Most drivers only realize their vehicle is suffering from engine degradation or a failing mass airflow sensor when it completely breaks down. The earliest warning sign of mechanical failure isn't a check engine light; it is a sudden, unexplained drop in fuel efficiency. However, if you are just glancing at your dashboard MPG meter, you are relying on estimated factory software rather than hard physics. To truly measure an engine's health, you need to track the exact volume of fuel consumed against the physical distance traveled. This Memento system acts as a rigid, metric-driven telemetry vault, forcing raw pump data into unassailable financial and efficiency metrics.
Establishing the Physical Baseline
A fuel log is useless if it doesn't establish an absolute distance interval. The template eliminates guesswork by demanding hard odometer readings before any fuel is pumped.
It requires the "Previous Odometer Reading" and the "Current Odometer Reading". A background script instantly subtracts the previous from the current to establish the "Total Kilometres Travelled" for that specific tank of fuel. The system then locks this interval in time and space by automatically generating a "Date and Time" stamp via a now() script, while requiring the user to manually input the specific "Location" of the fuel station. This prevents the user from accidentally mixing up regional fuel purchases.
The Financial Input
Once the physical distance is locked, the system demands the economic reality of the transaction. It requires only two manual inputs at the pump.
The user must enter the exact "Litres Filled" and the total "Cost" (defaulting to INR). Because fuel prices fluctuate wildly between different stations and municipalities, the system uses a script (#{cost} / #{litres filled}) to instantly calculate the exact "Cost of Petrol/Litre" for that specific fill-up. This allows drivers or fleet managers to audit whether specific highway stations are price-gouging compared to their local urban pumps.
The Efficiency Output Matrix
The entire purpose of this database is to generate actionable efficiency metrics without requiring the driver to pull out a calculator at the gas station.
The system takes the hard interval data and the volumetric input to calculate the definitive "Mileage(Kpl)" (Kilometers per Liter) using the formula #{total kilometres travelled} / #{litres filled}. It then provides the ultimate bottom-line financial metric: the "Cost per Kilometre". If a driver sees their Cost per Kilometre spike from 5.00 INR to 6.50 INR over the course of a month, they have indisputable, mathematical proof that their vehicle requires immediate mechanical servicing, long before catastrophic failure occurs.