Internal Combustion Engines

Student Name: Student Class Number:

1- (A) The following data of a four stroke engine is known as:

Piston area (A)

Stroke length (L)

Number of cylinders (n)

Indicated mean effective pressure (imep)

Engine rpm (N)

Engine mechanical efficiency (h _m)

- Write down the following quantities using the above symbols:

* The engine swept volume (V_e)

* The work done per one revolution (W_in)

* The engine indicated power (P_b)

2- What are the units of the following physical quantities?

Force

Volume

Work

Torque

3- Write down the engine classifications:
*
*
*
*
*

4-A) What are the differences between the following?

a- SI and CI engines

b- Power and pressure

c- Morse method and motoring method to test the engine

B) What are the engines classifications form the point of view of:

i- Valve locations:

ii- Cylinder arrangements:

5-a) Identify the following thermal process shown in cycle A:
1-2
2-3
3-4
4-1

5-b) What is the difference in the work done between the cycle A and cycle B if points 1,3 are the same and point 2 becomes point 4 and pint 4 becomes point 2.

6- a) Show the following on the figure:
* the work in:
* the work out:
* the heat in:
* the heat out:
6- b) Write down the cycle efficiency:

7- A law speed diesel engine operating on the constant cycle has a compression ratio (r) of 20:1. Air temperature and pressure before compression are (p1) 110 k Pa abs. and (T1) 40 ^oC, respectively. The temperature after combustion (T3) was 1450 ^oC. Find the temperatures and pressures at the main points in the cycle if the volume at point 1 (V1) is 400 cm^3, and g for the gasses is 1.4.