A vehicle drive device is well known that includes a hydraulic power transmission device having an input-side rotating element to which power from an engine is input and an output-side rotating element outputting power to drive wheels. For example, this corresponds to a vehicle drive device described in Patent Document 1. Such a vehicle drive device has an engine rotation speed (corresponding to a rotation speed of the input-side rotating element of the hydraulic power transmission device) passively determined depending on a vehicle speed (corresponding to a rotation speed of the output-side rotating element of the hydraulic power transmission device), a hydraulic characteristic of the hydraulic power transmission device, and an engine output. Power transmission efficiency is also passively determined in a mechanical path hydraulically transmitting the engine output through the hydraulic power transmission device.
USPTO Backgrounds
USPTO Backgrounds