IC Engine Heat Transfer
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Transcript of IC Engine Heat Transfer
Heat Transfer in IC Engine
Prof. Engr. Dr. Mohammad Javed HyderChief Engineer, PIEAS, PAEC
Energy distribution in an
IC engine as a function of engine
speed
Total Power (energy) available in engine
Brake thermal efficiency: (percentage/ fraction of total energy available at crankshaft)
Distribution of energy in an IC engine
Engine
temperatur
es
Piston temperature 4 cylinder, 2.5 liters, SI engine, running at 4600 rpm, WOT
(temperature in oC)
Piston temperature 4 cylinder, 2.5 liters, SI engine, running at 4600 rpm, WOT(temperature in oC)
Piston temperature distribution as a function of engine speed The engine is operating at full load
Engine Warm-up
Variation of engine temperature during the startup of the engine
Heat transfer in Intake system• Walls of the intake manifold are hotter than the flowing gases.
• Gases are heated
• Manifold is hot – By design (exhaust gas, hot coolant, electrical)– By location
• Some systems have hot spot in optimum location• Earlier vaporization => homogeneous mixture• Increased temperature => reduced volumetric efficiency• Supercharging/ Turbocharging => over heating
=> aftercooling
Gas Temperature Variation in side cylinder
Heat transfer in Engine• Heat transfer per unit area
• Heat transfer on the inside surface of the cylinder
• Radiation heat transfer between combustion chamber and cylinder wall
CylinderCombustion Chamber
• In addition to good thermal properties coolant should posses