A control device and a transmission system are provided that allow for comfortable traveling with a human-powered vehicle. The control device includes an electronic controller configured to control a transmission to shift a transmission ratio of a human-powered vehicle in accordance with a first shifting condition set based on a first reference value. The electronic controller is configured to shift the transmission ratio of the human-powered vehicle regardless of the first shifting condition upon determining a second shifting condition set based on travel information related to traveling of the human-powered vehicle is satisfied.

A CVT acceleration control method applied to a CVT-mounted vehicle including an accelerator position sensor, a vehicle speed sensor, a driving pulley rotation sensor and a driven pulley rotation sensor that is configured to detect a rotation speed of a driven pulley and to output a corresponding signal, a CVT operation portion and a controller, the CVT acceleration control method, may include determining, by the controller, whether a current vehicle driving state satisfies a predetermined starting control condition, monitoring, by the controller, a current driving pulley rotation speed change, determining, by the controller, whether the current vehicle driving state satisfies a predetermined trigger condition, setting, by the controller, a target driving pulley rotation speed change, and controlling, by the controller, the operation of the CVT operation portion such that the current driving pulley rotation speed change converges to the target driving pulley rotation speed change.

A nonlinear closed-loop control combined with an integral time-delay feedback control is disclosed to adjust a speed ratio of an infinitely variable transmission (IVT) system. A speed ratio control for an IVT system involves a forward speed controller and a crank length controller for different speed ranges. The time-delay control is designed to reduce speed fluctuations of the output speed of an IVT with an accurate speed ratio. The speed ratio of an IVT with the disclosed control strategy can achieve an excellent tracking response for the desired constant output speed and reduce speed fluctuations of the output speed of an IVT by the time-delay feedback control.

A nonlinear closed-loop control combined with an integral time-delay feedback control is disclosed to adjust a speed ratio of an infinitely variable transmission (IVT) system. A speed ratio control for an IVT system involves a forward speed controller and a crank length controller for different speed ranges. The time-delay control is designed to reduce speed fluctuations of the output speed of an IVT with an accurate speed ratio. The speed ratio of an IVT with the disclosed control strategy can achieve an excellent tracking response for the desired constant output speed and reduce speed fluctuations of the output speed of an IVT by the time-delay feedback control.

An automatic transmission includes a starting clutch which connects and disconnects motive power between an engine and a transmission mechanism. The starting clutch includes a clutch hub connected to the engine, a clutch drum connected to the transmission mechanism, a friction plate provided between the clutch hub and the clutch drum, and a piston which presses the friction plate. The clutch drum has a radial-direction portion extending from an end portion of the outer-side cylindrical portion on a first axial-direction side to the radial-direction inner side, and an annular oil dam member extending from an end portion of the outer-side cylindrical portion on a second axial-direction side to the radial-direction inner side to immerse the friction plate in oil supplied from the radial-direction inner side toward the outer side, together with the outer-side cylindrical portion and the radial-direction portion.

An automatic transmission includes a starting clutch which connects and disconnects motive power between an engine and a transmission mechanism. The starting clutch includes a clutch hub connected to the engine, a clutch drum connected to the transmission mechanism, a friction plate provided between the clutch hub and the clutch drum, and a piston which presses the friction plate. The clutch drum has a radial-direction portion extending from an end portion of the outer-side cylindrical portion on a first axial-direction side to the radial-direction inner side, and an annular oil dam member extending from an end portion of the outer-side cylindrical portion on a second axial-direction side to the radial-direction inner side to immerse the friction plate in oil supplied from the radial-direction inner side toward the outer side, together with the outer-side cylindrical portion and the radial-direction portion.

An automatic transmission includes a clutch device having a clutch hub, a clutch drum, a friction plate, a piston, and a hydraulic chamber. The clutch drum includes an outer-side cylindrical portion, a disc-shaped first radial portion extending radially inwardly, an axial portion extending axially from the first radial portion, and a disc-shaped second radial portion extending radially inwardly from the axial portion. The piston includes a pressing portion disposed between the first radial portion and the friction plate side, and a disc-shaped piston radial portion extending radially inwardly from the pressing portion. The hydraulic chamber is provided radially inwardly from the axial portion and on the non-friction-plate side of the piston radial portion. A comb-teeth portion is provided at a radially intermediate portion of the piston radial portion. The axial portion and the piston radial portion intersect with each other in a comb-teeth shape.

A transmission system associated with a vehicle includes a shaft to rotate about an axis of rotation. The shaft is coupled to a gear set. The transmission system includes a sensor target to be coupled to the gear set and to rotate with the gear set. The sensor target includes at least one target. The transmission system includes a sensor spaced apart from the sensor target by a gap. The sensor is configured to observe the at least one target of the sensor target to determine a rotation speed of the shaft.

An on-board component abnormal site identifying method includes executing an acquisition process, a calculation process, and a reporting process by an execution device. The acquisition process is a process for acquiring, by the execution device, values of input variables. The mapping includes, as the input variables, a foreign substance variable, and includes, as an output variable, an abnormal site variable. The calculation process is a process for calculating, by the execution device, a value of the abnormal site variable by inputting, to the mapping, the values of the input variables acquired through the acquisition process. The reporting process is a process for reporting, by the execution device, a calculation result of the calculation process by operating a reporting device.

An on-board component abnormal site identifying method includes executing an acquisition process, a calculation process, and a reporting process by an execution device. The acquisition process is a process for acquiring, by the execution device, values of input variables. The mapping includes, as the input variables, a foreign substance variable, and includes, as an output variable, an abnormal site variable. The calculation process is a process for calculating, by the execution device, a value of the abnormal site variable by inputting, to the mapping, the values of the input variables acquired through the acquisition process. The reporting process is a process for reporting, by the execution device, a calculation result of the calculation process by operating a reporting device.