Patent ID: 9644589
Date: 2017-05-09
CPC Classifications: F02D,F02M

Claim:
1. 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 tube wall with a multiplicity of individual radial bore holes passing entirely through the tube wall; wherein the body comprises an upper portion containing the control valve and an upper portion of the fuel supply passage, a lower portion containing the injector valve and a lower portion of the fuel supply passage, and a distinct central portion having upper and lower surfaces rigidly trapped between the upper and lower portions of the body and a shield chamber fluidly connecting the upper and lower portions of the fuel supply passage; wherein the debris shield is situated in the shield chamber; and wherein the tube has opposed ends extending from the upper to the lower surface of the central portion of the body, and the tube is fixed to the body in longitudinal compression between the upper and lower portions of the body, by compressive engagement with the lower surface of the upper portion and compressive engagement with the upper surface of the lower portion.