Fj,
same here, thanks for your feedback.
took it to the dealer today, no spcific codes or anything, but I was told that the quality of the gas plays a big role, and gas quality in this country is very bad. I use 95 octain premium, but still it is not actually 95 octain as I was told, much less than that.
hoping thing will improve when weather warms up

 

its not drastic but in short trips my engine does not get a chance to warm up to normal and when cold it stays in 8v till the temp guage hits the first hash mark. Snow on the road doesn't help either. although you don't have the snow (i assume), because of your short duration trips you may be experiencing the same cold engine conditions that I am experiencing. My morning commute never sees the thermostat even open by the time I get to my parking garage.

 

Jet,
We get snow occationally, no snow this year so far.
Yes, that is case, taking short trips in cold weather kills the fuel efficiency for sure.
what is your average MPG in your case? and what state are you in (Sandiego)?

 

This is a really insightful group of folks. Jet is right on the money on the short trip effect. Even the city cycle that determines the US city label has 45 mph driving stretches and goes for 10 km or so. Apparently Consumer Reports has their own city/highway cycle; the city is way more severe than EPA and the highway cycle is more lenient. The CR city/highway cycle for the two-mode is rumored to be around 15/25, with basically the same composite as the EPA. So Guss' city cycle is on par with CR's.

As has been mentioned previously, the trans temp has to get up to a certain temp as well to enable autostop, and it rises much slower than engine coolant. Basically 62 degF/17 deg C is the breakpoint (roughly). For every degree outside ambient is below this point, trans temp has to rise the same amount above to enable autostop. So on a 32 deg F/ 0 deg C day, trans temp has to hit about 92 deg F/34 deg C. Not exactly linear, but you get the idea. And trans temp doesn't rise much in 3-5km trips.

And the bad gas thing is probably contributing, too. The motor has knock sensors, so the ECM is probably pulling out a lot of spark advance to prevent detonation, therefore the engine is not running at its peak efficiency.

All I can say is try to run it at higher speeds periodically to keep from fouling your plugs and causing misfire. Maybe look into a good detergent additive to help out the local gas.

Sorry, Guss. You're sort of hosed on city mileage with your situation; short trips, hilly terrain, bad roads, and bad gas.

 

Kc
good to hear from you on this subject. Thanks for your feedback very informative.

What do you mean by "run it at higher speeds periodically to keep from fouling your plugs and causing misfire"
do you mean pressing harder on gas pedal, or driving the vehicle at higher speed when I get a chance ?

Thanks again

 

Forgot to add, after parking the car yesterday over night for 13 hours, the moment i started it, trans temp was at 15 c outside temp was 10c.
When I restarted it again in the evening, after parking It for 4-5 hours. Outside temp 15c trans temp was at 40 c.
We have a heat wave the next couple of days, expected highs in mid 20c. So I don't think I will have a problem with trans temp dropping below 15c. Hope this helps my mileage.
Will see how it goes.

 

can you change it to 2wd? i got 19+ city and 20+ highway with 2wd and 19/20 ave on 4wd auto.

 

I am on 2wd all the time.
Thanks

 

Great discussions guys. Sorry to hear that Guss lags in the city. I have noticed many other threads on just about all the hybrids out there wondering why their fuel economy is taking a hit. Now Dallas Texas is getting a foot or more snow. How's the 4X4 Mel?

Is it just me or do all hybrids take a hit that appears dissproportional due to colder weather?

 

A commute that short will really kill your MPG...even my commute which is around 4 times that distance is visibly hurting my MPG, which (in a Prius) is around 20 MPG and sometimes less for about the first 10 minutes of driving then goes up to normal levels (40+) in the remaining 10 to 15 minutes.

I think it's possible that hills could actually help MPG -- depending. Going up a hill is a form of energy storage, but without the energy conversion losses of the generator/battery chain. So coming down the hill you get it back. Here the advantage of a hybrid comes from having a smaller engine since regenerative braking plays less of a role. If you go over a series of hills without stopping, you could get an effect similar to pulse driving (a maneuver also designed to avoid mechanical/electric conversion losses) -- but while maintaining a constant speed. Unfortunately if you have stops coming down the hill it negates most of that, because the energy you stored going up just gets burned up in the brakes -- although how much of an effect that has depends on how your braking is divided between regenerative braking and friction braking. A stop at the bottom of the hill (which I typically have at the bottom of the one long hill on my way home) is probably the worst case, because you probably could have coasted a long way on the energy burned up in the stop.