The rise of fake engine noise • Hacker News Board

Re: The rise of fake engine noise

#31

Post by Gracana » Thu, Jan 22, 2015, 3:18 AM UTC

zyxley wrote: post #24

scroy wrote: post #15

Earlier quoted context omitted.

From what I've read, that wouldn't be relevant for an electric vehicle, since there is no transmission. Or that might only be for the Tesla.

Literally the entire reason for the transmission for a combustion engine is to make the relatively high minimum speed of an internal combustion work for lower road speeds, with the pleasant side effect of increasing torque at low speed. Electric motors have no need for one, because they have both variable speeds and generally tremendous amounts of torque to start with.

Electric motors tend to have wide useable rpm ranges, but their efficiency varies across the range, so a transmission is still useful.

Scroll 2/3 of the way down this page to see a representative brushless DC motor performance curve, for example: http://www.johnsonelectric.com/en/resources-for-engineers/au...

Re: The rise of fake engine noise

#32

Post by webwielder » Thu, Jan 22, 2015, 3:38 AM UTC

The phrase "the rise of" is really being abused these days.

Re: The rise of fake engine noise

#33

Post by yummyfajitas » Thu, Jan 22, 2015, 3:43 AM UTC

This is hardly new. In college, we had a guest lecture from a mechanical engineer at $POPULAR_MOTORCYCLE_MANUFACTURER. He described how his team cooked up a new engine design that achieved some significant performance increase over the old design. Only problem? It didn't sound like a $POPULAR_MOTORCYCLE.

The new engine was delayed for a year while they cooked up a mechanical noisemaker to adjust the sound.

Re: The rise of fake engine noise

#34

Post by mikeash » Thu, Jan 22, 2015, 3:47 AM UTC

Gracana wrote: post #31

zyxley wrote: post #24

Earlier quoted context omitted.

Literally the entire reason for the transmission for a combustion engine is to make the relatively high minimum speed of an internal combustion work for lower road speeds, with the pleasant side effect of increasing torque at low speed. Electric motors have no need for one, because they have both variable speeds and generally tremendous amounts of torque to start with.

Electric motors tend to have wide useable rpm ranges, but their efficiency varies across the range, so a transmission is still useful. Scroll 2/3 of the way down this page to see a representative brushless DC motor performance curve, for example: http://www.johnsonelectric.com/en/resources-for-engineers/au...

AC induction motors (typically what's used in electric cars) have a pretty flat efficiency curve. For example: http://powerelectronics.com/motion-systems/motors-efficiency...

There would be some minor efficiency gains from having multiple gears, but it's probably small enough that it would be hard to overcome the extra losses from having a more complex transmission.

Note that technically electric cars do have a transmission. The motor wants to spin much faster than the tires, so you want a reduction gear to let them both live in the ranges where they're happy. It's a single-gear transmission, though, on every electric car I'm aware of.

Re: The rise of fake engine noise

#35

Post by kw71 » Thu, Jan 22, 2015, 3:51 AM UTC

jrochkind1 wrote: post #2

You'd think some people would want to opt out of the fake/amplified engine noise, so they can drive in peace, listen to their stereo without interference, etc. but i guess making the amplified/fake engine noise an option would defeat the purpose.

Is this article about engine or exhaust noise?

I prefer quiet exhausts, and it's nice to hear the engine itself sometimes when I deliberately select too low a gear.

I look at loud exhausts with disdain, and think they show childishness, insecurity or narcissism.

Re: The rise of fake engine noise

#36

Post by meric » Thu, Jan 22, 2015, 3:53 AM UTC

jcromartie wrote: post #20

Noise is just wasted energy that could be doing useful work unless, of course, you actually want the noise (like in a musical instrument). This is a really weird trend.

There will be a set of circumstances where you will be resorting to beeps to alert pedestrians without engine noise.

Time spent to contemplate whether to beep or not constantly may also be wasted time.

Re: The rise of fake engine noise

#37

Post by zemvpferreira » Thu, Jan 22, 2015, 4:00 AM UTC

13 wrote: post #8

At some point the engine noise just becomes completely arbitrary. Avertisers will buy out your engine noise sounds, as you pass by in your Telsa furniture warehouse salesmen will scream from the engine compartment.

Eerily reminds me of "sales pitch", the Philip K Dick story where advertisers hijack your thoughts while you're commuting: http://en.wikipedia.org/wiki/Sales_Pitch_(short_story)

Re: The rise of fake engine noise

#38

Post by eru » Thu, Jan 22, 2015, 4:11 AM UTC

jcromartie wrote: post #20

Noise is just wasted energy that could be doing useful work unless, of course, you actually want the noise (like in a musical instrument). This is a really weird trend.

The power in noise is actually fairly low. Like single digit watts low, for deafening noise.

Re: The rise of fake engine noise

#39

Post by h43k3r » Thu, Jan 22, 2015, 4:13 AM UTC

I don't know about other communities, but Formula 1 fans go and watch races because of sounds. The new rules in 2014 which introduced the v6 hybrid doesn't have a very loud sound and you can see the media reaction to it. Old cars used to have a v8 engine. Revs limiting is also one of the reason of low sound in 2014.

If you want an comparision between the old sound and new sound, see the below mentioned youtube video

https://www.youtube.com/watch?v=jS4Dh_EAfJI

News: http://www.theguardian.com/sport/blog/2014/mar/25/bernie-ecc...

Re: The rise of fake engine noise

#40

Post by analog31 » Thu, Jan 22, 2015, 4:15 AM UTC

baldeagle wrote: post #22

I drive a Leaf and a Volt, both technically electric cars. The sprinting power of an electric is pretty good, I often take modded civics off the line (stoplight) in the Leaf; the point being that electric cars can quickly move to a spot you don't anticipate them. The Volt has a 'pedestrian warning horn' that, when engaged by the driver, gently and rapidly beeps the horn to draw attention to the Volt. Since it is enga…

>>> As a cyclist, I enjoy having good situational awareness, and electric cars can definitely be surprising when they pass you.

The car could have a bell and "on your left" speaker. ;-)