Making Arrows Vanish

[airportkid]

I've seen numerous posts referring to "coasting" or "gliding" with an arrowless energy display - but I either haven't figured out how to "feather" the throttle to attain this Zen like display or the software in a late '05 Prius no longer permits such a representation. If the wheels are turning, my Prius will show arrows, sometimes the whole quiver all at once. Which makes sense. If the wheels are turning, the energy is kinetic, and it's either going from the wheels into the battery, or the synergy drive is turning them. The only time, logically, that the arrows would be absent is when the wheels are stationary.

So is an arrowless display while in motion actually possible - or have I misunderstood all the posts?

Mark Baird
Alameda CA

[efusco]

It's possible, but takes time and practice.

Try this next time you're out and can mess around without risk to other traffic or pedestrians.

Once the car is nice and warmed up and you don't have the AC working too hard and you're sure the defrosters are off start a nice smooth moderate acceleration up to 39mph (no faster) on a flat stretch of road. Quickly lift your foot completely off the gas pedal for about 1/2 to 1 second so that only green arrows (regen) from wheel to battery show and the ICE shuts off (if the radio is off it will help you hear it, but you should be able to 'feel' it too).

Now, very carefully and slowly reapply pressure to the gas pedal until the green arrows disappear and hold that position. You shouldn't have much trouble with that. Getting a no arrows condition at any speed over 40mph is very very difficult...but even that can often be done with practice.

[andyprius]

Originally posted by airportkid@Jan 5 2006, 08:08 PM
I've seen numerous posts referring to "coasting" or "gliding" with an arrowless energy display - but I either haven't figured out how to "feather" the throttle to attain this Zen like display or the software in a late '05 Prius no longer permits such a representation.  If the wheels are turning, my Prius will show arrows, sometimes the whole quiver all at once.  Which makes sense.  If the wheels are turning, the energy is kinetic, and it's either going from the wheels into the battery, or the synergy drive is turning them.  The only time, logically, that the arrows would be absent is when the wheels are stationary.

So is an arrowless display while in motion actually possible - or have I misunderstood all the posts?

Mark Baird
Alameda CA

[snapback]184458[/snapback]

After the SOC is sufficient on the HV Battery you may let your foot off the accelerator and then very gently just touch the accelerator pedal until you get a no arrow condition. Simple right? However sufficient SOC is variable and generally requires at least 10-15 minutes warm-up. This no arrow or free wheeling so to speak will only occur with a green or purple battery state, signifying a proper state of charge. During a nice Sunday drive this is easy to obtain especially with nice downhill sections. If you bring the Prius up to a coast and then throw it into neutral you will duplicate the no arrow condition. In doing this, for some reason does not seem to appreciably add to MPG. I'm convinced its detrimental to MPG ( by coasting in neutral) Why this is so has not been addressed by our experts. The consensus is however that putting the car in neutral will not hurt it, niether will returning the car to drive.

[hdrygas]

Originally posted by airportkid@Jan 5 2006, 05:08 PM
I've seen numerous posts referring to "coasting" or "gliding" with an arrowless energy display - but I either haven't figured out how to "feather" the throttle to attain this Zen like display or the software in a late '05 Prius no longer permits such a representation.  If the wheels are turning, my Prius will show arrows, sometimes the whole quiver all at once.  Which makes sense.  If the wheels are turning, the energy is kinetic, and it's either going from the wheels into the battery, or the synergy drive is turning them.  The only time, logically, that the arrows would be absent is when the wheels are stationary.

So is an arrowless display while in motion actually possible - or have I misunderstood all the posts?

Mark Baird
Alameda CA

[snapback]184458[/snapback]

It is not easy. If it was everyone would pump their tires to 60 psi throw out the spare and rear seat and get > 100 mpg. First try this, after the car is warmed up (easy in your neck of the woods) hit the B mode. You will see no arrows. Go to drive. Accelerate to the speed limit or if you dare 3-5 over and take your foot off the gas. You get the green arrows. Let that go for 2-5 seconds. It needs a bit of time. Slowly and gently (you have a raw rotten egg between your foot and the accelerator if you crack that egg your car will be unusable for 5 years ). If you get yellow arrows to MG2 back off just a bit. No arrows you are gliding. The car must be warmed up to above 70 C. The next part is harder much harder. I am still working on this. When you accelerate press on the gas until there is power to the wheels from the ICE with or with out power from MG1 to MG2. Nothing to or from the battery. If you are getting flickers to and from the battery that is OK to start with. I try to stay away from sustained (several seconds) of battery to MG2 and am willing to accept some charging. Dead banding is really tough. Work on it. You can get a ScanGage or CAN View to help you get a handle on when the ICE is running and when the ICE is up to temperature. Fun, Fun, Fun.

[andyprius]

Originally posted by andyprius@Jan 5 2006, 09:45 PM
After the SOC is sufficient on the HV Battery you may let your foot off the accelerator and then very gently just touch the accelerator pedal until you get a no arrow condition. Simple right? However sufficient SOC is variable and generally requires at least 10-15 minutes warm-up. This no arrow or free wheeling so to speak will only occur with a green or purple battery state, signifying a proper state of charge. During a nice Sunday drive this is easy to obtain especially with nice downhill sections. If you bring the Prius up to a coast and then throw it into neutral you will duplicate the no arrow condition. In doing this, for some reason does not seem to appreciably add to MPG. I'm convinced its detrimental to MPG ( by coasting in neutral) Why this is so has not been addressed by our experts. The consensus is however that putting the car in neutral will not hurt it, niether will returning the car to drive.

[snapback]184532[/snapback]

The Dr beat me to it, thanks Evan

[hdrygas]

Every one is chiming in. The slight down hill is a good addition to start with.

[andyprius]

Originally posted by hdrygas@Jan 5 2006, 09:53 PM
Every one is chiming in.  The slight down hill is a good addition to start with.

[snapback]184540[/snapback]

But not found in Alameda!

[Salsawonder]

You live in SF so it will be difficult to get "no arrows" in the city. Going downhill will still get you recharge arrows. If there is a more level area that you drive try it there. You really have to get a light foot and even then the arrows will not last for more than 20-30 seconds at a time (unless you are on some very level but very slightly declining road (which does not exist in your area!)

[tripp]

I would also say that you're probably going to find "deadbanding" to be difficult there as well. Deadbanding is pretty easy to achieve on flat ground as long as you don't try to accelerate to briskly. Frankly I wonder how effective it really is, particularly if you're going to encounter situations where regenerative braking can help replenish the HV energy you consume by demanding a little more power from the car. It seems to me that if deadbanding is going to get you up to cruising speed at a somewhat slower pace than moderate acceleration w/battery assistance then overall you're not going to see an increase in MPG. In fact, if the discrepancy is big enough, you'll see a drop in MPG. Not that deadbanding is to be avoided at all costs either. There are times when it makes sense.

[driveprius]

Originally posted by airportkid@Jan 5 2006, 09:08 PM
I've seen numerous posts referring to "coasting" or "gliding" with an arrowless energy display - but I either haven't figured out how to "feather" the throttle to attain this Zen like display or the software in a late '05 Prius no longer permits such a representation.  If the wheels are turning, my Prius will show arrows, sometimes the whole quiver all at once.  Which makes sense.  If the wheels are turning, the energy is kinetic, and it's either going from the wheels into the battery, or the synergy drive is turning them.  The only time, logically, that the arrows would be absent is when the wheels are stationary.

So is an arrowless display while in motion actually possible - or have I misunderstood all the posts?

Mark Baird
Alameda CA

[snapback]184458[/snapback]

The easiest way to experience the no arrow state is to:

1) Make sure your engine is fully warmed up. After 10 minutes of driving this should be enough.
2) Make sure you have no red bars on your battery.
3) Find an area where the speed limit is 45 mph or less and your in a slight downhill. The steeper the downhill the easier.
4) Get your speed so that it is no more than 40 mph and it is safe to do so.
5) Lift off the gas and allow your car to coast with green arrows going to the battery. This is coasting like a conventional car as your Prius will tend to slow down with engine braking.
6) Now press the gas down just slightly until you see the green arrows go away.
7) You should either see no arrows or possibly a momentary appearance of yellow arrows from the battery to the electric motor.
8) If you see the yellow arrows, wait about 2 seconds to see if they go away. If not just back off the gas pedal just enough to make the yellow arrows go away.

The no arrow state is the tiny sweet spot in between having the green arrows appear and the yellow arrows appear. When you drive 40 mph on level road or downhill it's easiest to achieve.