High pressure pump and method of reducing fluid mixing within same

Abstract

Mixing of lubrication fluid and pumped fluid within a pump can undermine lubricity of the lubrication fluid and / or contaminate the pumped fluid (e.g. fuel) with lubrication fluid. In order to reduce mixing of fluids within a high pressure pump of the present disclosure, a lubrication fluid is supplied to the high pressure pump. A low pressure pump supplies a second fluid to the high pressure pump. The pressure of the second fluid is increased within at least one piston bore of the high pressure pump. Mixing of the lubrication fluid and the second fluid is reduced by fluidly connecting a weep annulus which is opened to the at least one piston bore to a low pressure pump inlet of the low pressure pump.

Description

Technical field [0001] The present invention relates generally to high pressure pumps, and more specifically to reducing the mixing of fluids in high pressure pumps. Background technique [0002] Lubricating fluid, such as engine oil, is usually pumped through a fluid pump to lubricate the moving parts of the pump. The mixing of the lubricating fluid and the pumped fluid can destroy the lubricity of the lubricating fluid and / or contaminate the pumped fluid by the lubricating fluid. For example, many fuel systems include a low-pressure transfer pump that draws fuel from a fuel tank and a high-pressure pump that raises the fuel pressure before injection. Generally, the lubricating fluid of engine oil flows in the high-pressure pump to lubricate the moving parts. The reciprocating piston driven by the cam in the piston hole of the high-pressure pump increases the pressure of the fuel. The reciprocating motion of the piston and the pressure in the piston bore will cause some fuel ...

AI Technical Summary

Problems solved by technology

However, the reciprocating pistons that pump many fluids are subject to extreme pressure changes, thereby reducing seal life and sealing ability

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