Benzine
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| posted on 4/12/07 at 09:38 PM |
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Efficiency challenge
If you were to create a scratch built car with the aim of being as effecient as possible in terms of mpg, how would you go about it? What kind of mpg
figure do you think you could reach?
I haven't really looked into it but i'm guessing that key things would be weight, tyre width, aerodynamics, engine rpm, fuel type. I know
some might think this is boring but thinking about it interests me  Could you make your own ignition setup/megasquirt that limits rpm so it could
never go above, say, 2000rpm. How far could you take this?
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dan__wright
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| posted on 4/12/07 at 09:41 PM |
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sprint r with a smart 3 pot diesel engine
FREE THE ROADSTER ONE…!!
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Benzine
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| posted on 4/12/07 at 09:47 PM |
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quote:
Originally posted by dan__wright
sprint r with a smart 3 pot diesel engine
What kind of mpg do you think you could get? Wouldn't having an open driver area and exposed tyres reduce efficiency?
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smart51
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| posted on 4/12/07 at 09:58 PM |
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1) as light as possible
2) as aerodynamic as possible
3) as efficient an engine as possible
4) as efficient a transmission as possible
5) tyres with the lowest rolling resistance
an engine's best break specific fuel consumption is often around 3000 RPM for a petrol, so a rev limit of 3500 or 4000 to stop idiots ruining
things.
Diesel contains about 15% more energy per litre than petrol but the extra weight of the engine might take the edge off that a bit.
The smart diesel gets 85 MPG combined
The Citroen C2 diesel gets 68 MPG combined
typical 250cc scooters get 70 MPG (urban)
piaggio's 50cc direct injection 2 stroke gets 98 MPG (urban)
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russbost
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| posted on 4/12/07 at 10:17 PM |
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Took part in the "Shell 1,000 mile to a gallon" contest when in training with Fords about 30 years ago. I can't remember where we
came (3rd???), but we managed about 750MPG!
Didn't go very fast tho'!
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Don't forget Stainless Steel Braided brake hoses, made to your exact requirements in any of around 16 colours.
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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JoelP
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| posted on 4/12/07 at 10:25 PM |
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also include regenerative braking and maybe, its its a city car, a pair of pedals! 
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twybrow
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| posted on 4/12/07 at 10:31 PM |
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From the shell website:
"In 1985, the first European Shell Eco-marathon was held in France and the record was 680 km on a litre of fuel. Today, the recent records are
equivalent to driving from Paris to Beijing with less than 4 litres of gasoline.
Over the years, the fuel economy record has been rapidly improved. The most recent record was set at the 2003 Rockingham event by team Microjoule from
St Sebastien/Loire in France. They achieved a fuel consumption figure of 10,705 miles per gallon - beating the previous record set by the same team in
2001 by nearly 500 mpg. "
So quite a long way is the answer.
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NeilP
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| posted on 4/12/07 at 10:54 PM |
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Yeah, but on the flat - Like to see them hack over the pennines with a green grin on their chops!
If you pay peanuts...
Mentale, yar? Yar, mentale!
Drive it like you stole it!
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Bluemoon
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| posted on 5/12/07 at 09:02 AM |
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linky: http://content.techrepublic.com.com/2346-10878_11-2313-1.html
Dan
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MikeRJ
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| posted on 5/12/07 at 09:08 AM |
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The humble Citroen AX 1.4 Diesel managed over 100mpg between Dover and Barcelona and got itself a place in the Guinness Book of Records for most
economic production car.
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smart51
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| posted on 5/12/07 at 10:23 AM |
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quote:
Originally posted by MikeRJ
The humble Citroen AX 1.4 Diesel managed over 100mpg between Dover and Barcelona and got itself a place in the Guinness Book of Records for most
economic production car.
The Euromix figure for the 1.4D was 67.5 MPG. That's broadly equivelent to 63.0 in the modern combined test. It was the best you could buy at
the time. The modern C2 1.4 TDi beats that by 4 MPG, despite being in a much heavier car.
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iank
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| posted on 5/12/07 at 11:09 AM |
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For a usable road car (not an efficiency go cart) this is the way forward:
http://www.volkswagen.co.uk/press/Lupo_3L_in_Guiness_World_Record
It manages just over 100mpg in normal(ish) driving on real roads. It won't be fast though.
There is a section on in the Vizard book "How to modify your mini" a lot of the things you need to do are similar to performance tuning as
they both rely on improving efficiency.
--
Never argue with an idiot. They drag you down to their level, then beat you with experience.
Anonymous
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smart51
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| posted on 5/12/07 at 11:35 AM |
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The official figure for the lupo 3l was 88 MPG (the 3L class in Germany is for cars that do 3.0 to 3.9 L/100km, not 3.0 litres or less)
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Bob C
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| posted on 5/12/07 at 12:47 PM |
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our greenpower electric cars do ~100 miles in 4 hrs on the charge in 4 batteries, so we effectively have 3/4hp electrical power available.
To put that in perspective - that is the same energy as that contained in 6.6 ounces of petrol.
Our next years car (just building now) is designed for 140 miles. It's being made by yr7 to 11 schoolgirls !!
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hughpinder
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| posted on 5/12/07 at 01:04 PM |
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Look at www.loremo.com - 2 cars in development, one a 2 cyl oil burner, 20 hp , 0-60 in 16 sec, top 100 about 150 mpg, the other a 3 cyl diesel, 0-60
in 10 sec/140mph and 80+mpg.
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Benzine
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| posted on 5/12/07 at 01:50 PM |
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Maybe I should have phrased the question differently... If you were all to build a car that would pass SVA and be driveable day to day (i.e. capable
of 50 or 60 mph), what kind of figure do you think you could make? The lupo surely has lots of excess weight that could be lost etc. Wouldn't
the 100+mpg barrier be easy to pass?
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Ivan
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| posted on 5/12/07 at 02:20 PM |
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quote:
Originally posted by Benzine
Maybe I should have phrased the question differently... If you were all to build a car that would pass SVA and be driveable day to day (i.e. capable
of 50 or 60 mph), what kind of figure do you think you could make? The lupo surely has lots of excess weight that could be lost etc. Wouldn't
the 100+mpg barrier be easy to pass?
If you reduce weght and keep the aerodynamics then yes - I think you will certainly gain mpg in rough proportion to the weight loss provided you
don't use the extra performance. Especially if you lengthen the final drive ratio to suit whilst being mindful of the torque curve and normal
cruising speed.
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