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Explore the development of internal combustion engines from horse anatomy to Carnot's theory, detailing ideal cycles and thermodynamic models. Discover the foundations for modern engine design!
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Creation of Ideal Cycles for Internal Combustion Engines P M V Subbarao Professor Mechanical Engineering Department Basic Thermodynamic Structure of an Artificial Horse (Engine)…
Anatomy of A Horse : Result of Nearly 40000 years of Evolution
The Routine of A Horse (Natural or Artificial) • Inhalation of fresh air. • Intake of diet. • Compression of air. • Digestion of intake with air. • Generation of Mechanical Motion. • Exhalation of waste. • A cyclic creature called natural air breathing Engine. • Actions are discrete but final outcome is continuous.
Development of Artificial Horse Fuel (Resource) Power Plant --Cycle -- Basic Hardware -- Auxiliaries & Controls The Great Need : Mechanical Power Land, Water & Air (Sinks)
Scientific Development of Engine • 1698 – Thomas Savery Steam Engine (A positive displacement type Control Mass device). • 1712 – New Comen Steam Engine(A positive displacement type Control Mass device). • 1769 – James Watts Steam Engine(A positive displacement type Control Mass device) • 1824 – Carnot Theory.
Sadi Nicolas Léonard Carnot • 1821: Carnot began the work which led to the mathematical theory of heat and helped start the modern theory of thermodynamics. • The problem occupying Carnot was how to design good steam engines. • Steam power already had many uses - draining water from mines, excavating ports and rivers, forging iron, grinding grain, and spinning and weaving cloth - but it was inefficient.
Carnot’s Thinking • It irked Carnot particularly that the British had progressed so far through the genius of a few engineers who lacked formal scientific education. • British engineers had also accumulated and published reliable data about the efficiency of many types of engines under actual running conditions. • They vigorously argued the merits of low- and high-pressure engines and of single-cylinder and multi-cylinder engines. • 1822 – 1823 : Carnot attempted to find a mathematical expression for the work produced by one kilogram of steam. • Carnot's work is distinguished for his careful, clear analysis of the units and concepts employed and for his use of both an adiabatic working stage and an isothermal stage in which work is consumed. • 1824 : Réflexions sur la puissance motrice du feu et sur les machines propres à développer cette puissance which includes his description of the "Carnot cycle".
expansion Heat Addition Heat Removal A Mathematical Model for (James Watt’s) Steam Engine
The Ideal Gas Engine • 1824: Sadi Carnot, who founded the science of thermodynamics, identified several fundamental ideas that would be incorporated in later internal combustion engines: • He noted that air compressed by a ratio of 15 to 1 would be hot enough (200°C) to ignite dry wood. • He recommended compressing the air before combustion. Fuel could then be added by "an easily invented injector". • Carnot realized that the cylinder walls would require cooling to permit continuous operation. • Later, Diesel thought he could avoid this, but found out the hard way. • He noted that usable heat would be available in the exhaust, and recommended passing it under a water boiler.
Thermodynamic Modeling : A tradition of Post Carnot Research • Major portion of motive power generation occurs in any Reciprocating IC engine in a control mass (closed system). • The thermal operation of any IC engine is a transient cyclic process. • Even at constant load and speed, the value of thermodynamic parameters at any location vary with time. • Each event may get repeated again and again. • So, an IC engine operation is a transient process which gets completed in a known or required Cycle time. • Higher the speed of the engine, lower will be the Cycle time. • Modeling of IC engine process can be carried out in many ways. • Multidimensional, Transient Flow and heat transfer Model. • Thermodynamic Transient Model USUF. • Fuel-air Thermodynamic Model. • Air standard Thermodynamic Model.