Hydraulically-actuated fuel injector with variable rate return spring
US5871155A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 10, 1997 |
| Grant date | Feb 16, 1999 |
| Priority date | — |
| Expiry date | Jun 10, 2017 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02M2200/50
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
A hydraulically actuated fuel injector includes an injector body defining an actuation fluid chamber that opens to an actuation fluid drain, an actuation fluid inlet and a piston bore, and further defining a nozzle chamber that opens to a plunger bore and a nozzle outlet. A control valve, positioned in the injector body, has a first position that opens the actuation fluid inlet and closes the actuation fluid drain, and a second position that closes the actuation fluid inlet and opens the actuation fluid drain. A piston, positioned in the piston bore. A plunger, positioned in the plunger bore, is moveable between an upper position and a lower position. A needle valve member, positioned in the nozzle chamber, is moveable between an open position in which the nozzle outlet is open and a closed position in which the nozzle outlet is blocked. A portion of the plunger bore and the plunger define a fuel pressurization chamber that opens to the nozzle chamber. A variable rate return spring biases the piston and plunger toward their retracted positions. The variable rate return spring has a relatively low spring rate when the piston is a first distance away from its retracted position and h…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.