Prius milage - why higher in city?

<div class='quotetop'>QUOTE(DaveLeePrius @ Sep 25 2007, 02:03 PM) [snapback]517506[/snapback]</div>

I also get much better gas mileage on the highway (50+, depending on wind and hills). Especially with cruise control on. In the city it gets better mileage than I would get with a non-hybrid car (40 - 45). But like all cars, city driving does not give you good gas mileage.

 

Excellent post Bob Wilson. While I have a hard time understanding the graph, the explanation more than covers it. I have been watching my consumption and energy monitors on my commute which is only 10 miles . Keeping it just under 50 does seem to shoot my mileage up. And keeping it around 40 does shoot it up higher, but I can't really drive that slow on the parkway. On my first tank still and even with the short commute it's still climbing, up to 45.6 now.

Problem is the long low grades. They cost gas to run. The only real good thing I have in my commute, is that all my stops are able to be glided to and braked slowly.



But anyway, I just wanted to say I appreciate your ability to translate your scientific process so well to the untrained mind ( mine ).

 

Well I accelerate pretty briskly but try to time lights and coast to red lights from way back. I never use B mode except for half a mile near the bottom of a steep hill. I have a daily commute of about 78km return with a short distance of 100km/h expressway some 80km/h some 70km/h amd most of my journey, about 23km each way in 60km/h limits. I encounter 40 sets of traffic lights each way and travel through the GPO of Adelaide a city of 1.5 million people. Apart from the steep hill near home Adelaide is pretty flat, some hills but not bad.

I get about 4.3L/100km on this commute consistently.

On a trip to Port Augusta and back, a little under 700km including some running around I achieved 5.2L/100km using cruise control at 110km/h and at one point while passing a truck I got up to 160km/h. (minimum impact because very quick)
As you can see, I get 5.2L/100km on the highway and 4.3L/100km in town there fore I use less fuel per mile in the city.

DaveLeePrius, can I ask you what sort of consumption did you record with you last car? Was it better country than city and if so how did your mileage compare to EPA figures?

 

kinda saying what others have said, but a few definitions

city: stop and go, average speeds around 20 mph... top speed no more than 35 mph

suburban or "small town": average speed 30 mph. heavy traffic but lights only every mile mostly, occasion congested areas, top speed 40 mph

rural: usually no lights. stop signs every 1-3 miles depending on routes. speed limits 50 mph... average speed can be near that.

we will forego freeways since we have very widely varying conditions on them as well.


now expected mileage..... city is lower.... MUCH lower than any other type of driving. be happy if you average 40 mpg in those conditions.

small town suburban... be ashamed if you cannot do 55 mpg... 65 mpg+ is not unusaul.

for rural... 52-56 mpg...NOTE: after two years of tracking data, this type of driving benefits the most from grill blocking. expect a full 2-3 mpg increase. for some in colder weather, expect as much as 5 mpg. block both upper and lower. in temps under 45 F u have absolutely no worries

 

kinda saying what others have said, but a few definitions

city: stop and go, average speeds around 20 mph... top speed no more than 35 mph

suburban or "small town": average speed 30 mph. heavy traffic but lights only every mile mostly, occasion congested areas, top speed 40 mph

rural: usually no lights. stop signs every 1-3 miles depending on routes. speed limits 50 mph... average speed can be near that.

we will forego freeways since we have very widely varying conditions on them as well.


now expected mileage..... city is lower.... MUCH lower than any other type of driving. be happy if you average 40 mpg in those conditions.

small town suburban... be ashamed if you cannot do 55 mpg... 65 mpg+ is not unusaul.

for rural... 52-56 mpg...NOTE: after two years of tracking data, this type of driving benefits the most from grill blocking. expect a full 2-3 mpg increase. for some in colder weather, expect as much as 5 mpg. block both upper and lower. in temps under 45 F u have absolutely no worries


*edit* dont know why i constantly get double posts...maybe jealous that Evan and Jonathan have 10,000 posts and i dont...hehehe

another thing to look at is your drive. you have instant feedback on the "mileage potential" of your route. i live on the slopes bordering the very southern tip of Puget Sound. doing so makes for a very scenic place complete with the of the best sources of fresh water available in the aquifers that are created when rain in the hills filters down thru the ground and emerges at the bottom in a fountain of sparkling water using only gravity.

but those hills will KILL your mileage. that adage "what goes up, must go down" does not work for efficiency. the amount you generate going downhill will not even come close to making up for what you lose going back up.

another thing that will help you is stay on multi lane roads, learn the lights. just doing that increased my mileage 2-4 mpg using the exact same route.

temps have been in the upper 30's in the morning, upper 40's to low 50's during the day, and i am about to post my all time record for winter driving. at this moment, i have driven 464 miles at 58.2 mpg. but that is because my route is much flatter.

dont have mix on this tank, but average for other tanks since moving in August. (didnt tack this tank because was hoping to have my Zenn and have honestly been impatiently distracted...looks like not until next week now. DAMN!!! ooops...sorry)

10-15% city
55 % suburban
25 % rural
5-10% freeway

 

<div class='quotetop'>QUOTE(DaveLeePrius @ Sep 25 2007, 12:03 PM) [snapback]517506[/snapback]</div>

My drive to run errands today in fact was 100% freeway free. Time consuming, yes, but
I think my average mpg was around 60-70 according to the computer. Most of this is because I coast
and let the regenerative braking kick in when I see a red light, and I have this route memorized so I have an idea when the lights will change. Also, I've noticed that the best cruising speed is about 45-49mph - you seem to get a better mpg rating according to the MFD than say 35mph (unless you're using the electric propulsion solely and not the ICE).

As for freeway, you figure you're always using the ICE, and there aren't really any points when it turns off, sans gridlocked traffic.

Paul

 

There have been some good answers here, but I like to look at it this way.

Why do most cars get better mileage on the highway than in the city? After all, on the highway you have much more aerodynamic drag than you do in the city when travelling slowly. Aerodynamic drag energy can never be recovered.

The main reason that city mileage is worse on other vehicles is because the kinetic energy lost during braking is wasted as heat. In the prius it is used to recharge the batteries.

There is nothing inherantly wastefull in stopping and starting. When an engine is accelerating gently it is actually pretty efficient. That is one reason than pulse and glide is so efficient.

An engine lugging along on the highway is not very efficient. Thus, car companies have developed cylinder deactivation technologies.