Keeping Engine Coolant Hot
 

I read somewhere a while back that the Prius or Insight uses a special canister that stores the engine coolant after the car shuts down. It keeps the coolant super-insulated so that it stays hot longer, even overnight.

I'm wondering if there's a $5 mod that would make much difference -- installing ducting insulation wrap around the coolant reservoir.

It might not keep the coolant hot overnight, but it would keep it hotter if you leave the car for 2-3 hours.

Question about this is, would that also make the coolant hotter while running?

I looked into replicating Toyota's design over this past winter. Its a fairly complex setup with sensors and an automated valve and pump that controls flow to the thermos. Their setup is really ideal, and also not easy to replicate. Its also really the only way that is worth while IMO.

Insulating a coolant reservoire in most cases is going to do nothing. Reservoires are usually outside of the normal coolant loop so they never heat up (there are exceptions of course). In that case, insulating the reservoire still will not really not help much. If the reservoire is after the radiator then the coolant in the reservoire is already going to be cooled down. If its before (and I'd tend to think this isn't the case just due to plastics and their vulnerability to heat) the radiator then you may see a small benefit, but still not much. This is because when the engine warms up the thermostat is closed and the coolant circulates only inside the engine block and head until it is up to temperature. At this point the thermostat opens and lets cool coolant into the engine to cool it down. If the tank was insulated it would simply flow the warm coolant through until it got cool coolant again.

I have a possible solution that may only work during the day.

I have used ambient temperature plates in my refrigerated keg setup for some time now. Basically they are plates that when powered will either maintain a 20 degree cooler air temp or 20 degree hotter air temp depending on which way its switched. I would suggest gutting a couple of those coolers and attaching those plates to the sides of your radiator and powering it with solar panels, unless you want it to draw power from your battery all the time.

Just an idea to spark further investigation ...

I can see it now... hood/roof mounted passive solar coolant heaters...

http://www.builditsolar.com/Projects...g/PipeCoil.jpg

Why not!?
 

It'd be a good use for those fancy clear hoods all those tweaker rice burner drivers install.

Hi,

This is something that all car makers should be doing. Quicker warm up is a good thing!

You could maybe do a custom metal tube lines in place of the radiator hoses (I used to have pics of a setup on a straight-6 67 C10 that had this) with rubber joints for the bends and where it connected to the radiator and engine. Then grab some exhaust wrap and wrap the inlets and outlets from the radiator and engine... Possibly wrap the side tanks on the radiator too. All the cooling action happens in the fins so it shouldn't effect cooling. Maybe have a display reading trans temp since it's cooler is typically inside the radiator tanks on a typical car.

Not sure if that's totally what your looking for, but that's about as much as I'd want to insulate the cooling system on the car.

The reservoir's main goal is to collect coolant that flows out as the engine heats up (typically in an over heating situation) and the coolant expands in volume. Older cars used to just dump it on the ground via a rubber line that ran down under the car.


::edit::
Two examples of metal ratiator lines:
http://i42.photobucket.com/albums/e3...5/DSC01030.jpg
Straight metal pipes


http://i42.photobucket.com/albums/e3...6024Custom.jpg
Universal metal bendy hoses

There is a seperate thermos type resivoir on the prius, and when the car is shut off they pump it full of hot coolant. So when the car is restarted they put the hot coolant back in to the main system and "preheat" the engine a bit without wasting hardly any energy to do so.

I see what you mean.. Maybe use a 2nd reserve tank (junk yard hunt) with a small electric pump that can pull a gallon or so of coolant out of the system, and have it heated by a small electric coil. Start the engine, reverse the pump, and back into the system it goes. Though it would have to be manually controlled.

This is not a worthwhile mod guys, just slap on a oil pan heater (use block heater too) and plug your car in 30min-1hour before you are going to use it.