Fast warm up ideas: 3500w engine warmer

[mikeyjd]

Good thread.

[oil pan 4]

The new one I am working on:
5500w 18,000BTU/Hr
Has to go in a 1.5 inch pipe.
Need to find a 1.5 out side diameter to 1 or 3/4 inch bushing and a double female coupler in the same size. Just some time before it get cold again.


I may wire in a control circuit using the existing cold start switch to cycle the pump and heating element on and off. I should only need that if it works faster than expected.

[paulgato]

That looks excellent Mr OIl Pan.

The more you use the less you lose, when it comes to heating an engine. In theory at least. I personally would be nervous of using a 5kw heater though, in case something went wrong, ran dry, or the pump failed.

I don't know what temperatures you have to deal with where you are. Around here in Oxford winter temps are pretty mild, but the 1800w engine preheater I installed a couple of years ago is working well and is saving a good amount of fuel. Actually I use it all year round, and have a remote key fob thing so I can switch it on an hour before I drive off. (Of course a simple switch on a socket inside the house would work just as well, but I like being able to switch on the engine heater while still lying in bed - he he.)

One thing I found though is in the winter there's no real point trying to use the engine preheater to heat the cabin and to clear ice or condensation from the windscreens via the car's normal cabin heater. The cabin heater drags way too much heat out of the engine, and anyway the cabin heater is not really very efficient until the engine is nearly at full temperature.

Instead what I've done is install a normal household mains power socket on a short lead under the dash, in the passenger foot well. I modified an ordinary household fan heater, so rather than having a 2kw setting and 1kw setting it now has a 1kw setting and a 500w setting. (2kw together with the 2kw engine preheater would overload the outdoor power circuit, which has a 3kw limit. That's 13A, and 230 volts in Europe of course.)

That mains socket in the car is live when the engine preheater is live, so both heaters are controlled with the remote key fob thing. (The on-board battery chargers are powered up all night of course (alternator delete) but although they are quite powerful (600w max?) by morning they are down to a trickle charge so any risk of overloading the circuit is very minimal.)

I've found it much better to heat the cabin separately like that, as the cabin then starts to warm up from the initial switch-on time, an hour before drive-time, and that gives plenty of time to warm the cabin and melt any ice on the screens all around, and the engine warm up time is not prolonged in the process.

In fact, if a winter morning would normally involve sitting on the driveway with the engine running just to clear the screens so you can see where you're going, then simply having a 500w or 1000w fan heater sat in the passenger footwell should enable you to drive off straight away with full visibility, even if the engine is stone cold. It's such a simple and cheap thing to do, and very effective.

I would really recommend NOT relying on the engine preheater to give enough heat to clear the screens, when that can be achieved so easily and directly with a household fan heater. In fact, as long as the screens are clear, the engine only really needs to be up at about 50 degrees Celsius to avoid the really bad fuel economy on a cold morning. That's my feeling anyway, just from watching the in-dash real-time mpg meter with a stone cold (0 degree C) engine vs a 50 degree C engine vs a fully warmed (92 degree C) engine.

The really bad mpg hit occurs below 50 degrees C engine temp, but a 50 degree C engine is pretty useless at clearing ice from screens and heating the cabin, because the temp gradient across the coolant/air heat exchanger in the car's cabin heater is insufficiently steep for significant heat transfer until the coolant is up at around 85 degrees C or more.

...

Oh, and by the way, I don't point the household fan heater at the windscreens. I've heard of people cracking windscreens that way in extreme cold, but also it's not necessary or efficient. I sit the fan heater as far forward as possible in the passenger footwell and have it blowing hot air towards the passenger's feet, as it were. With 500w or 1000w there's no danger of overheating any upholstery materials if you have a half meter or so clear space in front of the heater, and the heater has a built-in thermostat of course. That works, and over a half hour or an hour warms the whole cabin evenly. It's satisfying to look out on a winter morning and see frost/ice/snow covering all my neighbours' cars, and none at all on mine. I see them wrapped up in coats and gloves, laboriously scraping ice off windscreens while their engines chug away, belching steamy exhaust fumes into the street, and I just saunter out with my coat under my arm, get in and drive away.

[oil pan 4]

Hot water heater elements are designed to fail safely if they are over heated or ran dry.

The electric pump I use the primary engine coolant pump, not an add on. They have proved very reliable.

I originally lived on the east coast in Virginia, which had a climate kind of like what I have seen in southern England. (I had not have the pleasure of experiencing a winter in London). Other than that, I did like the weather aside from the copious amounts of rain.
Living on the eastern coast I didn't even think that this part of the country had a winter.
The winters in the high plains of New Mexico have been unbelievably harsh.

In this part of the country nights that get down to -10'C or lower are perfectly normal.

Preheating the car I was going to use a 2 fold approach.
In the U.S. small light duty low wattage items to include most appliances, tools and small space heaters use 120 volt power.
High power items like electric clothes dryers, electric hot water heaters, larger air compressors use 240 volt power.

The feeder plug I am going to use to supply power can handle 30 amps of 240 volt power and supplies both 120 and 240 volt power.
I will use hot water heater element for mostly just heating the engine and the space heater for inside the vehicle.
I have been using the space heater buy its self melt ice off the out side of the car and it works ok.
The hot water heater element is added in line with the heater core. So I can run the blower fan and get a little bit more heat, if needed.
In my 2008 test I used a 2400 watt coolant heater by its self and it was able to start melting away frost on mornings that were just below freezing in about a minute or two in this configuration.

[paulgato]

Oh, so your winters there sound about the same as ours in England. It doesn't tend to get below -10C very often here.

Your experience is interesting. My 1800w coolant heater is also pumping warm coolant directly towards the heater matrix, but I found use of the car's cabin blower not very useful, and yet using it seriously slowed down engine warm-up.

The difference I guess is that my car's engine coolant pump is driven off the cam belt rather than being electrically powered. The coolant pre-heater's pump is quite small and weak in comparison. Yes, I can see that if you are using the main engine coolant pump then that can easily cope with a 5kw heater. A 240v electric shower, after all, will use 8kw and upwards. The coolant pre-heater I installed comes in a '3kw' or a '2kw' version. I went for the 2kw version so as to be able to run a battery charger and a fan heater off the same standard 13A RCD-protected outdoor power socket.

My feeling is that in the absence of a powerful coolant pump such as yours, I'd be inclined to distribute the heating power, so for example I could add a modestly-rated thermostat-free pad heater to the oil sump pan, and possibly a similar pad heater to the gearbox housing.

The pre-heated circulating coolant is maintained thermostatically at between 75 and 85 degrees C (10 degree C hysteresis) but as soon as the engine is turned over that coolant temperature drops immediately by between 10 and 15 degrees C. One reason for that will be cooling via the oil/coolant heat exchanger (AKA 'oil cooler') but also my secondary pump will probably not pump heated coolant around all parts of the engine as the primary engine coolant pump does with the engine running. Not much I can do about those unheated coolant pathways, but I can safely heat the 5 litres of oil in the sump to 150 degrees C without risk of degradation. The pan is aluminium so will spread any heat quite efficiently and not create a hot spot in one location.

The difficulty is that then I'd need a 2nd 13A outdoor circuit, and that's not entirely practical in this house, for reasons I won't bore you with. I guess I might be able to run a 300w pad heater without issue on the same circuit, but I'd rather not even do that. One possibility is to use the coolant preheater's thermostat to switch the oil pan pad heater and gearbox heater on whenever the coolant heater element switches off.

But it looks like you need a plumber there. Those fittings look like standard water or gas pipework fittings, and all those bushes you need will be easily available I would imagine in the plumbing world. At least they would be in the UK.

[oil pan 4]

I am going to try to power everything off a 40 amp 240 volt circuit. It will have a neutral wire for powering 120 volt stuff too.

The pipe thread parts are real common here too, I can get the plumbing bits from various internet stores.

[oil pan 4]

The 3500 watt heater has been succeeded by the 5500 watt frost thwarter.
http://ecomodder.com/forum/showthrea...9-a-32503.html
And its working pretty good.