IC Engines

Definition: IC Engines studies internal combustion engines, their cycles, performance, fuels, emissions, and advancements in automotive power systems.

Available PYQs:

2018

2022

2024

2025

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Detailed Syllabus

Unit 1: Introduction

• Classification of Internal Combustion Engine
• Parts of I.C. Engine and their materials
• Air standard Cycles in Four stroke and Two-stroke IC engines and their comparative study
• Brayton cycle
• parameters related to testing of IC engines
• determination of volumetric efficiency and factors affecting volumetric efficiency
• Adiabatic flame temperature
• Combustion efficiency
• Valve Timing Diagram
• Low Heat Rejection Engines
• Homogeneous charge compression Ignition

Unit 2: Combustion and Ignition System in SI Engines

• Spark ignition Engine mixture requirements
• Fuel-Air ratio
• Simple carburettor
• Single-point and Multipoint injection system
• Gasoline Direct Injection
• Combustion phenomenon in SI Engines
• Ignition delay
• Flame propagation
• Pressure-Crank angle diagram
• Abnormal combustion
• Auto ignition
• Detonation and Knocking
• Factors affecting combustion and detonation
• Types of combustion chambers

• Working principle of stratified charge engines

• Battery Ignition System
• Magneto Ignition System
• Functions and working of ignition coil
• spark plug
• contact breaker point
• Requirements and working of Ignition advance mechanisms
• Electronic Ignition Systems
• Capacitor Discharge Ignition System
• Transistorized Coil Assisted Ignition System
• Transistor Ignition system with contactless breaker

Unit 3: Fuel Injection and Combustion in CI engines

• Air injection systems
• Airless/solid injection systems
• Common rail
• individual pump
• distributor and unit systems
• Injection pumps
• Fuel injector
• Types of nozzle
• Electronically controlled unit fuel injection system
• Stages of combustion in CI engines
• air fuel ratio
• cold starting of CI engine and cold starting aids
• delay period or ignition lag
• variables effecting delay period
• diesel knock, Factors affecting combustion and knocking
• methods of controlling diesel knock
• Types of CI engine combustion chamber
• Need for supercharging, Effect of supercharging
• types of supercharger, methods of supercharging
• thermodynamic analysis of supercharged engine cycle
• limitations of supercharging, turbocharging

Unit 4: Lubrication system and cooling system

• Types of lubricants and their properties
• SAE rating of lubricants
• Types of lubrication systems – wet sump and dry sump
• crankcase ventilation
• Necessity of engine cooling
• disadvantages of overcooling
• Cooling systems and their comparison: Air cooling, Liquid cooling

Unit 5: Alternative Fuels

• Alcohol - Hydrogen - Natural Gas and Liquefied Petroleum Gas
• Biodiesel- Biogas - Producer Gas
• Properties - Suitability
• Engine Modifications
• Merits and Demerits as fuels, comparison of their properties with Diesel and petrol
• method of manufacturing

Unit 6: Emissions and Control

• Air pollution due to IC engines
• Constituents of exhaust emission at its harmful effect on environment and human health
• Formation of NOx, HC, CO and particulate emissions
• Methods of controlling emissions
• Catalytic convertors
• particulate traps
• Exhaust Gas Recirculation
• EURO and BHARAT norms