To ask an engineering question please visit our forum site at Eng-Tips.



Browse our archive of questions and answers below or to access our old forum database of over 10000 questions and answers please visit the old Ask@ forum.

fuel consumption for a car help.
Last Post 21 Mar 2012 09:13 AM by ZuberAli. 2 Replies.
AddThis - Bookmarking and Sharing Button Printer Friendly
  •  
  •  
  •  
  •  
  •  
Sort:
PrevPrev NextNext
You are not authorized to post a reply.
Author Messages
ZuberAli
New Member
New Member
Posts:5

--
19 Mar 2012 06:57 PM
    Hi Guys ive been trying to work out the fuel consumption for a car. i worked it out as below can you confirm if its correct or incorrect asap.

    ive been told by someone that they thinks its not possible to work out fuel consumption over a distance in KWh and has to be done in only KW, but i think you can. lemme know if im right or wrong please.

    range is 488 miles
    4.2L of petrol consumed every 100km, equivelant to 0.042L in 1km therefore i found 1.6km in a mile so i worked out 0.0672L petrol consumed in a mile .

    converted this value into British Thermal Units.
    27533 BTU in one litre of petrol therefore in 1 mile this is
    0.672L x 27535=1850 BTU.

    coverting to watt-hours, i found 0.293Wh in one BTU therfore,
    0.293x1850 = 0.54205KWh in one mile

    changing for 20 miles
    0.54205 x 20=264.5204KWh

    i then adjusted this value for 70% efficiency losses at got a final answer of around 80KWh for 488 miles

    is this correct, can i have my final answer in KWh or does in have to be in watts.

    Thanks
    Niel
    Basic Member
    Basic Member
    Posts:193

    --
    20 Mar 2012 05:55 AM
    KW is a rate of energy flow.

    KWH or Kilowatt Hour is a measure of work.

    If you car is traveling a distance of 488 miles you need to know the work necessary to accomplish that task.

    If you want to know the average rate of consumption you need to divide total work by the amount of time. Let's assume that the vehicle as traveling at 70 miles per hour. As a result the total time is approximately 7 hours.

    80 KWH over seven hours means that the rated of energy flow is 11.6 KW or approximately 15.4 hp.


    Niel Leon
    engineering.com
    ZuberAli
    New Member
    New Member
    Posts:5

    --
    21 Mar 2012 09:13 AM
    thanksd neil,
    just realised i wrote the question wrong, i already know the fuel consumption rate, its 4.2l per 100km.

    i wanted to know how much ENERGY is produced from gasoline after a journey of 488 miles at a fuel consumption rate of 4.2l per 100km

    and is this value in kwh or just kw
    You are not authorized to post a reply.