While these terms are often used interchangeably, they have subtle differences:

Fuel Efficiency:

• This is a broader term representing how effectively a vehicle or engine converts fuel into energy for movement. It encompasses various factors like engine technology, vehicle design, aerodynamics, and driving behavior.
• A more fuel-efficient vehicle uses less fuel to travel the same distance compared to a less efficient one.

Fuel Consumption:

• This specifically refers to the amount of fuel used by a vehicle over a certain distance. It’s typically measured in litres per 100 kilometers (L/100km) or miles per gallon (MPG).
• A lower fuel consumption indicates the vehicle uses less fuel per unit of distance, directly impacting fuel costs.

Fuel Economy:

• Similar to fuel consumption, fuel economy also denotes the rate at which fuel is used. However, it’s expressed as the distance traveled per unit of fuel, like kilometers per litre (km/L) or miles per gallon (MPG).
• A higher fuel economy signifies the vehicle can travel further with the same amount of fuel, again reflecting greater efficiency.

Rate per 100 litres:

• This is simply the reciprocal of fuel consumption (L/100km). It tells you the distance traveled using 100 litres of fuel.
• While less commonly used, this can be another way to compare fuel efficiency, with a higher rate per 100 litres indicating better efficiency.

Relationship between the terms:

• Fuel efficiency directly impacts both fuel consumption and fuel economy. A more efficient vehicle will inherently have lower fuel consumption and higher fuel economy.
• Fuel consumption and fuel economy are essentially two sides of the same coin, just expressed differently.

In summary:

• Fuel efficiency: Overall effectiveness of fuel usage.
• Fuel consumption: Amount of fuel used per distance.
• Fuel economy: Distance traveled per unit of fuel.
• Rate per 100 litres: Distance traveled using 100 litres of fuel.