2. 2
Diesel Engine Basics
The purpose of the training
Work we have done there:
Working principle
Diesel Engine Process
Operation and Maintenance
Terminology
Components
Classification
3. 3
Working Principle
Working Principle :
A reciprocating engine, in the cylinders of which
an introduced charge of air is compressed
sufficiently to ensure spontaneous ignition and
combustion of an atomized stream of fuel injected
into the said charge of compressed air.
Engine which works on the Diesel principle or
Diesel cycle.
4. 4
Classification
Number of Stroke - Two Stroke and Four Stroke
Ignition - Compression and Spark
Cylinder Arrangement - Inline and ‘V’
Speed - Low, Medium and High
Classification :
5. 5
Terminology
Looking The Engine From Flywheel End
Operating side – left hand or in V-engine A-side.
Back side – opposite of operating side or in V-engine B-side.
Flywheel end – end where flywheel is
Free end – opposite of flywheel end
Bottom – underside
Top – opposite of the bottom
10. 10
Flywheel :
Components
Bolted to flywheel end of
crankshaft by flange connection
Specific number of bolts are reamed
Smoothens out the speed fluctuations caused by non uniform flow of
power to and from the piston during each stroke
Thin and large diameter disk with
high inertia
12. 12
Piston Ring :
Components
Made of high quality cast iron
Piston Ring set consist:
• Two comp. + One oil scrapper ring in 32LN
• 2+2 combination or
• 3+1 combination i.e. 3
compression rings plus one oil
scrapper ring or
Cylinder tightness is further
improved by inherent spring force
20. 20
Oil Sump
The oil sump, bolted to the bottom of the engine block,
holds the entire lubrication oil quantity,
unless it is a so called dry sump installation.
Cast in one piece.
The material is special quality of grey iron or nodular cast iron
Crankshaft is under slung, i.e. supported by main bearing caps from underneath
Camshaft bearing housings are directly machined in the engine block
Jacket water distribution pipes, lubrication oil pipes and charge air receiver can be incorporated in the engine block
Main bearing caps are usually bolted to the block also with a pair of side bolts, for increased engine block stiffness. The bolts are hydraulically tightened.
The crankshaft converts the up and down movements of the pistons (via the connecting rods) to a rotary motion
Made of forged alloy steel in one piece and heat treated to obtain optimum strength. The heat treatment is tempered, quenched and tempered which gives a uniform hardness through the entire shaft, or the bearing journals have also been surface hardened for maximum wear resistance.
In the non-driving end of the crankshaft there is usually a damper to control the torsional vibrations originating from the combustion pulses. There are basically two different types of dampers. The most common is the oil filled damper with a square section ring inside, which rotates driven by the friction of the very thick oil inside the damper. The other type is built up of many leaf springs. The torsional vibration damper prevents a premature fatigue of the crankshaft.
The piston fits snugly in the cylinder liner, to form a tight “plug” that moves up and down in the cylinder. The tightness is further improved with the piston rings that with their inherent spring force are pressed towards the cylinder wall. The engine oil strongly contributes to secure the tightness. The connecting rod’s upper end is fixed to the piston with the gudgeon pin.
The connecting rods connect the pistons to the crankshaft, enabling the conversion of an up and down movement of the pistons to a rotary motion. The force exerted on the piston top is transferred via the connecting rod to the crankshaft. The connecting rod upper end, usually called small end, is equipped with a bearing bush, while the lower end, called the big end, is split into two pieces, with replaceable half moon bearing shells. There are channels in the connecting rod for transport of lubrication oil from the big end into the gudgeon pin and piston.
The cylinder head forms the cover on top of the cylinder, making the cylinder hermetically tight. In the cylinder head there are inlet and exhaust valves, controlled by the camshaft. These valves make the gas exchange in the cylinder possible.
The camshaft is a shaft with an eccentric portion, a cam, which during its rotation pushes a tappet and pushrod, which in turn pushes on a lever, the rocker arm, pivoted in its mid-section and located in the cylinder head, pushing to open the valves. The valves are thus opened and closed in a certain order, making the four stroke process possible. The closing force for the valves is arranged with springs. The camshaft gets its rotation via gear wheels connected to the crankshaft. Two revolutions of the crankshaft correspond to one revolution of the camshaft.
The piston fits snugly in the cylinder liner, to form a tight “plug” that moves up and down in the cylinder. The tightness is further improved with the piston rings that with their inherent spring force are pressed towards the cylinder wall. The engine oil strongly contributes to secure the tightness. The connecting rod’s upper end is fixed to the piston with the gudgeon pin.
The oil sump holds the entire lubrication oil quantity, unless it is a so called dry sump installation.
Lubricating oil sump, with splash baffles and hydraulic jacks (for lowering and lifting the main bearing caps)
Turbo charger with two horizontal exhaust gas inlet ports and one vertical outlet port.
Water cooled housing.
The charge air cooler(s) cools the compressed and hot air after the turbo charger before the air enters the charge air receiver (air manifold) and the cylinders.