AISIN WATER PUMP PASSAGE SURFACE ROUGHness
05-03-17, 01:13 PM
#16
Lexus Champion
Thread Starter
However, quite possibly the thermostat is open while the car is being drivn to allow coolant to circulate through the engine blockand radiator...
The Aisin pump is mass-produced.
Is there room for improvement? It appears so...
Can Aisin do it? Definitely.
Will they do it? Probably not...
In fact Aisin has not responded to me regarding this post.
Last edited by YODAONE; 05-03-17 at 01:17 PM.
05-03-17, 01:28 PM
#17
Lexus Champion
Thread Starter
Extrude honing would radius the internal sharp transitions and remove a lot of internal.casting flash in the engine block coolant passages. Probably worth a few H.P. but understand why the OEM.does not do this...
While good for coolant flow, might not want Extrude honing mirror finish inside these passages... for heat transfer considerations. Must be a happy medium...but secondary extrude honing would certainly help.
05-03-17, 03:46 PM
#18
Lexus Champion
Thread Starter
Someone out there with information on how coolant is routed through the block?
It seems that the water pump and cooling system in general is an energy hog which merits more attention from auto OEM's
I like electric water pumps because they can be run at speeds independent of engine operation...and here it is apparent that before engine warms to operating temperature the thermostat is closed, thus the water pump is not only placing an increased load on the engine, but not contributing anything... I mean auto OEMs employed clutches on the radiator fans to reduce parasitic drag on the engine since about 1960...why not on the water pump?
The one thing I do not like about engine driven water pumps is when the engine is turned off, they stop circulating coolant and the heat already imparted into the block has no where to go..so the engine cooks for a few minutes...
An electric pump could circulate coolant for a few minutes to dissipate heat in tandem with OEM electric fans to prolong engine life.(some electric fans continue to operate after an engine is shut down for this very reason)
That could present an interesting project for our cars...a time-delay relay that operates the electroc fans for a few minutes so the underhood components do not cook after shutdown.
05-03-17, 03:55 PM
#19
So block the dang vacuum and see that the load is DECREASED. And the unloaded motor will speed up! Just try it.
Last edited by dicer; 05-03-17 at 03:59 PM.
05-04-17, 09:40 AM
#20
Dicer is correct, with a centrifugal pump the power output is only (actually mostly, there are small frictional effects) a function of flow rate assuming a constant RPM. The more flow you reduce by throttling the discharge of the pump, the less power it will use. This is unlike a positive displacement pump wherein as you block the discharge the flow rate remains the same and pressure differential/power consumption increases. So by smoothing out the casting and reducing flow resistance, you have essentially increased the flow rate and increased the amount of power draw of the pump (albeit negligible).
When the thermostat is closed, the pump is still circulating coolant through the block to maintain and even temperature distribution around the engine block. It also pumps coolant through the heater if you have your heat on. As the engine warms up the thermostat opens and instead of going through the coolant bypass the coolant is routed through the radiator.
The biggest advantage to an electric pump is that it can be operated at its highest efficiency RPM regardless of engine speed. Other than that, you are wasting energy by converting from mechanical to electrical and then back from electrical to mechanical again. Most water pumps do not move enough coolant at low speeds and tend to cavitate at high speeds, neither of which are optimal conditions. Electric pumps allow you to run the pump in its sweet spot as far as flow is concerned, but you likely will not reduce your HP usage due to the conversion losses.
When the thermostat is closed, the pump is still circulating coolant through the block to maintain and even temperature distribution around the engine block. It also pumps coolant through the heater if you have your heat on. As the engine warms up the thermostat opens and instead of going through the coolant bypass the coolant is routed through the radiator.
The biggest advantage to an electric pump is that it can be operated at its highest efficiency RPM regardless of engine speed. Other than that, you are wasting energy by converting from mechanical to electrical and then back from electrical to mechanical again. Most water pumps do not move enough coolant at low speeds and tend to cavitate at high speeds, neither of which are optimal conditions. Electric pumps allow you to run the pump in its sweet spot as far as flow is concerned, but you likely will not reduce your HP usage due to the conversion losses.
Last edited by cyfi66; 05-04-17 at 09:47 AM.
05-04-17, 03:58 PM
#21
Dicer is correct, with a centrifugal pump the power output is only (actually mostly, there are small frictional effects) a function of flow rate assuming a constant RPM. The more flow you reduce by throttling the discharge of the pump, the less power it will use. This is unlike a positive displacement pump wherein as you block the discharge the flow rate remains the same and pressure differential/power consumption increases. So by smoothing out the casting and reducing flow resistance, you have essentially increased the flow rate and increased the amount of power draw of the pump (albeit negligible).
When the thermostat is closed, the pump is still circulating coolant through the block to maintain and even temperature distribution around the engine block. It also pumps coolant through the heater if you have your heat on. As the engine warms up the thermostat opens and instead of going through the coolant bypass the coolant is routed through the radiator.
The biggest advantage to an electric pump is that it can be operated at its highest efficiency RPM regardless of engine speed. Other than that, you are wasting energy by converting from mechanical to electrical and then back from electrical to mechanical again. Most water pumps do not move enough coolant at low speeds and tend to cavitate at high speeds, neither of which are optimal conditions. Electric pumps allow you to run the pump in its sweet spot as far as flow is concerned, but you likely will not reduce your HP usage due to the conversion losses.
When the thermostat is closed, the pump is still circulating coolant through the block to maintain and even temperature distribution around the engine block. It also pumps coolant through the heater if you have your heat on. As the engine warms up the thermostat opens and instead of going through the coolant bypass the coolant is routed through the radiator.
The biggest advantage to an electric pump is that it can be operated at its highest efficiency RPM regardless of engine speed. Other than that, you are wasting energy by converting from mechanical to electrical and then back from electrical to mechanical again. Most water pumps do not move enough coolant at low speeds and tend to cavitate at high speeds, neither of which are optimal conditions. Electric pumps allow you to run the pump in its sweet spot as far as flow is concerned, but you likely will not reduce your HP usage due to the conversion losses.
05-04-17, 05:57 PM
#22
Lexus Champion
Thread Starter
Dicer is correct, with a centrifugal pump the power output is only (actually mostly, there are small frictional effects) a function of flow rate assuming a constant RPM. The more flow you reduce by throttling the discharge of the pump, the less power it will use. This is unlike a positive displacement pump wherein as you block the discharge the flow rate remains the same and pressure differential/power consumption increases. So by smoothing out the casting and reducing flow resistance, you have essentially increased the flow rate and increased the amount of power draw of the pump (albeit negligible).
When the thermostat is closed, the pump is still circulating coolant through the block to maintain and even temperature distribution around the engine block. It also pumps coolant through the heater if you have your heat on. As the engine warms up the thermostat opens and instead of going through the coolant bypass the coolant is routed through the radiator.
The biggest advantage to an electric pump is that it can be operated at its highest efficiency RPM regardless of engine speed. Other than that, you are wasting energy by converting from mechanical to electrical and then back from electrical to mechanical again. Most water pumps do not move enough coolant at low speeds and tend to cavitate at high speeds, neither of which are optimal conditions. Electric pumps allow you to run the pump in its sweet spot as far as flow is concerned, but you likely will not reduce your HP usage due to the conversion losses.
When the thermostat is closed, the pump is still circulating coolant through the block to maintain and even temperature distribution around the engine block. It also pumps coolant through the heater if you have your heat on. As the engine warms up the thermostat opens and instead of going through the coolant bypass the coolant is routed through the radiator.
The biggest advantage to an electric pump is that it can be operated at its highest efficiency RPM regardless of engine speed. Other than that, you are wasting energy by converting from mechanical to electrical and then back from electrical to mechanical again. Most water pumps do not move enough coolant at low speeds and tend to cavitate at high speeds, neither of which are optimal conditions. Electric pumps allow you to run the pump in its sweet spot as far as flow is concerned, but you likely will not reduce your HP usage due to the conversion losses.
Based on the arguments presented here, then as the fluid flow dynamics improve...better water inlet design (see 2001 LS430 vs 2000LS400 water inlet images in this post) casting flash, sharp edges and roughness removed from the passageways is going to require more power?
So rough surfaces in air or coolant passageways is more conducive to fluid or airflow?.
Let me think about that....
I believe OEM's could do a much better job on cooling system design..every hose bend, every sharp transition where the hoses affix to the radiator or thermostat husing, internal passages in the radiator, cylinder head or engine block all add up to increase resistance to coolant flow, thus more or less engine power is required to flow coolant.. .casting passageway roughness aside
It's just physics.
05-04-17, 08:55 PM
#23
...Based on the arguments presented here, then as the fluid flow dynamics improve...better water inlet design (see 2001 LS430 vs 2000LS400 water inlet images in this post) casting flash, sharp edges and roughness removed from the passageways is going to require more power?
So rough surfaces in air or coolant passageways is more conducive to fluid or airflow?.
Let me think about that....
So rough surfaces in air or coolant passageways is more conducive to fluid or airflow?.
Let me think about that....
With an electric pump, you could make the decision to pump at a certain rate, so reducing system drag would then reduce power required to pump. But with our pumps, it is not a variable you can control.
If the system were optimized to reduce drag, then a new, lower power impeller could be substituted and still meet cooling requirements. Because drag was reduced, this new impeller (e.g., smaller or fewer blades, or a bigger pulley so it spins slower) would be able to provide the same flow rate with less power draw. Flow rate is the thing the cooling system needs - does not care about power or pressure drop.
But for the same pump, lower drag increases flow, which increases power draw, which comes from the crank shaft via the timing belt.
05-04-17, 09:04 PM
#24
Here's a kind of funny way to think about power required by a centrifugal pump - the merry-go-round analogy:
http://cr4.globalspec.com/thread/761...r-Current-Draw
shamelessly copying from that:
"Now for a Centrifugal pump, think of one of those push type merry-go-round play structures at the playground. Imagine 20 children loaded up on top of it, all the way out to the edges. Now imagine trying to spin it. It's going to be difficult, right? So imagine an endless flow of children dropping into the center while it is spinning, and the children on the outside edges falling off at the same rate. The work you have to do to in order to keep it spinning is constant right?"
"Now imagine that the number of children dropping into the center is lower than those being flung off of the edge. In a few minutes, you have less total children in the platen right? The effort you have to exert to keep it spinning is going to be less. that is a Centrifugal pump. Less flow = less work. Restriction means less flow."
Disclaimer - the guy making that post gets all the credit for this analogy. Also, no children were harmed in the making of this public service announcement. Just a Gedanken experiment.
http://cr4.globalspec.com/thread/761...r-Current-Draw
shamelessly copying from that:
"Now for a Centrifugal pump, think of one of those push type merry-go-round play structures at the playground. Imagine 20 children loaded up on top of it, all the way out to the edges. Now imagine trying to spin it. It's going to be difficult, right? So imagine an endless flow of children dropping into the center while it is spinning, and the children on the outside edges falling off at the same rate. The work you have to do to in order to keep it spinning is constant right?"
"Now imagine that the number of children dropping into the center is lower than those being flung off of the edge. In a few minutes, you have less total children in the platen right? The effort you have to exert to keep it spinning is going to be less. that is a Centrifugal pump. Less flow = less work. Restriction means less flow."
Disclaimer - the guy making that post gets all the credit for this analogy. Also, no children were harmed in the making of this public service announcement. Just a Gedanken experiment.
05-04-17, 09:51 PM
#25
This post is not about volume of engine coolant or thermodynamics of the water pump internal casting roughness as a factor in surface area (are we past looking at the water pump as a heat exchanger? ) but surface resistance to coolant flow at operating temperature(the thermostat is open) through operating RPM range.
Never ever did I talk about the water pump as a heat exchanger.
Never ever did I talk about the water pump as a heat exchanger.
Thread
Thread Starter
Forum
Replies
Last Post