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Fuel Saving Tips - Introduction

Before we look at some energy saving tips to increase fuel efficiency and get better fuel economy on your driving each day and everyday, here is a question:-

Do you know what your cars fuel consumption is?

The car manufacturers provide some test figures for new cars when they go on sale. You can find yours on www.vcacarfueldata.org.uk and they quote these figures:

  • Urban fuel consumption (mpg) (cold) defined as: The urban test cycle is carried out in a laboratory at an ambient temperature of 20oC to 30oC on a rolling road from a cold start, i.e. the engine has not run for several hours. The cycle consists of a series of accelerations, steady speeds, decelerations and idling. Maximum speed is 31mph (50 km/h), average speed 12 mph (19 km/h) and the distance covered is 2.5 miles (4 km).

  • Extra-urban fuel consumption (mpg) defined as: The extra-urban cycle is conducted immediately following the urban cycle and consists roughly half steady-speed driving and the remainder accelerations, decelerations and some idling. Maximum speed is 75mph (120 km/h), average speed is 39mph (63 km/h) and the distance covered is 4.3 miles (7 km).

  • Combined fuel consumption (mpg) defined as: The combined figure presented is for the urban and the extra-urban cycle together. It is therefore an average of the two other parts of the fuel consumption test, Urban and Extra-urban cycles, weighted by the distance covered in each part.

Does this mean anything?   Anybody?

I drive a V-reg Ford Focus estate with 1.8litre engine and my official figures are:

  • Urban (cold) - 27.2mpg

  • Extra Urban - 46.3mpg

  • Combined - 36.7mpg

So when you ask me what my car's fuel consumption is what do I answer?

Obviously the answer is - "It depends"

It depends on how I drive, what sort of road, what sort of speed, what sort of traffic etc.

Before you can even try to increase the mileage you get for your car your need to know that figure. So what I suggest is that you work it out for YOUR particular situation.

What you have to do is pretty much common sense:

  1. Fill the tank to the brim.
  2. Drive normally; if you do all your miles on the motorway then continue doing that, if you normally drive locally in stop/start traffic then don't change.
  3. When your tanks empty, fill it up again and check the mileage.
  4. Drive normally again until the tanks empty once more, fill up to the brim and note the mileage.

Now just work out the fuel consumption as follows:

 Date  £ paid £ per litre Litres (a) Gallons (b) Miles MPG £/100miles (c)
  filled up 0 0 0 0 0 0
  £40.12 0.819 48.99 10.78 340 31.55 £11.80
  £40.74 0.819 49.75 10.94 255 23.3 £15.98
  £40.51 0.819 49.46 10.88 257  23.62 £15.76
   

Note a. I prefer to stick to Gallons but it's up to you.
Note b. Divide number of litres by 4.546 to get gallons, I'm talking Imperial Gallons here not US Gallons.
Note c. Divide Amount paid by Miles driven and multiply by 100 to get £ per 100 miles.

I like the last figure of £/100miles because it's a nice easy way to understand how much your fuel is costing; whereas MPG is, to my mind, not so easy to understood instinctively. However that's up to you again.

Now; you are going to say to me:-

"Why are the figures so different for the first tankful when you compare them to the second and third ?"

The answer is this:

My normal motoring is very local; lots of stops and starts, lots of stopping the engine and getting out, then getting back in again and re-starting the engine, no long trips at all. This means lots of accelerations and braking, lots of low gear work and lots of waste. The first tank of petrol coincided with a journey of around 240miles (round trip) on main roads and motorways with a smaller proportion of local driving. So I could drive at a steady pace, probably around 75mph on motorways - a bit less on normal roads obviously - you can see the difference the two driving conditions produce.

This longer trip is probably more like the official definition of "Combined Fuel Consumption" Whereas the fuel economy for my normal motoring is close to the "Urban Cold Fuel Consumption" Don't you think that my fuel economy for my "normal" driving is pretty poor?

But stop there! When we say that my normal motoring is all done "cold" and you then compare my figures with the "official" figures they are not that far out:

  • Official "Cold" - 27.2mpg vs Mine - 23.5mpg
  • Official "Combined" - 36.8mpg vs Mine - 31.55mpg

When you talk to any motorist it's very rare to find someone who can get the "Official" manufacturers figures for fuel consumption.

It doesn't take rocket science to understand anything that I'm going to tell you, it's really not complicated.

I'm not going to tell you to start spending money and modifying your car or swapping your present one for a new model. All I'm showing you are the mechanics of driving efficiently and it's EASY! There is HUGE potential saving on your fuel bill.You see, pound-for-pound, nothing gives a better return on investment than you knowing the ways to increase the mileage from your fuel, get better fuel economy and get the most out of your monthly fuel expenses, and...

..it doesn't matter what car you are driving!

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