Thermodynamics: Adiabatic Process, Carnot Cycle, Four Stroke Engine

Name
Instructor
Course
Date
Thermodynamics
Problem 1
Adiabatic means there is no transfer of heat
∆u=Q+W
∆u=3/2nR∆T
W=3/2 nR (Tf-Ti)
PiVi=PoVo
Relationship between pressure and temperature is an adiabatic process
The process in which heat energy of a system is often constant is termed as an adiabatic process
In the PV relation, we can remove the volume with regard to temperature so that we get the
needed relation
PV8=constant
PV=RT
V=RT/P
P (RT/P) 8=constant

P1R8T8/P8=Constant
P1-8T8=Constant/R8=Constant
(P1/P2)8-1= (T1/T2)8
Problem 2
Given that T1=300⁰C=300+273=573K
T2=200⁰C=200+273=473K
Given it is a Carnot cycle;
The efficiency of Carnot cycle
ηcarnot =1−T 1
T 2
=1− 473
573 =0.1754
ηcarnot =17.54 %
Note:
In the problem, the temperatures given, I considered as in degrees Celsius as units have not been
given
In case they are in kelvin
ηcarnot =1−T 1
T 2
1− 200
300 =33.33 %

In the problem given, one should give either Q1 & Q2 only then W can be determined
The problem does not provide the value hence the relation between Q1 and Q2 may be
determined and not the individual values of Q1 and Q2
∴ ηcarnot =1− T 1
T 2
= Q1−Q2
Q1
∴ Q1−Q2
Q1
=0.3333 ≫Q1−Q2=0.333 Q1
∴Q2=0.666 Q1
Work done, W= Q1−Q2=Q1−0.6 66 Q1
Problem 3
A four stroke engine defines internal combustion engine which makes use of four distinct piston
strokes including intake, exhaust, power as well as compression to finish a single operating
cycle. The piston makes double full pass in cylinder in to finish an operating cycle (Lug et al.,
2018). The compression stroke is at the point when mixture of air and fuel trapped is compressed
within cylinder and combustion chamber is normally covered to generate a charge that is of
compressed mixture volume of air and fuel that is trapped within combustion chamber in
readiness for ignition.
The intake event occurs at the interdiction of air/fuel mixture into combustion chamber. The
event of intake occurs upon piston moving from TDC to BDC with valve for intake is left open
(Zhou et al., 2016). The piston movement in the direction of BDC produces low pressure within
cylinder and ambient atmospheric pressure pushes air-fuel mixture into cylinder via open intake
and thus filling low pressure area generated by movement of piston.