Help Required - I'm No Good At Math

21 or 48.

First you need to find out what the CO2 output of the car is... and if you are comparing to other cars... what is their output.

 

Around here pretty much every cab is a Prius and from talking to cabbies, the reason is not just fuel consumption or tailpipe emissions. Other factors that you may want to think about and mention in your report are:

Brakes
Due to regenerative braking, the brake pads last a phenomenal time. This cuts brake dust pollution as well as downtime and cost.

Maintenance Costs and Downtime
The costs and downtime for service and problems are far less than with other cars they have used. Apart from the straight cost savings, this translates to more time on the road earning money.

Durability
Fewer problems with issues like broken door handles and fittings mean that the car stays in better condition as well as saving the cost and time to fix them.

Passenger Leg room
The Prius rear seat leg room is better than in many of the much larger cars they used to use.

Luggage Space
Luggage space has worked out fine even for those used to full size American carts. To help fit multiple large suitcases with a full passenger load, some cabbies take out the removeable cover over the storage tray and leave it in the garage.

Quietness
Quieter for the cabbie, the passengers, and the public at large

 

Oh gosh, we are dealing with metric units... I am out.

Good thing the weekend is coming up... something to do.

 

Yeah eh? I like beer and wear a tuque.

 

OK Here is a converter for MPG in UK to CO2 in g/km for gasoline.

Convert miles per gallon(UK) to grams of CO2 per km (Gasoline) - fuel consumption conversions online - UnitJuggler

so 49.2 MPG UK is 133.2 g/km of CO2 35,000 miles is about 56,000 km so about 7460000 grams of CO2 or

7.5 Metric tonnes at 49.2 MPG UK

40 MPG is 163.84g/km of CO2 by the same 56,000 km for

9.2 Metric tonnes at 40 MPG UK

30 MPG is 218.45 g/km of CO2 by the same 56,000 km for

12.2 Metric tonnes at 30 MPG UK

25 MPG is 262.14 g/km of CO2 by the same 56,000 km for

14.7 Metric tonnes at 25 MPG UK

(this makes sense 25 MPG is half the mileage, so twice the CO2 generated)

 

US EPA tells me that burning 1 US gallon of gasoline results in 10.4 pounds of CO2 (note - CO2 not carbon). A range of other values can be found elsewhere but that'll do.

It does not matter in which car engine the burning happens, as far as CO2 production.

When I make those units metric, I get 2.32 kilograms of CO2 per liter of petrol (gasoline). Is this enough to get your calculations rolling?

Jimbo won the foot race, and took things a bit further. You could see if my conversion factor confirms.

 

TOYOTA Prius Continuously Variable Mark III 1.8 VVT-i Hybrid 15in wheel [2009] CO2 Emissions & Ratings At What Green Car

This site lists the Gen III with 15" tyres as NOx: 0.006 HC: 0.058 = 0.064 combined.

FORD Mondeo Manual 6-speed 2.0 Duratorq TDCI 115PS Saloon ECO [from July 2009 CO2 Emissions & Ratings At What Green Car

Only lists a combined HC+NOx: 0.164 (2.5 times more) Since I can't find a legend, I have no idea what the units are, to multiply by your mileage. For any mileage, however, the Prius is emitting 1/4 of what the Mondeo is, of HC+NOx.

 

I hate to argue with the EPA, but this is wrong. Closer to 21.3 pounds of CO2 per US gallon.

 

Issue addressed so post removed

 

I suggest starting with amount/km of each pollutant, and then multiplying by distance driven in km for total of each pollutant for each car. The UK labels show Nox and NMOG emissions I think.

The UK states that the Prius emits 89 grams/km CO2 on their cycle, yielding 75 mpg. If you get 49 mpg, then your Prius is emitting (75/49)*89 grams/km. If car 'B' is getting Y mpg, it is emitting (75/Y)*89 grams/km. This is true for petrol cars. You can fudge diesels by multiplying the result by 1.08, or just grab a diesel result and apply the same method.

Total absolute savings: Subtract Prius from Car 'B' for each pollutant.

Percentage savings:
(1) (Car 'b'/Prius - 1)*100 is percentage emissions higher than a Prius;
(2) (Prius/Car-'b')*100 is Prius emissions as fraction of Car-b emissions, as in "Prius emits 11% the Nox as car-b"

Cars taken off the road equivalent:
This will vary by pollutant. Take (1/(Prius/Car-'b')) - 1.

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You write as well as my daughter, cannot be much worse at maths, and she will likely end up being a bloody lawyer. So I say you had a choice, but make the smart one!

btw, best hint of the day, courtesy of Google which will do amazing unit conversions in the blink of an eye using the search box. E.g., type '400000 grams in metric tonnes' and google responds with '0.4'. Google can even understand compound conversions sometimes. E.g., try '0.5 grams/km in pounds/foot.' Google knows the answer, but here you have to hit return to get the result.

 

I made the changes, thanks.

 

Is this well to wheel or just tank to wheel ?

 

This is the 'not math' part of the problem, I am much more familiar with the EPA's website here in the US, I have no idea the name of the corresponding agency in the UK, nor do I have bookmarks linking me to the raw test results on their site. If the Mondeo diesel was used unchanged in the US, I could find it on the EPA website, but it is not. So I lack numbers to 'do math' on.

By the way my conversion of MPG UK to CO2 g/km for gasoline, would be different for a Diesel. The website I linked would do that as well.

 

GrumpyCabbie

Would it not be easier just to sit in a Pub have a beer and watch a Football game

I hate to see you hurt your head