Lubrication and Cooling System in an Engine

BRANCH-MECHANICAL ENGG.

SEMESTER-6^TH SEM

NAME-Er.MANAS RANJAN MOHANTA

Upon completion of this lesson, the students will be able to:�

Upon completion of this lesson, the students will be able to:

1) Identify where the cooling occurs in an engine

2) Identify where lubrication in an engine occurs

3) List the parts in an engine where cooling and lubrication occurs

4) Know the importance of keeping an engine lubricated

There are a few safety precautions that need to be followed when checking the lubrication and cooling systems in an engine�

1. The engine should be cold before you start.

2. The cap on the top of almost every car or truck radiator (or on the separate coolant reservoir) is designed for safety — first letting any built- up pressure escape slowly — before the cap is completely removed.

3. Don’t touch the oil because it maybe hot.

4. Wear gloves or use a rag.

5. Wear safety glasses.

Can anyone give me another?

Does anyone know the importance of lubrication and cooling systems in an engine?

• The lubrication and cooling system of an internal- combustion engine is very important. If the lubricating system should fail, not only will the engine stop, but many of the parts are likely to be damage beyond repair. Coolant protects your engine from freezing or overheating.

What lubrication system does for an engine.

1. The job of the lubrication system is to distribute oil to the moving parts to reduce friction between surfaces which rub against each other.
2. An oil pump is located on the bottom of the engine.

3. The pump is driven by a worm gear off the main exhaust valve cam shaft.

4. The oil is pumped to the top of the engine inside a feed line.
5. Small holes in the feed line allow the oil to drip inside the crankcase.
6. The oil drips onto the pistons as they move in the cylinders, lubricating the surface between the piston and cylinder.
7. The oil then runs down inside the crankcase to the main bearings holding the crankshaft.
8. Oil is picked up and splashed onto the bearings to lubricate these surfaces.
9. Along the outside of the bottom of the crankcase is a collection tube which gathers up the used oil and returns it to the oil pump to be circulated again.

Proper lubrication of an engine is a complex process.

Motor oil must perform many functions under many different operating conditions. The primary functions of oil are listed below:

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1. Provide a barrier between moving parts to reduce friction, heat buildup, and wear.

2. Disperse heat. Friction from moving parts and combustion of fuel produce heat that must be carried away.

3. Absorb and suspend dirt and other particles. Dirt and carbon particles need to be carried by the oil to the oil filter where they can be trapped.

4. Neutralize acids that can build up and destroy polished metal surfaces.

5. Coat all engine parts. Oil should have the ability to leave a protective coating on all parts when the engine is turned off to prevent rust and corrosion.

6. Resist sludge and varnish buildup. Oil must be able to endure extreme heat without changing in physical properties or breaking down.

7. Stay fluid in cold weather; yet remain thick enough to offer engine

What the cooling system does for an engine.

1. Although gasoline engines have improved a lot, they are still not very efficient at turning chemical energy into mechanical power.
2. Most of the energy in the gasoline (perhaps 70%) is converted into heat, and it is the job of the cooling system to take care of that heat. In fact, the cooling system on a car driving down the freeway dissipates enough heat to heat two average-sized houses!
3. The primary job of the cooling system is to keep the engine from overheating by transferring this heat to the air, but the cooling system also has several other important jobs.

4. The engine in your car runs best at a fairly high temperature.

5. When the engine is cold, components wear out faster, and the engine is less efficient and emits more pollution.

6. So another important job of the cooling system is to allow the engine to heat up as quickly as possible, and then to keep the engine at a constant temperature.

Cooling systems consist of three main parts:

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1. Pumping

• Your cooling system's pumping function is handled by its water pump, which keeps the coolant mixture moving.

The main water pump is gear- or belt-driven but, in many cars, a secondary electric water pump is used for improved flow and cooling.

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Cooling systems consist of three main parts:

2. Piping

• Your cooling system's piping consists of all hoses, any control valves, the heater core, the radiator and the expansion tank. Because of the materials used and the constant contact with coolant, all parts in this system deteriorate more from time than use.
• Maintenance of cooling system piping consists of scheduled coolant replacement, replacement of all hoses on a regular basis and replacement of any plugged or leaking parts.

• All hoses should be checked at least twice a year for abrasions, cracks, flexibility and evidence of leakage. Whenever the coolant is drained for replacement or during engine repairs, any suspect hoses should be replaced. All hoses should be replaced at least every few years.
• Radiators, expansion tanks, heater cores and control valves are normally only replaced due to leakage or plugging. The condition of these parts should be assessed by a professional since proper functioning is critical to many other systems within your car.

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Cooling systems consist of three main parts:

3. Temperature Control

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• Your cooling system's temperature controls include all coolant temperature sensors, thermostat, radiator or expansion tank cap, cooling fan(s) and fan clutch (if equipped). These cooling system parts function primarily independent of the engine but control the engine either through cooling or by sending control signals to your car's electronic systems.
• The thermostat is a spring-loaded valve that opens and closes based on the temperature of the coolant flowing through it. A high temperature reading followed by a drop to normal temperature (or a continuously low temperature) is a common first sign of a sticking thermostat. However, many other conditions may cause these symptoms, so you need to know how to eliminate each possibility.
• The radiator or expansion tank cap is also a spring-loaded valve reacting to system pressure. It serves to maintain proper system coolant level at predetermined pressures. It must always be replaced with an exact replacement cap with the same pressure setting. Never use other caps except for short-term emergencies!

Liquid Cooled System

• In a liquid cooled system, heat is carried away by the use of a heat absorbing coolant that circulates through the engine, especially around the combustion chamber in the cylinder head area of the engine block. The coolant is pumped through the engine, then after absorbing the heat of combustion is circulated to the radiator where the heat is transferred to the atmosphere. The cooled liquid is then transferred back into the engine to repeat the process.

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Maintenance of your cooling system

• Maintenance of your cooling system sensors is virtually impossible since there's nothing really to "maintain". Keeping them clean both internally (coolant replacement) and externally (engine cleaning) is the best way to ensure trouble-free driving. Checking and replacing all parts at the factory-recommended time or mileage limits helps as well.

Is there any questions?

Lubrication and Cooling System

• The lubrication system of an internal-combustion engine is very important. If the lubricating system should fail, not only will the engine stop, but many of the parts are likely to be damaged beyond repair.

• The only purpose of the engine's cooling system is to remove excess heat from the engine, to keep the engine operating temperature at its most efficient level, and to get the engine up to the correct temperature as soon as possible after starting. A cooling system is also required to prevent the internal engine parts from melting from the heat of the burning fuel.

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Engine Failures

• Does anyone know the how many engine failures are attributed to cooling system failure?

-Over 50% of engine failures can be attributed to cooling system failure.

Thing needed to repair a cooling system

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• Can anyone list some of the things needed to repair a cooling system?

- Coolant � - Water Pump � - Water Pump Drive Belt (timing, V-, or flat) � - Hoses (upper & lower radiator, bypass, heater, manifold coolant, etc.)

- Radiator � - Expansion Tank � - Heater Core� - Control Valves� - Temperature Sensors� - Radiator Cap and/or Expansion Tank Cap � - Fan Clutch

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• Can anyone tell me how important a lubrication system is in an engine?