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In mechanical engineering, mechanical efficiency is a dimensionless ratio that measures the efficiency of a mechanism or machine in transforming the power input to the device to power output. A machine is a mechanical linkage in which force is applied at one point, and the force does work moving a load at another point.
For this reason, it is often called the ideal mechanical advantage (IMA). In operation, deflection, friction and wear will reduce the mechanical advantage. The amount of this reduction from the ideal to the actual mechanical advantage (AMA) is defined by a factor called efficiency, a quantity which is determined by experimentation.
The mechanical efficiency of a simple machine is calculated by dividing the actual power output by the ideal power output. This is usually expressed as a percentage. Power loss in a real system can occur in many ways, such as through friction, deformation, wear, heat losses, incomplete chemical conversion, magnetic and electrical losses.
Watt's engine operated with steam at slightly above atmospheric pressure. Watt's improvements increased efficiency by a factor of over 2.5. [16] The lack of general mechanical ability, including skilled mechanics, machine tools, and manufacturing methods, limited the efficiency of actual engines and their design until about 1840. [17]
Mechanical efficiency, where one form of mechanical energy (e.g. potential energy of water) is converted to mechanical energy ; Thermal efficiency or Fuel efficiency, useful heat and/or work output per input energy such as the fuel consumed; 'Total efficiency', e.g., for cogeneration, useful electric power and heat output per fuel energy ...
The four-stroke engine is more efficient when running at full throttle, while the opposite is the case for the two-stroke engine. When a small car under heavy load runs at half speed, the engine automatically switches to the two-cycle mode, which is then more efficient. The research on this showed a 27% reduction in fuel consumption. [8] [9]
Mathematically, it is represented as =, [1] where is the cycle efficiency and is the propulsive efficiency. The cycle efficiency is expressed as the percentage of the heat energy in the fuel that is converted to mechanical energy in the engine, and the propulsive efficiency is expressed as the proportion of the mechanical energy actually used ...
Efficiency is the often measurable ability to avoid making mistakes or wasting materials, energy, efforts, money, and time while performing a task. In a more general sense, it is the ability to do things well, successfully, and without waste.