Introduction

The main components of an engine system can be divided into two major parts. The Engine Bottom End and the Engine Top End. The design and components of engine may varies with the type of engine and number of cylinders, but the basic components and their functions are basically the same.

Figure 1. Engine Basic Components

 

Engine Bottom End Construction

The term engine bottom end generally refers to the engine block or cylinder block which consists of engine cylinder, crankshaft, connecting rod, pistons, water jacket and related components.

Engine cylinder is a round holes that fixed inside cylinder block. The piston fit into the cylinders. Piston diameter is slightly smaller than the cylinder to lets the pistons slide up and down freely. Pistons transfer the force of expanding combustion gases to the connecting rods. They are made of aluminum to reduce weight. Most engine pistons have compression rings and oil ring.

Oil and coolant passages through the engine block allow lubrication and cooling of the cylinder head parts.
Water jackets are coolant passages through the block. They allow a water and antifreeze solution to cool the cylinders.

Figure 2. Engine Bottom End Construction-1

 

Figure 3. Engine Bottom End Construction-2

 

 

 

 

Engine Top End Construction

The term engine top end generally refers to the cylinder heads, valve, camshaft, and other related components. These parts work together to control the flow of air and fuel into the engine cylinders. They also control the flow of exhaust out of the engine.

Figure 4. Engine Top End Construction-1

Figure 5. Engine Top End Construction-2

Engine Front End Construction

The Engine Front End operates the engine camshaft, alternator, water pump, distributor and cooling fan. Basically, the engine front end consists of a drive mechanism for the camshaft and other devices, a front cover, an oil seal, and crankshaft damper.

Figure 6. Engine Front End Construction-1

 

Figure 7. Engine Front End Construction-2

 

 

 

Fuel System Parts

Figure 8. Gasoline Engine Fuel Parts

 

Electrical System Parts

  

Starting Motor

The starting system provides an easy method of starting the engine. The electric starting motor is designed to crank the engine with the simple turn of a key.

Figure 9. Starting Motor Parts

Charging System Parts

An alternator has function to charge battery and power the engine/car electrical system. During engine cranking, the battery supplies all electricity. Then, when the engine starts running, the charging system takes over to provide current to the car’s electrical systems and the battery is recharged. The engine crankshaft pulley and alternator belt spins the alternator pulley. This powers the alternator and causes it to produce electricity.

The voltage regulator keeps alternator output at a preset charging voltage (approximately 13 to 15 volts). Since this is HIGHER than battery voltage (12 Volt), current flows back into the battery and recharges it. Current also flows to the ignition system, electronic fuel injection system, on-board computer, radio, or any other device using electricity.

Figure 10. Charging System Parts

Ignition System Parts

The car's ignition system produces high voltage needed to ignite the fuel charges in the cylinders of a gasoline engine. The system must create an electric arc across the gaps at the spark plugs. These events must be timed so they happen exactly as each piston nears the top of its compression stroke. The heat of each spark starts combustion and produces the engine's power strokes. In recent years, different types ignition systems have been developed to improve engine performance, fuel economy, and dependability.

Ignition Coil Part

An ignition coil produces the high voltage (30,000 volts or more) needed to make current jump the gap at the spark plugs. It is a pulse type transformer capable of producing a short burst of high voltage for starting combustion. Coil output voltage usually passes through the coil wire, distributor, plug wire, and spark plug before starting the burning process in the engine.

The ignition coil consists of two sets of windings (insulated wire wrapped in circular pattern). The coil has two primary terminals (low voltages connections), an iron core (long piece of iron inside windings), and a high voltage terminal (output or coil wire connection).

The primary windings of the coil are several hundred turns of heavy wire, wrapped around or near the secondary windings. The secondary windings are several thousand turns of very fine wire located inside or near the primary windings. Both windings are wrapped around an iron core and are housed inside the coil case.

Figure 11. An Ignition Coil Parts

 

Ignition Distributor Part

Typically, an ignition distributor has several functions:

1. It actuates the ON/OFF cycles of current flow through the ignition coil primary windings.

2. It distributes the coil's high voltage pulses to each spark plug wire.

3. It must cause the spark to occur at each plug earlier in the compression stroke as engine speed increases and vice versa.

4. It changes spark timing with changes in engine load. As more load is placed on the engine, the spark timing must occur later in the compression stroke to prevent spark knock (abnormal combustion).

5. Sometimes, the bottom of the distributor shaft powers the engine oil pump.

6. Some distributors (unitized distributors) house the ignition coil and electronic switching circuit.

Figure 12. An Ignition Distributor Parts

 

Cooling System Parts

The Basic parts of a cooling system are water pump (forces coolant through engine and other system parts), radiator hoses (connect engine to radiator), radiator (transfer engine coolant heat to outside air), Fan (draws air through radiator) and thermostat (controls coolant flow engine operating temperature).

When the engine is running, a fan belt powers the water pump. The water pump forces coolant to circulate through the engine water jackets. While the engine is cold, the thermostat remains closed. This prevents coolant from going to the radiator. Instead, it circulates around inside the engine. This helps warm the engine quickly.

When the engine reaches operating temperature, the thermostat opens. Heated coolant heat is transferred to the air flowing through the radiator. This maintains a proper engine temperature.

Figure 13. Water Cooling Systems

Lubrication System Parts

The lubrication system is extremely important to engine service life because it forces oil to high friction points in engine. Without a lubrication system, friction between parts would destroy an engine very quickly. Many of the engine parts would rapidly overheat and score from this friction. Engine bearings, piston rings, cylinder walls, and other components could be ruined.

With the engine running, the oil pump pulls motor oil out of the oil pan.

A screen on the pickup tube removes large particles from the oil before oil enters the pump. The pump then pushes the oil through the oil filter and oil galleries.

The oil filter cleans the oil, removing very small particles. The filtered oil then flows to the camshaft, crankshaft, lifters, and other moving parts. When oil leaks out of the engine bearings, it sprays on the outside of internal engine parts. For example, when oil leaks out of the connecting rod bearings, it sprays on the cylinder walls. This lubricates the piston rings, pistons, wrist pins, and cylinders. Oil finally drains back into the oil pan for recirculation.

Figure 14. An Oil Filter Parts