Tractor Engine

COMPONENTS OF WATER COOLING SYSTEM:

RADIATOR:

Ø  Radiator contains a vertical or horizontal finned tubing section

Ø  It is designed to hold an abundant amount of water and ethylene glycol, or antifreeze

Ø  The outside air that passes through the radiator grille helps to cool the liquid

Ø  The radiator reduces the temperature of the coolant, which has absorbed the heat from the engine, keeping it within a normal operating temperature.

Ø  Overheating an engine can cause permanent damage. A leaking radiator will cause engine to run at a higher than normal temperature and may cost you huge money in engine repair costs.

Ø  A radiator should always be completely filled with water, antifreeze/coolant or a mixture 

Ø  The radiator can also accumulate internal residues. The cooling efficiency can be dramatically reduced as a result. If you find your vehicle is running at higher than normal temperatures, it may be time to install a new replacement or high performance radiator.

Water Pump:

Ø  The water pump is a simple centrifugal pump driven by a belt connected to the crankshaft of the engine. The pump circulates fluid whenever the engine is running.

Ø  If your water pump isn't operating, the engine coolant just sits in the block and heads. It doesn’t circulate or flow to the radiator to displace its heat. No coolant heat displacement from the radiator means your vehicle will quickly overheat.

Ø  This will lead to costly damage even irreversible damage such as blown engine

Thermostat:

Ø  The thermostat in a vehicle regulates the flow of coolant throughout the system.

Ø  It controls the amount of coolant moving through the cooling system to help keep the vehicle’s engine from overheating

It controls the flow in such a way that the operating temperature is kept within a narrow margin. Your vehicle’s engine operates at peak efficiency within this narrow band of temperature regulation

Water Cooling System:

Advantages

Ø  quieter

Ø  accurate temperature control

Ø  warm water available for heater

Disadvantages

Ø  Need for radiator

Ø  Water pump

Ø  Coolant

Ø  Water jacket around cylinders

Ø  More weight

LUBRICATION SYSTEM:

All moving parts in the engine require lubrication i.e the application of oil to the moving parts to reduce the friction between them

Objective and Functions:

Ø  Reduces friction and wear by introducing a film of oil

                or grease between sliding surfaces

Ø  Cools surface of the piston

Ø  Saves power that may be lost in friction

Ø  Lengthen the life of the piston

Ø  Minimize repair bills

Ø  Absorbs heat

COMPONENTS & FUNCTIONS OF LUB. SYSTEM:

Oil Sump

                The sump is at the base or bottom of an engine. It can be used as a storage container.

Oil pump
Oil is drawn from the sump by an oil pump. It is driven by camshaft. On the suction side of pump a Strainer (sieve) is arranged to check impurities

Oil filters
The oil filter helps to clean the oil by removing the impurities. If the filter clogs, a valve opens and directs unfiltered oil to the engine. Most oil-filters on diesel engines are larger than those on similar gasoline engines.

Oil Galleries:

                These are the small passages in the cylinder block that direct oil to the moving parts.

Oil Level indicator (Dip stick)
Oil level indicators is a graduated rod used to check when there are safe oil levels in an engine

 GRADES OF ENGINE OILS:

 The society of Automotive Engineers grades oils according to their viscosity e.g. SAE-20, SAE-30, SAE-40, SAE-50, SAE-60. Some times like SAE-30 W etc.

Ø  Usually less viscous oils quickly flow when engine is started cold verses dry running until lubricant either warms up sufficiently

Ø  Less dry running means much less engine wear

Ø  FUEL SYSTEM:

Ø  Fuel tank: It hold fuel

Ø  Carburetor: Premixes air and fuel mixture and supply it to the injectors

Ø  Fuel Supply Pump: Supply the fuel to the system from the tank

Ø  Sedimenter: It filter out water from the diesel

Ø  Fuel Filter: To filter fuel and remove minor particles from the fuel. Fuel injectors have tiny openings which clog easily so filtering the fuel is the only way to prevent this. 

Ø  Injection Pump: To deliver highly pressurized fuel to the injectors

Ø  Injection pipes: Connects injection pump with injectors

Ø  Injectors: One for each cylinder to spray fuel into the combustion chamber

Ø  Return lines/ Overflow pipes: To return excess fuel from injection pump and injectors to the tank

Ø  Governors: To control engine speed

Ø  Control Lever: Provide connection between governor and drivers accelerator

IGNITION SYSTEM:

                An ignition system is a system for igniting a fuel-air mixture. Ignition systems are well known in the field of internal combustion engines such as those used in petrol (gasoline) engines used to power the majority of motor vehicles.

Types of Ignition System:

Conventional Ignition system

Battery Ignition (Chemical eng. is converted to electrical eng.)

Magneto Ignition (Mech. eng. is converted to electrical eng.)

Electronic system

Mechanically timed ignition

Electronic Ignition

Digital Electronic Ignition

GOVERNING SYSTEM/ ENGINE CONTROL UNIT:

                An engine control unit is a type of electronic control unit that determines the amount of fuel, ignition timing and other parameters an internal combustion engine needs to keep running. 

Control of fuel mixture

                For an engine with fuel injection, an engine control unit will determine the quantity of fuel to inject

                If the engine has not warmed up, more fuel will be injected (causing the engine to run slightly 'rich' until the engine warms up).

Control of ignition timing

                A spark ignition engine requires a spark to initiate combustion in the combustion chamber. An ECU can adjust the exact timing of the spark (called ignition timing) to provide better power and economy.

Control of variable valve timing

DIFF. B/W PETROL AND DIESEL ENGINES:

Ø  Both are internal combustion IC engines. Petrol and Diesel oil are two separate fractions of crude oil.

Ø  Petrol is lighter, more volatile, and contains hydrocarbons with around 8 carbon atoms per molecule.

Ø  Diesel oil is heavier, less volatile, but with greater lubricity, and contains hydrocarbons with around 10 carbon atoms per molecule.

1.            Petrol engines use spark plugs (Spark Ignition) to ignite the fuel which is a mixture of air and petrol. A diesel engine uses a higher compression ratio (compression Ignition) when it compresses the incoming air, which creates a temperature inside the cylinder which is high enough to ignite the fuel when it is injected into the compressed air. In a diesel engine the Air is compressed to 21 times its normal volume (Approx) and then Fuel is injected into the Cylinder head/ or piston. Due to the high compression the temperature rises and as Fuel is injected it ignites. The Thermal efficiency of a Diesel engine is more as initially the gas was compressed to a higher level and hence the pressure generated on piston is more. Due to the high pressure generated in a Diesel engine the cylinder head , Block, connecting rod, crank Shaft bearing, pistons etc have to be built stronger to withstand higher stress and loads.

2.             Diesel engines consume around 30% less fuel than petrol engines and this results in much lesser carbon dioxide emissions. The diesel engines produce virtually no carbon monoxide and are much safer than petrol engines.

3. A diesel engine can relatively last longer, due to the fact that petrol destroys lubrication and diesel doesn’t.
4. A major advantage of petrol engines is that they are relatively lighter than diesel engines. Engine weight is an important factor which affects speed and performance of a car. This is one of the reasons why some of the fastest cars in the world run on petrol.
5. Carburetor is used to vaporize the fuel mixture in petrol engines and injection pump is used to uplift and forward the fuel to the injectors