Engine coolant thermos - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• Engine coolant thermos by jtanguay on 21 Feb, 2006 19:22
• I read up on some kids who had this idea.
  
  I think this is an excellent idea for us dieselers.  I mean, our engines don't perform properly until they are fully warmed up (and can take quite a while when its cold out).  
  
  The thermos could sit in the trunk of the car- extremely well insulated - lines going from the engine.  It would be sort of like the system to warm wvo systems.  The thermos could also have a heating element w/temp sensor for plug in overnight (save money big time than using a block heater which draws a lot of power plus most of the heat just radiates out into the cold)
  
  Even if the coolant was lukewarm (say after an 8 hour shift at work) it would mean easier starting and less engine wear due to the cold starting temps. (and I'm not a fan of letting my car warm up for 5 minutes waiting to get home and STILL not getting heat out of it)
  
  Any ideas on how to construct this?  My guess would be to use something that does not transmit heat very well.  Possibly ceramic?  or like a plain glass thermos with neoprene insulation?  I'd say at least 2-3 gallon thermos tank for the more colder regions.
  
  edit:  this system would not be solely geared towards winter either.  Just think of a cool summer night.  The only issue I can foresee is the extra heat from having an extra 3 gallons of water. The radiator would be overworked on hot days trying to cool the extra liquid, or would it?  My guess is that the rad fan would come on less frequently, but when it did come on it would be left on for further lengths of time, possibly burning something out.  Maybe some sort of thermostat could be applied so that the hot thermos tank water would be disengaged from the main coolant system when it reached 87 degrees celcius or so?
• #1 by bhtooefr on 21 Feb, 2006 19:43
• Actually, the Prius uses a system much like this to avoid cold starts, from what I've read.
  
  Anyway, what's wrong with a Zerostart? I'm gonna install mine, and it's gonna be NICE once I do so
• #2 by QuickTD on 21 Feb, 2006 20:28
• BMW has used such a system in the 7 series for some time. Of course, the idea with the 7 is to get instant heat for improved passenger comfort. They use a super insulated canister filled with a wax that melts at engine operating temperature. The wax surrounds a coolant heat exchanger allowing the coolant to heat the wax and vice versa. The change of state from solid to liquid and liquid to solid can store far more energy than just a heated jar of coolant, making the unit exceptionally small for its heat storage capacity. I believe the BMW unit is not much larger than a small muffler, though I've never seen one myself. There would be no reason to decouple such a system from the engine in any weather, it would speed warmup in the summer as well. The BMW unit is isolated from heat loss and thermosiphoning by a pair of floating ball type check valves, similar to those used on hot water heaters. All very interesting stuff...
  
   If equipped with a small electric pump (like a VR6 after run pump), such a setup could be used as a block heater for those unfortunate enough to be stuck out of reach of power...
• #3 by jtanguay on 22 Feb, 2006 05:07
• I'm liking the heat exchanging idea with the wax.   The problem with the zerostart is that you need a plug-in.   There are plugs where I work in the parking garage, but I'm not sure if they could handle a block heater for a lengthy period of time (8 hour shift).  
  
  This system would simply be the best for say going out somewhere for an hour, and then coming back to a nice warm car without the need for a plug-in.
• #4 by jtanguay on 23 Feb, 2006 18:40
• Quote from: "bhtooefr"

  Actually, the Prius uses a system much like this to avoid cold starts, from what I've read.
  
  Anyway, what's wrong with a Zerostart? I'm gonna install mine, and it's gonna be NICE once I do so

  
  
  I heard that the prius can store 3 liters of hot coolant for 3 days?  how the hell...  that is a very advanced system for sure  that beats zerostart instantly!!!
• #5 by lord_verminaard on 24 Feb, 2006 05:32
• The TDI's have like 3 glow plugs in a coolant junction right next to the head, which I've heard is to help warm-up.  Probably wouldnt be too hard to rig up something like that on an IDI.  
  
  Brendan
  84 Scirocco 8v
  00 Camaro L36 M49
• #6 by bhtooefr on 24 Feb, 2006 06:28
• The stick-shift ones do.
  
  The automatics apparently heat the coolant up quickly enough because of the fact that the ATs heat up their tranny fluid REALLY quickly.
• #7 by jtanguay on 24 Feb, 2006 14:35
• Quote from: "lord_verminaard"

  The TDI's have like 3 glow plugs in a coolant junction right next to the head, which I've heard is to help warm-up.  Probably wouldnt be too hard to rig up something like that on an IDI.

  
  
  That coolant-glow system is alright, but it puts a big load on the alternator as well as the battery.  Plus going through 3 glowplugs every year or two (having to re-install them too) doesnt sound very appealing.  I'm quite surprised VW has not adopted the coolant thermos idea.
  
  The coolant thermos would pretty much eliminate the need for block heating, and make starting in extreme cold possible as well as smoother for our old engines (or even new ones that we would like to preserve)
  
  I'm going to be building my coolant thermos pretty soon and attempt to reproduce the toyota prius' system.  I might even try to hook a feature from a remote starter to get the 12v pump to pump the warm coolant through the engine as I walk to my car.
  
  parts needed - stainless steel container (no idea where I will find this, and will most likely need to find something more abundant and cheap.)
  
  to create the vacuum I will need two containers, one bigger and one smaller (of course)  the large container will need a lid and some sort of pressure relief valve.  I will heat the container with the valve open and get as much of the air out as possible.  (poor mans vacuum- if i can find something better... i will use it).  The thermal medium is still yet to be determined.   Either a wax or an oil.
  
  -1 or 2 heat exchangers (depending on size) that fit inside the smaller container in my thermos.
  
  -12v water pump at princess auto maybe, or an automotive pump $$ on ebay ?
  
  -Temperature sensor with A/C relay to power coolant pump/heater for cycle.  still need to find something!
  
  -engine coolant pump/heater - used for short cycle to keep the engine coolant temp topped up during long period storage (overnight)
  
  -neoprene material - possibly cover the coolant reservoir as well as pipes going to and from the engine. (will help prevent thermosyphoning)
  
  I've also considered just covering the entire engine with neoprene.  I don't see any issues with this until its time to do engine work.  The rad will be doing all of the cooling anyways.  Maybe engine oil or diesel oil could damage the neoprene but thats it.
• #8 by bhtooefr on 24 Feb, 2006 18:29
• Quote

  but it puts a big load on the alternator

  
  
  ...putting more load on the engine, causing it to heat even faster.
• #9 by fatmobile on 24 Feb, 2006 22:00
• I wonder if this could be a shock to the engine ... being cold and having hot fluid pumped into it.
   The block heater heats the engine up slowly.
   Finding a way to do this and warm it up slowly would be something to concider.
• #10 by jtanguay on 25 Feb, 2006 15:30
• Quote from: "fatmobile"

  I wonder if this could be a shock to the engine ... being cold and having hot fluid pumped into it.
   The block heater heats the engine up slowly.
   Finding a way to do this and warm it up slowly would be something to concider.

  
  
  hmmm yes it could pose a significant problem if boiling water was pumped into the engine, but I believe the cold oil would counteract any type of 'shock' the engine might receive (using the oil cooler to warmup the oil).  
  
  My plan is to attempt to eliminate freezing coolant during cold start-ups.  Our engines could run with a lesser CR with this type of system installed  :wink: just imagine the possibilities !!
• #11 by Baxter on 25 Feb, 2006 15:46
• The VW Sharan/Seat Alhambra and the Ford Galaxy have a auxilliary water heater just in front of the left hand rear wheel.
  They have an extra heater in the back, by the time the coolant gets there on a TDI motor it aint too warm, the Eberspacher warms it up a little.
  There a loads in scrap yards here. Can be used in conjunction with a timer and set to come on an hour or so before a journey so your cooling system is warm and your windows are clear.
• #12 by jtanguay on 25 Feb, 2006 16:47
• http://www.vfaq.net/FAQ-engine.html
  
  thats the site that says the toyota prius can store near boiling temp water for up to 3 days... (is that some kind of joke? most thermos' can barely do 24 hours!)