HYDRAULIC HYBRID VEHICLE WITH LARGE-RATIO SHIFT TRANSMISSION AND METHOD OF OPERATION THEREOF

摘要

A vehicle includes an internal combustion engine configured to power a hydraulic pump to pressurize hydraulic fluid, which is used to power the vehicle directly or is stored in an accumulator. A drive module, including a hydraulic pump/motor and a multi-speed mechanical transmission, is operatively coupled to drive wheels of the vehicle to provide motive power to the vehicle. The drive module can also include a second hydraulic motor (or multiple hydraulic motors) configured to provide motive power. The transmission is configured to progress through its gears at ratio shifts of no less than 2:1 between adjacent gear positions. The transmission is configured to place the hydraulic motor in neutral during some portions of vehicle operation, and to engage the motor during other portions of vehicle operation.