A method of drivingly engaging a first motor of a dual motor drive unit with an output shaft driven by a second motor of the dual motor drive unit includes actuating a clutching device for drivingly engaging the first motor with the output shaft. Next, a rotational speed of the first motor is synchronized with a rotational speed of the output shaft. When the rotational speed of the first motor and the rotational speed of the output shaft are synchronized, an output torque of the first motor is reduced. When the clutching device drivingly engages the first motor with the output shaft, the output torque of the first motor is increased. The invention further relates to a dual motor drive unit for carrying out the method.

A series hydraulic hybrid system for a vehicle may have: a hydraulic circuit with a first hydraulic displacement unit in fluid communication with a second hydraulic displacement unit, a hydraulic actuator, and a hydraulic accumulator assembly. The hydraulic accumulator assembly is selectively in fluid communication with the hydraulic circuit via at least one controllable circuit valve. The hydraulic accumulator assembly is selectively in fluid communication with the hydraulic actuator via at least one controllable actuator valve, such that the hydraulic accumulator assembly is configured to be selectively fluidly connected with and to be selectively fluidly disconnected from the hydraulic actuator via the at least one actuator valve independently of a control position of the at least one circuit valve. A method of operating the system is also described.

A series hydraulic hybrid system for a vehicle may have: a hydraulic circuit with a first hydraulic displacement unit in fluid communication with a second hydraulic displacement unit, a hydraulic actuator, and a hydraulic accumulator assembly. The hydraulic accumulator assembly is selectively in fluid communication with the hydraulic circuit via at least one controllable circuit valve. The hydraulic accumulator assembly is selectively in fluid communication with the hydraulic actuator via at least one controllable actuator valve, such that the hydraulic accumulator assembly is configured to be selectively fluidly connected with and to be selectively fluidly disconnected from the hydraulic actuator via the at least one actuator valve independently of a control position of the at least one circuit valve. A method of operating the system is also described.

An energy storage and regeneration system that converts irregular, non-constant, and variable input power to regular, constant, and controlled output power using hydraulics whereby the irregular input power is used to pump hydraulic fluid into an accumulator array where it is stored pressurized. Energy is released in a controlled fashion using a hydraulic motor operated by the pressurized hydraulic fluid from the accumulator array, in accordance with the specified power demand. One or more power units may be deployed depending on the amount of energy required at the output. Each power unit includes a hydraulic motor and associated floating accumulator whose internal pressure is controlled to maintain a substantially constant pressure differential across its associated motor. The system can be integrated into various energy system sources including renewable energy such as wind, PV or thermal solar, wave, tidal, etc. as well as various types of vehicles such as cars, trucks, motorcycles, trains, boats, etc.

The invention relates to a hydraulic circuit provided with at least one hydraulic power machine (2, 4) connected to a low-pressure circuit (6) and to a high-pressure circuit (10) transmitting said power, wherein the machine is provided with a drain which allows internal leaks in the casing thereof to flow towards a low-pressure accumulator (8) or a vessel at atmospheric pressure, said circuit comprising an intake pipe (30) connecting the low-pressure circuit (6) to the casing of the machine, and an outlet pipe (36) forming the drain receiving the flow from the intake pipe in order to guide same towards the vessel (8), including a heat exchanger (42) and a filter (44) forming the fluid treatment elements for the entire hydraulic circuit, said circuit also comprising a means for monitoring the flow (40) in the intake and outlet pipes.

The invention relates to a hydraulic circuit provided with at least one hydraulic power machine (2, 4) connected to a low-pressure circuit (6) and to a high-pressure circuit (10) transmitting said power, wherein the machine is provided with a drain which allows internal leaks in the casing thereof to flow towards a low-pressure accumulator (8) or a vessel at atmospheric pressure, said circuit comprising an intake pipe (30) connecting the low-pressure circuit (6) to the casing of the machine, and an outlet pipe (36) forming the drain receiving the flow from the intake pipe in order to guide same towards the vessel (8), including a heat exchanger (42) and a filter (44) forming the fluid treatment elements for the entire hydraulic circuit, said circuit also comprising a means for monitoring the flow (40) in the intake and outlet pipes.

A hydraulic transmission circuit is provided having at least two elementary hydraulic motors, each having a secondary enclosure and a main duct for fluid feed and a secondary enclosure and a main duct for fluid discharge. A fluid distributor distributes fluid from the main ducts to the elementary motors via the secondary enclosures. A control system controls the elementary motors. Valves connecting the fluid distributor to the secondary enclosures of the first motor put a secondary enclosure into communication with a main duct independent of an operating mode of any other elementary motor.

A hydraulic transmission circuit is provided having at least two elementary hydraulic motors, each having a secondary enclosure and a main duct for fluid feed and a secondary enclosure and a main duct for fluid discharge. A fluid distributor distributes fluid from the main ducts to the elementary motors via the secondary enclosures. A control system controls the elementary motors. Valves connecting the fluid distributor to the secondary enclosures of the first motor put a secondary enclosure into communication with a main duct independent of an operating mode of any other elementary motor.

An energy storage and regeneration system that converts irregular, non-constant, and variable input power to regular, constant, and controlled output power using hydraulics whereby the irregular input power is used to pump hydraulic fluid into an accumulator array where it is stored pressurized. Energy is released in a controlled fashion using a hydraulic motor operated by the pressurized hydraulic fluid from the accumulator array, in accordance with the specified power demand. One or more power units may be deployed depending on the amount of energy required at the output. Each power unit includes a hydraulic motor and associated floating accumulator whose internal pressure is controlled to maintain a substantially constant pressure differential across its associated motor.

A hydrostatic drive system (1) has a hydrostatic pump (3) driven by a drive motor (2) and connected in a closed circuit with a hydrostatic motor (4). The hydrostatic motor (4) drives a consumer (5) and the closed circuit is formed by a first hydraulic connection (6a) and a second hydraulic connection (6b). A hydrostatic accumulator (30) can be connected with at least one of the two hydraulic connections (6a, 6b). A hydrostatic drive unit is located in an accumulator flow path (21) between one of the two hydraulic connections (6a, 6b) and the hydrostatic accumulator (30) and an additional hydrostatic drive unit is located in a tank flow path (22) between the other of the two hydraulic connections (6a, 6b) and a tank (17). The hydrostatic drive unit and the additional hydrostatic drive unit are a hydrostatic dual-flow double drive unit (20) provided in the accumulator flow path (21) and in the tank flow path (22).