Spark ignition and diesel engineds

Question 1

Otto:

0-1

Answer 1

air draw in at CONSTANT PRESSURE

Question 2

Otto:

1-2

Answer 2

ADIABATIC (isentropic) compression

piston moves from BOTTOM DEAD CENTRE (TDC) to TOP DEAD CENTRE (TDC)

Question 3

Otto:

2-3:

Answer 3

CONSTANT-VOLUME - heat transfer tot he working gas, from an external source while the piston remains at top dead centre
(ignition of fuel)

Question 4

Otto:

4-1

Answer 4

Constant-volume process in which heat is rejected from eh air while the piston is at BDC

Question 5

Otto:

1-0

Answer 5

air is released to the atmosphere in a constant pressure process

Question 6

definition of compression engine

Answer 6

Diesel engine
internal combustionengine
ignition of the fuel which is injected into the combustion chamber is caused by the elevated temperature of the air in the cylinder due to mechanical compression (adiabatic compression).

Question 7

isochoric means

Answer 7

constant volume

Question 8

isobar is a

Answer 8

line of constant pressure

Question 9

with increasing cut off ratio, what else increases/decreases in a diesel engine

Answer 9

efficient decreases

power output increases

Question 10

Dual:

1-2

Answer 10

isentropic compression, piston moves from BDC to TPC so volume decreases and pressure increases, work is put in (-ve) for this process

Question 11

dual:

2-3

Answer 11

heat in at constant volume - isochoric

Question 12

dual:

3-4

Answer 12

heat in at constant pressure- isobaric

Question 13

dual:

4-5

Answer 13

isentropic expansion, piston moves form TDC to BDC therefore volume increase, pressure decreases, the process outputs work

Question 14

dual:

5-1

Answer 14

Rejection of heat at constant volume

Question 15

what is the efficiency of the dual cycle relative to Otto and diesel

Answer 15

it lies between

Question 16

compression ratio (rv) range for practical diesel engines

Answer 16

12 -23

Question 17

Efficiency for a dual cycle

Answer 17

Lies inbetween the otto and diesel cycle at the same compression ratio

Question 18

Diesel cycle 1-2 (pv diagram)

Answer 18

ISENTROPIC compression

Question 19

Diesel cycle 2-3 (pv diagram)

Answer 19

REVERSIBLE constant pressure heating

Question 20

Diesel cycle 3-4 (pv diagram)

Answer 20

ISENTROPIC expansion

Question 21

Diesel cycle 4-1 (pv diagram)

Answer 21

REVERSIBLE constant volume cooling

Question 22

mean effective pressure equation

Answer 22

work done / stroke volume

Question 23

mechanical efficiency equation

Answer 23

Wbrake / Windicated = eta brake / eta indicated