Hacker News Reader

Comment by pmontra | Hacker News Reader

> the EPA is mandating that the engine stop while the vehicle is stationary

How could they use AC and heating with traditional cars, when they had to stay stationary for a long time in summer or winter?

View on HN

I'm not sure exactly what the rule says. I've heard stories of people buying a modern SUV, and needing to push a button on every trip, to disable the start/stop feature. I've also heard of people making a little motorized arm that pushes the button automatically.

Edit: It's not strictly mandatory. See page 3 of https://www.govinfo.gov/content/pkg/CFR-2014-title40-vol19/p...

> It's not strictly mandatory.

My understanding is that if the automaker uses it during the EPA fuel economy test, it must be enabled every time the car starts. If not, the automaker can choose to have it remember your preferences.

My pickup engine stops when I come to a stop, usually, but after some time will start up again if power is needed to continue to run the AC and electronics.

Warming up the truck in the winter isn’t an issue, it starts and runs like normal.

Heat generally continues to work for quite a while, because there's quite a lot of thermal mass involved. As for the AC, some vehicles have reserve pressure canister that can keep it going for a little bit before they have to cycle back on.

I'm only assuming that both of my brand new cars are EPA compliant (they may not be) but they'll just turn back on if it's been long enough to get too cold or warm.

You get like 30 seconds of cold air before the compressor being off is evident. A lot of people turn this “feature” off if they can.

Reply on news.ycombinator.com