ME 401: Internal Combustion Engines
This Document is prepared using OCR from the Original Document
Introduction First ICE, an SIE, was developed by Nicolaus Otto in 1876 Rudolph Diesel developed the first CIE in 1892 Engine development has been extraordinary during the last four decades - Issues of air pollution, fuel cost, and market competitiveness have become increasingly important There have been - technical innovation and refinement - construction, configuration and styling - methods of production, and manufacturing systems The internal combustion engine (ICE) is a heat engine that converts chemical energy in fuel into mechanical energy The fuel-air mixture before combustion and the burned products after combustion are the actual fluids The ICEs are generally reciprocating engines - Gas turbine, by definition, is an ICE ICEs can be an SIE or a CIE - Simple, rugged, and has a high power/weight ratio - Wide application in transportation and power generation Engine development saw huge improvements after WWI During the past four decades, new factors have been influencing developments - Air pollution - Noise pollution - Price of fuels There are potentials for further improvements Engine Classifications Internal combustion engines may classified in a variety of different ways - Application Automobile, truck, locomotive, light aircraft, marine, portable power system, power generation - Basic engine design Reciprocating engines (in turn subdivided by arrangement of cylinders: e.g. in-line (straight), V, W, radial, opposed piston and opposed cyinder), rotary engines (Wankel and other geometries) - Working cycle Four-stroke cycle; naturally aspirated (admitting atmospheric air), supercharged and turbocharged, two stroke cycle; crankcase scavenged, supercharged, and turbocharged Page | 1
- Valve or port design and location Overhead (or l-head) valves, underhead (or L-head) valves, rotary valves, cross-scavenged porting (inlet and exhaust ports on opposite sides of cylinder at one end), loop scavenged porting (inlet and exhaust ports on same side of cylinder at one end), through- or uniflow scavenged (inlet and exhaust ports or valves at different ends of cylinder) - Fuels Gasoline (or petrol), fuel oil (or diesel fuel), natural gas, liquid petroleum gas, alcohols (methanol, ethanol), hydrogen, dual fuel, gasohol (90% gasoline. 10% alcohol) - Method of mixture preparation Carburetion fuel injection into the intake ports (PFI) or intake manifold (TBI), fuel injection into the engine cylinder (DI) - Method of ignition Spark ignition (in conventional engines where the mixture is uniform and in stratified charge engines where the mixture is non-uniform), compression ignition (in conventional diesels, as well as ignition in gas engines by pilot injection of fuel oil) - Combustion chamber design Open chamber (many designs: e.g., disc, wedge. hemisphere, bowl-in piston) divided chamber (small and large auxiliary chamber: In any designs; e.g., swirl chamber, prechambers) - Method of load control Throttling of fuel and air flow together so mixture composition is essentially unchanged, control of fuel flow alone, a combustion of these - Method of cooling Water cooled, air cooled, uncooled (other than by natural convection and radiation) Several or all of these classifications can be used at the same time to identify a given engine Thus, a modern engine might be called a turbocharged, reciprocating, spark ignition, four-stroke cycle, overhead valve, water-cooled, gasoline, multipoint fuel-injected, V8 automobile engine
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