A variable displacement vane pump is described. The pump includes a control chamber provided between a housing and a control slide. A pressure-controlled relief valve is in fluid communication with the outlet path and moves to block or unblock a relief port based on output pressure of the lubricant. A feedback channel fluidly connects the control chamber to an inlet path of the pump. The feedback channel further connects to a control port that is connected to a main control valve. The relief valve and control valve are distinct and not fluidly connected. The relief valve moves once the pressure in the outlet path exceeds a predetermined amount, opening the relief port, and thus delivers a portion of the output lubricant to the control chamber via the relief port, thereby pressurizing the control chamber and reducing eccentricity of the pump by displacing the control slide.

One embodiment of a modular pump includes a cover and a housing that may be engaged with one another during operation. A gearset may be positioned within an internal portion of the housing. If the modular pump is configured as a rotary pump, the gear set may be comprised of an inner gear positioned within a portion of a ring gear. The modular pump may include a spacer positioned between the cover and the housing to allow the modular pump to be configured with gear sets of varying axial dimensions.

One embodiment of a modular pump includes a cover and a housing that may be engaged with one another during operation. A gearset may be positioned within an internal portion of the housing. If the modular pump is configured as a rotary pump, the gear set may be comprised of an inner gear positioned within a portion of a ring gear. The modular pump may include a spacer positioned between the cover and the housing to allow the modular pump to be configured with gear sets of varying axial dimensions.

Disclosed is a pump for dispensing lubricant to a system. The pump includes: a housing having an inlet for inputting lubricant into the housing and an outlet for delivering the lubricant therefrom. A control slide is pivotable about a pivot pin within the housing in a displacement increasing direction and a displacement decreasing direction to adjust pump displacement. A resilient structure biases the control slide in the displacement increasing direction. A pressure relief valve is mounted to the pivot pin and positioned along an outflow path leading pressurized lubricant from the control slide to the outlet. The pressure relief valve is biased in a closing direction and has a pressure receiving surface receiving pressure from the lubricant in the outflow path to urge the pressure relief valve in an opening direction. Opening the relief opening allows outflow of lubricant to relieve pressure in the outflow path.

Disclosed is a pump for dispensing lubricant to a system. The pump includes: a housing having an inlet for inputting lubricant into the housing and an outlet for delivering the lubricant therefrom. A control slide is pivotable about a pivot pin within the housing in a displacement increasing direction and a displacement decreasing direction to adjust pump displacement. A resilient structure biases the control slide in the displacement increasing direction. A pressure relief valve is mounted to the pivot pin and positioned along an outflow path leading pressurized lubricant from the control slide to the outlet. The pressure relief valve is biased in a closing direction and has a pressure receiving surface receiving pressure from the lubricant in the outflow path to urge the pressure relief valve in an opening direction. Opening the relief opening allows outflow of lubricant to relieve pressure in the outflow path.

One embodiment of a method for operating an internal combustion engine under a pressure less than atmospheric pressure includes the steps of positioning a vacuum pump such that said vacuum pump is in fluid communication with a crankcase of said internal combustion engine, connecting a discharge of said vacuum pump to a separator, wherein a portion of said discharge of said vacuum pump condenses in said separator, connecting a vapor discharge of said separator to a filter, wherein said filter removes a portion of volatile organic compounds from said vapor discharge, and venting said filter to an ambient atmosphere.

One embodiment of a method for operating an internal combustion engine under a pressure less than atmospheric pressure includes the steps of positioning a vacuum pump such that said vacuum pump is in fluid communication with a crankcase of said internal combustion engine, connecting a discharge of said vacuum pump to a separator, wherein a portion of said discharge of said vacuum pump condenses in said separator, connecting a vapor discharge of said separator to a filter, wherein said filter removes a portion of volatile organic compounds from said vapor discharge, and venting said filter to an ambient atmosphere.

A rotary, self-priming, positive displacement pump is described. The pump may include a pump housing including an inlet and an outlet, a pump chamber including an upper wall, a lateral wall, and a floor, first and second rotary impellers in the pump chamber, and a pair of gears each secured to the first and second rotary impellers, and a pressure relief feature operable to relieve pressure developing in a relatively high pressure zone of the pump chamber. The gears mesh with each other to ensure that the vanes do not contact one another during rotation. The pressure relief feature may comprise one or more channels formed in the pump housing and/or the first and second rotary impellers. The channels connect the high pressure zone with another zone to redistribute pressure. The channels may include one continuous channel or alternatively, a plurality of unconnected channels.

A rotary, self-priming, positive displacement pump is described. The pump may include a pump housing including an inlet and an outlet, a pump chamber including an upper wall, a lateral wall, and a floor, first and second rotary impellers in the pump chamber, and a pair of gears each secured to the first and second rotary impellers, and a pressure relief feature operable to relieve pressure developing in a relatively high pressure zone of the pump chamber. The gears mesh with each other to ensure that the vanes do not contact one another during rotation. The pressure relief feature may comprise one or more channels formed in the pump housing and/or the first and second rotary impellers. The channels connect the high pressure zone with another zone to redistribute pressure. The channels may include one continuous channel or alternatively, a plurality of unconnected channels.

Discharge port (26) as arc-recessed discharge portion is formed by cutting on bottom surface (13a) of pump accommodating portion (13) of variable displacement pump. On mounting surface (1b) of housing body (1), first low pressure chamber (281) is formed at position overlapping with discharge port (26) in radial direction of pump structure (14) formed by driving shaft (3), rotor (4) and vanes (5) Drain hole (28b) communicating with low pressure portion located outside housing body (1) is formed on bottom surface (28a) of first low pressure chamber (281) along direction of rotation axis (O1) of pump structure (14). Low pressure portion has pressure that is hydraulic pressure of oil discharged from discharge port (26) or less. Oil from discharge port (26), having higher pressure than first low pressure chamber (281), flows into first low pressure chamber (281) by pressure difference between discharge port (26) and first low pressure chamber (281).