Go Back   EcoModder Forum > EcoModding > General Efficiency Discussion
Register Now
 Register Now

Reply  Post New Thread
Submit Tools LinkBack Thread Tools
Old 04-09-2011, 07:58 PM   #1 (permalink)
Left Lane Ecodriver
RobertSmalls's Avatar
Join Date: Aug 2008
Location: Buffalo, NY, USA
Posts: 2,257

Prius C - '12 Toyota Prius C
Thanks: 79
Thanked 284 Times in 197 Posts
Engine friction torque and power loss quantified

Information Bridge: DOE Scientific and Technical Information - Sponsored by OSTI

Here's an SAE technical paper that reads a bit like a Honda press release, but it's full of good technical information about the Insight.

Page 8 has a plot that gives engine friction torque at 1500RPM for a number of different engines. The Insight's appears to be about 10Nm at 1500RPM, i.e. 2.1HP. That's about half the value for their baseline 1.8L engine.

It means that engine friction is about half as large as road load at 45mph, which explains why the Insight's EV mode is so disappointing. It's also a reminder of how important it is to shut down your engine when it's not in use.

  Reply With Quote
The Following 3 Users Say Thank You to RobertSmalls For This Useful Post:
Christ (04-10-2011), Frank Lee (04-09-2011), roflwaffle (04-10-2011)
Alt Today
Popular topics

Other popular topics in this forum...

Old 04-09-2011, 08:49 PM   #2 (permalink)
Frank Lee's Avatar
Join Date: Jan 2008
Location: up north
Posts: 12,761

Blue - '93 Ford Tempo
Last 3: 27.29 mpg (US)

F150 - '94 Ford F150 XLT 4x4
90 day: 18.5 mpg (US)

Sport Coupe - '92 Ford Tempo GL
Last 3: 69.62 mpg (US)

ShWing! - '82 honda gold wing Interstate
90 day: 33.65 mpg (US)

Moon Unit - '98 Mercury Sable LX Wagon
90 day: 21.24 mpg (US)
Thanks: 1,584
Thanked 3,546 Times in 2,215 Posts
Pretty much everything has gone to rollers in the valvetrain now.

The piston dimpling is a new one for me... but I confess, I don't get the reasoning as cylinder cross-hatching has been used forever for the same function (as I understand it or misunderstand it).

  Reply With Quote
Old 04-10-2011, 03:25 AM   #3 (permalink)
Master EcoModder
roflwaffle's Avatar
Join Date: Dec 2007
Location: Southern California
Posts: 1,490

Camryaro - '92 Toyota Camry LE V6
90 day: 31.12 mpg (US)

Red - '00 Honda Insight

Prius - '05 Toyota Prius

3 - '18 Tesla Model 3
90 day: 152.47 mpg (US)
Thanks: 349
Thanked 120 Times in 79 Posts
I think the point of either is that there is more lube per unit surface area to avoid dry spots, up to some point where the surfaces become too rough and the lubricated friction starts to increase.
  Reply With Quote
Old 04-10-2011, 06:32 AM   #4 (permalink)
Moderate your Moderation.
Join Date: Nov 2008
Location: Troy, Pa.
Posts: 8,919

Pasta - '96 Volkswagen Passat TDi
90 day: 45.22 mpg (US)
Thanks: 1,369
Thanked 430 Times in 353 Posts
Re: cross hatching- on old splash lubed briggs engines, one of the tricks we used to use to keep higher hp engines running longer was lightly scoring the outside of the piston below the ring lands, so that oil mist in the crankcase would more really sick to the rough surface.

Likewise, a mild polish to the exposed areas of the crank and rod would help keep oil off them, reducing rotating/reciprocating mass.
"ʞɐǝɹɟ ɐ ǝɹ,noʎ uǝɥʍ 'ʇı ʇ,usı 'ʎlǝuol s,ʇı"

  Reply With Quote
Old 04-10-2011, 01:29 PM   #5 (permalink)
...beats walking...
Join Date: Jul 2009
Location: .
Posts: 6,190
Thanks: 179
Thanked 1,522 Times in 1,123 Posts
...analogy: piston "...cross-hatching..." is to oiling as "lightly sanding" is to good paint surface preparation...they both provide "holding" power (surface area) for the applied liquids, oil and wet paint.

Last edited by gone-ot; 04-10-2011 at 03:13 PM..
  Reply With Quote
Old 04-10-2011, 01:33 PM   #6 (permalink)
Moderate your Moderation.
Join Date: Nov 2008
Location: Troy, Pa.
Posts: 8,919

Pasta - '96 Volkswagen Passat TDi
90 day: 45.22 mpg (US)
Thanks: 1,369
Thanked 430 Times in 353 Posts
Radially grooving the skirts (around the circumference of the piston, just below the ring groove, supposedly makes the oil sweep more effective, by giving the oil an area in which to be displaced from the cylinder wall.

"ʞɐǝɹɟ ɐ ǝɹ,noʎ uǝɥʍ 'ʇı ʇ,usı 'ʎlǝuol s,ʇı"

  Reply With Quote
Reply  Post New Thread

Thread Tools

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