A transmission ratio controller includes circuitry including a transmission ratio calculator and a monitor. The transmission ratio calculator calculates a transmission ratio using a first transmission ratio map when a specified parameter satisfies a first condition, and using a second transmission ratio map when the specified parameter satisfies a second condition. When the specified parameter satisfies the first condition, the internal combustion engine is in a first state. When the specified parameter satisfies the second condition, the internal combustion engine is in a second state. In the first state, the monitor calculates a hypothetical transmission ratio using the second transmission ratio map based on the second state. On a condition that the transmission ratio calculated in the first state differs from the hypothetical transmission ratio by a predetermined reference value or greater, the monitor determines that the transmission ratio has a possibility of differing in accordance with the specified parameter.

A transmission ratio controller includes circuitry that includes a transmission ratio calculator calculating a request transmission ratio, a transmission ratio instructor transmitting a control signal, and an abnormality determiner. The request transmission ratio is calculated using a first transmission ratio map when a specified parameter satisfies a first condition, and a second transmission ratio map when the specified parameter satisfies a second condition. The internal combustion engine is in a first state when the specified parameter satisfies the first condition, and in a second state when the specified parameter satisfies the second condition. In the first state, the abnormality determiner calculates a hypothetical transmission ratio using the second transmission ratio map based on the second state. The abnormality determiner determines an abnormality based on a comparison of the hypothetical transmission ratio with at least one of the request transmission ratio, an instruction transmission ratio, or an actual transmission ratio.

According to the present invention, there is provided a method of reducing output torque deficits during the launch of a vehicle having a continuously variable transmission, wherein the variator has an input connected to a prime mover and an output. The method comprises the steps of determining a rate of change of ratio in the transmission, and predicting a required motor speed ratio rate of change value of the variator on the basis of: (i) the determined rate of change of ratio in the transmission, and (ii) the configuration of the transmission. The speed of the variator output is adjusted so as to achieve the required motor speed ratio rate of change value.

A transmission ratio controller includes circuitry. The circuitry includes a transmission ratio calculator configured to calculate a request transmission ratio to a transmission mechanism, a transmission ratio instructor configured to output a control signal based on the request transmission ratio, and an abnormality determiner configured to determine whether a transmission ratio of the transmission mechanism is abnormal. At least two of the request transmission ratio, an instruction transmission ratio corresponding to the control signal, or an actual transmission ratio achieved by the transmission mechanism are transmission ratios subject to comparison. The abnormality determiner is configured to determine that when a difference obtained by comparing the transmission ratios subject to comparison is greater than or equal to a predetermined specified value, the transmission ratio of the transmission mechanism is abnormal.

A position controller includes: an oil temperature acquisition unit that acquires information on an oil temperature of a hydraulic actuator; a position acquisition unit that acquires an actual value of an operation position of an object; a position control unit that calculates an operation command value for a control valve of the hydraulic actuator by closed-loop control so as to reduce a deviation between a target value of the operation position of the object and the actual value; and a gain setting unit that changes at least one gain of the closed-loop control so that sensitivity of the closed-loop control increases as the oil temperature decreases.

The control mode is switched between a first control mode configured to control the speed change pump based on an actual speed ratio being an actual speed ratio of the variator, and a second control mode configured to control the speed change pump based on an actual working pressure being an actual working pressure of the variator. In the first control mode, the actual speed ratio is calculated based on a detected value of a vehicle speed; and the speed change pump is controlled to cause the actual speed ratio to approach the target speed ratio. In the second control mode, the actual working pressure is detected and the speed change pump is controlled to cause the actual working pressure to approach a target working pressure corresponding to the target speed ratio. In a situation or a condition where the detection accuracy of the vehicle speed by the vehicle speed sensor decreases, the control mode is switched from the first control mode to the second control mode.

A control device for a continuously variable transmission performs feedback control so that an actual transmission control value becomes a target transmission control value. The control device includes a phase lead compensation unit configured to perform phase lead compensation of the feedback control, a phase delay compensation unit configured to perform phase delay compensation of the feedback control, a first peak value frequency determination unit configured to change a peak value frequency of the phase lead compensation according to a transmission ratio of the continuously variable transmission, and a second peak value frequency determination unit configured to change a peak value frequency of the phase delay compensation based on the peak value frequency of the lead compensation.

A belt-type continuously variable transmission includes a primary pulley, a secondary pulley, and a belt wound around the primary pulley and the secondary pulley. A controller performs a process, when performing a low speed position return shift to shift a transmission ratio toward a lowermost speed position while a vehicle is decelerating. The process includes: calculating a primary pressure actual lower limit, at which the belt actually starts to slip, based on the transmission ratio and a deceleration of the vehicle; setting a lower limit of a setpoint of the primary pressure to the primary pressure actual lower limit; setting the primary pressure actual lower limit higher with a locking tendency of a vehicle wheel detected than that without the locking tendency detected; and setting the primary pressure actual lower limit with the locking tendency detected to increase as the transmission ratio varies toward the lowermost speed position.

The invention is an improvement for the infinitely variable transmission (IVT) that utilizes oscillating torque to vary the mechanical power transmitted to a load. The invention provides the torque amplitude control system that is a compact device that adjusts the torque amplitude by controlling the phase angle between the forward and aft drive units for the IVT. The IVT is transmission which transfers the engine torque and power to the driveshaft, differential and wheels of an automobile. The torque is generated from centrifugal forces of masses in the forward and aft drive unites of the input assembly.

Provided is a control device for a continuously variable transmission, which is capable of effectively preventing occurrence of surge pressure due to a stroke of a driven pulley being stopped by abutment. The control device for the continuously variable transmission includes a pressure regulating valve regulating an oil pressure of oil supplied from an oil supply source to a cylinder chamber of the driven pulley, a control valve controlling the pressure regulating valve, and a control part controlling the control valve. If the control part determines that a gear ratio of the continuously variable transmission is maximum, as a first condition, when an instructed oil pressure of the control valve for the pressure regulating valve is larger than an oil pressure of oil supplied from the pressure regulating valve to the driven pulley, a control for lowering the instructed oil pressure is performed.