Pulse, Glide, Warp...??

Hi Chris,

Your basic summary of P&G seems right. Others have more experience with this, but I think that the reason you are sometimes not able to get into glide is due to the car warming up OR the battery running too low. While the car warms up, the engine must run more to get up to temperature, and may not shut off when you want it to. It might take five minutes or so before P&G really works. I also think its possible for the engine to keep running if the battery has gone down significantly, but I could be wrong about this.

Warp stealth does refer to over 42 mph. At this point, the engine will keep spinning, but you can get to a point where you run on electric only. I personally haven't gotten the hang of this, and prefer cruise control at highway speeds, so I can keep my eyes on the road.

 

One thing that will help is to get a grasp of the The Five Stages of Prius Hybrid Operation. That will explain why you can glide at some times and not at other times.

 

I think I'm just in the stage of understanding immediately after the one you are at. While others are more qualified and experienced to explain the details of all these approaches, I think that a commonly overlooked issue is highway performance. This is probably because the EPA mpg figures are lower for the highway where most people simply use cruise control.

Well I'm beginning to learn when to use the "only yellow arrow" condition for highest mpg in parkway speeds.

Also how to accelerate at the most efficient range of the ICE something commonly overlooked because of Toyota's inexplicable blunder of omitting an ICE rpm monitoring system in standard instrumentation.

How to keep the battery charged to 6-7 bars as much as possible.

All these 3 approaches have to be adjusted and fine tuned for each commute, trip, traffic conditions, traffic light timing and terrain.

Coming to work today I got +69 mpg over 8.5 miles and going back I'm hoping for something like 45-47 but that's probably wishful thinking. Currently showing 55.7mpg after 144 miles.

 

Unless I'm misunderstanding what I'm seeing happen, personal esperience indicates that:

1) The higher the charge on the battery, the easier it is to get into a glide. If I've just come down a long hill and I've got green bars, I can get into glide without even looking at the MFD. If the bars drop below the half mark on the MFD, I struggle to get into glide sometimes. The few times I've ended up near the bottom of the SOC guage, I haven't been able to induce glide at all.

2) During some of the earlier "warm up" stages, it can be impossible to get into a "glide" state unless you have an EV mod installed.

3) It isn't necessary to let up all the way on the pedal and re-press it to engage glide. At times when I've been backing slowly off I've seen the glide initiate. It seems easier to find glide and get there quickly by backing off entirely and re-pressing, but I suspect that with practice it should be possible to go directly from accelerating to glide by backing off the pedal just the right amount to go straight to glide. This would avoid a small amount of loss of momentum from the regen mode when you let off the pedal completely.

4) As has been explained here already a bit, above 41(?) mph the ICE spins even if it isn't providing power. This uses up some small amount of energy to overcome inertia and internal friction. It is possible to get into a state where the car is not using the ICE for power above this speed, essentially running on electric (or coasting with only momentum used), and this mode is generaly referd to as "warp stealth" to differentiate it from "EV" and "glide" because of the additional energy used up by the spinning ICE. If you have no energy transfer indicated on the MFD while above this speed it is sometimes refered to as "warp glide" to differentiate it from energy from the battery.

 

<div class='quotetop'>QUOTE(ChristoB @ Jun 19 2007, 10:25 PM) [snapback]464604[/snapback]</div>

You're absolutely correct about the pulse and glide.
Anyway, the good reference is...
http://hybridcars.about.com/od/ownership/a/pulseandglide.htm

However, I would like to suggest that you can find your own pulse and glide technique.
My suggestion is you don't have to keep the no arrow gliding. You can do little discharge(yellow arrow) coasting to minimize the pulse part of distance, then you'll see very good FE when the average speed is 20 to 30 mph.
Of course, it is not a good idea to use too much battery power.

I believe they depend on battery SOC level.
If the SOC is low, Prius'll try to charge the battery, then you'll see the ICE is coming ON soon.
If the SOC is high enough, Prius'll try to use the battery power.

Yes, the "warp stealth" is for above 42 mph where the ICE is always spinning.
As you observe, "warp stealth" is very difficult to achieve and very limited FE gain.
My suggestion is to use CC on the highway and be relax.
Then, you decide the target speed. Please note that slower speed results better FE.
And, set your speed one or two mph slower than target when you're going uphill, or set your speed one or two mph higher when you're going downhill.

Ken@Japan

 

<div class='quotetop'>QUOTE(efusco @ Jun 19 2007, 10:18 AM) [snapback]464664[/snapback]</div>

I'll accept that. Currently my only indication of "glide" is: no arrows on the MFD. If that is not an accurate indication of glide, then my impression of how easy glide is or isn't at various times is obviously flawed. I assume that a ScanGuage would help in this matter? I've been considering the purchase, but need to save up enough hobby cash to pay for it first.

<div class='quotetop'>QUOTE(efusco @ Jun 19 2007, 10:18 AM) [snapback]464664[/snapback]</div>

Easy to get in vs. easy to stay in. Opposite sides of the same coin to me. I suppose I should have phrased it as "difficult to maintain a consistant glide." The point being that if I don't keep my attention on the MFD, I end up outside of the glide without realizing it, whereas when the SOC is full, I fond that I can pop right into a "no arrows on the MFD" state and keep it there with little effort at all.

<div class='quotetop'>QUOTE(efusco @ Jun 19 2007, 10:18 AM) [snapback]464664[/snapback]</div>

This is probably due to my error in considering "glide" to mean no arrows on the MFD. For the vast majority of Prius drivers (all those who haven't bought some sort of tach indicator), this is probably the closest they can get to an indication that they are in or near a "glide" state.

I'm quite curious as to how much efficiency is gained by being in a true "glide" state vs. being in a "no arrows on the MFD" state. For a full tank of p&g are we talking about a 30% increase in mpg? 10%? 5%? 1%? fractions of a %?

 

I believe in simplification.
For me, when I've got the consumption screen (with the bar graph) on, I just try for as many minutes as possible with the current usage bar to be totally green.
I can do this most of the time during the city driving portion of my commute, and occasionally on the highway, as well, depending on conditions (the highway is mostly "flattish").

 

I dont have a scan guage, but one way you can tell the ICE is running is that your instant MPG will alot of times still say something like 78.6 MPG during a glide. I usually see this only while engine is warming up in the first few minutes of operation.