Super fast warm up mod - Engine insulation
 

So, I have a new 7 mile commute, and it is currently winter. Of course this leaves little time for the engine to warm up let alone time to operate with a warmed up engine, or get any heat out of the vents. So, I thought about my options. A block heater is a must. I do have a 1000W Kats circulating block heater. Unfortunately, I haven't had a chance to install it yet. Also, it only heats me up for the trip to work, not the trip back. I'd like something that can give me a warm engine (and heat) both ways. So, I went over some ideas we've talked about here before and what OEMs have done, a coolant tank/thermos, using exhaust to heat the coolant, grill blocking (done already), and lastly insulating the engine. I've pretty much settled on insulation due to the low cost and relative ease it should be to do this. Why would you need a thermos if the engine itself is insulated? Seems to take some complexity out of the situation.

Once it starts to warm up outside this will cause issues I'm sure with my massive grill block. At that point I'll probably have to cut some holes in it or work on some type of actuated block. Until then I was thinking fiberglass duct insulation (~R3) would do well to hold the heat in. I'll probably also extend the insulation around the transmission to help warm it faster as well. I'm not sure how warm it gets though. Perhaps I'll leave this insulation as removable for warmer weather.

Thoughts? I know a guy did this with his Insight. I'm not sure how it worked out for him though.

I've been taking data, and I'm convinced engine temp might be the single biggest factor in determining my mileage in the city. Here are a sample of my numbers from today over various trips I've taken. The first number is my engine temp as indicated by my UG at the end of the trip. The second number is my mpg from the trip. The first trip was from a cold start; the rest were warm.

152/27.9
181/31.1
190/39.1
176/29.2

Other variables that surely impacted it included my trip distances, trip mph, intake temp, and so on. I recorded those too. Engine temp seems to have the highest loading so far, however. I've been experimenting with various forms of insulation here too. The most successful to this point have been cardboard blocks around the radiator. I'll be very interested in seeing how your numbers are affected by your mods here.

A thermos is much easier to insulate than the whole engine and/or engine bay. Also, the thermos itself isn't a source of heat as the engine is, so no risk of overheating. But I totally agree about the complexity.

My primitive engine blanket only slightly slows down how fast the aluminum block cools off (engine temp 2-3°C higher after 3 hours with ambient air temp around freezing). Better insulation will give better results, but you should watch out, since your gasser will get hotter than my diesel. Maybe you should deploy the insulation only while the car is parked, and take it off for longer trips?

I don't think that my gas engine will get any hotter than your diesel. It will produce more heat, but not get hotter. The cooling system should be more than capable (without a full grill block) of disspating the heat that the engine produces. As it is now, just turning my heater fan to the 2nd setting (of 4) basically stops the engine from warming up any further on the way into work at ~32F/0C. If I turned the fan up I know I can (because I have before) cool the engine down. This all changes once summer rolls around. So, I'll have to plan something for then.

http://ecomodder.com/forum/showthrea...-em-10529.html

These keep engine heat in for the trip home, from the trip in.

They are the easiest, cheapest mod you could ever make.

The idea (since I don't run any bellypans) is to make the engine compartment like an open cardboard box, except upside down i.e. reduce the drafts that carry the heat away, and also reduce the radiated thermal losses. Of course a belly pan would make that even better, as would weather stripping and taping and really plugging up all the leaks, but I've seen good heat retention with the simple measures I've taken.

If needed they can be pulled out for summer duty... although, I don't pull them out any more. I guess I haven't worked my vehicles hard enough in the summer for it to become an issue.

How about manipulating the signal (with a parallel resistor) the Coolant Sensor sends to the ECU so that it doesn't use so much fuel during Cold Start?

Probably best to use a variable resisitor at the start so that you can find the max temp deviation you can apply before the engine misses too much during start up.

I've got mine set to about +60 deg C and its fine starting up, even with the 4psi or so lower FPR I threw on to minimise idle consumption.

:)

That would work if I actually let my car idle much. However, I use pulse and glide to the extent that idle time is pretty unimportant. I'm basically just trying to get heat plus the engine efficiency of a warm engine.

MY engine is insulated on top, compartment is closed on the bottom. Engine is still half warm at lunch time in teens weather..

You do realise that the ECU still adds extra fuel on top of its look-up chart value (from another look-up chart correction factor) during acceleartion until coolant temp hits btween 60-80 deg Celcius? Meaning that 10c resistor will literally pay itself back within the first few miles.. :thumbup:

You don't see a 7% gain in fuel consumption over a full tank worth, solely from reduced cold-start idle consumption. ;)

While I like the idea of a warm engine, (can't get mine to warm up in this weather).
I would keep the transmission cooler, especially if its an automatic.

Yeah, what I meant was that your engine produces more heat.
So until it gets hot, you need a warm hat and a good pair of gloves, so that the heater doesn't rob the engine of what heat it has.

In the summer the insulation can be lighter, since there is a smaller DeltaT.

Get that belly pan on & throw whatever insulation you have in there for a trial.

The perfect is the enemy of the good.

One thing that affects warm up time is the amount of coolant and oil that needs to be heated. So let's think about some ways of reducing the amount of coolant and oil that need to be warmed up. These would be used only during winter.
A few things that come to mind would be
- inserting objects to displaced some of the volume that would normally be coolant. For example, insert a 1.5 foot 3/4 " diameter solid plastic cylinder into the radiator, insert it in through the cap. (You can take it out in summer)
- Squeeze the radiator and heater supply rubber hoses half-way using mini-clamps
- Use a smaller oil filter (if this is possible)

The insulation ideas mentioned by other others (insulating oil sump, oil filter, Heater supply hoses) while extending time to full cool down, don't address an 8 to 9 hour cooldown where as having less coolant and oil to warm up should reduce time with enriched fuel mixture and the driver may be able to turn on the heat a few minutes sooner.

What prompted this idea is that I have a 2003 Sienna with front and rear heating which took twice the time to heat up compared to my 2008 Scion xB and then I noticed the Sienna has 11 quarts of coolant versus 6.2 quarts for the xB.

Also has anyone tried insulating the heater core supply and return hoses.

Another idea that just came to mind is teeing into the Transmission cooler tubes and feeding the warm transmission fluid through an insulated canister that will warm the radiator as soon as the transmission spins. Scratch that idea.... this is more fluid to heat.

A die-hard modder might consider a seasonal change between a "winter" radiator (smaller volume) and a "summer" one (normal).

Unfortunately, radiator size has nothing to do with warm up time. You must reduce the volume of coolant within the engine block to warm up faster.

Can anyone think of a clever way to use exhaust manifold heat (which appears very quickly after start) to help other stuff warm up?

Maybe some kind of heat exchanger? Closed loop of fancy synthetic heat-resistant oil that could handle exhaust temps. Oil/air heat exchanger in the exhaust flow (or wrapped around the exhaust pipe), connected to an oil/water heat exchanger in the coolant loop. Complicated, expensive, and probably heavy.

OTOH, small airplanes (and some cars) have heaters that pull warm air off the exhaust manifold, so you could eliminate the heater core loop (maybe 1qt. of coolant, heater core and hoses) and get nearly instant heat. Have to figure out a way to monitor for exhaust gasses in case the exhaust system starts leaking. Dash-mounted CO sensor would handle that, I think.

It would require ductwork from the manifold to the HVAC intake port, and wouldn't pull heat on recirc, but heat and recirc don't usually get used that much together anyway. An intrepid ecomodder should be able to handle a little more adversity than the typical car buyer, so maybe it would work.

I suppose it would create a theoretical increase in the length of time it takes the catalytic converter to warm up and start working, but I doubt it would be significant. Relative to heating up a cat to operating temp, warming the cabin seems like pretty small potatoes.

Heres a discussion on that topic.

http://ecomodder.com/forum/showthrea...very-7107.html

Obviously you have forgotten that the coolant thermostat, when cold doesn't actually completely stop the flow of coolant around the engine, therefore meaning a smaller radiator would actually make a difference.

:)

Even if there is some leakage, a smaller radiator is not going to speed warm up times. That tiny bit of coolant is going to be cooled weather it is a large or small radiator.

Inserting something to displace the coolant could work but it would need to be on the side of the engine block so it can heat up sooner.

I would advise against clamping the radiator hose as it could weaken the hose and burst or pop off at a later time. Insulating it might help but if you want to decrease the volume I would look for a smaller hose.

I would not go for a smaller oil filter as the difference in capacity will only be a few oz and the filter will clog sooner and open the bypass or cause the oil pump to work harder. Stay with the factory size oil filter or go larger.

One more note oil will take longer to heat and cool than the coolant so using that to heat the coolant will not work well when cold but it could help the coolant heat the oil once the car is to operating temp.

There are engine oil heat exchangers mounted at the oil filter inlet to hasten engine oil warm-up and to keep temps from spiking while underway (working hard or hard conditions). This is from a police-spec Ford, and here is a diagram from a Chevrolet.

MOPAR used to sell one that was simply a block filter adaptor with two lines for coolant ingress/egress, and ran to radiator and from the water pump. Used on early V6 minivans. Looked like this.

Is this for the prius? I insulated mine a year ago including a belly pan. It works quite well if you seal the hood properly with weather stripping. The best deal is the super thick pickup truck bed cover seal. For the bulk of the job I was very lucky and found a few sheets of 1inch engine bay sound insulation with the reflective foil on it. It just sits on top of the engine and can be removed easily for maintenance.

As for quick engine heating one possibility is running the exhaust pipe throughout the engine compartment. Not an easy task but with some bypass valves it would be simpler than heat exchangers.

One thought I had, when not near an outlet ,was powering the tank heater from the battery but I'm not sure the math works. Also, where do you get a 300 - 110 volt converter?

Could that be the effect of engine cooling? Have you noted the coolant temps at startup in the morning and afternoon?

Hmmm, I'd say its probably not a real large factor. With the block heater on the Prius, its about 90F when I start it in the morning. When I leave from work, the thermos is still pretty warm and the engine is at roughly 80F as soon as the engine kicks on.

When I started this thread, the intention was to insulate the Paseo's engine. The Prius could definitely benefit from faster warm up though.

Do you have any pictures of your insulation job?

Randall's Insight
 

Doax,

Whenever I see a thread about insulating the ICE for better performance,
Randall's Insight comes immediately to mind. The ICE is completely covered
and has imbedded temp sensors.

(Click to enlarge)
Attachment 8055

A sight to behold!

This shows what is achievable... well, at least by some... or by one. :rolleyes:

Read more about Randall's Insight.

(This has been posted before, but it's so spot-on for what you're thinking
about it deserves a fresh airing.)

my version of "winter grill cover"
 

Hi,

I tried to make some kind of grill cover for winter comutes to my job (I drive 8 miles to my work). I wanted the diesel engine to warm up a litle bit faster and save/insulate some heet during short stops.

I left one space opened, to let some air cool the turbo's intercooler.

The car is Opel Astra, 1,9 l diesel engine

PS: unfortunately I can not post the images, not enough posts :mad:

I did this a while back: http://ecomodder.com/forum/showthrea...ids-21241.html

I "feel" i have faster warmup and i "think" i get slightly better mileage... (YMMV)

[QUOTE=dogee;338943]Hi,

I tried to make some kind of grill cover for winter comutes to my job (I drive 8 miles to my work). I wanted the diesel engine to warm up a litle bit faster and save/insulate some heet during short stops.
QUOTE]

unfortunately it seems, that I have a thermostat problem, probably will have to change it...

But than I should get the engine warm even faster :)

Has anybody tried insulating the fenders? I would imagine that some expanding foam in the fenders would help retain a lot of heat.

I just got a fire blanket for my civic. Overtop of the exhaust, from the rad to the firewall. Doesn't touch the exhaust or go near any moving parts.
http://i282.photobucket.com/albums/k...G_00000037.jpg

This is only half true.

The thermostat doesn't stay closed. When the temperature of the coolant near the thermostat reaches the limit of the thermostat, it opens until coolant which is not at the limit temp touches it and cools down the wax inside. This happens usually at least once before the temperature gauge even moves.

It will happen a handful of times before the engine is "warmed up", and even more before you get to the point where the engine is /thoroughly/ warmed or temperature stable.

Every time the thermostat opens, it lets the hot coolant into the radiator. A larger radiator will allow the coolant to spread over more area, thus cooling it faster. So yes, indirectly, a larger radiator will affect warm-up times.

if its not too hard, maybe place a cardboard sheet directly over (half, or less) of the radiator to help reduce the cooling surface? Monitor temps accordingly, of course. If this is not satisfactory, switch to the engine insulation idea. or use a mixture of both.

Radiator block would help the circulating fluid heat up faster(less open faced cooling surface).
Engine "blanket" would help retain the heat for X amount of time once shut down...

Small radiator(less surface area)=less cooling efficiency, Bigger(larger suface area)=more colling efficiency.

*Its always easier to Heat something, But not as easy as keeping your engine in safe operating temps if you are unable to correct possible issue(s) immediately to prevent damage. Wind chill factors may play a part in what you can get away with safely for warmup. And what YOU are comfortable with.


Test Test Test.

Just got an idea: What about two half-sized radiators, plumbed in parallel? One would have a valve allowing it to be closed off for winter and opened for summer. Or it could be opened automatically only when the coolant gets too hot, sort of like a second loop with a hotter thermostat. It takes up the same amount of room and shouldn't add too much weight.

I'm actually pretty surprised OEM's don't do this on light trucks. The cooling system on my F250 is hugely oversized when I'm not towing, even for the 100* summers.

I guess that warmup times aren't factored into fuel economy ratings (also, a lot of light truck are exempt from having to obtain ratings), so there really is no "value" added as far as the factory is concerned -- just an additional component to fail with huge associated risks.

Eh, also a block heater could be used to accomplish similar goals (although not as convenient as a self-contained system like the radiators) with much less risk and significantly less investment.

Anyway -- I do really like the parallel radiator concept. How about a secondary thermostat to allow flow to the auxiliary radiator?

Both of those will help once the thermostat is open. Until then, not so much. Faster warmup would really help me, since most of my trips are under 10 miles and my car takes about 10 miles to reach full temperature in winter. (with complete grille block)

+1 on the block heater. Everything else compared seems like a HUGE effort for a similar gain. though, radiators are fairly cheap and simple to acquire and plumb, from parts lots.

I guess the block heater maybe the best option since you have played with lifepo4 batteries, maybe you have a few to make a pack to run an inverter to power the block heater?

Not sure how much the heater benefits since its my understanding or misunderstanding the prius pumps its coolant into a giant thermos under the fender at shut down to repump to aid in warm up at next use. :eek:

Think Ive seen online where some guys installed a heater in the thermos?

If you plug in kit has the wiring according to Enginer I know it wont work til the Ready light appears and anything spent to ready the system faster should pay you back quickly allowing use of the phev kit too on such short trips.

I'm thinking you meant something else here, because this statement is patently incorrect.

The larger surface area of the radiator distributes heat further, causing each unit area of the cooling or active surface of the radiator to be closer to the temperature of the air flowing through it.

Greatest efficiency is achieved at a higher differential, ergo a smaller radiator distributing the same BTU would be "more efficient".

No it was correct originally there is a reason a radiator to a v8 is bigger than a radiator to a I4. They need more of a cooling factor which means more cooling fluid whether you use water or coolant. So if you put a smaller radiator on the motor than what there should be it will heat up quicker but may overheat. This can be effective on motors where the vehicle comes with both I4 and v6's and bigger as they tend not to put in a smaller radiator for a smaller motor it is easier just to keep the same parts in them.