Insulating the thermos?

Its already insulated. I don't think adding more insulation would help much if any at all.

 

Hi All,

Well insulating the thermos might not do too much. The greatest leakage from heat storage devices are the lines going in and out of the devices. So, insulating the hoses to and from the thermos might have an effect. Maybe not so much down there in the mid-Atlantic coastal areas, but certainly around here when its down below 0 F.

 

It's not going to help, unless you use tiles from the Space Shuttle.

Tom

 

What is the thermos? And where is it? And what does it do?

 

The thermos is on the lower left(driver's side) side of the car near the bumper. It holds about 3 quarts of coolant that is pumped out of the cooling system when the car is powered down. The thermos is heavily insulated and can keep the temperature of the stored coolant warm(somewhat above ambient temp) for as long as three days. When the car is powered up and the ICE starts, the contents of the thermos are returned to the cooling system to help with a faster warm-up time. There is probably a much better explanation but that's about as detailed as I can put it. Hobbit? Fire Engineer? John1701a?

 

I'd have to check, but I seem to recall that the contents of the thermos are not pumped into the engine if it is colder than the engine. I recall that the control system is fairly clever about when to swap coolant into and out of the thermos.

Tom

 

Last summer when I would start out in the mornings, my coolant temp would be at 150F(SG2) with the EBH plugged in. When the ICE would start, the temp would drop to ~130F but would rise to 150F and beyond within 1/4 mile. This would seem to suggest the thermos emptying and cooling off the coolant in the ICE?

 

Sounds conclusive to me.

Tom

 

Japanese Prius does not have thermos, and we see the same temperature drop on engine starting after heating by EBH.

Anyway, following presentation shows the pump starting condition is less than 104F coolant temp.
John's Stuff - Toyota Prius - 2004 Tech Presentation 38

Ken@Japan

 

I have wondered the same thing! I notice the engine temp dropping after the EBH has pre-warmed the beast as the cooler thermos-stored fluid is pumped in. Either we need to use a Thermos-Block-Heater, or a cut away switch to prevent colder coolant from negating the effects of the EBH.

The Thermos may be well insulated, but more wouldn't hurt? Anybody know the R factor of the coolant storage device? Is it truly a Thermos with a vaccuum bottle?

Lee

 

The thermos is made by Tiger, a very famous thermos manufacturer.
Tiger Corporetion
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There is a Technical Review article by Denso written in Japanese, but pictures and graphs are shown in English.
http://www.denso.co.jp/DTR/vol10_no1/dissertation13-itp5.ps.pdf
A performance graph is shown at Fig.5 on page 3, approx. 65C(149F) after 24 hours.

Ken@Japan

 

The coolant temp sensor is located close to the EBH.
The cold coolant still remains in other engine block area, then it is mixed up after starting, I believe.

Ken@Japan

 

My coming Prius does not have this thermo system(europian model).Does anyone have any idea how much it cost to purchase it from US,new or used one?Is it difficult to install and does it need special software to make it work.

That sounds so cool to me especially because i´m very lazy to use ebh.

 

The technical review that Ken1784 posted on the thermos and water pump is fascinating. Unfortunately I do not read Japanese. However, I believe I get the general idea from the pictures and tables. I have a few questions/comments for Ken or whoever might be able to answer:

1. Is there a possibility of getting the article translated into English?

2. The article was written in 2005; have the design improvements such as the support pin on the inner tank of the thermos and the magnetic coupling/orbital welding on motor/pump been implemented on the 2008 vehicles?

3. The non-mixture plate is a great idea! Very nice.

 

I could not find the English version.
Instead of that, please refer to page-10 and later of following article.
http://www.autoshop101.com/forms/Hybrid04.pdf

I believe the review is written for the development efforts on the 2004 model.
The original "household use" one does not have support pin on Fig. 10.
The developed one has the support pin and it can be seen on the 2004 Prius.

Ken@Japan