The "Holy %$%# It's Cold Out There" Winter 2017 Thread

[JasonPratt]

Why is your RAV4 hybrid CVT averaging 12.3MPG?  :o

Ah, good eye! There are two answers to that question (or maybe three).

1.) When the temperature gets very low, the big computer under the hood (sitting where the battery would usually sit) is programmed to collect and conserve battery power in order to be sure to have enough to help the 2- and 4-wheel drive protocols. Partly this may be due to cold batteries not having as much oomph (and while this is a hybrid limited, it isn't the version with the larger battery system), and partly this may be due to expecting to need power directed to various wheels at any moment on a slick road. Either way, I noticed a big difference in how the car directs battery output once the temps here started hanging around freezing. It suddenly stopped giving me any EV time for example (where at parking lot or traffic jam speeds the car runs totally on battery.)

Consequently, the battery doesn't discharge as much for acting like a supercharger, much less for low-speed maneuvering. Also, the engine tends to be directing more of its power to the battery more of the time (whereas usually the system relies more on slight friction from the turning of the wheels, especially while braking.)

2.) I was driving around on ice and therefore in the equivalent of low gear all the time. I am certain this didn't help. ;)


To this could be added:

3.) In my experience the MPG for "city driving" can be charitably called a highly selective marketing overestimation.  ::) :P I would dearly love to know what conditions the EPA tested this thing in to get the 40is city mpg, but driving around my town at 30 mph with occasional stop signs, I do well to average 30 to 32 with some variance.

On a full capacitor (and the capacitor discharges constantly when at rest, so it's normal to have 2 bars when starting after a few hours -- thus I mean after a 30 minute lunch where I've been careful to build up nearly full... full may be impossible and I've only ever seen one-bar-short-of-full once) I have managed to eke out some 40 mpg runs from the office to the house or from lunch to the office; even some low and mid-50s on rarer occasions. Once coming back from lunch I scored somewhere in the 70s. But to do any of that, I had to unrealistically game the engine with every trick in the book, on a run that was more downhill than up, and with more downhills before stops than uphills, and caaaaaarefully nursemaiding the (equivalent of a) tach at (the equivalent of) 2000rpm or less, even though that meant I never got much over 20 mph except when coasting downhill.

My little Sonic 6-speed (with turbo) that I traded in for this (because its value was about to plummet once Chevy announced last summer it was discontinuing the line), I could easily get over 30mpg in regular city driving without needing a battery to help. Its performance was quite nice, too: a fine clutch/stick set, decent gear ratios, engine tuning unique to the Sonic that gave it the tachs of a V8 (highway speed around 2000, idling well below that), and a weight-to-torque ratio comparable to a respectable sports-car.

To be fair the RAV, while by no means a large car, is significantly larger and more like a true wagon which can comfortably sit five adults (though the Sonic didn't lack for room and great seats in the back). So it's a heavier car, and the electric-engine converters on the wheels and its battery (even though not the largest available for the RAV) doesn't help its weight! It has a larger engine but not that much larger, so the engine has to work more, too. (On the other hand, I don't know whether a CVT weighs less than conventional automatics. I suspect so, but less than a manual?  ??? Maybe?)

Also to be fair, the RAV's performance characteristics are very decent. Even without help from the battery the 4-cylinder is punchy, and with the battery supercharging it, especially when not in Econ mode, it can generate some real g-force on acceleration. I was thinking of getting a Mustang GT (my first) in the short list of final cars, and I was not unhappy with the power on the road for this vehicle even in competition with that car. I mean, duh, it isn't a Mustang's performance but judging fairly it holds up by comparison.

(Note: the RAV has a "sport" setting that is DEFINITELY a lot punchier than "econ" setting, but I'm suspicious that this setting is something of a sham and is really no different than the normal middle setting. My key evidence, aside from suspiciously similar behavior, is that if you set the drivetrain to "econ" it stays that way in between leaving the car and coming back any time later. But if you set it on "sport" it immediately defaults back to "normal" the moment you turn off the car. It's like "sport" means nothing more than a couple of lights on the dashboard pretending you're in "sport" mode now. That said, I might detect better punch compared to normal. And compared to econ it's like night and day. But naturally econ helps mileage. I wasn't on econ in that photo, but I wasn't on sport either.)


But for people wondering about the 40mpg official city estimate? Yeah, don't believe that unless you've experimentally tested it in your travel route. 

I feel pretty safe inferring this has some bearing on that 12.3mpg after about 10 minutes on the road there.  O:-)

[mirth]

^the Gundam answer

[DoctorQuest]

^the Gundam answer

:DD

[Gusington]

 

[mirth]

https://twitter.com/growingwisdom/status/952149703143120896

[mirth]

https://twitter.com/jhickey62/status/952176307349131264

[GDS_Starfury]

mother doesnt approve!   >:(

[BanzaiCat]

 

[mirth]

https://twitter.com/RyanMaue/status/952546606754226176

[Arctic Blast]

-17 today, -9 tomorrow, -5 on Tuesday, -1 on Wednesday. Hope is on the way, folks!

[Staggerwing]

Soon you'll have your +1!

[Gusington]

^Soon we're going to have some more snow.

[mirth]

^Soon we're going to have some more redrum.

ftfy

[Greybriar]

-17 today, -9 tomorrow, -5 on Tuesday, -1 on Wednesday. Hope is on the way, folks!

No wonder you call yourself Arctic Blast. ;)

[BanzaiCat]

Supposed to have more snow tomorrow.

https://twitter.com/jhickey62/status/952176307349131264

That pic on the left looks like at first glance that there's two fires - one on the lawn and one in the street. ;D