One other factor Mercedes did to make the automobile extra environment friendly was to restrict the frontal space. The EQX has a frontal space of two.12 sq. meters. This places its frontal space beneath that of the Toyota Prius or Tesla Mannequin 3, that are round 2.2 sq. meters.
Weight Discount & Cooling
Based on Mercedes, the focused speeds for this automobile imply that weight is about 20% of the automobile’s vitality use. This implies it issues, however not as a lot because the aerodynamics do (one thing we’ve seen in different folks’s testing with trailers). Mercedes did need to see if it may scale back these numbers, as a result of they’d already eked out the entire effectivity they may from aero with out going into plane territory just like the Aptera.
The corporate managed to get the burden right down to 1755 kg (3869 lb). That is no light-weight automotive, however it’s nonetheless quite a bit lighter than the EQS. A method they ditched weight was to make use of experimental battery cells with greater vitality density, and to make use of a passive cooling system, which reduces the battery pack weight additional. There are some severe drawbacks to that call (the Nissan LEAF is a superb instance), however they did use some restricted liquid cooling across the outdoors of the pack.
Mercedes bought round needing as a lot cooling by having an environment friendly drivetrain that labored the batteries much less, however one drawback is that quick charging nonetheless heats up packs. So, to “remedy” this drawback, they decreased the charging fee to 120 kW. However, with the automobile’s effectivity, you continue to get respectable miles added per minute at that cost fee. It really beneficial properties extra vary per minute than a 350 kW Hummer EV.
The longevity subject is much less as a result of the automobile makes use of much less vitality per mile. This theoretically means fewer cost cycles per yr, that means it may nonetheless have the longevity of an EV with higher battery cooling.
Tires (Rolling Resistance)
One other necessary factor Mercedes did to get higher effectivity was to make use of low rolling resistance tires. You may study much more about tires and the way they obtain low rolling resistance with EVs by watching one other Engineering Defined video I recapped and mentioned right here.
Mercedes wouldn’t inform a lot concerning the tires (commerce secrets and techniques), however they do function close to 50 PSI and have a really low coefficient of rolling resistance. As soon as once more, the corporate is pushing the bounds of what it may well do whereas nonetheless making a automotive that individuals will suppose appears like a automotive.
Different Components
Mercedes says that the aero makes up 62% of vitality use at freeway speeds, weight/rolling resistance makes up one other 20%, and that leaves one other 18% of vitality use that may be attributed to numerous different issues.
These different issues embody powertrain effectivity, energy electronics vitality utilization, local weather management, and regenerative braking. However, for freeway vary, regenerative braking isn’t actually an enormous deal like it might be within the metropolis (assuming you aren’t hypermiling a lot that individuals hate you). For drivetrain effectivity, Mercedes selected a very tall gear ratio (the second pace from an upcoming two-speed transmission) to assist maintain vitality utilization down. This implies much less torque multiplication for acceleration at low speeds, however this was a sacrifice it was keen to make for freeway effectivity to make the objective.
Probably the most spectacular factor Mercedes was in a position to accomplish with all of this was a 95% environment friendly powertrain. This implies there isn’t a lot in the way in which of frictional or different vitality losses as the facility goes from the battery to the wheels. This in all probability required some actually good lubricants and plenty of different selections made proper (and never low cost).
Mission Completed
With all of those design selections and engineering efforts, the Mercedes group was in a position to obtain their objective of driving 1000 km (round 600 miles) on 10o kWh of battery, and on two separate routes in Europe. The general effectivity figures have been 8.3 kWh/100 km, or 7.5 miles/kWh.
How We Can Break The Limits
There’s one factor that’s painfully apparent from all of this: that conventional automotive expectations have been holding Mercedes-Benz again. May it have achieved a decrease drag coefficient? Sure, however they’d must do issues folks wouldn’t like. May Mercedes have decreased frontal space? Positive, however at the price of inside area, seating, and different issues folks count on from a automotive. Different issues, like weight, tire rolling resistance, and HVAC all put limits on what the designers may do with out changing into too unusual for the common automotive purchaser to contemplate.
Aptera’s Gamma Improvement Automobile. Picture supplied by Aptera.
What’s actually unhappy is that we’ve recognized for 100 years learn how to make extraordinarily environment friendly automobiles. The data {that a} teardrop/airfoil form, and derivatives just like the “half-body” teardrop have been recognized to be probably the most environment friendly potential form since no less than 1922. However, the automotive trade has been struggling to compromise and get as shut as they may since then.
Whereas most individuals would describe vehicles just like the Aptera or the ElectraMeccanica Solo as “clown vehicles” or “bizarre” (after they’re not being extra gross and referring to human gametes), folks keen to suppose just a little extra about it fear extra about what folks would consider them in the event that they have been driving one (and we return to the insults). Tradition punishes folks for stepping too far out of the norm, even on one thing that shouldn’t matter, like a automotive.
Even when appears don’t matter in any respect, and an organization ought to be pondering when it comes to {dollars} and cents, and its workers don’t get any say in how the automobile appears, we nonetheless see many patrons suppose conventionally as a substitute of in search of methods to save cash and enhance income. However, solely a slim majority of vehicles use issues like facet skirts and/or trailer tails in the USA, regardless of the financial losses firms refusing to undertake the know-how endure.
So, breaking the limitations that maintain automobiles from changing into extra environment friendly isn’t a technological query. It’s well-known learn how to make automobiles extra environment friendly. The issue is that tradition must be extra versatile and encourage vitality effectivity as a substitute of reinforcing traditionalism in automotive design.
One Massive Factor To Keep in mind About What Impacts EV Effectivity
One other factor that I’ve talked about earlier than, however was illustrated higher right here, is what elements have an effect on the effectivity of an EV, and the way a lot they every matter. It varies with pace, however at freeway speeds, aerodynamics are round 62% of the vitality use, which makes it a a lot larger issue than most suppose. With weight and rolling resistance solely making up round 20% of the vitality utilization, which means aerodynamic effectivity is about thrice extra necessary and thrice extra highly effective.
Because of this in case you actually need to enhance effectivity, aerodynamics is the primary place you look, and never the final. It additionally signifies that in case you should select between enhancing aerodynamics and decreasing weight, that it is best to select to do one thing concerning the aerodynamics as a result of it’s going to make a a lot larger distinction.
One sensible software of this data for EV drivers comes while you run out of cargo area contained in the automotive. Roof racks are a well-liked possibility, and one which many individuals select for aesthetic causes even after they’re not carrying something. However, placing the cargo on a hitch rack or hitch field would imply that you may carry much more weight with much less gasoline consumption.
Plus, in case you transcend typical European freeway speeds (such as you’d do on the pace restrict in a lot of the USA), the system ideas much more in favor of aerodynamics being extra necessary than different elements. If all you took away from the video was the significance of aero, you then’ve come away with one thing helpful!
Featured picture: The Mercedes-Benz Imaginative and prescient EQXX, picture supplied by Mercedes-Benz.
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