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Just_a_fan wrote: ↑

28 Apr 2020, 13:39

Andres125sx wrote: ↑

28 Apr 2020, 11:38

I'm aware about drag, but drag difference is not that high between modern and old cars and engine braking difference is very noticeable even at 50kmh when drag is negligible

Modern cars will have only 60% of the drag of old cars. That's a big difference.

Then I guess you´re thinking about 70´s cars, while I was thinking about 2000 cars, or at least that was my comparison when I said modern cars have no engine braking compared to old ones

Edit: I have even test hitting the clutch to stop any engine braking, over 80-90km/h drag is more noticeable than engine braking, also due to the longer gear I guess, but under 60-70km/h drag is negligible. Even mechanical drag is higher (deceleration is quite constant up to still). But engine braking is very high at low speed. You can test it yourself as I´ve done, try flooring the clutch while on flat terrain to see how strong is drag deceleration, then release the clutch again and you´ll learn how much engine braking your car really has. Not sure about other cars but I´ve compared a 2010 bmw with a 2000 megane and difference was massive, simply impossible to not notice it

Ferry wrote: ↑

27 Apr 2020, 18:18

J.A.W. wrote: ↑

27 Apr 2020, 10:08

How many passenger cars do you see towing anything these days?

A whole lot! I guess that is very different in different markets. Tow hitch on small cars like VW Golf or similar is very common here. Not many pick-up trucks though. One of the big selling points for Tesla 3 here is the possibility to tow. And EVs have more than 50% market share here now. https://cleantechnica.com/2020/02/05/no ... r-on-year/

Impressive numbers, didn´t know EV sales are that high anywhere

Just_a_fan wrote: ↑

28 Apr 2020, 13:39

Modern cars will have only 60% of the drag of old cars. That's a big difference.

well ...
aerodynamic drag is only part of the total drag ie there's also mechanical drag aka 'rolling resistance'

mechanical drag is ever-present ie broadly independent of speed but of course dependent on vehicle weight
but of course aero drag is very airspeed-dependent

so at low speeds aero drag is negligible and mechanical drag is dominant
hence the (relatively) poor BEV overall efficiency shown at low speeds
due to high vehicle weight and (relatively) poor electrical package efficiency at low rpm/partial powers

henry wrote: ↑

27 Apr 2020, 11:12

...

I also expect the CV lockdown to result in a lot of data on the effect of reduced traffic on pollution levels in urban environments. If the levels go down to a level that is felt to be significant one outcome may be more cities reducing the use of ICEs in their environment. An issue for hybrids will then become one of proving they aren’t using the ICE when used in those locations.

Here’s a paper that would contribute weight to that scenario. Another study of pollution vs CV deaths. This time 4 European countries analysed.





https://www.sciencedirect.com/science/ ... 15#coi0005

The pollution may not be a direct contributor but rather is implicated in the pre-existing conditions that are associated with CV.

It seems to me that the lockdown approach to controlling CV is resulting in a lot of data about the effect of pollution levels on health and climate change. In the context of this thread analysis of this data is likely to shed light on the place of BEVs in our future lives.

essentially the public-air NOx comes from diesel engines worked hard in and near cities - ie from trucks not from cars
(and there's private-air NOx from cookers etc)

as shown in our publicly-subsidised Channel 4 TV - commissioned independent tests around 'Dieselgate'
(these publicised as showing diesel cars to be NOx city-polluting but actually showed the opposite)

so increased takeup of electric cars won't change this

Tommy Cookers wrote: ↑

29 Apr 2020, 18:40

essentially the public-air NOx comes from diesel engines worked hard in and near cities - ie from trucks not from cars
(and there's private-air NOx from cookers etc)

as shown in our publicly-subsidised Channel 4 TV - commissioned independent tests around 'Dieselgate'
(these publicised as showing diesel cars to be NOx city-polluting but actually showed the opposite)

so increased takeup of electric cars won't change this

What relation are you doing between diesels and EVs? Explain please, because I see your post as complete nosense

Andres125sx wrote: ↑

30 Apr 2020, 08:04

Tommy Cookers wrote: ↑

29 Apr 2020, 18:40

essentially the public-air NOx comes from diesel engines worked hard in and near cities - ie from trucks not from cars
(and there's private-air NOx from cookers etc)

as shown in our publicly-subsidised Channel 4 TV - commissioned independent tests around 'Dieselgate'
(these publicised as showing diesel cars to be NOx city-polluting but actually showed the opposite)

so increased takeup of electric cars won't change this

What relation are you doing between diesels and EVs? Explain please, because I see your post as complete nosense

He's saying that as diesel cars didn't appear to be a major source of urban NOx levels, the switch to EV cars won't have much effect on urban NOx levels.

At least that's what I think he's saying.

I think what he says is what some brands advertise with. "this diesel cleans the air"

So suppose you have very dirty air because of a lot of pollution, but the car emits less NOx or finedust whatever than is in the air.. Than the car 'cleans' the air.

So only the vehicles which are more pollutant than the air already is are pollutant

Just_a_fan wrote: ↑

30 Apr 2020, 12:28

Andres125sx wrote: ↑

30 Apr 2020, 08:04

Tommy Cookers wrote: ↑

29 Apr 2020, 18:40

essentially the public-air NOx comes from diesel engines worked hard in and near cities - ie from trucks not from cars
(and there's private-air NOx from cookers etc)

as shown in our publicly-subsidised Channel 4 TV - commissioned independent tests around 'Dieselgate'
(these publicised as showing diesel cars to be NOx city-polluting but actually showed the opposite)

so increased takeup of electric cars won't change this

What relation are you doing between diesels and EVs? Explain please, because I see your post as complete nosense

He's saying that as diesel cars didn't appear to be a major source of urban NOx levels...

If that´s what he said then it actually is complete nosense. Around 40% of total cars are diesel (using UK as an example only because that´s first data I found, but it´s similiar in all Europe)
https://www.thisismoney.co.uk/money/car ... efore.html


And each diesel produce 10 times more NOx than each petrol engine
https://www.transportenvironment.org/si ... _FINAL.pdf

So it the opposite, diesel cars are one of the main sources of NOx



If he meant diesel engines produce less NOx than petrol, to then conclude a switch to EV from petrol cars will not reduce NOx, then it is a logical fallacy as obviously petrol cars produce a lot more NOx into the city than EV wich produce zero

Another posibility is he meant diesel engines clean the air (the opposite to NOx city-polluting is cleaning air from NOx), but I don´t think he was saying something this absurd

Andres125sx wrote: ↑

30 Apr 2020, 20:03

Just_a_fan wrote: ↑

30 Apr 2020, 12:28

Andres125sx wrote: ↑

30 Apr 2020, 08:04

What relation are you doing between diesels and EVs? Explain please, because I see your post as complete nosense

He's saying that as diesel cars didn't appear to be a major source of urban NOx levels...

If that´s what he said then it actually is complete nosense. Around 40% of total cars are diesel (using UK as an example only because that´s first data I found, but it´s similiar in all Europe)
https://www.thisismoney.co.uk/money/car ... efore.html


And each diesel produce 10 times more NOx than each petrol engine
https://www.transportenvironment.org/si ... _FINAL.pdf

So it the opposite, diesel cars are one of the main sources of NOx



If he meant diesel engines produce less NOx than petrol, to then conclude a switch to EV from petrol cars will not reduce NOx, then it is a logical fallacy as obviously petrol cars produce a lot more NOx into the city than EV wich produce zero

Another posibility is he meant diesel engines clean the air (the opposite to NOx city-polluting is cleaning air from NOx), but I don´t think he was saying something this absurd

I think he meant that other sources of NOx (not just cars) were simply much higher than Diesel. And that with that fact, EV will not lower the current situation very much.

So now we are going to drift into another Global Warming argument?

How many passenger cars do you see towing anything these days?

I went out to get groceries and some gas so I did an informal survey. Two thirds of the small SUVs and passenger cars I saw had trailer hitches. Audis, VWs, Subaru Impreza's and Outbacks even Mercedes you name it.

One guy living near where I live had fixed one on his Ferrari.

Zynerji wrote: ↑

30 Apr 2020, 20:44

Andres125sx wrote: ↑

30 Apr 2020, 20:03

Just_a_fan wrote: ↑

30 Apr 2020, 12:28

He's saying that as diesel cars didn't appear to be a major source of urban NOx levels...

If that´s what he said then it actually is complete nosense. Around 40% of total cars are diesel (using UK as an example only because that´s first data I found, but it´s similiar in all Europe)
https://www.thisismoney.co.uk/money/car ... efore.html


And each diesel produce 10 times more NOx than each petrol engine
https://www.transportenvironment.org/si ... _FINAL.pdf

So it the opposite, diesel cars are one of the main sources of NOx



If he meant diesel engines produce less NOx than petrol, to then conclude a switch to EV from petrol cars will not reduce NOx, then it is a logical fallacy as obviously petrol cars produce a lot more NOx into the city than EV wich produce zero

Another posibility is he meant diesel engines clean the air (the opposite to NOx city-polluting is cleaning air from NOx), but I don´t think he was saying something this absurd

I think he meant that other sources of NOx (not just cars) were simply much higher than Diesel. And that with that fact, EV will not lower the current situation very much.

Then that´s a perfect example of logical fallacy.

A pollutes a lot, B pollutes but less, C pollutes nothing (into the cities). Swithing from B to C will not reduce pollution becuase B pollutes less than A.

Tommy Cookers wrote: ↑

29 Apr 2020, 18:40

essentially the public-air NOx comes from diesel engines worked hard in and near cities - ie from trucks not from cars
(and there's private-air NOx from cookers etc)

as shown in our publicly-subsidised Channel 4 TV - commissioned independent tests around 'Dieselgate'
(these publicised as showing diesel cars to be NOx city-polluting but actually showed the opposite)

so increased takeup of electric cars won't change this

Here’s some more recent “research”.

London traffic reduced about 75% after lockdown. On Euston Road, (extremely busy dual carriageway just outside the Ultra Low Emission Zone) the NOx levels have roughly halved and the particulate levels have gone up maybe by as much as 50%.



If the 75% were replaced with electric vehicles I would expect the NOx to stay down but the particulates rise further, dependant on the effect of tyre wear and the lifting effect from aerodynamics. This might suggest that domestic particulate generation is influential, which won’t come as a surprise to you.

The pollution data comes from the London Air Quality Network Warning this is not an https site.

https://www.londonair.org.uk/london/as ... dk-djitdk=.