Download - Kuliah 1 Introduction- Ice
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KM30803 APPLIED THERMODYNAMICS
DEFINITION OF ENGINE
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KM30803 APPLIED THERMODYNAMICS
INTRODUCTION TO ENGINE (ICE)
Definition of Engine
Definition of Heat Engine
External and Internal Combustion Engine
Basic Engine Component
Nomenclature
The Working Principle of Engine, four stroke/ two stroke
FUEL AIR CYCLE AND THEIR ANALYSIS
Fuel Air Cycles and their Significance
Composition of Cylinder Gases
Variable Specific Heat
MEASUREMENT AND TESTING IN ICE
Introduction
Indicated power
Brake power
Fuel consumption
Air consumption
Speed
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KM30803 APPLIED THERMODYNAMICS
An engine is a device that transforms one form ofenergy into another form.
Efficiency of conversion plays an important role intransformation of energy
Normally, most of the engines convert thermalenergy into mechanical energy/work and they arecalled heat engines (transforms chemical energy offuel into thermal and utilizes thermal energy foruseful work).
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KM30803 APPLIED THERMODYNAMICS
CHEMICAL ENERGY IS CONVERTED INTOTHERMAL ENERGY BY COMBUSTION
THERMAL ENERGY IS CONVERTED INTOMECHANICAL ENERGY
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KM30803 APPLIED THERMODYNAMICS
PURPOSE
THE PRODUCTION OF MECHANICAL
POWER FROM THE CHEMICAL ENERGY
CONTAINED IN THE FUEL
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KM30803 APPLIED THERMODYNAMICS
EXTERNAL AND INTERNAL ENGINE
Combustion is the act of burning. Internal means inside or enclosed. Thus, in internal combustion engines, the burning of fuel takes place inside the engine; that is, burning takes place within the same cylinder that produces energy to turn the crankshaft.
In external combustion engines, such as steam engines, the burning of fuel takes place outside the engine. Figure in next slides shows, in the simplified form, an external and an internal combustion engine.
The external combustion engine contains a boiler that holds water. Heat applied to the boiler causes the water to boil, which, in turn, produces steam. The steam passes into the engine cylinder under pressure and forces the piston to move downward.
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KM30803 APPLIED THERMODYNAMICS
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KM30803 APPLIED THERMODYNAMICS
EXTERNAL
COMBUSTION ENGINE
STEAM LOCOMOTIVE
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KM30803 APPLIED THERMODYNAMICS
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KM30803 APPLIED THERMODYNAMICS
INTERNALCOMBUSTION ENGINE
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KM30803 APPLIED THERMODYNAMICS
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KM30803 APPLIED THERMODYNAMICS
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KM30803 APPLIED THERMODYNAMICS
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KM30803 APPLIED THERMODYNAMICS
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KM30803 APPLIED THERMODYNAMICS
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KM30803 APPLIED THERMODYNAMICS
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KM30803 APPLIED THERMODYNAMICS
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KM30803 APPLIED THERMODYNAMICS
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KM30803 APPLIED THERMODYNAMICS
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KM30803 APPLIED THERMODYNAMICS
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KM30803 APPLIED THERMODYNAMICS
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KM30803 APPLIED THERMODYNAMICS
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KM30803 APPLIED THERMODYNAMICS
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KM30803 APPLIED THERMODYNAMICS
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KM30803 APPLIED THERMODYNAMICS
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KM30803 APPLIED THERMODYNAMICS
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KM30803 APPLIED THERMODYNAMICS
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KM30803 APPLIED THERMODYNAMICS
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KM30803 APPLIED THERMODYNAMICS
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KM30803 APPLIED THERMODYNAMICS
ENGINE CLASSIFICATION
1.Based on ignition type
a. SI
b. CI
2.Engine cycle
a. Four stroke cycle
b. Two stroke cycle
Three and six stoke cycles were also tried earlier
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KM30803 APPLIED THERMODYNAMICS
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KM30803 APPLIED THERMODYNAMICS
4 Stroke SI engine
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KM30803 APPLIED THERMODYNAMICS
Four-Stroke Diesel Engine
A-Intake stroke Intake valve open, exhaust
valve shut Piston travels from TDC to BDC Air drawn in
B-Compression stroke Intake and exhaust valves shut Piston travels from BDC to TDC Temperature and pressure of
air increase
C-Power stroke Intake and exhaust valves shut Fuel injected into cylinder and
ignites Piston forced from TDC to BDC
D-Exhaust stroke Intake valve shut, exhaust
valve open Piston moves from BDC to TDC Combustion gases expelled
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KM30803 APPLIED THERMODYNAMICS
4 Stroke CI engine - Diesel
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KM30803 APPLIED THERMODYNAMICS
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KM30803 APPLIED THERMODYNAMICS
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KM30803 APPLIED THERMODYNAMICS
Two Stroke Spark Ignition Engines
Stroke 1: Fuel-air mixture is introduced into the cylinder and is then
compressed, combustion initiated at the end of the stroke
Stroke 2: Combustion products expand doing work and then
exhausted
Power is delivered to the crankshaft on every revolution
Application
Small Engines Absence of valve mechanism makes cheaper, compact and lighter engines
Large Engines That operates at a low RPM. Requires a power stroke from every revolution for smooth operation.
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KM30803 APPLIED THERMODYNAMICS
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KM30803 APPLIED THERMODYNAMICS
2 Stroke SI engine
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KM30803 APPLIED THERMODYNAMICS
In two stroke engines the
crankcase is a pressurization
chamber to force fuel/oil/air
into the cylinder. Here, we mix
oil and gas to lubricate internal
parts.
In four stroke engines the
crankcase is separate from the
compression chamber. This
allows the use of heavy oil for
lubrication.
The engines do not last as long
due to poor lubrication.
Increased heating due to more
number of strokes limits the
maximum speed.
The engines do not use fuel
efficiently.
These engines produce a lot of
pollution.
Greater cooling & lubrication
requirements
Power output is only more than
30 % and not doubled