36.2 MPG for trips less than 2 miles not good

I thought that also til I thought about my Vibe gt. It will get much less than that in 2 miles of city driving. Should you extend your 2 miles into 4 your mileage will go up a lot. Not running on electric immediatly upon start up causes short trips to suffer.
Dan

 

Is this when going about 2 miles on a cold engine?

The Hybrid Synergy Drive in a Prius still needs the internal combustion engine (ICE) to be warmed up. If it’s not warmed up, the system won’t turn off the ICE when idling at stop lights or when “gliding”. So it’s likely that the car won’t go into an EV-only state in that short trip of yours, which is why you’re seeing such a low MPG number. (For a lot more technical info this post has details about all of the “stages” of Hybrid Synergy Drive warm-up.)

In fact, in most cars MPG is affected when the engine is completely cold (usually because the car will burn a higher fuel-to-air ratio until the engine is at it's most efficient temperature). This is why an oftenly repeated fuel saving tip (not just for hybrids) is to do all your errands in one trip, so you don’t have to take several trips with a totally cold engine (time it sits in a parking lot is usually not enough to totally cool off the engine block).

Prius C is great for short trips and stop-and-go traffic (where most cars suffer MPG loss the most due to idling), but the rules of physics (efficient fuel burn temperature, motor oil viscosity when at optimum temperature, etc) still apply. If you’re extremely concerned, you can look into having an engine block heater installed (and simply plug in your car into an electrical outlet timer and have it turn on for two hours before the work commute) — that way you can have a pre-warmed engine for that extremely short commute. (Rescinding this block heater advice since I do the math a couple posts down and it doesn’t work out for such a short trip.)

 

In addition to the engine being cold, if you are not extremely careful to keep the car in the EV range while doing it, getting the car moving from a complete stop is where you will use the most gas. And if your wife has any stops on the two mile trip for lights or left turning traffic, etc, the same situation presents itself each time. This is why Consumer Reports city mileage rating was only 37 mpg. Their city driving course is short with several stops.

As others stated, your mileage will rise dramatically with a just a few more miles to the trip. I have an 8-10 mile stretch during my commute, after I stop at Dunkin Donuts for a coffee. From there to work, my average speed is between 35 and 45 and I have 5 stops. I have gotten as high as 76.3 mpg on that short stretch, and can get in the 60s without even worrying about the ECO score. Two miles is just a very short trip, but I guarantee you that no other car will get better gas mileage doing it than the C, short of an all electric vehicle.

 

Anyone installed the engine block warmer? Will this help eliminate this problem?

 

Block heater is a good idea. Did you notice he said his wife is driving? My wife is pretty concience of the ScanGauge in our Vibe and brags to me sometimes about how she does. But, she has not driven the C enough to know just how to get mpg. In fact, in two weeks I think I have let her drive once, maybe twice, so I can not blame her for lower numbers, yet.
I still think you are going to be very pleased with the C. Just give it a little time.
Dan
who has found himself coming to rolling stops, only, and looking for cops at the intersections. Keep those wheels turning.

 

Here’s a post with someone on a 3rd Gen Liftback that got a very slight improvement (35mpg ->40mpg) in the dead of winter (so the heater doesn’t bring the engine up to fully-warmed temperature).

They do note down that thread that depending on where you live, running the engine block warmer for over two hours for such a short trip is almost definitely costing more than the gasoline saved. (I believe the one available on the PriusChat Shop is a 400W heater.)

Doing some quick math:

Assuming a 400W heater plugged in for 2hrs and $0.1190/kWhr (U.S. residential average for June 2011-May 2012):
0.4 kW * 2 hr * 0.1190 $/kWhr = $0.0952 (~$0.10)

Now, comparing the price for your 2 mile trip with 36.2 and 50 mpg (which is still unusually high for even a pre-warmed cold start) and assuming $3.699/gal:

2mi / 36.2 mi/gal * 3.699 $/gal = $0.204
2mi / 50 mi/gal * 3.699 $/gal = $0.148

That's just a ~5.6 cent savings for your 2 mile trip. Which was paid for with 10 cents if it’s your engine block heater creating that mpg difference — so, it was actually 4.4 cents more expensive versus just going ahead and driving the car at 36.2mpg. (And note this is still a best case scenario since 50mpg is unlikely.)

Now, if you were to change it to a 5 mile trip at 40mpg (since trip length leads to warmer engine and slightly better mpg) vs 50mpg, you’d end up with:

5mi / 40 mi/gal * 3.699 $/gal = $0.462
5mi / 50 mi/gal * 3.699 $/gal = $0.369

...or a 9.3 cent difference; still not even breaking even if you spent 10 cents to run your heater.

These are all optimistic/unrealistic numbers, but the point is that the two mile trip is so short that essentially *nothing* will substantially affect the cost of that short commute. Every car has this issue.

Assuming same gas price as above — your cost per mile for 36.2mpg is (1/36.2*3.699) 10.2 cents/mile; for 40mpg it is 9.2 cents/mile; for 50 mpg it is 7.4 cents/mile. The longer your trip, the higher the mpg will rise, so it's in your best interests to optimize your habits for that.

(I've edited my prior post to scratch out my advice to look into an EBH since clearly the math doesn’t work out at all for a two mile trip.)

 

53 is not for short trips. It is for city driving that matches the EPA city cycle. If you drive smartly on a warm engine, you can get in the 80's mpg in local driving. Give it some time, and you'll gradually get a little better, but two mile trips will always hurt the average big time on cold starts.

Our winter tanks can be as low as 40 mpg in our liftback 2010 if the tank is dominated by our 1.5 mile commute. Summer tanks approach 50 mpg on the commute. We average 50.5 mpg lifetime, as longer local trips and highway trips help the average.

 

If you can, I would suggest biking for trips shorter than 2 miles. IMO the time it takes is very nearly the same especially if there are multiple stop signs/lights. On top of that its better for your health and for your car (as i've heard that short trips are not good for your car anyways).

 

Please see Car and Driver: The Truth About EPA City / Highway MPG Estimates | PriusChat to learn more about the EPA test.

In the EPA tests, besides not driving driving on a real road but rather a dyno instead and not measuring actual fuel usage, the only two cycles that start on a cold engine are 31.2 minutes long and simulate an 11 mile distance.

Perhaps the CR city test results at The most fuel-efficient cars and Best vehicles for city & highway mpg more closely reflect what you're doing. See last page of http://www.consumersunion.org/Oct_CR_Fuel_Economy.pdf for a description of their city test (vs. the old EPA method).

 

Two mile trip??? Ride a bike, Fill the basket up with flowers, enjoy!!!

 

I get about the same on a two mile trip to my daughter's. If I don't stay too long, and the car stays warm, I get 60 plus on the way home. Just takes the little rascal a bit to warm up.
I have also found myself taking routes with less stop signs, around town. Getting out of this town eastbound we must climb a big hill, 2 of them. I figured out how to miss those two hills. 3 more stop signs but hey, I like the difference in mileage getting onto the 4 lane.
Dan

 

I've also changed my route ( three times) to avoid hills! Watching the instantaneous reading approach 70 MPG or higher is addicting!

 

^^^
Make sure your route changes result in reduced fuel consumption. Changing routes just for higher mpg numbers but that result in greater fuel consumption is counterproductive.

 

You got that right. I can't get my eyes off the Ultra-Gauge and main computer screen. I now know every little "rise" in town and can tell folks which routes have the least stop signs. My wife is not fond of me "rolling" through stop signs to keep the car moving either. Got to stop that.
Dan

 

Others have said the same, but I'd try to figure out a way to ride a bike every once in a while. 2 miles distance can be done without sweating, so all you need to do is figure out a route that she feels comfortable riding. 1 time per week will improve fuel economy by 20% (my math says it will take your 40.3mpg up to 50.8mpg)

 

I can get anywhere from 89.99 MPG to 20 MPG driving on base(less than 2 mile trips). Accelerate really slowly, that's what i do.

 

"Fuel used this trip" is a useful data point for common destinations.