A) Lubrication System in I.C. Engines

Introduction The lubrication system in an Internal Combustion (I.C.) engine reduces friction between moving parts, prevents wear and tear, removes heat, and ensures smooth operation of the engine.

Functions of Lubrication System

 Reduces friction – Minimizes wear and tear of engine components.
 Prevents overheating – Carries away excess heat from moving parts.
 Cleans engine parts – Removes dirt and metal particles.
 Prevents corrosion – Forms a protective layer on metal surfaces.
 Seals the piston rings – Reduces leakage of combustion gases.

Types of Lubrication Systems

1. Petroil System (Mist Lubrication System)

• Used in two-stroke engines like motorcycles, scooters, and small agricultural machines.
• Lubricating oil is mixed with petrol (usually in a 2-5% ratio).
• Oil burns along with fuel and lubricates engine parts.

Advantages:
Simple and cheap.
No separate oil pump needed.

Disadvantages:
High oil consumption.
Causes carbon deposits.

2. Splash Lubrication System

• Used in small engines (lawnmowers, old tractors).
• Oil is stored in the crankcase, and a scoop or dipper splashes oil onto engine parts.

Advantages:
Simple and low maintenance.
No oil pump required.

Disadvantages:
Not suitable for high-speed engines.
Uneven lubrication.

3. Pressure Lubrication System

• Used in modern tractors, cars, and diesel engines.
• Oil pump forces oil through pipes to lubricate engine parts.

Advantages:
Uniform lubrication.
Suitable for high-speed engines.

Disadvantages:
Requires oil pump and filter maintenance.
Costlier than splash system.

4. Dry Sump Lubrication System

• Used in racing cars, aircraft, and high-performance engines.
• Oil is stored in a separate tank, and a pump circulates oil to engine parts.

Advantages:
Ensures continuous oil supply even on steep slopes.
Prevents oil starvation in extreme conditions.

Disadvantages:
Expensive and complex.
Requires extra space for oil tank.

Components of Lubrication System

Oil Pump – Forces oil to different parts of the engine.
Oil Filter – Removes dirt and metal particles from the oil.
Oil Cooler – Reduces oil temperature to maintain efficiency.
Oil Sump – Stores lubricating oil at the bottom of the engine.
Pressure Relief Valve – Controls oil pressure.

Comparison of Lubrication Systems

Maintenance Tips for Lubrication System

Check oil level regularly and top up if needed.
Change engine oil and filter at recommended intervals.
Use the right grade of oil as per manufacturer specifications.
Inspect oil pump and pressure gauge for proper functioning.

B) Fuel Supply System in I.C. Engines

Introduction The fuel supply system in an Internal Combustion (I.C.) engine ensures the proper delivery of fuel to the engine for efficient combustion. The type of fuel system varies depending on whether the engine is a petrol (SI) engine or a diesel (CI) engine.

Types of Fuel Supply Systems

1. Fuel Supply System in Petrol Engines (Spark Ignition – SI Engine)

• Uses petrol as fuel.
• Works on the principle of carburetion or fuel injection.
• Fuel-air mixture is prepared before entering the combustion chamber.

Main Components:

1. Fuel Tank – Stores petrol.
2. Fuel Pump – Delivers fuel from the tank to the carburetor.
3. Carburetor – Mixes fuel with air in the correct ratio.
4. Air Filter – Removes dust from incoming air.
5. Fuel Injector (in modern engines) – Sprays fuel directly into the intake manifold.

Types of Petrol Fuel Supply Systems

Gravity Feed System – Used in motorcycles where the fuel tank is above the carburetor.
Pressure Feed System – Used in aircraft engines, where fuel is supplied under pressure.
Pump Feed System – Uses a mechanical or electric fuel pump to deliver fuel.

2. Fuel Supply System in Diesel Engines (Compression Ignition – CI Engine)

• Uses diesel as fuel.
• Fuel is injected directly into the combustion chamber.
• Requires a high-pressure fuel injection system for proper atomization.

 Main Components:

1. Fuel Tank – Stores diesel fuel.
2. Fuel Filter – Removes impurities and water from diesel.
3. Fuel Pump – Pressurizes the fuel before sending it to injectors.
4. Injector – Sprays atomized fuel into the combustion chamber.
5. Fuel Return Line – Returns excess fuel back to the tank.

Types of Diesel Fuel Supply Systems

Air Injection System – Uses compressed air to inject fuel (obsolete).
Solid Injection System – Fuel is injected under high pressure (modern engines).

• Common Rail Direct Injection (CRDI) – Used in modern diesel engines for better efficiency.
• Unit Injection System – Each cylinder has a separate fuel injection pump.

Comparison of Petrol vs Diesel Fuel Supply Systems

Maintenance Tips for Fuel Supply System

Use clean fuel and avoid contamination.
Replace fuel filters regularly.
Check fuel pump pressure for efficiency.
Ensure injectors are clean to prevent clogging.
Drain water separators in diesel engines to avoid fuel contamination.

C) Hydraulic Control System of a Tractor 🚜

Introduction The hydraulic control system of a tractor is used to lift, lower, and adjust implements like plows, cultivators, and harrows. It helps in efficient farming operations by reducing manual effort and improving precision.

Main Components of the Hydraulic System

1. Hydraulic Pump – Generates hydraulic pressure to operate the system.
   2. Hydraulic Fluid – Transfers power through the system.
   3. Hydraulic Cylinder – Converts fluid pressure into mechanical force to lift/lower implements.
   4. Control Valve – Regulates the flow of hydraulic fluid.
   5. Hydraulic Lever – Used by the operator to control the hydraulic system.
   6. Three-Point Linkage – Connects tractor implements for smooth operation.

Types of Hydraulic Control Systems in Tractors

1. Draft Control Automatically adjusts the depth of implements like plows based on soil resistance. Helps maintain uniform plowing depth.
2. Position Control Allows the operator to set and maintain the exact position of an implement. Used for operations like harrowing and leveling.
3. Mixed Control Combines features of both draft control and position control. Provides both depth and height adjustment for implements.

Working of a Tractor Hydraulic System

The hydraulic pump draws oil from the reservoir and pressurizes it.
The control valve directs the pressurized oil to the hydraulic cylinder.
The cylinder moves the piston, which lifts or lowers the attached implement.
The three-point linkage moves accordingly, adjusting the implement’s position.
When the lever is released, the system locks the position until further adjustment.

Advantages of a Hydraulic System in Tractors

Reduces manual labor and increases efficiency.
Provides precision control over farm implements.
Enhances safety in lifting and lowering heavy loads.
Improves tractor performance with smooth operation.

Maintenance Tips

Check hydraulic fluid levels regularly.
Replace hydraulic filters periodically.
Inspect hoses and connections for leaks.
Use recommended hydraulic oil for better performance.