Question

What do you mean by fuel efficiency? Write it's significance.

Answer 1

Fuel efficiency is a form of thermal efficiency, meaning the efficiency of a process that converts chemical potential energy contained in a carrier fuel into kinetic energy or work. Overall fuel efficiency may vary per device, which in turn may vary per application fuel efficiency, especially fossil fuel power plants or industries dealing withcombustion, such as ammonia production during the Haber process.
In the context of transport, fuel economy is the energy efficiency of a particular vehicle, given as a ratio of distance traveled per unit of fuel consumed.
Fuel consumption is a more accurate measure of a vehicle’s performance because it is a linear relationship while fuel economy leads to distortions in efficiency improvements.
Weight-specific efficiency (efficiency per unit weight) may be stated for freight, and passenger-specific efficiency (vehicle efficiency per passenger).
The fuel efficiency of vehicles can be expressed in more ways:

• Fuel consumption is the amount of fuel used per unit distance; for example, litres per 100 kilometres(L/100 km). In this case, thelowerthe value, the more economic a vehicle is (the less fuel it needs to travel a certain distance); this is the measure generally used across Europe (except the UK, Denmark and The Netherlands - see below), New Zealand, Australia and Canada. Also in Uruguay, Paraguay, Guatemala, Colombia, China, and Madagascar.[citation needed], as also in post-Soviet space.
• Fuel economy is the distance travelled per unit volume of fuel used; for example,kilometres per litre (km/L) or miles per gallon(MPG), where 1 MPG (imperial) ≈ 0.354006 km/L. In this case, the higher the value, the more economic a vehicle is (the more distance it can travel with a certain volume of fuel). This measure is popular in the USA and the UK (mpg), but in Europe, India, Japan, South Korea and Latin America the metric unit km/L is used instead.