BENG2 THERMODYNAMICS (THER
205)
TUTORIAL EXAMPLES in IC ENGINES 1
(For all questions assume
induction conditions are SSL: 15ºC; 101.325 kPa)
1.
An air
standard Dual cycle commences at a volume of 1 litre and is compressed
adiabatically to a volume of 0.2 litres. Its a value is 1.5
and its b value is 2.5. Find the pressure,
temperature and volume at each of the cycle points 2-5.
[2: 964.4kPa, 548.3K, 0.2 litre;
3: 1446.7kPa, 822.4K, 0.5 litre;
4: 1446.7kPa, 2056.1K, 1 litre;
5: 548.2kPa, 1558.1 K, 1 litre]
2.
An air
standard Otto cycle has a volume compression ratio of 7 and a peak cycle
temperature of 1800ºC. Find the work done per cycle if the cylinder swept volume
is 1.5 litres. [1207.7
J]
3.
An air
standard Diesel cycle has a volume compression ratio of 22.5 and a peak
cycle temperature of 1800ºC. Find the work done per cycle if the cylinder swept
volume is 1.5 litres. [1367.8 J]
4.
If the
maximum cycle temperature for an air standard Otto cycle is 2400ºC and its
volume compression ratio is 9, find the work output per kg of air compressed
during the cycle. [ 833.4 kJ/kg]
5.
A 4-cylinder
petrol engine has a capacity (total swept volume) of 2 litres and the
combustion chamber volume of each cylinder is 60 cm3. Calculate the
air standard efficiency. If the maximum cycle temperature is 1400°C, calculate the IMEP. [0.591, 594.6 kPa]
6.
Using the
same engine as in Q5, find the air standard efficiency and IMEP for a dual cycle
where a is the same as in Q5 above, and b=2. [0.541,
1686 kPa]