Debris Diverter Shield For Fuel Injector
AssigneeStanadyne, Inc.
InventorMark S. CAVANAGH
Life of this patent
Estimating the term…
Abstract
A tubular debris shield and diverter mounted in a high pressure flow passage within a fuel injector, provide the dual functions of passing the main flow of high pressure fuel with large debris particles to relatively large discharge openings, such as the injector spray holes, while allowing some high pressure fuel to flow through a multitude of very small transverse holes to a sensitive hydraulic component, such an injector control valve circuit. In one embodiment, the tube has a wall thickness in the range of about 0.1 to 0.5 mm at least about 2000 holes with a diameter in the range of about 20 to 30 microns.
Claims18
A fuel injector comprising:
- an elongated body having upper and lower ends, a longitudinal bore leading to an injector valve seat adjacent the lower end and to a tip with discharge holes at the lower end;
- an injector valve reciprocable in said bore, having a lower end sealable against the injector valve seat and an upper end subject to fluid pressure in an injector control chamber;
- a control valve with an upstream side in fluid communication with said injector control chamber and a downstream side in fluid communicating with a low pressure sump;
- a high pressure fuel supply passage in the body, in fluid communication with said bore upstream of the injector valve seat, and a branch line from the high pressure passage in fluid communication with said injector control chamber and with the upstream side of said control valve;
- an actuator for selectively closing and opening the control valve, whereby when the control valve is closed high pressure fuel in said control chamber urges the injector valve against the injector valve seat to prevent flow of high pressure fuel from said bore to the discharge holes and when the control valve is opened the control chamber is fluidly connected with the low pressure sump, thereby reducing the fluid pressure in the control chamber and on the upper end of the injector valve, lifting the injector valve off the injector seat and discharging fuel through the discharge holes;
- a debris shield in the high pressure fuel supply passage upstream of said branch line, comprising a tube fixed to the body, with a central passage aligned with the fuel supply passage and a multiplicity of transverse holes through which high pressure fuel is delivered to the branch line.
A fuel injector comprising:
- a high pressure fuel supply passage;
- a hydraulically controlled injector valve operatively associated with the fuel supply passage and with injection holes for discharging high pressure fuel from the injector;
- a control valve hydraulically controlling the injector valve, with an upstream side in fluid communication with said fuel supply passage and a downstream side in fluid communicating with a low pressure sump;
- an actuator for selectively closing and opening the control valve, whereby when the control valve is closed hydraulic forces close the injector valve to prevent flow of high pressure fuel to the discharge holes and when the control valve is opened hydraulic forces open the injector valve to discharge fuel through the discharge holes;
- a debris shield in the high pressure fuel supply passage comprising a tubular tube with a central axial passage and a multiplicity of radial holes.
- wherein high pressure fuel for injection passes axially through the tube and high pressure fuel to the upstream side of the control valve passes radially through the holes in the tube.
A fuel injector having a main high pressure fuel passage and an auxiliary passage from the main passage to an hydraulic component within the injector, wherein the improvement comprises a tubular debris diverter shield in the main passage, whereby a main flow passes axially within an inner wall of the tube and an auxiliary flow passes through a multiplicity of holes extending transversely from the inner wall to an outer wall, before delivery to the hydraulic component.
Dependencies are inferred from the claim text.