Page 328 - Mechanic Diesel - TT

MECHANIC DIESEL - CITS

It is also called nozzle, atomizer or fuel valve. A cap nut is fitted at the top point of the injector and a nozzle is
fitted at the bottom point. Parts like spindle, pressure adjusting screw, nozzle, nozzle spring etc. are fitted inside
the injector. Injecting a flowing object into a limited space is called injection, that is, in diesel engines, introducing
diesel fuel in the form of a spray of small particles into the hot air of the combustion chamber is called injection.
This injection is done by injector. It is also called fuel spray valve or atomizer. Injection is done through the
injector at a pressure of 1500 to 2000 per square inch (PSI), because at the end of the compression stroke the
air pressure in the combustion chamber is approximately 550 pounds per square inch and the temperature of the
compressed air at that time is 500°C. It remains at 700°C. As soon as this injection takes place, the diesel gets
burnt when it comes in contact with hot air, which provides power.

Closed and open loop system, cold start system, Air
flow measurement, Variable intake manifold system, EFI

wiring system, Electronic control unit, pre heaters for inlet

manifold, Data link connector, On board diagnostic system

Objectives: At the end of this lesson you shall be able to
• explain about closed and open loop system, cold start system, air flow measurement & variable intake
manifold system
• explain EFI wiring system, electronic control unit, pre heaters for inlet manifold
• use data link connector & on board diagnostic system.

Closed and open loop system, cold start system, Air flow measurement, Variable intake manifold system.
Closed and Open Loop Systems
Closed-loop system: Also known as feedback control system, it uses feedback from the output to control the
input. It adjusts itself based on the difference between the actual output and the desired output.
Open-loop system: Also known as feedforward control system, it doesn’t use feedback to adjust the input. It
relies solely on the input command and doesn’t consider the actual output.
Cold start system: Cold start systems provide additional fuel during starting. conditions, according to engine
temperature.
Air measurement: The vane - type airflow sensor measures the quantity of air flowing into the engine by deflecting
a spring - loaded vane across a potentiometer. This provides a signal voltage to the ECU.
Air flow monitoring: Depending on the application, different kinds of sensors measure different properties of the
air entering the engine, including its temperature, volume, density and mass.
Variable intake manifold system: Variable intake manifold systems vary the effective manifold pipe length, to
extend the torque curve over a wider RPM range.
EFI (Electronic Fuel Injection) wiring system, Electronic control unit, Pre heater for inlet manifold.
EFI (Electronic Fuel Injection)

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CITS : Automotive - Mechanic Diesel - Lesson 98 - 103 CITS : Automotive - Mechanic Diesel - Lesson 98 - 103