Assignment 2 - Exploring Tutorial No 1- SI final IC Engine Calibration using GT Power
Assignment 2 - Explore Tutorial No 1- SI final (IC Engine Calibration using GT Power)
1. Run the case at 1800 rpm and list down important parameters
Procedure:
Open Tutorial from a given path and save it in a different folder.
Double tap on Engine and change the RPM to 1800.
Results
air flow rate = 24.6 Kg/h
BME = IMEP - FMEP = 10.61 bar - 1.31 bar = 9.48 bar
BSFC = 239.2 g/kW-h
In-cylinder pressure = 48.89 bar
2. Increase the power output at 3600 rpm by 10%
Run the case at 3600 rpm using same procedure used above. The obtained output Brake power = 16.6973 kW(Default case) which is to be increased by 10%
Engine Power or Horsepower is the maximum power that an engine can gives out. The Power output depends on the size and design of the engine, but also on the speed at which it is running and the laod or torque. Maximum power is acheived at relatively high speeds and at high loads.
Power = (Engine Torque x Engine Speed) / 5252
There are following ways by which increasing the power output can be achive
Increasing stroke length
In the above simulation stroke length is increase from 86 t0 100 mm in a vorder of 2 just to see the variation in break power output. Therefore case 1 is a default case whose power output is 16.6838 kW and if we take a look at above table at every change in stroke length the power output is changes. So at case no 6 we get power output 18.4987 kW and if we find out percentage increase in power
% increase in Power output = ((18.4987-16.6838)/16.6838)*100 = 10.87 %
Thus increasing stroke length by 10mm i.e. from 86 mm to 96 mm we get 10% increase in Brake power output.
Increasing bore diameter
From the above resukts we can see that the bore diameter affects the power output a lot. 1 mm change in bore diameter give higher variation in power output. So if we take case no 3 we get brake power = 18.4040 so % increase is
% increase in Power output = ((18.4040-16.6838)/16.6838)*100 = 10.31 %
Just increase in bore diameter by 4 mm we get 10 % Increase in Power output.
Changing compression Ratio
from the above results we can see that there is a increase in power output due to increase in compression ratio but in SI engines generally we use gasoline as a fuel which has less compression ratio and due to compacity of cylender if we increase compression ratio then the problem of knocking arises which is not desirable for a SI engines. Thus increasing Copression ratio to get a higher power output is not practicle.
There are other ways of Increasing the power output giving rich A/F mixture to engine cylender for combustion but again it depends on the time require to burn entire given mixture and if mixture is not burn completely then there is a increase in the formation of exhaust gas which is not environment friendly. Also this method of increasing power leads us to the high fuel consuption.
Then again there is another way to increase power output by increasing no. of cylenders into engine. but again that comes up with space, fuel consuption and engine block weight(which makes vehcle heavier one) isssues also if we are looking for 10% power output then increasing no of cylender is not desirable.
Increase the temperature of the combustion process or change in fuel type also gives us increase in power.