Page 296 - Mechanic Diesel - TT

MECHANIC DIESEL - CITS

Compression test

A compression test measure’s a cylinder ability to hold pressure as the piston move’s up and down. The pressure
at the end of the operation is about 35 bar in petrol engine and about above 95 bar and above (HCV) in diesel
engine.

A good rule of thumb says that each cylinder in mechanically compression should have approximately 130 psi
(8.96 bar) and higher.

Visually inspection
The engine should be inspected visually for any signs of damages or wear. This includes looking for cracks, leaks,
excessive corrosion and any other things.

Visual inspection is non-destructive testing method for quality control. In its original form, visual inspection is used
to observed the surface of an engine any other physical activates
Performance testing
Performance testing basically its including some technical specification about engine like friction power, indicative
power, brake power, specific fuel consumption, air fuel ratio, thermal efficiency, mechanical efficiency, volumetric
efficiency etc.

Here for measuring power and torque use dynamometer.
Dynamometer are types is
1 Prony brake dynamometer
2 Rope dynamometer

3 Hydraulic dynamometer
4 Belt transmission dynamometer
5 Epicyclic dynamometer
6 Torsion dynamometer

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CITS : Automotive - Mechanic Diesel - Lesson 87