Real World MPG for our 2010 Prius. After 2,173.9

[a priori]

I mean no offense to some of the other folks who've provided earlier answers to the inquiry about a definition for pulse-and-glide, but Bob's succinct answer provides the guts of the response about what it is. How to do it is another story.

Pulse-and-glide really is not a valuable tool on the highway, and the return is difficult to find. In around-town driving, though, P&G is a fabulous tool for fuel economy.

I would suggest you keep these things in mind:

1. Momentum is the key; allow the car's weight to help you maintain current velocity.
2. Use brakes sparingly.
3. Learn how to truly "glide" in your car -- no acceleration, no braking, no coasting. The glide is that state when no power is applied to drive the car and no regeneration is occuring.
4. An even acceleration is best; try to achieve the target speed sooner, rather than later, but it can be done efficiently. Using the HSI Screen (Hybrid System Indicator), you should be able to accelerate to speed and still keep the "Eco" light on. (I'm usually pushing this so that the indicator is between 3/4 and 7/8 to the right and pretty close to the "Power" area.)
5. Don't just follow traffic patterns, but anticipate them and check far ahead to see if traffic is slowed or stopped or if there is a red light ahead. Most people waste huge amounts of gasoline by actually accelerating into red lights!

Bob's concise definition got close to the OP's request to get everything in twelve words. I'm hoping the above will provide a bit more additional assistance.

[bwilson4web]

First I want to thank you for posting the speeds as well as the MPG numbers. Too often we get just MPG without the speeds and that can be terribly misleading.

Originally Posted by toxicity

. . .
On the highway, I'll pulse up to 70 then glide down to 55-60.

It increases your fuel economy because you are moving along without consuming fuel.

In "steady state" or normal driving, where you hold the pedal down the whole time, you will probably end up with fuel economy numbers that look like 50 - 50 - 50 - 50 - 50.

With P&G, it will look like 99 - 99 - 99 - 99 - 35 - 38 - 40 - 45 etc.

If you peg the cruise control at 55mph in a Gen 2, you can get 55mpg. If you pulse and glide at the speeds I stated on the highway, you can get 60mpg or more. In the city, 75mpg or more (in the most ideal conditions, i.e. no traffic to encourage you to drive "normally".)
. . .

Is this table accurate for your vehicle?

min mph	max mph	avg mph	MPG	model	comment
55	55	55	55	NHW20	at 65 mph?
55	70	62	60	NHW20	Ok

.
The reason I ask is your vehicle performance seems a little different from results from other Prius. What I've found with my NHW11 and a report from an NHW20 owner and my wife's ZVW30:

min mph	max mph	avg mph	MPG	model
60	60	60	52	NHW11
65	65	65	52	NHW11
60	60	60	57	NHW20
65	65	65	53	NHW20
60	60	60	57	ZVW30
65	65	65	51	ZVW30

.
Source data for NHW20 and NHW11:


Source data for ZVW30:


What I found with my NHW11, a 2003 Prius, there was no significant change in MPG out to 65 mph. But once it exceeds 65 mph, the mileage falls off significantly. In contrast, the NHW20 user report and my wife's ZVW30 don't have a similar MPG plateau or fall off. They follow the expected aerodynamic drag curve.

Your data at 55 mph has me really scratching my head. It suggests that there may be a slight dip or at least a flattening of NHW20 performance under 60 mph. This plateau is evident in my NHW11 data. It would be interesting if you could try a run at 65 mph in your NHW20 or better still, at 62 mph to do a head-to-head comparison with your 55-70 PnG. This would quantify the PnG improvement.

Thanks,
Bob Wilson

[Bobsprius]

Great posts yet again by A64 and Bob!

I think it's a learning curve, watching the HSI as stated and the road ahead to anticipate. A perfect example, (So I know the car is capable) I drove a 11.9 mile trek yesterday after getting gas (reset Trip Meter) and this route has several traffic lights. I never got into the power range with accelerating, and anticipated the road ahead and the traffic lights. I was able to achieve 61.7 MPG on the route, be it only 11.9 Miles, but it's doable.

I see some posts where "I am not getting the best mileage and I am travelling at 75MPH" I don't think those are ideal conditions and your mileage tends to "suffer" a little in that case.

But if you mindful you will be able to get those high number that help round out when you are not able to given the road conditions and traffic etc.

Just thought I would share my experiences as well.

[lutece7]

it would seem that the traffic tickets one would accumulate in a year of driving pulse and glide would offset the fuel savings. Am I wrong?

[PriusRos]

Originally Posted by lutece7

I am finding that I really have to concentrate and be constantly mindful in order to get the 46mpg I am getting around town and on city toll roads. This is somewhat disappointing. I feel like I am hypermiling with my right foot, but not getting the hypermiling results. No regrets in acquiring this Prius, mind you. I just thought this car would get 50mpg without having to drive in a special way (very slow starts)

Is your route hilly? My area has a lot of hills and it also has a lot of lights, so it seems I am constantly having to start from a stop on a uphill slope. I try very hard (and have had a Gen II so am aware of P&G etc.) but only manage to achieve around 45mpg. If this applies to you, see Uphill vs. downhill makes the biggest difference. Also, how long are your daily commutes? If they are short (like mine), the car will not be operating at full efficiency.

[lutece7]

I don't commute. I office at home. so I drive to do things with friends, to go shopping, to run errands. when I have a photography job or go mountain biking, I still take my old Land Cruiser which gets 14 on the highway, 10 around town!

[toxicity]

Originally Posted by bwilson4web

First I want to thank you for posting the speeds as well as the MPG numbers. Too often we get just MPG without the speeds and that can be terribly misleading.


Is this table accurate for your vehicle?
.
The reason I ask is your vehicle performance seems a little different from results from other Prius. What I've found with my NHW11 and a report from an NHW20 owner and my wife's ZVW30:
.
Source data for NHW20 and NHW11:


Source data for ZVW30:


What I found with my NHW11, a 2003 Prius, there was no significant change in MPG out to 65 mph. But once it exceeds 65 mph, the mileage falls off significantly. In contrast, the NHW20 user report and my wife's ZVW30 don't have a similar MPG plateau or fall off. They follow the expected aerodynamic drag curve.

Your data at 55 mph has me really scratching my head. It suggests that there may be a slight dip or at least a flattening of NHW20 performance under 60 mph. This plateau is evident in my NHW11 data. It would be interesting if you could try a run at 65 mph in your NHW20 or better still, at 62 mph to do a head-to-head comparison with your 55-70 PnG. This would quantify the PnG improvement.

Thanks,
Bob Wilson

HI bob,

I need to get some disclaimers out of the way before I write anything else.

First and foremost: my Prius is a rebuilt salvage vehicle. It looks like a duck, talks like a duck, but it may happen to be different from a normal vehicle in some way that I am not aware of.

All of my numbers are by no means, a scientific recording of data. They are just based on my loose memories and what I can remember and apply to every car journey. The numbers are probably therefore at least 10% off, but as I don't write it down, I could not tell you exactly what happened.

The 55mpg quote is from when I made a trip to Lewisville (Dallas area). 280 mile trip, and except for maybe 30 miles exiting Houston and 30 miles entering Dallas, I had the cruise control set to 55mph for the whole way. I achieved 55.5mpg according to the MFD when I got to the destination. I must've had a hundred trucks pass me by, that was kinda embarrassing, but I heard 55mph was the most efficient speed to go at and wanted to see what I got. Arriving after a 300 mile trip with half a tank remaining is a good feeling!

One time, out of necessity, I had to get to a destination about 60 miles away from my current location with just one gallon remaining. So I PnG'd tirelessly until I got home. Luckily the traffic was pretty calm and chill and let me do my thing. I got about 60mpg.

Then another time I PnG'd on the highway home from a friends house 20 miles away just for fun. I achieved 68mpg on that stretch, I actually have a picture of that one on my facebook.

Something like 99% of my driving is in the city, amongst aggressive drivers, or with myself being aggressive. Therefore, my usual fuel economy does not top 40mpg often, so when I get higher than that, I take note! And skip a little, but I digress.

Regarding making some more trips at certain speeds, what do you need exactly, a 62mph trip with PnG or SS (steady state)? I'm willing to do it but it may take a few days to get a good opportunity to go on the highway again.


__

So basically my numbers may be way off, but I have a general idea what gives a good working PnG trip and so I was just advising Lutece of my findings.

[bwilson4web]

Originally Posted by toxicity

. . .
First and foremost: my Prius is a rebuilt salvage vehicle. It looks like a duck, talks like a duck, but it may happen to be different from a normal vehicle in some way that I am not aware of.

Excellent! I've read of several others and then there is the legendary AutoBeYours. Did you do this salvage recovery? My only curiosity is how are the tires wearing and the alignment?

Originally Posted by toxicity

. . .
All of my numbers are by no means, a scientific recording of data. They are just based on my loose memories and what I can remember and apply to every car journey. The numbers are probably therefore at least 10% off, but as I don't write it down, I could not tell you exactly what happened.

That is OK. It means you're not quite as Obsessive Compulsive about it. <GRIN>

Originally Posted by toxicity

. . .
The 55mpg quote is from when I made a trip to Lewisville (Dallas area). 280 mile trip, and except for maybe 30 miles exiting Houston and 30 miles entering Dallas, I had the cruise control set to 55mph for the whole way. I achieved 55.5mpg according to the MFD when I got to the destination. I must've had a hundred trucks pass me by, that was kinda embarrassing, but I heard 55mph was the most efficient speed to go at and wanted to see what I got. Arriving after a 300 mile trip with half a tank remaining is a good feeling!

No apologies needed! The essence of the scientific method is to test and your data is excellent. In fact, it fills begins to fill a gap that I have no data ... standard NHW20 performance at lower speeds.

Originally Posted by toxicity

. . .
One time, out of necessity, I had to get to a destination about 60 miles away from my current location with just one gallon remaining. So I PnG'd tirelessly until I got home. Luckily the traffic was pretty calm and chill and let me do my thing. I got about 60mpg.

Then another time I PnG'd on the highway home from a friends house 20 miles away just for fun. I achieved 68mpg on that stretch, I actually have a picture of that one on my facebook.

Excellent!

Originally Posted by toxicity

. . . Regarding making some more trips at certain speeds, what do you need exactly, a 62mph trip with PnG or SS (steady state)? I'm willing to do it but it may take a few days to get a good opportunity to go on the highway again.

No problem, we own these vehicles for years so when you get a chance, it would be interesting to fill-in this last row:

min mph	max mph	avg mph	MPG	model	comment
55	55	55	55	NHW20	experiment
55	70	62	60	NHW20	PnG test
62	62	62	. . .	NHW20	reference

.
This will quantify the PnG versus the equivalent steady speed.

BTW, we're finding our NHW11/NHW20s appear to have a maximum range speed of 18-20 mph. If I were in the desert with the next gas station twinkling in the distance, I'd be holding the speed at ~18 mph and on the shoulder creeping a far as possible with the last of the fumes.

Originally Posted by toxicity

. . . So basically my numbers may be way off, but I have a general idea what gives a good working PnG trip and so I was just advising Lutece of my findings.

Sharing data is great and adding an equivalent, steady-state speed completes the picture, especially from the same vehicle and driver. Since I grew up in Oklahoma, just keep a weather eye out for the winds. <grins>

Bob Wilson

[toxicity]

Hi Bob! Prepare for a lot of text here!

Originally Posted by bwilson4web

Excellent! I've read of several others and then there is the legendary AutoBeYours. Did you do this salvage recovery? My only curiosity is how are the tires wearing and the alignment?

I didn't do the recovery myself, I hardly know anything about the mechanics of cars I purchased it from a car dealer who had bought it at auction, after it had been rebuilt.

The alignment is fantastic, I can practically drive without my hands on the steering wheel most of the time! As for the tires, they have been really, really bad. I think. Again, I don't know much about cars, however two of the Integrities developed punctures in the sidewalls after about 15,000 miles of my driving, and the car had 7,000 on it when I bought it, so assume 22,000 miles on the tires. I have since replace them with Falken Sinceras, which are fantastic, and I have a warranty on the Falkens so if they pop, I can get them replaced free. Overall though I don't think the tires did too well.[/quote]

Originally Posted by bwilson4web

That is OK. It means you're not quite as Obsessive Compulsive about it. <GRIN>

I would like to be though! If I had the technical know how, I would hook up a netbook to the car to record mountains of data on how my fuel economy varies with speed and throttle pressure, maybe even have one of those scientific weather measuring devices attached to the car so I can measure the wind speed, humidity, temperature, etc and see what bearing those things have on fuel economy. They really should have a course in a college somewhere on the physics of fuel economy!

Originally Posted by bwilson4web

No apologies needed! The essence of the scientific method is to test and your data is excellent. In fact, it fills begins to fill a gap that I have no data ... standard NHW20 performance at lower speeds.

Whats a lower speed by your definition? Has no one tried crusing at 55mph? Serious question! I hope I'm not the only person in the world who actually drives like that

Originally Posted by bwilson4web

Excellent!

I should note that the examples I gave that merited that were both on the highway, I kind of missed stating that. I just wanted to mention it because I think someone said something about PnG being ineffective on the highway - well, in my experience, it is effective, its just that when you go above 70mph or so, the relative windspeed knocks your overall speed down so fast that it isn't worth it. At lower speeds though, like topping out at 60-65mph, the speed reduces slower and so you can get in more of those 99-99-99 segments.

Originally Posted by bwilson4web

No problem, we own these vehicles for years so when you get a chance, it would be interesting to fill-in this last row:
.
This will quantify the PnG versus the equivalent steady speed.

Ok, so all I have to do to fill out the table is cruise at 62mph? No problem! I think I can do that tonight!

Originally Posted by bwilson4web

BTW, we're finding our NHW11/NHW20s appear to have a maximum range speed of 18-20 mph. If I were in the desert with the next gas station twinkling in the distance, I'd be holding the speed at ~18 mph and on the shoulder creeping a far as possible with the last of the fumes.

I see what you are saying here, however, and this has a huge influence on my driving: I don't wish to present a hazard to anyone else on the road, and I don't want to give Prius drivers a bad reputation, so even on my last fumes, I will keep up with traffic; however, I WILL PnG mercilessly to achieve the maximum fuel economy. Typically, when I get down to that last pip, I will reset the fuel economy meter so that I can see how I am doing with just that one gallon, and get an estimate on how many miles I have before the "Add Fuel" warning comes on.

That said, how can you get the maximum range at 18mph??? From what I have seen, I can't get into the 40mpg's until I hit 30mph at least. I read somewhere on this forum that 48mph was the best speed for fuel economy, although that is largely impractical on both city and highway roads. When I am going for the max range, I will just let the speed at which I pulse go down by 50-10mph, maybe taking it as low as 25mph before slowly pulsing up again to 40mph.

Originally Posted by bwilson4web

Sharing data is great and adding an equivalent, steady-state speed completes the picture, especially from the same vehicle and driver. Since I grew up in Oklahoma, just keep a weather eye out for the winds. <grins>

Well I am happy to help! Just tell me what conditions I need to drive under, I shall have some data for you shortly!!

Originally Posted by bwilson4web

Bob Wilson

[bwilson4web]

Originally Posted by toxicity

. . . <about 18 mph, extreme>
I see what you are saying here, however, and this has a huge influence on my driving: I don't wish to present a hazard to anyone else on the road, and I don't want to give Prius drivers a bad reputation, so even on my last fumes, I will keep up with traffic; . . .

Imagine you have just descended into Death Valley at midnight only to discover the gas tank is almost empty. In the far distance, the other side, you can see the blinking lights of a gas station. The only other traffic are snakes and stinging insects and you don't want to have to walk towards the blinking lights with an empty gas can ...

Without other traffic, run the Prius at 18-20 mph, constant speed, and you will minimize how far you'll have to walk at 5 mph in the blazing sun and Death Valley heat. Now if you see another vehicle, put on the emergency blinkers and roll to a stop. See if they'll help. If not, 18 mph until the last of the gas is gone is your best survival strategy. <cue the "Twilight Zone" music.>

Originally Posted by toxicity

. . . That said, how can you get the maximum range at 18mph??? . . .

From a number of tests and experiments, we have this graph of the earlier 1.5L, NHW11 performance:

The "gray line" is the expected MPG at any given speed for the NHW11. The NHW20 should have a slightly better line but with a higher peak in the same 18-20 mph region. Notice those "black dots?" Those are the average leg speeds from the famous NHW20 marathon. <GRINS>

Then I've been known to pull a few tricks. For example, here is what I got after 10 miles at 15 mph:


If you really want to see some impressive numbers, try some of the low speeds ... say around a parking lot on a day when there isn't any other traffic. It is boring, so bring some good tunes. <GRINS>

So when you hear the "Twilight Zone" music, you'll know what speed to hold. <GRINS>

As for conditions, side winds of say 15-20 mph are OK. But if you have a head or tail wind, try and estimate the velocity and angle and we can show you how to estimate the effect. For example, straight at you would be the cosine of 0 degrees, 1, times the wind velocity added to the vehicle velocity. At 45 degrees, it would be about the cosine of 45 degrees, .707, of the wind velocity added to the vehicle velocity. For our purposes, this is close enough.

Bob Wilson