Hyundai IONIQ Forum banner
1 - 8 of 8 Posts

·
Registered
Joined
·
91 Posts
Discussion Starter · #1 ·
ICE car efficiency (MPG) improves as the engine warmed up after you drove a few km/miles, that's what everybody said. Is that true even when the outside temp is warm like in the summer?

What about an EV? Does an EV's range (km/kwH) improve after it's been driven for a few km/miles?

I ask this because the majority of my drives are around 5km or so so my car's gas mileage is never as good as it's suppose to be. If I buy an EV like the Ioniq, does the efficiency of the car stays the same if I drive 5km or 50km given the temp, speed, traffic etc are all the same thru out the drive? Does what I ask make sense?
 

·
Super Moderator
Joined
·
2,356 Posts
On your first point it does , though it's never warm in the UK summer ;) . Even on short journeys, as you describe it will go into EV quite readily , The secret is to leave the heating off if you can .
No definite answer about the EV . I assume much the same would apply , probably one of the EV owners will chip in
 

·
Super Moderator
Joined
·
1,795 Posts
In general it is assumed that EV cars are also affected by how cold they are. But maybe less, as the number of moving parts is much smaller than for an ICE car. I also often drive short distances like 8 or 10 km. But my efficiency figures are quite OK. More impact is from the use of the heating system while driving. It is so much better to do preheating from the wall and then for a short drive leave the heater off. But I have to admit, I am sometimes a bit lazy in preheating in cases that the car does not need to be charged. Then you cannot expect the best efficiency figures.
 

·
Registered
Joined
·
3,473 Posts
Batteries of all kinds are inefficient when cold (although cold does help retain the charge). But honestly, I'd have to google it as I don't remember the details. For sure max torque won't be available until it is warm, but that is not really the efficiency you are looking for.
 

·
Registered
Joined
·
91 Posts
Discussion Starter · #5 · (Edited)
Thanks for all the reply.

I guess I am not making myself clear.

If the outside temp is 25C (75F), my gas car is still not as efficient when I start the car 'cold' (as in the car's been sitting for a while) and drive a short distance compare to if the car has been driven for 10 km and re-do the same route as when I drive the car 'cold'. Does that make sense?

I am asking does a pure EV behave the same as a gas car, in warm weather.

If I drive the EV that's been sitting for over 5 hours, drive a short distance (5 km) and measure the efficiency (km/kwH). Then continue to drive the car for 10 km, return to the original starting point, reset the km/kwH gauge and do the same 5km as when I started the car the first time. Would the km/kwH be higher this 2nd time around due to the car has been running for a while compare to when the car has been sitting for a while. As I believe my gas car will have better MPG after the car is 'warmed up' compare to when the engine is 'cold' doing the same route. Assuming all other conditions are the same (temp, wind, speed etc).

Does my question make more sense now or am I still confusing everyone?
 

·
Registered
Joined
·
342 Posts
PPl have awnsered you, but i'll give it a go to... :p


- Fossil cars need to warm up the engine and oil up the moving parts up to operating temperature before it get most efficient. (0,42l/10km vs 0,65l/10km)
- EV's does not have to do this, meaning yes, you will get close to the same effisiency "cold" as "warm"... (1,2kWh vs 1,2kWh)

<--- The above statements are with NO AirCondiotion / Cabin heating! (as everyone are saying)


If you include warming the cabin, stearing weel, rear window and seatwarmer.
Then ofc the consumtion in kWh will be higher for short trips.

And if you start driving again after it has been warmed up, it will use a bit less, as it doesnt have to heat the cabin as mutch.
The consumtion is so low, and the range compared to short trips, its not a problem if the consumption turns out to be 2,5kWh/10km...?

While max heating with heatpump the car shows it uses 6kW+ to heat the cabin, for a short couple of minuts.
 

·
Registered
Joined
·
3,473 Posts
The very simple answer is no. Your electric car will suffer no efficiency loss in warm weather when starting "cold".
 

·
Registered
Joined
·
260 Posts
Thanks for all the reply.

I guess I am not making myself clear.

If the outside temp is 25C (75F), my gas car is still not as efficient when I start the car 'cold' (as in the car's been sitting for a while) and drive a short distance compare to if the car has been driven for 10 km and re-do the same route as when I drive the car 'cold'. Does that make sense?

I am asking does a pure EV behave the same as a gas car, in warm weather.

If I drive the EV that's been sitting for over 5 hours, drive a short distance (5 km) and measure the efficiency (km/kwH). Then continue to drive the car for 10 km, return to the original starting point, reset the km/kwH gauge and do the same 5km as when I started the car the first time. Would the km/kwH be higher this 2nd time around due to the car has been running for a while compare to when the car has been sitting for a while. As I believe my gas car will have better MPG after the car is 'warmed up' compare to when the engine is 'cold' doing the same route. Assuming all other conditions are the same (temp, wind, speed etc).

Does my question make more sense now or am I still confusing everyone?
An internal combustion engine needs to warm up to be efficient mainly because gasoline vapors will condense on the cold cylinder walls and other parts that the fuel/air mixture touches. Gasoline doesn't burn; only gasoline vapors burn, and some of the fuel/air mix will condense on cool surfaces until they heat up. The fuel injection system compensates for this condensation by enrichening the fuel/air ratio till the engine warms. Oil viscosity is also very high at room temp compared to operating temps, but that's a secondary effect.

An electric motor and all the electronic parts will be more efficient when cool. The battery will be most efficient at about room temp. It will warm with use as will all the other electronic parts. The time to do a drag race with an electric motor is when everything is cold and the battery is room temp. So to answer the 2nd part of your question, the BEV will be less efficient after getting warm. Heat makes everything have more resistance and resistance is the enemy of efficiency.
 
1 - 8 of 8 Posts
Top