Official Accusump Thread
02-06-2014, 09:57 PM
#16
Adam -
Do you remember a thread along time ago in a forum far far away (okay... here) that was about how by the time the oil pressure sensor "sees" the low pressure for the Accusump to actually trigger - that the low oil pressure has already "been in" the area of the bearings for long enough to cause damage?
Is anyone understanding the point that may have been making? Does anyone remember the thread?
Do you remember a thread along time ago in a forum far far away (okay... here) that was about how by the time the oil pressure sensor "sees" the low pressure for the Accusump to actually trigger - that the low oil pressure has already "been in" the area of the bearings for long enough to cause damage?
Is anyone understanding the point that may have been making? Does anyone remember the thread?
02-06-2014, 10:46 PM
#17
Drifting
I've wondered if an oil sump could be made to use a simple inertia switch to operate..
at the moment a specific lateral g force is met it opens and allows oil into the motor sump.
and then allows the aux sump to refill when that force is no longer present.
https://www.google.com/url?sa=t&rct=...60983673,d.eW0
at the moment a specific lateral g force is met it opens and allows oil into the motor sump.
and then allows the aux sump to refill when that force is no longer present.
https://www.google.com/url?sa=t&rct=...60983673,d.eW0
02-07-2014, 12:25 PM
#18
Cruisin'
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We are not an advertiser on here so we don't want to step on any toes. However, if anyone has any questions we would be more than happy to clarify. Email us info@cantonracingproducts.com
02-07-2014, 01:37 PM
#19
Rennlist Member
I like Colin's suggestion to have a logic solver that links rpm's and oil pressure as coincidental conditions thus ensuring the accusump does not release when pootling around, it should also help one to select a higher set pressure unit as the motor should be at full oil pressure by 3k rpm.
The only thing that would make me a bit wary about the value of this device is the fact that the oil pressure is dropping because the scoop has been exposed and the oil pump is presumably seeing a mix of oil and air [or whatever resides in the crankcase] and that is not going to do the engine any good at all. I presume this is why the accusump is not a perfect solution but can well understand why it is way better than nothing.
I suppose ideally you fit a pan spacer to accomodate the extra discharged volume to stop the crank sloshing around in oil..
No idea aabout the protocols here and whereas I can understand why potential vendors not sponsoring the list cannot advertise does that mean they cannot add their technical opinions to the forum? I can see why that may be a fine line but..?
Regards
Fred
The only thing that would make me a bit wary about the value of this device is the fact that the oil pressure is dropping because the scoop has been exposed and the oil pump is presumably seeing a mix of oil and air [or whatever resides in the crankcase] and that is not going to do the engine any good at all. I presume this is why the accusump is not a perfect solution but can well understand why it is way better than nothing.
I suppose ideally you fit a pan spacer to accomodate the extra discharged volume to stop the crank sloshing around in oil..
No idea aabout the protocols here and whereas I can understand why potential vendors not sponsoring the list cannot advertise does that mean they cannot add their technical opinions to the forum? I can see why that may be a fine line but..?
Regards
Fred
02-07-2014, 04:14 PM
#20
Cruisin'
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I like Colin's suggestion to have a logic solver that links rpm's and oil pressure as coincidental conditions thus ensuring the accusump does not release when pootling around, it should also help one to select a higher set pressure unit as the motor should be at full oil pressure by 3k rpm.
The only thing that would make me a bit wary about the value of this device is the fact that the oil pressure is dropping because the scoop has been exposed and the oil pump is presumably seeing a mix of oil and air [or whatever resides in the crankcase] and that is not going to do the engine any good at all. I presume this is why the accusump is not a perfect solution but can well understand why it is way better than nothing.
I suppose ideally you fit a pan spacer to accomodate the extra discharged volume to stop the crank sloshing around in oil..
No idea aabout the protocols here and whereas I can understand why potential vendors not sponsoring the list cannot advertise does that mean they cannot add their technical opinions to the forum? I can see why that may be a fine line but..?
Regards
Fred
The only thing that would make me a bit wary about the value of this device is the fact that the oil pressure is dropping because the scoop has been exposed and the oil pump is presumably seeing a mix of oil and air [or whatever resides in the crankcase] and that is not going to do the engine any good at all. I presume this is why the accusump is not a perfect solution but can well understand why it is way better than nothing.
I suppose ideally you fit a pan spacer to accomodate the extra discharged volume to stop the crank sloshing around in oil..
No idea aabout the protocols here and whereas I can understand why potential vendors not sponsoring the list cannot advertise does that mean they cannot add their technical opinions to the forum? I can see why that may be a fine line but..?
Regards
Fred
With the pressure switch there are ultimately two easy ways to do it. The easiest way that sometimes just doesn't work is to pick a valve that is below your idle pressure. This ensures that only when you pressure drops to that level will the Accusump discharge. This prevents any of the extra oil being in the pan and sloshing against the crank. As the pressure comes back the extra oil capacity will be pushed back into the Accusump.
The second way to do it is to pick the pressure below your normal operating pressure and only turn on the Accusump valve when you are hot lapping. This is the best option usually but also requires one more thing to remember which can be difficult.
The only other solution that we have seen was done by APR motorsports. We manufactured a private label version of our Accusumps that they then packaged with an ECU program that controls when the Accusump discharges. The system is probably the best scenario but is also super expensive and not exactly universal.
One other note, Pickup clearance is always super crucial and we have experienced some customers have issues when using oil pan spacers without a modified pickup tube. Essentially the spacer moved the pickup off the bottom of the pan further and makes it more likely to suck air.
02-07-2014, 05:54 PM
#21
Race Director
Canton
Thanks for your response. Since our cars run fairly high operating oil pressure, but normal idle pressures it makes it difficult to find a "system" to work properly.
I thought the ideal solution would be to have a RPM switch control the EPC valve on the accusump. So we could set the rpm that the accusump turns on and its automatic, so the driver can't forget. I know that I rarely drop below 3500rpm while racing....so I could set it at 3000 for a safety margin. A normal 928 oil pressure at 3000 would be at least 45psi, with most well above 70psi by that rpm.
Thanks for your response. Since our cars run fairly high operating oil pressure, but normal idle pressures it makes it difficult to find a "system" to work properly.
I thought the ideal solution would be to have a RPM switch control the EPC valve on the accusump. So we could set the rpm that the accusump turns on and its automatic, so the driver can't forget. I know that I rarely drop below 3500rpm while racing....so I could set it at 3000 for a safety margin. A normal 928 oil pressure at 3000 would be at least 45psi, with most well above 70psi by that rpm.
We have been yelled at before for trying to help without attempting to peddle our products so we are always cautious when posting on forums.
With the pressure switch there are ultimately two easy ways to do it. The easiest way that sometimes just doesn't work is to pick a valve that is below your idle pressure. This ensures that only when you pressure drops to that level will the Accusump discharge. This prevents any of the extra oil being in the pan and sloshing against the crank. As the pressure comes back the extra oil capacity will be pushed back into the Accusump.
The second way to do it is to pick the pressure below your normal operating pressure and only turn on the Accusump valve when you are hot lapping. This is the best option usually but also requires one more thing to remember which can be difficult.
The only other solution that we have seen was done by APR motorsports. We manufactured a private label version of our Accusumps that they then packaged with an ECU program that controls when the Accusump discharges. The system is probably the best scenario but is also super expensive and not exactly universal.
One other note, Pickup clearance is always super crucial and we have experienced some customers have issues when using oil pan spacers without a modified pickup tube. Essentially the spacer moved the pickup off the bottom of the pan further and makes it more likely to suck air.
With the pressure switch there are ultimately two easy ways to do it. The easiest way that sometimes just doesn't work is to pick a valve that is below your idle pressure. This ensures that only when you pressure drops to that level will the Accusump discharge. This prevents any of the extra oil being in the pan and sloshing against the crank. As the pressure comes back the extra oil capacity will be pushed back into the Accusump.
The second way to do it is to pick the pressure below your normal operating pressure and only turn on the Accusump valve when you are hot lapping. This is the best option usually but also requires one more thing to remember which can be difficult.
The only other solution that we have seen was done by APR motorsports. We manufactured a private label version of our Accusumps that they then packaged with an ECU program that controls when the Accusump discharges. The system is probably the best scenario but is also super expensive and not exactly universal.
One other note, Pickup clearance is always super crucial and we have experienced some customers have issues when using oil pan spacers without a modified pickup tube. Essentially the spacer moved the pickup off the bottom of the pan further and makes it more likely to suck air.
02-07-2014, 06:02 PM
#22
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Canton
Thanks for your response. Since our cars run fairly high operating oil pressure, but normal idle pressures it makes it difficult to find a "system" to work properly.
I thought the ideal solution would be to have a RPM switch control the EPC valve on the accusump. So we could set the rpm that the accusump turns on and its automatic, so the driver can't forget. I know that I rarely drop below 3500rpm while racing....so I could set it at 3000 for a safety margin. A normal 928 oil pressure at 3000 would be at least 45psi, with most well above 70psi by that rpm.
Thanks for your response. Since our cars run fairly high operating oil pressure, but normal idle pressures it makes it difficult to find a "system" to work properly.
I thought the ideal solution would be to have a RPM switch control the EPC valve on the accusump. So we could set the rpm that the accusump turns on and its automatic, so the driver can't forget. I know that I rarely drop below 3500rpm while racing....so I could set it at 3000 for a safety margin. A normal 928 oil pressure at 3000 would be at least 45psi, with most well above 70psi by that rpm.
02-07-2014, 06:03 PM
#23
Rennlist Member
Canton
Thanks for your response. Since our cars run fairly high operating oil pressure, but normal idle pressures it makes it difficult to find a "system" to work properly.
I thought the ideal solution would be to have a RPM switch control the EPC valve on the accusump. So we could set the rpm that the accusump turns on and its automatic, so the driver can't forget. I know that I rarely drop below 3500rpm while racing....so I could set it at 3000 for a safety margin. A normal 928 oil pressure at 3000 would be at least 45psi, with most well above 70psi by that rpm.
Thanks for your response. Since our cars run fairly high operating oil pressure, but normal idle pressures it makes it difficult to find a "system" to work properly.
I thought the ideal solution would be to have a RPM switch control the EPC valve on the accusump. So we could set the rpm that the accusump turns on and its automatic, so the driver can't forget. I know that I rarely drop below 3500rpm while racing....so I could set it at 3000 for a safety margin. A normal 928 oil pressure at 3000 would be at least 45psi, with most well above 70psi by that rpm.
02-07-2014, 10:02 PM
#24
Rennlist Member
Thread Starter
Is the EPC a one way valve?
Lets say a low pressure event happens, the pressure threshold for the valve is reached, and the EPC valve opens. Because the pressure on the "engine" side of the EPC valve is lower than the (compressed) air pressure on the pressurized side of the cannister, the "piston" in the cannister pushes all the oil out into the oiling system. Once the low pressure event is over, and the engine starts pressuring the oiling system again, oil will start flowing back into the accusump. But what determines when oil stops flowing back into the accusump? Is it when the EPC valve threshold is exceeded (when the oil pressure re-stabilizes) and the valve closes? Or does the accusump (EDIT:should read "oil pump") continue to fill the cannister (i.e. one way valve). It doesn't seem like the cannister could refill in time if the oil pressure stabilizes quickly after having been low long enough to empty the cannister.
Lets say a low pressure event happens, the pressure threshold for the valve is reached, and the EPC valve opens. Because the pressure on the "engine" side of the EPC valve is lower than the (compressed) air pressure on the pressurized side of the cannister, the "piston" in the cannister pushes all the oil out into the oiling system. Once the low pressure event is over, and the engine starts pressuring the oiling system again, oil will start flowing back into the accusump. But what determines when oil stops flowing back into the accusump? Is it when the EPC valve threshold is exceeded (when the oil pressure re-stabilizes) and the valve closes? Or does the accusump (EDIT:should read "oil pump") continue to fill the cannister (i.e. one way valve). It doesn't seem like the cannister could refill in time if the oil pressure stabilizes quickly after having been low long enough to empty the cannister.
Last edited by atb; 02-11-2014 at 11:16 AM.
02-08-2014, 01:46 AM
#25
Rennlist Member
But what determines when oil stops flowing back into the accusump? Is it when the EPC valve threshold is exceeded (when the oil pressure re-stabilizes) and the valve closes? Or does the accusump continue to fill the cannister (i.e. one way valve). It doesn't seem like the cannister could refill in time if the oil pressure stabilizes quickly after having been low long enough to empty the cannister.
This is why I suspect such a system perhaps needs a logic based controller so that when the oil pressure recovers from "the event" the valve stays open for an amount of time until it can fill, then it closes. For all I know the valve may indeed have this feature built in triggered by a mechanical limit switch that flips when the unit is full.
The accusump device will have a certain residence time to empty and logic suggests it will take longer to fill than it does to empty. Obviously the unit has to be specifiied to give the oil pressure support time interval needed for a specific vehicle for a specific event time- say 10 seconds with capacity determined by the specific oil flow. Then of course when it fills one does not want to starve the bearings as it fills so presumably the fill rate may well be controlled by having a different flow path controlled by a check valve to allow filling at a lesser rate but taking longer.
Then of course one has to ask the question as to whether there is a user specific scenario wherein one event needing oil pressure support can occur immediately after the previous one is over and whether the system can then cope.
Doubtless the clever folks who design these things take such obvious considerations into account even though it may not be obvious as to how it is done at first glance. Such would explain why such control units are not cheap.
Regards
Fred
02-08-2014, 04:18 AM
#26
Rennlist Member
Thread Starter
Fred, your observations lead to my next question. My understanding is that the accusump canister uses pressurized air to force the oil out of the canister. I haven't seen a cut away, so I don't know if a 3 qt canister refers to the volume of the canister (which I believe would include the chamber where the pressurized air is stored) or just the oil capacity. The canister has a slide that separates the oil from the pressurized air which is pumped in through a Schraeder valve. On the one hand, you would want a lot of air pressure to ensure maximum oil delivery over the shortest amount of time during a low oil pressure event. On the others hand, when it comes to refilling the accusump, the engine oil pump now needs to fight the resistance of the air pressure in the canister in order to refill it. So how does one determine the right amount of air pressure to charge the canister with to get a quick response time from the accusump, but also allows for reasonably quick re-filling?
02-08-2014, 05:37 AM
#27
Rennlist Member
Adam,
We use similar devices in our industry to dampen out pulses- sometimes they have a bladder that expands and contracts and as you say, maybe there is a piston inside the cylinder to segregate the oil from the air. If it is a piston then the pressure has to be such that when the oil is fully evacuated the pressure on the air side has to equal or exceed the set point of the pressure switch assuming I understand the geometry correctly. Thus if the cylinder chambers were 3 litres on both sides of the piston [1:1 ratio], to drive out the oil and maintain 5barg at the end of stroke the starting pressure on the air side would have to be 10 barg minimum. If the volumetric ratio was 3:1, the pressure would have to be 4 times higher -i.e. 20 barg [approx 300 psig] assuming Boyle's law still works. At the moment I have no idea what such cylinders are mechanically rated for but trust you get the concept. I doubt they would be designed to go above 20 barg but remember hydraulic cylinders get to some pretty heady pressures- but that is hydraulic- not pneumatic.
Doubtless the manufacturer's will have tables that explain all this.
Regards
Fred
We use similar devices in our industry to dampen out pulses- sometimes they have a bladder that expands and contracts and as you say, maybe there is a piston inside the cylinder to segregate the oil from the air. If it is a piston then the pressure has to be such that when the oil is fully evacuated the pressure on the air side has to equal or exceed the set point of the pressure switch assuming I understand the geometry correctly. Thus if the cylinder chambers were 3 litres on both sides of the piston [1:1 ratio], to drive out the oil and maintain 5barg at the end of stroke the starting pressure on the air side would have to be 10 barg minimum. If the volumetric ratio was 3:1, the pressure would have to be 4 times higher -i.e. 20 barg [approx 300 psig] assuming Boyle's law still works. At the moment I have no idea what such cylinders are mechanically rated for but trust you get the concept. I doubt they would be designed to go above 20 barg but remember hydraulic cylinders get to some pretty heady pressures- but that is hydraulic- not pneumatic.
Doubtless the manufacturer's will have tables that explain all this.
Regards
Fred
02-10-2014, 10:05 AM
#28
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Is the EPC a one way valve?
Lets say a low pressure event happens, the pressure threshold for the valve is reached, and the EPC valve opens. Because the pressure on the "engine" side of the EPC valve is lower than the (compressed) air pressure on the pressurized side of the cannister, the "piston" in the cannister pushes all the oil out into the oiling system. Once the low pressure event is over, and the engine starts pressuring the oiling system again, oil will start flowing back into the accusump. But what determines when oil stops flowing back into the accusump? Is it when the EPC valve threshold is exceeded (when the oil pressure re-stabilizes) and the valve closes? Or does the accusump continue to fill the cannister (i.e. one way valve). It doesn't seem like the cannister could refill in time if the oil pressure stabilizes quickly after having been low long enough to empty the cannister.
Lets say a low pressure event happens, the pressure threshold for the valve is reached, and the EPC valve opens. Because the pressure on the "engine" side of the EPC valve is lower than the (compressed) air pressure on the pressurized side of the cannister, the "piston" in the cannister pushes all the oil out into the oiling system. Once the low pressure event is over, and the engine starts pressuring the oiling system again, oil will start flowing back into the accusump. But what determines when oil stops flowing back into the accusump? Is it when the EPC valve threshold is exceeded (when the oil pressure re-stabilizes) and the valve closes? Or does the accusump continue to fill the cannister (i.e. one way valve). It doesn't seem like the cannister could refill in time if the oil pressure stabilizes quickly after having been low long enough to empty the cannister.
02-10-2014, 10:07 AM
#29
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Fred, your observations lead to my next question. My understanding is that the accusump canister uses pressurized air to force the oil out of the canister. I haven't seen a cut away, so I don't know if a 3 qt canister refers to the volume of the canister (which I believe would include the chamber where the pressurized air is stored) or just the oil capacity. The canister has a slide that separates the oil from the pressurized air which is pumped in through a Schraeder valve. On the one hand, you would want a lot of air pressure to ensure maximum oil delivery over the shortest amount of time during a low oil pressure event. On the others hand, when it comes to refilling the accusump, the engine oil pump now needs to fight the resistance of the air pressure in the canister in order to refill it. So how does one determine the right amount of air pressure to charge the canister with to get a quick response time from the accusump, but also allows for reasonably quick re-filling?
02-10-2014, 10:55 AM
#30
Rennlist Member
Thread Starter
Thanks for the responses, it helps in better understanding your product.
I can understand the need to have the pressure switch as part of the valve for simplicity/packaging purposes, but I'm wondering if there is a way to separate the two. It would seem that ideally, you would want to read the pressure drop before the oil pump, but release the oil after the oil filter.
I can understand the need to have the pressure switch as part of the valve for simplicity/packaging purposes, but I'm wondering if there is a way to separate the two. It would seem that ideally, you would want to read the pressure drop before the oil pump, but release the oil after the oil filter.