Formula for otto cycle ang carnot engine

In summary: TH-TL)/TH *workdoneIn summary, the formula for the Otto cycle includes thermal efficiency, heat added, heat rejection, and mean effective pressure, with the compression ratio being a key factor. For the Carnot engine, the formula involves thermal efficiency, work done, heat added, and temperature and volume calculations.
  • #1
tomoyo_13m
4
0
hi i just want to know the formula of the otto cycle for the folowwing parameter:
compression ratio,cycle work,heat added,heat rejection,thermal efficiency and mean effective pressure.

and also may i know the formula for getting the pressure (bar) and the volume(m3/kg) temperature(K) for carnot engine, the cycle efficiency, heat added and work cycle?

tanx for your help
 
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  • #2
tomoyo_13m said:
hi i just want to know the formula of the otto cycle for the folowwing parameter:
compression ratio,cycle work,heat added,heat rejection,thermal efficiency and mean effective pressure.

and also may i know the formula for getting the pressure (bar) and the volume(m3/kg) temperature(K) for carnot engine, the cycle efficiency, heat added and work cycle?

tanx for your help

formula for otto cycle and carnot engine
otto cycle thermal efficiency = 1- 1/ r^(gamma-1) where r = compression ratio =Cp/Cv
heat added= Cv(T3-T2) kj/Kg
Heat rejected =Cv(T4-T1)KJ/Kg
m e p= Cv[(T3-T2)]-(T4-T1)]/(V1-V2)
Carnot engine thermal efficienc= workdone/heat added = (R ln V3/V2)[Th-Tl]/R Th lnV3/V2
w= [R ln v3/v2][Th-Tl] where Th = highest temp Tl = lowest temp.
efficiency=( TH-TL)/TH
 
  • #3


Sure, I would be happy to provide you with the formulas for the Otto cycle and Carnot engine.

First, let's start with the Otto cycle. The Otto cycle is a thermodynamic cycle that describes the idealized process of a four-stroke internal combustion engine. It consists of two isentropic (constant entropy) processes and two isochoric (constant volume) processes. The formula for the Otto cycle is:

Thermal efficiency (η) = 1 - (1 / compression ratio)^(γ-1)

Where:
- γ is the specific heat ratio of the working fluid (usually air)
- Compression ratio is the ratio of the maximum volume to the minimum volume in the engine

Cycle work (W) = heat added (Qh) - heat rejected (Qc)

Mean effective pressure (Pme) = cycle work (W) / displacement volume

Next, let's move on to the Carnot engine. The Carnot engine is a theoretical engine that operates on the Carnot cycle, which consists of two isothermal (constant temperature) processes and two adiabatic (no heat transfer) processes. The formula for the Carnot engine is:

Cycle efficiency (η) = (Th - Tc) / Th

Where:
- Th is the hot temperature (in Kelvin)
- Tc is the cold temperature (in Kelvin)

Heat added (Qh) = Th * (S2 - S1)

Where:
- S2 is the specific entropy at the hot temperature (Th)
- S1 is the specific entropy at the cold temperature (Tc)

Work cycle (W) = (Th - Tc) * (S2 - S1)

Where:
- Th and Tc are the same as before
- S2 and S1 are the same as before

I hope this helps! Please let me know if you have any further questions.
 

1. What is the difference between the Otto cycle and the Carnot cycle?

The Otto cycle is a thermodynamic cycle used in spark ignition engines, while the Carnot cycle is a theoretical cycle used to represent the maximum efficiency of a heat engine. The main difference between the two is that the Otto cycle operates with a constant volume combustion process, while the Carnot cycle operates with a reversible isothermal process.

2. What is the formula for the Otto cycle?

The formula for the Otto cycle is Q = W + ΔU, where Q is the amount of heat added, W is the work done, and ΔU is the change in internal energy. This formula represents the first law of thermodynamics, which states that energy cannot be created or destroyed, only transferred and transformed.

3. How is the efficiency of an Otto cycle engine calculated?

The efficiency of an Otto cycle engine can be calculated using the formula η = 1 - (1/r)^γ-1, where η is the thermal efficiency, r is the compression ratio, and γ is the ratio of specific heats. This formula represents the theoretical maximum efficiency of an Otto cycle engine.

4. Can the Otto cycle be used in all types of engines?

No, the Otto cycle is specifically used in spark ignition engines, which are commonly found in gasoline-powered cars. Diesel engines, on the other hand, use the diesel cycle which operates with a constant pressure combustion process.

5. What factors affect the efficiency of an Otto cycle engine?

The efficiency of an Otto cycle engine is affected by various factors including the compression ratio, the amount of heat added, and the specific heat ratio. Other factors such as engine design, fuel quality, and operating conditions can also impact the efficiency of the engine.

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