'16 real MPG

Coming from an old Camry with the 3.3 V6 engine and 17mpg in town, I'd be thrilled just to get 30 with my new Prius!

I'm almost ready to buy my 2nd tank of gas. The screen says I'm averaging 60 to 62 mpg in city driving. I drive in the ECO mode.

The $25K I paid for the Prius could've bought a LOT of gas for the Camry... but what the heck, I wanted a new toy.

 

This is the key:

'Saving gas' is something we like just as others like 'Great sterio' or 'Wonderful paint job' or 'Cool wheels' or any one of dozens of car bling. Do they save money? Of course not because they appeal to what that owner wants in a car.

If someone wants to pull up some sort of cost-benefit ratio of a Prius versus some other ride, smile and let them babble on. Thank them for attacking your car and ask them if it is your turn to attack their ride. Did they get anything special and ask them 'did it pay off?'

The same ethic or family heritage that makes my blood not red but 'plaid' as in Tartan means it is as hard to get a penny from my clinched fist as anyone. I'm frugal and hate to burn money. So I'll spend more up front to pay less later and this is core to my Scottish heritage. No one gets out of this life alive but while we're here, don't waste what can not be reclaimed.

Bob Wilson

 

Well, how much is your life or serious injury worth? A new car is -always- safer and protects you better than an older one. Use that to justify the purchase if you need to.
I just shrug and tell the critics "I wanted it, and I can't take the money with me to the grave, and as I earned it I deserve to spend it on what I want."

 

My feeling are these two points.
1. Can't say why, but I just love fuel efficiency. Have kept track of MPG's since my first car in my teens.
2. I would rather my money goes to fine mechanical design and engineering than to sleazy oil companies and sleazy oil producing nations.

 

Does anyone have data on daily short trips in gen4, like 2 or 3 mile trips from cold start only? I've been working from home for several months and running average about 40 MPG with couple longer trips thrown in..
Wonder if the grill shutters help with short trip MPG.

 

The EPA Federal 2-day emissions test reports ~60 MPG in the cold-start, first of day drive. The Federal 2-day emissions test is 10-11 miles so this should correspond easily to the "2 or 3 mile" trips. But better still if you have access to an outside, 120 VAC outlet, consider getting an electric block heater. Just 30 minutes can make a measurable improvement in short-distance, MPG.

Bob Wilson

 

Have done a number of short trips in the 4 mile range. Avg about 47 MPG on those in LA weather in the 60s. In comparison trips over 10 miles averging 55 MPG or better.

 

2nd fill up! 466 miles this tank. 8.77 gallons of gas. 53 MPG calculated. Trip gauge indicated 54.8

 

My MPG dropped from 60 to 58.5 on my 4th fillup, due to week-long rain here in San Francisco Bay Area. I wonder what are the dominant factors contribute to this drop in fuel efficiency. Is it increased air density, water adhesion between tires and road surface, moist intake air etc?

 

Air density, some, but water has 800x the density of air. Pushing water from the front and sides of tires and water that impacts the car and then falls off. Windshield washers and headlights also drain energy.

Bob Wilson

 

Plus no two tanks will be identical, so many variables.

 

Is it bad to put on the day lights on? Or does it use so little power that it doesn't matter?

 

If you SOC starting was one bar and the SOC was at Max on the last fill up, and you could go 6 more miles with that SOC, then your miles = 472, and your mpg goes up to 53.8. You could probably get better than that.

Is there a chart that relates SOC to distance ?

 

There are some loads whose overhead is outweighed by the safety gained. I wouldn't worry about it.

Bob Wilson

 

Uh, no. Our Prius is not an electric car but uses and entirely different approach.

Once warmed up, the Prius does everything it can to run the engine at peak efficiency, power modes which is typically 10 kW / 13 hp or higher. When the car does not need that amount of power, the Prius banks the excess into the traction battery. As soon as it can, the Prius turns off the engine and uses the stored power to drive the car. In effect, the car is constantly turning the engine ON and OFF for 15-300 seconds while we drive. We soon don't even notice it until we find we're getting +50 MPG at the pump.

The least efficient power mode for an engine is when the throttle plate limits engine power. So the Prius engine uses engineering tricks to keep the throttle plate as open as possible:

• delayed intake valve close - this pushes part of the fuel air charge back into the intake manifold so the throttle plate can remain more open. In a perfect world, variable intake valve duration could eliminate the throttle.
  
• cooled exhaust gas - this makes the incoming air less combustible allowing the throttle plate to remain more open. It is especially important at higher power to prevent the catalytic converter from burning out.

Bob Wilson

 

High 60's to mid 70's off the interstate. My mostly interstate trip home from the dealer and had a lot of rain and you could tell it zaps the mpg. Maybe 54MPG in the rain driving 65mph. Manual says day time running lights affect MPG. AC does also but a window down is worse at higher speeds. All in all much more efficient for the first 1000 miles than any car I have ever owned.

 

3rd fill up. Mileage up a bit more
546 miles. 9.70 gallons. 56.2 MPG calculated. Display 58 MPG.

 

Well, my real world mpg (over 32k miles) matches Consumer Reports, but I admit I drove it like a normal car all it's life.

 

Somebody asked about short trips of 2-4 miles? Yeah, during a recent short trip the computer showed I was getting 147 mpg! Then I drive another 1/4 mile, and it suddenly drops to 104. Then down to 70, etc. I don't pay much attention to those short trip numbers.

I more interested in the "full tank fill-up stats." I was routinely averaging 61.3 during the last 3 tanks. Now I'm down to 57.6 on the current tank. I haven't done anything different, drive just the same, and the weather and temp haven't changed. I've even slowed down a bit... but it won't budge off of 57.

That's fine. It doesn't bother me. I'd be happy with "only" 40 mpg. A "Hypermiler" I'm not.
Just cruisin' the coast...

 

Maybe that short trip mpg a clue to the stellar mpg numbers starting to show up here, and on Fuelly and the like, even better than rated mpg. Could there be some short trip tricks the car is doing?? The front grill shutters might be a factor, but couldn't be doing that much.