Electric assist system and electric assist vehicle

An electric power assist system for an electric assist vehicle, the electric power assist system comprising:

• an electric motor that generates an assist power to assist human power of a rider of the electric assist vehicle;
• a controller configured or programmed to control a magnitude of the assist power to be generated by the electric motor;
• and
• an acceleration sensor that outputs an acceleration signal representing at least one of an acceleration in a first direction as a travel direction of the electric assist vehicle and an acceleration in a second direction perpendicular to both of the first direction and a road surface;
• wherein
• the controller is configured or programmed to use the acceleration signal to determine that the electric assist vehicle is in a stop state, to determine an inclination angle of the road surface based on the acceleration signal that is output in the stop state, and to cause the electric motor to generate an assist power of a magnitude in accordance with the inclination angle when the rider starts pedaling the electric assist vehicle.

An electric power assist system for an electric assist vehicle, the electric power assist system comprising:

• an electric motor that generates an assist power to assist human power of a rider of the electric assist vehicle;
• a controller configured or programmed to generate a signal that controls an electric current in the electric motor to control a magnitude of the assist power to be generated by the electric motor;
• and
• an acceleration sensor that outputs an acceleration signal representing at least one of an acceleration in a first direction as a travel direction of the electric assist vehicle and an acceleration in a second direction perpendicular to both of the first direction and a road surface;
• the controller is configured or programmed to receive a detection signal based on whether the electric assist vehicle is at a stop or is running, the detection signal being received from at least one sensor that outputs the detection signal;
• and
• the controller is configured or programmed to determine, based on the detection signal, that the electric assist vehicle is in a stop state, to determine an inclination angle of the road surface based on the acceleration signal that is output in the stop state, and to cause the electric motor to generate an assist power of a magnitude in accordance with the inclination angle when the rider starts pedaling the electric assist vehicle.