[Diy_efi] Fuel Pump PWM

[Mike]

Does anyone know the spring constant of the steel lines,
then apply this to the inside surface area of the steel
pipes over the length of high pressure fuel delivery,
include of course the fuel rail, sum this with the other
rubber/plastic devices and I'd expect the delta volume
would need to be factored into any control systems PID
algorithm to ensure stability and transient response...

rgds

mike



At 11:52 PM 5/8/2002 -0500, you wrote:
>The amount of compressibility practically is going to be 
>tied to how much rubber hose you have and how many 
>bubbles are in there.  The steel line and the liquid are 
>not going to be significant with any kind of flow.  I doubt 
>propagation time down the line is either, but increasing 
>the amount of rubber and vapor in the path IS.
>
>Bruce Roe
>
>On Mon, 05 Aug 2002 22:24:26 -0500 steve ravet 
><sravet at arm.com> writes:
>
>> Bernd Felsche wrote:
>> > If fluid isn't compressible, how does it transmit sound? :-)
>> > Yes, fuel *is* compressible.
>
>> > The longer the fuel line, the longer the propagation delay.
>
>> The propagation delay is the speed of sound.  I doubt that's 
>> worth considering.  The delay in building pressure is due to 
>> the compressibility of the fuel and the stretchy-ness of the 
>> fuel lines. 
>
>> Steve Ravet
>
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