What are the two formulas for mechanical advantage?
(b) The ideal mechanical advantage equals the length of the effort arm divided by the length of the resistance arm of a lever. In general, the IMA = the resistance force, Fr, divided by the effort force, Fe. IMA also equals the distance over which the effort is applied, de, divided by the distance the load travels, dr.
How do you calculate work efficiency?
To calculate the efficiency, divide the standard labor hours by the actual amount of time worked and multiply by 100. The closer the final number is to 100, the more effective your employees are.
Why is it impossible to get an efficiency above 1?
It is not possible to have an efficiency of greater than 1 or an efficiency percentage greater than 100%. This would mean that more energy is being transferred than is being supplied, which would mean that energy is being created. This would break the law of conservation of energy.
Why 100% efficiency is impossible?
It is impossible for heat engines to achieve 100% thermal efficiency () according to the Second law of thermodynamics. This is impossible because some waste heat is always produced produced in a heat engine, shown in Figure 1 by the term.
Can efficiency ever exceed 100%?
In other words, no machine can be more than 100% efficient. Machines cannot multiply energy or work input. If a machine were 100% efficient then it can’t have any energy losses to friction, so no friction can be present.
What is the efficiency of Carnot cycle?
It is well known that the Carnot cycle efficiency ( η thermal = 1 − T L T H ) is maximized with the highest possible heat source temperature TH and the lowest possible heat sink temperature TL.
What is Carnot principle?
Carnot’s theorem states that all heat engines between two heat reservoirs are less efficient than a Carnot heat engine operating between the same reservoirs. Every Carnot heat engine between a pair of heat reservoirs is equally efficient, regardless of the working substance employed or the operation details.
What is cycle efficiency?
The Process Cycle Efficiency, sometimes referred to as the “Value Added Ratio,” is a measurement of the amount of value-added time in a process. The higher the number, the more efficient the process becomes. Material often spends 95 percent of its time in waiting.
What is the efficiency of Otto cycle?
Variation of the normalized power output and the thermal efficiency of the irreversible Otto cycle with the compression ratio, γ = 1.4, ηcom = 0.85, and ηexp = 0.90.
What is the principle of Otto cycle?
The first person to build a working four-stroke engine, a stationary engine using a coal gas-air mixture for fuel (a gas engine), was German engineer Nicolaus Otto. This is why the four-stroke principle today is commonly known as the Otto cycle and four-stroke engines using spark plugs often are called Otto engines.
What is the use of Otto cycle?
The Otto Cycle, describes how heat engines turn gasoline into motion. Like other thermodynamic cycles, this cycle turns chemical energy into thermal energy and then into motion. The Otto cycle describes how internal combustion engines (that use gasoline) work, like automobiles and lawn mowers.
How can we increase the efficiency of Otto cycle?
- Run the engine fuel-lean, that is, use excess air. It is well known that fuel-lean running improves the efficiency.
- Higher compression ratio.
- We need new cycles put into practical use.
- Run the engine at optimum conditions, meaning low friction (modest engine speed) and low pumping work (air throttle more open).
Which fuel is used in Otto cycle?
gasoline2
What is the most efficient engine?
Wärtsilä 31SG
Is there a difference between an Otto cycle and a 4 cycle?
While the original Otto cycle engine used gasoline as a fuel source, diesel engines use the same 4-cycle operation through mixing a fuel/air mixture, fuel compression, downward combustion and exhaust. The difference being a diesel fuel/air mixture is ignited by compression instead of a spark.