Robert L. McMasters Department of Mechanical Engineering Virginia Military Institute

Robert L. McMastersDepartment of Mechanical Engineering

Virginia Military InstituteLexington, 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

ME 480 - Internal Combustion Engines

Octane Number: 0 – 100 Scale0 = pure n-heptane100 = pure iso-octane

Cetane Number: 0 – 100 Scale0 = 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 rich4HC + 10NO → 4CO2+ 2H2O + 5N2

2CO + 2NO → 2CO2 + N2

If fuel/air mixture is lean4HC + 5O2 → 4CO2 + 2H2O2CO + O2 → 2CO2

Emission Standards

Max allowable grams per mile

CO HC NOx1966 87 8.8 3.61970 34 4.1 4.01974 28 3.0 3.11975 15 1.5 3.11981 7 0.41 1.0

Chapter 4: Spark Ignition Engines

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

Note: MBT is Minimum advance for Best Torque

Chap 5: Compression Ignition

Chap 6: Induction and Exhaust ProcessesThis is best addressed with CFD

Chap 7: Two-stroke EnginesLess efficient but high power density

Chap 8: In Cylinder MotionVarious methods of anemometry

Chap 9: Turbocharging

We can have “suck through” or “blow through” fuel injection

Suck Through:Same pressure, same fuel pumpOnly adjust fuel injection to match increased air flowGood Mixture

Blow Through:Compressor is at same pressure so it won’t suck oilShorter intake path for faster response timeAvoid centrifugal segregation of fuel

Now back to number crunching!