GHG Emissions

[Coby1]

Hi All,

There is an article this week in my weekly magazine that talks about green house gas emissions in a way that even an idiot like me can understand:

it refers to GHG emissions, in this case CO2, in terms of grammes per kilometre (g/km).

Is there anyone on this forum who can talk to me in such a clear and unequivocal way, about the knackering of my fuel consumption by emissions controls please?

[Krikkit]

You found a weird example of a restricted bike that improved economy afterwards, that doesn't mean it applies everywhere.

What do you actually want to know?

[anonymous-user]

Krikkit said:

You found a weird example of a restricted bike that improved economy afterwards, that doesn't mean it applies everywhere.

Given that the OPs claimed differences actually break the laws of physics, i'm going to suggest something else is actually going on.......

[Krikkit]

Max_Torque said:

Given that the OPs claimed differences actually break the laws of physics, i'm going to suggest something else is actually going on.......

Yeah I was glossing over the madness really in the hope we could have some fun, you spoilt it

[Coby1]

Well Chaps,

I guess I would like to see some figures for GHG emissions; and know how those figures where calculated.

If those calculations begin with;
we burned off 10 litres of fuel and measured the GHG emissions coming out of the tail pipe...

then go on to say;
we then multiplied the measured GHG emissions by the amount of kilometres per litre of fuel....


I swear that I will strangle someone!

[normalbloke]

Coby1 said:

Well Chaps,

I guess I would like to see some figures for GHG emissions; and know how those figures where calculated.

If those calculations begin with;
we burned off 10 litres of fuel and measured the GHG emissions coming out of the tail pipe...

then go on to say;
we then multiplied the measured GHG emissions by the amount of kilometres per litre of fuel....


I swear that I will strangle someone!

Ask VW.

[Coby1]

It's a fairly simple equation, but if no-one has factored in 25-33% extra fuel use these figures could be very misleading!

As petrol-heads I would have thought this would concern you more than most.

[Krikkit]

You've got it backwards, they don't burn a set amount of fuel, they push the car through a set and repeatable test sequence and ask for the results of a gas analysis of the exhaust. From that they use formulas to calculate a representative single figure that's then used for tax purposes.

The details are here: https://circabc.europa.eu/sd/a/02b0a5e2-e328-44e3-...

[WatchfulEye]

Coby1 said:

Hi All,

There is an article this week in my weekly magazine that talks about green house gas emissions in a way that even an idiot like me can understand:

it refers to GHG emissions, in this case CO2, in terms of grammes per kilometre (g/km).

Is there anyone on this forum who can talk to me in such a clear and unequivocal way, about the knackering of my fuel consumption by emissions controls please?

You are mixing up two things. First, there is CO2, which is a measure of fuel consumption; second, there are regulated emissions, which are toxic substances.

1 litre of petrol, when burned, releases 2.3 kg of CO2. So, if your car does 10 litres per 100 km (28 MPG in British customary units), then it will emit 230 g CO2 per km. In principle, it can be measured in the exhaust, but it can also be calculated from the fuel consumption - whichever method is used should give the same answer, because CO2 is simply a surrogate for fuel consumption (unless the fuel changes). Although, given that the exhaust has to be analysed during a test cycle for regulated emissions (see below), it makes sense to also analyse it for CO2 to get a direct measure.

The regulated emissions are things like nitrogen oxides (NOx), hydrocarbons, carbon monoxide and particulate matter.These are all toxic and unpleasant substances which are responsible for significant respiratory illness (worsening of asthma, for example). Emissions control equipment on cars is used to control these. On petrol cars, catalytic converters deal with NOx, hydrocarbons and carbon monoxide, with the GPFs used to control particulates under the latest regulations; On diesel cars, EGR systems and selective catalytic reduction (adblue) are used to control NOx, with DPFs used to control particulates.

On petrol cars, the effect on fuel consumption (CO2) is limited. On diesel cars, regeneration of DPFs can increase fuel consumption.

Edited by WatchfulEye on Wednesday 20th May 18:35

[kerplunk]

WatchfulEye said:

1 litre of petrol, when burned, releases 2.3 kg of CO2.

It's a nitpick but I can't resist. Better to say produces than releases - two thirds of that 2.3kg came from the atmosphere.

[LimSlip]

Coby1 said:

It's a fairly simple equation, but if no-one has factored in 25-33% extra fuel use these figures could be very misleading!

As petrol-heads I would have thought this would concern you more than most.

Why are you so utterly obsessed with emissions? Your bike was restricted for licencing purposes, NOT FOR EMISSIONS. Far more interesting is why your (apparent) economy has changed by unrestricting it, but that has ZERO to do with emissions legislation.