Hey everyone, It's been hot these past couple days here in the Bay Area. My commute is about an hours drive on the freeway. And since it's been quite warm, i've been using my AC (75'F). I've noticed when i've exited the freeway, come to a stoplight and then when i come OUT of the stoplight the car is sluggish. Meaning the electric boost doesn't kick in and it's all engine doing the accelerating. The battery IS not drained or anything. I was just wondering if the air conditioner has something to do with this. Does the air conditioner have an affect the hybrid technology when accelerating? Does this make sense? I tried doing a search on this and came up with nothing. Any thoughts or help would be great.

 

I think that it's normal for almost every car, especially 4 cylinder cars, to experience a loss of performance when the air conditioner on. I can definitely feel a performance difference in my 2000 Honda Accord 4 cyl. when the air conditioner is on.

 

Just had a 98 degree day -- hottest yet since I bought my '07. *And* carting around four people instead of the normal one or two.

1 - to get sufficient cooling, I had to max the fan, set AC to On, and set temp to Low. (And it *barely* kept up.)

2 - the batteries wouldn't charge up. They depleted quickly to the 2-3 bar range, and then there was no forced regen. I'm assuming battery temp was too high to allow much charging. Note that the AC compressor in these conditions cycles both its electric and engine-driven stages, so it's drawing from the IMA and the ICE.

3 - significant hit in acceleration below 2,500 rpm, and it took longer for the engine to rev above that. *Bog*-slow off the line. This is the engine drag Mpress refers to, and I totally concur: 4-cylinders get their butts kicked by the AC compressor. You can literally feel and see the car lose a couple mph if the compressor cycles in while you hold the same throttle position.

4 - when at one point it auto-stopped with only two bars SOC and the AC all the way on, I started shifting to S to prevent autostopping altogether and to *try* to get more charging. (Only partially successful on the latter.)

5 - everybody get ready to wince, but in all honestly I was doing this as a test of my car's limits in this sort of situation: with four people, AC maxed in very hot temps, no autostopping, and heavy city traffic where most bets were off for efficient driving, my mileage for the afternoon was 28.9.

Well, at least now I know.


--doug

 

28.9 MPG is superb for those conditions.

Any regular car would be much lower.

 

OUCH! I do agree with Kenny, however...It would have been a lot worse in the average car...Heck, that's awesome FE for many cars in optimal conditions...lol

 

I notice that too at rare times when I have the AC on, that the IMA will not assist even with 6 or 7 bars of battery. It doesn't do it every day but there will be that one day where it's like driving a different car.

 

Definitely. (Never had another car that would do this -- even a Mitsu Mirage that was a fuel-sipper, next to nothing in similar conditions.)

Just . . . hate to do that to my HCH.

--doug

 

I noticed similar things lately in the hot temps. It's been well above 90 here the last few days. The car said 97 today. I have been happy with my AC. I set it somewhere between 75 and 80 and it keeps up just fine. I noticed very sluggish acceleration once and looked at the battery SOC and it had ZERO bars. I've never seen that before. It regenerated fairly quickly. I noticed sluggish acceleration again a day or two later and SOC was two bars, but it did not seem to want to regenerate quickly. Probably the heat. I still am getting reasonable fuel economy though. On the really hot days it's still above 45, and my display for this tank is still above 49.