Submitted by Auguste-67 t3_ygo4xm in explainlikeimfive
I hear a lot about aerodynamics for EVs and how it’s important to increase the range, but isn’t it as important on "normal" cars ? Like it’s definitely beneficial but how is it more beneficial for EVs ?
It is but normal cars need radiator openings for cooling and their wheel rims are also designed to somewhat aid in brake cooling which also isn't very aerodynamic. I read if you remove the Tesla wheel covers you will lose range.
While the radiator is true. Evs also have brakes. They just have 2 sets. Motors and brakes.
They don't need the increased cooling at the cost of aero efficiency.
You don't need increased cooling in brakes unless you're racing and using them constantly at high speeds.
Or going down a steep decent…
if regenerative braking does half the job, only half of the heat is generated by the mechanical brakes, and half the cooling is required.
Until the regenerative capacity is full and have to rely entirely on friction brakes. You don’t engineer for optimal operating conditions.
> Evs also have brakes. They just have 2 sets. Motors and brakes.
while this is true, because of regenerative braking, the hydralic/mechanical brakes aren't at as much risk for overheating and therefore do not have the same cooling requirements.
as with everything else, optimization of cooling versus aerodynamics is required. and with electric vehicles and regenerative braking, aerodynamics can be prioritized more than with your typical ICE sportscar, where braking performance and cooling is prioritized.
That's also true for icb-cars, you can use the motor and transmission to brake, at least with manuals, I don't know about automatic. Still, regen braking has greater stopping power.
Yes you can break with your engine. But I'm fairly certain you want to avoid that as you don't want to wear out your trans any faster than normal. Motors work in reverse when breaking and don't wear out as fast as breaking with your engine.
Where the power comes from doesn’t matter. Look at jets for instance. They’re fuel burners and the slipperiest things we have made.
It’s done to increase mileage and efficiency of the energy used.
The problem I think is still because there is no proper solution to charge an EV as fast as you can pump gas in a normal car. If charging EVs was as quick they wouldn't think about it.
This is the answer. It'd be faster to take the whole battery out and leave it charging and put another one in fully charged (I've seen videos of someone doing that with electric motorcycles in Taiwan iirc).
Now, hydrogen cell cars are electric and they are charged very fast, but they are not competitive in small cars and it's impossible to find a charging station in the middle of nowhere since H2 can't be pumped all the way there. They will replace buses, trucks and large ships soon, tho, because as batteries price go up, making hydrogen from water remains cheap.
The effect is identical, but the economics of EVs are such that they barely make sense at the moment, such that it's much more important for them to stretch every single potential advantage in range they can get. One of those is reducing aerodynamic drag.
You've got a fair few answers here, but none really go into why aero is important, or the actual differences between gas / Diesel engines and EVs. I'm coming from this from the viewpoint of someone who works with this stuff, though not an aero engineer.
The first thing here is that gas (petrol and diesel) and EVs are tested for range and efficiency in the same way, so aero has the same relative effect. The way that they're tested depends where in the world you are. In the US, it's the EPA drive cycle (exactly which drive cycle depends on the type of vehicle), most of the rest of the world uses WLTP, and China uses CLTC (which is basically WLTP). The point here is that the drive cycle (a specific set of accelerations and speeds, conducted over a set period of time) is exactly the same in any territory for the same type of vehicle. That means that it makes no difference if it's an EV or petrol engine. Therefore the effect of aero is the same for everything.
So from that, EVs don't benefit any more from aero than any other vehicle.
But....there't more to it. EVs, despite a massive increase in popularity over the last few years, still have a public perception problem with lack of range. Every mile (or km) you can get out of an EPA drive cycle test, gives you a better figure that you're allowed to advertise. But then....range isn't everything. Efficiency is what actually matters from a design point of view. For every Watt of power you can save, you need a smaller battery to give you the same range. Or you can have better efficiency and the same size battery to give you better range. It's a design balancing act of cost to the consumer vs what is actually desirable in market.
The other point worth raising is that the "aero" isn't just aero. Although it's common to pick up on a drag factor, like "oooooh this car has a 0.87 [cd] drag factor, isn't that great?", by itself it does't mean anything. You also have to look at the the aero uplift and the reacting areas to actually understand how aero is playing a part in efficiency,
Thank you it makes a lot of sense
If cost of power (is fuel vs grid electricity) is the main factor, then aerodynamics are more important on a gas/diesel vehicle--especially at highway speeds where power consumption shifts towards air resistance induced by higher speeds vs the greater weight of EVs. If range is the major consideration, then electric.
Presumably, as EVs typically have a "skateboard" design with a layer of batteries near the base, it would be easier to design the front of a BEV for greater aerodynamics.
EVs are less efficient at high speeds, so there's more to be gained by improving aerodynamics. ICEs would gain more by improving stop-and-go efficiency.
robot_egg t1_iu9jmju wrote
The effect is identical between EV and ICE cars. It's just that a typical EV or hybrid driver is more interested in getting high energy efficiency compared to a typical ICE driver, and the manufacturer put money and resources on what will drive sales of each model.