3 ms·

> A cars cooling system is designed around that and the case where you need all 150 horsepower for 5 seconds, then drive for 30 seconds at 20 horse power befor

> A cars cooling system is designed around that and the case where you need all 150 horsepower for 5 seconds, then drive for 30 seconds at 20 horse power before slamming on the brakes My old 2004 Opel 1.6, 105hp could deliver almost full load (car fully packed with passengers and baggage, with roof trunk also packed, going 140km/h uphill with fully open throttle, fuel usage was reported as 16L/100km, typical road usage was 8L/100km) for about half an hour without any problems.

ilyt 3y ago
with 140km/h wind to cool it in addition to radiator fan
- yetihehe 3y ago
  I don't think fan was engaged anyway, never noticed it working when moving, only when stationary. I don't think it would help anyway. What I mean - cars can do fine for long periods under load as long as they are cooled appropriately, not only for 10s of full power.
  - wkat4242 3y ago
    You look under the hood to see your fan moving while you're doing 140km/h? ;)
    - yetihehe 3y ago
      No, but I can hear it easily when car is idle, also see a change of power used by engine (fuel usage goes from 0.8L/h to 1.2L/h, not a small change). I purposefully wrote that I THINK that it doesn't work at speeds, because indeed it can be hard to notice it when going highway speeds. I would have to verify it probably with some CAN reader, but I think at speeds >40km/h it's not worth it to start the fan, air should be enough.
      - ilyt 3y ago
        It wouldn't on highway, only time where extra cooling would be needed if you were on actual track where you'd have far higher average power on top of slower average speed.
NoImmatureAdHom 3y ago
>Your *American car engine can typically...
- thsksbd 3y ago
  Agreed, only in America; and thank goodness for that. I literally stopped at the Ford dealer today; there, I told the sales lady trying to sell me on the F150 that, for a few more thousand dollars, I prefer the F250 because I don't want a dinky euroboost 2.7 L turbo V6. Luckily the F250 has a 6.8L V8 base.
  - AtlasBarfed 3y ago
    For what? Basically sounds like your typical American that buys a massive car truck. Just a drive around suburbia with for no real practical reason and F-250 would be ridiculous for that. I'm glad every American male feels compelled by Ford and GM's advertising to buy 70 and $80,000 trucks because we'll be that much easier for them to budget out for EVs when they start coming out
    - thsksbd 3y ago
      Honestly? On the remotely unlikely event that I have an opportunity to switch on the high idle switch if some extinction folks block the road on the way back from soccer practice two miles away.
- mardifoufs 3y ago
  Opel basically does not exist in the US.
  - RecycledEle 3y ago
    Opel was General Motor's European brand until 2017. They sold very different cars in Europe than they did in the USA, but it was the same company.
Retric 3y ago
In the end it’s all about the load not the horsepower. Doing the job of a 100hp engine with a 300hp engine doesn’t require 3x the cooling. So companies happily sell higher trim levels with more HP while keeping the same radiator. Smaller engines are designed to operate at higher percentage of maximum capacity at lower speeds. Roll back to the days of 40hp engines and they max out highway speeds and can sustain that for hours. As you keep adding HP the maximum sustained load at a given speed doesn’t increase. So, 1000+ HP super cars can make use of that power at 200+ mph, but they don’t waste weight having radiators large enough to dissipate that heat continuously at 85mph because there’s no way the car is staying that slow while applying that much power. External temperature also plays a role, cars need to be able to handle highway speeds at 45C adding headroom at lower temperatures. Trucks also need to be able to do that while towing a large load.
numpad0 3y ago
25hp = 19kW or ~1x standard 42U rack, 105hp = 78kW or 20x typical households. Cars are powerful machines!
- Retric 3y ago
  That’s the useful work which represents ~1/3 of the energy in gasoline. ICE cars needs to deal with ~2x that energy in waste heat.
  - Baeocystin 3y ago
    A good rule of thumb is 1/3 of the energy into mechanical work, 1/3 into the cooling system, and 1/3 out the tailpipe. The actual numbers are pretty close to this across a wide range of operating conditions.
    - Retric 3y ago
      With the caveat that in cars the very long exhaust system dissipates a great of the heat rather than all of that energy literally coming out of the tailpipe as hot gas. Also catalytic converters provide more complete combustion and thus generate even more heat.
  - AtlasBarfed 3y ago
    Well, heat your water with it. In addition, I don't see why you wouldn't just buy a home battery pack and use that to store up energy. You can run the ice in the high power bursts to top off. I just kind of like this post because there's going to be a lot of excess ICE engines out there once EVs take over the primary job of consumer transport. Would be nice to have a DIY recipe to convert them over to leveling for your solar grid at home
    - numpad0 3y ago
      IIUC the significant fractions of heat can't be absorbed, else it eats into efficiency, which is okay if part of the purpose of the engine is for heat - I think he's just pointing out the hydrocarbon-to-kinetic conversion ratio is around 1/3rd, which is a useful rule of thumb.

ilyt 3y ago

with 140km/h wind to cool it in addition to radiator fan

yetihehe 3y ago
I don't think fan was engaged anyway, never noticed it working when moving, only when stationary. I don't think it would help anyway. What I mean - cars can do fine for long periods under load as long as they are cooled appropriately, not only for 10s of full power.
- wkat4242 3y ago
  You look under the hood to see your fan moving while you're doing 140km/h? ;)
  - yetihehe 3y ago
    No, but I can hear it easily when car is idle, also see a change of power used by engine (fuel usage goes from 0.8L/h to 1.2L/h, not a small change). I purposefully wrote that I THINK that it doesn't work at speeds, because indeed it can be hard to notice it when going highway speeds. I would have to verify it probably with some CAN reader, but I think at speeds >40km/h it's not worth it to start the fan, air should be enough.
    - ilyt 3y ago
      It wouldn't on highway, only time where extra cooling would be needed if you were on actual track where you'd have far higher average power on top of slower average speed.

NoImmatureAdHom 3y ago

>Your *American car engine can typically...

thsksbd 3y ago
Agreed, only in America; and thank goodness for that. I literally stopped at the Ford dealer today; there, I told the sales lady trying to sell me on the F150 that, for a few more thousand dollars, I prefer the F250 because I don't want a dinky euroboost 2.7 L turbo V6. Luckily the F250 has a 6.8L V8 base.
- AtlasBarfed 3y ago
  For what? Basically sounds like your typical American that buys a massive car truck. Just a drive around suburbia with for no real practical reason and F-250 would be ridiculous for that. I'm glad every American male feels compelled by Ford and GM's advertising to buy 70 and $80,000 trucks because we'll be that much easier for them to budget out for EVs when they start coming out
  - thsksbd 3y ago
    Honestly? On the remotely unlikely event that I have an opportunity to switch on the high idle switch if some extinction folks block the road on the way back from soccer practice two miles away.
mardifoufs 3y ago
Opel basically does not exist in the US.
- RecycledEle 3y ago
  Opel was General Motor's European brand until 2017. They sold very different cars in Europe than they did in the USA, but it was the same company.

Retric 3y ago

In the end it’s all about the load not the horsepower. Doing the job of a 100hp engine with a 300hp engine doesn’t require 3x the cooling. So companies happily sell higher trim levels with more HP while keeping the same radiator. Smaller engines are designed to operate at higher percentage of maximum capacity at lower speeds. Roll back to the days of 40hp engines and they max out highway speeds and can sustain that for hours. As you keep adding HP the maximum sustained load at a given speed doesn’t increase. So, 1000+ HP super cars can make use of that power at 200+ mph, but they don’t waste weight having radiators large enough to dissipate that heat continuously at 85mph because there’s no way the car is staying that slow while applying that much power. External temperature also plays a role, cars need to be able to handle highway speeds at 45C adding headroom at lower temperatures. Trucks also need to be able to do that while towing a large load.

numpad0 3y ago

25hp = 19kW or ~1x standard 42U rack, 105hp = 78kW or 20x typical households. Cars are powerful machines!

Retric 3y ago
That’s the useful work which represents ~1/3 of the energy in gasoline. ICE cars needs to deal with ~2x that energy in waste heat.
- Baeocystin 3y ago
  A good rule of thumb is 1/3 of the energy into mechanical work, 1/3 into the cooling system, and 1/3 out the tailpipe. The actual numbers are pretty close to this across a wide range of operating conditions.
  - Retric 3y ago
    With the caveat that in cars the very long exhaust system dissipates a great of the heat rather than all of that energy literally coming out of the tailpipe as hot gas. Also catalytic converters provide more complete combustion and thus generate even more heat.
- AtlasBarfed 3y ago
  Well, heat your water with it. In addition, I don't see why you wouldn't just buy a home battery pack and use that to store up energy. You can run the ice in the high power bursts to top off. I just kind of like this post because there's going to be a lot of excess ICE engines out there once EVs take over the primary job of consumer transport. Would be nice to have a DIY recipe to convert them over to leveling for your solar grid at home
  - numpad0 3y ago
    IIUC the significant fractions of heat can't be absorbed, else it eats into efficiency, which is okay if part of the purpose of the engine is for heat - I think he's just pointing out the hydrocarbon-to-kinetic conversion ratio is around 1/3rd, which is a useful rule of thumb.