I know from previous posts (esp the one on global warming) that some of you are rather more intelligent than I. As such, I'd appreciate some of your help on some calculations I'm trying to do. I've had the Prius working as a cab one year on November 3rd, 2010 and I'm wanting to do a little report on how good it is on fuel economy and emissions to show the local taxi inspector. I'm poor at maths so I'd be grateful for someone to check my figures are correct and also convert them into percentages etc. Please remember the gallons are UK gallons which is 4.54 liters compared to 3.8 liters for a US gallon! Now my average consumption so far (as you can see from my fuelly) is coming in at 49.2 UK mpg. Now over 34,100 miles (will probably 35k by 11/3/10) that works out at 711 UK gallons? Which at an average cost of say £1.15 a litre works out at 3228 litres or £3,710 a year. This is pretty much close to what I got in reality. Now how do I show how many metric tonnes of CO2 I have saved compared to a car doing 40 mpg, 35 mpg, 30 mpg & 25 mpg in costings AND percentage savings? Also, I want to show the savings of NOx compared to say a modern diesel engined taxi (UK Mondeo diesel?) on the above mpg's (40, 35 etc) and then I'd like to show how this equates if say 100 of the 500 taxis in our town suddenly became Prius's overnight etc. There was a recent article in the local paper saying that the town failed on NOx pollution in certain parts and I'm sure if more taxis were Prii, then this might not be so bad. Of course the 10 year old smoggy buses in town don't help any! I told you I'm no good at maths - if I was, I know I wouldn't be driving a cab round for a living! lol. Can anyone who isn't arithmetically challenged like me help do the above sums for me so I can have my presentation ready for the cabs annual birthday in November? Cheers Guys & Guyettes.
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.
Ok the other car comes in at about 30 mpg with a NOx of 216 mg/Nox/km compared to 6mg/Nox/km for the Euro Prius.
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.
In that case I must be Canadian too. Being follically challenged I will often be seen sporting a 'tuque', though it is known by a different name over here. Getting back to subject though......?
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 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. ---- 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.
Thanks for the above. I think this shows the problems I'm having though as there isn't a like for like comparison between petrol and diesel models. Also, I understand that some figures are quoted in micro grams and others in milli grams which could make a big difference.
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
