ACC Surges on Hills

[TimothyN]

There is quite a long, quite steep, hill from Westerham to Biggin Hill, and if I use ACC to climb it, it surges so badly as to be quite unpleasant.

The Audi managed it with no problem.

Have others discovered this?

 

[decrep]

Very coarse control of the accelerator maybe?
Car slows down, ACC over corrects, goes too fast, ACC over corrects, goes too slow!
I never use it on principle so I'm only guessing.

 

[Ian Key]

Which driving mode are you in and which regen level?

 

[TimothyN]

Normal and OPD.

 

[Ian Key]

Normal and OPD.

Hmmm. I know there are reports of OPD causing the car to reverse when stopping downhill I wonder if it's causing the surging you're experiencing.

I haven't tried ACC up a steep hill like you describe yet myself but I'll have a go later

 

[Alb]

I've noticed this and the hill doesn't have to be that steep.
It seems to modulate power rather than feed it progressively. Road speed and the driving experience is still smooth but it seems like an inefficient way of controlling the motor.

 

[decrep]

Way back in the day, I think this is what we called "hunting". The comparater runs faster than the adjustment mechanism. You just need to detune the comparator. Back in the day there would be a potentiometer to adjust the gain. But probably done with software now, Could an update fix it? Who knows.

 

[Ian Key]

Just tried it up a 30 mph hill in normal without OPD and yes it did surge. I'll try it in comfort mode next to see if that makes any difference.

 

[DBedford]

There is quite a long, quite steep, hill from Westerham to Biggin Hill, and if I use ACC to climb it, it surges so badly as to be quite unpleasant.

The Audi managed it with no problem.

Have others discovered this?

The MG user manual does warn about ACC in hills, see page 213 of etc user manual.

And as MG's are not in the same class as Audi, really hard to compare the two.