各位大佬好 这个是我最近设计的xs650多多指教

So the pressure will continue to build until something gives... and something will give.
I didn't go into my concerns for this because I think what will give well before the metal in the pump is the rubber in the seals. They are going to be pop off valves.
 
So the net flow to the engine will be zero... both sides have equal pressure.
No the pump would still create pressure. At atmosphere the pressure is equal on each side. The breather venting to the tank will not change the pressure differential between the crankcase and the oiling passages.
 
The breather venting to the tank will not change the pressure differential between the crankcase and the oiling passages.
It would be the (vent) pressure inside the tank forcing oil into the oil passages. So the pressure inside the passages will be the same as the tank pressure.
Just for example purposes lets say the tank built up 10psi of pressure from the crankcase vent. That 10psi forces the oil into the passageways.... the passageways are pressurized to 10psi. But..... that same 10psi is inside the crankcase because they are linked through the breather tube. Inside the crankcase happens to be the outlet of the oil passages. There's zero pressure differential... no oil will flow until the tank fills up with oil and the pump pressure can exert a force greater than what's in the crankcase.
 
It would be the (vent) pressure inside the tank forcing oil into the oil passages. So the pressure inside the passages will be the same as the tank pressure.
Just for example purposes lets say the tank built up 10psi of pressure from the crankcase vent. That 10psi forces the oil into the passageways.... the passageways are pressurized to 10psi. But..... that same 10psi is inside the crankcase because they are linked through the breather tube. Inside the crankcase happens to be the outlet of the oil passages. There's zero pressure differential... no oil will flow until the tank fills up with oil and the pump pressure can exert a force greater than what's in the crankcase.
Exactly 10 on each side of pump. The pump creates pressure, ergo pressure differential, ergo flow. 10psi+pump addition=flow.
 
Exactly 10 on each side of pump. The pump creates pressure, ergo pressure differential, ergo flow. 10psi+pump addition=flow.

2 containers with a common pipe between them. Let's use a 10psi pump to pump from container B into container A.
What's the pressure in the "common" pipe?
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Thinking you'd have to have a float controlled atmospheric port in that oil tank
 
Let's add a filter and "passageways."
Same question: What's the pressure in the "common" pipe?

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2 containers with a common pipe between them. Let's use a 10psi pump to pump from container B into container A.
What's the pressure in the "common" pipe?
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There is no common pipe. Pressure on each side of the pump is the same therefore the pump moves oil. All the the pump in the 650s does is move oil. The small holes in the discharge side causes the pressure depending on the orifice size on the pump discharge side and the volume capabilities of the pump. Head pressure (on a 650 not much) and the pumps lift ability also play into the pressure developed. We need a hydraulic engineer to wade in here and set us straight.
You are showing the pump above the fluid level of the pump. That can and will make a difference. Also the filter will make a difference. Need flow data on the filter and the height of the pump above the fluid. GPM of the pump would also be nice. All things being equal if the discharge side is equal to the suction side as your pic shows there will be no pressure created only flow. You drew a transfer pump.
 
Actually I should have said a recirc pump.
 
You drew a transfer pump.
Bingo. The pump is transferring fluid (under pressure) from container B (crankcase sump) to container A (oil tank). The pressure in the common pipe (yes there is one) is only the difference in head pressure between the 2 containers. Since the difference in the "heads" is measured in inches, the difference in pressure will be very small.... likely much less than 1 psi.

Now let's close it off and add blowby as a variable. It still works as exactly the same "transfer" pump. We can add 100psi of blowby and it won't change the fact that all we're gonna see in the "common pipe" is the difference in head pressure.


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Bingo. The pump is transferring pressure from container B (crankcase sump) to container A (oil tank).
No it's only transferring fluid. Since the the pressure on each side is the same there is no pressure increase. If there was a restriction on the discharge side there would be a pressure increase in the discharge pipe from the pump to the restriction.
 
Go back and read it again... I edited it right after I posted
 
Flow has to have restriction to create pressure. Fluid power 101. No restriction just moving fluid. The small orifices in the 650s oil delivery system cause the small amount of pressure the pump develops. The reason for the restrictions in the 650s is not to develop pressure it's to make sure oil gets to where it needs to get to. It's a volume system not a pressure system.
Like I said we need a Engineer to set either myself or you straight. @MaxPete don't you deal with the oily stuff?
 
OK Regarding pressure and flow
I have worked with those things in Excavators and Air conditioning
if you refer to a Description of the system I can give it a try.
Depending on type of pump it is different
If it is a Centrifugal type as in water pump or a Fix displacement pump it is different

Jims # 73 has connection between both sides A + B Both above surface and under surface
.And then no Pressure difference. Those will level out
The pump in itself has a pressure difference between in and out otherwise it will not pump the fluid
And if the Common pipe can transfer more or equal that what the pump gives
It will circulate fluid without pressure difference between A and B
If I get it right here this late.
Please give more info if this is wrong I have not read earlier posts.
 
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