Electric water pump

[Gregte]

Just wondering if the belt driven water pump is ever replaced with an electric water pump?

It would seem that the only time the water pump needs to actually pump coolant would be when the engine's thermostat opens. This happens only periodically and not real frequently in cooler weather. The belt driven pump is doing work all the time whereas an electric pump would only need to do work when needed.

Or maybe the belt driven pump is doing very little work when the t-stat is not open and thus no coolant is flowing.

[Daox]

The pump really needs to be going nearly all the time to eliminate any hot spots that develop.

[dremd]

Well; you could run a controller on an electric water pump; and get away with running it much slower most of the time. Payback time? Maybe.

[Duffman]

The advantage of an electric pump would be that the pump doesnt drag more at higher RPM and can be held in the sweet spot constantly.

[Gregte]

Another thing that I had forgot about... the pump needs to be running continuously whenever you are using the heater.

Thanks to all for the input.

[Tango Charlie]

I think most thermostats have a small hole in them so they still circulate a small amount of coolant when closed. At least the thermostats that I've seen.

[MazdaMatt]

I had some overheating problems last weekend (tstat crapped out) and my friend/mechanic explained the cooling system to me. There is apparently a bypass for the rad so the water pump is always circulating coolant within the engine. When the coolant gets too hot, the tstat opens and it starts also coursing through the rad to cool it. You can't run without any water going through or your head would probably warp.

I know that racers use electric water pumps because they push the crap out of their engines, then have to turn them off while blistering hot. They run the water pump for a while with the car off to make sure it cools evenly and doesn't warp anything.

[larryrose11]

Hey guys,
First of all, I wouldn't undertake something like this if you are not comfortable programming a micro computer of some sort, like an Motorola HC11.
Your effots could be put in a better place, like switching over to a manual rack and pinion steering, or plug in battery w/ alternator field kill switch.

I know a bit about electric water pumps. They make sense, mostly on the HEV's I work on for my job. They can run at optimum speeds, instead of just engine speed. Typically coolant pumps on gasoline ICEs actually rely on cavation to limit pump flow!! in order to control e-pumps well, you need to know where you water temp sensor is, and the transfer function for the sensor. You set some minimum flow, say about 0.1 gpm. This will help the engine warm up much faster. There needs to be a target engine coolant temp, say 190F, but below the threshold for radiator fan operation. Use these as your bounds and tune a PID to run a small brushed motor controller that has a 0-5V input.

So here is the non-propriety data: The real benefit to using a E-pump is the elimination of the belt all together. Most modern HEV's already have e-power steering and e-Air Cond. In an HEV, the alternator is redundant, and not present, that leaves the water pump on the belt. The belt, all by itself uses 2-3 HP with no load on it, but that load is pretty constant and doesn't change. Switching to an e-pump allows you to shed that load.

[ATaylorRacing]

To gain more power out of the first car I drag raced I made a electric water pump set up. The car was a 81 Horizon and I bought an electric water pump called a "Water Guppy" that was used to circulate water in bass fishing boats. I had the water pump off of my car (due to bad leaks) and found that the thermostat housing had two bolts that lined up with two where the pump was. I simply bolted on an extra thermostat housing in place of the pump and then put the electric one in line with some longer radiator hose. I ran the pump with a simple on off switch in the car and in hot weather it worked like a dream. I never checked for gas mileage. A trick that a lot of drag racers use is to cut off every other fin inside the water pump. They have less drag, more power, more miles per gallon, and adequate cooling.

[ATaylorRacing]

Originally Posted by Tango Charlie

I think most thermostats have a small hole in them so they still circulate a small amount of coolant when closed. At least the thermostats that I've seen.

Most of the older cars did not have that feature. I know that the first one I saw was on my 94 Plymouth Sundance Duster....reason for it was to not have as many head gasket failures due to the big temp differences of the water coming in when the thermostat opened up. Since 81 I used to always drill a couple or three 1/8" holes in mine.

[MetroMPG]

Originally Posted by larryrose11

I know a bit about electric water pumps...

That was some good info, thanks.

[CobraBall]

Electrical water pumps are common in auto racing.
<http://www.jegs.com/webapp/wcs/stores/servlet/category_10001_10002_10135_-1_10131>

They can be controlled electronically to adjust the rate of coolant flow "even after engine shut down".

Plan on purchasing an extra motor. You can get a engine driven mechanical water pump just about anywhere. Try to find the replacement water pump electric motor at your local Auto Zone.

I considered putting an electrical water pump on my '33 Ford but gave up the idea. Most electrical water pump mgfs. say they pumps are for racing only.

Simple is usually more reliable.

[CobraBall]

Excellent discussion for an Electric Water Pump installation.

EWP Installation

[NiHaoMike]

At the same time, a heating element in a pipe can be installed inline with the bypass and a simple control circuit used to make a crankcase heater.

[95badbird]

electric water pumps.

they work great on daily drivers.

they also work great on race cars.

I run one on my 95 bird....the beauty of it for me, is I can cool the car off(going from 190 degrees to 170 degress in minutes) in the staging lanes before the next race, with the engine off!

parasistic drag from any accessory hurts any kind of mileage or power.
depending on the vehicle make, some e-water pumps come with an idler pulley built in, so belt routing stays the same.

[bikin' Ed]

Ok, I like not having the drag on the belt driven waterpump on my engine. Since the E-pump will have to runn all of the time, how much more drag will be placed on the engine due to the alternator supplying power for the extra electrical load?

Since there are probably soooo many variables, let's limit replies to hypermiling road vehicles with a small V-6 or less ICE. Thanks

[95badbird]

the one pictured above, only has a 7 amp draw.

http://store.summitracing.com/partde...5&autoview=sku

[NiHaoMike]

Hey guys,
First of all, I wouldn't undertake something like this if you are not comfortable programming a micro computer of some sort, like an Motorola HC11.
Your effots could be put in a better place, like switching over to a manual rack and pinion steering, or plug in battery w/ alternator field kill switch.

Isn't the PWM control just a matter of using a MOSFET controlled by a common PWM chip? For temperature feedback, just mount a sensor on a pipe and use it to increase the duty cycle of the MOSFET. And maybe also add a PWM circuit for the radiator fan as well, and perhaps a servo motor for opening and closing the vents.

BTW, a friend of mine showed me a "desktop supercomputer" she designed the cooling system for. It was complex enough that the cooling system, consisting of a 2HP BLDC scroll compressor, R-410a refrigerant, a large condenser, 9 PZEVs (8 for the main CPUs, one for compressor cooling), and 8 evaporators, had a 200MHz CPU just to run it! Of course, that was because the CPUs had to be kept below -40C to operate correctly. An automobile engine is nowhere near as sensitive to temperature variations as a high performance CPU.