A vehicle hydraulic system includes a transmission lube circuit, a variable displacement main pump having an inlet, and a variable displacement charge pump having an outlet and a pressure responsive displacement control unit. The system also includes a charge line communicating the charge pump outlet with the main pump inlet, a sensing line communicating the charge line with the displacement control unit, and a lube line communicating the charge pump outlet with the lube circuit. The lube line includes a fluid restriction. A hydraulic oil filter and a filter bypass valve are connected in parallel between the outlet of the charge pump and the charge line.

A vehicle hydraulic system includes a transmission lube circuit, a variable displacement main pump having an inlet, and a variable displacement charge pump having an outlet and a pressure responsive displacement control unit. The system also includes a charge line communicating the charge pump outlet with the main pump inlet, a sensing line communicating the charge line with the displacement control unit, and a lube line communicating the charge pump outlet with the lube circuit. The lube line includes a fluid restriction. A hydraulic oil filter and a filter bypass valve are connected in parallel between the outlet of the charge pump and the charge line.

A lubricating system for supplying at least one lubricating point with lubricant is described. The lubricating system is equipped with at least one feed device and at least one line extending between this feed device and a lubricating point. In order to very easily and effectively monitor and indicate the severance of a lubricant line, an electrical connection is respectively provided on the feed device and the lubricating point. An electric conductor extending between the two connections is assigned to the line. A monitoring device is assigned to the line in such a way that it generates a signal when the electric conductor is interrupted. The invention furthermore pertains to a vehicle, particularly a construction machine, which is equipped with such a lubricating system.

A temperature controlled axle cooling system and method is disclosed. Axle hydraulic circuits cool oil circulating through vehicle axles, and sensors monitor axle temperatures. Pumps are activated to circulate the oil through the axle circuits based on the axle temperatures. Each axle circuit can be a separate closed-loop hydraulic system, not sharing fluid with any other vehicle or axle hydraulic systems. All axle cooling system pumps can be activated when any axle temperature exceeds a high threshold. All pumps can be deactivated when all axle temperatures are below a low threshold. Each pump can be activated and deactivated based only on that axle's temperature. The axle cooling system pumps can be driven by motors powered by the main vehicle hydraulic system flow. A valve can be controlled based on axle temperature to allow main vehicle hydraulic system flow. Multiple pumps can be driven by a single motor.

In hybrid electric vehicles having increased battery storage capacity and plug-in capability, electric-only operation of significant duration is available. To supplement lubrication for the electric and mechanical components provided in a fluid circuit by an engine-driven mechanical pump, an electric pump is provided in parallel to the mechanical pump. When the electric pump is operating, a diagnostic can be performed to determine system integrity. According to one embodiment, an actual quantity provide to the circuit is determined; an expected quantity is estimated; and a fault is determined when the actual and expected quantities differ by more than a predetermined amount. The fault may indicate a leak or plug in the fluid circuit or a failure of a component in the fluid circuit.

In hybrid electric vehicles having increased battery storage capacity and plug-in capability, electric-only operation of significant duration is available. To supplement lubrication for the electric and mechanical components provided in a fluid circuit by an engine-driven mechanical pump, an electric pump is provided in parallel to the mechanical pump. When the electric pump is operating, a diagnostic can be performed to determine system integrity. According to one embodiment, an actual quantity provide to the circuit is determined; an expected quantity is estimated; and a fault is determined when the actual and expected quantities differ by more than a predetermined amount. The fault may indicate a leak or plug in the fluid circuit or a failure of a component in the fluid circuit.

A cooling and lubrication device of an electric drive assembly and an electric drive assembly are disclosed. The cooling and lubrication device includes an oil pumping unit, an oil pumping passage, and an oil returning passage. Outlets of oil distribution passages correspond to parts to be cooled and parts to be lubricated inside the motor housing, as well as parts to be cooled and parts to be lubricated. The oil pumping unit pumps the lubricating oil inside the first housing into the oil pumping passage, and transfers the lubricating oil to the parts to be cooled and the parts to be lubricated. The oil returning passage allows the lubricating oil inside the second housing to flow back into the first housing. This cooling and lubrication device can achieve active and directional cooling and lubrication of the parts to be cooled and the parts to be lubricated.

A vehicle drive shaft grease system. The vehicle drive shaft grease system comprises a cylindrical housing having a first open end and a second open end. The housing is detachedly affixed to a vehicle support frame by at least one solid tether, and tabs mounted on an outside surface of the cylindrical housing. Grease is distributed to the device and the device distributes the grease through a series of openings and channels to those components requiring the grease.

A vehicle drive shaft grease system. The vehicle drive shaft grease system comprises a cylindrical housing having a first open end and a second open end. The housing is detachedly affixed to a vehicle support frame by at least one solid tether, and tabs mounted on an outside surface of the cylindrical housing. Grease is distributed to the device and the device distributes the grease through a series of openings and channels to those components requiring the grease.

In hybrid electric vehicles having increased battery storage capacity and plug-in capability, electric-only operation of significant duration is available. To supplement lubrication for the electric and mechanical components provided in a fluid circuit by an engine-driven mechanical pump, an electric pump is provided in parallel to the mechanical pump. When the electric pump is operating, a diagnostic can be performed to determine system integrity. According to one embodiment, an actual quantity provide to the circuit is determined; an expected quantity is estimated; and a fault is determined when the actual and expected quantities differ by more than a predetermined amount. The fault may indicate a leak or plug in the fluid circuit or a failure of a component in the fluid circuit.