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The current problem with block heaters is that they require another power source. You have to find a wall outlet somewhere and plug it in using an extension cord. What I propose is an improvement in 2 ways.
First, there's an extra battery which is not used for anything other than the block heater.
For diesel engines which require 2 block heaters, one on either side, there are 2 extra batteries, one for each heater. These power the heaters when you have to use them, so you don't have to find a damn outlet. Also, a temperature sensor is included that automatically turns on the block heaters if the engine becomes too cold to start, so you don't wake up, realize it's too cold, then have to wait 5 hours for the block to warm up. You can disable the automatic part with a switch in the cab if you plan on leaving the vehicle off for more than a single night. This would've come in handy in Montana earlier this week when both my crew's vehicles refused to start after a night when it dropped to -34 Farenheit. That sucked, ok? So I think this could prevent such disasters.
By the way, I don't recommend a trip to Great Falls, Montana to anybody, ever. Those people are just plain mean.
200 Watt Engine Block Heater (120-Volt)
http://www.jcwhitne...UppECFUaPOAoddk41ew
Magnets hold it to the oil pan. [Amos Kito, Feb 02 2008]
How Long Does A 12-Volt Battery Last
http://www.physicsf...thread.php?t=160033
This example is about powering a 150-watt device. [Amos Kito, Feb 02 2008]
[link]
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First question: what is the power
consumption (wattage) of regular block
heaters, and how long do they need to run
for in order to warm up the block by the
necessary amount? |
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In fact, let me take a guess. Suppose
you're trying to warm up 100kg (?) of
iron by 10°C (?) |
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The specific heat of iron is about 0.5 J/
g/K, so this is going to require about
0.5MJ of energy. This assumes that
there are no losses (ie, the block
doesn't lose much of the heat you're
putting in). |
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Lead acid batteries store about 0.1MJ
per kg, so you're looking at a 5kg
battery in order to warm up your block
once. |
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Clearly, then, this is likely to be
feasible. However, I wouldn't leave the
system on overnight. |
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Incidentally, everything is a lot easier in
Centigrade than Fahrenheit. |
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The fuel you're running your engine on packs much more btu's/lb.
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So what you need is a line from your tank that runs to a small header tank holding enough for a couple heatings, a small battery to heat that up(for diesels), then light that up to heat the block. |
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(originally I was gonna say just use a can of Sterno, but this is more elegant and you don't have to get up at 3am into 4 foot snowdrifts and there isn't even any bloody coffee made and do they give you a couple extra hours on the other end? bloody army... but I digress...) |
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See [Links] for an estimate of battery drain. A 150-watt device would last "4 hours", but that block heater is 200 watts. You’ll have to fully charge the battery from essentially dead, every day. And you’ll have to monitor it while the heater's going, to be sure it doesn’t go dead too soon. I've successfully used a 100-watt light bulb (120-Volt), with a blanket over the hood, but it wasn't –34°F outside. With careful placement, and decent insulation, you may get by with a less power-hungry heater. Does it need to be at full power all night? If it were on a timer, it could run during the last 4 hours of the night. |
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sounds like you need to service your trucks, if the glow plugs were in good condition you should have been able to get them running. |
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I liked Great Falls when I passed through. It wasn't winter, though. |
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The thing that struck me most was the lack of stop signs. I don't know if that's changed. |
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So engines pump coolant around. Why not heat the coolant and pump that around. A simple propane tank and a burner to heat the coolant and just have it hooked to a timer. An hour or so before you need your truck the burner lights off the coolant pump turns on a few seconds later. |
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There was a Pop-Sci(IIRC) article awhile ago about a "hot bottle": attached to the cooling system it uses a heat pump to fill a thermos full of some molten salt or other, so when you want to heat your block you use that which heats coolant, etc. |
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I too, have suffered frustrating engine start faiures in excessivly cold climates. I came up with a rather unusual design which was inspired by a mechanic I knew. He used a 55 gallon oil drum filled with hot coolant/water mix he built a wood fire under...then hooked up a small electric pump and a few hoses via two way valves to the engine radiator (less t-stats, of course)...he just circulated hot coolant through the engine, slowly opening a by-pass valve to not shock the engine with too much heated coolant...This sytem worked great and guaranteed a warm engine start. I did not think much of the system at the time because it was so cumbersome...but, the bottom line was...it worked. |
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My modification, I had bult a few years later was along the same lines but used a butane fueled heater, rather like the kind you find on a turkey fryer, on a closed circuit using a small pressure pressure vessel and hooked through the heater core tubing and a powered by a 12 volt pump. The closed system was in no danger of over pressure, since it worked like a "double boiler"...that is, the tank sat in a bath of hot water in an open pot...the whole thing fit on a hand cart and would transport easily in the bed of a pickup...it would take about a half hour to warm an engine block but did not do well in windy conditions...We used it several times in New Mexico to heat up engine blocks not only on trucks but also fork lifts and back hoes. I'm sure it could easily be reduced in size and portability, since this one was built on the fly with cheap, handy parts. And, some pieces of equipment had to be modified by installing tees in the coolant lines (more difficult with units with no heaters). I must admit, we never used it in temps as low as minus 34...brrrrr-r-r-r-. Now that's cold! and, my system was not easily or quickly cobbled together in an emergency situation....we took some time to build it right....you don't want hot water escaping out onto crew members. |
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But, with the right designers and well thought out parts, a good system could be built right on the unit itself perhaps fueled diretly from the vehicle fuel tanks. |
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I've been out of the business for many years and have no idea what devices are out there now...probably someone has one you can order from a catalog. |
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Well.. (-) if you're talking lead-acid batteries. They perish quickly under that kind of use. & they perform very poorly at low temperatures.
But NiMH or Li-ion batteries might be OK, if you have deep pockets. Energy requirement is much greater than [MaxwellBuchanan] suggests. 10C doesnt go far when its -30C out, 100kg is optimistic, and the whole show is losing heat more-or-less madly, depending on the heater placement. Lets see.. NiMH's are about 250kJ/kg, so a 5-10 kg battery might do. I would use high power heater(s) for a short time prior to starting.
Overall, though, this sounds like a job for a fuel operated heater. |
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yeah, there's a lot of mean little towns in Montana.. Wolf Point springs to mind |
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Certainly baked in commercial/military vehicles. They have a diesel burner/pump combined and run the engine coolant around, heating it steadily. |
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This way, there's only a small pump and fan (for the burner to breathe) to run, easing up life on the vehicle's battery. |
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This type of device is permanently fitted to a vehicle though. |
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I'm sure a petrol stove is doable as well. There was a timer fitted also. |
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