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Hi,

with the very low city MPG that I see, I wonder what is better ?

in this figure, we start on a red light and try to reach the next red light or stop sign 1000 feet further.

1. do a very slow acceleration at 1500 rpm for 10 to 15 seconds before cruising at 30 MPH and low rpm for the next 10 seconds ?
2. do a mild acceleration at 2500-2700 rpm for 5 seconds and then cruise at 30 MPH and low rpm for the next 15 seconds ?
3. do a hard acceleration at 3000 rpm + for 3 seconds and then cruise at 30 MPH and low rpm for the next 20 seconds ?

My ascent doe'snt like the very slow acceleration and the transmission is pretty harsh below 20 mph and 1500 rpm with rough simulated gear change. For low rpm acceleration, I would prefer a smooth linear CVT like I previously had in my 2015 CRV before a simulated gear like the ascent.

For the context, I live in a very dense urban area with a lot of stop signs and traffic light. In these area my daily commute gets me between 12 to 16 mpg at best. On the weekend, we frequently go out of the city and that way we can get 23 to 29 mpg depending of the load in the car.
 

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Over the last 2 tankfuls, city driving only, I'm getting 7-10 mpg! Highway was 26+ so not complaining there...but only 200 miles of city driving on a full tank? Costing me mucho dinero to drive this suv around town....
 

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Let’s assume 2 different scenarios. Both for 30 seconds

1– long slow acceleration
0.5gpm for 20 seconds, followed by 0.2gpm for 10 seconds =0.6*20/60+0.2*10/60=0.233gal

2– fast short acceleration
1.0gpm for 10 seconds, followed by 0.2gpm for 20 seconds =1.0*10/60+0.2*20/60=0.167+.067=0.233 gal

so in a perfect world it wouldn’t matter, but efficiency is important too. The engine starts putting out max torque at just 2000rpm. The torque curve is pretty flat after that and horsepower increases to its max at 5600rpm. Personally I try to keep the rpm in the low 2000 range when accelerating with decent results.
 

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I'm retired so I don't have a daily commute but the round trip to my golf course is 40 miles total with 15 stop lights each way, so 30 total over 40 miles. Traffic varies from medium to heavy most days.

Today when I left for the course my average MPG on the current tank of regular 87 octain gas was 23.3. When I arrived back home I checked and it was 23.8 so I gained half an MPG on this trip. This is pretty typical of my non highway milage.

Normal acceleration for me is 2,000-2,500 RPMs, at 3,000 I can easily keep up with any traffic. I never get fake shifting, which may be weird but it doesn't happen for me. I guess I have learned how hard I can push it and stay just below the shifting threshold or maybe my CVT is not normal, but it is butter smooth all of the time.
 

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I've been listening to a lot of the comments on here regarding MPG, particularly on the low MPG reports, and noticed a similar concern for myself. I've driven by Limited for about 12K, w/in 8mo, and pay attention to the MPG based on my driving habit a lot. I concluded that it will be very difficult to achieve the advertised city MPG of 21. I drive 70% on the hwy (20mi 1way=6mi city + 14mi hwy) and the best i've gotten is 21.7MPG.

If I were to drive in the city 70% of the time, the MPG will more likely be near 15mpg than 21mpg. You can do a quick test to confirm my hypothesis by monitoring your instant MPG while moving between 20-40mpg (staying below 3000rpm); it's not good!!!
 

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Hi,

with the very low city MPG that I see, I wonder what is better ?

in this figure, we start on a red light and try to reach the next red light or stop sign 1000 feet further.

1. do a very slow acceleration at 1500 rpm for 10 to 15 seconds before cruising at 30 MPH and low rpm for the next 10 seconds ?
2. do a mild acceleration at 2500-2700 rpm for 5 seconds and then cruise at 30 MPH and low rpm for the next 15 seconds ?
3. do a hard acceleration at 3000 rpm + for 3 seconds and then cruise at 30 MPH and low rpm for the next 20 seconds ?

My ascent doe'snt like the very slow acceleration and the transmission is pretty harsh below 20 mph and 1500 rpm with rough simulated gear change. For low rpm acceleration, I would prefer a smooth linear CVT like I previously had in my 2015 CRV before a simulated gear like the ascent.

For the context, I live in a very dense urban area with a lot of stop signs and traffic light. In these area my daily commute gets me between 12 to 16 mpg at best. On the weekend, we frequently go out of the city and that way we can get 23 to 29 mpg depending of the load in the car.
Sounds like the basis of another Seinfeld episode.
 

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Not sure how to put this without a blackboard, but here goes. (If this reads as condescending, please try not to take it that way, as it's not meant to be!)

True average mpg is NOT the same as the time average of two mpg chunks. 30 minutes of running 13mpg followed by 30 minutes of 25mpg does not necessarily give you 19mpg average over that hour. Why?

For the calculus-enabled, the derivative is over gallons dg, not time dt.

For the fractional thinker, it matters that the numerator is miles, and both numerator miles and denominator gallons can be increased in the cited 30 minute period to "take over" the average value. Time is not in the fraction components at all.

For the gimme-an-example thinker, try this extreme example to illustrate the point, and then back off to your own reasonable set of data from there:

First 30 minutes: Really bad city driving. Essentially idled for 30 minutes, rolling slowly on my street. Used half a gallon over 1 mile. 2.0mpg for 30 minutes.

Second 30 minutes: Normal highway, used 1.14 gallons over 30 miles @60mph. 26.3mpg for 30 minutes.

If we simply averaged the two mpg figures (as many of us are prone to do), we'd think that (2.0mpg+26.3mpg)/2 = 14.15mpg.

But no! Our end-of-tank calculation says that real mpg = total miles divided by total gallons used
= (1 mile + 30 miles) / (0.5 gal + 1.14 gal)
= 31 / 1.64 = 18.9mpg.

Why so high? It matters that in the second half hour, we went so far using that many gallons. The top and the bottom of the fraction got taken over by the highway part of the drive, even though it took the same amount of time as the city part.

So, don't think of your averages in city and averages on highway as time-based chunks for weighting. Weight them by gallons used in each (denominator), and a similar and maybe more intuitive thought (but slightly wrong) is to weight by the miles in each (numerator). My weekend kid commute is 15min city 15min highway, but I know that the city part is 4 miles while the highway part is 15 miles - and yeah the highway "half" of my trip factors almost 4X heavier into my mpg average for the whole trip.

(Note that a good car computer would match the end of tank manual calculation, but for some reason, probably marketing pressure, most of the cars I've driven are about 1.5-2.0 mpg optimistic. Yes, it pisses me off. But it'snunrelated to this, except that cars do the miles/gallon averages correctly and not time-based. They just skew it a little upward, the dorks.)

Mathematically yours,
F.S.
 

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(If this reads as condescending, please try not to take it that way, as it's not meant to be!)
Thanks for all the math goodies. All I know is that I very rarely travel on the freeway and get about 16 MPG. Remove all freeway driving and it would be around 14-15 MPG.
 

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I've been listening to a lot of the comments on here regarding MPG, particularly on the low MPG reports, and noticed a similar concern for myself. I've driven by Limited for about 12K, w/in 8mo, and pay attention to the MPG based on my driving habit a lot. I concluded that it will be very difficult to achieve the advertised city MPG of 21. I drive 70% on the hwy (20mi 1way=6mi city + 14mi hwy) and the best i've gotten is 21.7MPG.

If I were to drive in the city 70% of the time, the MPG will more likely be near 15mpg than 21mpg. You can do a quick test to confirm my hypothesis by monitoring your instant MPG while moving between 20-40mpg (staying below 3000rpm); it's not good!!!
I think that's because the EPA tests for "city" are absurd for any metro area, and only apply to what metro area people would consider small towns. For instance, we went through numerous cities on our road trip that have only a few thousand people, and their higher end speed limits of 50mph and 60mph.


The highway ones also don't take into account places like Utah, where highway speed limits are 80mph.
 
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