The document summarizes the key components and operation of a diesel fuel injection system. It discusses the fuel tank, fuel filter, fuel lines, fuel pumps, injectors and nozzles, ECU and sensors. The fuel is stored in the tank and delivered to the injectors by low-pressure and high-pressure fuel pumps. The ECU controls the injectors and precisely times the injection of fuel into the combustion chamber based on sensor inputs like engine speed. This allows for proper atomization and mixing of fuel for clean and efficient combustion in the diesel engine.

1. FUEL DELIVERY SYSTEM
(DIESEL)
ASSIGNMENT- PTMS
Submitted by –INTAKHAB KHAN &VISHWAM PANCHAL
Under the guidance of – Dr. SANJAY A PATIL

2. Table of contents
1. Introduction
2. About diesel fuel
3. Fuel injection system working
4. Components of fuel injection system
i. Fuel tank
ii. Fuel filter
iii. Fuel lines
iv. Fuel pumps
v. Injectors and nozzles
vi. ECU & sensors
References
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3. 1. INTRODUCTION
• In diesel fuel injection system the fuel(diesel) is to being atomized and injected
a precise amount of fuel into the chamber when the air is compressed at proper
time.
• The fuel stored in the tank is supplied to the injector by low pressure and high
pressure pumps and the ECU controls the time and amount of fuel to be
injected into the cylinder for perfect combustion of fuel.
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• By perfect combustion it means all the fuel is utilized to produce the
power, low emission and optimum fuel economy.
• The ECU controls the amount of fuel by lifting the solenoid valve for
certain amount of time and for certain amount of nozzle opening.

4. 2. Some important points about diesel fuel
- It is a linear saturated hydrocarbon obtained by distillation of crude oil.
- High energy content hence have better mileage than gasoline other reason for better mileage is that diesel can burn even
when the air fuel mixture is too lean since the combustion starts at multiple points.
- Less volatile due to higher flash point hence do not use spark plug
- Less auto ignition temperature hence uses compressed air temperature for ignition
- More viscous hence injected at higher pressure for atomization(Around 2000 bar) and also swirl motion of air is
generated for perfect atomization and mixing
- Dense as compared to petrol hence it needs more powerful fuel pumps for raising the pressure up to 2000 bar.
- To raise the temperature to auto ignition temperature it’s compression ratio is higher (14:1-25:1) as compared to petrol
engine. And due to this it have better thermal efficiency. Also it takes in lot of air due to larger size of cylinder
producing better power and torque.
- The ignition starts at the multiple points inside the cylinder at which the temperature is above auto ignition temperature
and perfect amount of fuel and air is present.
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3. Fuel injection system working

6. • A- Rail Pressure sensor, B-High pressure rail , C-pressure control valve, D-ECU,
E-Piezo injector, F- Fuel return line G- Pressure holding valve H-High pressure
pump, I-Electric Pre supply pump, J-Pre filter, K-Fuel filter
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7. Types of fuel injection
1. Air injection type
2. Solid injection type
• Individual pump and injector for each cylinder
• Unit injector type
• Distributor type
• Common rail System
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8. 4. Components of fuel injection system and their types
a) FUEL TANK
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BMW x3 PLASTIC FUEL TANK
Toyota Hilux sheet metal Fuel tank
They store the fuel and consists of low pressure transfer pump inside it. They are made up of either sheet metal or
plastic as shown in the figure and consists of fuel level sensor.
It also contains fuel vapour vent tube connected to canister to store the vaporized fuel, return line tube connected with
the tank. It also consists of drain plug at the bottom. Fuel level sensor helps to indicate the fuel indicator in dashboard.

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Drain plug
Fuel pump
Fuel level
sensor
Vapor vent tube

10. 4. Components of fuel injection system and their types
b) Fuel filter
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The fuel from the fuel tank needs to be filtered to remove foreign particle which may damage fuel
pump, injector and engine cylinder, lead to wear or moving parts, blockage in fuel flow hose and
corrosion. Hence the diesel fuel is filtered more than once before injecting into cylinder.
It consists of two filters primary and secondary filter.

11. 4. Components of fuel injection system and their types
c) Fuel lines
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They are the hoses used to transfer the fuel from fuel tank to the engine cylinder. They are of 3
types in case of Diesel engines heavyweight lines for the high pressures found between the
injection pump and the injectors, medium weight lines for the light or medium fuel pressures
found between the fuel tank and injection pump, and lightweight lines where there is little or no
pressure.

12. 4. Components of fuel injection system and their types
d) Fuel pumps
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An electric pump has a similar diaphragm-and-valve arrangement, but instead of the camshaft, a
solenoid (an electromagnetic switch ) provides the pull on the diaphragm.
The solenoid attracts an iron rod that pulls the diaphragm down, drawing petrol into the chamber.
At the end of its travel the iron rod forces apart a set of contacts, breaking the current to the
electromagnet and relaxing the pull on the diaphragm.
When the diaphragm return spring raises the diaphragm, it also pulls the rod away from the
contacts; they then close so that the solenoid pulls the rod and diaphragm down again.

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15. 4. Components of fuel injection system and their types
e) Fuel injectors and nozzels
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The injectors used now a days are electrically actuated solenoid valve after receiving the signal from ECU for certain
amount of time as per the amount of fuel decided to be injected.
The injectors through which the fuel is sprayed are screwed, nozzle-first, into the cylinder head and are placed in such
a way that the fuel is sprayed evenly all over the chamber.
The injectors are one of two types, depending on the injection system. The first system uses continuous injection
where the fuel is squirted into the inlet port all the time the engine is running. The injector simply acts as a spray
nozzle to break up the fuel into a fine spray - it doesn't actually control the fuel flow. The amount of fuel sprayed is
increased or decreased by a mechanical or electrical control unit - in other words, it is just like turning a tap on and
off.
The other popular system is timed injection (pulsed injection) where the fuel is delivered in bursts to coincide with
the induction stroke of the cylinder. As with continuous injection, timed injection can also be controlled either
mechanically or electronically.

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Multiple injection-pilot injection

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4. Components of fuel injection system and their types
e) ECU and Sensors

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Sensors used :
1. Mass air flow sensor
2. Throttle position sensor
3. Engine temperature sensor
4. Cam shaft position sensor
5. Engine speed sensor
6. Crankshaft position sensor
7. Knock sensor
8. Manifold pressure sensor
9. Air inlet temperature sensor
10. Oxygen sensor

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Fuel map-for ECU to control amount of fuel to be injected

21. References
1. https://dieselnet.com/tech/diesel_fi.php
2. https://www.ezoil.com/resources-diesel-engines-diesel-fuel-system-basics
3. https://www.gcoeara.ac.in/learning_material/auto/Unit%205-AEE.pdf
4. https://www.heinzmann.com/en/products/efi-controllers
5. https://www.youtube.com/watch?v=jWW0BsIQ2mQ
6. https://www.youtube.com/watch?v=5VLNOFh0a3k
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22. THANK YOU
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Submitted by
INTAKHAB KHAN
&
VISWAM PANCHAL