With so much talk and controversy on very recent threads about forced auto stop (FAS)/reboot from several members, I decided to try it out for myself for the first time last night. My first two FASs were performed through a wide, level, mostly corporate office/industrial arterial with ~50MPH speed limit and lots of spacing between traffic lights. I'll admit I was pretty nervous, but I know the streets well and felt very comfortable utilizing the FAS technique at a time when no one else seemed to be on the road.

I'm not goiing to debate the safety/car control/tranny issues that have already been brought up, but to sum it up, I think its an amazing technique when used in a situation where you feel confident and in control. It was an eerie sensation when I shut my car down while coasting in Neutral at 40MPH and restarting the accessories, but once I engaged the FAS, the HCH felt like it could coast for a quite some time and the instantaneous MPG meter was through the roof. When it was time to restart the HCH, the car started with no problem, and I just made sure the RPMs settled ~1,000 (at roughly 30MPH, 10MPH less than when I started) before I put the car back into Drive. I didn't notice any hesitation from the tranny. I will never do a FAS during daylight hours, anytime before 10PM, or in a residential area, just based on my comfort level, but the few nights per month that I work overtime past 11PM, I now know I have another FE technique to utilize on the empty streets by my office. I figure a handful of FASs per month should be "mild" enough for the longevity of my CVT.

So to the experienced FASers, am I doing the FAS/reboot correctly? Any suggestions?

 

I know it's WAY too late to suggest a better name for the technique, but I would call it a FES Forced Engine Stop since there's nothing automatic about it... if it restarted by itself, then yes FAS, but it's a manual engine shutdown, simulating the function of auto stop.

 

FES is a lot better than FAS, but let's not change at this point. It's taken me a few weeks just to understand what a FAS is. Hypermilers, how long do your FAS's usually last? Is it worth it to do an FAS for under 30 seconds? Sometimes when I turn the engine off and turn the controls back on, my car goes right back into gear. Do you usually wait more than a second or two to turn the controls back on?

 

Good, safe job Eskrimast1!

BBB,
My FAS last for several minutes each all the way to zero seconds.
If I'm in a creepy crawler traffic jam I'll often start her up for a nudge, then shut her down again and slowly roll a couple of hundred feet.
Like in the video I made.
Typically I'll get off the gas and wait for the RPM's to drop below 1k, switch it to off for 1-2 seconds then reboot.

Speaking of the video, you'll notice about 14 miles of almost constant staircased uphills. These can really hold the MPG down if not extremely careful.

But on the way home at 2:45AM they are a true blessing.
Completely abandoned except for the occasional critter wandering about,
I FAS down the gentle hills:

The first FAS is for ~1/2 mile to a stoplight. Speed is about 35 and I can see the light far off and since it is on a timer, I can adjust myself and make it green.
(This is the first light I turn Right at in my video)

Next one is approaching a light that is always red that I would usually go straight through without turning.
1/2 mile away I'll FAS @ 45MPH. As I approach the light I'm going about 20MPH.
Still in FAS I'll hang a right (Legal), travel about 150 feet and turn Left onto a short road, still in FAS. Now since the road is a slight downhill I'm slowly gaining speed. As I approach the original road I was on, seeing zero cars on the road I'll restart, put in gear, merge and be on my way.
Total FAS is about 2/3 mile.

Next one might happen up to a light that us not predictable, not timable.
If I'm approaching it and caught off gaurd, I'll FAS up to it.
(This is the 1st ot two lights of the traffic jam in my video)

About 1/2 mile past the light I'll be going 35-40MPH and FAS ~1/4mile to the top of a long, gentle 1/2 mile hill. I'll roll down to the bottom picking up speed to about 45-50MPH and continue in FAS another 1/2 mile or so until my speed is 40MPH.

Then I restart and set my FCD to 40MPG to overcome a couple of slight hills, and to gain speed for the next FAS, which is a long one.

At about 45MPH I'll shut her down and roll about 2 miles down a gentle hill.
At the end I'm going about 35MPH.
There is a short but steep hill to climb about a mile ahead so I'll restart and again set the MPG to 40 with Assist on and off.

I'll reach the base of the hill going about 50MPH, shut off Assist if it is on and hold the FCD on 44-46MPH and ride the hill up to the top. At that time I'm going about 35-40MPH.

Time for another long reboot.
Another FAS and I'll gently roll down the other side of that hill, go about a mile and up another hill.
Since I'm still in FAS I crest that 1/4 mile hill going 25-30MPH. Rolling down that hill another 1/2 mile and up another hill then I'll start her back up.

Again targeting 40-48MPG I'll gain speed back down the hill to about 50 at the basin, then begin climbing a taller one beyond.

At the top of that hill I'm going about 40MPH and is another long FAS.
I'll reboot and roll up & down gently rolling hills about a mile to a light.
(This is the 2nd light in my video)

Now this light is situated on the other side of a curb.
Acutal sight of the light is about 1/8 mile away.
You have to understand that at 3:00AM there is alot of humid mist in the air.
I can usually see what color the light is up to ~1/2 mile away by the color of the mist being carried by that light.
When it turns green I have a good 2 minutes to make it.
If it's green mist I'll restart and get to about 40MPG touching Assist and 75% catch it green.
If I see red mist, I remain in FAS until I stop.

After the light is a tall, short hill.
At the top of the hill I'll do another FAS for about 1/2 mile.

Then I restart @ 40MPH and gain speed going downhill in the 44-48MPH range to the base of the large hills in the first part of my video. My target speed at the base of these uphills is about 55.

At the top of those hills I'm going about 30MPH.
Time for another reboot, about 1/2 mile to the first light in my video.

I restart at the light and turn Right, climb a series of small hills and reboot for another long run (More than 2 miles) and make a hard turn. Still in FAS I'll roll a distance to my subdivision.

Since it's all uphill to my home I'll restart and immediately get to and hold it at exactly 20MPG to a certain landmark (Someone's mailbox) and another FAS to the house. 20MPG to that specific mailbox was found by experimentation.

This carries me through my fence, now at "pushing" speed where I roll into my parking area.


Note that while I can't do most of those FAS's during the day, yes I can and do some of them safely.

If you're a newbee or otherwise don't know about the video I made on my way to work last Spring, it can be found here:
https://www.greenhybrid.com/discuss/...7&postcount=32

Thanks for reading this novel!

 

Hi Schwa:

___The FAS was developed by Honda IMA owners mainly for Honda IMA owners and it does exactly what it describes. A std. AS kicks in below 20 mph. You can perform a FAS at any speed higher by forcing it. In a non-hybrid, you have to Force an Autostop at any speed. It doesn’t just disengage the tranny and shut the ICE down just as a reboot doesn’t start the ICE back up and place her back in gear. In your HSD equipped hybrid, dropping the stick to neutral should shut down the ICE for a FAS as long as your SoC is not playing in the pink.

___Eskrimast1, it sounds like you nailed it. To improve upon the method you used (it sounds like you were actually P&G’ing in a 30 - 40 mph range?), do you have a slow down around your office complex anywhere? A stop sign, traffic light, cross streets with no signs that you are/will/always slow way down or come to a complete stop at? This is where the FAS can really work its magic. Instead of a repetitive 30 - 40 mph FAS which is a P&G, you simply FAS from whatever speed you are at all the way to a stop! There are various relatively flat or slight downhill grades where a FAS can carry you for 1, 2, 3, and even 4 miles from what I have read in various parts of the country. I have a 2 mile stretch out on I-55 with a nice 100 - 150’ drop over a 2 mile distance that works magic because traffic is always tied up at the bottom of that thing and a FAS from 60 usually gets me right into the thick of it at < 20 mph. Most of my own FAS’s are a ½ mile or less and are definitely not all from 60 + mph. Driving around a Mall’s Circle drive for example is good for a 30 to 0 mph FAS if you are going to park in the completely clear outside edges of a particular stores lot as you should. There are a number of places this works but you must take special care of the traffic all-around for safety’s sake above any and all other considerations. It sounds as if you do and that is the most important tool of all … I am glad to hear you have another tool in your toolbox as it is truly a tool that all cars should be able to perform today. This includes both HSD and IMA equipped ones without all the gyrations! They will soon enough but Honda just doesn’t get it yet and Toyota has to work on MGSet protection to take it all the way up and all the way down … Well, maybe the 06 Honda Civic got it but we don’t know how IMA propulsion after ICE S/D is going to work in it just yet?

___Good Luck

___Wayne R. Gerdes
___Waynegerdes@earthlink.net

 

Xcel, my intended FAS turned into a P&G because the usual red light two miles away from the office turned green as I was approaching the intersection. So I had to restart and continue through the intersection. My original intention was to do what you mentioned and glide to a stop which as I understand it would have constituted a true FAS. Now I know the true difference between P&G and FAS.

I was driving through Laguna Beach last night around 10PM and although I didn't pull a P&G (due to 3 other people in the car), I was very tempted to. There are long stretches of ~2-3 miles along Pacific Coast Highway (3 wide lanes in each direction) where the grade is just gradual enough to keep the P&G going at a good 40-50MPH without losing momentum for a long time.

Have any of you hypermilers freaked out passengers with P&G/FAS techniques?

 

Heck Yeah!

Daddy turn the car back ON!!! No honey, I'm saving gas. DADDY TURN THE CAR BACK ON NOW! Ok honey bunny.

 

Hi Eskrimast1:

___You definitely know what you are talking about!

___The next time you have 3 + in the car and your current tank is relatively fresh and sitting at lets say, 53 mpg, perform a FAS on that gradual down slope. If one of your passengers ask what you are doing, you point to the current FE average of 53, the pegged instantaneous at 120 mpg, and tell them to watch your averaging display climb. Better yet, reset Trip B about 2 miles before so you are sitting in the low to mid 50’s and watch the on their faces when you finish off at 90 to 110 mpg!

You and 3 Friends in the car heading out for Pizza - $25.00
All 3 friends’ faces when they see you just received > 95 mpg over the last 5 miles …

___Yea, you got it

___As an edit, not all FAS’s have to end up at a stop but a P&G is a repetitive FAS that is usually kept into a much tighter and repetitive band. Both are fantastic ways to shoot your FE through the roof however and another set of tool(s) to use when and where appropriate as you have already experienced.

___Good Luck

___Wayne R. Gerdes
___Waynegerdes@earthlink.net

 

Why not just shift to neutral (leave motor running) and save rpms from that? No you don't get all the savings in gas but the real time mpg will also be pegged to max. Plus you have all other system working on your car... such as brakes and ABS.

 

What you are saying does work and is a great option if you are not comfortable with FAS.

ABS does work during a FAS. Guess how I know that!

Power brakes work, but only for so long. You do gotta be careful here. The brakes do take quite a bit of effort to work manually once the power assist wears off.

Power steering cuts off for just a couple seconds but it comes back since it is electric.

A FAS uses less gas (none) than coasting in neutral which is why some of us extream hypermilers use it. It is a bit dangerous so please be careful it you do decide to use it.

It is not a good idea to (IMO) to FAS in heavy traffic.