I'm thinking of just active above 3krpm.?
Also what output / assign to use?
Issues I see are:
If you use the electronic valve with just ignition controlling at idle the AS will dump its contents to sump and overfilling,(probably slowly due to small differential but still it would) along with that comes aeration as crank sloshing oil.
The epc valve still makes no sense.
We could map activation to follow rpm so if oil pressure is below minimum for x rpm activate but how would you manage charging?
accusump strategy
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pat
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Re: accusump strategy
The simplest strategy to use to activate an Accusump valve over 3000 RPM would be one of the "Engine Speed Controlled" outputs, you could configure this to turn on at 3000 RPM.
There are a few things to note with regard to the Accusump though that mean a dedicated strategy would probably be better :
1) It is often useful to open the valve before cranking. This allows the oil galleries to fill from the residual pressure in the Accusump. This is almost as good in terms of protecting the engine from damage due to dry bearings during cranking as the oil primer kit I used to offer - the primer kit has the advantage that it cannot "run out" of oil like an Accusump
2) The purpose of the Accusump is to maintain oil pressure in the event of oil surge. In order to fulfil this function properly, it has to "work" the oil - that is oil must constantly be entering and leaving the Accusump when in operation - if this was not the case then the viscosity of the oil reserve would be significantly greater than the oil that is in the bearings at the point that the surge condition happens, so oil could drain out of the bearings faster than it can re-enter from the reservoir. This isn't a problem when the engine is cold because the oil in the bearings is cold too, so it drains less rapidly. In a nutshell, then, one should NOT use it as an emergency reservoir but more as a working part of the oil delivery system, much the same way as a hydraulic dampener works.
3) It is wise to refill the Accusump just before stopping the engine. Any strategy that allows the valve to open at 3k would not prove useful for refilling prior to stop because often it is necessary to rev past 4k to get enough oil pressure to fill it. Instead it would be sensible to use TPS gating with hysteresis and timeout to open the valve when it is time "to do some work" and to close it again when the propensity to surge goes away (perhaps even using vehicle speed gating - you don't normally get oil surge stood still).
4) Trying to implement a "closed loop" oil pressure control system based on an electrically controlled feed from a reservoir is both an excercise in futility and irresponsible toward an otherwise healthy engine. If you ever do an analysis on the bearing loading you soon see that the oil pressure exerts only a minute amount of force - the bearings we are trying to protect are hydrodynamic and the dynamic pressure is orders of magnitude greater than the "oil pressure". The sole purpose of the oil pressure is to ensure the integrity of the hydrodynamic barrier by continuously replenishing that tiny precious film of oil - when that breaks down it is already too late to do anything about it, it's time to pull the engine apart. Adding the delay associated with the latency of the oil pressure sensor, the A/D converter, the strategy service code, updating the output register, the reaction time of the control valve yields an an unneccessary and unacceptable delay to something that will work just as well without the added complication. Yes, some strategy code to intelligently decide when the valve should be open is worth doing but going closed loop on engine oil pressure is not sensible.
Hope this makes sense,
Pat.
There are a few things to note with regard to the Accusump though that mean a dedicated strategy would probably be better :
1) It is often useful to open the valve before cranking. This allows the oil galleries to fill from the residual pressure in the Accusump. This is almost as good in terms of protecting the engine from damage due to dry bearings during cranking as the oil primer kit I used to offer - the primer kit has the advantage that it cannot "run out" of oil like an Accusump
2) The purpose of the Accusump is to maintain oil pressure in the event of oil surge. In order to fulfil this function properly, it has to "work" the oil - that is oil must constantly be entering and leaving the Accusump when in operation - if this was not the case then the viscosity of the oil reserve would be significantly greater than the oil that is in the bearings at the point that the surge condition happens, so oil could drain out of the bearings faster than it can re-enter from the reservoir. This isn't a problem when the engine is cold because the oil in the bearings is cold too, so it drains less rapidly. In a nutshell, then, one should NOT use it as an emergency reservoir but more as a working part of the oil delivery system, much the same way as a hydraulic dampener works.
3) It is wise to refill the Accusump just before stopping the engine. Any strategy that allows the valve to open at 3k would not prove useful for refilling prior to stop because often it is necessary to rev past 4k to get enough oil pressure to fill it. Instead it would be sensible to use TPS gating with hysteresis and timeout to open the valve when it is time "to do some work" and to close it again when the propensity to surge goes away (perhaps even using vehicle speed gating - you don't normally get oil surge stood still).
4) Trying to implement a "closed loop" oil pressure control system based on an electrically controlled feed from a reservoir is both an excercise in futility and irresponsible toward an otherwise healthy engine. If you ever do an analysis on the bearing loading you soon see that the oil pressure exerts only a minute amount of force - the bearings we are trying to protect are hydrodynamic and the dynamic pressure is orders of magnitude greater than the "oil pressure". The sole purpose of the oil pressure is to ensure the integrity of the hydrodynamic barrier by continuously replenishing that tiny precious film of oil - when that breaks down it is already too late to do anything about it, it's time to pull the engine apart. Adding the delay associated with the latency of the oil pressure sensor, the A/D converter, the strategy service code, updating the output register, the reaction time of the control valve yields an an unneccessary and unacceptable delay to something that will work just as well without the added complication. Yes, some strategy code to intelligently decide when the valve should be open is worth doing but going closed loop on engine oil pressure is not sensible.
Hope this makes sense,
Pat.
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mapping dabbler
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Re: accusump strategy
cheers pat.
hmm food for thought.
may need to locate cylinder engine bay side to reduce oil line lengths and maybe have the cylinder heated? lag the short pipe from oil gallery connection point to the AS
hmm food for thought.
may need to locate cylinder engine bay side to reduce oil line lengths and maybe have the cylinder heated? lag the short pipe from oil gallery connection point to the AS