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Normal Operating Sounds

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Re: Normal Operating Sounds

#141

Post by op00to »

bb123 wrote: post #100
spike021 wrote: post #41

Earlier quoted context omitted.

I have a relatively analogue car (Subaru BRZ) and there are times when you shut it off on a warm day and then randomly about ten mins later a radiator fan kicks on. I guess it's to help cool down but I don't remember exactly what the manual says. Basically it's cool how cars do things largely on their own sometimes to stay within certain parameters.

This is due to a phenomenon called heat soak which is where the engine temperature increases above normal for a time after it has been switched off due to the lack of coolant flow. The fan is coming on to aid cooling the engine/engine bay to reduce the effect of heat soak. With carburettor fed engines it is sometimes advised by the manufacturer to allow the engine to idle for some time after running it at high RPM. T…

I had an old Volvo that would “vapor lock” on short trips. It’s amazing how reliable cars are now compared to 20 years ago.

Re: Normal Operating Sounds

#142

Post by hennell »

sneak wrote: post #126
newaccount74 wrote: post #87

Earlier quoted context omitted.

This is the kinda good natured fun that I really liked Tesla for before they announced an armored vehicle that's designed in a way to increase the likelihood of accidentally running over your kids playing in the driveway.

Alternately, it’s designed in a way that almost all trucks and SUVs in the US are designed, in a way that is generally expected/preferred by customers who buy those vehicles. I also don’t like it, but it’s not Tesla’s fault that that’s where the market is. I’ve heard from so many foolish people who don’t understand physics that they feel safer driving a big heavy vehicle and being up high. The armor has nothing to do…

There's an interesting bit in car guys vs bean counters where the author recalls the new regulations mandating a smaller average size car. US manufacturers had to make much smaller cars to lower their average. But US customers just weren't interested. They wanted big cars, not just new cars. Japanese manufacturers (who were already lower then the regulated average) stepped in and built new big cars.

Not totally similar to your point as safety regs would be more equal, but it was an interesting revelation to me (especially as here in the EU small cars are much more desirable) that really market demands are as much of a driver of these things as manufacturer production.

Regulation has to be in the right place too, ideally giving the real trade off to the consumer. (the book suggests that if America taxed fuel more like the rest of the world so you didn't have such cheap gas, car efficiency would become a much bigger selling point, leading to more demand for smaller less ridiculous cars). But I suspect that would change less the demand for low gas cars, and more the demand for low gas tax politicians.

Re: Normal Operating Sounds

#143

Post by londons_explore »

If I was the engineering team, I would be trying to eliminate all these noises.

Every single one of these could be engineered away. For example the pops and bangs at a supercharger is the metal shield deforming when heated. Instead, it should have circular ridges stamped into it around the fixing points to let it expand against the springiness of the steel.

The clunk noise from brakes could be engineered away by using stainless steel spring clips to prevent the pads being able to wiggle around in the calipers (used by many manufacturers already).

The clunk from the contactors opening/closing could be engineered away by having the contactors open/close far slower - with a proper precharge, no current is flowing, so there is no longevity benefit of fast close/open. Or... decide not to have contactors at all - I don't really see any reason they're needed, just keep the high voltage system always energized and design all the other components to have a suitably low leakage current. For maintenance and emergency de-energization, have a manual lever or a pyro-fuse.

Re: Normal Operating Sounds

#144

Post by joshspankit »

xg15 wrote: post #136
dralley wrote: post #28

Earlier quoted context omitted.

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 re…

I find it interesting that you can find stuff like this even in biology: When you shiver in cold weather, your body is basically doing the same.

This is an aside, but as a native of winter cold: shivering is an excellent strategy to avoid death, but it’s a terrible strategy for actually feeling warm. (Better is moving, relaxing, and massaging the ears/hands/feet to promote blood flow.)

Re: Normal Operating Sounds

#146

Post by armada651 »

hennell wrote: post #142
sneak wrote: post #126

Earlier quoted context omitted.

Alternately, it’s designed in a way that almost all trucks and SUVs in the US are designed, in a way that is generally expected/preferred by customers who buy those vehicles. I also don’t like it, but it’s not Tesla’s fault that that’s where the market is. I’ve heard from so many foolish people who don’t understand physics that they feel safer driving a big heavy vehicle and being up high. The armor has nothing to do…

There's an interesting bit in car guys vs bean counters where the author recalls the new regulations mandating a smaller average size car. US manufacturers had to make much smaller cars to lower their average. But US customers just weren't interested. They wanted big cars, not just new cars. Japanese manufacturers (who were already lower then the regulated average) stepped in and built new big cars. Not totally simil…

It's an arms race though, most people prefer bigger cars because it makes them feel safer from all of the other big cars on the road.

Also it was actually the gas efficiency regulation that started the arms race, because big trucks were exempt from the regulations so car manufacturers started pushing more people towards buying trucks instead of sedans.

Re: Normal Operating Sounds

#147

Post by jon-wood »

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…

> It reminds me of how ESCs for RC vehicles use the motors to generate audible chirp tones to indicate status.

Super Mario Wonder from Nintendo recently uses the vibration motors in your controller to play sound effects in some places which I thought was an incredibly neat trick.

Re: Normal Operating Sounds

#148

Post by londons_explore »

stavros wrote: post #112
londons_explore wrote: post #102

Earlier quoted context omitted.

The efficiency of electrical resistance heating is exactly the same whether you use motor coil resistance or resistance wire. However, they simplify their system design a little (fewer contactors, fewer wires, fewer components to buy/test)

It's not the same if you generate the heat outside and bring it inside, though. I don't know enough about where the fan is located to know if that's what you mean, but that would be different.

air/air heat pumps have a fan on both the inside and the outside. In modern designs, both those fans will be brushless DC, which enables deliberate heating through software.

Note however that both fans will typically be ~150 watts - which means that when heating they can't produce orders of magnitude more heat than that. So heat produced by the fan motor, even when run to generate as much heat as possible, probably won't be a very significant contributor to overall system heat output.

Re: Normal Operating Sounds

#149

Post by londons_explore »

pests wrote: post #120
londons_explore wrote: post #103

Earlier quoted context omitted.

It's also a common cause of breakdowns... The fan normally cools the radiator, but the temperature sensor is on a coolant hose. Since the engine is stopped coolant isn't flowing so the fan isn't cooling the same thing the sensor is sensing, which means it can end up running for 30 mins or more. Since the fan can be 20 amps or so, you can easily kill old car batteries due to this effect. User comes back after an hour…

Isn't that feature the exact one being discussed in this threads in order to not overheat the engine though?

Yes, but other posters are mistaken that it is a 'clever' feature to prevent overheat during heat soak. It is instead more an accidental byproduct of the fact it is wired direct to the battery and not to the ignition circuit. Thats done to save a couple of cents on the ignition switch (no need for a large high current fan to be powered through it).

Re: Normal Operating Sounds

#150

Post by epcoa »

londons_explore wrote: post #149
pests wrote: post #120

Earlier quoted context omitted.

Isn't that feature the exact one being discussed in this threads in order to not overheat the engine though?

Yes, but other posters are mistaken that it is a 'clever' feature to prevent overheat during heat soak. It is instead more an accidental byproduct of the fact it is wired direct to the battery and not to the ignition circuit. Thats done to save a couple of cents on the ignition switch (no need for a large high current fan to be powered through it).

No you’re mistaken.

> Thats done to save a couple of cents on the ignition switch (no need for a large high current fan to be powered through it).

The fan must be powered by a relay in most cases so this is utter bullshit.

In most any modern car the fan is controlled by the ECM (a computer). Furthermore this fan relay will come on in anticipation of high heat load such as when the AC is turned on as well in cars without dual fans.

There is so much more complexity here than just wiring through the ignition circuit (which wouldn’t cost any more anyway as noted) that thinking this is a cost saving issue is utterly clueless.

And the temperature sensor that controls it is invariably located in the engine block, not the radiator hose. Modern cars may have multiple sensors but they need one in the block.

Cooling fans in most cars don’t draw 20 amps while running normally (they should be closer to 10), and while anything can fail the cooling fan in these setups should only run for a few minutes. Draining the battery like you claim is not a “common” cause of breakdowns.

You clearly don’t know much about modern (last >30 years) cars to be commenting on them so authoritatively, tone down your arrogance.

https://acurazine.com/forums/3g-tl-2004-2008-93/wiring-diagr...

This is a typical setup (and it’s 20 years ago). Debunking two of your claims. First note that the condenser fan is wired through the ignition, debunking the notion that it would be costly to do so and that running the main fan bypassed isn’t intentional. Also note that the actual fan control is the lower right black box PCM/ECM (engine computer)

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