Page 300 - Mechanic Diesel - TT

MECHANIC DIESEL - CITS

Procedure for performing engine vacuum tests

Perform a vacuum gauge test to determine engine condition and performance.
Note
Accurately diagnosing problem with a vacuum gauge can be difficult. Steady and compare reading
to diagnostic charts.
Connect the vacuum gauge to an intake manifold vacuum source. Connect a vacuum hose to an
accessible intake manifold vacuum connector and extent it up to the vacuum gauge.
Connect the exhaust ventilation equipment.

Caution
Be use to sure approved exhaust ventilation equipment when operating a vehicle in an enclosed area.
Start the engine and allow it to reach normal operating temperature.

Measurement of ihp, indicative mean effective pressure, bhp, mechanical efficiency, fuel consumption
Indicated horse power (IHP) - The power developed in an engine cylinder, is called the indicated horsepower.
The formula is as follows

Pm LAN
IHP = x K
4500
Here,
2πNT
pm = mean effective pressure (in kg/cm)
BHP =
4500
L = stroke length (in meters)
A = Area of the piston (in cm)
N = Number of strokes in one minute BHP
IHP −
FHP =
K = number of cylinders.

BHP
Mechanical efficiency = x100
287
IHP
CITS : Automotive - Mechanic Diesel - Lesson 87 CITS : Automotive - Mechanic Diesel - Lesson 87

Pm = W/Vs

Area of the diagram
Area of height =
Length of the diagram