CHAPTER 1: ENGINE CLASSIFICATION 

INTRODUCTION 

Internal combustion engines can be classified in a number of different ways:

1. Types of Ignition

((a) Spark Ignition (SI). •

process in each cycle by use of a spark

electric sparkplug, many forms of torch

holes were used to initiate combustion 

electrodes which ignites the air-fuel

plug.The spark plug gives a high-voltage

mixture in the combustion chamber

electrical discharge between two

•An SI engine starts the combustion

surrounding the plug.In early engine

development, before the invention of the electric plug, many forms of torch holes were formed 

from an external flame.

(b) Compression Ignition (CI). •

•The combustion process in a CI engine

starts when the air-cool mixture self-interest 

due to high temperature in the combustion 

chamber caused by high compression 

    CHAPTER 2 

Introduction 

• Engine Block: The main structure containing cylinder bores, pistons, connecting rods, crankshaft, and bearings.
• Cylinder Head: Sits on top of the block, housing the intake/exhaust valves, springs, and spark plugs (or injectors).
• Valvetrain: Includes the camshaft, lifters, and pushrods, which control valve timing.
• Timing System: Gears or chains that synchronize the crankshaft and camshaft, often with the cam sprocket being twice the size of the crank sprocket. 
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• Four-Stroke Cycle (SI/CI Engines):
  1. Intake: Air/fuel mixture or air only is drawn in.
  2. Compression: Mixture is compressed; valves are closed.
  3. Power: Spark ignition (petrol) or compression ignition (diesel) occurs, forcing the piston down.
  4. Exhaust: Burned gases are pushed out.
• TDC/BDC: Top Dead Centre (highest piston position) and Bottom Dead Centre (lowest). 

• Classifications: Classified by stroke (2 or 4), fuel type (petrol/diesel), cooling method (air/water), and cylinder layout.
• Supporting Systems: Fuel systems (carburetor/injection), lubrication, and cooling.
• Performance Metrics: Efficiency improvements (reducing friction/pumping losses) and power output (indicated vs. brake work). 

     CHAPTER 3 

Construction of an internal combustion engine 

Introduction 

ENGINE CONSTRUCTION 

consideration. However, it is Not practical to use for the following reasons:

The stationary parts of an engine include the cylinder block and cylinders, the cylinder 

design considerations and increases production costs.

can be obtained in two-, three-, four-, and six-cylinder in-line models. GM V-type 

1.1.0 Stationary Parts of and Engine

cylinder size, valve arrangement, and so forth. For example, the GM series 71 engines 

horizontally opposed, or V-type. The cylinder block is a solid casting made of cast iron 

lubricating passages, and, in the case of flathead engines, the valves seats, the ports, 

subject to wear. This necessitates the pressing, or casting, of steel sleeves into 

temperatures that air-cooled cylinders obtain. The cylinders have rows of deep fins cast 

lubricated or cooled properly. The cylinders on an air-cooled engine are separate from 

engine will operate determines the type of metal it will be built from.

The construction of an engine varies little, regardless of size and design. The intended 

engines come in 6-, 8-, 12-, and 16- cylinder models.These engines are designed in 

excellent wearing qualities and low material and production cost, and it changes 

framework of the engine. All movable parts are attached to or fitted into this framework.

the cylinder bores. Threaded holes must also be deeper. This introduces extra 

cylinder walls wear out-of-round, or they may become cracked and scored if not 

and the guides. 

dimensions only minimally when heated. Another material used for cylinder blocks, 

The cylinders are bored right into the block. A good cylinder must be round, not varying 

the crankcase. They are made of forged steel. This material is most suitable for 

problems with maintaining tolerances.

1.1.1 Engine Cylinder Block

cylinder must be uniform throughout its entire length. During normal engine operation, 

or aluminum that contains the crankcase, the cylinders, the coolant passages, the 

•Aluminum is more expensive than cast iron.

engine construction and design is toward engine families. Typically, there are several 

in diameter by more than approximately 0.0005 inch (0.012 mm). The diameter of the 

The cylinder block is a one-piece casting usually made of an iron alloy that contains 

such a way that many of the internal parts can be used on any of the models.

The cylinder block is the basic frame of a liquid-cooled engine whether it is in-line, 

•Because of its softness, it cannot be used on any surface of the block that is 

head or heads, and the exhaust and intake manifolds. These parts furnish the 

nickel and molybdenum. This is the best overall material for cylinder blocks. It provides 

1.1.2 Cylinder

To simplify the service parts and servicing procedures in the field, the current trend in 

•Aluminum has a much higher expansion rate than iron when heated. This creates 

types of engines because of the many jobs to be done; however, the service and 

use of the engine determines its size and design, and the temperature at which the 

although not extensively, is aluminum. Aluminum is used whenever weight is a 

•Aluminum is not as strong as cast iron.

service parts problem are simplified by designing engines so they are closely related in 

cylinders because of its excellent wearing qualities and its ability to withstand the high 

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