A method for controlling operation of a hydraulic idle stop and go (ISG) system using an electro hydraulic power steering (EHPS) system includes measuring a pressure in an accumulator, a steering angle, and a steering angular velocity; determining whether the measured pressure in the accumulator is less than an absolute value of a first reference pressure; determining whether the measured steering angle is less than an absolute value of a reference angle when the measured pressure in the accumulator is less than the absolute value of the first reference pressure; determining whether the measured steering angular velocity is less than an absolute value of a reference angular velocity when the measured steering angle is less than the absolute value of the reference angle; and opening a solenoid valve when the measured steering angular velocity is less than the absolute value of the reference angular velocity.

A system and method are provided for hybrid electric internal combustion engine applications in which a motor-generator, a narrow switchable coupling and a torque transfer unit therebetween are arranged and positioned in the constrained environment at the front of an engine in applications such as commercial vehicles, off-road vehicles and stationary engine installations. The motor-generator is preferably positioned laterally offset from the switchable coupling, which is co-axially-arranged with the front end of the engine crankshaft. The switchable coupling is an integrated unit in which a crankshaft vibration damper, an engine accessory drive pulley and a disengageable clutch overlap such that the axial depth of the clutch-pulley-damper unit is nearly the same as a conventional belt drive pulley and engine damper. The front end motor-generator system includes an electrical energy store that receives electrical energy generated by the motor-generator when the coupling is engaged. When the coupling is disengaged, the motor-generator may drive the pulley portion of the clutch-pulley-damper to drive the engine accessories using energy returned from the energy store, independent of the engine crankshaft.

A system and method are provided for hybrid electric internal combustion engine applications in which a motor-generator, a narrow switchable coupling and a torque transfer unit therebetween are arranged and positioned in the constrained environment at the front of an engine in applications such as commercial vehicles, off-road vehicles and stationary engine installations. The motor-generator is preferably positioned laterally offset from the switchable coupling, which is co-axially-arranged with the front end of the engine crankshaft. The switchable coupling is an integrated unit in which a crankshaft vibration damper, an engine accessory drive pulley and a disengageable clutch overlap such that the axial depth of the clutch-pulley-damper unit is nearly the same as a conventional belt drive pulley and engine damper. The front end motor-generator system includes an electrical energy store that receives electrical energy generated by the motor-generator when the coupling is engaged. When the coupling is disengaged, the motor-generator may drive the pulley portion of the clutch-pulley-damper to drive the engine accessories using energy returned from the energy store, independent of the engine crankshaft.

A hydrostatic drive system of a mobile machine includes a hydraulic work system and a hydraulic work pump that is driven by an internal combustion engine and, when operated as a pump, takes in hydraulic fluid with a suction side from a tank and, with a delivery side, delivers into a delivery line that leads to the hydraulic work system. A bypass valve is provided with which, when the hydraulic work pump is operated as a motor to start the shut-off internal combustion engine, the volume flow delivered by the hydraulic work pump operated as a motor to the delivery side is diverted to the tank. The bypass valve, in the motor operation to start the shut-off internal combustion engine, is actuated into an open position that connects the delivery side of the hydraulic work pump with the tank.

A hydrostatic drive system of a mobile machine includes a hydraulic work system and a hydraulic work pump that is driven by an internal combustion engine and, when operated as a pump, takes in hydraulic fluid with a suction side from a tank and, with a delivery side, delivers into a delivery line that leads to the hydraulic work system. A bypass valve is provided with which, when the hydraulic work pump is operated as a motor to start the shut-off internal combustion engine, the volume flow delivered by the hydraulic work pump operated as a motor to the delivery side is diverted to the tank. The bypass valve, in the motor operation to start the shut-off internal combustion engine, is actuated into an open position that connects the delivery side of the hydraulic work pump with the tank.

Method for controlling a hydraulic pumping system that is stationary while in operation, the pumping system comprising a fuel-driven drive with a motor for a pump, a heating device for heating the motor and an accumulator with a charge control, the method comprising the steps of: detecting at least a first operating value, determining a current and an expected operating mode, and influencing at least a second operating value. Further, a control device for a hydraulic pumping system that is stationary while in operation, and a hydraulic pumping system that is stationary while in operation are also provided.

An engine assembly may include an internal combustion engine and an expander couplable to the internal combustion engine in a force transmitting manner. The engine assembly may also include a pulley mounted rotatably on a shaft of the expander. The pulley may be coupled to the internal combustion engine in a force-transmitting manner via a belt drive. The engine assembly may further include a first driver plate connected non-rotatably to the pulley and a second driver plate arranged adjacent thereto and connected non-rotatably to the shaft. The engine assembly may additionally include a clutch device including at least one actuating device and a coupling wheel. The coupling wheel may contact the first driver plate and the second driver plate when the clutch device is closed such that the pulley is connected with the shaft of the expander in a driving manner.

A hydraulic circuit device for a vehicle, includes a clutch, a flow path, a fluid pump, a pressure generating device, and a control valve. The control valve is configured to determine whether a transmission start-stop function activation condition other than a vehicle speed is satisfied, determine whether a system start-stop function activation condition related to a component of the vehicle is satisfied, the component being other than the transmission, determine whether the vehicle speed is equal to or lower than a first speed threshold, and boost a line pressure of the flow path to accumulate pressure in the pressure generating device for preparing activation of the start-stop function if it is determined that the transmission start-stop function activation condition and the system start-stop function activation condition are satisfied, and if it is determined that the vehicle speed is equal to or lower than the first speed threshold.

A drive system, in particular for a self-propelled construction machine, in particular a soil compactor, comprising an internal combustion engine comprising a drive unit, at least one hydraulic circuit with a hydraulic pump that can be driven by the drive unit, as well as a hydraulic-drive support unit with a hydraulic pump/motor assembly and at least one pressure fluid reservoir, wherein the hydraulic pump/motor assembly is or can be drivingly coupled with the drive unit or/and at least one hydraulic circuit, wherein the hydraulic pump/motor assembly can be operated in a charging operating mode by the drive unit or/and at least one hydraulic circuit as a pump to charge at least one pressure fluid reservoir and be operated in an drive support operating mode as a motor to provide a drive support torque for the hydraulic pump of at least one hydraulic circuit, characterized in that the hydraulic pump/motor assembly can be operated in a recirculation operating mode as a motor to start the drive unit.

A drive system, in particular for a self-propelled construction machine, in particular a soil compactor, comprising an internal combustion engine comprising a drive unit, at least one hydraulic circuit with a hydraulic pump that can be driven by the drive unit, as well as a hydraulic-drive support unit with a hydraulic pump/motor assembly and at least one pressure fluid reservoir, wherein the hydraulic pump/motor assembly is or can be drivingly coupled with the drive unit or/and at least one hydraulic circuit, wherein the hydraulic pump/motor assembly can be operated in a charging operating mode by the drive unit or/and at least one hydraulic circuit as a pump to charge at least one pressure fluid reservoir and be operated in an drive support operating mode as a motor to provide a drive support torque for the hydraulic pump of at least one hydraulic circuit, characterized in that the hydraulic pump/motor assembly can be operated in a recirculation operating mode as a motor to start the drive unit.