What is constant in an Otto cycle?
Otto cycle Thermodynamics. 1. an ideal thermodynamic combustion cycle, as follows: a compression at constant entropy; a constant-volume heat transfer to the system; an expansion at constant entropy; and a constant-volume heat transfer from the system.
What is the formula of Otto cycle?
When we rewrite the expression for thermal efficiency using the compression ratio, we conclude the air-standard Otto cycle thermal efficiency is a function of compression ratio and κ = cp/cv.
What is the formula for compression R ratio of the Otto cycle?
Explanation: This is the expression for efficiency of Otto cycle and rk=compression ratio=Vmax/Vmin.
Is Otto cycle constant pressure?
Process 4-1: Heat rejection at constant volume….Explanation:
| Otto Cycle | Constant volume heat rejection. Constant volume heat addition. |
|---|---|
| Diesel Cycle | Constant pressure heat addition. Constant volume heat rejection. |
| Dual Cycle | Constant volume and constant pressure heat addition Constant volume heat rejection |
Why is there constant volume heat in Otto cycle?
As is well known, the constant volume heat addition cycle, which is often referred to as the Otto cycle, considers one special case of an internal combustion engine, whose combustion is so rapid that the piston does not move during the combustion process, and thus combustion is assumed to take place at constant volume …
Why is the Otto cycle engine called a constant volume engine?
S.I engine Diesel cycle is called constant pressure cycle because the heat addition process in diesel cycle is done at constant pressure whereas petrol cycle is called constant volume cycle (Otto Cycle) as here the heat addition is done at constant volume. (Heat rejection in both the cycles is done at constant volume).
What is air standard efficiency of Otto cycle?
The maximum pressure in the engine is around 55.2 Mpa and thermal efficiency of engine is around 66.2%.
What is the relation between compression ratio r?
Whenever the value of compression ratio is more it means the compression of the gas inside the cylinder of the engine (petrol) would be more. The value of the compression ratio for the Otto cycle cannot be increased more due to the knocking problem.
What is the relation between compression R?
The compression ratio (CR) is defined as the ratio of the volume of the cylinder and its head space (including the pre-combustion chamber, if present) when the piston is at the bottom of its stroke to the volume of the head space when the piston is at the top of its travel (‘top dead centre’, tdc).
How does the ideal Diesel cycle differ from the ideal Otto cycle?
The most significant difference between the ideal Otto cycle and the ideal Diesel cycle is the method of igniting the fuel-air mixture. Recall that in the ideal Diesel cycle the extremely high compression ratio (around 18:1) allows the air to reach the ignition temperature of the fuel.
What is the ideal compression ratio of an Otto cycle that uses air as the gas and has an efficiency of 50 %?
The mean effective pressure (MEP). 9-35 An ideal Otto cycle with air as the working fluid has a compression ratio of 9.5. The highest pressure and temperature in the cycle, the amount of heat transferred, the thermal efficiency, and the mean effective pressure are to be determined.
Which is the constant volume engine?
S.I engine (Heat rejection in both the cycles is done at constant volume). Petrol engines works on Otto Cycle, petrol engines are also called as S.I. Engines.
What is the air standard efficiency of Otto cycle if the clearance volume is 20 of the swept volume?
What is the efficiency of an ideal air standard otto cycle if the clearance volume is 20% of the swept volume? Efficiency of otto cycle = 1 – (frac{1}{6^{1.4-1}} )=0.511=51.1%.
What is the effect of compression ratio on efficiency of Otto cycle?
As the compression ratio increases, the fuel mixture is sufficiently compressed thereby increasing the thermal efficiency, so that less fuel is required to produce the same amount of energy. Fuel consumption is reduced at higher compression ratios between 8 and 9.
What is r in Diesel cycle?
In Diesel cycle, heat is input from the constant pressure cycle. The thermal efficiency of the ideal Diesel cycle is: where r is the compression ratio and rc is the cutoff ratio. In Diesel cycle, process 1-2 is isentropic compression process.
What is the relation between compression ratio and?
Who is the heat added in the Otto cycle?
Through the combustion of fuel, heat is added in a constant volume (isochoric process) process, followed by an adiabatic expansion process power (C) stroke. The cycle is closed by the exhaust (D) stroke, characterized by isochoric cooling and isobaric compression processes.