Question

4) A four stroke cycle oil engine has the following data: Mean effective pressure 550 kPa, Swept volume 15L, Speed of the engine 6 revolutions per second, effective brake load 80 kg, effective brake radius 1 m, Fuel consumption 8 kg/h and calorific value of fuel 40 MJ/kg. Determine Indicated power, Brake power, Mechanical efficiency and Indicated thermal efficiency.

Answer 1

Concept:

Indicated power is the power generated by the engine. It is denoted by 'I.P.'

The mean effective pressure (MEP) measures an engine's ability to perform work independently of engine displacement. It is a parameter related to the functioning of a reciprocating engine. When expressed as an indicated mean effective pressure (IMEP), it is possible to think of it as the average force applied on a piston during many cycles.

The formula for the Indicated power is:

I.P.= $P_{im}$×$V_{s}$ ×n

where, Pim is the mean effective pressure while Vs is the swept volume and n is the number of strokes N/2 for four strokes and N for two strokes.

N=RPM

The formula for Brake power is:

B.P.=$\frac{2πNT}{60}$

where T=Torque

Mechanical Efficiency =I.P./B.P.

ηth= $\frac{I.P.}{m_{f}CV }$

Given:

Pim= 550 KPa

Vs= 15 L

n= 6/2= 3

Find:

I.P., B.P.,  ηth, ηmech

Solution:

Putting alll the values in the formula:

I.P. = $5.5$×$10^{5}$×15×$10^{-3}$×$3$=24750 W= 24.75 KW

B.P.= 1507.2 W=1.51 KW

ηmech=6.10%

ηth=46.4%

Hence, above are all the correct answers.

#SPJ3

Answer 2

Concept introduction:

Explanation:

Final answer:

#SPJ3