Power Mode anecdote

[PeteJE]

I have mentioned on some of the MPG threads that I live up in the foothills - a 1 -2 mile slow, steady climb up back home in a 30 mph zone. I am always in normal or eco mode and I take a good hit to mpg getting back up home - I usually need to go into the pwr area on the HSI just to accelerate reasonably and hold some speed on segments of this leg. I would rarely get over 25 mph.

I have been trying different things - being very ginger on the pedal and very slow; driving normally; pushing it, I usually see the same half a mile drop or so on the mpg (given a trip meter at ~ 200 miles).

Last night I used power mode. I accelerated more briskly up to speed and held speed with more power in this mode. Obviously more rpms and engine this way. The surprise - I lost the least in my average mpg and it seemed to be a more economical way to go up. Maybe because of less time, maybe because of more efficient spending of power? I will be trying more experiments trying to get specific about if this is really better, but I was surprised.

[hobbit]

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*

[jburns]

Originally Posted by PeteJE

I have mentioned on some of the MPG threads that I live up in the foothills - a 1 -2 mile slow, steady climb up back home in a 30 mph zone. I am always in normal or eco mode and I take a good hit to mpg getting back up home - I usually need to go into the pwr area on the HSI just to accelerate reasonably and hold some speed on segments of this leg. I would rarely get over 25 mph.

I have been trying different things - being very ginger on the pedal and very slow; driving normally; pushing it, I usually see the same half a mile drop or so on the mpg (given a trip meter at ~ 200 miles).

Last night I used power mode. I accelerated more briskly up to speed and held speed with more power in this mode. Obviously more rpms and engine this way. The surprise - I lost the least in my average mpg and it seemed to be a more economical way to go up. Maybe because of less time, maybe because of more efficient spending of power? I will be trying more experiments trying to get specific about if this is really better, but I was surprised.

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.

[PeteJE]

Originally Posted by hobbit

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*

Ahh yes, of course. If it is just a log curve changing on the pedal with the different modes, then pushing for more power in normal or eco should be the same.

I want to pay more attention to this... does the HSI scale change with the mode change?

I could swear, top of the HSI (just before pwr) yielded more rpm sound and feel in power mode than the same place on the HSI in normal or eco mode. It could just be the different throttle response causing me to generalize more effects than were really there.

[bwilson4web]

Originally Posted by PeteJE

I have mentioned on some of the MPG threads that I live up in the foothills - a 1 -2 mile slow, steady climb up back home in a 30 mph zone. I am always in normal or eco mode and I take a good hit to mpg getting back up home - I usually need to go into the pwr area on the HSI just to accelerate reasonably and hold some speed on segments of this leg. I would rarely get over 25 mph.

I have been trying different things - being very ginger on the pedal and very slow; driving normally; pushing it, I usually see the same half a mile drop or so on the mpg (given a trip meter at ~ 200 miles).

Last night I used power mode. I accelerated more briskly up to speed and held speed with more power in this mode. Obviously more rpms and engine this way. The surprise - I lost the least in my average mpg and it seemed to be a more economical way to go up. Maybe because of less time, maybe because of more efficient spending of power? I will be trying more experiments trying to get specific about if this is really better, but I was surprised.

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

[angelrob]

Originally Posted by bwilson4web

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

...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.

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!

[cpatch]

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.

[bwilson4web]

Originally Posted by cpatch

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

[ken1784]

Originally Posted by PeteJE

Maybe because of less time, maybe because of more efficient spending of power?

My bet is "because of more efficient spending of power".
2010 Prius 2ZR-FXE engine efficiency map

Ken@Japan

[MarvHein]

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?