Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Normal Operating Sounds

tesla.com

Post reply on HN
Print view View original

21–30 of 273 posts

Re: Normal Operating Sounds

#21

Post by dmix »

jacquesm wrote: post #16
Waterluvian wrote: post #8

Earlier quoted context omitted.

I always thought about this growing up. How the engine’s heat is used directly to heat the cabin and there is no heater. Also my gaming PC in the winter. It feels like free compute given I’m heating anyways.

A gasoline based ICE is so incredibly inefficient it needs to shed heat or it would melt down. It makes more heat than that it makes motive power (the thing it is designed to do...). A 50 KW engine makes 200 KW(!!) of heat (at full throttle). Most of that heat energy exits the system through the exhaust gases but there is plenty that gets stuck in the body of the engine and you need to remove it from there somehow be…

I always wonder how you know so much about so many topics to make quality comments on a wide variety of topics on HN. Truly a jack of all trades.

Maybe it's like how I spend so much time reading random Wikipedia articles on topics because I need to know how everything works.

Re: Normal Operating Sounds

#22

Post by Kirby64 »

jacquesm wrote: post #17
AYBABTME wrote: post #14

The loud "pops" at superchargers and when driving after supercharging surprised me for a while. I would stop to look under the car if I had hit something. The pops while charging are sort of self-explanatory, but those while driving took me a while to associate back to the prior supercharging. Basically, changes in temperatures are causing the pops. It's kind of weird and slightly annoying. Sometimes it happens for q…

What is the cause? Thermal expansion? I have a room in my attic that can make really loud bangs on hot summer nights (enough to scare the crap out of me when I am concentrating on something and do not expect them) when it contracts again after a day in the heat. The root cause there is stick slip: the thing doesn't move for a long time due to its weight so tension builds up and then suddenly it will shift a little an…

Similar mechanism as your attic noises. There's a giant metal plate on the bottom of the thing, so all the heat generated while it's supercharging (in a very cold environment) causes that 'snap' which makes a loud noise. Same thing happens if you've ever heated up a thin metal baking sheet. It'll 'snap' from one position to another and make a horrible racket.

Same thing apparently happens if you are heavy on regenerative braking when descending a mountain pass. Cold air, plus 50kW+ of regen braking is similar to just supercharging the car.

Re: Normal Operating Sounds

#23

Post by afavour »

Waterluvian wrote: post #8
bigyikes wrote: post #7

This one is pretty cool and definitely surprised me. > Motor Humming or Whirring when Navigating to a Supercharger … > In some circumstances (such as cold weather), it is normal for the motor(s) and components to make noise, such as humming or whirring as it generates heat to warm the Battery. Super cool that the motors can be used for things other than moving the vehicle. It reminds me of how ESCs for RC vehicles us…

I always thought about this growing up. How the engine’s heat is used directly to heat the cabin and there is no heater. Also my gaming PC in the winter. It feels like free compute given I’m heating anyways.

Unfortunately I have a vivid memory of the opposite: driving an extremely decrepit old car through the south in July, had to crank the heat to max to try to direct the heat away from the engine. No AC in the car, naturally.

Re: Normal Operating Sounds

#24

Post by jacquesm »

Kirby64 wrote: post #22
jacquesm wrote: post #17

Earlier quoted context omitted.

What is the cause? Thermal expansion? I have a room in my attic that can make really loud bangs on hot summer nights (enough to scare the crap out of me when I am concentrating on something and do not expect them) when it contracts again after a day in the heat. The root cause there is stick slip: the thing doesn't move for a long time due to its weight so tension builds up and then suddenly it will shift a little an…

Similar mechanism as your attic noises. There's a giant metal plate on the bottom of the thing, so all the heat generated while it's supercharging (in a very cold environment) causes that 'snap' which makes a loud noise. Same thing happens if you've ever heated up a thin metal baking sheet. It'll 'snap' from one position to another and make a horrible racket. Same thing apparently happens if you are heavy on regenera…

Oh, that last one is an interesting one.

Re: Normal Operating Sounds

#25

Post by jacquesm »

dmix wrote: post #21
jacquesm wrote: post #16

Earlier quoted context omitted.

A gasoline based ICE is so incredibly inefficient it needs to shed heat or it would melt down. It makes more heat than that it makes motive power (the thing it is designed to do...). A 50 KW engine makes 200 KW(!!) of heat (at full throttle). Most of that heat energy exits the system through the exhaust gases but there is plenty that gets stuck in the body of the engine and you need to remove it from there somehow be…

I always wonder how you know so much about so many topics to make quality comments on a wide variety of topics on HN. Truly a jack of all trades. Maybe it's like how I spend so much time reading random Wikipedia articles on topics because I need to know how everything works.

Hm... too many projects :)

And that list is only getting longer, I think I'll pass it on to my kids.

Right now (and for the past couple of years) it has been mostly music but also still some more interesting tools to play with. Currently making a set of super realistic traffic lights for my youngest including pedestrian crossing and automatic cycle influencing (road coil pickup to detect car presence in front of the lights) for his model cars. Green wave, the works.

I've mostly stopped writing up the projects, but still have a bunch of posts pickled that I probably should finish. Most recent software bit: ear training module for pianojacq.com is work in progress (press low 'A' on an 88 key keyboard to enable the secret menu that will enable the ear trainer, it is not quite ready for mass consumption yet but it is getting there).

Re: Normal Operating Sounds

#28

Post by dralley »

bigyikes wrote: post #7

This one is pretty cool and definitely surprised me. > Motor Humming or Whirring when Navigating to a Supercharger … > In some circumstances (such as cold weather), it is normal for the motor(s) and components to make noise, such as humming or whirring as it generates heat to warm the Battery. Super cool that the motors can be used for things other than moving the vehicle. It reminds me of how ESCs for RC vehicles us…

My understanding is that high-end residential heat pumps (e.g. Mitsubishi HyperHeat) will do this at lower temperatures as well. If the temp drops into the zone where the heat pump starts losing effectiveness (which on such systems is still pretty low, supposedly mine provides the full heat rating down to around 0F), they can run the blower motor in a less efficient regime to supplement the heat pump with a bit of resistance heating, without needing to fall back to a true "auxillary" heat source like heat strips or a furnace. That can extend the effective range down to a few degrees below zero (Fahrenheit).

Since I live in the southeast, that's more than good enough to skip installing any auxillary heat source in the first place.

Re: Normal Operating Sounds

#29

Post by dclowd9901 »

Racing0461 wrote: post #9

Feels like a good opportunity to in addition to having the normal system diagnosis, have a process that listens to the sound the car makes and recommend bringing it into the shop if the sound sounds weird or off.

This really is a tremendous idea and if vehicle software engineers were better they might actually be able to do it.
Post reply on HN