Exactly how do the adaptive headlights work?

[twelveup]

So far I can tell that both the inner and outer headlights move. I can also figure out that the outer lamps are both low and high beams. So are the inner lamps only for turning? Exactly when do they come on and for how long? Does anyone have a really good handle on this? Thanks!

[Yearofthe1]

Have someone sit in the car and turn the steering wheel left and right. You'll get all the answers you need.

But if you don't want to do that, only the outer lamps move. The inner ones light up on the side of the turn only, i.e. left inner lamp for left turn, right inner lamp right turn.

[Bavarian MW]

Originally Posted by twelveup

So far I can tell that both the inner and outer headlights move. I can also figure out that the outer lamps are both low and high beams. So are the inner lamps only for turning? Exactly when do they come on and for how long? Does anyone have a really good handle on this? Thanks!

Hmm, I am really just a lurker over here with a low post count (+1), BUT I know people will really slam you for asking questions
without searching first. I happen to know the adaptive headlights, angel eyes, cornering lights, etc. have been discussed many times before.

I am not the type of person to bash you for not searching, but wanted to warn you before someone else did. :wink:

[ichiban]

^ lol, well also when u reverse, both inner lights come on.

[1ToBeOn2Wheels]

:reposthorse:

[BMWTT135i]

repost!

BTW here is a video of them at work:

[MatthewDFW]

They also move up and down (e.g., when cresting a hill or leveling out at the bottom of a down-grade). Engineers at BMW worked hard to emulate the natural movements of human eyes, tracking slightly ahead of curves and elevations. The most commonly-cited example is how you would look a little ahead of the next curve or climb on a roller-coaster, instead of straight ahead.

[jeremyc74]

Originally Posted by BMWTT135i

repost!

BTW here is a video of them at work:

Here's a better version of the same video. Youtube squashes stuff that was shot in 16:9 and it makes it look strange.

[Yearofthe1]

Originally Posted by MatthewDFW

They also move up and down (e.g., when cresting a hill or leveling out at the bottom of a down-grade). Engineers at BMW worked hard to emulate the natural movements of human eyes, tracking slightly ahead of curves and elevations. The most commonly-cited example is how you would look a little ahead of the next curve or climb on a roller-coaster, instead of straight ahead.

Are you sure about this one? I'm not saying I don't believe you, but I've yet to notice this in action. Where have you read this and what do I need to do to see it working.

Wouldn't the car need nome sort of forward-looking radar in order to make this work? How does it know you're coming to a crest or a dip? I can imagine some kind of accelerometer could do the trick, although you'd be deep into the dip or crest before the headlights responded, and this wouldn't offer much advantage.

[MikeCCrutchfield]

Originally Posted by Yearofthe1

Are you sure about this one? I'm not saying I don't believe you, but I've yet to notice this in action. Where have you read this and what do I need to do to see it working.

Wouldn't the car need nome sort of forward-looking radar in order to make this work? How does it know you're coming to a crest or a dip? I can imagine some kind of accelerometer could do the trick, although you'd be deep into the dip or crest before the headlights responded, and this wouldn't offer much advantage.

Actually, as the front suspension extends at the crest of the hill (but the back stays firm) until it crests, the headlights will dip a little bit because it will act like the car has a heavy load in back. There are two sensors, on on the front suspension, one one the back, and that is how it levels the headlights.

[jeremyc74]

Originally Posted by Yearofthe1

Are you sure about this one? I'm not saying I don't believe you, but I've yet to notice this in action. Where have you read this and what do I need to do to see it working.

Wouldn't the car need nome sort of forward-looking radar in order to make this work? How does it know you're coming to a crest or a dip? I can imagine some kind of accelerometer could do the trick, although you'd be deep into the dip or crest before the headlights responded, and this wouldn't offer much advantage.

It's more for keeping the car level under braking than for cresting hills.
You can see this in action by going out on a dark road, putting the headlights on high (it works on low but it's not as obvious), and hitting the brakes hard then let off. You'll see that the headlights correct for the angle of the car under braking instead of just dipping like normal lights.

You can nail the throttle at low speeds and get the same response as the nose raises up. It's pretty cool.

[Yearofthe1]

Originally Posted by MikeCCrutchfield

Actually, as the front suspension extends at the crest of the hill (but the back stays firm) until it crests, the headlights will dip a little bit because it will act like the car has a heavy load in back. There are two sensors, on on the front suspension, one one the back, and that is how it levels the headlights.

Originally Posted by jeremyc74

It's more for keeping the car level under braking than for cresting hills.
You can see this in action by going out on a dark road, putting the headlights on high (it works on low but it's not as obvious), and hitting the brakes hard then let off. You'll see that the headlights correct for the angle of the car under braking instead of just dipping like normal lights.

You can nail the throttle at low speeds and get the same response as the nose raises up. It's pretty cool.

Thanks guys. I was wondering how this worked and a set of suspension sensors does make perfect sense. I'll try this the next dark lonely night I'm on the road. I read somewhere else that you can compare the effect of this vertical leveling by switching from the adaptive setting to the manual setting and seeing the difference.

[jeremyc74]

Originally Posted by Yearofthe1

Thanks guys. I was wondering how this worked and a set of suspension sensors does make perfect sense. I'll try this the next dark lonely night I'm on the road. I read somewhere else that you can compare the effect of this vertical leveling by switching from the adaptive setting to the manual setting and seeing the difference.

You can also see them go up and down when you first start the car up if the switch is in the Auto setting.

I discovered the suspension sensors while I was under the car doing some work, and it wasn't until later that night that I figured out what they were for. Up until then I thought they were just using a level sensor to make it work, but the suspension travel sensors make much more sense.

I've always wondered if putting lowering springs on the car changes the headlight angle. It seems like it would if the front is dropped more than the rear.

[twelveup]

To all you forum Nazis, if you don't want to read the post, then don't read the post. I DID search for a clear answer to this question under several different search terms and found nothing that was clear and cogent about exactly what was going on up in the front of the car as I drive.
To those who provided an actual answer, thanks a lot. Much appreciated! It is a really amazing system. If they were going for an approximation of what the human eye does, they're pretty close to the mark. Those lights are always where you want them.

[WAY]

Does anyone know if the adaptive headlight stop being adaptive at a certain speed, or does it work no matter what speed you are travelling? Thanks.

[ZIPNBYE]

Originally Posted by WAY

Does anyone know if the adaptive headlight stop being adaptive at a certain speed, or does it work no matter what speed you are travelling? Thanks.

If they're on, they're on, regardless of speed. If you've got the headlight switch set to ON, but not the A-ON, then they won't work, again, regardless of speed.

Recognize that at higher speeds, you're likely making smaller steering inputs (or the road's a lot straigher, hence your higher speed) and their movements may not be so evident.

[Lester]

Here is what the manual says on the topic.

[jeremyc74]

Originally Posted by WAY

Does anyone know if the adaptive headlight stop being adaptive at a certain speed, or does it work no matter what speed you are travelling? Thanks.

I can verify that they still do their thing at just over 100MPH. Beyond that I'm not sure, I've never hit a significant curve any faster than that at night.

In the video I have posted you can see that I was nearing 80MPH in certain sections, and they were still moving around.

[MZWIE]

For the most part I like them. However, when doing spirited driving on a twisty road it is very disconcerting. I instinctively tend to follow the lights as they dance back and forth and loose sight of the road ahead.

So in these cases I turn off the adaptive part and go to normal.