Creation of Ideal Cycles for Internal Combustion Engines

P M V SubbaraoProfessor

Mechanical Engineering Department

Basic Thermodynamic Structure of an Engine…

The Concept of Mobile Power Plant

Fuel (Resource)

Land, Water & Air (Sinks)

Power Plant --Cycle -- Basic Hardware -- Auxiliaries & Controls

The Great Need :Mechanical Power

Carnot’s Theoretical Model for Steam Engine

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w 1

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low

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netCarnot T

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Higher the temperature of heat addition, higher will be the efficiency.Lower the temperature of heat rejection, higher will be the efficiency.Efficiency of a Reversible Engine is independent of work fluid !!!!

Carnot’s Quick Conclusion to Mundane Problem

Primary Hardware to Execute the Cycle Piston in Cylinder System : An Inversion of for bar Mechanism

Impact on Thermodynamics

Basic Geometrical Description:

Alternate Cyclic Operations of Reciprocation Engine

A I R

IntakeStroke

CombustionProducts

ExhaustStroke

Combined Thermo-Fluid Dynamic Cycle

Basic Hardware Eligibility Conditions to accept a Cycle

Thermodynamic Parameters:

Basic Hardware Eligibility Conditions to accept a Cycle

Geometric Parameters:

Carnot Cycle was found to be Impractical….

Need for a Practicable Model Cycle : Mobile Power Units

•Nicolaus Ottowas's first occupation was as a traveling salesman selling tea, coffee, and sugar. •He soon developed an interest in the new technologies of the day and began experimenting with building four-stroke engines.

•After meeting Eugen Langen, a technician and owner of a sugar factory, Otto quit his job, and in 1864, the duo started the world's first engine manufacturing company N.A. Otto & Cie (now DEUTZ AG, Köln). •In 1867, the pair were awarded a Gold Medal at the Paris World Exhibition for their atmospheric gas engine built a year earlier.

Displacement Work Devices : Spark Ignition Engine

A I R

IntakeStroke

FUEL

Ignition

PowerStroke

Fuel/AirMixture

CompressionStroke

CombustionProducts

ExhaustStroke

Displacement Work Devices : Spark Ignition Engine

A I R

IntakeStroke

FUEL

Ignition

PowerStroke

Fuel/AirMixture

CompressionStroke

CombustionProducts

ExhaustStroke

AirTC

BC

Qin Qout

CompressionProcess

Const volume heat addition

Process

ExpansionProcess

Const volume heat rejection

Process

OttoCycle

Active Part of the Innovation

Simplified Thermodynamic Cycles

• Air-standard analysis is used to perform elementary analyses of IC engine cycles.

• Simplifications to the real cycle include:1) Intake and exhaust processes not considered2) Fixed amount of air (ideal gas) for working fluid3) Combustion process not considered4) Engine friction and heat losses not considered5) Specific heats independent of temperature