Transmission ratio controller and method for determining transmission ratio abnormality

A transmission ratio controller including circuitry, the circuitry comprising:

• a transmission ratio calculator configured to calculate a request transmission ratio to a transmission mechanism in accordance with a state of an internal combustion engine;
• a transmission ratio instructor configured to transmit a control signal to an actuation mechanism based on the request transmission ratio, the actuation mechanism being configured to actuate the transmission mechanism;
• and
• an abnormality determiner configured to determine whether a transmission ratio of the transmission mechanism is abnormal, wherein
• the state of the internal combustion engine is specified based on a specified parameter,
• the transmission ratio calculator is configured to calculate the request transmission ratio using a first transmission ratio map when the specified parameter satisfies a first condition,
• the transmission ratio calculator is configured to calculate the request transmission ratio using a second transmission ratio map that differs from the first transmission ratio map when the specified parameter satisfies a second condition,
• the first condition and the second condition are not simultaneously satisfied,
• when the specified parameter satisfies the first condition, the internal combustion engine is in a first state,
• when it is assumed that the specified parameter satisfies the second condition, the internal combustion engine is in a second state,
• the first state and the second state are identical except for the specified parameter, the abnormality determiner is configured, when the internal combustion engine is in the first state, to calculate a hypothetical transmission ratio using the second transmission ratio map based on the second state, and
• the abnormality determiner is configured, when the internal combustion engine is in the first state, to determine whether the transmission ratio of the transmission mechanism is abnormal based on a comparison of the hypothetical transmission ratio with at least one of the request transmission ratio, an instruction transmission ratio that is a transmission ratio corresponding to the control signal, or an actual transmission ratio that is a transmission ratio achieved by the transmission mechanism.