The major parts of diesel engines

Chapter The major parts of diesel engines Content of chapter consist of: 2.1 Classification rules on diesel construction 2.2 Static parts 2.3 Moving parts 2.4 Driving mechanisms 2.5 Indicate components 05/14/16 Editor: Nguyen Trung Cuong engine 2.1 Classification rules on diesel engine construction • • • • • The construction of diesel engine can be classified as follows: Main static parts, Moving parts, Driving mechanisms, Indicate component, Control and safety devices 05/14/16 Editor: Nguyen Trung Cuo ng 2.2 Static parts The main static parts of the diesel engines consist of the following ones: • Bedplate • Engine frame (framework) • Cylinder block • Cylinder liners • and Cylinder covers 05/14/16 Editor: Nguyen Trung Cuo ng 2.2 Static parts a Bedplate • The bedplate is the foundation of an engine 05/14/16 Editor: Nguyen Trung Cuo ng 2.2 Static parts a Bedplate • Main bearings serve as supports for the crankshaft 05/14/16 Editor: Nguyen Trung Cuo ng 2.2 Static parts a Bedplate • Each bearing comprises a housing cap and two cylindrical shells 05/14/16 Editor: Nguyen Trung Cuo ng 2.2 Static parts a Bedplate • The bedplate serves to fasten an engine to the body, to support the entire weight of fixed parts, 05/14/16 Editor: Nguyen Trung Cuo ng 2.2 Static parts a Bedplate • • To receive the forces transmitted from the moving parts; And to form the oil basin for circulating oil 05/14/16 Editor: Nguyen Trung Cuo ng 2.2 Static parts b Engine frame • • • • The boxlike framework connects the cylinder block with the bedplate and forms the oil-tight crankcase It is subjected to the compressive force caused by the weight of the cylinder, Supports the tensile force exerted by the cylinder at the time of explosion and The thrust due to tilting of the 05/14/16 connecting rod Editor: Nguyen Trung Cuo ng 2.2 Static parts c Cylinder block • • • The high speed marine diesels engine are built on the "monoblock" principle, Their major static component is a single piece cast block, Which are cast and bored with individual cylinders 05/14/16 Editor: Nguyen Trung Cuo ng 10 2.3.1 Piston and it's components c Piston rings: • Scraper edges remove the excess oil on the downward stroke and distribute the oil on the upward stroke 05/14/16 Editor: Nguyen Trung Cuo ng 30 2.3.2 Connecting rods and cross-heads a Connecting rods • The connecting rods converts the rectilinear motion of the trunk piston or cross-head in to the rotary motion of the crankshaft 05/14/16 Editor: Nguyen Trung Cuo ng 31 2.3.2 Connecting rods and crossheads a Connecting rods • Lubricating oil to the smaller end is fed from the larger end through the copper tube or a hole provided along the trunk of the connecting rods L.O to piston pin L.O from main pipe 05/14/16 Editor: Nguyen Trung Cuo ng 32 2.3.2 Connecting rods and cross-heads b Cross-heads    The cross-head often found in large, low speed engines The piston and piston rod moves only in the vertical direction, There is no side thrust, so the piston need not have an extended trunk area to absorb the thrust 05/14/16 Editor: Nguyen Trung Cuo ng 33 2.3.2 Connecting rods and cross-heads b Cross-heads  There are, however, crosshead guides to take the side thrust, which results from the angularity of the connecting rod to crankshaft motion 05/14/16 Editor: Nguyen Trung Cuo ng 34 2.3.2 Connecting rods and cross-heads b Cross-heads   The cross-head guides are supported by the framework of the engine The structure consists of a guide shoe and a slide guide The lower end of the piston rod is fastened to the crosshead with nut 05/14/16 Editor: Nguyen Trung Cuo ng 35 2.3.3 Crankshaft a Acting force and materials:    The crankshafts are subjected to bending and torsional action during engine operation and These alternately changing forces exert complex and repetitive stress Forged steel is normally used to make crankshafts and nickchrome steel is used for highspeed engine to ensure durability 05/14/16 Editor: Nguyen Trung CuoPosition36 of crankshaft ng 2.3.3 Crankshaft b Arrangement: Arrangement and firing order of crankshaft: Cranks in the multi-cylinder engine are arranged so that the backward movement is uniform by compensating for centrifugal force and irregular movement of moving parts 05/14/16 Editor: Nguyen Trung Cuong 37 2.3.3 Crankshaft C Supply lubricating oil to the crankshaft   Lubricating oil flows from the main pipe to the main bearing, Through drilled hole continuously to the connecting rod and piston pin L.O to piston pin L.O from main pipe 05/14/16 Editor: Nguyen Trung Cuo ng 38 2.3.3 Crankshaft crankshaft of the multi-cylinder engine 05/14/16 Editor: Nguyen Trung Cuong 39 2.3.3 Crankshaft d Counter weight (counter-balance): Counter weights are designed to minimize engine vibration by balancing the centrifugal force of the webs and pins, produced by the rotation of the crankshaft 05/14/16 Editor: Nguyen Trung Cuong 40 2.3.3 Crankshaft d Counter weight (counter-balance): Also, due to the inertia effect of counter weights the size of the flywheel can be reduced 05/14/16 Editor: Nguyen Trung Cuong 41 2.4 Driving machanism     The fundamental roles the driving mechanism plays are: To control the process of charging fresh air into the cylinder, Discharging the combustion products out of the cylinder and Supplying fuel oil into the combustion chamber 05/14/16 Editor: Nguyen Trung Cuo ng 42 2.4 Driving machanism   • • The camshaft is driven by vertical shaft, chain or driving gear The speed ratio of the crankshaft to the camshaft is 1:1 in the two stroke engine and 2:1 in the four stroke engine 05/14/16 Editor: Nguyen Trung Cuo ng 43 1) 2) 05/14/16 What is function of the piston ring and oil ring Why is the cross-head type piston longer than trunk type piston Editor: Nguyen Trung Cuong 44 [...]... Moving parts The main moving parts of the diesel engines consist of the following ones: • Piston and it's components • Connecting rod and crosshead • Crankshaft 05/14/16 Editor: Nguyen Trung Cuo ng 19 2.3.1 Piston and it's components a Piston • There are two types of pistons: trunk type and cross-head type: The trunk piston is used in engines where the connecting rod goes directly from the piston to the. .. pressure So it is provided with passage of cooling water 05/14/16 Editor: Nguyen Trung Cuo ng 12 2.2 Static parts d cylinder covers • • • • • • The design of a cylinder cover depends upon such factors as: the size of the valves, The size of fuel injection valve, the size of cylinder, and the shape of the combustion chamber 05/14/16 Editor: Nguyen Trung Cuo ng 13 2.2 Static parts d cylinder covers 05/14/16... Static parts c Cylinder block • • • The cylinder of low speed diesel engines is an independent unit The structure of cylinder blocks of two stroke engines is more complicated than that of four stroke engines Because they must have passage for scavenging air and exhaust gases.Editor: Nguyen Trung Cuo 05/14/16 ng 11 2.2 Static parts d cylinder covers • • • The cylinder covers, which forms a part of combustion... it's components a Piston • • • The cross-head type piston has guides to absorb the thrust of the connecting rod And their sufficient lubrication decrease the mechanical friction Thus, the uneven wear of the liner is avoided 05/14/16 Editor: Nguyen Trung Cuo ng 21 2.3.1 Piston and it's components b Piston pins: • The piston pin withstands, in spite of its sliding speed, the highest bearing pressure within... Lubricating oil to the smaller end is fed from the larger end through the copper tube or a hole provided along the trunk of the connecting rods L.O to piston pin L.O from main pipe 05/14/16 Editor: Nguyen Trung Cuo ng 32 2.3.2 Connecting rods and cross-heads b Cross-heads    The cross-head often found in large, low speed engines The piston and piston rod moves only in the vertical direction, There is no... it's components c Piston rings: • Scraper edges remove the excess oil on the downward stroke and distribute the oil on the upward stroke 05/14/16 Editor: Nguyen Trung Cuo ng 30 2.3.2 Connecting rods and cross-heads a Connecting rods • The connecting rods converts the rectilinear motion of the trunk piston or cross-head in to the rotary motion of the crankshaft 05/14/16 Editor: Nguyen Trung Cuo ng 31... cross-head guides are supported by the framework of the engine The structure consists of a guide shoe and a slide guide The lower end of the piston rod is fastened to the crosshead with nut 05/14/16 Editor: Nguyen Trung Cuo ng 35 2.3.3 Crankshaft a Acting force and materials:    The crankshafts are subjected to bending and torsional action during engine operation and These alternately changing forces... Trung Cuong 16 2.2 Static parts d cylinder covers • • The cylinder cover is cooled with water, Usually fresh water, which is fed into the cooling space through the outer pipe 05/14/16 Editor: Nguyen Trung Cuo ng 17 2.2 Static parts d cylinder covers • • • The water outlet pipe is mounted at the highest point on the cover For preventing air pocket forming inside the cooling space The air pocket probably... Editor: Nguyen Trung Cuong 14 2.2 Static parts d cylinder covers • The cylinder cover of two stroke engine with exhaust valve, scavenge port is similar to that of a four-stroke engine 05/14/16 Editor: Nguyen Trung Cuo ng 15 2.2 Static parts d cylinder covers • The cylinder covers of return loop scavenge two-stroke engines are provided with sleeves only for the injection and starting valves 05/14/16... so the piston need not have an extended trunk area to absorb the thrust 05/14/16 Editor: Nguyen Trung Cuo ng 33 2.3.2 Connecting rods and cross-heads b Cross-heads  There are, however, crosshead guides to take the side thrust, which results from the angularity of the connecting rod to crankshaft motion 05/14/16 Editor: Nguyen Trung Cuo ng 34 2.3.2 Connecting rods and cross-heads b Cross-heads   The