High pressure unit fuel injector with timing chamber pressure control
US4986472A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 5, 1989 |
| Grant date | Jan 22, 1991 |
| Priority date | — |
| Expiry date | Sep 5, 2009 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02M59/30
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
A fuel injector includes an injector housing having a plunger assembly disposed within a central axial bore and including a lower plunger, an intermediate plunger, and an upper plunger. The lower plunger reciprocates within the central bore to meter a variable quantity of fuel during downward portions of the reciprocating motion. A timing spring is wound around the upper portion of the lower plunger to bias the lower plunger upwardly. A timing chamber formed between the upper and intermediate plungers receives timing fluid to create a hydraulic link between the plungers. Timing fluid exits the timing chamber through a central passage, which may have a reduced area regulating orifice, formed through the intermediate plunger, which is ordinarily closed by a valve mechanism. The valve mechanism is acted upon in part by the timing spring. To improve the pressure regulation using a higher spring load and to accommodate a larger area drainage passage, a valve spring biases closed the passage. The force provided by the valve spring is predetermined to open the valve mechanism and drain timing fluid when the timing fluid pressure exceeds the maximum pressure during injection. After injecti…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.