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TERM PAPER

Topic: Otto Cycle Vs Diesel Cycle

SUMMITTED TO: SUBMITTED BY:

MR.TUKESH SONI . HAZRAT BELAL

. ROLL NO:RB4912-A05.

REG NO:10901869

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ACKNOWLEDGEMENT

I HAVE GREAT SENSE OF HAPPINESS AND PRIDE IN WRITING THIS TERM PAPER. I HAVE WITNESSED THE UNTIRING EFFORTS MADE BY MY THERMODYNAMICS TEACHER MR. TUKESH SONI SIR. I WOULD LIKE TO THANK MY TEACHERS IN GIVING ME IDEAS FOR MAKING THIS TERM PAPER. I WOULD LIKE TO THANK THE AUTHOR OF THE BOOKS WHICH I USED FOR REFERENCE. I WOULD LIKE TO THANK THE HOST AND CREATOR OF THE WEB SITES FROM WHICH I GOT THE INFORMATION ABOUT THE TERM PAPER

TABLE OF CONTENTS:-

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S.No Contents Page no

1) Introduction 4

2) What is Otto Cycle 6

3) Discussion about Otto Cycle 7

4) Otto Cycle operations 8

5) What is diesel Cycle 12

6) Design Of Diesel Cycle 15

7) Otto Cycle Vs Diesel Cycle 18

8) Compare of Otto Cycle & Diesel cycle 22

9) Controlling Power 28

10) Conclusion 31

11) References 32

Introduction

In these three articles we studied about Otto cycle, diesel cycle and dual cycle and looked at their thermal efficiency. In this article we will take a collective look at these three cycles in order to compare and contrast them, so that we can come to know the relative advantages and disadvantages of these cycles.

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What is Otto cycle?

An Otto cycle is an idealized thermodynamic cycle which describes the functioning of a typical reciprocating piston engine.

The idealized four-stroke Otto cycle p-V diagram: the intake (A) stroke performed by an isobaric expansion, followed by an adiabatic

compressedstroke.Through the combustion of fuel, heat is added in an isochoric process, followed by an adiabatic expansion process, characterizing the power

(C) stroke. The cycle is closed by the exhaust (D) stroke, characterize byisochor cooling and isobaric compression processes.

History and invention of Otto Cycle

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Nikolaus Otto was born in Holzhausen, Germany on 10th June 1832. In his early years he began experimenting with gas engines and completed his first atmospheric engine in 1867. In 1872 he joined with Gottlieb Daimler and Wilhelm Maybach and in 1876 developed the first 4-stroke cycle internal combustion engine based on principles patented in 1862 by Alphonse Beau de Rochas. Although Otto's patent claim for the 'Otto Cycle' was invalidated in 1886, his engineering work led to the first practical use of the 4-stroke cycle which was to provide the driving force for transportation for over a century. Nikolaus Otto died on 26th January 1891.

Discussion about Otto Cycle

Several engines may be approximated by an Otto cycle, such as petrol engine and gas engine. The otto cycle is an ideal air standard cycle which consists of four processes:

1 to 2: Isentropic compression 2 to 3: Reversible constant volume heating 3 to 4: Isentropic expansion 4 to 1: Reversible constant volume cooling

The thermal efficiency of an Otto cycle with a perfect gas as working fluid is:

It can be shown that:

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where,r= V1/V2= Compression ratio n=1 - = a constant depending on specific heat capacity

The Wright brothers used a gasoline powered, four-stroke, internal combustion engine to power their aircraft. In an internal combustion engine, fuel and air are ignited inside a cylinder. The hot exhaust gas pushes a piston in the cylinder which is connected to a crankshaft to produce power. The burning of fuel is not a continuous process, but occurs very quickly at regular time intervals. Between ignitions, the engine parts move in a repeated sequence called a cycle. The engine is called a four-stroke engine because there are four movements (strokes) of the piston during one cycle. The brothers' design was based on early automobile

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engine designs which used the Otto cycle, developed by the German, Dr. N. A. Otto, in 1876.

The brothers' design is very simple by today's standards, so it is a good engine for students to study to learn the fundamentals of engine operation. There are two main parts to engine operation: the mechanical operation of the engine parts, and the thermodynamics through which the engine produces work and power. On this page we will discuss the basic thermodynamic principles and on a separate page we present the thermodynamic analysis that allows you to design and predict engine performance.

Thermodynamics is a branch of physics which deals with the energy and work of a system. It was born in the 19th century as scientists were first discovering how to build and operate steam engines. Thermodynamics deals only with the large scale response of a system which we can observe and measure in experiments. The basic ideas of thermodynamics are taught in high school physics classes, so the Wright brothers knew and used these concepts, particularly in their engine design.

We have broken the Otto cycle into six numbered stages based on the mechanical operation of the engine. At each stage, we show a cut through the cylinder to reveal the movement of the piston and the amount of the gas volume created by the head of the piston and the cylinder to the right of the piston head. On the figure we show a plot of pressure versus gas volume throughout one cycle. The cycle begins at the lower left with Stage 1 being the beginning of the intake stroke of the engine. The pressure is near atmospheric pressure and the gas volume is at a minimum with the piston far to the right in the cylinder. Between Stage 1 and Stage 2 the piston is moved to the left, the pressure remains constant, and the gas volume increases as fuel/air mixture is drawn into the cylinder through the intake valve (red). Stage 2 begins the compression stroke of the engine with the closing of the intake valve. Between Stage 2 and Stage 3, the piston moves back to the right, the gas volume decreases, and the pressure increases because work is done on the gas by the piston. Stage 3 is the beginning of the combustion of the fuel/air mixture. The combustion occurs very quickly and the volume remains constant. Heat is released during combustion which increases both the temperature and the pressure, according to the equation of state. Stage 4 begins the power stroke of the engine. Between Stage 4 and Stage 5, the piston moves back to the left, the volume in increased, and the pressure falls as work is done by

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the gas on the piston. At Stage 5 the exhaust valve (blue) is opened and the residual heat in the gas is exchanged with the surroundings. The volume remains constant and the pressure adjusts back to atmospheric conditions. Stage 6 begins the exhaust stroke of the engine during which the piston moves back to the right, the volume decreases and the pressure remains constant. At the end of the exhaust stroke, conditions have returned to Stage 1 and the process repeats itself.

During the cycle, work is done on the gas by the piston between stages 2 and 3. Work is done by the gas on the piston between stages 4 and 5. The difference between the work done by the gas and the work done on the gas is shown in yellow and is the work produced by the cycle. The work times the rate of the cycle (cycles per second) is equal to the power produced by the engine. The area enclosed by the cycle on a p-V diagram is proportional to the work produced by the cycle. On this page we have shown an ideal Otto cycle in which there is no heat entering (or leaving) the gas during the compression and power strokes, no friction losses, and instantaneous burning occurring at constant volume. In reality, the ideal cycle does not occur and there are many losses associated with each process. These losses are normally accounted for by efficiency factors which multiply and modify the ideal result. For a real cycle, the shape of the p-V diagram is similar to the ideal, but the area (work) is always less than the ideal value.

Otto 4-Stroke Cycle Operation

The induction stroke is generally considered to be the first stroke of the Otto 4-Stroke Cycle. At this point in the cycle, the inlet valve is open and the exhaust valve is closed. As the piston travels down the cylinder, a new charge of fuel/air mixture is drawn through the inlet port into the cylinder.

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The adjacent figure shows the engine crankshaft rotating in a clockwise direction. Fuel is injected through a sequentially controlled port injector just behind the inlet valve.

From a theoretical perspective, each of the strokes in the cycle complete at Top Dead Centre (TDC) or Bottom Dead Centre (BDC), but in practicality, in order to overcome mechanical valve delays and the inertia of the new fuel/air mixture, and to take advantage of the momentum of the exhaust gases, each of the strokes invariably begin and end outside the 0, 180, 360, 540 and 720 (0) degree crank positions

Compression Stroke

The compression stroke begins as the inlet valve closes and the piston is driven upwards in the cylinder bore by the momentum of the crankshaft and flywheel.

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Compression in a spark ignition engine is used to force the oxygen and hydrocarbon molecules of the fuel/air mixture into close proximity with each other. This not only raises the temperature significantly (the work of compression is converted into heat), but the action transforms the mixture from something that is extremely difficult to ignite under normal atmospheric conditions into something that will burn rapidly after being ignited with just a spark. Unfortunately, with lower (unleaded) octane fuels and high compression ratios, it is possible to generate sufficient heat during compression for the mixture to auto-ignite, thereby effectively limiting the practical volumetric efficiency of the Otto cycle

Spark Ignition

Spark ignition is the point at which the spark is generated at the sparking plug and is an essential difference between the Otto and Diesel cycles. It may also be considered as the beginning of the power stroke. It is shown here to illustrate that due to flame propagation delays, spark ignition timing commonly takes place 10 degress before TDC during idle and will advance to some 30 or so degrees under normal running conditions.

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Power Stroke

The power stroke begins as the fuel/air mixture is ignited by the spark. The rapidly burning mixture attempting to expand within the cylinder walls, generates a high pressure which forces the piston down the cylinder bore. The linear motion of the piston is converted into rotary motion through the crankshaft. The rotational energy is imparted as momentum to the flywheel which not only provides power for the end use, but also overcomes the work of compression and mechanical losses incurred in the cycle (valve opening and closing, alternator, fuel pump, water pump, etc.).

Exhaust Stroke

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The exhaust stroke is as critical to the smooth and efficient operation of the engine as that of induction. As the name suggests, it's the stroke during which the gases formed during combustion are ejected from the cylinder. This needs to be as complete a process as possible, as any remaining gases displace an equivalent volume of the new charge of fuel/air mixture and leads to a reduction in the maximum possible power.

Tuned exhaust manifolds help to maintain the momentum of the gas during the stroke to assist in the removal of the exhaust gases. They can also be tuned within the maximum power rev range to create reflections or standing waves at the exhaust port to prevent some of the new fuel/air mixture from disappearing through the exhaust port during valve overlap

Exhaust and Inlet Valve Overlap

Exhaust and inlet valve overlap is the transition between the exhaust and inlet strokes and is a practical necessity for the efficient running of any internal combustion engine. Given the constraints imposed by the operation of

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mechanical valves and the inertia of the air in the inlet manifold, it is necessary to begin opening the inlet valve before the piston reaches Top Dead Centre (TDC) on the exhaust stroke. Likewise, in order to effectively remove all of the combustion gases, the exhaust valve remains open until after TDC. Thus, there is a point in each full cycle when both exhaust and inlet valves are open. The number of degrees over which this occurs and the proportional split across TDC is very much dependent on the engine design and the speed at which it operates.

The Diesel Engine

The diesel internal combustion engine differs from the gasoline powered Otto cycle by using a higher compression of the fuel to ignite the fuel rather than using a spark plug ("compression ignition" rather than "spark ignition").

Air standard diesel engine cycle

In the diesel engine, air is compressed adiabatically with a compression ratio typically between 15 and 20. This compression raises the temperature to the ignition temperature of the fuel mixture which is formed by injecting fuel once the air is compressed.

The ideal air-standard cycle is modeled as a reversible adiabatic compression followed by a constant pressure combustion process, then an adiabatic expansion as a power stroke and an isovolumetric exhaust. A new air charge is taken in at the end of the exhaust, as indicated by the processes a-e-a on the diagram.

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Since the compression and power strokes of this idealized cycle are adiabatic, the efficiency can be calculated from the constant pressure and constant volume processes. The input and output energies and the efficiency can be calculated from the temperatures and specific heats:

It is convenient to express this efficiency in terms of the compression ratio rC = V1/V2 and the expansion ratio rE = V1/V3.

History of Diesel Cycle

Rudolph Diesel

Rudolph Diesel was born in Paris of Bavarian parents in 1858. As a budding mechanical engineer at the Technical University in Munich, he became fascinated by the 2nd law of thermodynamics and the maximum efficiency of a Carnot process and attempted to improve the existing thermal engines of the day on the

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basis of purely theoretical considerations. His first prototype engine was built in 1893, a year after he applied for his initial patent, but it wasn't until the third prototype was built in 1897 that theory was put into practice with the first 'Diesel' engine.

Design of a Diesel Cycle

The General Idea

The Diesel cycle is very similar to the Otto cycle in that both are closed cycles commonly used to model internal combustion engines. The difference between them is that the Diesel cycle is a compression-ignition cycle instead of a spark-ignition cycle like the Otto cycle. Compression-ignition cycles use fuels that begin combustion when they reach a temperature and pressure that occurs naturally at some point during the cycle and, therefore, do not require a separate energy source (e.g. from a spark plug) to burn. Diesel fuels are mixed so as to combust reliably at the proper thermal state so that Diesel cycle engines run well.

(We might note that most fuels will start combustion on their own at some temperature and pressure. But this is often not intended to occur and can result in the fuel combustion occurring too early in the cycle. For instance, when a gasoline engine - ordinarily an Otto cycle device - is run at overly high compression ratios, it can start "dieseling" where the fuel ignites before the spark is generated. It is often difficult to get such an engine to turn off since the usual method of simply depriving it of a spark may not work.

Stages of Diesel Cycles

Diesel Cycles have four stages: compression, combustion, expansion, and cooling.

P-v Diagram

The P-v diagram for a Diesel cycle is shown below.

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Diesel Cycle Operation

The Diesel cycle is the cycle used in the Diesel (compression-ignition) engine. In this cycle the heat is transferred to the working fluid at constant pressure. The process corresponds to the injection and burning of the fuel in the actual engine. The cycle in an internal combustion engine consists of induction, compression, power and exhaust strokes.

Induction Stroke

The induction stroke in a Diesel engine is used to draw in a new volume of charge air into the cylinder. As the power generated in an engine is dependent on the quantity of fuel burnt during combustion and that in turn is determined by the volume of air (oxygen) present, most diesel engines use turbochargers to force air into the cylinder during the induction stroke.

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From a theoretical perspective, each of the strokes in the cycle complete at Top Dead Centre (TDC) or Bottom Dead Centre (BDC), but in practicality, in order to overcome mechanical valve delays and the inertia of the new charge air, and to take advantage of the momentum of the exhaust gases, each of the strokes invariably begin and end outside the 0, 180, 360, 540 and 720 (0) degree crank positions

Compression Stroke

The compression stroke begins as the inlet valve closes and the piston is driven upwards in the cylinder bore by the momentum of the crankshaft and flywheel.

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The purpose of the compression stroke in a Diesel engine is to raise the temperature of the charge air to the point where fuel injected into the cylinder spontaneously ignites. In this cycle, the separation of fuel from the charge air eliminates problems with auto-ignition and therefore allows Diesel engines to operate at much higher compression ratios than those currently in production with the Otto Cycle.

Compression Ignition

Compression ignition takes place when the fuel from the high pressure fuel injector spontaneously ignites in the cylinder.

In the theoretical cycle, fuel is injected at TDC, but as there is a finite time for the fuel to ignite (ignition lag) in practical engines, fuel is injected into the cylinder

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before the piston reaches TDC to ensure that maximum power can be achieved. This is synonymous with automatic spark ignition advance used in Otto cycle engines.

Power Stroke

The power stroke begins as the injected fuel spontaneously ignites with the air in the cylinder. As the rapidly burning mixture attempts to expand within the cylinder walls, it generates a high pressure which forces the piston down the cylinder bore. The linear motion of the piston is converted into rotary motion through the crankshaft. The rotational energy is imparted as momentum to the flywheel which not only provides power for the end use, but also overcomes the work of compression and mechanical losses incurred in the cycle (valve opening and closing, alternator, fuel injector pump, water pump, etc.).

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Exhaust Stroke

The exhaust stroke is as critical to the smooth and efficient operation of the engine as that of induction. As the name suggests, it's the stroke during which the gases formed during combustion are ejected from the cylinder. This needs to be as complete a process as possible, as any remaining gases displace an equivalent volume of the new charge air and leads to a reduction in the maximum possible power.

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Exhaust and Inlet Valve Overlap

Exhaust and inlet valve overlap is the transition between the exhaust and inlet strokes and is a practical necessity for the efficient running of any internal combustion engine. Given the constraints imposed by the operation of mechanical valves and the inertia of the air in the inlet manifold, it is necessary to begin opening the inlet valve before the piston reaches Top Dead Centre (TDC) on the exhaust stroke. Likewise, in order to effectively remove all of the combustion gases, the exhaust valve remains open until after TDC. Thus, there is a point in each full cycle when both exhaust and inlet valves are open. The number of degrees over which this occurs and the proportional split across TDC is very much dependent on the engine design and the speed at which it operates.

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otto cycle vs diesel cycle

In this article we will focus on peak pressure, peak temperature and heat rejection. The P-V and T-S diagrams of these three cycles for such a situation are drawn simultaneously as described below.

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In the above diagrams the following are the cycles

Otto cycle: 1 – 2 – 3 – 4 – 1 Dual cycle: 1 – 2’ – 3’ – 3 – 4 – 1 Diesel cycle: 1 – 2” – 3 – 4 – 1

Remember that we are assuming the same peak pressure denoted by Pmax on the P-V diagram. And from the T-S diagram we know that T3 is the highest of the peak temperature which is again same for all three cycles under consideration.

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Heat rejection given by the area under 4 – 1 – 5 – 6 in the T-S diagram is also same for each case.

In this case the compression ratio is different for each cycle and can be found by dividing V1 with the respective V2 volumes of each cycle from the P-V diagram. The heat supplied or added in each cycle is given by the areas as follows from the T-S diagram

Otto cycle: Area under 2 – 3 – 6 – 5 say q1 Dual cycle: Area under 2’ – 2’ – 3 – 6 - 5 say q2 Diesel cycle: Area under 2” – 3 – 6 – 5 say q3

It can also be seen from the same diagram that q3>q2>q1

We know that thermal efficiency is given by 1 – heat rejected/heat supplied

Since heat rejected is same and we know the order of magnitude of heat supplied, we can combine this information to conclude that

Thermal efficiency of these engines under given circumstances is of the following order

Diesel>Dual>Otto

Hence in this case it is the diesel cycle which shows greater thermal efficiency.

Difference Of Otto And Diesel cycle

Engine basics

Mister Rudolph Diesel was aware of the gasoline engine (Otto cycle) problems and wanted to improve it. The gasoline engine inherently has problems with efficiency and/or fuel. In order to improve the efficiency one must increase the compression ratio of an internal-combustion engine (see the bonus section at

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bottom of this article). However, in the gasoline engine there is a limit – the gasoline-air mixture will self ignite once the compression gets too high (because every compression drives temperature increase). So, either you can have a low-efficient, low-compression engine that uses a cheap fuel, or you can have a high-efficient, high-compression engine that uses expensive, high-refined fuel that wont self-ignite even at high compression levels (a 120 octane gasoline?).

In diesel engine this problem is solved. The diesel engine can use much higher compression levels than the gasoline engine reaching higher efficiency. In addition, the diesel engine can use fuel that is not nearly as refined as the high-octane gasoline fuel (thus cheaper).

To make this possible, Rudolph changed the Otto cycle and created the diesel cycle. The difference is that during compression phase, no fuel is present in the cylinder and thus no self-ignition can happen. The fuel is only injected at the moment the ignition is wanted – when injected into the hot pressurized air the diesel fuel self-ignites immediately (the diesel-air mixture, as we said already, is happy to ignite even at relatively low temperatures).

The diesel fuel is better for a diesel motor because it self-ignites more readily, and this is desirable in the diesel cycle. If we try to inject gasoline instead of diesel into the diesel engine, this may not work because gasoline, having much higher self-ignition temperature, may not ignite at all. Of course, if we build the diesel engine to have a really, really high compression ratio then even the 120 octane gasoline will self-ignite and our engine will be able to work with almost anything we put in our tank.

(However, remember that the diesel fuel is better in lubricating things than the gasoline, and diesel-engine manufacturers use this property heavily – so using even low-octane gasoline in your diesel engine may fail because fuel supplying parts will not be lubricated enough. Don’t kill your engine!)

How about using diesel in a gasoline engine? Maybe it would be possible to build an Otto-cycle engine that runs on diesel fuel, but it would have to have very low compression ratio to avoid diesel-air mixture self ignition problems. In turn, such an engine would have very poor efficiency (the efficiency is directly connected to the compression ratio). There is additional problem with diesel – it doesn’t vaporize so readily as the gasoline and because of it, such an engine would have

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to use complicated system of high-pressure injection nozzles to generate rich-enough fuel-air mixtures (as in the diesel engine).

Yes, the diesel engine has benefits (high efficiency, lower fuel restrictions), but it is much more complicated to build than the gasoline engine. The gasoline engine has spark plugs to ignite gasoline-air mixture while the diesel engine needs to have complicated system of high pressure injection nozzles that need to inject controlled amount of fine fuel mist into the cylinder at exactly right moment – a quite difficult job (luckily, the diesel fuel is quite lubricating and non-abrasive so it is not an impossible job.)

The diesel engine is much heavier than the gasoline engine – this is because the higher compression ratio produces higher stress on materials. In the diesel engine you will find thick cylinders, heavy pistons, rods and valves. All this moving mass restricts the speed a diesel engine can turn. A typical car diesel engine doesn’t turn faster than 4000rpm, while a gasoline engine goes up to 7000rpm. (Also notice that the diesel fuel vaporizes quite slowly and, at high speed, there won't be enough time for all the fuel to burn out, thus diesel engine efficiency will be reduced.)

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Controlling power

There is one profound difference between diesel and gasoline engine. This is about the amount of air that comes into the cylinder during the first phase of the cycle (intake).

In the gasoline engine, there is a special valve (throttle) that restricts the amount of air-fuel mixture that is filled into the cylinder. When the engine is idling, only a limited amount of air-fuel mixture is allowed in. At full power, the valve is fully opened allowing the cylinder to suck the maximum amount of the air-fuel mixture in. It means that the final pressure level at the end of compression stroke highly varies depending on how much air-fuel mixture was allowed into cylinder during the intake stroke.

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Also, note that the concentration of the fuel in the air-fuel mixture is always the same, no mater what is the power level of the engine. Thus, the mixture is always aimed at full combustion (or more or less so – read further about it). The concentration of fuel in this mixture is, of course, always high enough to make self-sustained burning.

The diesel engine is another story. Here, the amount of air sucked into the cylinder is always the same, invariable of the power level. However the power is controlled by the amount of the fuel that is injected into the cylinder. The good thing is that the final pressure of the air (just before the fuel is injected) is always the same and so the injected fuel will find nice temperature to burn even if the engine is running at low power level. (Even if a very small amount of fuel is injected – smaller than otherwise needed for self-sustained burning – it will all burn out because the surrounding air temperature is high enough).

Now we know how power is controlled in both engines. So what can we do if we want to get more power?

We can improve efficiency. This is the greenest way. But that is for ladies. What we want is creating a monster.

The only other way is to burn more fuel in the same amount of time. The fuel is where the power comes from and if we want power we have to burn it – burn it fast. However, not only that we have to increase supply of fuel, but we also have to increase supply of air. Supply of air is the major problem (the air is bulky) and there are several ways to do it.

The first one is to make larger cylinders or to increase number of cylinders. So, in each cycle more air will come in, and we will be able to burn more fuel producing more power in each engine cycle. This approach works well for both, diesel and gasoline engines.

Second, we can put more air into the cylinder than it is cylinder’s volume – we simply force it inside by turbo-charging or super-charging. If we force two liters of air into one litter cylinder we could get twice the power in each stroke. But of course, as we already started with pressurized air, at the end of the compression stroke we will end up at much higher pressure-level than in non-force-charged engine. In the gasoline engine this will cause premature self-ignition of the air-fuel

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mixture and our engine will break down (except if we use a high-octane fuel that won’t self-ignite). The diesel engine, however, doesn’t have this problem. That is why turbo-charging or super-charging is more popular way for boosting power on diesel engines than in gasoline engines. (In addition, the diesel engine is by its nature built more robustly than gasoline so increased pressure won’t generate major problems to materials.)

Third way for getting more power would be to make the engine turn faster. Although the same amount of fuel will be burnt in each cycle, the number of cycles in unit of time will increase and thus we get more power. Unfortunately, diesel engines are very limited because of its heavy high-pressure-proof design. Increasing turning speed of a diesel engine would break the engine apart (except if you use stronger, more expensive materials – but there are not many things better than steel). However, the gasoline engine is much lighter – every shaft, cam or rod inside a gasoline engine is light and can move very fast without self-breaking. Thus increasing turning speed is the preferred method of gaining power in the gasoline engine.

Compare otto cycle with Diesel cycle?

These two cycles can be compared on the basis of either the same compression ratio or the same maximum pressure and temperature.

1 - 2 - 3 - 5 = Otto Cycle,for the same heat rejection Q2 the higher the

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1 - 2 -4 - 5 = Diesel Cycles, heat given Q1,the higher is the cycle efficiency.

So from T-S diagram for cycle 1 - 2 - 3 - 5, Q1 is more than that for 1 - 2 - 7 - 5 (area under the curve represents Q,).

Hence Otto > η Diesel

For the same heat rejection by both otto and diesel cycles.

Again both can be compared on the basis of same maximum pressure and temperature.

1 - 2 – 3 – 4 = Otto Cycle; Here area under the curve 1 - 2' - 3 - 4 = Diesel Cycle 1 - 2'- 3 - 4 is more than 1 - 2 – 3 – 4So ηdiese l > ηotto; for the same Tmax and Pmax

Conclution:-

It’s a predict feels highghly oblisised that I am try to complete my term paper about the topic Otto Cycle Vs Diesel Cycle,its my glad to do this term paper with the help of internet and some books and somes pdf files.i hope that I have done my best hard work to do this work hard to hardest to achieve my goal.And thanx to my sir that he has given to me this work to better myself

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Refferences

Links

1. www.scribd.com/.../8-Comparison-of-Otto-Diesel-Dual-Cycles2. www.brighthub.com. Marine Diesel Engines3. happytreeflash.com/otto-and-diesel-cycle-ppt.html4. http://www.transtutors.com/university-Columbia/system-response-

analysis/compare-otto-diesel-cycle-tp-6.htm

Books

1. Basic and Applied Thermodynamics: Nag, P K: PB Books

2. Thermodynamics: By Enrico Fermi - Enrico Fermi - 1956