Internal Combustion Engine (ICE) Performance

1
Internal Combustion Engine (ICE) Performance

• ME 252
• Thermal Fluid Systems
• G. Kallio

2
ICE Performance Measures

• Indicated work power work based upon the
  recorded cylinder P vs. V diagram (Otto?ideal
  work)
• where
• Wcycle,net net work per cylinder per complete
  cycle
• n number of cylinders
• ? crankshaft rotational speed (rev/s)
• N number of crankshaft revolutions per
  complete cycle ( 2 for 4-stroke, 1 for
  2-stroke)

3
ICE Performance Measures, cont.

• Mean effective pressure (mep) the average
  pressure, if acted upon by the piston during the
  entire power stroke, that would produce the
  actual net work
• Brake work power output of engine under load,
  usually measured at flywheel by a dynamometer it
  is less than indicated power due to friction and
  parasitic loads

4
ICE Performance Measures, cont.

• Mechanical efficiency (?m)
• Volumetric efficiency (?v)

5
ICE Performance Measures, cont.

• Specific fuel consumption (sfc)