What are the processes of Otto cycle?
The Otto cycle consists of isentropic compression, heat addition at constant volume, isentropic expansion, and rejection of heat at constant volume.
What are the major processes in the air-standard Otto cycle?
The Otto cycle is an air-standard cycle which approximates the processes in petrol or diesel engines. It is based on constant volume heat addition (combustion) and heat rejection processes, and isentropic compression and expansion.
Which of the following is the sequence of steps happen in Otto cycle?
Explanation: The correct sequence is intake->compression->expansion->exhaust and expansion stroke is also called power stroke.
What are the four strokes of the Otto cycle?
An internal-combustion engine goes through four strokes: intake, compression, combustion (power), and exhaust.
Which is more efficient Otto or Diesel cycle?
6 Diesel Cycle Although for a given compression ratio the Otto cycle has higher efficiency, because the Diesel engine can be operated to higher compression ratio, the engine can actually have higher efficiency than an Otto cycle when both are operated at compression ratios that might be achieved in practice.
Which is the most efficient cycle?
Carnot cycle
What is the basic difference between an Otto cycle and diesel cycle?
The main difference that separates these two cycles is the way they supply heat to the engine to begin the ignition. Another noteworthy difference is that the Otto cycle heat occurs at constant volume, whereas the diesel cycle works on constant pressure.
Which cycle has highest efficiency?
Explanation: Otto cycle is more efficient than Diesel cycle for a given compression ratio. 6. For constant maximum pressure and heat input, the air standard efficiency of the gas power cycle is in the order.
Why is 100 Efficiency 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.
Why Carnot cycle is not possible?
Carnot cycles are not encountered in reality since achieving isothermal heat transfer is very difficult (needs very large heat exchangers and long time). Also process 3-4 requires a pump or compressor that can handle two phase mixture (liquid and vapor) which is impractical.
What is Carnot cycle used for?
Carnot cycle, in heat engines, ideal cyclical sequence of changes of pressures and temperatures of a fluid, such as a gas used in an engine, conceived early in the 19th century by the French engineer Sadi Carnot. It is used as a standard of performance of all heat engines operating between a high and a low temperature.
What is the principle of Carnot engine?
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 the formula for thermal efficiency?
The thermal efficiency is a dimensionless unit. If you take formulas in thermodynamics, you can get that η= 1- (T COLD/THOT). TCOLD usually represents the ambient temperature where the engine is located. This may just be the temperature outside in whatever environment the engine is at.
What are the two factors of thermal efficiency?
In theory, the factors that affect thermal efficiency (the performance of an engine or the work it has done in relation to the value of heat supplied to it) are the heat input and the heat output. Additionally, temperature variations also come in play, the amount and the rate of losing or gaining heat.
How do you calculate cycle efficiency?
The efficiency of the cycle is obtained by comparing the total work W to the total heat input QIN. β = V4/V3 is the cutoff ratio. (V3 = V2.) γ = CP/CV is the specific heat ratio.
What is thermal efficiency of petrol engine?
Gasoline (petrol) engines Modern gasoline engines have a maximum thermal efficiency of more than 50%, but road legal cars are only about 20% to 35% when used to power a car.
Which engine has highest efficiency?
electric engine
Why thermal efficiency of 4-stroke engine is more than 2 stroke engine?
As far as efficiency goes, the 4-stroke certainly wins. This is due to the fact that fuel is consumed once every 4 strokes. Four-stroke engines are heavier; they weigh upwards of 50% more than a comparable 2stroke engine.