Fuelinefficiency

Fuelinefficiency is the condition in which energy contained in fuels is not efficiently converted into useful work, causing higher fuel consumption for a given output. It can occur in transportation, electricity generation, and industrial processes, and is commonly described by the amount of fuel required per unit of service, or by energy losses within a system. The term encompasses both design limitations and operating practices that waste energy as heat, friction, or unused exhaust.

Causes include thermodynamic losses during combustion, mechanical friction, parasitic losses from pumps and auxiliaries, aerodynamic drag, and heat losses through exhaust and cooling systems. Poor maintenance, suboptimal engine timing, incorrect fuel-air ratio, and the use of oversized or heavy equipment also contribute. Real-world operating conditions often reduce theoretical efficiency further.

Measurement and indicators include fuel economy metrics (such as liters per 100 kilometers or miles per gallon), specific fuel consumption, and energy intensity. Laboratory tests may overstate efficiency relative to real-world conditions, due to test cycles not reflecting typical driving or load. Standards and testing cycles vary by region and sector, influencing comparisons of performance.

Fuelinefficiency has economic and environmental impacts, increasing fuel costs, reducing energy security, and elevating emissions of carbon dioxide and air pollutants. It can also affect vehicle range, reliability, and the viability of energy-intensive industries.

Mitigation approaches focus on increasing conversion efficiency and reducing energy losses. Examples include advanced engine designs, hybridization and electrification, weight reduction, improved aerodynamics, waste-heat recovery, and optimized operation and maintenance. Policy measures such as efficiency standards, fuel economy targets, and incentives can drive improvements across sectors.