GURI SoftHouse
System Development,
Auditing and Consulting

ETHANOL, GASOLINE OU GASEUS


I have read at newspaper, sites, and at some specilized magazines, that if the ratio between prices of Ethanol and Gasoline is 70% or 68% then the best choice for refueling with Gasoline. Is it really true?

No! Unfortunately, NO! The calculation is not "exactly" so simple, since that, today, the car engines are controlled by eletronic injection devices that can adapt, by itself, to operational conditions. Beyond that, there are other important conditions, such as path away, engine speed rotation, traffic jammer, and so far.

The best refuel choice is defined by ratio distance per cost, and not only by prices ratio.

Consider a car with the following performance, or fuel consumption:

At street city, 9.2 Km/L by Ethanol and 11.2 Km/L by Gasoline (1L = 1 Litre).
At road at allowed speed, 9.9 Km/L by Ethanol and 12.3 Km/l by Gasoline.

As you can see, the ratios are not the same for one same fuel at street or road. Those ratios vary from engine to another one.

If we follow the concept of 70% (or any other established by someone) then we would have losses. How much?

Consider the following prices:
Gasoline:
$2.56/L

Ethanol:
$1.79/L


For street at city:
Ethanol:
9.2 Km/L => 9.2/1.79 = 5.13 Km/$ ou 0.195 $/Km.

Gasoline:
11.2Km/L => 11.2/2.56 = 4.38 Km/$ ou 0.229 $/Km.
(Thanks, Carlos!)

It means that my lost is 17% if I refuel with Gasoline for city.

For road:
Ethanol:
9.9 Km/L => 9.9/1.79 = 5.53 Km/$ ou 0.181 $/Km
Gasoline:
12.3 Km/L => 12.3/2.56 = 4.805 Km/$ ou 0.208 $/Km

At streets of city, the losing would be almost 15% by using Gasoline.

So, for a right computation we need also consider the consumption, not ONLY the ratio of prices.

HOW CALCULATE?

Divide the consumption by price, adjusting the units, and takes the highest ratio KM/$ or the smallest $/KM. This defines the fuel.

CALCULATION FORM

After publishing this page, at 2010, I received some messagens requesting a calculation form to show how usefull it is. Well! You will need know what is the consumption (distance per fuel volume) for your car, when it uses Ethanol and Gasoline, and the prices of those fuels at fuel pumb of gas station.

The consuption is the ratio between the distance (registed by odometer) and the fuel quantity, considering a full tank capability.

At assisted gas station, the assistent stops at first click-stop of fuel pump. Under this condition the consumption is incorret.

Some vehicles may store more than 10 Litres (almost 3 galons) after the first click-stop of fuel pump.

ABOUT FORM COMPUTATION

Form Calculation uses the JavaScript language to assist in the choice of fuel.

He "tries" to store the last mileage supplied through cookie and/or feature LocalStorage, implemented in HTML5. However, some users (or administrators) configures the browser to operate in private data mode private (Private Data).

That way, the two forms of temporary storage are remaining active only while the browser is opened.

In the case of Private Data storage off then the mileage supply of the last stand.

WARNING: For security reasons it is NOT RECOMMENDED visit Internet portals with Private Data mode disabled, since it can be used for users tracking and "social statistics".

CONSUMPTION CALC

Use the dot (.) as decimal separator.

GASOLINE

Odometer value at latest (FULL) refueling: (dist.)
Current Odometer value (FULL fueling): (dist.)
Quantity of fuel at current fueling: (vol.)
Mean Consumption Value (dist./vol.)


ETHANOL

Odometer value at latest (FULL) refueling: (dist.)
Current Odometer value (FULL fueling): (dist.)
Quantity of fuel at current fueling: (vol)
Mean Consumption Value (dist/vol)


COMPUTING THE BEST FUEL CHOICE

Consumption ( dist/vol ):

Ethanol:
Gasoline:

Fuel Price ( $ / vol ):
Ethanol:
Gasoline:




Results:



You can use this form at your celular phone without any cost, no banners, no wi-fi, no cel operator data link.

The procedure is simple and works. It was programmed with HTML and Javascript only. The javascript machine of Cel phone navigator must be enabled.
  1. A reduced version, only the form, is available for download, compressed with zip: Consumo-en.zip for comments in English
    Consumo-ptbr.zip for comments in Portuguese-Brazil

  2. Unzip the file at your computer. Use a fresh directory;

  3. Conect your phone cel at your computer using some link (USB, WIFI or any other method).

  4. Create a directpry at SD card of Cel Phone.
  5. Copy the files to the directory of SD card. The following files will be there: Consumo.html and the (optional) picture GuriLogo3.gif, that is the GURI logo.

  6. Open the "File Manager" of your Cel Phone and click over the Consumo.html.pt-br or Consumo.html.en, rename it to Consumo.html, and assume a HTML viewer (navigator).

  7. Have fun! It is the Fuel Choice Calculator.

Feature:


This procedure was tested at following cel phones:

Nokia E71, N85,
Motorola Q11 with Windows Mobile 6.1
Android cels, like as Samsumg S, it works, but at it did not work at Motorola XT321 (Android), even enabling javascript. Although, while visiting the site the page works fine. It means that ANDROID is blocking javascript for local HTML files.

If you have any problem then let me know. You may send a message to :



Your message will be showed here (without e-mail address, of course!) Like you, we also hate spam. By the way, any spam message sent to the email-adress is, automatically, forward to 'abuse' user of your Internet Provider.