When to let IMA kick in

[mikejbb]

I've had my 2011 since June 21, 2011 and have about 3,700 miles so I'm a retired driver and haven't been on any trips yet. So 90%+ of my miles are city. And a lot of that has stop signs with no traffic. So I've started to down shift at 9 mph to stop the IMA from turning off the engine at 7 mph for the < 1 second at the stop sign. Then I shift to D and then go. I do that because I expect the restarting of the engine every block or 2 would use up the IMA battery and then when I'm sitting at a stop light for a minute or 2 the engine would stay running.

My ? is how long should you expect to be stopped to let the IMA turn off the engine? Is 10 seconds long enough? I expect one minute is enough. The trip mpg goes down very fast with the engine running at a stop light.

[insightfulone]

I'd advise just letting auto-stop kick in regardless of how short the stop. As you decelerate the gas is already shut off to the engine, so you are only extending how long it is stopped by letting it spin down. The amount of battery charge used to restart is small in comparison to the amount it will use in electric assist as you accelerate away from the stop. You'll get a few seconds more engine off time at every stop if you count the time to decelerate from 9 mph, instead of forcing it to run at 9 mph a below. All that shifting is likely to cause more wear on the CVT than allowing the car do what it was designed to do. My advice is to relax and enjoy the auto-stop, its one of the fun parts of a hybrid

[mfedorov]

I tell people that the engine shutting off when you stop is the "cutting edge of golf cart technology"

[kjanracing]

The programming in the IMA system won't let the battery get so low that it wouldn't restart the engine. If the charge got that low, you wouldn't get auto stop. There are times I do as you do and don't let the car idle stop just so the drive is smoother, like in parking lots and lost of close stop signs.