Components Of an I.C Engines



An engine is a device that converts thermal energy into mechanical work. The thermal energy is produced by the combustion of air fuel mixture inside the cylinder by means of a spark produced by the spark plug. Since it uses thermal energy it is called as thermal engines. It is a source of power for many applications.

Cylinder:

v  It is the part of the engine in which the conversion of thermal energy to

v  mechanical work takes place. The piston reciprocates inside the cylinder. 



v  Since energy conversion takes place inside the cylinder it must withstand high pressure and temperature. 

v  It must be able to resist wear and tear and must dissipate heat. So material selection is an import ant consideration. Ordinary cast iron is used in light duty engines but in heavy duty engines alloy steels are used.

v  The cylinders are provided with liners so that they can be replaced when worn out. Liners are made of nickel chrome iron.

Cylinder head: 

v  The cylinder head closes one side of the cylinder. They are usually cast as a single piece and are bolted to the top of the cylinder. 

v  Between the cylinder and the cylinder head, gasket is provided Gasket is provided in order to act as sealing (to prevent gases escaping during the expansion stroke) and also to reduce shock.

Piston and piston rings:

v  Piston is the main part of the engine. The main function of the piston is to compress the charge and to transmit the gas force to the connecting rod during the power stroke.

v  Piston rings are circumferential rings that are provided in the piston grooves. 

v  The piston rings are not fully circular; there is a clearance (Ring gap) between the two

v  ends. 

v  This is provided because during the expansion stroke piston rings expand.




There are two types of piston rings

v  Compression rings

v  Oil scraper rings


                                                                       Figure 1

v  The upper rings are the compression rings. 

v  They help in sealing and preventing the gas from leaking past the piston into the casing. 

v  The lower rings are the oil scraper rings.

v   They are provided to remove the oil film from the cylinder walls

Connecting rod: 

v  The connecting rod connects the piston and the crankshaft. 

v  The piston is connected to the connecting rod by means of gudgeon pin.

v  It converts the reciprocating motion into rotary motion. 

v  The upper end of the connecting rod is called small head that is connected to the piston and the lower end is called big end.

                                                                     Figure 2


Crankshaft:

v  It is steel forged and smooth finished. Both the ends of the crankshaft are supported in the bearings. 

v  One end is provided with the flywheel. The crankshaft is provided with counter weights for balancing.

                                                                 Figure 3


 Cam and camshaft:

v  The main function of the camshaft is to open and close the valves at the appropriate time.
 The cam is operated by means of gear arrangement driven by the flywheel. 

v  The cam converts rotary motion into linear motion that operates the rocker arm. The motion of the rocker arm operates the valves.

v  Sometimes two camshafts are provided to operate inlet valve and exhaust valve
      separately.
                                                                         Figure 4





Valves: 

v  Valves play a major role in allowing the air fuel mixture into the cylinder (inlet valve) for combustion and also releasing the exhaust gases from the cylinder after combustion (outlet valve).

Manifolds: 

v  There are two types of manifolds

Inlet manifold: 

v  It is a pipe like structure that connects the carburetor with the inlet
valves. The air fuel mixture from the carburettor passes through the inlet manifold to
the inlet valves.
                                   Figure 5
                                             Fig shows A typical six-cylinder manifold

Exhaust manifold:

v  This pipe like structure connects the outlet valve to the atmosphere. The exhaust gas from the cylinder passes through the exhaust manifold into the atmosphere.

 Valve And Port Timing Diagrams

Valve timing Diagram

  • A valve timing diagram is a representation of the positions of the crank when the various operations as inlet valve opening, closing, exhaust valve opening and closing and also the beginning and end of various strokes
  • . The valves cannot open and close abruptly; it requires a finite period of time for its operation so a time advance is given for proper functioning. The timing of the valves is controlled by cam settings.
 Valve timing for 4 stroke petrol (Spark Ignition) engine:

  • Now let us see the various position of the crank when the inlet and exhaust
valves during the various processes. Inlet valve opening: The valve timing is different for low speed and high speed.
  • The inlet valve opens before the piston reaches the TDC during the exhaust stroke. This is to ensure that the fresh charge enters the cylinder as soon the piston as soon as the piston starts to move down.
  • Actual valve timing diagram for actual valve timing diagram for lowhigh speed 4 stroke SI engine speed 4 stroke SI engine
Inlet valve closing:
  • The closing of the inlet valve takes place during the start of compression stroke (i.e. when the piston move from BDC to TDC after finishing suction stroke and the starting of compression stroke).
  • I f the inlet valve is allowed to close exactly at BDC then less charge than the capacity enters during the suction stroke so the inlet valve closing is delayed to 20-25degrees after the crank reaches the BDC position during slow speed and 40-50degrees after the crank reaches the BDC position during high speed.
Exhaust valve opening: 

  • The exhaust valve opens at the end of expansion stroke. The exhaust valve opening is done before the piston reaches the BDC so as to provide more time for all the burnt gases to escape.
  • The opening of the exhaust valve is necessary because if there are some burnt up gases left in the cylinder it may affect the cylinder walls and the spark plug. So the exhaust valve is opened 30-35degrees before BDC for slow speed and 45-50degrees before BDC for high speed.
Exhaust valve closing:

  • The exhaust valve closing is also important to let out all the burnt gases. The time between the exhaust valve opening and the exhaust valve closing determines the amount of burnt gases that escapes.
  •  Usually the exhaust valve is closed 8-10after the piston reaches the TDC position. An important phenomenon in the valve timing diagram is the angle of overlap.
  •  The angle of overlap is the angle for which both the inlet valve and the exhaust valves remains opened. Thus it can be seen that from the diagram the
angle of overlap during slow speed is 5+8=13.

  • The crank position at which ignition occurs is also indicated in the valve timing diagram. The ignition is provided 38-40before TDC during compression.



Posted by at
Labels:

2 comments:

Subscribe to: Post Comments (Atom)

Labels

PROJECTS 8086 PIN CONFIGURATION 80X86 PROCESSORS TRANSDUCERS 8086 – ARCHITECTURE Hall-Effect Transducers INTEL 8085 OPTICAL MATERIALS BIPOLAR TRANSISTORS INTEL 8255 Optoelectronic Devices Thermistors thevenin's theorem MAXIMUM MODE CONFIGURATION OF 8086 SYSTEM ASSEMBLY LANGUAGE PROGRAMME OF 80X86 PROCESSORS POWER PLANT ENGINEERING PRIME MOVERS 8279 with 8085 MINIMUM MODE CONFIGURATION OF 8086 SYSTEM MISCELLANEOUS DEVICES MODERN ENGINEERING MATERIALS 8085 Processor- Q and A-1 BASIC CONCEPTS OF FLUID MECHANICS OSCILLATORS 8085 Processor- Q and A-2 Features of 8086 PUMPS AND TURBINES 8031/8051 MICROCONTROLLER Chemfet Transducers DIODES FIRST LAW OF THERMODYNAMICS METHOD OF STATEMENTS 8279 with 8086 HIGH VOLTAGE ENGINEERING OVERVOLATGES AND INSULATION COORDINATION Thermocouples 8251A to 8086 ARCHITECTURE OF 8031/8051 Angle-Beam Transducers DATA TRANSFER INSTRUCTIONS IN 8051/8031 INSTRUCTION SET FOR 8051/8031 INTEL 8279 KEYBOARD AND DISPLAY INTERFACES USING 8279 LOGICAL INSTRUCTIONS FOR 8051/8031 Photonic Transducers TECHNOLOGICAL TIPS THREE POINT STARTER 8257 with 8085 ARITHMETIC INSTRUCTIONS IN 8051/8031 LIGHTNING PHENOMENA Photoelectric Detectors Physical Strain Gage Transducers 8259 PROCESSOR APPLICATIONS OF HALL EFFECT BRANCHING INSTRUCTIONS FOR 8051/8031 CPU OF 8031/8051 Capacitive Transducers DECODER Electromagnetic Transducer Hall voltage INTEL 8051 MICROCONTROLLER INTEL 8251A Insulation Resistance Test PINS AND SIGNALS OF 8031/8051 Physical Transducers Resistive Transducer STARTERS Thermocouple Vacuum Gages USART-INTEL 8251A APPLICATIONs OF 8085 MICROPROCESSOR CAPACITANCE Data Transfer Instructions In 8086 Processors EARTH FAULT RELAY ELECTRIC MOTORS ELECTRICAL AND ELECTRONIC INSTRUMENTS ELECTRICAL BREAKDOWN IN GASES FIELD EFFECT TRANSISTOR (FET) INTEL 8257 IONIZATION AND DECAY PROCESSES Inductive Transducers Microprocessor and Microcontroller OVER CURRENT RELAY OVER CURRENT RELAY TESTING METHODS PhotoConductive Detectors PhotoVoltaic Detectors Registers Of 8051/8031 Microcontroller Testing Methods ADC INTERFACE AMPLIFIERS APPLICATIONS OF 8259 EARTH ELECTRODE RESISTANCE MEASUREMENT TESTING METHODS EARTH FAULT RELAY TESTING METHODS Electricity Ferrodynamic Wattmeter Fiber-Optic Transducers IC TESTER IC TESTER part-2 INTERRUPTS Intravascular imaging transducer LIGHTNING ARRESTERS MEASUREMENT SYSTEM Mechanical imaging transducers Mesh Current-2 Millman's Theorem NEGATIVE FEEDBACK Norton's Polarity Test Potentiometric transducers Ratio Test SERIAL DATA COMMUNICATION SFR OF 8051/8031 SOLIDS AND LIQUIDS Speed Control System 8085 Stepper Motor Control System Winding Resistance Test 20 MVA 6-digits 6-digits 7-segment LEDs 7-segment A-to-D A/D ADC ADVANTAGES OF CORONA ALTERNATOR BY POTIER & ASA METHOD ANALOG TO DIGITAL CONVERTER AUXILIARY TRANSFORMER AUXILIARY TRANSFORMER TESTING AUXILIARY TRANSFORMER TESTING METHODS Analog Devices A–D BERNOULLI’S PRINCIPLE BUS BAR BUS BAR TESTING Basic measuring circuits Bernoulli's Equation Bit Manipulation Instruction Buchholz relay test CORONA POWER LOSS CURRENT TRANSFORMER CURRENT TRANSFORMER TESTING Contact resistance test Current to voltage converter DAC INTERFACE DESCRIBE MULTIPLY-EXCITED Digital Storage Oscilloscope Display Driver Circuit E PROMER ELPLUS NT-111 EPROM AND STATIC RAM EXCITED MAGNETIC FIELD Electrical Machines II- Exp NO.1 Energy Meters FACTORS AFFECTING CORONA FLIP FLOPS Fluid Dynamics and Bernoulli's Equation Fluorescence Chemical Transducers Foil Strain Gages HALL EFFECT HIGH VOLTAGE ENGG HV test HYSTERESIS MOTOR Hall co-efficient Hall voltage and Hall Co-efficient High Voltage Insulator Coating Hot-wire anemometer How to Read a Capacitor? IC TESTER part-1 INSTRUMENT TRANSFORMERS Importance of Hall Effect Insulation resistance check Insulator Coating Knee point Test LEDs LEDs Display Driver LEDs Display Driver Circuit LM35 LOGIC CONTROLLER LPT LPT PORT LPT PORT EXPANDER LPT PORT LPT PORT EXTENDER Life Gone? MAGNETIC FIELD MAGNETIC FIELD SYSTEMS METHOD OF STATEMENT FOR TRANSFORMER STABILITY TEST METHODS OF REDUCING CORONA EFFECT MULTIPLY-EXCITED MULTIPLY-EXCITED MAGNETIC FIELD SYSTEMS Mesh Current Mesh Current-1 Moving Iron Instruments Multiplexing Network Theorems Node Voltage Method On-No Load And On Load Condition PLC PORT EXTENDER POTIER & ASA METHOD POWER TRANSFORMER POWER TRANSFORMER TESTING POWER TRANSFORMER TESTING METHODS PROGRAMMABLE LOGIC PROGRAMMABLE LOGIC CONTROLLER Parallel Port EXPANDER Paschen's law Piezoelectric Wave-Propagation Transducers Potential Transformer RADIO INTERFERENCE RECTIFIERS REGULATION OF ALTERNATOR REGULATION OF THREE PHASE ALTERNATOR Read a Capacitor SINGLY-EXCITED SOLIDS AND LIQUIDS Classical gas laws Secondary effects Semiconductor strain gages Speaker Driver Strain Gages Streamer theory Superposition Superposition theorem Swinburne’s Test TMOD TRANSFORMER TESTING METHODS Tape Recorder Three-Phase Wattmeter Transformer Tap Changer Transformer Testing Vector group test Virus Activity Voltage Insulator Coating Voltage To Frequency Converter Voltage to current converter What is analog-to-digital conversion Windows work for Nokia capacitor labels excitation current test magnetic balance voltage to frequency converter wiki electronic frequency converter testing voltage with a multimeter 50 hz voltages voltmeter

Search More Posts

Followers