Question

Define fuel efficiency.

Answer 1

Hint: There are many different types of fuels; some of them have a lot of energy and can be used for a long time with a limited amount of fuel; these are said to have high fuel efficiency. However, certain fuels do not have a sufficient amount of energy, necessitating a large amount of fuel for a shorter period of time; these are referred to as low fuel efficiency fuels.

Complete answer:
When a material comes into contact with oxygen at a temperature equal to or higher than the ignition temperature of the Fuel, it will undergo combustion and emit heat. Any combustible material can be used as a source of energy.
The amount of heat generated by various types of fuels varies. The calorific value of a fuel is used to calculate and express the amount of heat it produces. A high calorific value is needed for a fuel to be classified as good; in other words, the higher the calorific value, the more heat is emitted when that fuel is burned, and vice versa.
As a result, the amount of energy released per unit mass of the fuel can be described as fuel efficiency.
A suitable fuel for automobiles should have a high calorific value, be readily available, and be simple to transport without emitting pollutants.
Vehicles operate on a variety of fuels, including gasoline, diesel, and compressed natural gas (CNG).

 Note:
Some fuels, such as coal, wood, cow dung, and others, are used in villages for heating and cooking, but they have very low fuel efficiency and emit greenhouse gases which are responsible for global warming.