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ME 480 - Internal Combustion Engines. Robert L. McMasters Department of Mechanical Engineering Virginia Military Institute Lexington, Virginia Textbook: Introduction to Internal Combustion Engines by Richard Stone, Third Edition, SAE 1999 Chap 1: Introduction
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ME 480 - Internal Combustion Engines Robert L. McMasters Department of Mechanical Engineering Virginia Military Institute Lexington, Virginia Textbook: Introduction to Internal Combustion Engines by Richard Stone, Third Edition, SAE 1999 Chap 1: Introduction Chap 2: Thermodynamic Principles Chap 3: Combustion and Fuels Chap 4: Spark Ignition Engines
Octane Number: 0 – 100 Scale 0 = pure n-heptane 100 = pure iso-octane Cetane Number: 0 – 100 Scale 0 = pure α-methylnaphthalene C10H7CH3 100 = pure n-cetane C16H34 Which fuel produces more CO2? Volatility: Changes with the seasons
Catalytic Convertor If fuel/air mixture is rich 4HC + 10NO → 4CO2+ 2H2O + 5N2 2CO + 2NO → 2CO2 + N2 If fuel/air mixture is lean 4HC + 5O2 → 4CO2 + 2H2O 2CO + O2 → 2CO2
Emission Standards Max allowable grams per mile CO HC NOx 1966 87 8.8 3.6 1970 34 4.1 4.0 1974 28 3.0 3.1 1975 15 1.5 3.1 1981 7 0.41 1.0
Definitions Indicated Mean Effective Pressure (IMEP) = indicated work per cycle engine displacement Brake Mean Effective Pressure (BMEP) = brake work per cycle engine displacement Mechanical Efficiency = BMEP/IMEP Volumetric Efficiency = volume of air inhaled engine displacement
Chap 6: Induction and Exhaust Processes • This is best addressed with CFD
Chap 7: Two-stroke Engines • Less efficient but high power density • Chap 8: In Cylinder Motion • Various methods of anemometry • Chap 9: Turbocharging
We can have “suck through” or “blow through” fuel injection • Suck Through: • Same pressure, same fuel pump • Only adjust fuel injection to match increased air flow • Good Mixture • Blow Through: • Compressor is at same pressure so it won’t suck oil • Shorter intake path for faster response time • Avoid centrifugal segregation of fuel