Archives

Has anyone experimented with the impact of wind on FE? Here is part II of a very basic experiment we tried. Remember, we do not claim to be experts but we hope you might find the results helpful and/or interesting. :)

:flag: Wind Speed Effect on Fuel Economy:flag:

How much effect does wind direction have on fuel economy using a 2006 Honda Civic Hybrid (HCH II)?

Does wind effect the amount of time it takes to go from 0 to 35 mph in the HCH II?


We do not claim to be experts, however, from the data collected, at least 2 items appear to be evident. 1) The headwind does seem to have a significant impact on fuel economy, and 2) we did not see a significant impact on the amount of time it took to travel from 0 - 35 mph in our HCH II. In other words, the engine seems to supply sufficient power to get the car up to speed in a headwind (no significant time difference from 0 – 35 mph between head and tail wind) but fuel economy is improved significantly with a tail wind.


Methodology

For more valid results, it was necessary to conduct this study 2 different days – 1 day with winds out of the North North West (NNW) with wind speeds of 5 mph or more and another day with winds out of the South South East (SSE) with wind speeds very similar. Although the road appeared to be mostly level, we wanted to be certain that slight variances did not have an impact on the results.

We completed 3 sets of testing for each of the 2 days. We drove one mile into a headwind of 5 miles per hour (MPH) or more, turned the car around, recorded Trip A miles per gallon (MPG) meter at precisely a distance of one mile, reset Trip A MPG meter, and drove the same distance in a tailwind and then recorded the MPG. We traveled from 0 - 35 MPH keeping the revolutions per minute (RPM) just under 2000 until we reached 35 MPH and maintained this speed for the remainder of the one mile stretch. We also recorded how long it took for us to go from 0 – 35 MPH and how much time to complete the total 1 mile stretch.

The car was driven for 20 minutes or more and fully warmed-up each day of testing. Ed drove the car as Drew recorded the results.

We recorded: MPG, Wind Speed based on Kestrel 3000 Pocketweather meter, Temperature based on reading recorded from car’s computer readout, car’s MPH, Time from 0 – 35 MPH and total 1 mile distance (under 2000 RPM).

Conditions
Fairly level road, headwind of 5 MPH or more, sunny, relative humidity 34% (test 1) 45% (test 2), approximately 1:00 PM central standard time, traffic was not a factor, tire pressure was 55 pounds per square inch (psi), all windows were up and fans were off, the gasoline tank was half full with regular unleaded, and location was rural Plainfield, IL.



http://www.cleanmpg.com/photos/data/500/Data_Collection_ChartII.JPG


Results


Test 1: NNW winds
Average MPG with headwind: 58.2 MPG
Average MPG with tailwind: 69.1 MPG
Outcome: There was an increase in Fuel Efficiency of 18.7% with tailwind

Test 2: SSE winds
Average MPG with headwind: 57.3 MPG
Average MPG with tailwind: 68.4 MPG
Outcome: There was an increase in Fuel Efficiency of 19.3% with tailwind

Combined Test 1 and Test 2:
Average MPG with headwind: 57.8 MPG
Average MPG with tailwind: 68.8 MPG
Outcome: There was an increase in Fuel Efficiency of 19% with tailwind



Materials and Equipment

-Kestrel 3000 Pocketweather meter
-Stop Watch
-Chart for recording
-Compass
-2006 Honda Civic Hybrid (HCH II)
-Writing Utensil



Discussion



We do not claim to be experts, however, from the data collected, at least 2 items appeared to be evident. 1) The headwind did seem to have a significant impact on fuel economy, and 2) we did not see a significant impact on the amount of time it took to travel from 0 - 35 mph in our HCH (http://www.cleanmpg.com/forums/glossary.php?do=viewglossary&term=24)II. In other words, the engine seemed to supply sufficient power to get the car up to speed in a headwind (no significant time difference from 0 – 35 mph between headwind and tailwind) but fuel economy was improved significantly with a tail wind.

Although we had to wait a few days to have the correct headwind for both tests to match road direction, you can see from both charts that the results regarding the impact of wind direction were similar implying that the degree of MPG change was mostly related to wind direction.

Also interesting to note was that the best MPG run was 73.2 with a tailwind and 62.3 with a headwind both recorded during the first test when temperatures were a bit warmer (approx. 68°F with test 1 and approx. 48°F with test 2). These tests also demonstrate the excellent MPG possible with the 2006 Honda Civic hybrid. Some of the same technological advancements should be included in the gas engine of all vehicles such as providing 2 spark plugs per each of the 4 cylinders where both spark plugs fire together when more power is needed and when 1 spark plug fires just before the second one to maximize fuel combustion for best fuel economy.

Hi Ed:

___35 mph is where the ICE is barely loaded and wind may have a much more significant impact on ones FE then if the ICE were loaded up at a higher RPM. Can you try your experiments at maybe 50 - 55 mph as that is where the results should be much closer? I would be very interested in the differences at that speed although I am guessing as to the outcome.

___Good Luck

___Wayne

Hi Wayne: Unfortunately we had a very difficult time finding a flat road for a full mile that lined up with common wind directions. The speed limit on this stretch of road is 35 mph. Sorry. :(

Wayne ~ Also this is a more common speed for us lately.

Hi Ed:

___There is a stretch of frontage road just up I-55 from you that may suffice? One section is between Rt. 6 and the Des Plaines River bridge on the East side. Run up there for some testing. There is a slight incline/decline after the short climb depending on direction but with a back and forth, they would even out.

___There are some better stretches even further up where the route is practically flat between the Kankakee river and Rt. 113 near Coal City on the west side of I-55.

___Good Luck

___Wayne

We'll have to check it out sometime.

Is anyone else trying something similar out there? Or any more informal scenarios where wind is impacting FE?

Here is a guy who seems to have some good info, check out:

http://privatenrg.com/index.htm#RearWheelSteer

He figures you could get a 15% mileage increase by steering the rear wheels to align the body with the wind!!

Gary

Gary ~ Thanks for the information-- interesting.

Not to hijack the thread, but my last two days of commutes have resulted in an averge mpg of 65 and 59 mpg when I am used to seeing 74 mpg. There has been a northeaster (storm) blowing through our area that will affect our area for the next couple of days. The rainy winds have been pretty steady at about 25-30 mph with gusts to 50 mph.

Is it safe to assume that this is the major culprit to my decrease in FE? It feel like I am dragging a trashcan under my car when I try to pulse and glide.

Oh well, I have lost 6 mpg on this tank in the last 100 miles; so much for my best tank average. :( :confused: :eek:

Theres no secrets about wind. It sucks! Yesterday was yet another prime example.

8 mph wind out of the south.

Going to work with the tail wind and 29F temps. 54 mpg.
Going home with headwind and warmer temps of 57F. 44 mpg.

The wind was the player, not the temps.

psy

Not to hijack the thread, but my last two days of commutes have resulted in an averge mpg of 65 and 59 mpg when I am used to seeing 74 mpg. There has been a northeaster (storm) blowing through our area that will affect our area for the next couple of days. The rainy winds have been pretty steady at about 25-30 mph with gusts to 50 mph.

Is it safe to assume that this is the major culprit to my decrease in FE? It feel like I am dragging a trashcan under my car when I try to pulse and glide.

Oh well, I have lost 6 mpg on this tank in the last 100 miles; so much for my best tank average. :( :confused: :eek:

If the wind direction and speed stay fairly constant over the course of a day's commute. so you are getting a headwind on one leg and a tailwind on the return leg, then the effect of the wind will mostly cancel out. And if you reduce your groundspeed on the headwind portion of the trip to cancel out most of the increase in airspeed, you can actually come out ahead on FE. But you mentioned rain. Wet roads can seriously kill your FE, especially when they are overflowing with water from a heavy rain.

Hi Chris ~ Thanks for the practical example. Like you, we are finding that wind does play a major role-- larger than we first thought. And sometimes by the time we return, the wind direction/speed etc. is not the same.

Any other examples out there?

Hi Ed:

___The following was yet another example of winds having a great effect on ones FE. The results were achieved with an ~ 10 mph head/tail wind on the first round and a 15 - 20 mph head/tail wind on the second leg.

“Tbaleno takes the Gloves Off” w/ his CVT based HCH-I using P&G ;-) (http://www.cleanmpg.com/forums/showthread.php?t=596)

___Good Luck

___Wayne

Interesting. Thanks for the example. :flag:

On my recent trip to Phoenix I achieved my best tank ever on the way there averaging 36.7mpg. On the way back I only managed ~32mpg. Other than less optimal drafting possibilities there was a 25-30mph crosswind the whole way back. I feel the crosswinds were the greatest factor in the reduced mileage on the return trip.

Thanks for the example. :flag:


On my recent trip to Phoenix I achieved my best tank ever on the way there averaging 36.7mpg. On the way back I only managed ~32mpg. Other than less optimal drafting possibilities there was a 25-30mph crosswind the whole way back. I feel the crosswinds were the greatest factor in the reduced mileage on the return trip.

Don't know how I missed this post before. I know what an effort this was, and the patience it must have taken. ;)
Wonderful job. :)

Thanks... yes, this was tricky trying to test under the same conditions but we had fun doing so. Cheers :flag:

Don't know how I missed this post before. I know what an effort this was, and the patience it must have taken. ;)
Wonderful job. :)

I just returned from a 700 mile trip-- 350 miles each way (mostly highway). I was able to pull off 61.1 mpg. On the way to the location I had a strong 15 to 25 mph head wind and I kept my speed to btw 55 to 60 mph and stayed a distance behind a tanker truck to avoid small stones and debris (I averaged a little more than 49 mpg). On the way back, I had a similar 15 to 25 mph wind but from the side (west wind as I was traveling north). This time I kept the speed btw 60 to 65 mph and I was able to be a bit closer in my drafting as small stones and debris on the shoulder were not a factor (I averaged a little more than 71 mpg).

I am beginning to learn a few tricks for safely driving in strong wind and still receive acceptable FE. For example, if cross winds are from center median toward right shoulder, debris from big trucks is not as much of a factor as the debris is blown off the highway and not onto my car.:Banane30:

I was very happy with 61.1 mpg especially for mid-January with temps around 20°F.

Any other wind tips?

Hi Ed:
I was very happy with 61.1 mpg especially for mid-January with temps around 20°F.___Happy? I would have been ecstatic!

___When the 20 + mph side winds rise in our area, I will surf the opposite side of any vehicle as it helps tremendously. I hope that helps? Tail Winds, I am HS P&G’ing like crazy to take advantage. Head winds … Either find a slow speed target to duck in behind or really drop her down to the minimums and drive and fight … repeat :(

___Good Luck

___Wayne

On the way to the location I had a strong 15 to 25 mph head wind and I kept my speed to btw 55 to 60 mph and stayed a distance behind a tanker truck to avoid small stones and debris (I averaged a little more than 49 mpg). On the way back, I had a similar 15 to 25 mph wind but from the side (west wind as I was traveling north).

Ed --and others--I'm curious how do you "know" the wind speed when you're driving--do you take your pocketweather meter everywhere and take a reading before you set out? A wet finger? Can you estimate pretty much by feel while driving?

Hi Tarabell:

___I cannot speak for anybody else but I know almost every flag along my daily grind and I watch for the tell-tale “Tales of the Flags" in terms of both direction and speed each and every time I drive by.

http://www.cleanmpg.com/photos/data/500/American_flag_wind_conditions.jpg
View off my back deck describing both wind direction and speed within the neighborhood.

___Good Luck

___Wayne

Wayne-- thanks for the nice picture. I use similar methods but also use the weather band radio.

:) My son decided to share this info for a science fair project @ his school. He was awarded a silver ribbon for his efforts and generated a lot of disscussion about hybrid technology in his school. We hope others decide to join us in trying to improve FE and helping to reduce gas prices.:Banane22:

Hi Ed:

___Does your son’s schools have any kind of Science or Environmental fair coming up? If so, consider taking your HCH-II to the school as your sons stand alone exhibit. He can describe all the parts and functions during the fair and you can offer teachers and administrators rides afterwards so they get a feel for high FE driving and what the HCH-II is really worth when driven properly …

___Good Luck and congratulate your son for me!

___Wayne

Thanks for the great idea. I am certain he would be able to do so.

Hi Ed:

___Does your son’s schools have any kind of Science or Environmental fair coming up? If so, consider taking your HCH-II to the school as your sons stand alone exhibit. He can describe all the parts and functions during the fair and you can offer teachers and administrators rides afterwards so they get a feel for high FE driving and what the HCH-II is really worth when driven properly …

___Good Luck and congratulate your son for me!

___Wayne

I had a Highway trip to take yesterday and did some tests. At 60mph on CC I was getting about 54mpg (engine still breaking in). As an 18 wheeler passed, I increased my speed to match. I was drafting about 1.5 seconds behind at around 65 to 70 mph. I was getting about 65 mpg. I know drafting is discouraged, but I couldn't resist. One thing I did notice is that there is a distinct spot that you can hit right at the end of his eddies. I'm sure there is a sweeter spot up at his bumper, but I'm not nuts. Anyway... if fell more than 1.5 seconds back, the car would shutter as his eddies hit, and my mpg would drop to about 45mpg. If I acel'ed back through the shutter of eddies, I'd pop back to 65mpg.

The funny part is that there was a ford Expedition drafting off of me (about 1.5 seconds back). I don't think the Prius gave that much of a wake, but it did give me a laugh.

Anyone from the upstate New York area just south of Watertown, NY where they have received close to 100 inches of snow the last 4 or 5 days with high winds as well?

We just beat our 89.7 with our new best record of 94.0 MPG. :D We believe the wind was a major factor in this major accomplishment.

On this tank, we traveled 282 miles on mostly flat roads in the midwest. We had primarily a tail wind of approx 8 to 12 miles per hour. The wind switched in our favor for the return trip as well. The average temp was 60 degrees, with an average speed of 50 mph :}

We are getting closer to our goal of 100 mpg. :D :D

:flag: :bananahuge: :flag:

Great job! What was the distance and I am assuming it was a round trip? I made a trip from Maine to Ottawa, Ontario into a pretty strong headwind, travelling about 60-65 mph on the interstate at temps around 10 F. My FE was about 39 MPG, where my typical FE would be about 50 mpg without the headwind at the same speed and temp. The headwinds hurt the Prius as well. Slowing down is a good plan, but on a 6 hour trip, my wife would have been quite upset if I had slowed down, I can only get away with that on trips of 3 hours or less.

Dennis

Yes, on long trips it is hard to go to slow. The trip was a round trip where I stayed the night. What was very uncommon was the wind changed directions so I had a tail wind for both ways. :)


Great job! What was the distance and I am assuming it was a round trip? I made a trip from Maine to Ottawa, Ontario into a pretty strong headwind, travelling about 60-65 mph on the interstate at temps around 10 F. My FE was about 39 MPG, where my typical FE would be about 50 mpg without the headwind at the same speed and temp. The headwinds hurt the Prius as well. Slowing down is a good plan, but on a 6 hour trip, my wife would have been quite upset if I had slowed down, I can only get away with that on trips of 3 hours or less.

Dennis