Re: fuel system question

["checksix3 <jetjock11@xxxx>" <jetjock11@xxxx>]

More than you probaly wanted to know but an accumulator as used in 
this sense is, by definition, a hydraulic term. Commonly used in 
hydraulic systems (your fuel system is a hydraulic system), 
accumulators are devices used to store (or accumulate) pressure when 
the main pressure pump is off. They do this in many ways but are 
usually a spring loaded volume that pressurizes the fluid in the 
system. The system requires chceck valving or other means to make it 
tight or the accumulator won't do it's job effectively

Your fuel injection system needs to remain pressurized after the fuel 
pump stops to avoid vapor formation and hard starting. The 
accumulator does this for you. I'll leave it to others to describe 
exactly how it does that but suffice to say it works in conjuction 
with other check valving and seals in your fuel system to keep the 
fuel pressure at a certain value. There is a spec for this "rest" 
pressure in your service manual, along with the minimum time the 
system should hold it for.

Btw, don't ever open any hydraulic accumulator up without restraining 
it, depending on the diameter of the diaphram or piston there is 
tremendous energy in the srping. The bigger the system pressure, the 
bigger the diameter of the unit or strength of the spring needs to 
be. (Force = Pressure x Area in fluid engineering.) I've seen a Bosch 
unit that, when cut open on a lathe, fired the internal parts and 
spring right through a wooden door. It has a serious spring in there, 
for those who've seen the inside of the Bosch unit you know what I 
mean. 


--- In dmcnews@xxxxxxxxxxxxxxx, id <ionicdesign@xxxx> wrote:
> i have a stupid question and i should know this but what does a 
Fuel Accumulator do
> exactly?
> 
> mark