Power Mode anecdote

I bet if you just left it in normal mode or even ECO and just
pushed harder, you'd see the exact same effect. Try matching
what you're doing to a particular reading on the HSI, and see
how that affects your observations...
.
_H*

 

I am seeing evidence that power mode might give a bit better mileage than eco mode when using cruise control while driving over rolling hills. When I hit a significant hill on cruise in eco mode the car losses between 2 and 3 miles-per-hour before increases the throttle enough to steady the speed. It then has to try and regain the lost speed while going up the hill and you can hear the engine quite clearly as it increases RPMs.

Approaching the same hill with cruise and power mode the car never losses more than 1 mile-per-hour. It actually losses less because sometimes the speedometer doesn't change. Since the car now does not have to make up lost speed on the hill the engine never becomes audible in the cabin. The result is steadier speed and quieter overall ride and hopefully even a bit better mileage.

 

Cool! We need additional data to complement this hill climb data:


For protocol, please consider doing the following:

• same start and stop place - key to reproducible results
• cruise control speed control - reach the target speed before the entry point and reset the trip meter at the start and record the trip meter at the stop point
• consider going 'downgrade' first so the climb speed can be set on a flat before the upgrade. Accelerating up a grade is mileage death
• consider doing a 20-30 minute 'warm-up' drive before running the benchmarks - there is an engine warm-up cost and it can reduce the metric
• GPS track and/or other slope track - I've used topology maps, GPS track and other means to understand the slope and altitude change

My nearest 'mountain' has only a 525 ft. rise on a 6% grade. What we don't have are other reports or data for different grades and altitudes. What we want to find is the optimum, steady-state climb speed that converts fuel to potential energy. For example, this is my earliest hill climb chart:



Thanks,
Bob Wilson

 

I am beginning to think that if I knew how much of a geek-car this can be, I'd have traded the Jeep YEARS ago!

 

I get absolutely no power out of the ECO zone on hills...I have to go into the power zone in order to just maintain speed.

 

You may notice there are three characters under the 'red zone:'

• P
• W
• R

You could hold the power setting over each of the characters and document the time to climb. Knowing the weight and height and time, we can calculate the power setting of each character.

Bob Wilson

 

My bet is "because of more efficient spending of power".
http://priuschat.com/forums/gen-iii...2010-prius-2zr-fxe-engine-efficiency-map.html

Ken@Japan

 

There has been a suggestion that one could achieve PWR results in ECO by using more foot. A counter would be that one can achieve the same results in PWR as in ECO by using less foot.

I don't have any fancy charts or graphs, nor do I want to try to make any, but this is what I've observed in my first month.

I tried my darnedest to use ECO mode to break 60 mpg. It's easy to do on a single leg, but I've not been able to maintain it for a tankful. And I have to drive pretty scarily slow to do it.

Because Las Vegas is in a valley, there are more hills than some might think, especially if you live on the outskirts and work downtown. I have a 16 mile commute mostly downhill, which is great, but a 16-mile commute mostly uphill, which stinks. Then there's the highway speeds which suddenly become stop-and-go, etc., etc., etc.

It's only been a couple of tanks, but I've been noticing about an extra 2 mpg (56 vs. 54) using PWR mode all the time instead of ECO. (It takes a light foot to do this because the reported stickiness between the electric and ICE zones on the HSI is diminished or gone.)

Still, it seems getting up to speed quicker allows me to glide sooner, maybe because no one is right on my rear bumper. And because I have more momentum when I get up to speed, I can glide a bit longer. In short, I can drive more like the rest of the maniacs on the road and pick up some fuel economy at the same time.

Do I spend more gas accelerating with a short pulse in PWR vs. a longer pulse in ECO? It seems maybe not.

Since downhill is easy in both modes and shows similar mpg, perhaps you're right and the new-found advantage is on the uphill portions of the trip.

(For any other non-turtles, I posted my general approach to PWR driving in the "How Do You Do It?" thread earlier today.)

Curious to see how others are using PWR mode.

Is Normal somewhere in between?

 

I too have seen exactly this -- you can pulse faster in PWR mode (well into the RED PWR zone at the end of HSI display) and then glide longer for better mileage.

In my daily commute, I reset trip-B for each leg of my 53km commute (it usually takes about 60 - 75 minutes give or take during rush hour). With PWR mode, I got a couple of my best mpg readings (3.0L/100km or 77 mpg US). The car reads about 10% high, so I don't really get 77 mpg - but 69 mpg is not too shabby.

Unfortunately PWR mode is really seductive, so you have to be very careful not to misuse it or you'll end up with worse mileage. For this reason I tend to stay in ECO mode most of the time and only use PWR mode when I feel it really need it (like merging into heavy traffic).

People say that you can do the same thing in normal mode and ECO mode by pressing the pedal further down, but based on my own experience, I tend not to be convinced.

 

Ditto.

 

My son would agree with your seductive comment. This approach is not suggested for teenage drivers. He's killed some mpg that have taken me a day to recover.

My only problem with staying in ECO mode and switching into PWR as needed was having my simple brain sort out which mode I was in when an unexpected traffic situation presented itself. Sometimes I'd hit the pedal thinking I was in ECO when I was in PWR car or think I had extra power only to find I didn't ballchain. If they'd put the PWR switch on the wheel, it'd be easier to switch in and out.

Maybe normal is really the best of both worlds, except for the name. Since there is no "normal" switch, I guess we can call it anything we want...

Using normal will be my next tank. I haven't been there yet.

 

Why not split the difference, and use NORMAL mode?
.
The "getting up to speed faster" argument is specious, because
if you're talking about MILES per GALLON, time drops out of
the equations that lead up to it. And if you've kept your
instantaneous MPG lower over a given *distance*, guess what
happens to your average??
.
And since HORSEPOWER is all about how fast you lift the weight,
at constant power output you either climb at a given rate or
accelerate on the flat at a given rate or some nominal mix of
both, but not BOTH without applying a lot more power. No harm
in grinding up hills a bit slower, since if our overpowered
society ever wises up and learns how to terrain-drive with
smaller engines, they'll get used to it. Start now, it's
more efficient by far.
.
The sweet spot is between not pushing too hard and not letting
it loaf, and I'm still looking for confirmation on whereabouts
that is on the HSI. The eco/pwr distraction doesn't matter
for that, y'know.
.
_H*

 

I was under the impression that the ECO mode somehow changed the inner workings of the ICE, different timing, valving and throttle positions or whatchamajig. My feeling is that the ECO mode does that all for us instead of regulating with our foot. Although it appears that some folks on here have managed to become super sensitive to driving techniques that they have out performed the system. The majority of new hybrid drivers will benefit from having the car make the decisions on performance by using ECO mode.

 

For me, NORMAL mode and ECO mode feel similar enough that I view them as almost interchangeable. I've used ECO mode most of the time since I believe that it would also deliver an A/C benefit (although this year has been cool enough that I haven't needed to use the A/C much). So I would have no trouble believing that you could equate ECO mode with NORMAL mode just by pushing the pedal down a bit further.

But there's something different about PWR mode. A few times, I've been sitting at an intersection and decided to make a quick left turn with traffic coming toward me in the opposing lane. While in NORMAL/ECO mode, I've had the car bog just enough to cause me a bit of concern. I made the same turn in PWR mode and I squeaked the tires while blasting through the intersection. I had the pedal floored to clear the intersection ASAP in both cases.

Yeah, I know that this is a very legit argument and I can't explain it. But my mileage was still exceptionally good on two of the three times that I tried pulsing heavily into the HSI PWR red region. I was going with heavy traffic that was naturally pulsing; maybe hard pulsing in PWR mode somehow better matched the traffic patterns and I was somehow subconsciously using this to my advantage?

This sounds reasonable, but it's a bit demoralizing when you get passed by that 10-ton truck that's been following you in the right-hand lane for the last three miles -- especially when he moves back into your lane right in front of you after he passes.

Perhaps, but I'm not quite ready to accept that yet.

 

Me either. Someone posted somewhere that the ECO and PWR switches are actually connected to different parts of the system. PWR must bring some other factors into play that some may not have explored due to the implications of its name.

My results are definitely better in PWR. I tried really hard in ECO and couldn't get there consistently.

I know it doesn't "feel" right and I'm not saying some people can't do better in EVO mode in their particular environment. Many clearly do. I'm using A/C constantly in 105 degree weather and fighting stop-and-go, 70 mph highway speeds, 45-50 mph side street traffic and hills. When I can creep, I do. Most times I can't.

For me and my mix of conditions, PWR really seems to be advantageous, even if turning it on turns off the little green leaf on the dash.

 

I did say I was going to try NORMAL next...

It's not the getting up to speed faster part that makes a difference. I'm suggesting that I can then subsequently drive efficiently longer BECAUSE I got up to speed faster. It's a suggestion that doesn't fit a rural or small town environment, but might help others in metropolitan settings.

It's possible all the modes do is control the sensitivity of the throttle. If that is true, your premise that targeting the same pulse glide zones on the HSI is right on. It doesn't really matter which mode we use as long as we drive efficiently. People with light feet can use PWR and people with heavy feet can use ECO.

But I'm using the same HSI zones in ECO and PWR modes and getting different results. What I think we're suggesting is that PWR may use the ICE and electrics differently than ECO. These modes are new to the 2010 and may or may not be well understood. They're not well understood by me, or I wouldn't be busy experimenting.

If they are indeed different, there may be a way to use those differences to our advantage in certain environments. Hilly territory seems to be a common theme in this particular thread.

For me, I'm considering moving my ECO switch cap to the PWR location. (After I try NORMAL.)

 

Sorry- blunt question: has anybody simply tried to drive reasonably in "normal" mode and see what happens?
In normal cars, accelerating 3/4 of total, shifting gears rapidly and then keeping constant speed with as little as gas possible to keep momentum is the best way to reduce fuel consumption. Braking when not necessary and accelerating when seeing a red-light in front of you, does not help.

Because the Prius is all geared toward fuel consumption, wouldn't be simple to just:
- use normal and drive sensibly (as per above) and see what happens
- use ECO when cruising around or "having time" to reach a destination, or in slow city traffic/stop&go on highways
- use PWR when "in a hurry" or simply want to have some driving fun on winding roads, forgetting about MPG?
and let the computer do its job?
Shifting between modes depending on traffic is a bit nonsense to me (and honestly speaking stressful). That is not the purpose of the buttons IMHO. It is just a way for us to say "Prius, I will be wanting to drive like this (ECO/PWR/Normal) - do your best".
Aren't Prius users freaking a bit too much on the fuel consumption?

I often got the best MPG on my current Polo Diesel (Prius arriving end of month!) in fluid city traffic, when *not* looking at the MPG indicator, and instead looking at traffic lights and traffic ahead behaviour, breaking as little as possible or using engine break force (0L/100km) to break, and reaching cruising speed as fast as possible with 3/4 foot on the pedal.

Also, since I have a manual gearshift, I try to keep the engine in its most efficient rpms by shifting gears (max torque with lowest fuel consumption).
I expect all this to happen automatically on the Prius, regardless on what I do on the gas pedal....!

It is very difficult to speak about how much me, you or somebody else consumes on any given car - different traffic conditions, usage, gas pedal behaviour, etc. all affect MPGs. I would just drive the Prius in "normal" (or as per above) and just enjoy the ride.

I mean, worst case you are still (especially in the US) still consuming, what?, 1/3, 1/2 less than any other car on the market...

 

I'm having similar thoughts...I can barely get up some of the on ramps to the freeway here in LA if I don't go into the power section of the HSI. I deal with a lot of steep inclines and if I stay in the Eco zone I feel like I'm just using tons of gas because it takes me 2 minutes to get up to speed (exaggerating, but it feels like it takes forever). I'm not getting great mileage anyway, though, so maybe I'm just dumb or my car is a lemon...