How's your idle? (Just some idle blabbing)

[Unforgiven]

Hmm, seeing stats like this makes me hunger for that blasted ScanGauge...lol

[HypermilerAX]

Measurement method:
Fuel pumped out of a bottle and weighed with 0.1 g precision. The scale was oscillating a lot though (vibrations?).

I ran the engine for a minute or so in order to expel all the air. I waited for the engine to cool down completely. I noted the value every 10 seconds the first 10 minutes and then 30 seconds until 15 minutes. I attached the raw graph (spaces are due to scale shut down, values in ml/h) and another minute by minute with engine temps but here are the most interesting values:

Avg over first minute : 976 ml/h
2nd minute : 585,5 ml/h
3rd : 571,1 ml/h
...
Avg from 13:00 to 15:30 : 393,3 ml/h

Wow, that is low. I'll think twice before EOCing.

After 15 minutes of idling, the engine wasn't completely warm (especially oil temp) so I will do another test right after a (long) trip.

[cRiPpLe_rOoStEr]

No wonder my uncle says that it's not worth to shut down an old-school Diesel for short times. Well, maybe the newer-generation ones with direct injection and more advanced controls, due to their lower internal temperatures, tollerate more EOC than an IDI does.

[HypermilerAX]

271,4 ml/h over 6 minutes with completely warmed up engine. That seems credible, I see 0.3/0.4 l/h over the net for mid-sized diesel engines.

[ever_green]

Originally Posted by HypermilerAX

271,4 ml/h over 6 minutes with completely warmed up engine. That seems credible, I see 0.3/0.4 l/h over the net for mid-sized diesel engines.

wow thats low. for my 2.5L engine its exactly 1L/H.

[HyperMileQC]

In my Insight when fully warmed up (92°C) its around 0.15 - 0.2 L/h. But in general it doesn't make any noise and its 0 L/h .

[slowmover]

I would assume .33 to 1.0/gls hour for most any motor, up to and including the 15L Cummins in my work Peterbilt.

But, what would be the point of idle rpm fuel consumption measurements? I'd think "engine wear without work performed" would be more useful way of thinking about it (and there are scenarios where providing heating or cooled air for passengers is if high value). Engines are designed with a number of hours of economic life as a gauge. Right down to a two-stroke weedeater (cheap one at 250/hrs) to the light duty diesel in my pickup (10,000-hrs) not just commercial calculations.

The percent idle time is a recognized metric. A mph averageotherwise. On my pickup brand engine if one keeps that average at 27-mph or higher then FE is relatively good. The 10K engine life expectation (mean time between overhaul) is predicated on a 35-mph average.

The "usefulness" of engine idle fuel consumption [EIFC] ought to be related, somehow, to performance (achieving work). In a hurricane evactuation, for example, I'd expect that -- small to large -- personal vehicles are going to do no better than 3-5/mpg in bumper-to-bumper traffic. EIFC is not important in this, it is fuel capacity that matters far more (and, as note, the ability to travel 150-miles inland to be able to re-fuel from undisturbed stocks).

On the work Peterbilt we engage "high idle" if idling is to be extended past five minutes per the manufacturer instructions. Engine longevity/reliability far exceeds reduced consumption at this low level.

So, what am I missing as to importance, here?

.

[serialk11r]

According to Torque and my Ebay OBDII scanner, 0.18 gph fully warmed up coolant at 680rpm idle for a pre 2003 Toyota 1ZZ-FE (1794cc). I didn't measure it after driving a while though (hotter oil, should have slightly less friction), but I'm using 5W-20 instead of 10W-30 so that cuts the difference a bit.

I am getting the intake cam duration increased which would lower the vacuum, hoping that can cut it to like 0.16 gph :O I want to get an Apexi Power FC and play with the idle, I feel like the car should be able to idle okay at 500rpm without too much misfiring, if the gph scales proportionally that would be a fantastic 0.13ish idle. The aftermarket ECU would also let me reduce the faster idle that comes on with AC or higher electrical loads.

[Ecky]

Honda B18B1 (1.8L from 90's Integra):

750rpm
0.22gph

[ksa8907]

In the summer and a fully warm engine.
3.2 v6 .45 gal/h