Abstract: 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.

Abstract: A hydraulic hybrid vehicle includes elements such as a hydraulic pump driven by an internal combustion engine and arranged to draw in low pressure fluid and pump the fluid at high pressure to an accumulator. A hydraulic motor is powered by the pressurized fluid. Safety processes are provided for detecting and addressing a number of conditions that may arise in the operation of the hydraulic hybrid vehicle, including an initialization procedure for start-up of the vehicle, a shut-down procedure, and procedures for detecting and responding to failure of the pump or motor, internal and external fluid leaks, and non-responsive actuation and mode control systems.

Abstract: 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.

Abstract: A method for operating a series hybrid vehicle is provided, in which an engine generates secondary power that is either stored or used as direct input energy by a secondary power source to provide motive power to the vehicle. Regenerative braking is used to convert kinetic energy of the vehicle into secondary energy, which is also stored. When the vehicle driver makes a power demand, the secondary power source is powered by secondary energy from an energy storage device, direct input energy generated by the engine, or both, depending on the amount of stored secondary energy in combination with vehicle speed. When in use, the power level at which the engine is operated is also determined on the basis of available stored energy and vehicle speed. At higher vehicle speeds, the amount of stored energy is allowed to be depleted in order to increase the available storage capacity for regenerative braking.