Vacuum Switches

[FutureBoy]

So....

I was watching a YouTube video about a car from the 80's and they were describing how to turn on AWD. The video had the following quote.

When you want to go into all-wheel drive, you hit the AWD switch on the instrument panel. A relay module activates a vacuum switch. A transfer case, which replaces the pan of the FLC automatic transaxle, takes power from the transaxle's final gear. Gears are engaged to turn the driveshaft, which sends power back to a limited-slip differential, which turns the axles to drive the rear wheels.

With EV's it seems this whole system would be built with far fewer parts. But what caught my attention was the vacuum switch. I know car engines and motorbikes use vacuum switches. It seems like really old tech on the order of leather belt drives. And I was immediately thinking of Elon's quote: "The best part is no part." Like why have an electronic switch signal a relay that switches a vacuum switch that then makes a mechanical change to the driveshaft? Seems way overly complicated. I get it. It was the 80's and we all thought our technology was super great.

Now though I have to wonder. Other than cars (or I suppose any system powered by a hydrocarbon engine) is there anywhere else we regularly use vacuum switches? And other than that it was the tech available at the time of the combustion engine development, is there a reason to keep using vacuum switches in cars?

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[Ogre]

No.

There is no vacuum system on a Tesla and never will be.

Well maybe not never. I'm not sure about how trailer brake systems work.

Everything on the Tesla is electric.

 

[android04]

No.

There is no vacuum system on a Tesla and never will be.

Well maybe not never. I'm not sure about how trailer brake systems work.

Everything on the Tesla is electric.

Trailer brakes are electric or hydraulic (surge brakes activated by the pressure on the tongue between vehicle and trailer). Semi trailers have air brakes (need air pressure to deactivate the brakes).

 

[Jhodgesatmb]

No.

There is no vacuum system on a Tesla and never will be.

Well maybe not never. I'm not sure about how trailer brake systems work.

Everything on the Tesla is electric.

I get the point but not everything on a Tesla is electric. There are pneumatics and hydraulics and mechanical (transmissions, linkages, etc.). We can be pretty certain that the AWS will be electric.

 

[CyberGus]

I know some ICE vehicles converted to EV had to install an electric vacuum pump lol

 

[Ogre]

I get the point but not everything on a Tesla is electric. There are pneumatics and hydraulics and mechanical (transmissions, linkages, etc.). We can be pretty certain that the AWS will be electric.

Teslas are single speed per axel. There is gearing by no gear shifting. If there is any thing pneumatic I have no idea what it might be. There are electrical actuators for the doors. Other than that not a lot of switches.

I guess brakes and steering linkages?

 

[Crissa]

Brakes are pneumatic hydraulic, generally.

-Crissa

Edit: Fixed

 

[Newton]

by pneumatic, you mean hydraulic?

 

[Crissa]

by pneumatic, you mean hydraulic?

Gosh dangit, yes. I don't even remember typing that! x-x

If anyone ever wonders why my posts always have edits... I try to catch these things before others see them.

-Crissa

 

[Newton]

Gosh dangit, yes. I don't even remember typing that! x-x

If anyone ever wonders why my posts always have edits... I try to catch these things before others see them.

-Crissa

Same, same

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