive pulley has a uniform diameter in the axial direction which is a smaller diameter than that of the driven pulley. The belt is bent and deformed along the bulging part of the driven pulley so that the axial center portion is expanded outward the axial end portion. The axial end of the belt contacts the outer peripheral surface of the drive pulley, but does not contact the outer peripheral surface of the driven pulley.

A method for determining belt wear in a belt drive, wherein the belt is loaded with a defined torque and the rotation angle of a pulley is determined.

A diagnostic system of a vehicle for diagnosing a drive belt of a continuously variable transmission. A diagnostic circuit detects or predicts a fault of the drive belt based on an operating parameter received from a sensor associated with the vehicle during a predetermined diagnostic period.

A method for monitoring a belt drive with a power-transmitting endless drive belt which is in the form of a traction belt and wraps around the drive and driven pulleys circumferentially over a partial circumference in each case, wherein the belt has at least one first marking and a first sensor element assigned to the belt is provided and is used to detect the passage of the first marking during the belt revolution, wherein the first sensor element has devices for outputting a signal S.sub.R dependent on the detection of the first marking, wherein the rotor of the drive motor has a second marking and a second sensor element which is provided with corresponding electronic devices and is assigned to the drive motor is provided, wherein, while the rotor is rotating, the passage of the second marking is detected by the second sensor element and a signal S.sub.M dependent on the detection of the second marking is output, wherein, furthermore, a computing unit provided with memories and processors for processing the signals S.sub.R and S.sub.M is provided, wherein a temporal or local correlation of the occurrence of the signals S.sub.R and S.sub.M is calculated in the computing unit when the drive belt is new and is stored as a reference value, and the associated signals S.sub.R and S.sub.M are then repeatedly determined for further specified belt revolutions or periods of time and their current temporal or local correlation of the occurrence is compared with the reference value.

A belt-type continuously variable transmission includes an actual gear ratio calculation unit for calculating an actual gear ratio based on the rotation speed of a drive pulley and the rotation speed of a driven pulley, a reference gear ratio calculation unit for calculating a reference gear ratio by modifying the actual gear ratio based on an input torque and a driven pulley hydraulic pressure, and a condition determination unit for, in a case where the target gear ratio is an overdrive gear ratio, determining that at least part of rings of a belt is missing when the reference gear ratio is greater than or equal to a predetermined gear ratio and a drive pulley hydraulic pressure is greater than or equal to a predetermined hydraulic pressure.

To detect the occurrence of slippage, a transmission health monitor integrates speed measurements for an engine shaft and a transmission shaft to determine a number of revolutions for each shaft. The monitor then uses a ratio of the revolutions adjusted for a transmission gear ratio to determine whether slippage has occurred. Based on the slippage, the monitor can determine a cumulative amount of wear on a clutch for each gear and track the rate of change of slippage over time to determine a rate at which wear is occurring. The monitor can also correlate slippage calculations with torque measurements to identify operating conditions at which slippage is occurring. The monitor uses the cumulative amount of slippage, the rate of change of slippage, and the operating conditions at which slippage is occurring to estimate a remaining lifespan for a clutch or indicate that a clutch should be repaired or replaced.