[DEinspanjer]

Okay.. I'm a Model S owner and I love Tesla and I chuckled at the whole Insane mode and gave a bit of an amused snort at Ludicrous mode.

This, however, really makes me wonder WTH is going on there:

HEPA Air Filters "There are three modes: circulate with outside air, re-circulate inside air and a bioweapon defense mode that creates positive pressure inside the cabin to protect occupants."

EDIT: Very fair points about driving by skunks or nasty smells. The naming is what gets me though. If it was called Noxious Smell Defense Mode or something, that would make perfect sense. Looking at Wikipedia, a "medical grade HEPA filter" can filter out 99.97% of particles at least 0.3 micrometers in diameter. Dunno if the Tesla filters are also using UV irradiation, and I also couldn't find any documentation of the particulate size of skunk odor, so it will be interesting to see documentation on what exactly it can filter out.

EDIT2: Watched a bit of the intro event video. Looks like it has a specific set of activated charcoal filters for sulfur type particulates, so certainly seems like it could be a skunk odor killer. :)

[trishume]

Yah I found that a bit paranoid. Probably what happened though is that the system is controlled by a microcontroller and it took 3 minutes for some programmer to add that feature for fun, and then some marketer thought they would throw it in and make it real.

[chillydawg]

Except how is it generating positive internal pressure without storing compressed air somewhere?

[BYWallace]

I believe it's because pumping filtered air from the outside faster than it can escape from the cabin creates the positive internal pressure.

[chiph]

Modern cars have a cabin air outlet. It's usually hidden in the trunk or the back of the cab (on trucks), and vents somewhere like behind the plastic bumper. There are rubber flaps on them to ensure one-way air travel and keep water out. Perhaps Tesla's has a motor on theirs to keep it closed against the increased cabin pressure.

From a 2015 Honda Accord, it's #35: http://imgur.com/QsJexwI

Side-effect of this part - manufacturers tune them so that the doors produce a solid sound when closed.

[darkmighty]

Just by pumping air inside through filters a positive internal pressure is automatically created. How much pressure will be created is proportional to the pump's flow rate and inversely proportional to the car leakage constant ( I think it's something like leakage ~ k * P.I.P., which would make P.I.P. ~ pump flow/k ), but some positive internal pressure is a given even with those outlets.

[DannoHung]

How is that a bioweapon defense then? Do HEPA filters work against bioweapons?

[wlesieutre]

Probably depends on the bioweapon. For instance, I'd expect it to be effective against anthrax spores, which was the most recent bioweapons scare we had.

You're still using outside air, but by maintaining positive pressure you ensure that it's only coming in through the filter, rather than a mix of air intake and leaky joints.

This will be used 99% for skunks.

[varjag]

Not sure about particular type of filter, but CBRN countermeasures found on tanks, APCs and such are also basically air filtration with positive internal pressure.

[giarc]

I think that is tongue in cheek.

[Someone1234]

It absolutely is, but that doesn't mean it wouldn't work in principle.

A HEPA filter is used in a lot of labs where biological substances are handled, even potentially hazardous ones. It should filter many types of biological agent out of the incoming air, and the positive pressure will keep such things entering other ways.

I think the reason they put it in is so people would talk about it and, look, we are. It is a marketing gimmick that likely doesn't require any additional hardware in the car (the air pump and HEPA filter are already in it, this just turns the pump up and adds a new dash button).

I'll give Tesla the nod for one thing: They sure know how to market. Between the wing doors, the bio-protection mode (which will be on the nightly news), and insane mode they're very savvy.

[psychic_friends]

Pretty sure this is the real reason Musk wanted a superior air filter - playa dust storm protection: https://farm2.staticflickr.com/1057/1338020035_678b988a6e_o....

[bendykstra]

Fans, which force air through the filters into the cabin.

[perlgeek]

It could heat the air on the inside, so that it expands :-)

[tantalor]

This kills the passenger.

[yk]

They are probably storing compressed air in the cabin. You start the bioweapon-defense-mode, the fan raises the pressure in the cabin ( that uses outside air) and then shuts off. (Or they store a little bit of air somewhere, perhaps for the breaks, and use that.)

[seanmcdirmid]

They are aiming this car at Chinese buyers I bet. The last mode would definitely get lots of use in Beijing.

[agumonkey]

A "green" car feeding on polluted markets. Touching.

[myko]

It makes sense to me to target the areas that are worse off with regards to pollution first with green technology. Am I missing something?

[seanmcdirmid]

Exactly. China desperately needs green technologies because their pollution problem is so bad and noticeable, so they are focusing more on them.

Too bad the Tesla would probably be charged from a coal plant somewhere in Hebei with bad pollution controls.

[agumonkey]

No, of course it is the premise of business, that's why I said 'feeding' it would be almost dependent on pollution then.

[TrevorJ]

Isn't that how it should work?

[ctdonath]

Sounds silly to most, but there are situations where you don't want unfiltered outside air leaking in. If "seriously filtered cabin air supply" is relatively easy to add, there's no downside to adding it. Here around Atlanta, the pollen count can exceed 5000 for weeks (and 500 is considered "extremely high"); a good filter would be dearly appreciated by many. For an interesting comparison re: "bioweapon", consider the armored luxury car market with product features such as http://www.caratsecurity.com/Products/sedans-and-SUVs.php

[raisedbyninjas]

It's not silly at all. I wish I had this everyday that I'm sitting in traffic. My car has multiple climate control modes that default with the vent open. Some heater modes override the vent button and force me to use outside air. I actually know what the outside humidity is and the amount of car exhaust I want to suffer. But apparently that doesn't matter to Mazda.

[wang_li]

If you don't have a steady flow of outside air into your car's cabin, you will soon die.

[ctdonath]

The point is there's a difference between ambient outside air leaking into the car like a sieve, vs completely sealed with air supplied via biohazard rated filtration. Also, you'd be surprised how long you can function fine in a sealed box the size of a car cab.

If you haven't seen waves of pollen wafting thru the air for miles, like we regularly see near Atlanta, you may not grasp the interest.

[bryanlarsen]

"bioweapon defense mode" is probably useful for people with allergies.

[Raphmedia]

This.

I would buy this car for this feature alone. Allergies are the bane of my existence. I would love to have a car that is an allergy free zone. Sometimes, I drive through big farm areas... and I want to die.

[Amorymeltzer]

HEPA filters in general are. This will be very welcome.

[liotier]

> bioweapon defense mode that creates positive pressure inside the cabin to protect occupants

Ever drove past a skunk corpse ? Only happened to me a few times when I traveled in the USA - still have PTSD...

[teekert]

" To qualify as HEPA by US government standards, an air filter must remove (from the air that passes through) 99.97% of particles that have a size of 0.3 µm."

That means bacteria (1-10 µm) and spores (~1 µm) but not virusses (~ 100 nm +/- a lot) and certainly not molecules emitted by a skunk corpse.

[warfangle]

Its activated charcoal filter has the primary layer, a secondary layer that filters sulfur gases, and a tertiary layer that filters alkaline gases.

Skunk spray is made primarily of thiols and their acetate derivatives. Thiols (the main ugly smelling ones are both thiols) are organosulfur compounds, and would be filtered by the secondary chemical filter.

The gases that make the decaying corpse smell are acidic (AFAIK), so would be filtered by the tertiary layer.

[teekert]

Ah, I didn't catch that, good comment.

[michaelmior]

Not an uncommon occurrence in rural Canada. It's not particularly pleasant, but you get used to it.

[vcarl]

The real veterans know to open the windows as soon as you get a whiff.

[roc]

Recirculating cabin air is plenty for skunk. Even economy American cars -- that no-one would confuse with exceptional engineering -- do just fine keeping the stink out.

[JoeAltmaier]

My old GMC Jimmy had no recirculate setting. Incredible. We live off gravel roads. When following another car, I had to just stop and wait a minute for the air to clear, else I'd be choked by lime dust in seconds.

[joezydeco]

A skunk sprayed the neighbor's dog in my front yard the other night. You got off light.

[mavrc]

In the country, this happens pretty frequently. If you think that's bad, try driving by a large dairy on a hot, still day.

[spyder]

Maybe Elon Musk is preparing it for Mars (with the positive pressure) and it will have a hidden "Launch to Mars" button :)

[tkinom]

Not Launch.

Elon's next project is a wormhole hyperloop to Mars.

[memonkey]

Full disclaimer, I work for a somewhat prestigious air filtration company.

I agree the wording is a little bit on the strange side. However, if they are saying that it's a "bioweapon defense mode" they should probably be saying that they can catch 0.03 microns as opposed to 0.3 microns. That is virus level small. There should also be several filters in there, a large particulate filter for the big stuff, an activated carbon filter for the odors, and an ultra fine particulate filter for the 0.03 kinds of small stuff.

UV ends up not being worth it because you'd have to replace the bulb almost on a monthly basis. Ionizers just make your particulates sticky, so they'd go right through the filter and stick to your clothes/seats/walls.

[DEinspanjer]

In the Launch Event video, Elon goes into more detail around the 10 minute mark.

The filtering is effective down to 0.01 microns. During testing, they were not able to detect any measurable level of spores, bacteria, or viruses in the air passing through the system.

Two separate filters, and the main filter has three levels of activated carbon. First: Universal (hydrocarbons) Second: Acidic gases (sulfur) Third: Alkaline gases (ammonia)

[kogepathic]

Okay, but let's get to the important part: can I use my Model X as a clean room?

[toomuchtodo]

Elon mentions the air is as clean as a hospital operating room. Close enough.

[ohitsdom]

> UV ends up not being worth it because you'd have to replace the bulb almost on a monthly basis.

I have a UV system on my home A/C, and the bulb usually burns out once every two years (and it's always on). I'd imagine this would be greatly extended if in place in a car when it's not always on. Am I missing something?

[votingprawn]

The effectiveness of a UV lamp decreases with age, so they can stop being effective long before they actually burn out. There should be a manufacturer rating on the lamp, which will depend on its composition and other things.

As an example the lamps I use have a rating of ~8000hrs, about a year, but to the outside observer they'll still look functional until they blow after 2-3 years.

[toomuchtodo]

Do they have UV LEDs yet?

[retbull]

I thought that turning lights on and off is most of what causes damage to them.

[mangeletti]

I don't think the goal is to provide a bio-weapon defense system (I think it's more for bad smog), but this truthfully is how you would defend against a bio-weapon in a vehicle; use the only safe air source (the HEPA filter) to pump air in at a rate that maintains positive pressure in the cabin, preventing air from leaking into the vehicle from unsafe sources (e.g., a small crack in a seal somewhere).

[enraged_camel]

During the release event last night, Elon called it a "bioweapon defense mode" as a joke and everyone laughed. I don't think they seriously mean it, but it can still be useful for people with allergies.

[NDizzle]

You can also call it "Coalinga Mode" when you are passing through Cow Hell on I5.

[AYBABTME]

To me, those names come in line with:

   - Just Read the Instructions
   - Of Course I Still Love You

...and other silly, whimsically chosen names in the tradition of Culture spaceships (from the series by Iain Banks). Perhaps they're naming their special modes in a slightly similar vein?

[astrange]

Tesla's silly naming is a little more insidious than that. They started out naming their cars S E and X, only changing E to 3 to get around a Ford trademark.

[deepGem]

HEPA is not just to avoid smells or pollen. It's the only filter that can remove PM2.5 (particulate matter < 2.5 microns in size). WHO terms them as group 1 carcinogens and in most cities including NY, Houston etc, PM2.5 levels are far beyond safety limits. It's a shame that other auto manufacturers don't include a HEPA as their cabin filter. That might be because of gasoline engine limitations.

[ebbv]

The name is obviously tongue in cheek much like Ludicrous Mode. I think it's hilarious and I hope when the Model 3 comes out I am able to get a Bioweapon Defense Mode button on mine.

[JulianMorrison]

Drive through the zombie apocalypse in comfort? Or more realistically, drive through a forest in pollen season and not get hay fever.

[chisleu]

People who shall remain nameless have been installing custom paintball gun-like devices on the undercarriages of cars with hoppers filled with pepper spray balls. Normally aimed to the rear of the car, they can be used to stop dangerous tailgaters or the like.

I'm sure there are other things in the works, so this isn't really that far fetched.

[happywolf]

The car must be reasonably air-tight by itself to make this work, and I imagine there should be a warning signal/siren to driver if someone tries to open a window when this mode is enabled.

[frrp]

> HEPA Air Filters "There are three modes: circulate with outside air, re-circulate inside air and a bioweapon defense mode that creates positive pressure inside the cabin to protect occupants." This is immensely useful in Chinese cities!

[shas3]

Well, given how common forest fires are, I think it can be useful. In the last two years, I've been through three forest-fire caused 'air quality warnings' which caused genuine discomfort in Arizona, Minnesota, and Oregon.

[beachstartup]

ever drive by a cattle feedlot, or a forest fire? that could come in handy.

[philwelch]

They wrote that feature specifically for Elon Musk. And maybe Roman Abramovich.

[benihana]

Californians and wild fires come to mind