Loaner Camry Hybrid getting better economy than my Prius

Tideland is speculating that you are trying too hard. This is a common error. Try driving more aggressively. Granny driving will often reduce your mileage if you don't fully understand when to do it and when to not.

Tom

 

How far is your typical trip?

 

Do you have the heat on all the time? Only put the heat on after driving for five minutes; if tolerable, try going without it.

 

What's that like?

With "granny" being a 1 and "aggressive" being a 9 on a scale of 1 to 10, try "brisk" instead. That's about 7.5 on the scale. You'll lead the pack, but not by a whole lot. It works out to a 4.93 l/100km (47.7 MPG) lifetime average for me.

Brisk takes advantage of the umph the electric motor can provide and gets the engine into an efficient RPM quickly.
.

 

Do you use "B"?

 

Ya know what? These people have the same problem and don't even realize it.

Look at the MPGs....They're doing many many short trips. It's a runabout for a University.

 

As to why FE has dropped over time, I would also look at the air
cleaner, MAF sensor (underneath the air filter). Don't remember if
you good folks in Canada have rear drum or disc brakes. If the
former, a shoe could be dragging a little.

Sounds like the HSD; engine, catalytic converter, and HV battery are
not getting fully warmed up during the short trips. As a result, the car
is not operating in its most efficient mode.

Using the heat in the first 5 min. or so makes a bad thing, the
low MPGs during the initial warm up period, even worse.

Getting to S4 requires getting up to 35 MPH. So, an otherwise
good route with speeds at or below 30 MPH could also be contributing.

Using either the front or rear defroster prevents the ICE shutting down
when at a stop before the HSD, etc is fully warmed up.

You might consider using an electric block heater to start the day with
higher ICE coolant temps.

 

You can join my 35-40MPG club, you seem to qualify.

FWIW, I recently moved and my commute is longer. For the winter, I used an internal 20$ electric heater. Plugged to a timer, on 1h before I leave. Some winter days it got to -20c!
Time savings, not having to remove snow/ice, priceless !

So for the first 5 minutes or so, I would drive with no heat at all to the cabin, allowing for the motor to warm up. Windows being all hot & such, no problem until the highway speeds, where I would turn on the defrost, but not too much.

So for winter driving, I was getting 6.5l /100km. That's with wet pavement, winter tires, etc. So it's quite good.

Now that the weather is nicer, I did a Reset. I'm getting in the 5.5l range, but I still have the winter tires to change.

So before, my daily commute was about 4km, and always got in the sixes.
Now, my commute is 20km, in ideal conditions, I've gotten 3.8l on a tank with no weekend driving.

Just remember, you're still polluting 1/6 that of a Honda Accord !
(driving those same KM's)

 

Cold winter weather and winter fuel will both contribute to poor fuel economy. Around Seattle, my lousy winter (non-hybrid) economy started recovering about two weeks ago, but is still nowhere near summer levels. Does your pattern fit the seasons? Maybe not, as August is much too early for this to start.

 

I was wondering, does the Prius engine also have one of these mechanical thermostats that would pop open and close or is it all electronic? My E46 BMW was always running too cool, because the thermostat snapped its' plastic retaining clip. [BMW used plastic in that car in places where metal should have been used instead].Replaced it and the temperature needle went back to the middle. It's never cold enough here for an always open thermostat to be a problem, but a friend of mine said it's bad for the engine and the CAT won't work properly. You'll just use more fuel.

 

It's a mechanical thermostat. It nominally opens at 82°C, but a range of 80°C to 84°C is permitted. Picture:




Picture from Autohaus Arizona.

The Prius generally has electrics/electronics rather than complicated mechanics, but simple mechanical devices in preference to complex electronics. The indicator flasher makes its 'tick' noise mechanically, which is why the relay is in the junction box by the driver's knee; the timing relies on the lamp's electrical resistance, so resistances (or a new relay) are required if replacing the lamps with LEDs. Relatively primitive, but reliable.