Page 312 - Mechanic Diesel - TT

MECHANIC DIESEL - CITS

6 Approximately 20,000 km. I. Overhaul the pressure reducer - vaporizer after running. Pressure reducer Clean
all parts first with gasoline and then with pressurized dry air. Replace diaphragm, rubber pad if damaged.
Consider the position and height of the rocker when fitting the rubber pad and rocker. Then check the air
tightness of the seals and rockers as well as the functioning of the diaphragm.
Comparison Between Gasoline, Diesel, LPG and CNG
Characteristics of Gasoline

Following are the main properties of gasoline-
1 Volatility - Gasoline is highly volatile. It evaporates at 90°C with a vapor pressure of 0.5 to 1.0 kg/cm². Due to
this quality, the engine becomes very easy to start and run. Acceleration also happens quickly.

2 Purity - It should not contain impurities like water, grease, dust particles etc.
3 Sulfur Content - Crude oil contains sulfur content. even after refining it Some amount of sulfur remains in
gasoline, which causes rust in various parts of the engine. The amount of sulfur in gasoline should be up to
0.1%.
4 Gum Content - The amount of gum in gasoline should also be controlled. Excessive amount of glue causes
valves to stick, piston rings to stick, carburetor jets to jam, intake manifold to clog.

5 Anti-lock Quality - If the octane number of gasoline is high, there is no knocking in the engine.
6 Calorific Value - Calorific value of gasoline should be high. it usually It is 24000 CHU/Kg.
Economic Profit - Gasoline should be profitable from economic point of view also. Due to this, the car should
run more kilometers in one liter.
Properties of Diesel Fuel
Following are the main properties of diesel fuel-
1 Grade - Grade Number ID Diesel Engine Fuel is high volatile distilled fuel. Grade No. 2D diesel engine fuel is
a low distilled fuel.
2 Gravity - It displays specific gravity.
3 Pour Point - This is the minimum temperature at which fuel will flow under a certain test condition.
4 Volatility - This is the measure of the volatile state of the fuel.

5 Flash Point - This is the temperature at which the fuel gives enough vapor to burn.
6 Distillation Recovery - This is the volume of fuel that is obtained by heating it till boiling point and then
condensing the vapor.

7 Cetane Rating - This shows the ignition quality of the fuel and how fast it burns.
8 Viscosity - This is the measure of the flow resistance of the fuel.
9 Water and Sediment - The amount of water mixed in the fuel causes rust in the injection system. Filters get
clogged with sediments.

10 Ash - It is a non-flammable substance in fuel.
Liquid Petroleum Gas (LPG)
There are two types of liquid petroleum gas used in automobile engines – propane and butane. A mixture of both
is also used. They are used in buses, trucks, railways and factories. Propane boils at 44°F. Therefore, it can be
used in any climate where the temperature is not lower than this. Butane is liquid below 32°F. Therefore, it cannot
be used where the temperature is lower than this. If it remains liquid, it will vaporize and not reach the fuel system.

Propane and butane are obtained from oil and gas wells. They are obtained by the petroleum industry from
natural gas plants, cycling condensing plants and refinery processes. These are condensed and stored as liquid
in sealed pressure tanks. They are extremely flying at low pressure. A special fuel system is required to bring the
fuel from the fuel tank to the engine cylinder.
CNG means Compressed Natural Gas, like Crude Oil is obtained from the ground and after purifying that mineral
oil, various substances like petrol, diesel, kerosene oil are extracted from it, similarly this gas is also obtained

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CITS : Automotive - Mechanic Diesel - Lesson 88 - 93 CITS : Automotive - Mechanic Diesel - Lesson 88 - 93