149 MPG on a 52 Mile Commute: An Analysis

Hi everyone,

Had my Prime for just over 3 weeks now, and I've been playing around with a few different routes and driving styles to optimize my MPG. I think I've landed on a pretty decent approach. I'm sharing my driving strategy, complete with online tools and a few images to illustrate my route in order to share what worked for me, but also to solicit whatever useful tips other may have to optimize my fuel efficiency. The following is some data I took on today's commute:





First a few preliminaries:

• Round trip distance is 51.6 miles, mostly rush-hour highway driving but stop-and-go city driving as well.
• Temperature ranged between 34 and 40 degrees on the morning commute to work according to the console display; 45 degrees on the evening commute back home.
• Climate control set to 60 degrees in the morning, off in the evening.
• Heated seats both ways
• Elevation difference between work and home is 185 feet: descending in the morning, ascending in the evening.
• Battery fully charged in the morning.

The following graph shows the change in elevation of my round trip commute. I've also numbered the different stages of my route based on how the route or my driving style changed. Basically, my approach is to use EV Mode when driving in stop-and-go traffic and climbing steep hills, and switch to HV Mode when driving at highway speeds on a relatively level plane. I find that the mode is irrelevant when descending steep hills because either way the ICE shuts off when coasting.



Green: EV Mode
Red: Hybrid Mode
Purple: Toggled back and forth

Commute to Work
1. EV. City Driving. Top speed 45 MPH
2. HV. Highway driving. Cruise control set at 57 MPH (all highway driving at this speed)
3. EV. Highway driving. EV Mode turned on for steep incline.
4. HV. Highway
5. EV. Highway. Hit traffic. Stop-and-go for nearly 5 miles. Top speed 20 MPH.
6. EV. Parkway with 6 traffic lights on route. Top speed 50 MPH.
7. EV. City Driving. Top speed 25 MPH

Commute Home
8. EV/HV. Toggled between modes for city and Parkway with traffic lights. EV to accelerate; HV to cruise.
9. HV. Highway.
10. EV. Highway.
11. EV. City. EV battery nearly depleted upon arriving home - 0.1 miles left in electric range.

Would appreciate any suggestions for improvements anyone may have. Thanks!

 

Not much you can do about the distance to work, and 103 MPG is awesome. I wonder, have you noticed your breaking habits? I noticed when I changed my breaking habits by letting off the gas earlier when coming to a stop, my gas mileage started improving measurably. And obviously reducing speed will help as well (not telling you anything you don't know), although if you're traveling a 65 MPH road, then I supposed you really can't go much slower than 70.

What I love about owning this car is how dramatically my expectations have shifted in regards to good gas mileage. When I owned my Avalon, I was thrilled when I finished a trip at 32 MPG. Now I regard 130 MPG as a personal failure, LOL.

 

That's a great suggestion. I'll try EV Auto mode for a week or so, and see if that squeezes out a few extra MPGs.

Thanks!

 

Quick update re EV Auto. I've tried it for 3 days now instead of pure EV Mode with more or less the same parameters, and there has been no discernible difference. ICE engine didn't kick on at all in EV Auto mode.

 

Funny, I just checked back in to update much of what you just mentioned. I was playing around with different modes of driving, and found that two changes increased my mileage measurably:

The first discovery I made was switching to HV mode when climbing steep hills (which you apparently had already figured out). Steep inclines do a number on electric mileage. I suppose gas isn't as inefficient for this.

Second, I found that it's better to deplete my EV range entirely for the trip home so the last 4.5 miles of city driving is done with HV. This is counterintuitive, since city driving in electric is much more efficient than gas. But if you quickly accelerate, release the gas, and then lightly reapply your foot to maintain speed, then most HV driving can be done in electric. So it's almost like squeezing out a few additional electric miles even after burning through the EV portion of the battery.

In any case, making these changes, I noticed that yesterday under the same driving conditions with roughly the same temperature (30 degrees drive to work, 40 degrees drive home), my gas mileage was 165. Today it was warmer - 40 degrees driving to work, 50 degrees driving home - and my mileage was 182. So I can totally see how you're getting just over 200 mpg in the summer. Hopefully I will see similar results in the summer months

I'm still amazed by this car.