report on turbo cooling system

TURBO COOLING ENGINE SYSTEM

2015

Seminar Report

SEMINAR REPORT ON

TURBO COOLING ENGINE SYSTEM Submitted By: Deepak Kumar Dalabehera Guided By: Prof. Swagatika Acharya

Department Of Mechanical Engineering,

Gandhi Institute for Technology, BBSR

TURBO COOLING ENGINE SYSTEM

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CERTIFICATE This is to certify that the seminar on “TURBO COOLING ENGINE SYSTEM” is a bonafide record of the project delivered by “DEEPAK KUMAR DALABEHERA” (Regd.No- 1201298400) under my supervision and guidance, in partial fulfilment of the requirements for the award of Degree of Bachelor of Technology in Mechanical Engineering from GANDHI INSTITUTE FOR TECHNOLOGY, Bhubaneswar for the year 2015-2016.

Seminar Guide

Seminar Coordinator

HOD

TURBO COOLING ENGINE SYSTEM

Seminar Report

2015

ACKNOWLEDGEMENTS

The work presented in this dissertation would not have been possible without the help and support of a large number of people. The author first expresses his heartiest gratitude to his guide and supervisor Prof. Swagatika Acharya, Department of Mechanical Engineering, Gandhi Institute For Technology, Bhubaneswar, Orissa, India for his valuable guidance, help and encouragement in the course of the present work. The successful and timely completion of the work is due to his constant inspiration and constructive criticism. I take this opportunity to express my deepest gratitude to Prof. Amar Das, Co-Ordinator, Department of Mechanical Engineering and also faculty members of the Department of Mechanical Engineering, GIFT, and Bhubaneswar for constant advice, useful discussions, encouragement and support in pursuing the B.Tech work. The help and cooperation received from the Principal and Dean Academic, GIFT, Bhubaneswar are gratefully acknowledged.

Name: Deepak Kumar Dalabehera

Registration no: 1201298400 B.Tech Branch: Mechanical Engineering GIFT, Bhubaneswar

TURBO COOLING ENGINE SYSTEM

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Seminar Report

CONTENTS: TITLE

PAGES

Abstract

i

List of Figures

ii

1.INTRODUCTION

1

2.LITERATURE REVIEW

2

2.1.PURPOSE OF COOLING SYSTEM

3

3.WORKING PRINCIPLE

5

4.BASIC PARTS IN COOLING SYSTEM

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4.1 Radiators

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4.2 Radiator Fans

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4.3 Water Pump

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4.4 Thermostat

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4.5 Pressure Cap and Reserve Tank

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4.6 Fan

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4.7 Heating System

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4.8 Heater Core

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5.DESCRIPTION OF PROCESS 6.GENERALISATION DIFFICULTIES 7.VISUAL INSPECTION 8.COOLING SYSTEM MAINTANCE AND REPAIR 9.ADVANTAGES & DISADVANTAGES 10.CONCLUSION 11.REFERENCES

ABSTRACT

18 21 22 23 25 26 27

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A turbo engine cooling system has separate, complete engine and after cooler coolant loops connected by a linking conduit with a link valve and a fan apparatus providing air flow through both engine and after cooler radiators. The fan apparatus is controllable to vary air flow in a series of discrete cooling levels. An engine cooling control is responsive to a coolant temperature in the engine coolant loop to control the fan apparatus and to derive and output a signal indicative of a desired level of cooling between the selected one and an adjacent one of the discrete cooling levels. An after cooler cooling control is responsive to a coolant temperature in the after cooler coolant loop and the signal output by the engine control to control the link valve so as to vary the temperature of coolant in the engine cooling loop, by controlled mixing of coolant, by controlled mixing of coolant of lower temperature from the after cooler cooling loop, so as to achieve the desired level of cooling indicated by the signal.

i

LIST OF FIGURES Sl. no.

Name Of the Figures

Page no

1

Engine block fig(a)

6

2

Engine block fig(b)

6

3

Radiator

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TURBO COOLING ENGINE SYSTEM

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4

Water pump

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5

Thermostat

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6

Pressure cap and reserve tank

14

7

Fan

15

8

Heating system

16

9

Heater core fig(a)

17

10

Heater core fig(b)

17

ii

CHAPTER 1

1. INTRODUCTION

This is a system of parts and fluids that works together to control an engine’s operation temperature for optimal performance. An internal combustion engine cooling system incorporating a motor-assisted turbofan is disclosed. The turbine-driven fan is increased in rotational speed by energizing a motor attached to the turbine fan shaft from an outside power

TURBO COOLING ENGINE SYSTEM

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source to provide required cooling air flow. A water jacket in the turbo-charger is positioned at the same level or higher than a water jacket in an engine cylinder head. The turbo-charger cooling water circulation passageway includes a water volume or tank positioned at a level higher than the turbo-charger cooling portion, and the volume or tank is connected to a cooling water reservoir tank via a pressure relief valve which is opened when pressure in the volume or tank exceeds a predetermined value to supply cooling water to the volume or tank.

1

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Chapter 2

2. LITERATURE REVIEW Cooling systems for turbo cooling engines of locomotives are known which provide for cooling of the engine and of a turbocharger after cooler. One such system is described in U.S.May 12, 1995 by Teoman Uzkan, one of the inventors of this invention, and issued as U.S. Pat. No. 5,598,705 on Feb. 4, 1997. This system provides separate engine and after cooler coolant loops, each with its own radiator, coolant conduit and pump; but the system also provides a linking conduit with a link valve. When the valve is closed, coolant flows in the engine and after cooler coolant loops are maintained separate, with no coolant mixing; but the valve is capable of opening to permit a controlled mixing of coolant between the loops. With the valve closed, the temperature in the after cooler coolant loop is ordinarily lower than that in the engine coolant loop for maximum fuel economy due to the cooling of turbocharged induction air, but a control is capable of opening the link valve to provide additional cooling capacity in the engine coolant loop by mixing in the lower temperature coolant from the after cooler coolant loop. Thus economy can be achieved in the design of the engine coolant loop, with expansion of cooling capacity by the opening of the link valve in extreme temperature conditions when maximum engine cooling is required; but fuel economy can be maximized during normal temperature conditions by closing the link valve when maximum engine cooling is not required.

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Chapter 3

3. THEORY 3.1.

PURPOSE OF COOLING SYSTEM

Cars and trucks using direct air cooling (without an intermediate liquid) were built over a long period beginning with the advent of mass produced passenger cars and ending with a small and generally unrecognized technical change. Before World War II, water cooled cars and trucks routinely overheated while climbing mountain roads, creating geysers of boiling cooling water. This was considered normal, and at the time, most noted mountain roads had auto repair shops to minister to overheating engines. ACS (Auto Club Suisse) maintains historical monuments to that era on the sustain Pass where two radiator refill stations remain. These have instructions on a cast metal plaque and a spherical bottom watering can hanging next to a water spigot. The spherical bottom was intended to keep it from being set down and, therefore, be useless around the house, in spite of which it was stolen, as the picture shows. During that period, European firms such as Magirus-Deutz built air-cooled diesel trucks, Porsche built air-cooled farm tractors and Volkswagen became famous with air-cooled passenger cars. In the USA, Franklin built air-cooled engines. A typical 4 cylinder vehicle cruising along the highway at around 50 miles per hour, will produce 4000 controlled explosions per minute inside the engine as the spark plugs ignite the fuel in each cylinder to propel the vehicle down the road. Obviously, these explosions produce an enormous amount of heat and, if not controlled, will destroy an engine in a matter of minutes. Controlling these high temperatures is the job of the cooling system. The modern cooling system has not changed much from the cooling systems in the model T back in the '20s. Oh sure, it has become infinitely more reliable and efficient at doing it's job, 3

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but the basic cooling system still consists of liquid coolant being circulated through the engine, then out to the radiator to be cooled by the air stream coming through the front grill of the vehicle. Today's cooling system must maintain the engine at a constant temperature whether the outside air temperature is 110 degrees Fahrenheit or 10 below zero. If the engine temperature is too low, fuel economy will suffer and emissions will rise. If the temperature is allowed to get too hot for too long, the engine will self-destruct.

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TURBO COOLING ENGINE SYSTEM

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Chapter 4

4.

WORKING PRINCIPLE

The cooling system is made up of the passages inside the engine block and heads, a water pump to circulate the coolant, a thermostat to control the temperature of the coolant, a radiator to cool the coolant, a radiator cap to control the pressure in the system, and some plumbing consisting of interconnecting hoses to transfer the coolant from the engine to radiator and also to the car's heater system where hot coolant is used to warm up the vehicle's interior on a cold day. A cooling system works by sending a liquid coolant through passages in the engine block and heads. As the coolant flows through these passages, it picks up heat from the engine. The heated fluid then makes its way through a rubber hose to the radiator in the front of the car. As it flows through the thin tubes in the radiator, the hot liquid is cooled by the air stream entering the engine compartment from the grill in front of the car. Once the fluid is cooled, it returns to the engine to absorb more heat. The water pump has the job of keeping the fluid moving through this system of plumbing and hidden passages.

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TURBO COOLING ENGINE SYSTEM

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Engine block fig(a)

Engine block fig(b) A thermostat is placed between the engine and the radiator to make sure that the coolant stays above a certain preset temperature. If the coolant temperature falls below this temperature, the thermostat blocks the coolant flow to the radiator, forcing the fluid instead through a bypass directly back to the engine. The coolant will continue to circulate like this until it reaches the design temperature, at which point, the thermostat will open a valve and allow the coolant back through the radiator. In order to prevent the coolant from boiling, the cooling system is designed to be pressurized. Under pressure, the boiling point of the coolant is raised considerably. However, too much pressure will cause hoses and other parts to burst, so a system is needed to relieve pressure if 6 it exceeds a certain point. The job of maintaining the pressure in the cooling system belongs

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to the radiator cap. The cap is designed to release pressure if it reaches the specified upper limit that the system was designed to handle. Prior to the '70s, the cap would release this extra pressure to the pavement. Since then, a system was added to capture any released fluid and store it temporarily in a reserve tank. This fluid would then return to the cooling system after the engine cooled down. This is what is called a turbo cooling system. Temperature can determine just how much power an engine can make, how efficiently it will run, and whether or not it will hold together. Excessive cooling system temperatures can cause hoses to burst, head gaskets to blow and even cylinder heads and engine blocks to warp; the fact that they'll lose significant amounts of power goes without saying. It's not good. That's why it's important to keep water temperatures under control. Common cool-down methods include larger frontal area and/or thicker aluminum radiators, which have the ability to dissipate more heat quickly, but can also be fairly expensive. Sometimes adding a larger or secondary cooling fan will help alleviate low-speed or idling cooling issues. But even adding another fan or a larger one will cost you a bit of cash and may cause problems when it comes time to fitting it in place. Either way, if your engine is overheating, it has to be taken care of otherwise you'll end up with expensive problems that make the price of an aluminum radiator seem more on par with the amount of change you've got under your couch cushion. The modern day gasoline engine isn't all that efficient, at least not as much as we'd like it to be. Fuel energy that could potentially be used to produce additional power is constantly lost through the cooling system. The process is called heat rejection, and if it didn't take place, thermal breakdown of the pistons, cylinders and cylinder head could occur. Call it a tradeoff. Cooling is also important when it comes to the ignition process and the combustion chamber. As combustion chamber temperatures increase, higher octane’s of fuel or retarded spark timing are needed. The density of the air/fuel ratio is also decreased as heat rises. To compensate, some vehicles pull out ignition timing automatically as cooling system temperatures rise. In other words, high temperatures rob horsepower. We're not typically fans of miracle products that come in a bottle, or a can for that matter. But over the years we've become accustomed to using cooling system wetting agents, as they've been proven to work almost every time. Unlike ring sealers in a can and other mysterious leak 7 sealing products that never seem to work, cooling system additives generally do work. But toanswer the question as to just how well some of these additives get the job done and which

TURBO COOLING ENGINE SYSTEM

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reigns supreme, we decided to put four of them to the test.Our test apparatus took the form of an EG Honda Civic with an H22A4 Prelude engine stuffed into place. A classic recipe for overheating since many transplant owners fail to upgrade the radiator despite the more than 40-percent larger displacement engine not to mention its sheer physical size increase. Our test vehicle took the necessary precautions - sort of. A thicker Del Sol Si VTEC radiator was swapped into place as was a higher flowing cooling fan, but that doesn't stop the Civic from escalating cooling system temps. With a 50/50 mix of Honda antifreeze and distilled water, temperatures soared to 215 F routinely while sitting in the drive-thru, and never really dropped below the 200 mark even under normal low engine speed driving conditions. Cylinder head temperatures were equally as scorching in the case of our Honda measuring in at nearly 210 F. As such, our radiator proved rather inefficient, only able to drop the system's temperature by a factor of five percent. For our test we rounded up four of the most popular cooling additive products on the market: Red Line Water Wetter, DEI Radiator Relief, Hy-per Lube Super Coolant, and Justice Brothers Radiator Cooler. We tested these products mixed with both a 30/70 antifreeze/water mixture and mixed with water alone. The key to any successful test is keeping as many of the variables the same as possible, and performing as many tests as possible. Two days and nearly 300 miles later and we had our results, and some nasty burn marks on our arms. Note to self: allow more than two days when changing radiator fluid almost 10 times. Aside from outside air temperatures, which remained fairly constant during our testing, we were able to control almost everything else. We kept to the same roads, and stabilized load conditions by repeating similar engine and vehicle speeds for each test. We performed four tests for each mixture: Low rpm, low mph street driving; 4000rpm, 75mph freeway speeds; 5000rpm hill climbs; and extended idling. We also performed temperature readings for both radiator inlet and outlet temperatures and cylinder head temperatures. Now would be a good time to mention that none of these products are designed to perform miracles, and if your radiator isn't up to the task, don't expect anything but a new or larger radiator to fix the problem.

8 All of them, but to different degrees and in slightly different ways. But there were stipulations. When mixed with coolant, our temperature drops were negligible, but still there. But with straight water, the temperature drops were nothing short of impressive. We expected this.

TURBO COOLING ENGINE SYSTEM

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There's no glycol-based antifreeze, or any liquid cooling agent for that matter, that we're aware of that can dissipate or transfer heat as well as plain old water. But you can't run plain old water, at least not without rusting or destroying your engine.

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Chapter 5 5. BASIC PARTS IN TURBO COOLING SYSTEM

TURBO COOLING ENGINE SYSTEM

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5.1Radiator: The radiator core is usually made of flattened aluminum tubes with aluminum strips that zigzag between the tubes. These fins transfer the heat in the tubes into the air stream to be carried away from the vehicle. On each end of the radiator core is a tank, usually made of plastic that covers the ends of the radiator, On most modern radiators, the tubes run horizontally with the plastic tank on either side. On other cars, the tubes run vertically with the tank on the top and bottom. On older vehicles, the core was made of copper and the tanks were brass. The new aluminum-plastic system is much more efficient, not to mention cheaper to produce. On radiators with plastic end caps, there are gaskets between the aluminum core and the plastic tanks to seal the system and keep the fluid from leaking out. On older copper and brass radiators, the tanks were brazed (a form of welding) in order to seal the radiator.

(Radiator) The tanks, whether plastic or brass, each have a large hose connection, one mounted towards the top of the radiator to let the coolant in, the other mounted at the bottom of the radiator on the other tank to let the coolant back out. On the top of the radiator is an additional opening 10 that is capped off by the radiator cap. Another component in the radiator for vehicles with an automatic transmission is a separate tank mounted inside one of the tanks. Fittings connect this inner tank through steel tubes to the automatic transmission. Transmission fluid is piped through this tank inside a tank to be cooled by the coolant flowing past it before returning the transmission.

5.2 Radiator Fans:-

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Mounted on the back of the radiator on the side closest to the engine is one or two electric fans inside a housing that is designed to protect fingers and to direct the air flow. These fans are there to keep the air flow going through the radiator while the vehicle is going slow or is stopped with the engine running. If these fans stopped working, every time you came to a stop, the engine temperature would begin rising. On older systems, the fan was connected to the front of the water pump and would spin whenever the engine was running because it was driven by a fan belt instead of an electric motor. In these cases, if a driver would notice the engine begin to run hot in stop and go driving, the driver might put the car in neutral and rev the engine to turn the fan faster which helped cool the engine. Racing the engine on a car with a malfunctioning electric fan would only make things worse because you are producing more heat in the radiator with no fan to cool it off. The electric fans are controlled by the vehicle's computer. A temperature sensor monitors engine temperature and sends this information to the computer. The computer determines if the fan should be turned on and actuates the fan relay if additional air flow through the radiator is necessary. If the car has air conditioning, there is an additional radiator mounted in front of the normal radiator. This "radiator" is called the air conditioner condenser, which also needs to be cooled by the air flow entering the engine compartment. You can find out more about the air conditioning condenser by going to our article on Automotive Air Conditioning. As long as the air conditioning is turned on, the system will keep the fan running, even if the engine is not running hot. This is because if there is no air flow through the air conditioning condenser, the air conditioner will not be able to cool the air entering the interior.

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5.3 Water Pump: Water pump is a simple device that will keep the coolant moving as long as the engine is running. It is usually mounted on the front of the engine and turns whenever the engine is running. The water pump is driven by the engine through one of the following: 

A fan belt that will also be responsible for driving an additional component like an alternator or power steering pump.



A serpentine belt, which also drives the alternator, power steering pump and AC compressor among other things.

TURBO COOLING ENGINE SYSTEM



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The timing belt that is also responsible for driving one or more camshafts.

The water pump is made up of a housing, usually made of cast iron or cast aluminum and an impeller mounted on a spinning shaft with a pulley attached to the shaft on the outside of the pump body. A seal keeps fluid from leaking out of the pump housing past the spinning shaft. The impeller uses centrifugal force to draw the coolant in from the lower radiator hose and send it under pressure into the engine block. There is a gasket to seal the water pump to the engine block and prevent the flowing coolant from leaking out where the pump is attached to the block.

(Water pump)

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5.4 THERMOSTAT:The thermostat's main job is to allow the engine to heat up quickly, and then to keep the engine at a constant temperature. It does this by regulating the amount of water that goes through the radiator. At low temperatures, the outlet to the radiator is completely blocked -all of the coolant is recirculates back through the engine. Once the temperature of the coolant rises to between 180 and 195 F (82 - 91 C), the thermostat starts to open, allowing fluid to flow through the radiator. By the time the coolant reaches 200 to 218 F (93 - 103 C), the thermostat is open all the way.

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(Thermostat) If anyone ever has the chance to test one, a thermostat is an amazing thing to watch because what it does seems impossible. You can put one in a pot of boiling water on the stove. As it heats up, its valve opens about an inch, apparently by magic! If you'd like to try this yourself, go to a car parts store and buy one for a couple of bucks. The secret of the thermostat lies in the small cylinder located on the engine-side of the device. This cylinder is filled with a wax that begins to melt at around 180 F (different thermostats open at different temperatures, but 180 F is a common one). A rod connected to the valve presses into this wax. When the wax melts, it expands significantly, pushing the rod out of the cylinder and opening the valve.

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5.5 Pressure cap and reserve tank:As coolant gets hot, it expands. Since the cooling system is sealed, this expansion causes an increase in pressure in the cooling system, which is normal and part of the design. When coolant is under pressure, the temperature where the liquid begins to boil is considerably higher. This pressure, coupled with the higher boiling point of ethylene glycol, allows the coolant to safely reach temperatures in excess of 250 degrees.

TURBO COOLING ENGINE SYSTEM

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(Pressure cap and pressure tank) The radiator pressure cap is a simple device that will maintain pressure in the cooling system up to a certain point. If the pressure builds up higher than the set pressure point, there is a spring loaded valve, calibrated to the correct Pounds per Square Inch (psi), to release the pressure. When the cooling system pressure reaches the point where the cap needs to release this excess pressure, a small amount of coolant is bled off. It could happen during stop and go traffic on an extremely hot day, or if the cooling system is malfunctioning. If it does release pressure under these conditions, there is a system in place to capture the released coolant and store it in a plastic tank that is usually not pressurized. Since there is now less coolant in the system, as the engine cools down a partial vacuum is formed. The radiator cap on these closed systems has a secondary valve to allow the vacuum in the cooling system to draw the coolant back into the radiator from the reserve tank (like pulling the plunger back on a hypodermic needle) There are usually markings on the side of the plastic tank marked Full-Cold, and Full Hot. 14 When the engine is at normal operating temperature, the coolant in the translucent reserve tank should be up to the Full-Hot line. After the engine has been sitting for several hours and is cold to the touch, the coolant should be at the Full-Cold line.

5.6 FAN:Like the thermostat, the cooling fan has to be controlled so that it allows the engine to maintain a constant temperature. Front-wheel drive cars have electric fans because the engine is usually mounted transversely, meaning the output of the engine points toward the side of the car. The fans are controlled either with a thermostatic switch or by the engine computer, and they turn on when off when the temperature drops below that point.

TURBO COOLING ENGINE SYSTEM

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(fan) Rear-wheel drive cars with longitudinal engines usually have engine-driven cooling fans. These fans have a thermostatically controlled viscous clutch. This clutch is positioned at the hub of the fan, in the airflow coming through the radiator. This special viscous clutch is much like the viscous coupling sometimes found in all-wheel drive cars.

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5.7 HEATING SYSTEM:You may have heard the advice that if you car is overheating, open all the windows and run the heater with the fan going at full blast. This is because the heating system is actually a secondary cooling system that mirrors the main cooling system on your car.

TURBO COOLING ENGINE SYSTEM

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(Heating system) The heater core, which is located in the dashboard of your car, is really a small radiator. The heater fan blows air through the heater core and into the passenger compartment of your car.

5.8 HEATER CORE:The hot coolant is also used to provide heat to the interior of the vehicle when needed. This is a simple and straight forward system that includes a heater core, which looks like a small version of a radiator, connected to the cooling system with a pair of rubber hoses. One hose brings hot coolant from the water pump to the heater core and the other hose returns the coolant to the top of the engine. There is usually a heater control valve in one of the hoses to block the flow of coolant into the heater core when maximum air conditioning is called for. A fan, called a blower, draws air through the heater core and directs it through the heater ducts to the interior of the car. Temperature of the heat is regulated by a blend door that mixes cool outside air, or sometimes air conditioned air with the heated air coming through the heater core. This blend door allows you to control the temperature of the air coming into

16 the interior. Other doors allow you to direct the warm air through the ducts on the floor, the defroster ducts at the base of the windshield, and the air conditioning ducts located in the instrument panel.

TURBO COOLING ENGINE SYSTEM

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Heater core fig(a)

Seminar Report

Heater core fig(b)

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Chapter 6 6. DESCRIPTION OF PROCESS: Circulation:The coolant follows a path that takes it from the water pump, through passages inside the engine block where it collects the heat produced by the cylinders. It then flows up to the cylinder head (or heads in a V type engine) where it collects more heat from the combustion

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chambers. It then flows out past the thermostat (if the thermostat is opened to allow the fluid to pass), through the upper radiator hose and into the radiator. The coolant flows through the thin flattened tubes that make up the core of the radiator and is cooled by the air flow through the radiator. From there, it flows out of the radiator, through the lower radiator hose and back to the water pump. By this time, the coolant is cooled off and ready to collect more heat from the engine. The capacity of the system is engineered for the type and size of the engine and the work load that it is expected to undergo. Obviously, the cooling system for a larger, more powerful V8 engine in a heavy vehicle will need considerably more capacity than a compact car with a small 4 cylinder engine. On a large vehicle, the radiator is larger with many more tubes for the coolant to flow through. The radiator is also wider and taller to capture more air flow entering the vehicle from the grill in front. Antifreeze:The use of water cooling carries the risk of damage from freezing. Automotive and many other engine cooling applications require the use of a water and antifreeze mixture to lower the freezing point to a temperature unlikely to be experienced. Antifreeze also inhibits corrosion from dissimilar metals and can increase the boiling point, allowing a wider range of water cooling temperatures. Its distinctive odor also alerts operators to cooling system leaks and problems that would go unnoticed in a water-only cooling system. The heated water can also be used to warm the air conditioning system inside the car, if so desired.

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Radiator Pressure Cap Test:A radiator pressure cap is designed to maintain pressure in the cooling system at a certain maximum pressure. If the cooling system exceeds that pressure, a valve in the cap opens to bleed the excessive pressure into the reserve tank. Once the engine has cooled off, a negative pressure begins to develop in the cooling system. When this happens, a second valve in the cap allows the coolant to be siphoned back into the radiator from the reserve tank. If the cap should fail, the engine can easily overheat. A pressure test of the radiator cap is a quick way

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to tell if the cap is doing its job. It should be able to hold its rated pressure for two minutes. Since radiator caps are quite inexpensive, I would recommend replacing it every 3 years or 36,000 miles, just for added insurance. Make absolutely sure that you replace it with one that is designed for your vehicle. Thermostat Check For Proper Opening And Closing:This step is only necessary if you are having problems with the cooling system. A thermostat is designed to open at a certain coolant temperature. To test a thermostat while it is still in the engine, start the engine and let it come to normal operating temperature (do not let it overheat). If it takes an unusually long time for the engine to warm up or for the heater to begin delivering hot air, the thermostat may be stuck in the open position. If the engine does warm up, shut it off and look for the two radiator hoses. These are the two large hoses that go from the engine to the radiator. Feel them carefully (they could be very hot). If one hose is hot and the other is cold, the thermostat may be stuck closed. If you are having problems and suspect the thermostat, remove it and place it in a pot of water. Bring the water to a boil and watch the thermostat. You should see it open when the water reaches a boil. Most thermostats open at about 195 degrees Fahrenheit. An oven thermometer in the water should confirm that the thermostat is working properly. Pressure Test To Identify Any External Leaks:Pressure testing the cooling determines where a leak is located. This test is only performed after the cooling system has cooled sufficiently to allow you to safely remove the pressure 19

cap. Once you are sure that the cooling system is full of coolant, a cooling system pressure tester is attached in place of the radiator cap. The tester is than pumped to build up pressure in the system. There is a gauge on the tester indicating how much pressure is being pumped. You should pump it to the pressure indicated on the pressure cap or to manufacturer's specs .Once pressure is applied, you can begin to look for leaks. Also watch the gauge on the tester to see if it loses pressure. If the pressure drops more than a couple of pounds in two minutes, there is likely a leak somewhere that may be hidden. It is not always easy to see where a leak is originating from. It is best to have the vehicle up on a lift so you can look over everything with a shop light or flashlight.

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Chapter 7 7. GENERALISATION DIFFICULTIES It is difficult to make generalizations about air-cooled and liquid-cooled engines. Aircooled Volkswagen kombis are known for rapid wear in normal use and sometimes sudden failure when driven in hot weather. Alternately, air-cooled Deutz diesel engines are known for reliability even in extreme heat, and are often used in situations where the engine runs unattended for months at a time.

TURBO COOLING ENGINE SYSTEM

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Similarly, it is usually desirable to minimize the number of heat transfer stages in order to maximize the temperature difference at each stage. However, Detroit Diesel 2-stroke cycle engines commonly used oil cooled by water, with the water in turn cooled by air. The coolant used in many liquid-cooled engines must be renewed periodically, and can freeze at ordinary temperatures thus causing permanent engine damage. Air-cooled engines do not require coolant service, and do not suffer engine damage from freezing, two commonly-cited advantages for air-cooled engines. However, coolant based on propylene glycol is liquid to -55 °C, colder than is encountered by many engines; shrinks slightly when it crystallizes, thus avoiding engine damage; and has a service life over 10,000 hours, essentially the lifetime of many engines. It is usually more difficult to achieve low emissions or low noise from an air-cooled engine, two more reasons most road vehicles use liquid-cooled engines. It is also often difficult to build large air-cooled engines, so nearly all air-cooled engines are under 500 kW, whereas large liquid-cooled engines exceed 80 MW.

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Chapter 8 8. VISUAL INSPECTION: What you are looking for is the condition of the belts and hoses. The radiator hoses and heater hoses are easily inspected just by opening the hood and looking. You want to be sure that the hoses have no cracking or splitting and that there is no bulging or swelling at the ends. If there is any sign of problems, the hose should be replaced with the correct part number for the year, make and model of the vehicle. Never use a universal hose unless it is an emergency and a proper molded hose is not available.

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Heater hoses are usually straight runs and are not molded, so a universal hose is fine to use and often is all that is available. Make sure that you use the proper inside diameter for the hose being replaced. For either the radiator hoses or the heater hoses, make sure that you route the replacement hose in the same way that the original hose was running. Position the hose away from any obstruction that can possibly damage it and always use new hose clamps. After you refill the cooling system with coolant, do a pressure test to make sure that there are no leaks. On older vehicles, the water pump is driven by a V belt or serpentine belt on the front of the engine that is also responsible for driving the alternator, power steering pump and air conditioner compressor. These types of belts are easy to inspect and replace if they are worn. You are looking for dry cracking on the inside surface of the belt. On later vehicles, the water pump is often driven by the timing belt. This belt usually has a specific life expectancy at which time it must be replaced to insure that it does not fail. Since the timing belt is inside the engine and will require partial engine disassembly to inspect, it is very important to replace it at the correct interval. Since the labor to replace this belt can be significant, it is a good idea to replace the water pump at the same time that the belt is replaced. This is because 90 percent of the labor to replace a water pump has already been done to replace the timing belt. It is simply good insurance to replace the pump while everything is apart.

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Chapter 9 9. Cooling System Maintenance and Repair An engine that is overheating will quickly self-destruct, so proper maintenance of the cooling system is very important to the life of the engine and the trouble free operation of the cooling system in general. The most important maintenance item is to flush and refill the coolant periodically. The reason for this important service is that anti-freeze has a number of additives that are designed to prevent corrosion in the cooling system. This corrosion tends to accelerate when several different types of metal interact with each other. The corrosion causes scale that eventually

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builds up and begins to clog the thin flat tubes in the radiator and heater core causing the engine to eventually overheat. The anti-corrosion chemicals in the antifreeze prevent this, but they have a limited life span. Newer antifreeze formulations will last for 5 years or 150,000 miles before requiring replacement. These antifreezes are usually red in color and are referred to as "Extended Life" or "Long Life" antifreeze. GM has been using this type of coolant in all their vehicles since 1996. The GM product is called "Dex-Cool". Most antifreeze used in vehicles however, is green in color and should be replaced every two years or 30,000 miles, whichever comes first. You can convert to the new long life coolant, but only if you completely flush out all of the old antifreeze. If any green coolant is allowed to mix with the red coolant, you must revert to the shorter replacement cycle. Look for a shop that can reverse-flush the cooling system. This requires special equipment and the removal of the thermostat in order to do the job properly. This type of flush is especially important if the old coolant looks brown or has scale or debris floating around in it. If you remove the thermostat for a reverse flush, always replace it with a new thermostat of the proper temperature. It is cheap insurance. The National Automotive Radiator Service Association (NARSA) recommends that motorists have a seven-point preventative cooling system maintenance check at least once every two years. The seven-point program is designed to identify any areas that need attention. 23 It consists of: 

a visual inspection of all cooling system components, including belts and hoses

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a radiator pressure cap test to check for the recommended system pressure level

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a thermostat check for proper opening and closing

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a pressure test to identify any external leaks to the cooling system parts; including the radiator, water pump, engine coolant passages, radiator and heater hoses and heater core

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an internal leak test to check for combustion gas leakage into the cooling system

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an engine fan test for proper operation

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a system power flush and refill with car manufacturer's recommended concentration of coolant

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CHAPTER 10

10.1 ADVANTAGES: There is no leakage in this cooling process. This system can be used also in cold climate. Uniform cooling of cylinder, cylinder head and valves takes place. Engine is less noisy than other cooling systems.

TURBO COOLING ENGINE SYSTEM

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10.2 DISADVANTAGES: Used in aeroplanes engines where the engines are exposed to air directly. It absorbs considerable power. If it fails it causes severe damage of engine. It is more costly and requires more maintenance.

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CONCLUSION

It is concluded that this system help coolants higher specific heat capacity, density, and thermal conductivity. This allows water to transmit heat over greater distances with much less volumetric flow and reduced temperature difference. For cooling CPU cores, this is its primary advantage: the tremendously increased ability to transport heat away from source to a secondary cooling surface allows for large, more optimally designed radiators rather than small, inefficient fins mounted on or near a heat source such as a CPU core. The "water jacket" around an engine is also very effective at deadening mechanical noises, which makes the engine quieter.

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REFERENCES Apr 9, 1999 Oct 24, 2000 Caterpillar Inc. cooling system for a machine May 21, 1999 Dec 12, 2000, Caterpillar Inc. Turbo engine cooling system with two two-pass radiators Nov 6, 1998 Dec 12, 2000 Caterpillar Inc. Turbo engine cooling system with two-pass radiator Dec 1, 2000 Nov 13, 2001 Caterpillar Inc. Intake air temperature control system Feb 13, 2004 May 23, 2006 Deere & Company cooling system for a vehicle Dec 6, 2004 Jun 13, 2006 Southwest Research Institute.

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