Advancement In Internal Combustion Engines With Turbochargers

1)Initiate, define, plan, manage and execute a major project, demonstrating a critical awareness of professional standards, relevant codes of conduct, sustainability and safe systems of work.

2)Critically evaluate arguments, assumptions, abstract concepts and data in the area of a specific engineering problem and apply specialist technical knowledge, understanding and analytical and synthesis skills, in developing a solution to the problem.

3)Communicate all aspects of the project in a logical and effective manner to a technical audience.

History and Development of Turbochargers

At all times, there is a continuous work on the improvement of Internal Combustion Engines (ICEs). The automakers work on its improvement to provide a dependable and robust service, which benefits the economy of fuel, besides the shelf life of the engine. Despite the availability of various alternatives for fuel in the vehicle market like, compressed natural gas, propane autogas and pure battery-electric, the reliability and efficiency of ICE is valued a lot.

The use of gas turbine engines came in to picture in the previous era. Whereas, the pump and the centrifugal compressor were the main fundamental turbomachine which had vast applications in various filed like in swimming pool pumps, washing machines in houses, refrigeration equipment, piston engine turbochargers, gas pipeline pumping compressors, and in gas turbines engines. However, before Second World War there were less known applications of centrifugal compressor. But, due to its capability of producing greater thrust when compared to the pistons that are driven by the internal combustion engines, its benefiting values paved new way for the aviation field. It helped the aircrafts to have high speed, gave high altitude for the aircrafts, piston engines that are supercharged and turbocharged, etc. Thus, the wide range of use in the aviation allowed to increase the number of research and development. The automotive turbocharger was developed based on the gas turbine engine, for more potential. This engine can be used for additional experiments and is considered safe, because it has low power output, it is cost effective, it is easily available and it involves easy construction. On the other hand, the automotive turbocharger makes pre-packaged system of turbine and compressor available. For an ideal educational demonstration, enlarged and open layout of the engine and its components are considered as better option. 

The disadvantages of the old turbocharger are the problems that are overcome by the advanced turbocharges. Thus, identifying the suitable charger is the main problem in this project.

The combinations of compressor and turbine’s performances include problems to design the turbocharger. In order to make the turbocharger’s design, at least the following characteristics must be considered:

• Environmental performance
• Cost of the design
• Vehicle performance

The major step to design the turbocharger, must quantify the above characteristics. To achieve these characteristics for several technology applied in a specific design. Particularly, the relationship between the performance and the element cost. On the other hand, probably the heavy vehicles also need more support from the body frame. Various technologies break down to the following questions that are listed below:

• If or when the heavy weighting is required?
• Why heavy weight is required by the specific performance targets?
• How much heavy weight is required to achieve the required fuel consumption?
• What is the impact of heavy weighting?
• What are the cost of heavyweight material?
• What is the environmental performance of the heavy weight material?

Benefits of Turbochargers

Therefore, the turbocharger must establish the efficiency, power and specifications specified for the turbocharger. 

The objectives of this project are as follows- The working principle of turbocharger will be studied. The working principle of GT engine will also be studied, where all its components will be discussed. The connection with the turbocharger will also be investigated. The compressor map analysis will be provided. The efficiency, mass flow rate, boost pressure capabilities and turbo speed will be researched. The CAD design to represent the project’s working will be disclosed. Advancement in the internal combustion engines will be reviewed. The specifications and design of the project will be identified. The engineering design work, design problems, project resources, relevant theory, development process and limitations will be determined. Effective solution for the problem will be identified and convincing validation will be specified. The test plan will be delivered. Finally, the necessary results will be analyzed. The outcome’s objective appraisals will be determined. Project’s overall success will be imparted with the evidenced deliverables. The report will be concluded with appropriate recommendations. 

According to the authors (Muqeem & Kumar, 2013), turbo chargers are mostly used in automotive industry to enhance the IC engines. It increases the potential of powerful internal combustion engine. It also provides feasible solutions for manufacturing vehicles. Hence, these turbo engines are more popular in the automobile industry. This turbo charger is mainly used to produce more power from the engine. The turbo charged engine is more powerful than the normal engines, because the turbine forces the engine to intake more air fuel into the combustion chamber. Its main purpose is to increase the efficiency of the combustion chamber. Different technologies are used to assist the turbo charging IC engine, which improves its volumetric efficiency. Inter cooling is one of the technology in which the charged air is cooled before it moves in to the chamber. Hence, it increases the mass flow rate. Twin charging is also one of the technology in which the engine is boosted through the super charger and then it is boosted by the turbocharger. Some other technologies are also used to increase the volumetric efficiency. Turbo chargers work based on the forced induction system, where it compresses the air which is moves into the engine. The main advantage of this compression system is that, the engine will squeeze more air into the cylinder and more fuel will be added. Thus, each cylinder will produce more power from its explosion. These turbo charged engines produce more power than the natural engines. To spin the turbine, this charger uses exhaust flow of the engine and it spins the air pump.  

Challenges and Considerations for Turbocharger Design

In this research paper, the authors (Shaaban & Seume, 2012) state that, the thermodynamics properties of the working fluid in engine is affected by the performance of the turbocharger. Hence, it also affects the performance of the engine and it leads to heat transfer during the operations of the turbocharger and this heat affects the turbine’s power production. Thus, the compressor and volumetric efficiency of the engine consumes the power. This non adiabatic performance of the engine limits the charging process and reduces the performance of the engine. In this paper the authors mainly investigate the effects of turbocharger in the engine’s charging process. Here, turbocharges of the two passenger car is experimentally and theoretically investigated. It also explores the impacts of turbine casing insulation. This investigation reveals that the thermal energy can be transferred to the compressor in all conditions. When it has high rotational speed, the thermal energy is transferred first to the compressor and then to the other parts. Hence, at the high rotational speed, the compressor remains adiabatic due to the heat transfer process inside the compressor. In the part where load operation taking place in the turbocharger, the non-adiabatic performance and tangible effect is identified. The most affected parameter is turbine power and then volumetric efficiency of the engine. To reduce the turbo lag and turbine size, turbine insulation is recommended. The actual power of the turbine is decreased by 55% at 6000 rpm power due to the transfer of thermal energy from turbine. The effect of thermal energy transfer can be decreased by increasing the rotational speed of the turbine with constant temperature.

As per the authors (Ghodke & Suryawansh, 2012) in the next few years, the reduction of CO₂ emission will be a demand in the vehicles, for comfort driving and it would become a challenging task for the automobile industry. The main approach for this problem is displacement of combustion engine during its maintenance. This method is called as downsizing. It requires turbocharging to improve performance and torque. A simple charging unit is not enough to improve the performance and it requires complex charging systems for stringent emissions. Here, the goals are developed with thermodynamics and the operations of passenger car will increase the engine power with high torque at low speed and improve the driving response in different conditions like elasticity response and start up response. The consumption of primary energy during testing will be reduced. The observation of the exhaust gas will lead to drastic reduction in the emission level. The future goals will be achieved by using the small displacement engines. The engines which have low displacement provides many advantages in emissions and fuel consumptions. But, its torque level is comparatively low than the large displacement engines. The advantages of turbocharger technology is summarized by the authors to fulfil the demands of the low emission with high performance passenger vehicle.

Technologies for Improving Turbocharger Performance

It is stated by the author (Muqeem, 2012) that, the main objective of the turbocharger is to improve the volumetric efficiency of the engine. It is achieved by increasing the intake gas density. The temperature and pressure of the engine is increased when the amount of intake air is increased. The turbocharger has intercooling system which is used to cool the intake air. Here, the main goal of the author is to improve the intake air temperature and to make it equivalent to the ambient temperature. To increase the inter-cooling of the intake air, a specially designed intercooler is used in which the air acts as a hot fluid and cooling coil of the intercooler which is fitted in the dashboard acts as a cold fluid. In the cooling process, the intake air flows between the fins of the inter cooler and the evaporator releases the refrigerant. Thus, the author concludes that, the mass of oxygen which is fed into the engine is 1.43 times the normal intercooler and it is 2.618 times the refrigerated inter cooler. Hence, by increasing the amount of oxygen the burning rate will be increased and it will control the emission level. The amount of oxygen added in the combustion air increases the potential of the burning diesel engine.

The researchers in (Mitianiec & Rodak, 2011) analyzed the main problems of charged spark ignition engine which is controlled by the air fuel ratio. This air fuel ratio is changed with different pressure levels to get high torque with some specific fuel consumption and gas emission level. This charging engine has issues in the medium and it loads high value for the low speed engines. It leads to knocking and abnormal combustion process at high boost pressure. To prevent the knock, boost pressure control algorithm is described by the authors. Hence, the engine can work within the knock boundary. For the experimental test, the author used medium capacity Toyota Yaris 1300 SI engine. This engine is equipped with a turbocharger which has VTG. This turbo engine can control the turbine’s mass flow rate by using waste gate system. This approach enables the engine to charge at different loads and at rotational speeds. A special computer program is used in the Lab to analyze the signal level of knock and regulates the waste gate and VTG system in the opening. A high voltage knock signal is passed into the ECU and it is transformed with the FFT procedure. It provided the knock signal at the rage of 2000-8000 Hz. A control signal of knock is obtained in the range of 0 to 0.01 V which is transferred to the control unit to regulate the mass flow rate of the gas which is exhausted by the waste gate and VGT system. The output signal produced by the FFT is higher than 0.01 V. Hence, the waste gate valve is opened to reduce the mass flow rate of the gas which is emitted by the turbine. It also reduces the turbo charger rotational speed and compressor ratio.

Inter-cooling and Volumetric Efficiency

According to the researcher (Uzun, 2010), thermal efficiency and fuel economy is more important for the engine. The efficiency of the engine is increased by cooling the air through intercooler system. Mostly the researches related to the engineering problems deal with the experimental researches. These researches consume more time and it is expensive. In the last few years, neural networks are used in most of the engineering applications. Thus, the author concludes that the neural networks are robust and secure method to overcome the issues of intercooling in turbocharged engines with specific fuel consumption. Neural Network model is developed by the author and is tested in the MATLAB environment. This study analyzed the specific fuel consumption engines with and without intercooling systems. This statistical analysis reveals the performance of neural network model. The outputs of this model are compared with the experimental results and it shows that this neural network model is highly successful and it determines the performance effects of the intercooling system in a diesel engine. The overall result of the research suggests that neural network model can be used as an alternative method to estimate the performance effects of the intercooling system in a turbocharged diesel engine.

As per (Canli, Darici & Ozgoren, 2010), it is concluded that the automotive applications has some main problems in its effect, comfort and cost. Thus, it requires internal combustion engines with high specific power and it should have less emissions. To overcome these issues, light and medium size engines that are considered are turbocharged, because it avoids the internal combustion engine’s effects. The authors studied to improve the performance of the internal combustion engine. The studies also include supercharging system. But, the main problem in supercharging system is that, the air density is decreased during the air compression. Also the high temperature air leads to pre-ignition in the spark ignited engines. Different types of methods are developed to cool down the heated air in the supercharging process. Compact heat exchanger (intercooler) is used for one of the method to cool down the charging air. The main purpose of this intercooler is to cool down the air which is heated in the turbocharging process. The air becomes denser, when it is cooled and it has better combustion to generate more power. This denser air also reduces the knock. This inter cooling process is used to increase the performance of the vehicle and this process is added in the supercharging system of petrol and diesel engines. Pressure drops, revolution of engine and air density are the main input parameters for the calculation of the power output generated by the engine. From this analysis, it is found that the output of the engine power has increased 154% by using the intercooler.

Compressor Map Analysis

According to the authors (Kusztelan, Wang, Marchant & Yao, 2011), one dimensional analysis with AVL boost software is used for the compression of spark ignition engines, which utilizes the turbocharger fitted by the manufacturer and has modified twin entry to adopt the inlet ports of the two turbines. Reconstruction model is used in the AVL boost which considers the accurate parameters of the physical engine. The variations in the model is made by the manufacturer with single entry turbocharger to predict maximum torque and engine power. It is also compared with the manufacturer’s data and calculations. This study also concentrates on the comparison of engine performance with single and twin entry turbochargers. It analyzed the speed of the shaft, torque and efficiency of the compressor with low engine speed of 1000 to 3000 RPM. It increased the average response of the engine and it is increased as 27.65%, 5.5% and 5.5% in shaft speed, power of the engine and torque. Hence, it improved the drivability of the vehicle. This study reveals the benefits of turbocharger with twin entry.

From this literature review, it is concluded that, various attempts are made to increase the output power of the engine and to reduce the emission of the engine some changes are implemented with additional accessories such as, intercooler with turbocharging technology. This technology can be used in future to produce the engines with more power and low emission, which is possible with the advanced turbocharging technologies. Also conventional turbocharger can be used to enhance the power which is generated by the engine and the wasted power will be used by the engine without any upgradation of the turbocharger. This turbo charger will enhance the engine’s performance and this technology will save more money. The same amount of energy generated by the complex engines will be generated with low capacity engines and it will reduce the production cost. Thus, we can produce lighter vehicles with high performance engines, low fuel consumption and emission.

The development of turbocharger will be investigated. The compressors, turbochargers, Small GT Engine are the areas to be researched. Further, it is significant to understand the performance and the characteristics of the turbocharge for the success of this project, thus these factors must also be researched in this dissertation.

Chapter 1 is the introduction part for the whole project. It signifies the importance of the turbochargers and it was motivated towards its advancement. This chapter also contains Literature Review. This section contains reviews of various researchers that enlighten with additional information about the topics to be discussed in this dissertation.

Thermodynamics and Exhaust Gas Analysis

Chapter 2 briefly sketches the background for the literature Review presented in the dissertation. This chapter acts as a base for this project, to understand the concepts involved in the project.

Chapter 3 furnishes details about the required data for the project, with data analysis. The other areas covered in this chapter includes- Turbocharger Efficiency, Turbo charging system efficiency, Indicated Engine Power, Increasing the piston displacement, Increasing the density of the charge and engine's mechanical friction.

Chapter 4 provides in depth information of the specifications and design of the project. This chapter delivers the engineering design work, design problems, application of relevant theory with justification, development process, project resources and limitations.

Chapter 5 comprises of solution and validation part. This chapter brings the effective solution and convincing validations for the project. It is provided with a test plan to determine the solution.

Chapter 6 is assigned for results section, where the output is analyzed. Further, this chapter concludes with objective appraisal of outcomes and overall success of the project.

Chapter 7 shows the met objectives and the evidences of the deliverables, to believe that the project has accomplished the desired objectives. The working principle of turbocharger and GT engine are understood. All the components are studied. The compressor map analysis is provided. The efficiency, air flow rate, boost pressure capabilities and turbo speed are researched. The CAD design to represent the project’s working is disclosed.

The last part of this dissertation entitled as Chapter 8, which includes conclusion for this project. All the areas covered are discussed in this chapter to express the purpose of this project.  

The growth of small turbocharger which contains single stage centrifugal compressor and a single stage radial inflow turbine are present since 400 years. The time duration lead to the demand for improvement. The demands were mainly to fulfill the economic constrains and thermodynamic advancement.

Besides maximizing the efficiency, the turbocharger also helps in amplifying the engine’s output power, by allowing additional air in the combustion chamber. Right from 1920’s, turbocharger are known for its efficiency. It was Alfred Buchi, a scientist who found the idea of utilizing the waste energy that comes from the engine’s exhaust. Buchi had attempted to explain the very first prototype earlier in 1915, but it turned out to be a disaster. Only after a lot of struggle he was able to prove the prototype in 1920. He used turbocharger which maximizes the power ranging till 40 percent, to accomplish his research.  

Boost Pressure Control Algorithm

The aircrafts, ships, trains, electrical generators and so on mainly utilize the Gas Turbine engines. Such engines are internal combustion engines, which requires air identical to fluid, for working. It contains rotating compressor that is fixed to the downstream turbine, along with an ignition chamber generally known as combustor that is present at the center. The fuel’s chemical energy is taken and converted as a mechanical energy, air for deriving the shaft.

The purpose of developing the turbo-based Gas Turbine engine is increase the output when compared to the small engines, then it aims to increase the speed and provide better handling. The other reason to use the turbo-based GT engine is that, the engine’s power is controlled by the air based on fuel ratio. The turbocharger’s weight issue can be resolved small engine, which has more power better handling. 

In terms of aerodynamic, compressor/ single stage centrifugal compressor is the vital part of gas turbine and small turbocharger ("Compressors", 2018). There are conflicts when it comes to efficiency, shelf life, flow range, inertia, design cost and development of test. The two factors that dominate the selection of the compressor for the automobile turbocharger applications include, less cost and less inertia. 

The use of turbo charger for any kind of engine has the capacity to save huge amount. Today the fact is that all the automotive firms are concentrating on light engine which has the capacity to generate high power. However, turbo charged engine sounds economical. 

The design phase of this project concentrates on layout’s configuration plan and budget. The compressor and turbine wheels are designed and configured. Optimization of the wheel’s strength is carried out and calculating the durability. 

This chapter emphasizes on the background of the project. The background research benefits the literature review in the previous chapter, of this dissertation. The evolution of Turbocharger is presented and then the small GT Engine is discussed. Finally, the design phase of the project is furnished in this chapter. It is observed that turbo charger can help in saving more cost and they are economical. 

This chapter is entitled as Data Analysis, which supplies different types of significant data for the project. The sections that are discussed in this chapter includes- Turbocharger efficiency, turbo charging system’s efficiency, air flow rate, indicated engine power, increasing the piston displacement, increasing the density of the charge and engine's mechanical friction. 

The turbocharger GT engine operation has three types. They are Turbine-Driven compressor, propelled by engine exhaust gas and, increase in air flow and density. The turbocharging benefits with increased fuel efficiency, reduced emissions and enhanced engine performances. Turbocharging is the main operation of optimized air flow, density and reduced emissions (Bozza & De Bellis, 2011). 

Experimental Testing and Results

Turbo Speed

τ available=(1+FA)ecetemT3T1

τ required=(CpcCpt)(Kpc0.286-11-pnu)

τ available - Characteristic value available

τ required - Characteristic value required

U= (k,-1k,)

et  - Turbine efficiency decimal

em - Turbocharger mechanical efficiency decimal

Cpc - Constant pressure specific heat of ambient air KJ/Kg.k

Cpt - Constant-pressure specific heat of heated air, KJ/Kg.k

All the characteristic values depend upon turbocharger’s efficiency and temperature ratio across the engine (De Bellis, Marelli, Bozza & Capobianco, 2014). 

Efficiency

The turbocharging process of efficiency is defined using the following two ways, as given below:

1. The isentropic compression of the working medium from initial state to final state (the initial state indicates 1^ststate and the final state indicates 2^nd state).
2. The isentropic expansion of the exhaust gas from an initial state to final state (the initial state indicates 3^rdstate and the final state indicates 4^th state).

All the states are indicated as generic state, from the start till the end of expansion process and compression process.

The formula for calculation efficiency is given below: 

If the flow is pulsating, then the energy flow should be integrated over the cycle. The mean flow rate of and the mean temperature of   derived from the enthalpy conservation in the flow and the equivalent pressure peq.

Fulfilling the constant value s and preferably the ambient pressure.

The general definition of efficiency for the turbocharging process is given below.  

Turbo Charging System Efficiency 

Network output WNet= work done by piston + Gas exchange work

                                  =Area A +area

Area A=P1V1γ-1(rp-1) *(rγ-1)

Area B= work done by turbocharger 

wnet =Work done per unit of air mass  

p0= atmospheric pressure

p1=pressure after compression

T0=atmospheric air temperature

V1=volume of boosted air

rp=pressure ratio

r=compression ratio

cp=Specific heat of air

= turbocharger efficiency

Air Flow Rate

The engine’s produced output is the amount of air that depends upon the inducted per unit time. The output’s degree of utilization is the air and thermal efficiency of the engine (Ekici, Sohret, Coban, Altuntas & Karakoc, 2016). 

The air flow rate has three possible methods that are utilized for increasing the consumption of engine, these are (1) Increasing the piston displacement (2) Running the engine at higher speeds (3) Increasing the density of the charge 

The piston displacement is using for increase the weight and size of the engine. It is used for additional cooling.

Running the Engine at High Speeds

The engine’s mechanical friction losses and imposes greater inertia stress the parts of engine i.e., due to increased speed.

Increasing Density of the Charge

The density is allowing a greater mass of the charge to be inducted at same volume. 

Air Delivery Ratio

m_at=0.03D_eN_ep_a  

A turbocharger air delivery ratio

=

Turbo charger pressure ratio is defined as 

Pressure ratio across the compressor

Future Directions in Turbocharger Technology

      = 1 +

The temperature ratio across the compressor 

Compressor efficiency decimal 

Extant Power of Final Result

Power and Torque

The torque’s maximum power is approximated at 570 rev/min. The torque rise percentage was 18.9%. There was increase of 21.6% after servicing and it reached 33% after turbocharging. There was increase ranging from 63.1KW to 65.9KW, at 570rev/min and it remained as the highest output power working range for the engine’s speed. Additional increase in the air pressure of local atmospheric pressure (that is boost) results in producing more power. The engine burns air and fuel ration at 14.7:1; if you burn more air the fuel should burn more. Using particularly high altitudes utilizing less oxygen has thinner air and reduces power around 3% per, at 1000 feet above.

The engine working is under load for 10-15 min to compare the normal operating. The result of fuel pump is calibrated to provide 51 mm3; using fuel rating speed by full load the injection pressure is 210 bars (Kong & Lim, 2011).

The compressor calculates by theoretical temperature rise. The theoretical value of power is always less than 1.0 (theoretical value using the temperature rise across the compressor/actual temperature rise).

 Turbine Efficiency of Power

The turbine efficiency of power is less than 1.0.  Calculation is done based on the condition (actual temperature drop across the turbine/the theoretical temperature drop). 

The turbocharger have different types of requirements as its resources. Some of them are efficiency characteristics, height and width of the map and rotor’s moment of inertia. The new compressor and the type of turbines are constantly developed for various engine applications. Various regional legal emission based rules directs to diverse technical solutions.

In turbocharger the operational characteristics are influenced by the compressor and the turbine. The compressor and turbine wheels are designed with the help of computer program that contains 3D (three dimensional) calculations for the exhaust gas flow and air. The wheels calculation are optimised by finite element method (FEM). Even the durability is evaluated. 

This chapter successfully delivers the required information about Turbocharger efficiency, turbo charging system’s efficiency, GT engine, air flow rate, indicated engine power, increasing the piston displacement, increasing the density of the charge and engine's mechanical friction. The CAD modelling of turbocharger is shown. The data analysis results are determined. 

OEM Nr.:	55232607.01E
OES Nr.:	49373-03003
Brand:	FIAT
Engine type:	SGE 875cc
Displacement:	0.88
Power output:	63
Fuel:	G
Turbo specifications:	TD02H2
Turbo info:	W/G
Cartridge:	49373-08110
Cooling:	Water cooled
Manifold:	Y

This chapter gives a clear view of the necessary specifications and design that are required for the project. This chapter tends to successfully help the readers know about the design and its specifications, with the help of engineering design work and development process. The limitations and the design problems will be discussed in this chapter. The resources required for the project will be listed. The relevant theory to be applied will be highlighted, for which an apt justification will be described.

Conclusion

On the whole, turbocharger is a combination of compressor and turbine. These both combinations have mounted on a common shaft. The exhaust gases from the turbocharger is used to rotate the turbine which in turn moves the compressor.

The commonly used two types of compressors in turbocharger are:

• Axial flow compressor and
• Centrifugal compressor 

The Axial flow compressors are most efficient with engines using heavy oils. The applications of larger radial units where internal modifications might be needed.

The Centrifugal compressors are generally used in small size of turbocharger for e.g., turbocharger in automotive system.

There are three main parts of a turbocharger:

1. Central Hub
2. Turbine

• Impeller / Compressor 

The turbine and compressor wheels are contained in their own conical housing. The amount of air depends on the size of these wheels. The central hub contains shaft. The central hub with the help of bearings, then it connects the turbine and impeller wheel on the opposite sides. The hub produces extreme heat due to high speed of rotations. The water cooling or any other form of cooling systems prevents temperature from rising. The mixing of gases are prevented by the compressor and turbine. A filter is used to ensure that the air going to the compressor side is free of any impurities (Srivastava, 2018). 

The turbine side is made up of cast iron material. The nozzle blade ring of turbine is used for two purposes, as follows:

1. To guide the incoming gas into the turbine wheel.
2. To house the turbine bearings.
3. The outlet side of the turbine casing consists of blower and air passages to supply air to labyrinths seals.

The compressor side is made up of aluminum alloys. The compressor consists of main parts like inlet part, inducer, diffuser and outlet casing. The inlet part deals with the drawing air from the surroundings. The usage of drawing air from the engine space, is a complex ducting arrangements. While the benefits of the drawing from the engine doesn’t require for long and complicated ducting. The advantage of drawing air from the deck spaces have low air temperature and humidity.

The below map indicates the relationship between the pressure ratio and volume. The centrifugal compressor is limited by the surge and choke lines of the map.

The surge line is located in the left side of the map’s width. The small volume flow and too high pressure ratio, the flow can adhere for a long time to the blades. Such a flow in the fixes frequency and resultant noise is known as “surging”.

The turbocharger turbine consists of wheel and turbine housing. It converts the exhaust gas into mechanical energy to operate the compressor. The exhaust gas is restricted by the flow cross-sectional area. The results operate in the pressure and temperature drop between the inlet and outlet. The operated drop is converted into kinetic energy, to drive the turbine wheel (Bajpai & Chandrasekhar, 2017).

The turbocharger turbines have two main types namely, axial and radial flow turbine. The axial direction turbine flow through the wheel is the only axial direction. The radial flow turbine is directed from the outside, in the axial direction.

The performance of the turbine increases the pressure drop between the inlet and outlet increases.

The turbine is classified into two stages. Single stage and may be axial, mixed flow or radial.

The radial turbines may be nozzle or nozzle less. Nozzles are used on larger turbines. Nozzle less turbines reduce the size and cost.

The turbines spends little time during the exhaust pulse cycle.

Mixed Flow, Forward Swept Turbine Characteristics 

Technology options for efficient wide range of compressor.

Requirements

1. To deliver the required boost pressure.
2. Efficiency
3. Reliability and guaranteed service for life time.
4. Wide range to work form engine to maximum speed. 

Oil is required at the correct flow rate and pressure to do the following:

1. Stabilise the rotating shaft and journal bearings.
2. Act as a coolant before high turbocharger speed is reached.
3. Lubricate the thrust and journal bearings. 

Operate the engines, the oil filters will remove any foreign matter before the oil reaches the turbocharger bearings. It can be a very costly mistake.

All of these materials can cause damage to the bearings when the amount is sufficient to cause bearing wear and bearing-housing bore wear. 

Diesel lubrication is a highly important part of the engine, although modern oil technology has gone a long way in providing good oils.

• Oil Deterioration:The high temperatures that are present in modern diesel engines can cause oils to crack or break-down.
• Outside Contamination:Usually caused by its exposure to heat and air. 

Any material, which enters into the systems is without doubt, going to damage the turbocharger. It damages the engine.

This type of material will vary the air system to engine valve fragments in the exhaust system. The turbo will react with possible black smoke, loss of power, excessive oil usage and leakage and damaged wheels (A. Savin, A. Pivovarov, J. Radin & V. Slivinskiy, 2013). 

In material and workmanship problems occurs only quality assured materials are used and constant quality checks to meet the stringent OE specifications.

Application of relevant theory and its Justification 

The large engines (HD (Heavy Duty) truck, aircrafts, etc.) uses two turbos in series, to achieve high speed range without the performance and the ranges limitation of a single turbo engine. The pressure ration split in LP (Low Pressure) and HP (High Pressure). It determines the relative sizes of LP and HP turbochargers. The sizes vary by using the waste gates, VG, bypass, etc. It might require for EGR (Exhaust Gas Recirculation) and other emission measures. 

As turbochargers have to meet different requirements with regard to map height, map width, efficiency characteristics, moment of inertia of the rotor and conditions of use, new compressor and turbine types are continually being developed for various engine applications. Furthermore, different regional legal emission regulations lead to different technical solutions.

The compressor and turbine wheels have the greatest influence on the turbocharger's operational characteristics. These wheels are designed by means of computer programs which allow a three-dimensional calculation of the air and exhaust gas flows. The wheel strength is simultaneously optimised by means of the finite-element method (FEM), and durability calculated on the basis of realistic driving cycles (Ho, Yusoff & Palanisamy, 2013).

CAD-assembled model of a turbocharger

An arbitrary blading provides the ability to fine-tune aero performance and structural response. The bowed blading is utilized to influence the interaction with the recirculating casing treatment and secondary flow development. The high performance capability cross a wide range of features provide by transonic and subsonic blading.

The tailored casing development range is enhanced, based on the comparative CFD analysis. It has minimal impact on efficiency.

The diffuser development design is always a trade-off between the following criteria.

• Performance (pressure recovery)
• Stable operating range
• Overall size

1. The preswirl using inlet guide vanes (IGVs).
2. The performance penalties require careful design to manage.

As the turbochargers have different requirements with regard to map height, map width, efficiency characteristics, moment of inertia of the rotor and conditions of use, new compressor and turbine types are continually being developed for various engine applications. Furthermore, different regional legal emission regulations lead to different technical solutions.

The compressor and turbine wheels have the greatest influence on the turbocharger's operational characteristics. These wheels are designed by means of computer programs which allow a three-dimensional calculation of the air and exhaust gas flows. The wheel strength is simultaneously optimised by means of the finite-element method (FEM), and durability calculated on the basis of realistic driving cycles (Ho, Yusoff & Palanisamy, 2013). 

The limitations of the turbocharged engine’s BMEP limits are set by cylinder pressure limits. It increase fueling at low speed to increase torque and limited by smoke formation. The boost limit at high speed for the exhaust gas temperature or turbocharger speed limits. It’s both are affect the turbine life. 

This chapter effectively delivered the important specifications and design of the project. The engineering design work and development process were discussed. The limitations and the design problems were listed out, where turbocharged engine’s BMEP limits are set by cylinder pressure limits. Moreover, the fueling at low speed is increased to maximize the torque and it is limited by the smoke formation. The boost limits the exhaust gas temperature at high speed. However, it is determined that there will be negative impact on the turbine’s shelf life. The resources required for the project are mentioned. Series Turbocharging-Heavy-Duty Applications is considered as the relevant theory to be applied. It is found that the compressor and turbine wheels influences the operational characteristics of the turbocharger. Computer programs are utilized for designing the wheels, which simplifies calculating the air and exhaust gas flows. The wheel’s strength is optimized using finite-element method. The realistic driving cycles are used for durability calculation. 

This chapter comprises of solution and validation part, which includes the detailed explanation about the achievements of various objectives that are specified in the project. The validation is nothing but the explanation about the product and it is used for making a clear view on selling the product. The Project explains both the working process of the turbo charger and the Small GT Engine. Data Analysis has also been performed for describing the various factors like efficiency, mass flow rate, boost power capabilities and the speed of the turbocharger (Saadi, 2014).

The turbo charger is one of the part in the small GT Engine which is known as the combination of the compressor and the turbine. The final solution for developing the turbo charger based small GT Engine becomes efficient when the successive factors are achieved during the development. The factors that are to be concentrated to get the best solution are the efficiency of the turbo charger, air flow rate, boost pressure capabilities and the speed of the turbo charger. The displacement of the piston should be increased to get the best solution.

The lubricating oil for the engine is the main thing which helps in improving the efficiency of the engine. The oil which is used in the Engine called Lubricating oil should reach the turbo charger which is considered as the major part of the GT small Engine without any short period of delay. If the oil reaches at the right time, then it becomes effective. The foreign materials that are considered to be a dust particles should not mix with the lubricating oil or it should not reach the lubricating system which may affect the right functioning of the turbo charger (Plaksin, Gritsenko & Glemba, 2015). 

The Small GT Engine has been developed based on the turbo charger. This Gas Turbine Engine works more effectively as it is developed based on the turbo charger gives the greater output. The primary benefit of developing the turbocharger based small GT Engine is the marketing competition. It has the capability to compete in the market because of its efficiency and the cost that is required for operating. The flow that enters the turbine system of the turbo charger based engine is considered to be highly not much steady and the manufacturers who develop GT Engines always prefers using the turbo chargers because of the efficiency and the air flow rate involved in it. It is highly compatible with the compressor maps and this compatibility is attained because of its steady state performance (Unver, Koyuncuoglu, Gokasan & Bogosyan, 2016).

Testing Stages

Stage-1: Ignition system- This system is tested to know how to generate enough voltage for the spark plug to function, in the turbocharger’s design.

Stage-2: Specified fuels- To know how to efficiently ignite gasoline and diesel.

Stage-3: Spark plug and tested placement of fuel nozzle- They are used to determine the sufficient air flow through flame tube orifices.

Stage-4: Tested whether the engine was self-sustaining. 

Test plan is important and it is a written document with certain specifications of the product. The test plan is carried out using a step-by-step process. The test plan is considered as efficient to carry out any project. 

The initial step to be taken place in the test plan is analyzing the finished product, in various means. The product that is developed in this project is Turbo Charger based small GT Engine. Thus, it is essential to analyze the GT Engine and the turbo charger by checking its functionality. 

The design test strategy is to check the whole design of the product. In the design test strategy, the main parts of the Engine has to be tested. The turbo charger is the main part of the Gas Turbine Engine. Turbo charger is defined as the combination of compressor and turbine which is used in developing the Engine. Unit testing has to be performed which is used for testing the each and every part of the GT Engine. In the turbocharger, the parts such as control system, compressor, bearing system and the turbine has to be tested individually. 

The objective of testing is to check the working process of the small GT Engine and this should be achieved to produce the error free product to the customers. The goal is to produce the final product to the customers without any delay and error.

The testing criteria can be defined as two different types such as entry criteria or exit criteria. Entry criteria is called as the activities that are presently in progress in the developing project. If the development team reports that the number of failed test cases are about 30%. Then it is very important to find out the failed test cases and they should work to make the test cases to pass. Exit criteria is nothing but there may be any important activity that is to be carried out for exiting from the process. If the success rate of the project can be reached only if the 90% of the test cases are passed, then it is the duty of the testing team to achieve the accuracy of 95%. ("How to Write a Test Plan Document from Scratch (A Real Test Plan for Download) - Software Testing Training on a Live Project Day 3 — Software Testing Help", 2018).

Resources are very fundamental things that are required for doing the project. So the planning has to be done accurately for the allocation of resources. If any shortage of resources occurs in the middle of the project then it will ruin the whole production process. At the same time, the sources should not exceed the limit which may also leads to wastage of resources.

The environment where the testing process to be carried out should be planned in prior. The testing environment is most important and it can be reached only by the cooperation between the development team and the testing team of any developing projects. In our project, the GT Engine has to be tested in a right environment. The number of users who are going to use the GT Engine and the simultaneous processes that are going to be carried out should be found in prior.

Scheduling the project is another important planning in the test plan. Milestones should be fixed for each and every process of the development of the GT Engine based on turbo charger. The schedule should be planned from the initial step called planning process of the project and it should be continued till the last step called delivery is achieved in right time. If the deadline or milestone gets missed for one process then all the other upcoming processes gets spoiled. This may also lead to delay in delivery.

Test deliverables are determined in 3 different phases like before carrying the process of testing, during the testing process and after finishing the process of testing. The deliverables that are to be provided before carrying out the process of testing are Test Plan document, specifying the objectives of the test design and the test case document. The test deliverables that are to be delivered when the test process is in progress are scripts of the test, test data, traceability matrix of the test process and the logs has to be maintained that are shown as errors while the process of testing. After carrying out the process of testing, the deliverables should be results, reports and the guidelines for the procedures of testing. 

This chapter concludes that testing helps in ensuring the working process of the small GT Engine. It is determined that testing plan is beneficial and helps to deliver the final product. Moreover, the GT Engine is determined as effective as it can produce greater output. Marketing competition is the main reason for developing turbocharger based small GT Engine. Because, its efficiency and cost makes it capable to compete in the market. 

This chapter helps to evaluate the results. The results are determined based on Turbocharger Simulation Design, Friction Level, Effective Pressure at Full and Partial Load, Specific Fuel Consumption at Full and Partial Load, Performance Curve of the Compressor, Performance Map of Turbine and Characteristic Value of Turbo Charger. Finally, the outcomes’ Objective Appraisal is determined to see the overall Success of the project.

In the gas inlet 950 degree celcius temperaure is encountered. AT this operating point the inner wall of the turbine near the inlet opens the bypass vale and it becomes hot temperature of the gas in the inlet. The temperature gradient of the drop is 80 degree celcius and this heat dissipates into the environment. the turbine housings are manufactured in the sand casting method and this reference literature provides 850 degree celcius as a maximum temperature. The turbine houd housing is calculated in a load spectra method. 

Here, the friction pressure is increased linerarly and the effective pressure is decreased based on the engine speed. But, it has reciprocal behaviour in the spcific fuel consumption. The specific fuel consumption model is lower than the gas turbine model, but it has equal global tendency. In a given engine speed, the specific consumption is decreased when the load is increased. Hence, this full load engine operates based on the economic way. If the specific fuel consumption is descreased and load is incrased, the speed of the engine moves towards the higher point.

The another main parameter is the time of injection. It plays a vital role in the combustion process. If the injection starts early, it leads to high compression and heat loss because combustion process is takes place in the compression stroke. If the injection process is not carried out in a retarded manner then it leads to expansion loss. Hence, correct injection time is required to achive minimum time.

The operating point of the turbine is selected from the turbine map. The turbine and compressor rotates with same speed, the flow of the compressor is equal to the turbine flow time and it has enough power to drive the compressor to overcome friction. 

Characteristic Value of Turbo Charger

The characteristics value graph of the turbo charger is given below.  

The torque rise percentage is approximately 18.9% is in an aspirated mode and it rose up to 21.6% after service and it reaches 33% after using the turbocharger. The maximum torque percentage is 570 rev/min. It is the maximum torque and it represents the lugging ability of the helicopter.

The torque percentage is increased after the service. Hence, the highest power is incremented ranging from 63 kW to 65.9 k/w rev/min, then it remains at this percentage throughout the working cycle. The maximum power produced by the turbocharger version is 77.1 kW.

The advanced turbo charging technique also increases the exhaust temperature of the gasoline engine. The rated output is 0.75 to 0.85 when the portion of the fuel is used in the engine. If the ratio of air is increased from 0.9 to 1.0. Then the user can save the fuel up to 20%. But it also increases the exhaust temperature of the engine up to 1050 degree Celsius and it places a new demand for the turbo charger.

The results are evaluated for the stagnation temperature in tube 1 which has three zones. The total hole area is 5.01. The average stagnation temperature of the combustion chamber is 2000 degree F. In a distributed analysis, the post processing is performed with high pass filter and it is moved to the average filter of the data to reduce noise pollution.

The first modified hold design has 5.97 inches hole area which is 19% increase from the initial design. The average temperature of the trial run is 2240 F and it is higher than the initial design. When the hold area is increased, the amount of intake air also increased and it leads to the increase in the temperature and reduces the richness of the mixture.

The second modified temperature of the hole design has 8.16 inches and it is 63% increase from the initial design, 37% increase from first modification. The average stagnation temperature produced in the trial run is 2260F which is increased from the initial design and it has marginal increase from the first modification. Then the air fuel ratio is increased in this second modification and it has small increase in the stagnation temperature. It denotes the mixture has optimum air fuel ratio and it is further increased in an oversaturated air mixture.

Now, the stagnation temperature of the hole’s design with Tube 2 is considered. The initial design of tube 2 has 2.94 inches whole area and it produces average stagnation temperature upto 2250 F. Here the hole’s area is reduced when comparing with tube 1. Hence it increases the temperature to indicate the increased air and it reduces the richness of the mixture. The hole’s design stagnation temperature is given below.

The second modified temperature for hole design with tube 2 has 4.15 inches hole area which is 42 % increase from the initial design and 25 % increase from the first modified design. It produced average stagnation temperature of 2300F which is higher than the initial modification.  Then the air fuel ratio is increased for this modification. It has small increase in the stagnation temperature and it has optimum ratio of air fuel. 

The third modified design with tube 2 has 6.63 inches as total hole area and it has 126% increase from the initial design and 60% increase from the second modification. The average stagnation temperature is 227⁰ F which is lower than the previous modifications. Hence te mixture become lean and it deceased the temperature. The ratio of air fuel exceeded from the optimum value. 

The results are determined. It is observed that, specific fuel consumption model is lower than the gas turbine model, but it has equal global tendency. Right injection time is necessary for getting minimum time. It is also understood that the turbine and compressor rotates with same speed, it has equal turbine flow time and contains sufficient power to overcome friction. 

The met objectives and the evidences of the deliverables are discussed in this chapter. This chapter acts as a proof to show that the desired objectives of the project are accomplished. The helicopter using turbo engine. This engine achieved improvement in the engine’s flexibility and the engine’s speed is low particularly in acceleration. It achieved excellent response and high torque at high performance, at high speeds as well as at low engine speed. The first time used turbo engine does not work properly in the helicopter and its response engine is late. This attempt is called as "turbo gap". The engine DV4C/DV6D TED4 increased the output, which was achieved in intercooler for the first time on a production helicopter. It is due to the improvement of working in change from hot turbo charger to cooling air. The engine has achieved reduced pressure without the engine losing any of its power. Further, the achievement of engine system is to develop 420 bhp at 6000 rpm, where the speed reaches top 189 mph or 305 km/h. The achieved fuel consumption is 18 percent lower than on the former model.

The achievement of engine is great both in operating and in fuel economy. The fuel economy and lower emission is under part load. The high torque and maximum output of load is uncompromising, then cam contours with vale stroke, which is achieved at 10 millimeters or 0.39. 

After selecting the required and practically possible power output “Pb”, the power level is verified that actually doesn’t need more bme. Practically, if Pbme≤ 1250, then kPa can be easily achieved. Then, later evaluate mf =PB× BSFC. Here, for BSFC this value uses a realistic value i.e., a well-designed engine uses “ss”. This design can accomplishes 0.2<BSFC<0.25 kg/kWh.

Evaluate ma =mf× (A/F). The turbocharged engine utilizes the ratio A/F that is achieved for the Cl engine which runs on diesel is 25< (A/F) <32.

The compressor’s performance is operating the rated load and engine’s speed is achieved. 

All the specified objectives are met. The evidenced deliverables are provided. The results are evidenced by determining how the engine performs with the help of power compressor and turbine characteristics. The accomplishment of compressor’s performance operating at the rated load and the accomplishment of engine’s speed is determined. 

Conclusion 

Regardless of multiple alternatives for fuel in the market, ICE’s reliability and efficiency is valued more (Babcock, 2014). It is concluded that the project aimed on developing a turbo-based small GT engine, using a conventional turbocharger. The suitable charger for this project is identified. The working principles of turbocharger and Gas Turbine (GT) engines are studied briefly. The connection with the turbocharger is represented. The related components are investigated. Advancement in the internal combustion engines are reviewed briefly. Hence, the project’s objectives are successfully met, where the CAD design to show the project’s working is provided; the working principles of turbocharger and GT engine are discussed; compressor map analysis of the turbo charger is provided, which helps to explain the efficiency, mass flow rate, boost pressure capabilities and turbo speed. Therefore, all the details about the project are investigated to avoid missing any essential information of the project.

The specifications and design of the project are studied, to understand the engineering design work, design problems, project resources, relevant theory, development process and limitations.  It is determined that the turbocharger, compressor and engine are the components that are highlighted. Turbocharger (TD02H2-07TVT-2.1) is used for a better understanding of applying the turbo charger. Helicopter Turbo Shaft ATR-Z2 is the helicopter engine, which is the small GT engine considered for understanding the engine’s function. Henceforth, rather than upgrading the turbo charger, the turbocharger in this project enhances its engine’s power generation. Generally, a turbo charger is powered by a turbine driven by the engine's exhaust gas. The turbocharger enhances the power generated by the engine and uses the power that is bound to go waste in the engine.

The theory applied is, Series Turbocharging-Heavy-Duty Application. It is determined that testing plan is essential and plays a major role in delivering the product. GT Engine is concluded as effective, because it produces greater output. To develop turbocharger based small GT Engine, Marketing competition is the basic reason. Turbocharger based small GT Engine has both efficiency and cost-effective aspects to compete in the market.

It is concluded that, when compared to specific fuel consumption model, gas turbine model is superior. However, they share equivalent global tendency. Right injection time is necessary for getting minimum time. It is also understood that the turbine and compressor rotates with same speed, it has equal turbine flow time and contains enough power for overcoming friction.

Further, the compressor map is discussed for connecting the engine and the turbo charger. The solid works model is provided. Effective solution is identified and convincing validation is also provided. The test plan is delivered. Finally, the results are analyzed, then the outcome’s objective appraisals are also determined and the overall success of the project is represented. The evidenced deliverables of the project are discussed with necessary recommendations.

Therefore, the compressor’s performance operates at the rated load and the engine’s speed is achieved.  The results are evidenced by determining how the engine performs with the help of power compressor and depending on the characteristics of the turbine.

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