Automobile engineering ppt foe annauniversity syllabus

2. PETROL ENGINE FUEL SUPPLY SYSTEM:
ELECTRONIC CONTROLLED FUEL INJECTION SYSTEM
In Electronic Fuel injection system, fuel supply and timings are controlled by electronic means.
It is developed with the help of solid-state electronic devices such as diodes and transistors.
SCHEMATIC DIAGRAM FUEL INJECTION IN PETROL ENGINE

3. PETROL ENGINE FUEL SUPPLY SYSTEM:
ELECTRONIC CONTROLLED FUEL INJECTION SYSTEM
Four modules of the Electronic Fuel Injection system are:
1.Fuel Delivery System
2. Air Induction System
3. Sensors and air flow control system
4. Electronic Control Unit
I.FUEL DELIVERY SYSTEM
• This System Contains Electrically Driven Fuel Pump (draws fuel from fuel tank
through filter) & forces it into pressure line where Fuel Pressure Regulator is situated.
• Fuel Pressure regulator is connected to the Intake Manifold.
• Pressure Difference between the fuel pressure & manifold pressure is kept constant
by this regulator so that quantity of fuel injected depends on injection open time only.
II.AIR INDUCTION SYSTEM
• Incoming air from atmosphere initially flows through filter and through air flow
sensor.
• Sensor measures the amount of air flow & generates voltage signal which depends on
amount of air flow.

4. PETROL ENGINE FUEL SUPPLY SYSTEM:
ELECTRONIC CONTROLLED FUEL INJECTION SYSTEM
III.SENSORS & AIR FLOW CONTROL SYSTEM:
• Through various sensors, air fuel mixture will be directly injected into the
engine.
• Oxygen Sensor checks the amount of oxygen passes in the
exhaust gas and send this information to electronic control unit.
IV. ELECTRONIC CONTROL UNIT:
• Electronic Control Unit acts as a Central Processing Unit which receives the
signals from various sensors and automatically monitors and regulates the system.

5. PETROL ENGINE FUEL SUPPLY SYSTEM:
ELECTRONIC CONTROLLED FUEL INJECTION SYSTEM
Application:
In modern vehicles, which uses fuel injection for petrol engine operates in the sequence as
shown below. Vehicle which uses direct fuel injection are
MAZDA, AUDI, VOLKSWAGEN, BMW, ALFA

6. DIESEL ENGINE FUEL SUPPLY SYSTEM:
Three methods of Electronic Controlled Diesel Fuel Supply system is:
1. Unit Injector System
2. Rotary Distribution Type
3. Common Rail Direct Injection System
I. UNIT INJECTOR SYSTEM (UIS)
• The Unit Injector System (UIS) combines the
injection nozzle and the high-pressure pump in a
single assembly. One such Unit Injector is fitted in the
head of each engine cylinder.

7. I. UNIT INJECTOR SYSTEM (UIS)
Mainly it consists of four main Phases:
• Filling Phase
• Spill phase
• Injection phase
• Pressure reduction phase.
DIESEL ENGINE FUEL SUPPLY SYSTEM:

8. DIESEL ENGINE FUEL SUPPLY SYSTEM:
II. ROTARY DISTRIBUTION TYPE INJECTORS
• Rotary Distribution pumps have only one fuel-metering plunger.
• A spinning rotor makes a hydraulic connection with the different ports on the distributor
head, somewhat similar to the way a distributor works on a gasoline engine.
• Benefits of a rotary-style pump with only one plunger are all the shots of fuel are
exactly the same, and it makes for a smaller overall package. Also, distributor-style
pumps have less moving parts compared to inline pumps.

9. DIESEL ENGINE FUEL SUPPLY SYSTEM:
III. COMMON RAIL DIRECT INJECTION SYSTEM
Common Rail Injection System has benefits of High Injection Pressure and finer atomizing
of fuels and reduction in overall exhaust emissions.

10. ELECTRONIC IGNITION SYSTEM:
This Electronic Ignition Control System controls fuel combustion by providing a spark to
ignite the compressed air/fuel mixture in each cylinder at the correct time. This ignition
control system has several advantages over a mechanical distributor ignition system.
Battery Ignition system or Coil Ignition system:

11. When the contact breaker points are closed:
1.The current flows from the battery to the contact breaker points through
the switch and primary winding and then returns to battery through the earth.
2. This current builds up a magnetic field in the primary
winding of the ignition coil.
3When the primary current is at the highest peak, the contact breaker points
will be opened by the cam.
When tile contact breaker points are opened: Second stroke:
1. The magnetic field sets up in the primary winding is suddenly collapsed.
2.A high voltage (15000 volts) is generated in the secondary winding of the
ignition coil.
3. This high voltage is directed to the rotor of the distributor.
4.The rotor directs this high voltage to the individual spark plugs in the
sequence of the firing order of the engine.
5.This high voltage tries to cross the spark plug gap (0.45 to
0.6mm) and the spark is produced. This spark ignites the fuel- air mixture.

12. TURBO CHARGERS:
An Engine may not produce same power output when it is operated at different location
and altitudes. Super charging & turbo charging is used to overcome this effect.
Super charging is the process of supplying the fuel (or air-fuel mixture) above the
atmospheric pressure by boosting the pressure.
When the supercharger is driven by gas turbine which derives gas from engine exhaust, it
is called TURBO CHARGER.

13. • The exhaust from the cylinders passes through the turbine blades, causing the turbine to
spin. The more exhaust that goes through the blades, the faster they spin.
• On the other end of the shaft that the turbine is attached to, the compressor pumps air
into the cylinders. The compressor is a type of centrifugal pump -- it draws air in at the
center of its blades and flings it outward as it spins.
• In order to handle speeds of up to 150,000 rpm, the turbine shaft has to be supported
very carefully. Most bearings would explode at speeds like this, so most turbochargers use
a fluid bearing.
• This type of bearing supports the shaft on a thin layer of oil that is constantly pumped
around the shaft. This serves two purposes: It cools the shaft and some of the other
turbocharger parts, and it allows the shaft to spin without much friction.
• The turbocharger is bolted to the exhaust manifold of the engine. The exhaust from the
cylinders spins the turbine, which works like a gas turbine engine.
• The turbine is connected by a shaft to the compressor, which is located between the air
filter and the intake manifold. The compressor pressurizes the air going into the pistons.
TURBO CHARGERS:

14. ENGINE EMISSION CONTROL: (Emission Norms)
Each Country has its own specification to allow the engine emission gases and it specifies
the quantity of gases like NOx, CO, HC etc. (potential gases to pollute atmosphere)
permitted in the atmosphere per kilometer of vehicle travel. In India, the latest
specification is from
Bharat Stage IV (Some vehicles pasted Sticker Bharat Stage IV or BS IV)
Bharat Stage III
Bharat Stage II

15. ENGINE EMISSION CONTROL: (Emission Norms)
Similarly for Diesel vehicles also, emission norms are as follows:

16. ENGINE EMISSION CONTROL: (3 WAY CATALYTIC CONVERTOR)
• The Catalytic Convertor Converts the
toxic gases like HC, CO, NOx into
harmless gases.
• It contains ceramic or metallic base with
active coating incorporating alumina and
other oxides with combination of
precious metals like platinum, palladium
and rhodium.
• Inside the passage way of catalytic
convertor is a honey comb set passage
way or ceramic bead coated with catalyst.
It makes chemical reaction without being
part of the reaction.
• Convertors may TWO WAY or THREE
WAY Catalytic convertor.
• Two Way convertors are Oxidation
catalytic convertor.
• Three way Convertor are Oxidation as
well as Reduction Catalytic Convertor.

17. ENGINE EMISSION CONTROL: (3 WAY CATALYTIC CONVERTOR)
• In 3 Way Convertors, 3 refers to emission
control of CO, HC and Volatile Organic
Compounds (VOC).
• It uses 2 types of Catalyst >> Oxidation Catalyst
& Reduction Catalyst both structure coated with a
catalyst such as Platinum, Rhodium & Palladium.
• REDUCTION CATALYST is the first stage of
catalytic convertor which uses platinum &
rhodium to help reduce NOx emissions.
Reaction:
2NO N2 + O2
2NO2 N2 + 2O2
• OXIDATION CATALYTST is the second stage of the catalytic convertor which reduces
the unburned hydrocarbons and carbon monoxide by burning (oxidizing) them over a
platinum and palladium catalyst. This aids the reaction of the CO & HC with remaining
Oxygen in exhaust gas.
Reaction:
2CO +O2 2CO2
VEHICLE WITH CATALYTIC CONVERTOR MUST USE UNLEADED PETROL AS LEAD IN
PETROL RESTS THE CATALYST & MAKE INEFFECTIVE.
IN DIESEL ENGINE CATALYTIC CONVERTOR REDUCES HC & CO (OXIDATION) AND
CANNOT REDUCE NOx EMISSIONS.