Hydraulically actuated fuel injector including a pilot operated spool valve assembly and hydraulic system using same

Patent · Tue Jan 01 00:00:00 EST 2002

OSTI ID:874271

Shafer, Scott F ^[1]

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1. Morton, IL

The present invention relates to hydraulic systems including hydraulically actuated fuel injectors that have a pilot operated spool valve assembly. One class of hydraulically actuated fuel injectors includes a solenoid driven pilot valve that controls the initiation of the injection event. However, during cold start conditions, hydraulic fluid, typically engine lubricating oil, is particularly viscous and is often difficult to displace through the relatively small drain path that is defined past the pilot valve member. Because the spool valve typically responds slower than expected during cold start due to the difficulty in displacing the relatively viscous oil, accurate start of injection timing can be difficult to achieve. There also exists a greater difficulty in reaching the higher end of the cold operating speed range. Therefore, the present invention utilizes a fluid evacuation valve to aid in displacement of the relatively viscous oil during cold start conditions.

• Research Organization: Caterpillar Inc., Deerfield, IL (United States)
• DOE Contract Number: FC05-97OR22605
• Assignee: Caterpillar Inc. (Peoria, IL)
• Patent Number(s): US 6354270
• OSTI ID: 874271
• Country of Publication: United States
• Language: English

Related Subjects

hydraulically
actuated
fuel
injector
including
pilot
operated
spool
valve
assembly
hydraulic
relates
systems
injectors
solenoid
driven
controls
initiation
injection
event
cold
start
conditions
fluid
typically
engine
lubricating
oil
viscous
difficult
displace
drain
path
defined
past
responds
slower
expected
due
difficulty
displacing
accurate
timing
achieve
exists
reaching
operating
speed
range
utilizes
evacuation
displacement
fuel injector
systems including
/123/137/239/