Gasoline Engine
Draw a P-V diagram for the following cyclic
process:
1)
2)
3)
4)
5)
6)
Isobaric expansion
Adiabatic compression
Isovolumetric heating
Adiabatic expansion
Isovolumetric cooling
Isobaric compression
Gasoline Engine
Efficiency depends on compression ratio:
1
𝑒 =1−
𝑉1 /𝑉2
𝛾−1
Problem 1 (22.71)
1 mole of a monatomic gas is carried through a
Carnot cycle, with a pressures between 1 atm and
25 atm and temperatures between 400 K and 600 K.
a) Draw the P-V diagram.
b) Find P, V, and T at the endpoints of each process.
c) Find the work done by the engine in each cycle.
Problem 2
An ideal diesel engine has the following processes:
1. Heat “enters” via combustion in an isobaric expansion.
2. The gas continues to expand adiabatically.
3. The exhaust valve opens, resulting in isovolumetric
release of heat.
4. The exhaust is pushed out by isobaric compression.
5. New air is brought in by isobaric expansion.
6. The air is compressed adiabatically.
a) Draw a P-V diagram.
b) Verify that the net work of the engine equals the net heat
input.
c) Find the efficiency in terms of the temperatures at the four
“corners” of the P-V cycle.