6. Fueling System
A Proper fueling system is required for proper functionality of a Automobile. If a Automobile has malfunctioning Fueling System, the automobile may use more fuel or less fuel efficient and may produce harmful effects to the whole Automobile. Thus maintaining a fueling system is important in the life cycle of the Automobile.
The fueling system used for Petrol(Gasoline) and Diesel are completely different as both engines work on different cycles and principle. The Gasoline engine works on Otto cycle while the Diesel engine works on Diesel Cycle.
6.1 Petrol(Gasoline) Fueling System
The Petrol engine utilizes Otto Cycle as said above. The Otto cycle ignites the fuel instead of burning the fuel. The ignition causes movement of the piston and produces power. This is completely different from the Diesel Cycle. In the Otto Cycle , Fuel is mixed with air and then sent into the combustion chamber. Thus making the fuel more ignitable.
6.2 Diesel Fueling System
This system also utilises a cycle similar to Otto Cycle. It is called the Diesel Cycle. In Diesel Cycle fuel is burned by compression instead of ignition. The fuel is injected into the Combustion chamber in high pressure, about 60,000 times of Atmospheric Pressure. As the fuel is injected while the piston is moving up, the fuel gets high compression. Thus making the fuel burn and push back the Piston.
6.2.1 Injectors
The injectors in a Diesel engine is very much important part than any other part of the Diesel Engine, thus anything happening to the injectors will directly affect the engine. The injectors are usually controlled by Electronic Control Module(ECM) or Electronic Control Unit(ECU). The injector is initially supplied with a battery voltage via a relay, in which the earth circuit is controlled by ECM/ECU. When the circuit is completed by the ECU a solenoid operates, the injector valve opens, fuel is then able to be sprayed into the inlet manifold. The valve moves roughly 1.5-10 milliseconds. This is known an injector duration or opening time. The ECU will make amendments to the duration depending on engine temperature, loading air temperature and battery voltage
6.2.1.1 Injector Types
6.2.1.2 Common Rail System
6.2.1.3 Jerk Pump System
#Cooling System
6.3 Pressurized Cooling System
{pagebreak}#Lubrication System
6.4 Functions of Lubrication System
The main functions of the Lubrication system are,
- Cooling Down Engine Parts
- Cleaning engine from broken pieces from friction between cylinder and piston.
- Keeping the piston rings and cylinder wall enclosed and keeping it air tight.
- Reducing Vibration between bearings and engine parts
6.5 Types of Lubrication System
There are several types of Lubrication systems. Out of them, these are the major 3 categories.
- Petroil Lubrication System
- Splash Lubrication System
- Pressure Feed Lubrication System
6.5.1 Petroil Lubrication System
Petroil Lubrication system is used in 2 stroke petrol engines. In these oil pump and filter is not used. When its fuelled, 3-6 % of 2T oil is added to the fuel. When engine operates, the fuel air mixture is taken in and the oil mixed in the fuel lubricates the engine parts such as Bearings, Piston rings, Cylinder walls, Piston Pin/ Gudgeon Pin.
6.5.2 Splash Lubrication System
This is used mainly in small 4 stroke engines. On the big end of connecting rod, brearing cap, a rod dipper is attached. Due to the rotational movement, they splash the oil into the engine parts from the oil sunk.
6.5.3 Pressure Feed Lubrication System
This is used mainly in large 4 stroke engines. In this engines, a oil pump and a oil filter is attached. The oil pump forces the oil into the oil filter and after filtering of the oil, the oil travels through the galleries designated to be reached by the oil. Furthermore, it enters sprayers located below pistons. As a result of this lubrication mechanism, a Thin layer forms in between the Cylinder and the piston head, thus filling the space in between them.
Types of Oil Pumps used in this system are
- Gear Pump
- Rotor Pump
- Cresent Pump
6.6 Features / Properties of Lubricant
- High Viscous Point - determines the flowing rate of oil through surfaces and oil films.
- removing waste materials or rust resistance
- viscosity index - the change of viscosity according the heat change in the engine. it is ranged from the 0 to 100, the higher means lesser co-efficeint of change.
- SAE 30W
- SAE 5W - 30 (High Cost, multi-viscosity oil)