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KNOCKING IN IC ENGINES

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Published in: Electronics | Physics
10,929 Views

KNOCKING IN IC ENGINES

Raja H / Kolkata

4 years of teaching experience

Qualification: B.E.(Production Engineering)

Teaches: Algebra, Mathematics, Physics, IIT JEE Mains, WBJEE, Mechanical

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  1. PRESENTED BY: Raja Hossain
  2. KNOCKING IN IC ENGINE combustion Abnormal occurring in the combustion chamber give sudden pressure rise accompanied by a metallic, hammer like sound leading to loss of performance and possible engine damages. This abnormal combustionqs commonly known as "Knocking Combustion'
  3. CLASSIFICATION OF IC ENGINE INTERNAL COMBUSTION ENGINE COMPRESSION IGNIT10N SPARK IGNITION ENGINE OR GASOLINE ENGINE ENGINE OR DIESEL ENGINE
  4. -=-SPARK IG TIONÅ ENGINE
  5. SECTIONAL VIEW OF s.l. ENGINE I 1. j I INLET MANIFOLD V VALVES P PISTON R CONNECTING ROD C CRANK SHAFT S SPARK PLUG E ->EXHAUST MANIFOLD W WATER JACKETS
  6. OTTO CYCLE IN Sl ENGINE Otto Cycle pv Diagram Otto Cycle Ts Diagram
  7. STAGES OF COMBUSTION IN SPARK IGNITION ENGINE homogeneous air-fuel mixture is introduced into the combustion chamber. is initiated between Spark Plug spark Electrodes. The spark spreads acrossffle combustible mixture. - A single definite flame front progress through the charge.
  8. NORMAL COMBUSTION 00 SPARK CCCURS. COMBUST)ON BEGINS FIA.ME FROST MOVES otrr COMBUSTION NEARLY COMPiÆIE COMB('SnoS COMrtS.T PEAK PRESSURE IGNITION COMPRESSION BDC TDC POWER BDC
  9. ABNORMAL OR KNOCKING 00 COMBUSTION SPARX OCCURS COMBUSTION BEGINS FLAME FROST MOVES otrr IGNITION COMPRESSION COMBUSTtON NEARLY COMPLETE BDC TDC CRANK ANGLE END OASES DETONATE PEAK PRESSURE POWER BDC
  10. KNOCKING DUE TO SURFACE IGNITION What is surface ignition? It is defined as the initiation of the flame front by a hot surface other than the spark. Mostly surface ignition occur due to carbon deposition.
  11. EFFECT OF KNOCKING , NOISE AND ROUGHNESS , MECHANICAL DAMAGE , CARBON DEPOSITS , INCREASE IN HEAT LOSS , DECREASE IN POWER OUTPUT AND EFFICIENCY
  12. EFFECT OF KNOCKING ON ENGINE PISTON Engine piston subjected to extended operation under knocking conditions shows tremendous damage. Lower temperature combustion would reduce nitrogen oxide emissions and protect the engine from the harmful effects of auto ignition and knocking.
  13. CONTINUED.... Knocking resulting in carbon deposits and mechanical damages of the engine.
  14. CONTROL OF KNOCKING REDUCING COMPRESSION RATIO REDUCING INLET TEMPERATURE REDUCING INLET PRESSURE RETARDING SPARK LOWERING POWER OUTPUT INCREASING TURBULENCE DECREASING FLAME TRAVEL DISTANCE INCREASING ENGINE SPEED MODIFYING SPARK PLUG LOCATION COMPACT COMBUSTION CHAMBER ADDITION OF ANTI-KNOCK FUEL ADDITIVES
  15. FUNCTIONS OF ANTI-KNOCK FUEL ADDITIVES Anti-knock fuel additives raises the octane number of the fuel. Higher octane ratings correlate to higher activation energies. Activation energy is the amount of energy necessary to start a chemical reaction. Since higher octane fuels have higher activation energies, it is less likely that a given compression will cause knocking Example: Tetra-ethyl lead Methyl tert-butyl ether 1,2-Dibromoethane 1,2-Dichloroethane Fe rrocene
  16. dNLDNg NOILINDI NO I ? SSAHdVNO D
  17. SECTIONAL VIEW OF COMPRESSION IGNITION ENGINE Intake Valve Air Crank Disk Fuel Exhaust Valve Exaust Gas Piston Cyln&r
  18. DIESEL CYCLE IN Cl ENGINE Diesel Cycle Pv Diagram Diesel Cycle Ts Diagram
  19. STAGES OF COMBUSTION IN COMPRESSION IGNITION ENGINE Liquid fuel is injected under a high pressure of 110 to 200 kgf/cm2 into the compressed and highly heated air inside the combustion chamber. The fuel undergoes ignition delay period during which some fuel has been admitted but not yet been ignited. Rapid or uncontrolled combustion following ignition. aControIIed combustion QAfter burning
  20. STAGES OF COMBUSTION ON PRESSURE VS TIME DIAGRAM 80 60 Start of combustion 40 Start of injection 0.001 s Compression pressure Motoring (non-firing) 20 100 80 Atmospheric 60 40 20 TDC 20 40 60 80 Tirne (de ee of crankshaft rotation) 100
  21. COMPRESSION IGNITION ENGINE KNOCKING When the ignition delay is longer, the actual burning of first few droplets of fuel is delayed. A greater quantity of fuel droplets accumulate in the chamber. On commencing of burning, the additional fuel cause too rapid rise of pressure. High pressure differentials thus created causes violent vibrations known as knocking.
  22. KNOCKING COMBUSTION IN DIESEL ENGINE IGNITION COMPRESSION BDC TDC CRANK ANGLE POWER BOC
  23. COMPOSITION FACTOR The detonation or Knocking in CI engine can be reduced by using certain fuel additives which would increase the cetane number of the fuel. The two chemical drops normally used are, ETHYL NITRATE 33gms/US gallon 29gms/US gallon AMYL NITRATE Higher the cetane number of the fuel, lower is the chances of knocking.
  24. ANTI-KNOCK FUEL ADDITIVES (CETANE BOOSTERS) Several anti-knock fuel additives commonly known as cetane boosters are added to the fuels to prevent the knocking Of the diesel engines. Example: I-nitro 2 I-nitro 2- — OCtene 3-methyl-1-nitro-2-pentene 3-methyl-1-nitro-2-hexene
  25. DIFFERENCE IN KNOCK BETWEEN Sl & Cl ENGINE In SI engine knocking occurs after the peak pressure rise but in CI engine it occurs before the peak pressure rise. Pre-ignition may occur in SI engine but in CI engine there is no chance of pre- ignition. Pressure rise is more rapid in case of SI engine. In CI engine little knocking may always present and when it becomes severe it is considered as knock.
  26. ????? ???
  27. PRESENTED BY: Raja Hossain
  28. KNOCKING IN IC ENGINE Abnormal combustion occurring in the combustion chamber give sudden pressure rise accompanied by a metallic, hammer like sound leading to loss of performance and possible engine damages. This abnormalÆombustionMs commonly known as "Knocking Combustion'
  29. CLASSIFICATION OF IC ENGINE INTERNAL COMBUSTION ENGINE COMPRESSION SPARK ENGINE ENGINE OR OR DIESEL ENGINE GASOLINE ENGINE
  30. PRESENTED BY: Raja Hossain
  31. IG TIONÅ ÉNGINE
  32. KNOCKING IN IC ENGINE Abnormal combustion occurring in the combustion chamber give sudden pressure rise accompanied by a metallic, hammer like sound leading to loss of performance and possible engine damages. This abnormalÆombustionMs commonly known as "Knocking Combustion'
  33. SECTIONAL VIEW OF s.l. ENGINE I 1 j I INLET MANIFOLD V VALVES P PISTON R —CONNECTING ROD C CRANK SHAFT S SPARK PLUG E ->EXHAUST MANIFOLD W WATER JACKETS
  34. CLASSIFICATION OF IC ENGINE INTERNAL COMBUSTION ENGINE COMPRESSION SPARK ENGINE ENGINE OR OR DIESEL ENGINE GASOLINE ENGINE
  35. OTTO CYCLE IN ENGINE Otto Cycle pv Diagram Otto Cycle Ts Diagram
  36. IG TIONÅ ÉNGINE
  37. STAGES OF COMBUSTION IN SPARK IGNITION ENGINE introduced into the combustion chamber. is initiated between Spark Plug spark Electrodes. The spark spreads acrossfthe combustible mixture. - A single definite flame front progress through the charge.
  38. SECTIONAL VIEW OF s.l. ENGINE I 1 j I INLET MANIFOLD V VALVES P PISTON R —CONNECTING ROD C CRANK SHAFT S SPARK PLUG E ->EXHAUST MANIFOLD W WATER JACKETS
  39. PRESSURE
  40. OTTO CYCLE IN ENGINE Otto Cycle pv Diagram Otto Cycle Ts Diagram
  41. ABNORMAL OR KNOCKING 00 COMBUSTION SPARX OCCURS. COMBUSTION BEGSNS YUME FROST UOVFS otrr IGNITION COMPRESSION COMBUSTION NEARLY COMPLETE BDC TDC CRANK ANGLE END OASES DETONATE PEAK PRESSURE POWER BDC
  42. STAGES OF COMBUSTION IN SPARK IGNITION ENGINE introduced into the combustion chamber. is initiated between Spark Plug spark Electrodes. The spark spreads acrossfthe combustible mixture. - A single definite flame front progress through the charge.
  43. KNOCKING DUE TO SURFACE IGNITION What is surface ignition? It is defined as the initiation of the flame front by a hot surface other than the spark. Mostly surface ignition occur due to carbon deposition.
  44. PRESSURE
  45. EFFECT OF KNOCKING , NOISE AND ROUGHNESS MECHANICAL DAMAGE CARBON DEPOSITS , INCREASE IN HEAT LOSS , DECREASE IN POWER OUTPUT AND EFFICIENCY
  46. ABNORMAL OR KNOCKING 00 COMBUSTION SPARX OCCURS. COMBUSTION BEGSNS YUME FROST UOVFS otrr IGNITION COMPRESSION COMBUSTION NEARLY COMPLETE BDC TDC CRANK ANGLE END OASES DETONATE PEAK PRESSURE POWER BDC
  47. EFFECT OF KNOCKING ON ENGINE PISTON Engine piston subjected to extended operation under knocking conditions shows tremendous damage Lower temperature combustion would reduce nitrogen oxide emissions and protect the engine from the harmful effects of auto ignition and knocking.
  48. KNOCKING DUE TO SURFACE IGNITION What is surface ignition? It is defined as the initiation of the flame front by a hot surface other than the spark. Mostly surface ignition occur due to carbon deposition.
  49. EFFECT OF KNOCKING , NOISE AND ROUGHNESS MECHANICAL DAMAGE CARBON DEPOSITS , INCREASE IN HEAT LOSS , DECREASE IN POWER OUTPUT AND EFFICIENCY
  50. CONTINUED.... Knocking resulting in carbon deposits —Gild mechanical damages of the engine. -8
  51. EFFECT OF KNOCKING ON ENGINE PISTON Engine piston subjected to extended operation under knocking conditions shows tremendous damage Lower temperature combustion would reduce nitrogen oxide emissions and protect the engine from the harmful effects of auto ignition and knocking.
  52. CONTROL OF KNOCKING REDUCING COMPRESSION RATIO REDUCING INLET TEMPERATURE REDUCING INLET PRESSURE RETARDING SPARK LOWERING POWER OUTPUT INCREASING TURBULENCE DECREASING FLAME TRAVEL DISTANCE INCREASING ENGINE SPEED MODIFYING SPARK PLUG LOCATION COMPACT COMBUSTION CHAMBER ADDITION OF ANTI-KNOCK FUEL ADDITIVES
  53. CONTINUED.... Knocking resulting in carbon deposits —Gild mechanical damages of the engine. -8
  54. CONTROL OF KNOCKING REDUCING COMPRESSION RATIO REDUCING INLET TEMPERATURE REDUCING INLET PRESSURE RETARDING SPARK LOWERING POWER OUTPUT INCREASING TURBULENCE DECREASING FLAME TRAVEL DISTANCE INCREASING ENGINE SPEED MODIFYING SPARK PLUG LOCATION COMPACT COMBUSTION CHAMBER ADDITION OF ANTI-KNOCK FUEL ADDITIVES
  55. FUNCTIONS OF ANTI-KNOCK FUEL ADDITIVES Anti-knock fuel additives raises the octane number of the fuel. Higher octane ratings correlate to higher activation energies. Activation energy is the amount of energy necessary to start a chemical reaction. Since higher octane fuels have higher activation energies, it is less likely that a given compression will cause knocking Example: Tetra-ethyl lead Methyl tert-butyl ether 1,2-Dibromoethane 1,2-DichIoroethane
  56. PRESENTED BY: Raja Hossain
  57. COMPRE ION IGNITION ENGINE
  58. FUNCTIONS OF ANTI-KNOCK FUEL ADDITIVES Anti-knock fuel additives raises the octane number of the fuel. Higher octane ratings correlate to higher activation energies. Activation energy is the amount of energy necessary to start a chemical reaction. Since higher octane fuels have higher activation energies, it is less likely that a given compression will cause knocking Example: Tetra-ethyl lead Methyl tert-butyl ether 1,2-Dibromoethane 1,2-DichIoroethane
  59. COMPRE ION IGNITION ENGINE
  60. KNOCKING IN IC ENGINE Abnormal combustion occurring in the combustion chamber give sudden pressure rise accompanied by a metallic, hammer like sound leading to loss of performance and possible engine damages. This abnormalÆombustionMs commonly known as "Knocking Combustion'
  61. SECTIONAL VIEW OF COMPRESSION IGNITION ENGINE Intake Valve Fuel Exhaust Valve Air Crank Disk Exaust Gas Piston Cyln&r
  62. DIESEL CYCLE IN ENGINE Diesel Cycle Pv Diagram Diesel Cycle Ts Diagram
  63. SECTIONAL VIEW OF COMPRESSION IGNITION ENGINE Intake Valve Fuel Exhaust Valve Air Crank Disk Exaust Gas Piston Cyln&r
  64. CLASSIFICATION OF IC ENGINE INTERNAL COMBUSTION ENGINE COMPRESSION SPARK ENGINE ENGINE OR OR DIESEL ENGINE GASOLINE ENGINE
  65. DIESEL CYCLE IN ENGINE Diesel Cycle Pv Diagram Diesel Cycle Ts Diagram
  66. IG TIONÅ ÉNGINE
  67. STAGES OF COMBUSTION IN COMPRESSION IGNITION ENGINE Liquid fuel is injected under a high pressure of 110 to 200 kgf/cm2 into the compressed and highly heated air inside the combustion chamber. The fuel undergoes ignition delay period during which some fuel has been admitted but not yet been ignited. QRapid or uncontrolled combustion following ignition. QControIIed combustion After burning
  68. STAGES OF COMBUSTION ON PRESSURE VS TIME DIAGRAM 80 60 9.4 40 20 100 Start of combustion Start of injection 0.001 s Compression pressure Motoring (non-firing) 80 Atrnospheric 60 40 20 TDC 20 40 60 80 e of crankshaft rotation) Tirne (de 100
  69. STAGES OF COMBUSTION IN COMPRESSION IGNITION ENGINE Liquid fuel is injected under a high pressure of 110 to 200 kgf/cm2 into the compressed and highly heated air inside the combustion chamber. The fuel undergoes ignition delay period during which some fuel has been admitted but not yet been ignited. QRapid or uncontrolled combustion following ignition. QControIIed combustion After burning
  70. SECTIONAL VIEW OF s.l. ENGINE I 1 j I INLET MANIFOLD V VALVES P PISTON R —CONNECTING ROD C CRANK SHAFT S SPARK PLUG E ->EXHAUST MANIFOLD W WATER JACKETS
  71. STAGES OF COMBUSTION ON PRESSURE VS TIME DIAGRAM 80 60 9.4 40 20 100 Start of combustion Start of injection 0.001 s Compression pressure Motoring (non-firing) 80 Atrnospheric 60 40 20 TDC 20 40 60 80 e of crankshaft rotation) Tirne (de 100
  72. OTTO CYCLE IN ENGINE Otto Cycle pv Diagram Otto Cycle Ts Diagram
  73. COMPRESSION IGNITION ENGINE KNOCKING When the ignition delay is longer, the actual burning of first few droplets of fuel is delayed. A greater quantity of fuel droplets accumulate in the chamber. On commencing of burning, the additional fuel cause too rapid rise of pressure. High pressure differentials thus created causes violent vibrations known as knocking.
  74. KNOCKING COMBUSTION IN DIESEL ENGINE IGNITION COMPRESSION BDC TDC CRANK ANGLE POWER BDC
  75. STAGES OF COMBUSTION IN SPARK IGNITION ENGINE introduced into the combustion chamber. is initiated between Spark Plug spark Electrodes. The spark spreads acrossfthe combustible mixture. - A single definite flame front progress through the charge.
  76. COMPRESSION IGNITION ENGINE KNOCKING When the ignition delay is longer, the actual burning of first few droplets of fuel is delayed. A greater quantity of fuel droplets accumulate in the chamber. On commencing of burning, the additional fuel cause too rapid rise of pressure. High pressure differentials thus created causes violent vibrations known as knocking.
  77. PRESSURE
  78. KNOCKING COMBUSTION IN DIESEL ENGINE IGNITION COMPRESSION BDC TDC CRANK ANGLE POWER BDC
  79. COMPOSITION FACTOR The detonation or Knocking in CI engine can be reduced by using certain fuel additives which would increase the cetane number of the fuel. The two chemical drops normally used are, ETHYL NITRATE 33gms/US gallon 29gms/US gallon AMYL NITRA TE Higher the cetane number of the fuel, lower is the chances of knocking.
  80. ABNORMAL OR KNOCKING 00 COMBUSTION SPARX OCCURS. COMBUSTION BEGSNS YUME FROST UOVFS otrr IGNITION COMPRESSION COMBUSTION NEARLY COMPLETE BDC TDC CRANK ANGLE END OASES DETONATE PEAK PRESSURE POWER BDC
  81. COMPOSITION FACTOR The detonation or Knocking in CI engine can be reduced by using certain fuel additives which would increase the cetane number of the fuel. The two chemical drops normally used are, ETHYL NITRATE 33gms/US gallon 29gms/US gallon AMYL NITRA TE Higher the cetane number of the fuel, lower is the chances of knocking.
  82. ANTI-KNOCK FUEL ADDITIVES (CETANE BOOSTERS) Several anti-knock fuel additives commonly known as cetane boosters are added to the fuels to prevent the knocking Of the diesel engines. Example: — —hex e n e I-nitro 2 I-nitro 2- - octene 3-methyI-1-nitro-2-pentene 3-methyI-1-nitro-2-hexene
  83. KNOCKING DUE TO SURFACE IGNITION What is surface ignition? It is defined as the initiation of the flame front by a hot surface other than the spark. Mostly surface ignition occur due to carbon deposition.
  84. ANTI-KNOCK FUEL ADDITIVES (CETANE BOOSTERS) Several anti-knock fuel additives commonly known as cetane boosters are added to the fuels to prevent the knocking Of the diesel engines. Example: — —hex e n e I-nitro 2 I-nitro 2- - octene 3-methyI-1-nitro-2-pentene 3-methyI-1-nitro-2-hexene
  85. DIFFERENCE IN KNOCK BETWEEN Sl & Cl ENGINE In SI engine knocking occurs after the peak pressure rise but in CI engine it occurs before the peak pressure rise. Pre-ignition may occur in SI engine but in CI engine there is no chance of pre- ignition. Pressure rise is more rapid in case of SI engine. In CI engine little knocking may always present and when it becomes severe it is considered as knock.
  86. EFFECT OF KNOCKING , NOISE AND ROUGHNESS MECHANICAL DAMAGE CARBON DEPOSITS , INCREASE IN HEAT LOSS , DECREASE IN POWER OUTPUT AND EFFICIENCY
  87. DIFFERENCE IN KNOCK BETWEEN Sl & Cl ENGINE In SI engine knocking occurs after the peak pressure rise but in CI engine it occurs before the peak pressure rise. Pre-ignition may occur in SI engine but in CI engine there is no chance of pre- ignition. Pressure rise is more rapid in case of SI engine. In CI engine little knocking may always present and when it becomes severe it is considered as knock.
  88. ????? ???
  89. EFFECT OF KNOCKING ON ENGINE PISTON Engine piston subjected to extended operation under knocking conditions shows tremendous damage Lower temperature combustion would reduce nitrogen oxide emissions and protect the engine from the harmful effects of auto ignition and knocking.
  90. ????? ???
  91. CONTINUED.... Knocking resulting in carbon deposits —Gild mechanical damages of the engine. -8
  92. CONTROL OF KNOCKING REDUCING COMPRESSION RATIO REDUCING INLET TEMPERATURE REDUCING INLET PRESSURE RETARDING SPARK LOWERING POWER OUTPUT INCREASING TURBULENCE DECREASING FLAME TRAVEL DISTANCE INCREASING ENGINE SPEED MODIFYING SPARK PLUG LOCATION COMPACT COMBUSTION CHAMBER ADDITION OF ANTI-KNOCK FUEL ADDITIVES
  93. FUNCTIONS OF ANTI-KNOCK FUEL ADDITIVES Anti-knock fuel additives raises the octane number of the fuel. Higher octane ratings correlate to higher activation energies. Activation energy is the amount of energy necessary to start a chemical reaction. Since higher octane fuels have higher activation energies, it is less likely that a given compression will cause knocking Example: Tetra-ethyl lead Methyl tert-butyl ether 1,2-Dibromoethane 1,2-DichIoroethane
  94. COMPRE ION IGNITION ENGINE
  95. SECTIONAL VIEW OF COMPRESSION IGNITION ENGINE Intake Valve Fuel Exhaust Valve Air Crank Disk Exaust Gas Piston Cyln&r
  96. DIESEL CYCLE IN ENGINE Diesel Cycle Pv Diagram Diesel Cycle Ts Diagram
  97. STAGES OF COMBUSTION IN COMPRESSION IGNITION ENGINE Liquid fuel is injected under a high pressure of 110 to 200 kgf/cm2 into the compressed and highly heated air inside the combustion chamber. The fuel undergoes ignition delay period during which some fuel has been admitted but not yet been ignited. QRapid or uncontrolled combustion following ignition. QControIIed combustion After burning
  98. STAGES OF COMBUSTION ON PRESSURE VS TIME DIAGRAM 80 60 9.4 40 20 100 Start of combustion Start of injection 0.001 s Compression pressure Motoring (non-firing) 80 Atrnospheric 60 40 20 TDC 20 40 60 80 e of crankshaft rotation) Tirne (de 100
  99. COMPRESSION IGNITION ENGINE KNOCKING When the ignition delay is longer, the actual burning of first few droplets of fuel is delayed. A greater quantity of fuel droplets accumulate in the chamber. On commencing of burning, the additional fuel cause too rapid rise of pressure. High pressure differentials thus created causes violent vibrations known as knocking.
  100. KNOCKING COMBUSTION IN DIESEL ENGINE IGNITION COMPRESSION BDC TDC CRANK ANGLE POWER BDC
  101. COMPOSITION FACTOR The detonation or Knocking in CI engine can be reduced by using certain fuel additives which would increase the cetane number of the fuel. The two chemical drops normally used are, ETHYL NITRATE 33gms/US gallon 29gms/US gallon AMYL NITRA TE Higher the cetane number of the fuel, lower is the chances of knocking.
  102. ANTI-KNOCK FUEL ADDITIVES (CETANE BOOSTERS) Several anti-knock fuel additives commonly known as cetane boosters are added to the fuels to prevent the knocking Of the diesel engines. Example: — —hex e n e I-nitro 2 I-nitro 2- - octene 3-methyI-1-nitro-2-pentene 3-methyI-1-nitro-2-hexene
  103. DIFFERENCE IN KNOCK BETWEEN Sl & Cl ENGINE In SI engine knocking occurs after the peak pressure rise but in CI engine it occurs before the peak pressure rise. Pre-ignition may occur in SI engine but in CI engine there is no chance of pre- ignition. Pressure rise is more rapid in case of SI engine. In CI engine little knocking may always present and when it becomes severe it is considered as knock.
  104. ????? ???

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