My Engine Heater

[bob865]

Hey Guys,

I just tested my new engine pre-heater this morning and wanted to share.  I don't have the luxury of a hangar or electricity so I couldn't use the "normal" engine heating methods.  Luckily, here in South Carolina the need to pre-heat an engine doesn't happen all that much.  But when it does, I didn't have access to a good solution.  So I built my own.  My requirements where it had to be self-contained and able to function without having to be attached to any other service, lightweight, and small enough to fit int he baggage compartment in case I wanted/needed to take it with me.  This ruled out every option I was able to find.  What I ended up building was a diesel/electric powered heater.  The heater is a 5000 watt diesel heater that is typically used in cold climates to preheat cars or to keep trucks/campers warm without running the engine.  I mounted this in a toolbox with a small motorcycle battery for power and a small 1 Liter fuel tank for scooters.  There is an intake on one side which I will add a filter to later and an output on the other with a flexible duct I can put into the cowling.  The control is on the outside so there is no need to open the box except to charge the battery or add fuel.  The heater is flexible fuel wise so, in a pinch, it would also run on jet fuel or kerosene.   Maybe some of you snowbirds on mooneyspace can offer some feedback on ways to make it better.

--Adam

 

[warren.huisman]

I like it.  How much do you have invested in it?

[bob865]

1 minute ago, warren.huisman said:

I like it.  How much do you have invested in it?

Around $375 give or take some for hardware and miscellaneous parts. 

[MIm20c]

Very nice!  If I had a hanger without electricity I’d permanently store a generator and use a couple space heaters. But at a tie down that’s a great way to avoid hauling around a propane tank. 

[larryb]

That’s really cool. What is the source for the heater unit?

[takair]

Have not seen that type of heater before.  Nice concept.  Does the inside of the tool box remain cool?

[carusoam]

Hey Adam, that looks pretty interesting.

At an outdoor tie down for a decade, I had a couple of propane experiments I tried...

Some things I learned...

1) To Get the engine started doesn't Take heating the whole engine...  

2) The intake tubes and fuel lines are the most important... don't overheat the fuel lines into vapor lock territory...

3) for Best lubrication, heating the oil sump is important...

4) Around $500 for Red dragon propane system... and it still needs a battery and a propane tank....

5) NJ gets a lot of days around 20°F.  below that a bigger heater may be necessary...

6) got enough time... warm engine, oil, intake, battery, and cabin....  

7) my Airport has a big heater.  The line for it can get really long on a cold weekend morning.

Best regards,

-a-

[kpaul]

@bob865 is that considered a "parking heater"?

If it is I would assume the case stays fairly cool since it is intended to be mounted in a automobile engine compartment. 

How long does it run on 1ltr of fuel?

have you figured out the temperature that it exhausts?

And the always important Mooney question...what does the finished kit weigh?

[bob865]

10 hours ago, larryb said:

What is the source for the heater unit?

For my Proof of concept, I got a Chinese one off ebay.

 

6 hours ago, carusoam said:

4) Around $500 for Red dragon propane system... and it still needs a battery and a propane tank....

That's what made me start working on this in the first place.  That was the closest I could find to what I needed but was over $500, not light and not portable.  Good for an FBO, not for an individual.

29 minutes ago, kpaul said:

@bob865 is that considered a "parking heater"?

Yes it is.  This one is a Chinese clone of a Parker I think was the name.  And yes, the inside of the toolbox stays ambient outdoor temperature.  The intake and exhaust for the actual combustion have ports on the back of the toolbox.

30 minutes ago, kpaul said:

How long does it run on 1ltr of fuel?

have you figured out the temperature that it exhausts?

And the always important Mooney question...what does the finished kit weigh?

Based on what I saw yesterday, I should be able to get well over an hour on 1 liter. The temp of the output is hot enough you can't keep your hands in the stream long, but temp wise, I'm not sure.  And for the weight, I'll put it on my scale tonight when I get home, but less than 30lbs I'm guessing/estimating now.  I wanted it small enough to fit in the plane.  I visit my parents in GA and the airport there is a really small country airport with no support equipment.  Need to be able to take it with me.  Exact numbers I hope to prove out and be able to answer soon, i.e. runtime on battery, fuel burn, weight, output temp, etc.  Any other details that would be good to know?

 

[TonyK]

Very cool (hot) idea.  I have a few suggestions.

1.  Get some Explosafe foam or stainless filling for the fuel tank.

2.  Look at the fuel bottles used for hiking.  They can take the pressure of the fuel during transport.

3.  Insulate and sleeve the duct.

4.  Move the control unit into one of the covered areas in the lid of the toolbox.

I'm very interested in what kind of run time you get out of it.

[N201MKTurbo]

What is the battery endurance?

it is very cool!

[EricJ]

Awesome.    You should look into selling those!

 

[takair]

Is that a small pump mounted in there?  Also, what is the line that goes out the back?  This really is a good idea.  I’m on something like V10 of propane powered units, and while they work, yours looks more elegant and easier to operate safely.

One thing people would ultimately want to know, if you were selling this is BTU output, or more importantly, time to heat the engine under various conditions.  For example, if it is 10F outside, how long to get the engine oil to....let’s say....30?  Not really sure that there is a standard, I typically use the freezing point as my trigger to preheat.  Maybe see what some of the commercial heaters use as a standard.

[bob865]

14 hours ago, takair said:

Is that a small pump mounted in there?  Also, what is the line that goes out the back?

Yes, that is the fuel pump for the heater and the line going out the back is  the fuel line.  The fuel inlet is on the back of the toolbox.  The only part I don't like about my design.  But I'm going to build a metal shield/guard that will cover the fuel inlet and fuel line and also help guard against something touching the hot exhaust port.

The BTU conversion would be 17,050 BTU.  Quick note, 30,000-45,000 BTU is enough to heat a 2 car garage.

[bob865]

Finally have some more details:

• The box dimensions are 12"x22"x12". 
• She weighs 24 pounds fully loaded
• a full tank of fuel and fully charged battery will run an hour
• Output temperature is 200 degrees (with a 55 degree ambient temperature)

The one hour cutoff is when the internal battery hits 11.6v which is critical voltage for lead acid batteries; there is still fuel left at this point, but less than 25% remaining.  It will run longer, but it's not a good idea to avoid damaging the battery.  The built in battery is necessary, at least for startup because of the current draw when the glow plug is on during the startup.  It could be setup to use an external source (i.e. plugin to a cigarette lighter) as a supplementary power source to get more run time if needed.  Now that I see the available space, the battery capacity could be increased or even the type changed to increase run time.  When starting there is a 1.5 minutes purge cycle and it will light off and starts producing heat by 3 minutes.  There is also a 6 minute shutdown/cool off cycle.

[thinwing]

Great idea...I would change the lead acid for 1 0r 2 5000 mah 3 cell lipos...nominal voltage 12.3 v and much lighter than leadacid

[Yetti]

Metal tool box would contain things better if things went south.  

I ran a small led bar light for 2 hours (still going, just had to go to bed) off one of these  https://www.amazon.com/Fireproof-6800mAh-Rechargeable-Protable-DC12680/dp/B074TCD7NF/ref=sr_1_6?s=electronics&ie=UTF8&qid=1518365413&sr=1-6&keywords=super+rechargeable+liion+battery

Buy some tie wraps and clean up the wiring

 

 

 

[bob865]

On 2/10/2018 at 11:12 PM, thinwing said:

I would change the lead acid for 1 0r 2 5000 mah 3 cell lipos...nominal voltage 12.3 v and much lighter than leadacid

I thought about lipo, especially since I have some 3s packs laying around for my rc planes, but went with the lead acid for stability.  I was concerned about fire, but I see @Yetti has posted a fireproof version.  I'll have to look into those.

19 hours ago, Yetti said:

Buy some tie wraps and clean up the wiring

The next version/mod will be to re-pin all the connectors to get the wiring more reasonable lengths.  Right now it's a mess because there is so much extra.  The harness has enough wire to mount the thing in the back of a car/truck and still connect to the battery in the front.

[Yetti]

I would not trust the Chinese claim of putting it in a plastic case to make it "fireproof".    I saw nothing fireproof about it, but did not open it up.   My understanding is the circuitry for charging and discharging is what makes a LiPro "fire resistant"

And if you are going to carry it in the plane SLA may be much much better now that I think about it.

[DonMuncy]

I like this heater.

I have a plug-in heater in my hangar, and seldom fly overnight in cold weather, so the need for a portable one is not very high on my priority list. Plus I live in Texas.

I think if I was an FBO owner someplace a little further north, I might consider having a few of these on hand to rent for transient folks. 

[Yetti]

is it better to heat the area around the engine or stick the heater up the exhaust pipe and heat the internals of the engine.... and possibly the cabin too?

[jaylw314]

39 minutes ago, Yetti said:

is it better to heat the area around the engine or stick the heater up the exhaust pipe and heat the internals of the engine.... and possibly the cabin too?

Heating from outside in is probably better.  Less chance for condensation in the engine.

Besides, running hot air into the exhaust will just heat the exhaust pipes, since it won't make it into the engine.

Also, I'm not clear on how the heater works--does it actually burn the diesel and use the exhaust gas, or does it convert it into electricity and then heat an electric element?  If it's the former, I'd worry about humidity in the exhaust gas condensing on cold metal parts...

[larryb]

I read the manual for the parking heater. Combustion gas is totally separate. There is a separate air intake and exhaust for the burner side. There is a heat exchanger. Just like a house furnace.

 

[jaylw314]

5 minutes ago, larryb said:

I read the manual for the parking heater. Combustion gas is totally separate. There is a separate air intake and exhaust for the burner side. There is a heat exchanger. Just like a house furnace.

 

Thanks!

[DonMuncy]

1 hour ago, Yetti said:

is it better to heat the area around the engine or stick the heater up the exhaust pipe and heat the internals of the engine.... and possibly the cabin too?

I fitted my plug-in heater with a 4 inch semi-flexible (think clothes dryer) hose. I stick it up into the cowl flap and crack the oil filler door on top to allow some movement of air.