Hybrid Engine Revving When Going Downhill

[fbov]

On earlier hybrids, you had an option in the settings menu for "Hill Assist" which would use the engine in a manner very much like a Jake brake. It's not something I'd call "normal," rather "as designed" or perhaps "special" since you need a really long steep hill to activate it in mine.

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[BILLNOROVILLE]

My 2016 Volt had Mountain Mode. I captured more electricity for the batteries and had more battery reserve for longer power bursts. Actually quite good for slowing down and power out of winding curves one after another. I often ended the section of curves miles later wire more battery power than when I started. Good feature.

 

[Red Ryder]

That's the regen brake trying to control your descent. It goes absolutely nuts when you go down a steep hill for a long time. First time I heard it I was sure my transmission was about to explode.

Thanks! I bet that's exactly what it was.

Sounds like a Black Mountain downhill adventure.

That run could charge a dead Tesla. I've seen quite a few overheated brakes at the bottom of that hill, including some vehicle fires.

 

[dogie rider]

Sounds like a Black Mountain downhill adventure.

That run could charge a dead Tesla. I've seen quite a few overheated brakes at the bottom of that hill, including some vehicle fires.

It was weekend trip to Asheville. The eastbound run keeps your attention.

 

[Adospeed]

I recently took a trip to the NC mountains. On my way home I was on a long downhill run, with my cruise control on, when I had a couple of episodes of my engine revving out of control. Anybody else experienced this? I have wondered if it was because I had the cruise control on.

I did have this happen on an extended downhill mountain road. I was like WTF is going on???!! I got on the gas just to add some variable or input, and that made it chill out. But like you, what I heard was "high revving" sound. I haven't done that same hill since then, so it has not occurred again since.

 

[ScorpioST]

Just did some big mountain descents here in British Columbia and experienced what I would call extreme dangerous sounding over-rev. Was expecting pistons or transmission parts to start blowing out onto the highway. I cannot see how this would be considered normal behavior for a vehicle. Heavy brake or stabbing the accelerator gets it somewhat back to normal sounding, but me thinks a reprogramming is needed.

Maybe I just have old outdated beliefs on what a modern engine is capable of , especially if there's no fuel burning and it's just compression. But it don't sound right

 

[Gunnar88]

I wonder if consuming more electricity would effect this, like running the seat heaters and the ac?

 

[GPSMan]

Seat heaters, not.
Wattage is very low. Like 15 watts.
You can turn on air conditioning and all lamps. That would add up to maybe 1500 watts. But that's 2 brake horsepower.

The regen going down a hill, if the needle is all the way to maximum is 32,000 watts. There's not much you can do to "burn off" that much wattage when going down hill.

That said, the truck won't do anything to harm itself. It is so remarkably noisy during engine brake, compared to how quiet it is the rest of the time.

100% normal.
100% programmed correctly.
100% safe, just unusual.

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