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Old 02-04-2007, 08:16 PM   #1
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Terms: hot, warm, cold coast instead of FAS?

I've been finding CODFISH and FAS confusing. Partly that's because it doesn't apply to all types of cars. So, how about:

hot coast = moving, engine on and engaged, no pressure on gas pedal,
warm coast = moving, engine on but disengaged (neutral, or clutch depressed)
cold coast = moving, engine is off

And same sort of thing for sitting still:

hot sit = stopped, engine on, automatic is in drive
warm sit = stopped, engine on, automatic is in neutral or park
cold sit = stopped, engine off

Maybe for a manual tranny, hot sit would mean in neutral, clutch engaged, and warm sit would mean clutch disengaged. I'm thinking having the clutch engaged takes a tiny bit more fuel because some parts of the tranny are in motion even when in neutral.

So which of these, if any, is CODFISH, and which is FAS?
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Old 02-05-2007, 09:09 AM   #2
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bzipitidoo -

I am never really sure what the original acronyms mean, but I like the cold/warm/hot metaphor because it dovetails into computer terms for me.

Here's the FAQ :
http://www.gassavers.org/showthread.php?t=1088

Here are the definitions from the FAQ :

CODFISH = Coast On Demand Forced Ignition Shutoff
FAS = Forced Auto Stop. basicly turning the engine off. Be it on a coast or at a stop light. MPG is always better the less the engine runs.

If your terms catch on with other folks, they will end up here.

CarloSW2
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Old 02-05-2007, 11:05 AM   #3
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The FAQ's defintiion is what I mean about CODFISH. "Forced Ignition Shutoff" has to mean that while moving, the driver turns the ignition key to the off position to force the engine off, then rolls along in neutral. And I guess "on demand" is meant to allow for hybrids' ability to run electric only, with the ICE off, without the driver having to take any action with the ignition key. Not having driven a hybrid, I don't know, but perhaps with clever Pulse and Glide, you can coax the electronics into turning off the ICE during each glide, without having to work the ignition and gear shift, thus the "demand"?

One other way to coast: moving, engine off but still engaged. Call that "cool coast". Sounds like a lousy idea, unless you're going down a steep curvy mountain road and you're trying not to overuse your brakes, or your engine is designed so that when in that situation, it doesn't act like a speed sapping energy hungry air compressor.

Seems some terms overlap with P&G. I am guessing that P&G is effective because engines are most efficient when loaded as heavily as possible without overloading. Therefore one should gain kinetic energy during the pulse by speeding up at just the right rate, then shut off the engine and glide (cold coast), losing kinetic energy until the desired low speed is reached, then repeat. Suppose one gets (just pulling numbers out of the air) 20 mpg (or km per liter) during the pulse, then infinite FE during the glide, versus 30 mpg if driving at a constant speed. Even if the distance of the pulse is longer than the distance of the glide, might still save gas. (pulse mpg) * (pulse distance + glide distance)/ pulse distance = total mpg. Suppose one could do 2 units of distance glide for every 3 units of distance pulse. (Is that at all realistic? What if it's 1 glide per 5 pulse, or worse? On the other hand, maybe 2/3 normal FE is too pessimistic for a pulse, and it's more like 8/10 or 9/10?) Then at 20 mpg for the pulse, the total mpg would be 33 1/3, which is a bit better than the 30 mpg for steady state.
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Old 02-05-2007, 08:26 PM   #4
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Post I like this

Good ideas -- breaks it down into more user-friendly definitions.

What also confuses me, is engine temperature and the coasting or idling.

Some warm-up a car from a cold start by driving a little, shutting it down to coast, starting it, repeat, etc.

Would this be "Frigid Coast and Sit"?

I've found that the newer cars prefer to idle in-gear to warm-up, as opposed to being driven -- i.e. the TSX with its gadgetry. It seems to be a contradiction in philosophy, but instead of shutting down at a light (when its 30F or below), it traditionally has been better to let idle to get the emissions parts up to temp. Otherwise, it really sucks the gas down on even the slightest acceleration -- there's a compromise somewhere in there.

But the Integra would rather Cold Coast to a Cold Sit and start back up than idle. It tends to high-idle at 2000+ RPM in the bitter cold, I immediately start off in 1st (automatic), shift to 2nd (no pedal pressure) and it goes on its own idle. If I put it in D3, it has to reach 2500 before it shifts to 3rd (the same for 4th and D4). Once full coolant temp is reached, it acts normally -- except for the TC...

I found a Helms manual on the Integra and how the transmission is programmed (geez -- really complicated breakdown). The hill-logic control is bypassed when in D3. There was a hill that I just couldn't get it into 3rd until either hitting 3000+ RPM or hit the hill's crest. Shifting down to D3 fixed it. I also found that there's 3 points of engagement (full, half, and partial) for the TC and 2 converter sensors: A and B. The schematics listed series of conditions for the different lockup points.

Long story short -- if you really want to get to know your car for better FE -- find a shop manual. I never dreamed an automatic transmission was so complicated, for example, and what conditions need to be met for lockup.

RH77
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Old 02-05-2007, 08:46 PM   #5
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Quote:
Originally Posted by rh77 View Post
Some warm-up a car from a cold start by driving a little, shutting it down to coast, starting it, repeat, etc.
I usually wait a couple blocks, but yah. There's some good CODFISH to be had around the house. I don't consider it a "cold start" since the bearings are lubed and the oil hasn't run back into the crankcase, but only testing or a rash of dramitic failures will tell

Quote:
Originally Posted by rh77 View Post
...Long story short -- if you really want to get to know your car for better FE -- find a shop manual. I never dreamed an automatic transmission was so complicated, for example, and what conditions need to be met for lockup.
RH77
The funny thing is, the hybrid and automatics are harder to control
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Old 02-06-2007, 10:06 AM   #6
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Case and point, I was driving the sw2 automatic, in order to keep it in top gear while climbing a hill I had to back off the throttle as I climbed, whereas I could have held it steady or even accelerated (which is waht I really wanted to do) in a stick. Of course bump starts are gone and the thing revs up pretty bad on electric start.

I'm REALLY tempted to find a >=97 s series parts car with a significantly fresher motor and manual trans and just get the conversion over with.
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