The way I look at it.

If you’ve bought one of the cars in question during the last couple of years, and so far
have been very happy with it. Does it really matter ?

Unless you are a fully paid up member of Friends of the Earth.

It may matter to you if the bottom drops out of the secondhand market for these cars as some are predicting.

If you are an asthmatic like me, you may also have concerns as NOx is a trigger.

This will no doubt be a very ignorant question but if they can manipulate the emissions why isn’t that a standard feature on the car?

I believe the reasons are to do with fuel consumption and ‘driveability’
In full emission reduction mode, such as during the testing, the power is reduced, the engine is much more reluctant to accelerate and also reduces engine braking when the throttle is lifted.

So if/when all these vehicles are modified to match the emissions at all times, they may not be very nice to drive. This is why already a number of people in the US are saying they are worried owners won’t bring the cars in for the fix.

P

I’m not sure you are correct about turbocharging a petrol engine; more power for a given engine capacity certainly but does that translate to lower CO2 (%) emissions if more fuel is being burnt?

the modern way is to use a smaller capacity engine with a turbo to replace a normally aspirated engine. For example, my partners’ 1.2 Tsi Polo has 110 hp and 150lbft of torque, yet uses much less fuel in the real world, not just the ‘official’ figures, than the 1.6 normally aspirated version it replaces, which had 105hp and about 115lbft of torque. It is also much more punchy and nicer to drive in almost every way

This is taking into account the lower friction and pumping losses in the smaller capacity engine so the savings are made when full power is not required, e.g. Steady speeds. The Turbo also allows for excess air to help emissions.
They are starting to use cylinder deactivation to cut the losses even further in steady state conditions-the valves are held shut to reduce pumping losses on the deactivated cylinders I believe- the air compressed on the upstroke acts as a spring on the downstroke, the only losses being hysteresis in heating the trapped air I think.

What I cannot understand is why VW took such a risk when they presumably offer all the affected vehicles with a petrol engine also?

Because the UK market, and I would guess but I’m not sure, the EU market is skewed by the demand for low CO2 emissions. even now, Diesels produce 15%less CO2 fro a given power/torque output although petrol turbo’s are catching up

Disgraceful is inadequate to describe this news item. But then, we have our own homegrown version. Life extending drugs being denied to cancer sufferers on the dubious grounds of cost/benefit but, we can still afford to divert 900 million of the overseas aid budget of 12 billion, to Syria, effectively ignoring the plight of our NHS patients.

There is no link between NHS and Foreign aid budgets as you well know. I would have thought you would be in favour of cost/benefit analysis for NHS treatment as you seem keen to reduce the goverment deficit.

You will have to try harder

It would appear the EPA have been looking into Volkswagen since early 2014! and finely threatened not to approve the affected models for sale next year before Volkswagen came um clean! that’s why Volkswagen have withdrawn them from sale as they no longer meet type approval and to add insult to injury for those that have brought them they cant sell them until the issue is fixed, they probably cant even drive them legally on the road!

I believe the authorities in the US have said that the vehicles can continue to be used and sold on as normal, especially since they will be recalled to ‘fix’ the problem.

VW/Audi can’t sell any new vehicles until it is sorted

The others are claiming they knew nothing. All VW diesels apparently have the gadget fitted. Mine included..

It is not all VAG diesels, it is the 4 cylinder 2L EA 189, produced from 2009 to present. So not the 6 cylinder, 5 cylinder or 3 cylinder engines, nor the PD engines pre 2008.

This is what has been admitted, so far at least.

Still a large number involved

The real problem with Diesels compared to petrols is Nitrogen Oxide emissions NOx

As I understand it, for diesels to pass the NOx tests in California, they have to inject urea into the catalyst- car companies call this system ‘AdBlue’.

http://www.volkswagen.co.uk/technology/diesel/adblue

The AdBlue tanks are a finite size. allegedly the VW system detected when under test, made sure the urea was being injected then when the test was finished it turned the injection down or off to save having to top up the AdBlue so often.

Relatively few cars in the UK use AdBlue, but it seems that other tweaks may have been used on European cars to get good emission results, it is now being reported that 11million vehicles worldwide are affected in some way.