I have two questions related to IC engines. First one is, what will be the maximum temperature obtained inside an combustion chamber? I know it depends on the type, size, charge and many other factors but for theoretical and design heat transfer analysis what temperature can be considered as the maximum in an 100cc Engine?
The second question is, consider the same 100cc engine powered by air cooled gasoline and its Stochi ratio is 14.7:1. During every intake stroke the overall sucked charge will not be equal to the Swept Volume. So what percentage of volume will be filled by the charge? Once again this also comprises of various factors but tell some relative consideration for theoretical simulation purpose.
For your first question, since you know the stoichio ratio you can find the amount of energy released during combustion by multiplying the mass of fuel-air mixture with LCV of fuel. From first law of thermo this energy released will be equal to mass of charge * Cv * (Tf _-Ti) where Tf is the final temperature attained by the charge.
For the second question, you need to know the pressure and temperature at the suction point. Then making the ideal gas assumption you can calculate the volume. This will be the actual volume of air sucked in.
You'll also find this in IC Engine Fundamentals- Heywood
I read Heywood... The task is that it can be found in these cases... But its not a single compound and it is a mixture.. and also with respect to volume we cannot find because if say the volume is 100cc, the whole 100cc will not be filled by the charge... it can't be judged too as 75% of it like that.. and with respect to volume only mass can also be found... instead for finding the volume only i rose this question.. I thought of finding mass from temperature....
sorry in my answer earlier I have made this mistake- the energy released will be mass of fuel * LCV of fuel and regarding what you say of it being a mixture take the Cv of air but at a high temperature (around 1500 C )or write Cv as a function of Tf...even then you'll get fairly accurate results...
From the ideal gas equation you'll find the specific volume V=mRT/P for air
and you should know the mass flow rate of air.
for theoretical estimation of maximum temperature, you can calculate the Adiabatic flame temperature at constant volume for gasoline. This is like the maximum the fuel can ever burn in a const volume combustion condition, which is a good approximation to SI engine combustion.
The air drawn is not equal to the clearance volume. It is equal to vol.efficinecy* swept volume. this drawn volume gets compressed to clearance volume by rising it pressure.
There are always cyclic variations in air drawn. The best approximation would be 0.85 * swept volume.
Theoretically, the adiabatic flame temperature which is the maximum flame temperature in ICEs can be calculated from the relation of complete combustion products's enthalpy and reactants's enthalpy. For the swept volume, is it possible to relate between the fuel conversion efficiency and mean effective pressure?.
ic engine internal temperature vary from 1800 C to 2300 C and may reach up to 2700 C but it may be under overheat condition
Yes I tend to agree with Muhammad Hanif the maximum temperature as reported may reach up to 2500 K.
I recommend for you reading the paper by : Meguerdichian,M. and Watson,N. " Prediction of mixture formation and heat release in diesel engines" SAE paper No. 780225, 1978.
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