Outline of Calculation.

Eco Eco INDEX Calculator is a useful evaluation tool that compares the car cost which is sum of both the car price and the its fuel consumption.
Eco Eco INDEX Calculator works among alternative fuel vehicles(except ethanol vehicle), advanced technology vehicles, and conventional vehicles currently on the market.
Eco Eco INDEX Calculation is summarized in the following equations,
Cost per Mile = (Car price + Total fuel cost – Projected resale car price) ÷ Total mileage

The international patent PCT/JP2011/068021 related to the system has been already filed. In the preliminary examination request in October 2012, it was judged to be patentable.

The calculation shows 5 useful information as its result.
1) Eco Eco INDEX: $ / mile = (Car price + Total fuel cost – Projected resale car price) ÷ Total mileage
2) Cost for total energy consumption to drive projected total mileage. It leads to "Promoting efficient consumption of energy".
3) Total car cost which is the sum of both the car price and the total energy consumption. It leads to "Promoting consumers’ selection of the best balance between car price and technologies of saving energy" .
4) Projected resale car price. It leads to "Knowing accurate car cost".
5) Total CO2 emission during projected total mileage. It leads to "Promoting emission reduction".

Vehicle Data
A user selects vehicles to compare by model year, make, and model. For each vehicle selected, the calculator withdraws the Car price (MSRP) and the Fuel economy (city, highway and combined) from the database.

Driver Behavior Information
In order to accurately calculate total fuel costs for selected vehicles, it is significant to know how a user drives and how much of the vehicle's total mileage is driven using each fuel type.
In order to know the important information, 3 queries below are set up at top page.
* How many miles do you drive for a day?
* How many days do you drive for a week?
* How many years do you plan to drive the car?

Fuel Prices
The fuel type and price is shown below the 3 queries. The prices are based on a national average, as reported in the quarterly Alternative Fuel Price Report. The user may change the fuel price to reflect local prices.

The elements used in the calculation.

(1) Car price: MSRP: Manufacturer's Suggested Retail Price.
(2) MPG: Mile per gallon.
* For Gasoline car, Hybrid car and Diesel car, Combined is used as the MPG.
Combined fuel economy is a weighted average of City and Highway MPG values that is calculated by weighting the City value by 55% and the Highway value by 45%.
* For EV (Electric vehicle), kWh/100miles is used as the MPG. (“kWh/100miles” reads “kWh/1mile”)
* For PHEV (Plug-in hybrid vehicle), Combined（Gasoline） and kWh/100miles (Electricity) are used as the MPG.
(3) Projected total mileage.
Projected total mileage is calculated as follows.
“How many miles do you drive for a day?” (Miles per day) ×　“How many days do you drive for a week? (Driving days per week) ×　52.177457（weeks per year） ×　“How many years do you plan to drive the car?” (Period of car ownership) = Total mileage.
(4)  Projected resale price.
Please note, the projected resale price is calculated as a reference price.
While the car resale price estimating is so complicated, the resale price predicting is calculated with simple method as follows.
Step1： Regarding useful age of vehicle, it is set 15 years as the point at which the resale price of the car would be $ 0.
Step2: Regarding mileage, it is set 150,000 miles as the point at which the resale price of the car would be $ 0.
With using above 15 years, Resale price A is calculated as follows.
Resale price A (based on age) = MSRP x (1 – Period of car ownership ÷ 15)
With using above 150,000 miles, Resale price M is calculated as follows.
Resale price M (based on mileage) = MSRP x (1 – Projected total mileage ÷ 150,000)
Step3: From either resale price A or M, the lower resale price is selected as an approximate resale price.
(5) Period of car ownership
Period of car ownership is shown by one of above query "How many years do you plan to drive the car?".

Calculation of Eco Eco INDEX: Cost per Mile.

(1)  Calculation for Gasoline Vehicle. (Hybrid and Diesel are calculated same as Gasoline vehicle.) 

A calculation for instance with the condition below.

Car Price:MSRP	MPG: Combined	Miles per day	Driving days per week	Weeks per year	Fuel Price: gasoline	Period of car ownership
20,000	20	35	5	52.177457	3.55	10

1) Total Fuel Cost is calculated as follows.
step1: Calculate Total mileage.
35 Miles per day × 5 Driving days per week × 52.177457 Weeks per year × 10 Period of car ownership = 91,311miles
step2: Calculate Total Fuel Cost.
91,311 Total mileage ÷　20 MPG ×　3.55 Fuel Price = $ 16,208-
2) Resale Car Price is projected as follows.
Resale price (M) based on mileage : $ 20,000 × ( 1 - 91,311 miles ÷ 150,000 miles ) = $ 7,825-
Resale price (A) based on age: $ 20,000 × ( 1 – 10 Period of car ownership ÷ 15 Years ) = $6,667-
Select the lower value from ether (A) or (M). Projected resale car price is $6,667-
3) Eco Eco INDEX is calculated as follows.
( 20,000 MSRP - 6,667 Resale price + 16,208 Total fuel cost ) ÷ 91,311 Total mileage = $ 0.32/ mile

EV's calculation method is the almost same as Gasoline vehicle except fuel price.

(2) Calculation for Plug-in hybrid

A calculation for instance with the condition below.

Car Price: MSRP	kWh/100miles	MPG: Combined	Miles per day	Driving days per week
30,000	29	20	35	5

Weeks per year	Period of car ownership	All electric range	Fuel Price: electricity	Fuel Price: gasoline
52.177457	10	21	0.12	3.55

1) How to calculate Total Fuel Cost of Plug-in hybrid.
* Calculate method of Total Fuel Cost.
If the Miles per day is equal or smaller than the All electric range(Driving range, Total Fuel Cost is calculated with only using electricity fuel.
If the Miles per day is bigger than the All electric range, Total Fuel Cost is calculated with using both electricity fuel and gasoline.
Step1: Compare Miles per day and the All electric range.
In this case, Miles per day 35 > the All electric range 21.
Step2: Calculate Total mail age of both using electricity fuel and gasoline.
Step2-1: Calculate Total mileage of using only electricity fuel.
21 All electric range × 5 Driving days per week × 52.177457 Weeks per year × 10 Period of car ownership = 54,786 miles(E)
Step2-2: Calculate Total mail age of using only gasoline.
(35 Miles per day - 21 All electric range) × 5 Driving days per week × 52.177457 Weeks per year × 10 Period of car ownership = 36,524 miles(G)
*And the sum of both mileage =91,311
Step3: Calculate total fuel cost of using electricity fuel. Note the condition of the calculation: At the start of driving, electric drive mode is always selected until the battery runs out .
54,786 miles(E) × 29 kWh/100miles ÷ 100 × 0.12 Fuel Price(electricity) = $ 1,907-
Step4: Calculate total fuel cost of using gasoline.
36,524 miles(G) ÷ 20 combined × 3.55 Fuel Price(gasoline) = $ 6,483-
* Total fuel cost that sum of both electricity fuel + gasoline = $ 8,390-

2) Calculate Projected resale price.
Resale price (M) based on mileage : $ 30,000 × ( 1 - 91,311 miles ÷ 150,000 miles ) = $ 11,738-
Resale price (A) based on age: $ 30,000 × ( 1 – 10 Period of car ownership ÷ 15 Years ) = $10,000-
Select the lower value from ether (A) or (M). Projected resale car price is $10,000-
3) Eco Eco INDEX is calculated as follows.
( 30,000 MSRP - 10,000 Resale price + 8,390 Total fuel cost ) ÷ 91,311 Total mileage = $ 0.31/ mile

In the two calculation above, $ 30,000 PHEV is more economical than $ 20,000 Gasoline vehicle in this case.
This program allows such simulations and comparisons.
Hope you enjoy it.