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.

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 method for operating a vehicle drive train (1) includes, during a downshift, disengaging at least one shift element (A through F) from a power flow of the transmission (5), guiding a power transmission capacity of a torque converter lockup clutch (4) to a level at which the torque converter lockup clutch (4) is in a non-slip operating condition during a positive engine override when a rotational speed of a prime mover (2) is guided towards a synchronous speed of a demanded desired ratio, and guiding the power transmission capacity of the torque converter lockup clutch (4)no later than a point in time of the downshift at which the rotational speed of the prime mover (2) is equal to the synchronous speed of the desired ratioto a level at which the torque converter lockup clutch (4) is transferred into a continuous slip operation due to torque.

A method for controlling gear shifting, including: acquiring a current gear-shifting parameter of the vehicle (101); according to the current gear-shifting parameter and a preset target rotational speed, determining a gear-shifting inputted rotational speed (102); and when a rotational speed of the vehicle reaches the gear-shifting inputted rotational speed, controlling a shifting fork to start up a gear-shifting operation (103). The method for controlling gear shifting presets the target rotational speed of the gears, and, according to the current gear-shifting parameter of the vehicle that is acquired in real time and the preset target rotational speed, inversely calculates the gear-shifting inputted rotational speed, whereby the gear-shifting inputted rotational speed is an accurate gear-shifting inputted rotational speed that matches with the current condition of the vehicle. When the rotational speed of the vehicle reaches the gear-shifting inputted rotational speed, the shifting fork is controlled to start up a gear-shifting operation, which can realize the accurate gear shifting of the vehicle, which greatly improves the stability of the vehicle when a dual-clutch automatic transmission is performing gear shifting.

A transmission includes a shift drum, an angular sensor, and a control unit. The control unit has reference values of the output values at a first rotation angle and a second rotation angle of the shift drum. The control unit is configured to obtain the output values at the first rotation angle and the second rotation angle as a first output value and a second output value, respectively. The control unit is configured to correct the output value output between the first rotation angle and the second rotation angle based on a difference between the first output value and the reference value at the first rotation angle and a difference between the second output value and the reference value at the second rotation angle.

A controller executes a feedback control of a transmission so that an actual speed ratio reaches a target speed ratio. The controller includes first and second phase lead compensators configured to perform phase lead compensation of a feedback primary command pressure, a lead compensation on/off determination unit configured to determine to set on or off the phase lead compensation, and an advance amount filter unit configured to smooth a change of a gain according to on/off determination of the phase lead compensation when the phase lead compensation is on/off-switched.

A straddled vehicle includes a gear position sensor abnormality detector which is configured to detect an abnormality of a gear position sensor which is provided at a crankshaft-supporter-integrated transmission supporter. The gear position sensor abnormality detector determines that the gear position sensor has an abnormality when the shift of a straddled vehicle from a stopped state to a running state is detected based on a signal from a rotation speed sensor while the gear position detected by the gear position sensor is included in a high-speed gear position class. Furthermore, the gear position sensor abnormality detector determines that the gear position sensor has an abnormality when the gear position detected by the gear position sensor is included in a low-speed gear position class and is different from a gear position estimated based on a signal from a crankshaft sensor and a signal from the rotation speed sensor.

A power transmission control device acquires rotation speed information of an idle gear corresponding to a target engagement member and rotation speed information of a sleeve corresponding to an engagement member, sets one rotation speed changeable by a power source as a synchronization side rotation speed, sets the other rotation speed as a target synchronization side rotation speed, allows a differential rotation between the synchronization side rotation speed and the target synchronization side rotation speed to match a predetermined differential rotation by changing the synchronization side rotation speed using the power source after a power transmission releasing state is selected due to a gear changing request, performs an engagement operation, inverts a sign of the predetermined differential rotation, and switches to the power transmission state while allowing the differential rotation to match the predetermined differential rotation of which the sign is inverted.

A failure judgment device of an automatic transmission includes: a first abnormality judging section configured to judge a power supply fault abnormality or a breaking abnormality of the solenoid, from a selected shift stage and a state of the transmission mechanism, after the detection of the electric abnormality; and a second abnormality judging section configured to judge the power supply abnormality or the breaking abnormality of the solenoid, from the monitor current value when the solenoid valve is switched to an OFF state, after the detection of the electric abnormality, when one of the first abnormality judging section and the second abnormality judging section judges the power supply fault abnormality or the breaking abnormality, the judgement result being outputted.