Go Back   EcoModder Forum > EcoModding > Hypermiling / EcoDriver's Ed
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 07-14-2017, 05:27 AM   #1 (permalink)
Master EcoModder
 
JockoT's Avatar
 
Join Date: Jun 2017
Location: Scotland
Posts: 654

All That Jazz - '06 Honda Jazz i-DSI S
Team Honda
90 day: 48.72 mpg (US)
Thanks: 36
Thanked 126 Times in 94 Posts
Intake Air Temperature.

As I struggle to get to grips with my ScanGauge I was wondering why I would want to know the Intake Air Temperature? I have no control over it, as it is dependent on ambient temperature, so why would I want to follow it. Or is it just something that OBM II can display, so ScanGauge do!

__________________
People Think They Are Thinking When They Are Merely Rearranging Their Prejudices


  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 07-14-2017, 09:35 AM   #2 (permalink)
Administrator
 
Daox's Avatar
 
Join Date: Dec 2007
Location: Germantown, WI
Posts: 10,334

CM400E - '81 Honda CM400E
90 day: 39.62 mpg (US)

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

Daox's 04 Civic - '04 Honda Civic DX
90 day: 42.25 mpg (US)

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

Swarthy - '14 Mitsubishi Mirage DE
Thanks: 1,844
Thanked 2,013 Times in 1,236 Posts
OEMs use intake air temperature to control the fuel injection and ignition timing on the engine. The Scangauge gives you access to any sensor that the ECU has available. You can use the intake air temperature for troubleshooting (bad sensor, short in the wiring, etc), or you can use it for monitoring a fuel economy modification like a warm air intake, or performance modification like a cold air intake.
__________________
Current project: Heating the manual trans with engine coolant
  Reply With Quote
Old 07-14-2017, 09:55 AM   #3 (permalink)
Master EcoModder
 
JockoT's Avatar
 
Join Date: Jun 2017
Location: Scotland
Posts: 654

All That Jazz - '06 Honda Jazz i-DSI S
Team Honda
90 day: 48.72 mpg (US)
Thanks: 36
Thanked 126 Times in 94 Posts
I appreciate that the fuel injection system uses the air temp to get the correct fuel density, I just wondered why ScanGauge gave the option of displaying it. There are lots of other things they allow you to scan but don't display on a gauge. Regarding warm air intake, I was always under the impression that a colder air intake temperature gave better performance and fuel economy. I read a thesis on air intake temperature and the published results clearly showed that increasing the inlet air temperature caused the fuel consumption to get worse. I am open to persuasion, however.
__________________
People Think They Are Thinking When They Are Merely Rearranging Their Prejudices


  Reply With Quote
Old 07-14-2017, 10:32 AM   #4 (permalink)
Administrator
 
Daox's Avatar
 
Join Date: Dec 2007
Location: Germantown, WI
Posts: 10,334

CM400E - '81 Honda CM400E
90 day: 39.62 mpg (US)

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

Daox's 04 Civic - '04 Honda Civic DX
90 day: 42.25 mpg (US)

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

Swarthy - '14 Mitsubishi Mirage DE
Thanks: 1,844
Thanked 2,013 Times in 1,236 Posts
I'd be interested in reading this paper if you can find it.

On gasoline cars, warm air does a couple things, some are positive and others are negative. Mainly, it reduces the density of the air coming into the engine. This essentially doesn't allow the engine to make as much power. The lower output of the engine therefore requires increased engine load to do the same work. Increased engine load causes a reduction in pumping losses which increases efficiency. This is the same reason smaller engines get better fuel economy than larger ones (all else being equal). Warmer air also speeds up the combustion process. This is a good thing to a point, but if you get too much heat in there, you start having to alter ignition timing which can hurt efficiency.

Thats kind of the short answer. Others can fill in with what I haven't remembered off hand.
__________________
Current project: Heating the manual trans with engine coolant
  Reply With Quote
The Following 2 Users Say Thank You to Daox For This Useful Post:
JockoT (07-14-2017), redpoint5 (07-14-2017)
Old 07-14-2017, 11:40 AM   #5 (permalink)
V8 guy
 
oil pan 4's Avatar
 
Join Date: Jul 2011
Location: NewMexico (USA)
Posts: 5,016

Sub - '84 Chevy Diesel Suburban C10
SUV
90 day: 19.5 mpg (US)

camaro - '85 Chevy Camaro Z28

Riot - '03 Kia Rio POS
Team Hyundai
90 day: 30.21 mpg (US)

Bug - '01 VW Beetle GLSturbo
90 day: 26.43 mpg (US)

Sub2500 - '86 GMC Suburban C2500
90 day: 11.95 mpg (US)
Thanks: 107
Thanked 1,179 Times in 867 Posts
Cold air gives better power and fuel economy on diesel.
On a gas engine cold air gives more power and typically less power.
And you can control the intake air temperature.
Of course any one trying to sell you a cold air intake is going to tell you there is no negative side effects.
Typically, not always, cold air reduces fuel economy.
__________________
1984 chevy suburban, custom made 6.5L diesel turbocharged with a Garrett T76 and Holset HE351VE, 22:1 compression 13psi of intercooled boost.
1989 firebird mostly stock. Aside from the 6-speed manual trans, corvette gen 5 front brakes, 1LE drive shaft, 4th Gen disc brake fbody rear end.
  Reply With Quote
Old 07-14-2017, 12:27 PM   #6 (permalink)
EcoModding Newb
 
redpoint5's Avatar
 
Join Date: Aug 2010
Location: Oregon
Posts: 2,994

Acura TSX - '06 Acura TSX
90 day: 31.25 mpg (US)

Lafawnda - '01 Honda CBR600 F4i
90 day: 47.32 mpg (US)

Big Yeller - '98 Dodge Ram 2500 base
90 day: 21.82 mpg (US)

Prius Plug-in - '12 Toyota Prius Plug-in
90 day: 79.06 mpg (US)

Mazda CX-5 - '17 Mazda CX-5 Touring
Thanks: 1,154
Thanked 916 Times in 613 Posts
Quote:
Originally Posted by oil pan 4 View Post
On a gas engine cold air gives more power and typically less efficiency.
.
__________________
Gas and Electric Vehicle Cost of Ownership Calculator







Give me absolute safety, or give me death!
  Reply With Quote
Old 07-14-2017, 12:31 PM   #7 (permalink)
Master EcoModder
 
JockoT's Avatar
 
Join Date: Jun 2017
Location: Scotland
Posts: 654

All That Jazz - '06 Honda Jazz i-DSI S
Team Honda
90 day: 48.72 mpg (US)
Thanks: 36
Thanked 126 Times in 94 Posts
I realise you can change the air intake temperature, I have had cars where the air cleaner has a summer and winter position. But how and why would I adjust it on the move?
__________________
People Think They Are Thinking When They Are Merely Rearranging Their Prejudices


  Reply With Quote
Old 07-14-2017, 12:58 PM   #8 (permalink)
Cyborg ECU
 
California98Civic's Avatar
 
Join Date: Mar 2011
Location: Coastal Southern California
Posts: 4,171

Black and Green - '98 Honda Civic DX Coupe
Team Honda
90 day: 60.54 mpg (US)

Black and Red - '00 Nashbar Custom built eBike
90 day: 3671.43 mpg (US)
Thanks: 1,486
Thanked 1,162 Times in 771 Posts
Quote:
Originally Posted by JockoT View Post
I realise you can change the air intake temperature, I have had cars where the air cleaner has a summer and winter position. But how and why would I adjust it on the move?
The why: if intake air is not very high, the theory goes, the beneifit to fuel economy from decreased pumping losses cannot occur. If it is too high, some fear engine damage. I typically went for 30-50*F over ambient.
The how: some guys have a shutter system on the grill, or a redirect system on the intake tube. Both are to allow selecting for hotter or cooler intake air (often using a solenoid or some sort of wire-pull switching mechanism).

I have gained a little more skepticism about my warm air intake in the last year, since I was forced to run without it for a while and was unclear what affect its removal had on my FE (possibly it got better, but there are too many variables to feel confident of that educated guess). So, I too would love to see the thesis on warm air and fuel efficiency that you mentioned. Can you find it?

james
__________________


See my car's mod & maintenance thread and my electric bicycle's thread for ongoing projects. I will rebuild Black and Green over decades as parts die, until it becomes a different car of roughly the same shape and color. My minimum fuel economy goal is 55 mpg while averaging posted speed limits. I generally top 60 mpg. See also my Honda manual transmission specs thread.

  Reply With Quote
Old 07-14-2017, 02:06 PM   #9 (permalink)
Master EcoModder
 
JockoT's Avatar
 
Join Date: Jun 2017
Location: Scotland
Posts: 654

All That Jazz - '06 Honda Jazz i-DSI S
Team Honda
90 day: 48.72 mpg (US)
Thanks: 36
Thanked 126 Times in 94 Posts
Quote:
Originally Posted by California98Civic View Post
I too would love to see the thesis on warm air and fuel efficiency that you mentioned. Can you find it?
I downloaded the pdf
EFFECTS OF AIR INTAKE TEMPERATURE ON THE FUEL CONSUMPTION AND EXHAUST EMISSIONS OF NATURAL ASPIRATED GASOLINE ENGINE | Abdullah | Jurnal Teknologi

__________________
People Think They Are Thinking When They Are Merely Rearranging Their Prejudices


  Reply With Quote
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com