Fast warm up ideas: Oil to coolant heat exchanger

[Varn]

I used to be chairman of a municipal electric utility.

We always ran electric heaters in the oil tanks for Fairbanks OP 12 cylinder 24 piston turbo/supercharged 2 stroke diesel motors. The tanks held 250 gallons of oil. It allowed the motors to come up to full power in 20 minutes vs a 2 hour warm up time with cold oil.

[Enki]

A lot of current (and even slightly older) Mazda and Ford passenger cars use an oil/coolant heat exchanger which both cools the oil when it's up to temp as well as heating it up faster when it isn't. Attached is what the basic assembly looks like (black part is the exchanger, green is the oil pressure sensor) as well as a quick and dirty cooling system map for my car (2009 Mazdaspeed 3).

The cooling system map may not make much sense but the basic gist of it is that the coolant comes out of the head, goes into the heater core (which has its own internal bypass), comes back out and goes into the oil cooler, which then dumps back into the thermostat housing where the flow cycle starts all over again. These cars use a constant mix of radiator coolant as well as engine block coolant but never draw 100% from the radiator (which is pretty small as it is).

Hope this helps you find more options.

[ThermionicScott]

"Spinny thing with wooshy noises", lol.

[Enki]

Yeah, the turbo. I wasn't exactly in my right mind when I drew that thing up.

[sbestca]

Originally Posted by oil pan 4

Those are pretty much never found on domestic cars.

Actually they are, on many police cars, turbo cars and HD trailer towing options. My 92 Crown Vic police had one, as did my 84 and 86 Mustang SVO, 87 Thunderbird TurboCoupe, and my 94 Thunderbird Supercoupe (and my 86 Ford E350 diesel van, but a different design).

Hmmm, it's under there somewhere:

[toc]

The obvious is that the jacket (you know, the bit around the cylinders that coolant flows past to cool the oil and cylinders) is already a heat exchanger.

Insulate the oil pan which will reduce temperature loss via the momentum of the vehicle moving (or just to the ambient low 'merica conditions).

The jacket isn't as efficient as the plate heat exchanger in the OP, but that will also function to cool the oil (essentially bringing both mediums to the same temperature, and if left in would heat the coolant up, thus forcing cooling to be required too - i.e. your oil will also only reach up to whatever your cooling system is over engineered to cool to).

[Tulok]

I agree with insulating the oil pan being the first step. If your car is FWD and the exhaust runs underneath the oil pan, you can rig up something to block that exhaust heat from being whisked away so easily as well.

I think the exhaust heat is going to be the fastest way to get the oil temps up. Even manufacturers are looking into utilizing wasted exhaust heat these days.

[oil pan 4]

I was actually going to get a smaller more compact heat exchanger.
Then I found a flow and pressure drop chart.
Turns out a 10 plate 3x8 inch HX is only good for about 5 or 6 GPM, perfect for a small 4 cylinder engine and probably most V6 engines.
20 plates is good for 10 to 12gpm, that could work for around 90% of all non towing applications.
The 30 plate like I have is good for up to 15 to 18 gpm. The max flow on small block Chevy and big block Chevy engines is between 20 and 25 gpm.
So the 30 plate should be able to handle all the oil flow about 99.99% of engine run time.
If the oil cooler can't handle the flow the oil cooler adaptor bolted on to emgine block has a pressure differential by pass built in so some of the oil just won't go through the cooler.
If I didn't have a cooler and was going to buy new I would get the 20 plate on account of it being cheaper, lighter and smaller.

Based on the size of my 30 plate HX versus pretty much all the oil coolers I have seen I don't think they exchange that much heat.
The plate surface area of this cooler is probably about 6 to 8 times more than what I have seen on 4 cylinder engines. Sure the oil doesn't over heat, but it also doesn't warm up that fast either.
This 30 plate cooler is at least double the size of what is stock on my diesel engine.
The only time I have seen a cooler about this size was on old Detroit diesel 6-71 engines.
I usually over do stuff, this is no exception.

My operating envelope in new Mexico is from -16°F to 0°F in winter, that is what I, my self have personally seen so it may get even colder than that. In summer up to 104°F here and 111°F a little south of here.

[t vago]

My Dodge Magnum has one of these oil "cooler" things. It apparently does not have a bypass thermostat, either, at least as far as I can tell from examining the pictures of one. Also, the factory service manual only says this:

Engine oil travels from the oil cooler and into the oil filter. Engine oil then exits the filter into the main gallery. Engine coolant flows into the cooler from the heater return tube and exits into the water inlet tube.

I might have to get another one from eBay or somewhere to examine, and to possibly install in one of my other vehicles.

[oil pan 4]

The bypass is usually machined in the oil filter housing.