I know there is an Auto Recirculate setting on my A/C (not sure if that is true only for auto a/c or not). I understand that, with that setting activated, the ventilation system is supposed to detect pollutants in the air and automatically switch to recirculate if the level of pollutants is too high. My question is, how does it work? Is there a separate sensor just for that purpose, or does it feed off some other system, such as air intake for the fuel injection system? What does it actually sense (CO2, CO, etc.) and how (chemical, particle, etc.)? Obviously, it didn't smell the garbage truck I was behind today. Yuck.

 

Good question, I'm curious about this myself.

 

I'd be interested to know as well.

 

I believe those do NOT work on smells or odors like the garbage truck.

The sensor detects particulate matter in the air and the system closes the vents and works on recirculated air.

So if you are going through smoke, dust, etc., the sensor would detect the micro-sized particles and shut the MINI closed from the harmful environment.

Of course, the solution for the garbage truck is to manually activate the recirculate button.

 

I doubt it's that sophisticated. Recirculate does just that, it just cools the cabin air so the system doesn't have to cool the 112 degree air in AZ for instance. If the snowflake is lit all air is filtered and cooled before coming in (even if it's cold outside and it's being heated after it's cooled). There've been some burns (scheduled) around here and I can't smell smoke in my car.

 

That's right. I doubt that on a MINI that the "particulate sensor" is all that sophisticated if it works at all. Better to manually hit the recirculate button that simply closes the vent doors.

The only sensor that I expect to work OK is the outside temp thermometer and that's only because the concept has been around for hundreds of years and it's fairly simple, as long as the manufacturer has placed it properly on the car.

Other than that I don't expect much from a $30,000 car.

 

my wife has a hyundai tucson with that feature...
the dealer said it picks up on CO. So far I've noticed it kick over to recirculate with things like heavy exhaust and smoke...but not with dust from a dirt road.

I dunno if the one on the mini is the same or not (plus i dont have mine yet ). works pretty well in the (~$20K)hyundai though.

 

I dunno what the MINI uses, could be the same as your Hyundai, which I assume is some sort of infrared gas sensor.

AFAIK, the only carbon monxide sensors that can be put into a car [or the home] rely on now-very-cheap infrared technology that measure parts per million in the air [particulate smaller than a new born gnat's small toe.]

In any event, dunno enough about this or the MINI to chime in further. I'll go back to my cave.

 

My BMW/ MINI shop here in Germany said it monitors the air quality when the air reaches a level not healthy, it closes recirculates and cleans the air. I dont have any reason not to believe them, Why wouldnt it be this sophisticated? Its a Car designed by BMW and Germans, its not a ford or GM product.

 

Yes, this is what it does. My question is how? As for those who opined it can't work well on such an allegedly cheap car, could one also make that assumption about the air bags, traction control, rain sensing wipers, etc??

 

You're $3.50 and a trip to Taco Bell away from testing that theory.

 

My SA at Krauth BMW/MINI in Heidelberg Germany says pretty much what you and me think, the how is a electronic nose of sorts. Its a device which monitors the air quality IN the CABIN constantly working (when activated). Its like a constant sentry patroling for bad partriculates. You can buy air quality monitors over the counter so this type of device is really common.
Its just a sensor with relays thats all.
I have to disagree that the MINI is a cheap car. A cheap car is a ford escort, chevy midsize, Hyandia (spelling) and so on. I dont consider a 30 G car cheap. Heck even a base at 20 G isnt cheap. As a MINI its a Bargin but everyone I meet who salivates on my car cannot get over its price tag. They drive ho Hum American sedans mind you.

 

My testing is done on the Autobahn, besides the redlights and sirens go off if I attempt piloting near a Taco Bell. The filter is strong, but the force is even stronger at TB

 

is this on only on MINIs with auto climate control or on the manual one as well? i have the manual climate control and mine also has a recirculate button/option.

 

I have a manual AC. When I go through cow country on Hwy 15 I extend my arm and push the recirculated air button. Presto! No nasty odors!
I assume it shuts off access to outer air flow and redirects it somehow.

 

Not the same thing that they are talking about. Your recirculate button simply mechanically shuts the vents. Don't press the button, the vents don't get closed.

As for the sensor technology, it's pretty refined now, so much so that a carbon monoxide sensor for the house can be had for less than $20 retail.

On the MINIs that do have the sensor technology, I don't know what the MINI uses, infrared sensor, something else, I dunno.

 

It was I who alluded that a $30,000 car cannot have too sophisticated optional electronic sensing equipment. Truth be told, in today's times, $25k to $30k is not that much for a car. Not when mid-range cars are going for $40,000++

I have heard complaints thorough NAM that the MINI's climate control system does not work well. I have the climate control option but have not tested it to say one way or another.

Guess if people who have this sensing feature can post their experience that would be helpful in determining the accuracy and functionality of the option.

 

My wild *** guess would have been infrared sensor given the reports of it not activating for smells all that well. It seems like it may need to detect a sizable particulate to activate.

Also, my MA indicated it was good to have the "Auto" mode turned on because it would also help regulate fogging on the interior glass surfaces during inclement weather by automatically opening/closing vents to recirculate (or not) as needed. I've seen no evidence it actually does this except to note that my windows have never fogged up this summer here in Phoenix.

 

My Audi has a similar design, I can't say as I've even noticed it so it must work!

It seems tho that for this system to work well, you need a clean cabin filter.

I also think that those who are complaining about the auto A/C are complaining about the A/C's overall efficacy, not just this feature. I know in hot humid climates like where I live here in the midwest, it's borderline at keeping the car cool and in the winter it seems to go overboard on warming the car up, practically running me out of the car before it backs off and then going too cool before heating up again. Eventually it evens out, but by then my 20 mile commute is done!

As to the window fogging issue, in "Auto' mode it runs the A/C compressor providing much drier air, which will quickly clear the windows even when it's not hot enough to need the A/C on, it just blends heat in too so it won't be cold.

 

From the 07 manual. So far the filter in the air system has removed every outside smell I've encountered. Including driving by a dairy and a larger cattle company. Normally both of those give off a super nice aroma! Couldn't smell them at all, without even using the recirculate function.

 

I'm assuming the question is only about the auto-recirc feature, which as far as I know is only available with the auto-A/C option. If you have manual A/C you don't have the feature.

Still no really convincing ideas as to what the sensor really is, which is what I'd like to know. I do know it works wel most of the time, I'm quite sensitive to exhaust gasses and would run the A/C in recirc mode constantly in our old Civic. With the R50/R53 the particulate filter and carbon filter is pretty good but I'd still have to turn on recirc quite often. With the R56 auto-recirc, its quite rare I have to turn on recirc.

 

I guess it could just toggle on 70% of the time and off for 30% using a timer. Then they could claim a 70% reduction in particulate intake?

I know I can still smell cigarette smoke from a vehicle ahead, when the Auto-R is on, and cigarette smoke has pretty large particulate matter.

 

I've got an '04 MCS w/ auto a/c. I've noticed on hot days, if I've got it on "auto" mode - the little recirculate light will turn on and off on its own.

I just assumed that it sensed the interior temperature and decided that it could cool down the interior in recirc mode. Once the interior gets cool enough, it goes back to fresh air mode.

On a side note, I love the cabin filter! Any time I get stuck in a smelly area - all it takes is a push of the recirc button, and the smell goes away. Love it!