Re: [图表]英国实测19款电动车可行驶里程 前3没T

楼主: hanchueh (RaidenHC)   2019-08-21 10:17:30
知名电动车网络媒体 InsideEVs 有篇报导回应这个结果。
原文网址:
https://insideevs.com/news/365941/what-car-different-results-epa/
原文:
We searched for explanations. And here are the answers.
When we wrote to you about the real-life EV range ranking made by the British
magazine What Car?, we got curious by huge differences in what the magazine pr
esented and what EPA discloses with its ratings.
Four vehicles made us wonder: the Tesla Model S75D and the Model X100D, whic
h lag behind by around 50 miles of range, and the Jaguar I-Pace and the Kia Ni
ro EV, which get around 20 miles more than in EPA ratings. Why? One explanatio
n is that the differences relate to WLTP and EPA cycles, but we found out ther
e’s way more to it than it seems. Most of all, it has to do with electric car
s being entirely different animals from ICE cars.
We contacted Steve Huntingford, editor of咗hat Car?, to ask him what caused su
ch differences. Hard feelings due to the Independence? A protective approach t
owards Jaguar and the Korean brands? Joking aside, it has to do with each manu
facturer’s priorities for him.
“The nature of the (European) WLTP cycle is different from the (US) EPA cycle
. The EPA test emphasizes long-distance cruising, which of course is more comm
on in the US, with its geographic nature. WLTP is about shorter, start-stop dr
iving, more common in Europe,” said the editor.
Huntingford believes that the Kona (Kauai, in Portugal) and the Niro EV are re
latively small cars, more European focused. So they would have been tuned to g
o well in WLTP tests. Tesla models, on the other hand, would be more focused o
n the US, and thus tuned to perform better in EPA cycles. The I-Pace adopts a
more neutral approach towards the two test cycles.
We have then spoken to some engineers and to Tesla about this explanation. For
the engineers, although they think it is feasible that different cycles have
an impact, the real problem is testing electric cars as if they were combustio
n-engined vehicles.
While ICE cars are also affected by aerodynamics, weather conditions and mass,
electric cars are way more sensitive to that. They are made to be as efficien
t as possible due to the fact that their battery packs, although with more ran
ge than ever in history, are still limited. And take longer to get back to bus
iness.
One good example of that was Jason Fenske’s road trip with his Model 3. He tr
aveled 1,963 miles on 560 kWh. Or on the equivalent to the energy contained in
a 16.6 gallons gas tank. That’s a little less than the 18 gallons a 2019 Chr
ysler 300 fuel tank can hold. Can you imagine this sedan running 2,000 miles o
n a single gas tank? Neither do we.
With that sort of efficiency, anything can make the car present a longer or sh
orter range. More wind or less. Temperature. Traffic. The way the guy behind t
he wheel drives. Electric cars try to compensate for that with regenerative br
aking and other strategies.
Most of the engineers we interviewed preferred not to speak on the record. The
y claim to have no idea how What Car? conducts its testing despite the compreh
ensive description the magazine offers. Fair enough, but they were unanimous i
n stating electric cars should be tested until their batteries are completely
depleted.
And why is that so? Because this would be the only way to check what the energ
y recovery systems in an electric car can do. Tesla cars have battery packs fo
r longer ranges, which implies their regenerative brakes only start to make a
difference when the charge is not at its full capacity anymore.?
Cato Standal, who had his Tesla Model S battery pack replaced in Norway, remem
bers this behavior as the strongest indication his new batteries were restrict
ed by software. "What makes me be 100 percent certain that this is a software
limitation is that now I have full regeneration even if the battery is fully c
harged. If the battery was 100 percent charged, you would not get more power,"
he told Tek.no.
Some of the engineers we spoke to go even further and say tests with electric
cars could never be performed on a track. For them, they should be done in lab
s with dynamometers, under very controlled conditions. That would be the only
fair scenario to compare different vehicles.
This is precisely what EPA does. And the fact that its results are different f
rom the ones presented by What Car? could be an indication that, no matter how
professional our colleagues are in dealing with the tests, they just should n
ot be performed as they are with ICE vehicles.
There’s more to it. The idea that different cycles would present very differe
nt results due to longer or shorter distances seemed strange to Ricardo Takahi
ra, a member of the SAE Brazil Technical Board for Electric Vehicles.
“Electric vehicles do much better at short distances than on the road. An EV
that is calibrated to perform well in long distances theoretically will do eve
n better in short ones. It needs less energy to move at low speeds with little
air resistance”, said Takahira.
We have also spoken to EPA and the agency also recommends all tests are made i
n labs with dynos. Not surprisingly the way it performs its tests. Over-zealou
sness? Perhaps when it relates to combustion-engined cars, but not with EVs du
e to the energy regeneration's influence.
Tesla also responded to our inquiries and said the following:
“These results are wrong and not reflective of the WLTP results determined by
European regulators due to the fact that What Car? conducted an abridged test
without fully depleting the vehicle’s battery. Using only a fraction of a ca
r’s total range and attempting to extrapolate that result as a proxy for its
full useable range is simply incorrect.
We also believe the vehicles included in the tests were not tested under the s
ame exact conditions, which means the test results cannot be directly compared
. True comparative results can only be achieved under lab conditions, which is
why standard test procedures like WLTP are used to measure and compare vehicl
e range.”
Magazine tests probably could never be conducted in labs, due to costs. Newsro
oms increasingly count on fewer people doing more things, which makes a long t
est very difficult for a journalist to perform. Anyway, when it comes to elect
ric vehicles, it seems there is no other choice.
Although this has happened with What Car?, it could happen to any other specia
lized magazine. It probably is happening with many around the world that are n
ot aware of the unique characteristics of electric cars.
What Car? will probably want to prove their methods are solid by doing at leas
t some of them as recommended by Tesla and the engineers we spoke to. Or else,
until a full charge ends completely. With independent parties to certify ever
ything was done by the book. And it may eventually prove its point, despite do
ubts from the people we interviewed.
While What Car? does not do that, we recommend our readers to pay attention to
test methods regarding energy consumption. If they are not performed until th
ere is no single Wh left on the battery pack, stick with official rankings, su
ch as EPA's. This probably is the safest way to check the efficiency of an ele
ctric car when compared to others.
重点翻译:
原文指出 Tesla Model S/X 的 EPA 结果比杂志测试的多了50英里,而Jaguar I-Pace却
是反而杂志比 EPA 多20英里。
一个可能性是杂志的测试比较接近欧洲人开车习惯,把重点更多放在短程的城市驾驶,而
美国的 EPA 为了模拟美国使用状况,更着重长途的远程续航力。
还有就是因为电量的限制,电动车都是设计成极度省能源的车,Model 3实测开1963英里
花了560度,那个电量换算成汽油的能量密度相当于16.6加仑(62.8L),有哪台油车满缸可
以开两千英里的呢?在效率这么高的状况下,任何一点变量都有可能对电耗造成很大的影
响,比如风速、温度、车流量、驾驶习惯。因此电动车靠煞车动力回收来抵抗这些外来因
素。
所以,多数工程师都建议实际续航力应该真的测到电池用完,而不是只有31.2公里,这样
才能真正考验电动车的动力回收能力。
另外有一些工程师认为要真正比较不同电动车的能力,一定要在封闭测试环境才公平。
特斯拉官方回应:“这个测试结果是错误的,而且也不符合 WLTP 的测试结果,因为 Wha
t Car? 杂志测的距离太短,并没有实际上把电池电量用完,只拿很短的距离来估电动车
实际的续航力是不对的。
我们相信这个测试也没有很严格的保证不同车子测试的条件环境是相等的,所以结果无法
比较。要公平的比较不同车辆必须在实验室比,这也是为什么要有 WLTP 这种标准测试。

个人心得:
我觉得这个测试最严重的问题就是要比续航力竟然不直接从100%开到0%,而是只开31.2或
是62.4公里就停。很有可能这短程内根本不需要什么煞车,所以没办法比较各家的动力回
收能力。要比续航力还是把电池开到没电吧!
只开短程公里,当然是那些欧洲才买得到的小车会比较吃香,电耗较低,但那些车子根本
跑不远。BBC的知名英国车媒Top Gear实测I-Pace也不到322公里。
英国的研究还是看看就好。
作者: XXXXBANG (XXXXBANG)   2019-08-21 10:33:00
你再去看一次原文吧 What Car测试的距离明显不只31.2公里 测试时也有煞车跟加速
作者: Scape (non)   2019-08-21 11:28:00
推翻译
作者: king12272 (Matt)   2019-08-21 11:37:00
作者: ru04hj4 (纯朴乡下人II)   2019-08-21 11:39:00
这种测试就给通勤做参考 短程特斯拉就没优势
楼主: hanchueh (RaidenHC)   2019-08-21 11:40:00
短程特斯拉还是优于所有油车 只输给那些小电车但那些小电车本来就开不远 顶多200多公里
作者: NKAC   2019-08-21 11:43:00
推翻译
楼主: hanchueh (RaidenHC)   2019-08-21 11:44:00
不过60kWh的韩/日电车就很有竞争力 可以跑三四百公里电耗也能赢特斯拉 这时候特斯拉大概只剩性能 空间 安全还有辅助驾驶能力还能赢
作者: chandler0227 (钱德勒)   2019-08-21 14:24:00
跟短长程较无关,主要是车辆耗电跟充电量转换效率
楼主: hanchueh (RaidenHC)   2019-08-21 17:26:00
误差高的测试 你只测一次当然不够

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