Go Back   EcoModder Forum > EcoModding > EcoModding Central
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 07-31-2018, 05:30 PM   #71 (permalink)
EcoModding Lurker
 
Join Date: Oct 2012
Location: Toronto, ON
Posts: 5

Bimmer - '02 BMW 325ci
90 day: 23.79 mpg (US)
Thanks: 5
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by Vman455 View Post
Aqueous ethylene glycol decomposes into carbon monoxide and diatomic hydrogen (hydrogen gas) if it gets hot enough.
At what temp? Water would also split into oxygen and hydrogen if you heat it to 2000'C.

  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 07-31-2018, 07:51 PM   #72 (permalink)
Administrator
 
Daox's Avatar
 
Join Date: Dec 2007
Location: Germantown, WI
Posts: 11,166

CM400E - '81 Honda CM400E
90 day: 51.49 mpg (US)

Daox's Grey Prius - '04 Toyota Prius
Team Toyota
90 day: 49.53 mpg (US)

Daox's Insight - '00 Honda Insight
90 day: 64.33 mpg (US)

Swarthy - '14 Mitsubishi Mirage DE
Mitsubishi
90 day: 56.69 mpg (US)
Thanks: 2,464
Thanked 2,535 Times in 1,529 Posts
Quote:
Originally Posted by engineered View Post
Since this has been revived, why not use a 12V block heater and/or 12V oil pan heater to heat up the fluids? They could be used manually or controlled automatically to come on with the car and turn off at a certain coolant temp (or from the tstat).
The purpose of this thread is to use 'free' exhaust heat to speed up the warming of the engine to decrease fuel consumption.

A block heater does work, if you have 110V power. If you don't, this device can and will help.

Using 12V power from the alternator will actually increase fuel consumption, not decrease it. So that kind of defeats the purpose we are going for at least, though you would get heat quicker. VW actually does do this with their TDI engines to get them up to temperature faster.


Quote:
How would coolant water (and glycol) degrade? It doesn't break down like motor oil. I'm mean if you overheat it, it would eventually vaporize, but 98'C water is always going to be the same water.
Vman is correct. Ethlyene glycol is only supposed to be good to 250F / 121C. It will start cracking at around 285F / 140C according to this paper (page 16). That is certainly achievable by warming the coolant with the exhaust. I'm not sure if the water will start boiling out before that point or not, but if it does, thats not good either.
__________________
Current project: A better alternator delete
  Reply With Quote
The Following User Says Thank You to Daox For This Useful Post:
Xist (08-03-2018)
Old 07-31-2018, 08:03 PM   #73 (permalink)
EV OR DIESEL
 
Join Date: Dec 2007
Location: South Louisiana
Posts: 1,745

FarFarfrumpumpen - '03 Volkswagen Jetta Wagon GLS Premium

Quorra - '12 Tesla Model S P85
Thanks: 57
Thanked 105 Times in 81 Posts
Send a message via AIM to dremd
I’d also note that the quality of 12volt energy is limited. Even with VW’s large battery and alternator the difference in warm up time isn’t noticeable to the average driver with the system disabled. The gen 3 Prius warm up time is genuinely impressive until you move to EV’s and expect heat instantly.
__________________
2012 Tesla Model S P85
2013 Nissan LEAF SV totaled by now deceased intoxacated driver.
2012 Nissan LEAF SV
6 speed ALH TDI Swapped in to a 2003 Jetta Wagon
  Reply With Quote
Old 07-31-2018, 09:29 PM   #74 (permalink)
EcoModding Lurker
 
Join Date: Oct 2012
Location: Toronto, ON
Posts: 5

Bimmer - '02 BMW 325ci
90 day: 23.79 mpg (US)
Thanks: 5
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by Daox View Post
The purpose of this thread is to use 'free' exhaust heat to speed up the warming of the engine to decrease fuel consumption.

A block heater does work, if you have 110V power. If you don't, this device can and will help.

Using 12V power from the alternator will actually increase fuel consumption, not decrease it. So that kind of defeats the purpose we are going for at least, though you would get heat quicker. VW actually does do this with their TDI engines to get them up to temperature faster.


Vman is correct. Ethlyene glycol is only supposed to be (page 16). That is certainly achievable by warming the coolant with the exhaust. I'm not sure if the water will start boiling out before that point or not, but if it does, thats not good either.
I agree that the exhaust heat is 100% free, while a 12V heater is not. I guess I was thinking people were looking to heat the engine up quicker to reach operating temps faster.

Quote:
Originally Posted by dremd View Post
Id also note that the quality of 12volt energy is limited. Even with VWs large battery and alternator the difference in warm up time isnt noticeable to the average driver with the system disabled. The gen 3 Prius warm up time is genuinely impressive until you move to EVs and expect heat instantly.
With a 100A alternator, a 12V heater could put out more than 1kW of heat into the coolant, which is very little compared to an idling engine, say 5hp (3.7kW), so the engine is already putting 4x more heat into the fluids. Still, 1kw heater would add 27% more heat, but barely noticeable to a driver. Gently driving around using 100hp(75kW) would put out 75x more heat and make the 12V heater very insignificant.
  Reply With Quote
Old 08-01-2018, 09:36 AM   #75 (permalink)
EcoModding Lurker
 
Join Date: Jan 2017
Location: UK
Posts: 29
Thanks: 11
Thanked 15 Times in 9 Posts
Why complicate things. Just get an EGR cooler that has the valve built in. Then you just need a 12v vacuum pump to activate (based on the temperature sensing relay) to keep it open to let hot exhaust through during warmup. Then close it once up to temperature to stop it boiling the coolant in the egr cooler.
  Reply With Quote
Old 08-01-2018, 10:20 AM   #76 (permalink)
Administrator
 
Daox's Avatar
 
Join Date: Dec 2007
Location: Germantown, WI
Posts: 11,166

CM400E - '81 Honda CM400E
90 day: 51.49 mpg (US)

Daox's Grey Prius - '04 Toyota Prius
Team Toyota
90 day: 49.53 mpg (US)

Daox's Insight - '00 Honda Insight
90 day: 64.33 mpg (US)

Swarthy - '14 Mitsubishi Mirage DE
Mitsubishi
90 day: 56.69 mpg (US)
Thanks: 2,464
Thanked 2,535 Times in 1,529 Posts
I believe that is basically what the Borg Warner unit is. Only, it is electronically actuated, not vacuum actuated.
__________________
Current project: A better alternator delete
  Reply With Quote
Old 08-01-2018, 11:54 AM   #77 (permalink)
Master EcoModder
 
Ecky's Avatar
 
Join Date: Dec 2011
Location: Vermont
Posts: 4,370

Gaptooth (retired) - '00 Honda Insight
Team Honda
Gen-1 Insights
90 day: 54.26 mpg (US)

Such Fit - '07 Honda Fit Sport
90 day: 41.27 mpg (US)

Connect - '15 Ford Transit Connect XL
90 day: 21.26 mpg (US)

K-sight - '00 Honda K-sight
Team Honda
90 day: 43.14 mpg (US)

Aerocivic - '92 Honda Civic CX
90 day: 64.49 mpg (US)
Thanks: 2,198
Thanked 1,958 Times in 1,235 Posts
G1 Insight:




2006 Civic:




2008+ Accord, 2009+ TSX, 2012+ Civic Si:




2009+ Honda Fit:

  Reply With Quote
The Following 2 Users Say Thank You to Ecky For This Useful Post:
Daox (08-01-2018), Xist (08-03-2018)
Old 08-01-2018, 04:16 PM   #78 (permalink)
Master Ecomadman
 
arcosine's Avatar
 
Join Date: Nov 2010
Location: Chicago area
Posts: 1,146

sc1 - '98 saturn sc1
Team Saturn
90 day: 43.17 mpg (US)

Airplane Bike - '11 home built Carp line Tour

rans - '97 rans tailwind

tractor - '66 International Cub cadet 129

2002 Space Odyssey - '02 Honda Odyssey EX-L
90 day: 28.25 mpg (US)

red bug - '00 VW beetle TDI

big tractor - '66 ford 3400

red vw - '00 VW new beetle TDI
90 day: 58.42 mpg (US)

RV - '88 Winnebago LeSharo
90 day: 16.67 mpg (US)
Thanks: 20
Thanked 328 Times in 223 Posts
v8 engines of the sixties and earlier had a bimetallic spring and a flapper valve on one exhaust manifold that would divert exhaust through the intake manifold during warm up, nothing new here.

Just use an on-off valve to let coolant into your exhaust heat exhanger when cold, turn the valve off when warm. Have a check valve at the bottom to let coolant out of the exchanger when it boils. When it all boils out, no problem. Make it from welded stainless steel.

__________________
- Tony

  Reply With Quote
Reply  Post New Thread


Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
PBS takes the Hummer v Prius bait SVOboy Hybrids 51 05-19-2010 12:35 PM
Converting Exhaust Heat to Electricity SuperTrooper General Efficiency Discussion 13 03-20-2010 06:03 AM
Waste Heat from Exhaust TES111 EcoModding Central 35 11-21-2008 12:31 PM
Why does the heater core transfer heat from the coolant, not the exhaust? extragoode General Efficiency Discussion 23 10-17-2008 10:44 AM
Steam engine (from exhaust heat) iHero General Efficiency Discussion 23 09-08-2008 12:30 AM



Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com