السيارة هيونداي فيرنا افضل سيارة موفرة للبنزين

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تعد السيارة هيونداي فيرنا من افضل سيارة موفرة للبنزين وسوف نوضح بعض المعلومات عن استهلاك الوقود ونبزه عن شركة هيونداى. السيارة هيونداي فيرنا افضل سيارة موفرة للبنزين ما هى السيارة هيونداي فيرنا حصلت هذه السيارة علي المركز الاول كاقل سيارة استهلاكا للوقود ، حيث يمكنها قطع مسافة 100 كلم بمعدل 6,8 لتر من الوقود بالنسبة للسيارات المانيوال ، اما عن السيارات الاوتوماتيك فيمكنها قطع نفس

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منتدى الفيديوهات و الكورسات و الاسطوانات التعليمية

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Combustion and Combustion Chambers | What does it mean When an Engine Detonates | What is Pre-ignition Knock | Types of Combustion Chamber

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Three phases of combustion in S.I. Engines:

01-three phases of combustion in SI engines

  1. Ignition Lag or Delay Period:

It is the duration between the occurrence of the spark at the spark plug and the duration of the combustion curve from the motor curve. Factors influencing this phase are:

  • Nature of fuel
  • Mixture ratio
  • Initial temperature
  • Pressure
  • Temperature of the flame between the spark plug electrodes

SOI – Start of Ignition; EOI – End of Ignition

Second phase or Rapid combustion chamber:

It starts when the combustion curve deviates from the motor curve and lasts till the maximum pressure is reached

Third phase or After Burning:

This phase occurs between points of maximum pressure and maximum temperature

01-regular combustion - combustion process steps

Detonation:

01- detonation in IC Engines - Knocking in SI Engines

An uncontrolled explosion of the unburnt air – fuel mixture in the engine cylinder occurring after the regular combustion of some of the charge caused by the spark at the spark plug

Factors influencing detonation:

  • Factors concerning engine
    • Compression ratio
    • Engine Dimensions
    • Throttle opening
  • Spark advance
  • Spark plug location
  • Combustion chamber design
  • Cooling system
  • Carburization
  • Engine speed
  • Valve timing
  • Turbocharging
  • Factors Concerning Fuel
    1. Paraffins
    2. Naphthene's
    3. Aromatics
    Factors concerning air
    1. Temperature
    2. Density
    3. Humidity
    Mixture strength
    1. Effect of detonation:

    2. Inefficient combustion
    3. Loss of power
    4. Local overheating
    5. Mechanical engine failure

    Prevention of Detonation:

    1. Anti – knock agents
    2. Cooling of the charge
    3. Reducing the time factor

    Octane rating:

    01-KNOCK RATING - OCTANE RATING OF FUELS

    Octane number of any fuel is the percentage of is-octane by volume in the mixture of is-octane and normal heptane which gives the same anti-knock characteristics as the fuel under standard test conditions.

    There are two methods of finding octane ratings:
    1. CFR research method (RON)
    2. CFR motor method (MON)

    (RON – MON) is called Fuel sensitivity

    Pre-ignition:

    01- Preignition in IC Engine - detonation in IC Engines - Knocking in SI Engines

    The phenomenon of a hot spot, such as  a glowing spark or deposit, igniting the air fuel mixture earlier than the spark plug

    01 - preignition - Spark plug igniting the air fuel mixture

    01-preignition steps - combustion process steps - Failures in combustion processes

    Terms relating to rate of combustion:

    1. Squish
    2. Quench area
    3. Turbulence

      Considerations affecting combustion chamber design:

      1. Swirl – It is rotational flow of charge within the cylinder
      2. Swirl ratio – It is the ratio of the angular rotational speed of air about the cylinder axis to the crank shaft rotational speed
      3. Surface to volume ratio

      Combustion chambers for S.I. Engines:

      1. Side – Valve type
      2. 01- side valve type Combustion Chamber
      3. Wedge type
      4. 01-wedge shape combustion chamber
      5. Inverted bath tub type
      6. 01- Inverted bath Tub type Combustion chamber for Diesel Engines
      7. Flat head type
      8. 01-flat head type combustion chamber
      9. Hemispherical type
      10. 01-hemi spherical type combustion chamber
      11. Stratified charge type
      12. 01-stratified charge type combustion chamber
      13. Multi – valve type
      14. 01-multi valve type combustin chamber
      15. Split level type
      16. Twin spark plug type
      17. 01-twin spark plug type combustion chamber

      Desirable factors for combustion chambers in S.I. Engines:

      1. Smallest possible ratio of surface area of chamber to its volume
      2. Shortest travel distance for the flame front
      3. Adequate swirl of the incoming mixture
      4. Sufficient cooling of the exhaust valve
      5. Provision for cooling of the spark plug by the incoming fresh air
      6. Adequate sizes and numbers of inlet and exhaust valves

      Four stages of combustion in C.I. Engines:

      1. Ignition delay
      2. Rapid or uncontrolled combustion
      3. Controlled combustion
      4. After burning

      Cetane number:

      Earlier it was defined as the percentage of cetane in a mixture of cetane and a-methylnaphthalene, which has the same diesel knock characteristics as  the fuel under test. Recently, alpha methylnaphthalene has been replaced by a more stable compound, heptamethylnonane has been replaced by a more stable compound, heptamethylnonane, which having a slightly better knock rating has given cetane number of 15. Most diesel fuels for high speed engines have cetane numbers from 45 to 55

      Comparison between Detonation and Diesel knock:

      1. To avoid detonation, auto – ignition of the end –gas has to be prevented; whereas to avoid diesel knock, earliest possible auto – ignition should occur
      2. Fuels having higher octane rating have poor cetane rating and vice versa
      3. Compression ratio has to be limited in case of SI engines, beyond which detonation would occur. However, in case of CI engines, higher the compression ratio, lesser possibility of Diesel knock occurring
      4. Large cylinder size promotes detonation, whereas diesel knock is reduced with the same

      01-how knocking occurs in a Diesel engine steps

      Combustion chambers for C.I. Engines:

      1. Direct Injection type or Open type
      2. Turbulent or Swirl type
      3. Pre-Chamber type


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      Engine Combustion and Fuel Properties | Types of Auto Engine Fuels | Calorific Value of Fuels

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      Important properties of Engine fuel:

      • Knock rating
      • Volatility
      • Calorific value
      • Gum content
      • Sulphur content
      • Aromatic content

      Requirements of an ideal Engine Fuel:

      • Knock resistant  –  Octane number
      • Readily mix with air – Volatility
      • Clean – Contamination
      • Non corrosive – Sulphur content
      • Not form gum – Gum content

      Knock Rating:

      Knock rating of a fuel is essentially a direct comparison of the intensity of the knock produced by it with that of a standard fuel. Chemical analysis or Bomb Explosions methods have been used to find out the knock ratings. Standard fuels used are heptane, isooctane.

      01-KNOCK RATING - OCTANE RATING OF FUELS

      There are several methods by which the knock rating of SI fuel could be rated:

      • Highest useful Compression ratio
      • Octane number
      • Sensitivity
      • Performance Number

      Many design and operating factors affect the Knock ratings. The important properties are:

      1. Compression ratio
      2. Engine Speed
      3. Output
      4. Atomization of fuel and duration of injection
      5. Injection timing
      6. Quality of the fuel
      7. Intake temperature

      Volatility:

      Fuel volatility is the tendency to evaporate under a given set of conditions with which the liquid changes to vapour. Methods used to find the volatility are ASTM distillation test and Reid vapour test. Normally higher volatility reduces the HC emission and increases the NOx emissions

      Important properties of fuel volatility are:

      • Hot and Cold start ability
      • Vapour lock
      • Short and long trip economy
      • Smooth running of the engine
      • Engine worm up period
      • Hot stalling
      • Carburettor icing
      • Acceleration
      • Power and Deposit formation
      • Crank case dilution
      • Spark plug Fouling
      • Evaporative losses
      • Varnish and Sludge deposits

      Calorific Value or Heating value:

      Calorific value is the heat released by the fuel when completely burnt and this value determined at constant volume or constant pressure and flue gas is cooled back to the initial ambient temperatures. Ultimate analysis testing method is used to find out the calorific value. Heating value is used for energy content evaluation. Liquid fuels cannot be burnt in liquid form, so it has to be convert to gaseous form. So liquid fuels has to be evaporated.

      01-CALORIC VALUE OF FUEL - HIGHER HEATING VALUE OF FUEL

      Gum content or Deposits:

      The gum content is the non-volatile residue that is left after the evaporation of the sample under controlled conditions. Many fuels oxidize slowly during storage and the sediments that forms may be precipitate and clog filters. When the filtered fuel, containing soluble gum comes in contact with hot metal and it leave hard deposits that clog screens and narrow passages making diesel engines inoperable. Formation of both sediment and hard deposits results from oxidation of fuel. The amount of gum should be as low as possible since the use of fuels with high gum contents can lead to deposits in induction systems or cause intake valves and fuel injectors to stick. Jet Evaporation test procedure is used to determine the existing gum content.

      Sulphur Content:

      When fuel is burnt the sulphur combines with oxygen (SOx) to create emissions that contribute to decreased air quality and have negative environmental and health effects. High sulphur content decreases the catalytic conversion capacity of a system, thus increasing the emissions of Nitrous oxides (NOx), Carbon monoxide (CO), Hydrocarbons and Volatile organic compounds (VOC). Use of Sulphur free fuel will reduce environmental emissions of particulate matter from existing automobiles.

      Aromatic content:

      01-AROMATIC FUELS COMPOUND

      Hydrocarbons (HC) derived from crude oil has aromatic odour. For improving the octane rating of fuels aromatic materials such as Benzene, Toluene, Xylene are used as additives to gasoline.  Methods to find out the aromatics are: Fluorescent indicator absorption, Nuclear magnetic resonance method, Gas chromatography / Mass spectrometry

      Types of Auto engine Fuels and Alternate Fuels:

      01-types of fuels - alternate fuels

      • Conventional Fuels
      • Petrol
      • Diesel
    1. Alternative Fuels
      • Compressed Natural Gas (CNG)
      • Liquified Natural Gas (LNG)
      • Liquified Petroleum Gas (LPG)
      • Alcohols, e.g., Methanol, Ethanol
      • Electricity
      • Hydrogen
      • Bio Diesel
      • P-Series
    2. 01-alternate fuels - liquified petroeum gas - Compressed natural gas - liquified natural gas - LPG, CNG, LNG


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      NDT Weld inspection for Aero Components | NDT Inspection and Testing | Ultrasonic Weld Inspection

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      What is Non Destructive Testing

      Non Destructive Testing (NDT) is a method of testing the material's characteristics such as physical, chemical and structural components to perform their function in a cost effective way. In this, components are examined / evaluated without destroy / damage of the product. NDT tests conducted in the parts aren't damage the raw materials as such happened in destructive methods and it guaranteeing the safe operation of the parts. NDT is no way alters the components in any type of inspection. NDT is carried out widely for the conditioning monitoring (industrial inspections) of the plants such as aerospace, automobile, manufacturing and construction.

      Non Destructive Testing vs Destructive Testing

      This process is done during the 'production stage' or 'during the service life' or 'during the failure of the components'. Critical material properties are identified by testing under the different loads, where the components properties identified through the specimen failures. Some of the common destructive testing methods are Tensile and Compression Tests, Bending tests, Impact tests, Cupping tests, Hardness test etc. Defect are not identified in destructive testings. Destructive testing is a costliest process due to material loss. Hence it is not suitable for the service material testing.

      Applications of NDT Weld inspection for Aeronautical Components

      Production of Aero components are time consuming, complex designs and the components are very costly. Hence many components in aeronautical industries are keen to watch the parts.

       

       

      List of NDT Inspections

      1. Ultrasonic Testing

      for Seamless tubes, Inspection, crack detection, materials characterization studies, Thickness measurement,

      2. Infrared and Thermographic Testing

      3. Visual Inspection

      Corrosion damage in Built-up structure, Pitting on the exposed surface

      4. Liquid Penetrant Testing

      5. Magnetic Particle Testing

      6. Eddy current theory

      Abrupt changes in the components geometry, Cracking,

      7. Radiography Testing

      8. Acoustic emission Testing

       

       

       



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      Types of Pneumatic Conveyor | Vacuum and Positive Pressure Pneumatic Conveying Systems | Dense Phase Pneumatic Conveying System

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      Classification of Pneumatic Conveying Systems

      Pneumatic conveying systems can be classified on different basis of consideration. These basis are listed below:

      • On average particle concentration (modes)
      • On air pressure (Types of systems)
      • On air supply arrangement
      • On solid feeder type

      Of these, the first two are very important and often influence the choice of the specific design for a given material, loading and delivery condition and the distance to be covered.

      01-pneumatic-conveying system plant - Coffee conveyor plant

      Classification based on Average Particle Concentration – Modes of Conveying:

      01-dilute phase - dense phase - plug phase - conveying of particles

      Depending on the mass flow ratio, defined as the ratio of mass of particles conveyed to the mass of fluid used to convey, pneumatic conveying system may be classified into two modes; namely

      1. Dilute phase
      2. Dense phase

      01- DILUTE PHASE - DENSE PHASE - CONVEYING OFGRAIN PARTICLES IN VACUUM CONVEYOR - PNEUMATIC CONVEYOR

      If the mass flow ratio is low, the system is said to operate in dilute phase. Whereas, if the mass flow ratio is high, the system is said to operate in dense phase. If the mode of operation of a system is in dilute phase, the probable range of mass flow ratio is 0 – 15. The dense phase system operates at mass flow ratio over 15.

      In a dilute phase system the material is carried through the pipeline by a large volume of air having high velocity but relatively low pressure. The stream of air or gas carries the material in suspension in the pipeline as discrete particles owing to lift and drag forces acting on each particles. The distribution of particles over the cross section of the pipe is fairly uniform. In order to keep the particles in suspension, the air must possess a minimum velocity, called the pick up velocity. The pick up velocity for a particular material depends on many factors, like, the shape, size, specific weight of material and inclination of the pipeline.

      01-dilute phase pressure conveying system

      If the velocity of air is gradually lowered down below what is required to keep the particles in suspension, the particles gradually settle down and form dunes at the bottom of the pipeline all along the length of the pipe. In this condition the material is about to choke the pipeline and if the pressure is increased these dunes and plugs of materials may move along the pipeline causing a dense phase flow. In a dense phase flow usually the velocity of fluid is much lower than the minimum velocity required for a dilute  phase flow. The distribution of particles over the cross section of the pipe is non uniform. At the lower part of the pipe there is slow moving dunes or plugs of material and the upper part of the cross section of the pipe is filled with certain proportion of finer particles in suspension in a state of dilute phase.

      01-dilute phase pressure conveying system - Pneumatic conveying system

      01-dense phase pneumatic conveying system

      The maximum mass flow ratio achievable for a dense phase flow depends on many factors like the nature of materials and air velocity. It is usually greater than 30

      Classification based on Air Pressure:

      Based on air pressure, Pneumatic conveying systems may be classified as follows:

      • Low pressure systems, in which the operating air pressure is about 1 atmosphere (760 mm Hg). This type of systems may be further sub classified into
      • Positive pressure system
      • Negative pressure system
      • Combined positive – negative pressure system
    4. Medium pressure system
    5. High pressure system
    6. 01- pneumatic-conveyor-systems - positive conveying - negative conveying



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      History of Pneumatic Conveyors | Pneumatic Capsule Transport

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      01-pneumatic-conveying system plant - Coffee conveyor plant

      Historical Development:

      The basic Principles of Pneumatic conveying stated by Great Alexander in 100 BC itself. In pre historical age Romans used Water supply pipelines and sewage disposable systems. Chinese conveyed Natural gas through Bamboo's. These are the evidence for transporting physical objects in Pneumatic tubes.

      The first industrial application of pneumatic conveying was probably in the form of capsule transportation system in which materials are enclosed in cylindrical or spherical capsules of diameter only slightly less than that of the pipe line and then use the gas or liquid to propel the capsules from one end of the pipe line to the other. The first pneumatic capsule system was built and demonstrated in England in 1820's by John Vallance. Considerable work on pneumatic capsule transport was undertaken by Pneumatic Despatch Company who laid an experimental tube, about 400 meters in length, along the bank of the river THAMES in London. Various similar tunnels and capsule systems were constructed in England to carry letters and parcels. Attempts were made in London and New York around 1860's to use pneumatic capsule systems to carry passengers, but these attempts proved unsuccessful due to practical difficulties with human load. In 1864, Pneumatic railway line was built in Crustal palace to move a carriage, which had been fitted with a sealing diaphragm.

      01-pneumatic conveying capsule line

      01-pneumatic conveying tube - layout of pneumatic transport system

      01-Concept model of vaccum tube trains

      In 1847, Peugeot plant in France used pneumatic conveying plant for exhaust dust from number of grind stones with the help of an exhaust fan

      01-first pneumatic conveying system

      It was in 1866 that a demonstration was arranged by B.E. Startevant to show that solid particles can also be conveyed directly by a stream of air through a pipeline. The first experimental type of pneumatic conveyors were fan driven vacuum systems employed to transport food grains and sawdust. From the early years of 20th century high pressure air was employed in pneumatic conveying. In mid 1920's the technique of fluidisation discovered and since then the technology of pneumatic conveying has grown enormously since 1970's because of its suitability for modern industrial processes and economies of bulk handling methods. During the first World War, the development of pneumatic conveying was influenced by the high demand for foods, labour scarceness and risks of explosion. Since the pneumatic conveying systems were seen as the answer for those situations, so a huge evolution of pneumatic transport was achieved during that time period. In the post war period, pneumatic conveying systems were used for more industrial related materials like coal and cement. Beginning of theoretical approaches, invention of blowers, introduction of batch conveying blow tanks etc., were among the highlighted milestones of the evolution of pneumatic transport systems during the era.

      Now-a-days, pneumatic handling of solids is common place in industries like pharmaceutical, cement, food, chemical, glass, plastic and mining etc. Some industries have transport objects for the distance of more than 40 km, material flow rate of few hundred tons per hour and solid loading ratio of more than 500 also possible.



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