Tài liệu sữa chữa động cơ D19TCIE3- THACO FRONTIER TF2800 Tài liệu sữa chữa động cơ D19TCIE3- THACO FRONTIER TF2800Tài liệu sữa chữa động cơ D19TCIE3- THACO FRONTIER TF2800Tài liệu sữa chữa động cơ D19TCIE3- THACO FRONTIER TF2800Tài liệu sữa chữa động cơ D19TCIE3- THACO FRONTIER TF2800Tài liệu sữa chữa động cơ D19TCIE3- THACO FRONTIER TF2800Tài liệu sữa chữa động cơ D19TCIE3- THACO FRONTIER TF2800
Main Technical Specifications and Data
Main technical specifications
Type In-line, water-cooled, four-stroke, supercharged and mid-cooling, high-pressure common rail Number of cylinders × diameter × stroke 4×81×97
Cylinder sleeve type No cylinder sleeve
Combustion chamber type Direct injection
Air-breathing mode Supercharged and mid-cooling
Rated power / speed kW/r/min 93/3200
Minimum fuel consumption rate g/kWãh ≤205
Working sequence of each cylinder 1-3-4-2
Crankshaft rotation direction Clockwise (from the front of diesel engine)
Lubrication mode Pressure-spatter mixing
Cooling mode Forced circulation water cooling type
Aftertreatment DOC+DPF+SCR+ASC
Specifications of main accessories
Name of accessories Specification of accessories
Type High-pressure common-rail pump
Fuel injector Type Electronically controlled
Diesel filter Type Paper filter-element rotation type
Type Paper filter-element rotation type
Oil filter Type Filter element type
Rated flow The flow is 200L / min and the lift is 15m at water temperature of 80℃ and speed of 6680rpm
Oil pump Type Rotor pump
Rated flow ≥70L/min(at 3200r/min)
Model and specification QDJ2581(24V/3.7kW)
Temperature Opening temperature :78±2℃; full-opening temperature: 92℃
Accessory belt Type 6PK poly V-belt
Technical parameters of main parts of electric control system Table 3
Atmospheric pressure measurement range kPa 50 ～ 115
Working clearance of sensor mm 0.5～1.5
Working clearance of sensor mm 0.3～1.0
Maximum axial force of installation kN 21 Working voltage of rail pressure sensor V 5±0.25
Voltage of water level sensor V 24
Resistance of water level sensor kΩ 560±5.6 Pressure difference between inlet and outlet of filter element kPa 10(at rated flow)
Pressure difference between inlet and outlet of filter element kPa 15(at rated flow) Filtration accuracy and efficiency 3～5μm；≥95.5％
Oil supply per cycle mm 3
Rotation direction Clockwise (from the front) Fuel injector
Flow cm 3 (at 10MPa pressure,30s)
Main technical data
1 Valve timing (based on crank angle) Table 4
Opening of intake valve (before TDC) 32.8°
Closing of intake valve (after BDC) 47.2°
Opening of exhaust valve (before BDC) 41.3°
Closing of exhaust valve (after TDC) 30.7°
2 Various temperature and pressure ranges of diesel engine Table 5
Discharge temperature at 15 min power ≤ 750℃
Oil temperature under declared working condition ≤ 120℃ Outlet water temperature of cooling water under declared working condition ≤ 95℃
Oil pressure at the lowest idle speed ≥ 100kPa
3 Tightening torque of main bolts Table 6
The tightening specifications for various engine components are crucial for optimal performance The main bearing bolt, designated M11×1.5-10.9, requires a torque of 50 Nm followed by a rotation of 120 degrees For the connecting rod bolt, M9×1-10.9, the specified torque is 30 Nm with an additional rotation of 120 degrees The flywheel bolt, M10×1-10.9, should be tightened to 40 Nm and then rotated 90 degrees Lastly, the cylinder head bolt (KAMAX), M12×1.5-10.9, demands a torque of 50 Nm and a rotation of 270 degrees.
Mounting bolt for camshaft cover M6 11～15
Mounting screw for fuel pump flange M8 22～29
Gland nut for fuel pump shaft end M18×1.5 85~90
Camshaft sprocket bolt M12×1.5-10.9 Rotation angle method 80Nm+45°
Bolt for moving rail and fixed rail of chain M8 22～28
Tensioner of fuel pump chain M22x1.5 60
Fixing bolt of chain cover M6 10～14
Drain plug of oil pan M14×1.5 35~45
Fixing bolt of fuel rail M8 22～29
Union nut of fuel rail end M14×1.5 26～30
Union nut of fuel pump end M16×1 33～37
Union nut of fuel injector end M14x1.5 20~24
Compression bolt of pressing plate of fuel injector M8-10.9 34～38
Bolt of oil inlet of supercharger M10×1.5 20~28
Bolt of oil inlet of supercharger M12 32~40
Fixing bolt of generator bracket M10 43~47
Bolt of automatic tensioning wheel M10 40 ～ 50
Bolt of fan connecting shaft M8 23～27
Valve deflection of new engine 0.85~1.15 mm
The length of the nozzle head extending out of the bottom plane of the cylinder head 2~2.7mm
Clearance between crankshaft position sensor and signal tooth 0.5~1.5mm Clearance between camshaft position sensor and signal tooth 0.3~1.0mm
5 Tightening torque of common bolts and nuts (for reference) Table 8 Bolt strength grade
Nominal diameter of bolt mm
Size, fit clearance and wear limit of main parts
No Name of parts Fit dimension mm
1 Inner diameter of cylinder hole φ81( 0 0 01 ) 0.0775～
Outer diameter of piston skirt φ80.915±0.0075
Outer diameter of piston pin φ30 ( 0 0 005 )
Bushing hole of connecting rod small end φ30( 0.033 0.02 )
0.02～0.038 0.08 Outer diameter of piston pin φ30( 0 0 005 )
Main bearing bush hole of crankshaft φ60 ( +0.069 +0.03 )
Bearing bush hole of connecting rod φ50 ( 0.034 0.018 )
0.018～0.053 0.15 Connecting rod journal of crankshaft φ50 ( 0 0 019 )
6 Opening clearance of the first piston ring 0.2 ～ 0.35 0.8
7 Opening clearance of the second piston ring 0.5～0.70 1.0
8 Opening clearance of the third piston ring 0.25～0.50 1.0
11 Axial clearance of connecting rod big end +0.35～+0.63 1.0
13 Axial clearance of intake camshaft 0.07 ～ 0.202 0.3
14 Axial clearance of exhaust camshaft 0.07 ～ 0.202 0.3
0.006～0.035 0.07 Outer diameter of hydraulic tappet φ12 ( 0 0 011 )
18 Thickness of inner and outer rotors of oil pump 25 ( 0 0 02 ) 0.03~0.08 0.15
Depth of inner cavity of oil pump cover 25 ( 0.06 0.03 )
19 Meshing clearance between idler gear and crankshaft gear 0.2~0.3 0.45
20 Meshing clearance between idler gear and blast pump gear 0.2~0.3 0.45
Disassembly
Maintenance requirements and precautions of engine
1 Non professional maintenance personnel shall not dismantle and repair the engine arbitrarily The customer should ask the dealer or Yunnei special service station for repair
2 The operator shall be familiar with the structure, technical data, parts assembly relationship and technical dismounting requirements of the diesel engine, and master the correct disassembly and assembly method and use methods of maintenance tools
If the user does not have the necessary technical conditions, please contact Yunnei special service station
3 The disassembly sequence is generally from the outside to the inside, from the assembly to the parts In order to improve the assembly efficiency and ensure the correctness of the assembly, it is necessary to check marks and mark during disassembly The removed parts shall be cleaned and inspected carefully The parts that can be reused shall be stored by category according to the assembly The precision parts shall be separated from the general parts and stored in clean containers
4 The assembly sequence is generally from inside to outside, following the principle of first assembling parts into assembly units, then assembling assembly units into assemblies During assembly, pay attention to the installation dimension, orientation, fit clearance, tightening torque, etc., and avoid missing of parts, wrong fitting, scratching the fitting surface of parts and foreign matters falling into the engine Proper spanner shall be used for assembling bolts and nuts, and the force shall be even and appropriate Use the appropriate cotter pin, spring washer, etc for locking In addition, pay attention to checking the part label and assembly mark to ensure the correct position and movement relationship between parts
5 Ensure that the diesel engine is always in a clean and complete state Before disassembling and assembling parts, the parts shall be cleaned to ensure the assembly quality The complex adjustment and maintenance should be carried out indoors to prevent the inside of diesel engine being polluted
6 The engine adopts Bosch electronic-control high-voltage common-rail system The negative pole must be used for battery bonding and the positive pole must be controlled by the main power switch of the whole vehicle The main power switch must be disconnected during maintenance to prevent damage to ECU The components of electronic control system shall not be immersed in water or drenched by rain, and each sensor shall not bear impact and gravity
7 Look out during maintenance or disassembly and assembly to prevent bumping, crushing, or personal injuries caused by improper use of tools
8 The quality parts shall be used for the replacement.
Disassembly of engine assembly
When removing the engine from a vehicle, it is essential to separate it from the transmission Alternatively, the engine and transmission can be lifted out together after disconnecting all transmission connections.
Turn the ignition switch to the LOCK position and disconnect the negative battery cable
Unscrew the drain plug on the oil pan, drain the oil, and collect it
Dismantle the inlet and outlet hose of the engine and drain the coolant
Dismantle the power connection wires of generator, starter, connectors of sensors, and oil temperature and water temperature sensors
Disassemble the fuel pipeline and pull out the fuel inlet pipe and return pipe
Dismantle the air intake pipe and the connecting hose of air filter
Release the radiator bracket and take out the radiator, intercooler and air shield as a whole
For the engine with vacuum booster, steering pump, air conditioner or blast pump, disconnect the corresponding connecting pipeline
Release the connection between the tailpipe and the aftertreatment pipeline
Loosen the connecting bolts between the engine and the transmission to separate the transmission from the engine
Loosen the fixing bolts of the front bracket of the engine, and hang the front and rear lifting eyes of the engine with slings to lift it down smoothly.
Disassembly of engine assemblies
1 Disassembly of fan and belt
1 Silicone oil clutch fan assembly
To remove the poly V-belt, utilize a 13mm square wrench to engage the groove on the automatic tensioning wheel and turn it anticlockwise After removal, refrain from cleaning the belt with water or gasoline, and ensure that no oil is applied to the belt to prevent slipping.
2 Removal of outer pipeline of front-end generator support
1 Weldment of water inlet pipe of heater 4 PFM seat-connecting hose of throttle
2 PFM sensor seat support 5.Electronic throttle body
3.PFM sensor seat 6.Throttle body gasket
When the PFM sensor seat is disassembled, the PFM sensor can be removed together without disassembly
3 Removal of front-end gear train component
2 Generator support 7 Fan support assembly
3 Generator support frame 8 Idler assembly 2
4 Automatic tensioning wheel assembly 9.Starter
The bolts on idler assembly 1 are left-hand bolts, whose direction of turning is opposite to that of bolts of other components
1 Front lifting lug 6.Hinged bolt M14 (30ãm) 11.Vacuum rubber tube
7 Return hose of air compressor (with ball joint)
9.Water inlet hose of air compressor
5.Air conditioner bracket 10 Air compressor assembly (with gear)
When disassembling the air compressor, temporarily set aside the oil inlet pipe assembly, which will be removed later along with the cooling water pipe Only the hinged bolt should be detached at this stage.
1 EGR water outlet hose 9 EGR pipe gasket 2
2 EGR water inlet hose 10 EGR valve
3 EGR exhaust temperature sensor 11 EGR valve gasket
4 Vacuum hose 12 EGR air inlet pipe
5 EGR escape pipe 13 EGRpipe gasket 1
7 EGR mixing pipe 15 EGR by-pass control valve
To remove the EGR air inlet pipe, simply loosen the bolts on the rear cover plate of the cylinder head, as it will be taken out later along with the EGR cooler.
When the EGR is removed, it is unnecessary to remove the EGR valve, water inlet hose and water outlet hose They can be removed together with the EGR cooler
1 Weldment of large-circulation water outlet pipe 10.Union pipe gasket of water outlet of cylinder head
2 Weldment of water inlet pipe for heater 11 Water return hose
3 Water inlet hose for heater 12 SCR water return pipe weldment
4 Engine cooling – large-circulation hose 13 SCR water return hose
5 Small-circulation steel pipe weldment 14 Small-circulation pipe weldment
6 Oil inlet pipe assembly of air compressor 15 Water return pipe weldment
7 Small-circulation by-pass pipe 16 Water pump assembly
8 Small-circulation water return hose 17 Water pump gasket
9 Water outlet union pipe of cylinder head
The welding parts of the water inlet pipe of the heater have been removed with the generator bracket at first
The water inlet hose of heater can be removed together with the large-circulation water outlet pipe
The oil inlet pipe assembly of air compressor needs to be removed after the small-circulation steel pipe weldment
If not necessary, the water outlet union pipe of the cylinder head can not be disassembled and kept on the cylinder head assembly
The small-circulation pipe weldment and water return pipe weldment can be removed along with the water pump if they are not needed However, if disassembly is required, it is important to take care of the O-ring near the water pump to avoid damage or loss.
6 Disassembly of fuel injection system
1 Oil return pipe assembly of fuel injector
2 High pressure oil pipe from cylinder 1 to cylinder 4
3 Pressing plate bolt of fuel injector
7 High pressure oil pipe from pump to rail
9 Lubricating pipe assembly of high-pressure oil pump
16 Mounting screw of high pressure pump (22-29N.m)
17 High pressure pump Key points for disassembly:
Push open the spring locking clip of oil return pipe of fuel injector, and then pull out the oil return pipe of fuel injector
For removing the high-pressure oil pipe, use a wrench to clamp the joint on the fuel injector and high-pressure oil pump to prevent the joint from loosening
For disassembling the fuel injector, protect the copper gasket and O-ring of the fuel injector from damage or loss
To remove the fuel return pipe, first loosen the bolts on the engine oil module cover and one fixing nut on the air inlet pipe The oil return hose can then be detached along with the oil return pipe.
For removing the fuel inlet pipe, loosen one bolt of the cylinder block The fuel inlet hose and pipe joint can be removed together with the fuel inlet pipe
To ensure cleanliness at all oil inlets and outlets, it is essential to install protective caps on the oil inlet and outlet joints of the fuel rail, injector, high-pressure oil pump, and oil return pipe of the injection pump.
When disassembling the fuel injection pump along with the timing linkage, ensure that the connection is not overly tight If necessary, gently tap the high-pressure oil pump shaft with a copper rod, taking care not to damage the thread at the shaft's end Additionally, protect the O-ring of the high-pressure oil pump from any damage or loss during the process.
7 Removal of oil pan, chain cover, and valve cage cover
2 Rubber gasket of valve cage cover
12 Pressing plate of torsional shock absorber
17 Chain cover gasket Key points for disassembly:
The dipstick and dipstick sleeve are removed together with the water pump
The oil pan, valve cage cover and shock absorber assembly must be removed before removing the chain cover
To properly remove the bolts of the torsional shock absorber, it is essential to secure the rear end of the crankshaft This can be achieved by screwing one bolt into each side of the flywheel assembly and using a tool bar to clamp it in place.
Avoid damaging the front oil seal installed on the chain cover
Generally, the oil-gas separator assembly, oil filler cover and camshaft position sensor need not be disassembled separately;they can be removed together with the valve cage cover
8 Removal of chain timing system
7 Fuel pump sprocket nut (85Nm)
Use special tools to clamp the intake and exhaust camshaft before removal of camshaft sprocket bolts
Before removing the camshaft chain tensioner, ensure to press the hydraulic tensioner tappet back to its original position To prevent the plunger from popping out during disassembly, use a fixed pin to clamp the tensioner's plunger securely.
2 Cam bearing cover bolt (13N) 6 Rocker arm assembly
3 Cam bearing cover 7 Hydraulic tappet
4 Exhaust camshaft 8 Cylinder head bolt (120~205Nm)
After the cam bearing cover, rocker arm assembly and hydraulic tappet are removed, they shall be placed in order
The glow plug must be removed to prevent damage such as bumping or breaking caused by placing the cylinder head
Use the torque wrench to remove the cylinder head bolts in the specified sequence
The valve, valve spring, etc do not need to be disassembled; they can be removed together with the cylinder head assembly
When the cylinder head assembly is removed, the air inlet pipe, air inlet union pipe, exhaust pipe, supercharger, tail pipe, etc do not need to be removed
If they need to be disassembled, follow the steps below:
1 Weldment of oil return pipe of supercharger
2 Flange gasket 2 of supercharger oil return pipe
3 Flange gasket of supercharger oil return pipe
4 Supercharger oil inlet pipe bolt
5 Supercharger oil inlet pipe bolt 2
12 Protective cover bolt of exhaust pipe
13 Flat gasket of protective cover bolt of exhaust pipe
17 Cover plate of supercharger oil return port
18 Flange gasket of supercharger oil return pipe
The specification of hollow bolts at both ends of oil inlet pipe of supercharger is different, which needs to be distinguished
The cover plate of oil return pipe of supercharger can not be disassembled temporarily; it can be removed together with the cylinder block
11 Removal of air inlet pipe
1 Air inlet union pipe 3 Air inlet pipe
2 Gasket of air inlet union pipe 4 Gasket of air inlet pipe
After removing the air inlet, exhaust, and glow plug, and ensuring there are no other connections to the engine body, lift the cylinder head assembly using the lifting lug, making sure the front lifting lug is properly installed along with the steering pump bracket.
12 Removal of oil cooler and oil suction pan
1 Engine cooling water outlet union pipe
2 Gasket of engine cooling water outlet union pipe
6 Main shaft nut of oil pump
8 Oil pump inner rotor and main shaft assembly
10 Plug screw of pressure regulating valve of oil pump
12 Guide post of pressure regulating valve spring
If the cylinder block is not replaced, the oil pump, pressure regulating valve, etc do not need to be removed
13 Removal of clutch and flywheel
1 Clutch and pressure plate assembly
3 Flywheel bolt (85 ~ 125Nãm for disassembly)
The input shaft bearing and crankshaft assembly are joined through an interference fit, allowing for their removal as a single unit if separate disassembly is unnecessary.
Make assembly marks on the clutch and flywheel to maintain the dynamic balance of the crankshaft after reassembly
Note: only when the crankshaft needs to be replaced can the clutch assembly and flywheel be removed
1 Flywheel housing 5 Idler gear shaft
2 Rear oil seal 6 Rear gear housing
3 Retainer ring weldment of idler gear 7 Flywheel housing gasket
4 Idler gear assembly 8 Gear housing gasket
The flywheel housing is equipped with a rear oil seal, which shall not be damaged during disassembly
The idler gear shaft and rear gear housing are joined through an interference fit, allowing for their removal as a single unit along with the gear housing when separate disassembly is unnecessary.
15 Removal of piston rod unit
1 Connecting rod bolt (65~100Nãm) 8 Composite oil ring
2 Connecting rod cap 9 Retainer ring
3.Lower bearing shell of connecting rod 10 Piston pin
5 Upper bearing shell of connecting rod 12 Connecting rod bush
6 First gas ring 13 Connecting rod body
To disassemble the connecting rod assembly, first use a torque wrench to remove the connecting rod bolts and take off the connecting rod bearing cap, ensuring the crankshaft is turned for easier removal Carefully pull the piston rod unit out of the cylinder towards the cylinder head, while being mindful of the alignment between the connecting rod and the connecting rod cap to avoid pulling them out of order.
To begin the disassembly process, carefully remove the first and second gas rings along with the third composite oil ring Utilize clip forceps to detach the retainer ring of the piston pin, then gently push out the piston pin to remove the connecting rod assembly Ensure that the markings on the piston and connecting rod assembly correspond with the cylinder number for proper alignment.
1 Main bearing bolt (95 ~ 140Nãm) 5 Crankshaft thrust plate
2 Main bearing cap 6 Main shaft bushing (upper)
3 Main shaft bushing (lower) 7 Piston cooling nozzle component
To properly disassemble the engine, utilize a torque wrench to remove the main bearing bolts in the correct sequence Carefully take off the main bearing cover and thrust plate, followed by the crankshaft Before removal, ensure to check the axial clearance of the crankshaft and replace it if it exceeds the specified limits.
Assembly
Assembly of piston cooling nozzle, crankshaft, flywheel and clutch assembly
Check whether there is scratch on the engine body surface, and ensure the body is clean
Install piston cooling nozzle and chain nozzle; tightening torque: 10N.m (note: check whether the O-ring of cooling nozzle is missing or damaged, and replace it if any)
To install the upper main bearing bush with an oil groove, place it into the main bearing hole of the engine body, ensuring that the oil hole of the bearing bush aligns with the oil passage hole on the main bearing seat It is crucial to avoid reversing the upper and lower bearing bushes, as there is a slip groove on both the main bearing seat and cover that corresponds to the bearing bush Before installation, apply a small amount of clean lubricating oil, and do not use any metal or non-metal gaskets during the process.
To install the crankshaft in the engine body, ensure the main bearing seat hole is clean, particularly the oil hole, journal surface, and bearing seat surface Prior to installation, apply a small amount of lubricating oil to the upper bush of the main shaft, and after installation, lubricate the main journal.
Install the crankshaft thrust plate on the fourth main bearing seat; the grooved side of the thrust plate faces outwards, and it must not be installed reversely
To install the main bearing cap, follow the markings 1, 2, 3, 4, and 5, positioning it from the front (fan end) to the back (flywheel end) Ensure the arrow on the cap points forward and that the upper and lower positioning lips are aligned on the same side Once confirmed that the cap is aligned with the engine body's rabbet, gently tap it into place using a copper rod.
The main bearing bolts should be tightened symmetrically in two steps using the rotation angle method, starting from the middle and moving outward Initially, tighten the bolts to 30 ± 1.5 Nm, followed by a second tightening to 50 ± 2.5 Nm, and then rotate an additional 120° ± 5° The final monitoring torque should be between 95-140 Nm Prior to installation, a small amount of engine oil must be applied to the bolts After tightening, the crankshaft should rotate smoothly with an axial clearance of 0.09-0.24 mm It is important to note that the main bearing cap bolts can only be tightened a maximum of three times, as they are pre-tightened twice at the factory and must be replaced after one additional tightening.
After installation, the crankshaft shall rotate flexibly without jamming, and the axial clearance of crankshaft shall be checked.
Assembly of piston rod unit
The piston features a reentrant direct-injection ω-type combustion chamber, with the top face's arrow oriented towards the engine's front end during assembly Additionally, a wedge-shaped connecting rod is utilized to enhance the piston’s strength.
To install the copper bush into the connecting rod body, use an interference fit to press it in place, ensuring that the oil hole of the copper bush aligns with the oil hole of the connecting rod body Typically, the copper bush is pre-installed when purchased new.
Install the snap rings of piston pin on one side of the piston
To install the piston, place its inner cavity onto the connecting rod at room temperature, ensuring that the piston aligns with the pin hole of the connecting rod Insert the piston pin while making sure that the slip groove direction of the connecting rod's big end hole matches that of the piston, avoiding interference with the cooling nozzle.
Install the snap rings of piston pin on the other side
The piston is equipped with three rings, each requiring proper "opening clearance" after installation in the cylinder hole at normal temperature To measure this clearance, the piston ring can be placed in the cylinder hole of a new engine body and assessed using a thickness gauge The standard opening clearances are as follows: the first gas ring should measure between 0.25-0.35mm, the second gas ring between 0.50-0.70mm, and the oil ring between 0.25-0.50mm It is crucial to note that the wear limit for these rings is 1mm; exceeding this limit necessitates replacement.
To properly install piston rings, utilize a specialized tool to avoid damaging the piston surface Begin by installing the oil ring, ensuring its opening is positioned opposite the joint direction of the pushing-out ring, which should be placed in the piston ring groove first Next, install the second gas ring, followed by the first gas ring It is crucial to install the rings correctly, with the "TOP" marking facing the piston top Ensure that the openings of each ring are staggered by 120° from one another and aligned away from the pin hole direction Finally, confirm that the piston ring rotates freely within the groove.
Apply a small amount of oil to the piston ring, connecting rod bearing bush, piston pin, etc
To install the piston rod unit, utilize a specialized tool to ensure proper placement into the designated cylinder hole When disassembling, it is crucial to maintain the correct alignment with the cylinder and avoid mixing up the piston rod units during installation.
To install the connecting rod cap and bolt, first apply a small amount of lubricating oil to the bearing bush's working surface before screwing in the connecting rod bolt Tighten the bolts for each cylinder alternately in two steps: first to 15 ± 1.5 Nm, and then to 30 ± 2.5 Nm, followed by a continuous 120° ± 50 angle turn, ensuring the final monitoring torque is between 65-100 Nm Note that connecting rod bolts should not be tightened more than three times; since they are pre-tightened twice at the factory, they must be replaced after one additional tightening.
To maintain optimal engine performance, it is crucial to ensure the quality of the piston rod unit When replacing the connecting rod, the weight difference between the new piston rod assembly and the original assembly of the same diesel engine should not exceed 15g.
The connecting rod body and cap are processed together and feature matching marks to ensure correct installation It is crucial to avoid incorrect assembly After installation, there should be a clearance between the connecting rod's big end and the crankshaft, allowing for smooth and flexible rotation of the crankshaft.
Assembly of oil pump and pressure regulating valve
To install the oil pump, first coat the internal and external surfaces of the outer rotor with clean oil Next, position it onto the engine body’s mounting hole, ensuring that the inner rotor assembly shaft aligns with the engine body’s shaft hole Finally, attach the inner rotor shaft components to the outer rotor, ensuring that the inner rotor rotates smoothly after installation.
Align the two locating pins, install the oil pump cover and four bolts, and tighten the bolts to the specified torque in diagonal sequence
To install the pressure-regulating valve, sequentially insert the plunger, spring guide post, pressure regulating spring, and plug into the valve hole of the oil pump located at the bottom of the cylinder block, ensuring to tighten the plug securely.
Subassembly and assembly of cylinder head
Use a special tool to gently press the valve oil seal into the valve guide end (note: the oil seal must be pressed into place)
When installing valves, it is essential to apply oil to the inner wall of the valve guide for proper lubrication Each valve must be installed individually, ensuring a one-to-one match with the corresponding guide pipes, as incorrect installation is not permitted during engine repairs.
To install the valve spring and its upper seat into the cylinder head, align them according to the markings Use a valve spring compressor to compress the spring, then carefully install the locking clip with tweezers Gradually release the compressor to ensure the clip remains secure After installation, gently tap the valve rod end with a rubber hammer to verify the locking clip's position Finally, check that the valve sinking is within the acceptable range of 1.0 ± 0.15mm for a new engine.
To measure piston protrusion, first locate the top dead center of the piston Next, position the dial indicator at the piston’s highest point and measure the protrusion at both the front and back along the crankshaft's axis on the cylinder block The maximum reading from the dial indicator will determine the piston protrusion, which is essential for selecting the appropriate cylinder gasket.
Cylinder head gasket thickness(mm) Piston protrusion(mm)
Ensure that the bottom surface of the cylinder head and the top surface of the engine body are clean Verify that the cylinder head gasket is flat and that the interlayer of the gasket is free from any foreign materials.
To install the cylinder head, first place the selected cylinder head gasket and align the cylinder head with the pin bush, ensuring not to push or pull it to avoid damage Apply a suitable amount of clean oil to the threads of the cylinder head bolts before installation Tighten the bolts to the specified torque in a diagonal crossing pattern, starting from the middle and moving outward, using a two-step process In the initial step, tighten the bolts to the recommended torque.
The cylinder head bolts should initially be tightened to a torque of 50 ± 5 Nm In the second step, they must be rotated to an angle of 270° ± 5°, with a final monitoring torque ranging from 120 to 205 Nm It is important to note that these bolts can only be tightened a maximum of three times; since they have already been tightened twice at the factory, they must be replaced after one additional tightening.
To ensure proper installation, apply the correct amount of oil to the tappet hole of the cylinder head and the top of the valve rod before sequentially installing the hydraulic tappet assembly and roller rocker assembly.
To ensure proper installation, apply clean oil to the roller rocker and the lower seat of the camshaft before placing the intake and exhaust camshaft into the cylinder head, making sure that the TOP position of both camshafts is oriented upward.
To install the camshaft cover, ensure it is properly aligned with the pin bush, then gently tap it into place using a nylon rod After pre-tightening the cam bearing cover, tighten the camshaft cover bolts twice to the specified torque of 13 ± 1Nm, working from front to back.
To install the glow plug in the cylinder head, ensure it is securely tightened to the specified torque Both the glow plug and the threaded hole must be free of grease and oil, and the installation tools and work area should be kept clean Additionally, during installation, avoid any mechanical impact on the heating head of the glow plug and the supporting pipe.
Install the water temperature sensor and tighten it.
Assembly of water pump, oil pump, gear housing and flywheel housing
To install the small-circulation pipe weldment, align it with the water pump and attach the water return pipe assembly, securing it with one bolt tightened to 3-5 threads After installing the dipstick sleeve, re-tighten the bolt Prior to installation, ensure the O-ring is in good condition, and apply a small amount of lubricating oil to it if necessary.
To install the water pump, first secure the cylinder block with four double-screw bolts Next, place the water pump gasket and position the water pump unit onto the bolts, ensuring it is fastened tightly with four nuts.
To install the fuel pump, select the appropriate angle for the pump body and ensure the shaft remains horizontal while pushing the pump into place Secure the pump by installing and tightening the bolts to the specified torque Prior to installation, verify that the O-ring of the oil pump is in good condition, and apply a small amount of lubricating oil to the O-ring to facilitate assembly.
To assemble the gear housing, first, insert the positioning double-screw bolts into the screw holes on both sides of the rear end of the cylinder block Next, gently place the gear housing gasket onto the positioning pins and double-screw bolts Align the gear housing with the positioning pins and secure it in place by installing the fixing bolts, tightening them to the specified torque.
To ensure proper installation of the idler gear shaft, apply an appropriate amount of oil to the positioning shaft and the idler gear bushing before assembly Install the idler gear shaft onto the gear housing, followed by the welding parts of the idler gear retainer ring and the fixing bolts, tightening them to the specified torque After assembly, verify that the meshing between the idler gear and the rear end gear of the crankshaft is flexible and free from clamping stagnation, with the meshing clearance at the tooth side within the required range.
Use a special tool to press the crankshaft rear oil seal into the flywheel housing, and do not damage the oil seal lip
To properly install the flywheel housing, first position the gasket on the double-screw bolts and pin bushes on each side Align the flywheel housing with the positioning pin bush, secure it in place with the fixing bolts, and then remove the double-screw bolts.
Assembly of timing linkage and chain cover
Adjust the position of intake and exhaust camshaft to make their TOP face upward (i.e top dead center position of cylinder 1), and fix the camshaft firmly with special tooling
To install the high-pressure pump chain, first, turn the crankshaft anticlockwise 75° from the top dead center Align the chain with the inlayer teeth of the crankshaft and oil pump sprockets according to the marks, ensuring it fits with the fuel pump shaft and the front end of the crankshaft Verify that the small lug on the back of the crankshaft sprocket is properly seated in the corresponding groove at the front end of the crankshaft Finally, install the fuel pump nut and screw it in manually without tightening it at this stage.
To install the camshaft chain, position it on the outer teeth of both the camshaft sprocket and the oil pump sprocket, ensuring alignment with the intake and exhaust camshafts Carefully push the chain into place, then manually install the bolts of the camshaft sprocket without fully tightening them at this stage.
To ensure proper assembly, rotate the crankshaft clockwise to reach the top dead center and secure the rear end with special tooling Verify the alignment of the chain and sprocket marks, then tighten the camshaft sprocket bolt and fuel injection pump sprocket nut to the specified torque Assemble the guide rail and secure it by tightening the guide rail bolt to the required torque Finally, install the tensioner and tighten its bolt to the specified torque, then release the screw fixing the plunger to allow it to extend into the tension chain.
To install the oil pump, first place the oil pump chain onto the crankshaft sprocket and the oil pump sprocket, ensuring it aligns with the oil pump shaft Next, secure the oil pump sprocket nut and tighten it to the specified torque.
Subassembly of chain cover: press the front oil seal onto the chain cover with tooling, and do not damage the oil seal lip
To install the crankshaft woodruff key, gently tap it into place using a copper rod, and then clean any copper debris from the components with a non-woven cloth.
Gluing: the joint surface between chain cover and cylinder head, between chain cover and engine body should be clean, and glue the four joints with a glue gun
After securing the positioning double-screw bolts into the intake and exhaust screw holes, gently sleeve the chain cover gasket onto the bolts and pin bushes, ensuring a smooth installation on the engine Align the locating pin bush to properly position the chain cover, then install the fixing bolts and remove the double-screw bolts Prior to installation, verify that the glue line of the chain cover gasket is intact, and after installation, trim any excess material from the top and bottom of the gasket.
Align the shock absorber's key slot with the crankshaft's key and insert it Secure the pressing plate and bolt, initially tightening the shock absorber bolt to approximately 15 N.m, followed by a final tightening to 425 ± 25 N.m.
Take down the tooling fixing the camshaft and crankshaft, and check whether all chains and sprockets operate normally by turning clockwise
Install the crankshaft speed sensor onto the chain cover
Before installation, inspect all parts for bruises, oil stains, rust, and dirt; do not use any parts with bruises and clean any oil stains Ensure that the pistons of cylinder 1 and cylinder 4 are at top dead center to prevent camshaft rotation, and fix the crankshaft at top dead center before tightening the bolts of the crankshaft belt pulley The marked surfaces of the sprocket and guide rail should face outward, with the sprocket marks aligning with the chain marks After assembly, verify that all chains and sprockets operate smoothly without any jamming.
Assembly of valve cage cover, oil module assembly, oil pan, and flywheel assembly
To assemble the valve cage cover, first, place the rectangular rubber ring and O-ring into the fuel injector fulcrum plug Next, install the fuel injector oil seal, the oil seal for the fuel injector pressing plate bolt, and the seal ring for the fuel injector fulcrum bolt onto the valve cage cover Proceed to install the oil-gas separator assembly and tighten it to the specified torque Finally, install the seal ring of the valve cage cover, followed by the camshaft sensor and the oil filler cap, ensuring that the rubber gasket is intact and undamaged.
To ensure a proper seal, apply two strips of plane sealant, each measuring 2-3mm in width and 1mm in thickness, along the joint between the cam bearing cover I and the cylinder head, as well as on the outer ring, keeping the glue lines close together The length of the sealant strips should match the joint surface Within 5 minutes of applying the sealant, install the cylinder head cover onto the machined parts of the cylinder head Finally, tighten the bolts of the valve cage cover and fuel injector fulcrum to the specified torque, progressing from the front end to the back end in a step-by-step manner.
Install the front and rear lifting lugs, and the front lifting lug needs to be installed together with the steering pump support
Install the oil suction pan assembly and gasket Tighten the bolts at the oil pump to the specified torque, and then tighten the bolts at the bracket
Install the oil pan assembly and gasket, and tighten the bolts to the specified torque
Install the drain plug and tighten it to the specified torque
Install the oil module assembly on the cylinder block and tighten the bolts to the specified torque
Install the engine oil module cover and engine cooling water outlet pipe, and tighten the bolts to the specified torque
To install the flywheel assembly onto the rear end of the crankshaft, first clean the crankshaft flange and flywheel rabbet with a clean towel to remove any dirt Secure the flywheel bolts to a torque of 40 ± 2Nm, then rotate the flywheel 90° ± 5° for a final monitoring torque of 85-125Nm.
Install the clutch driven plate, clutch pressure plate and cover assembly
The crankshaft, flywheel, and clutch assembly are dynamically balanced prior to delivery and must be reassembled according to the disassembly marks It is essential to ensure that the end surfaces of the flywheel and clutch pressure plate are free from oil stains and foreign contaminants.
The clutch pressure plate and cover assembly have been carefully adjusted before delivery, and need to be carefully adjusted after dismounting.
Installation of intake and exhaust system and fuel system
Check whether the O-ring and sealing copper gasket on the fuel injector are in good condition
To prevent air leakage, replace the sealing copper gasket after removal Ensure the injector mounting hole on the cylinder head is clean, particularly the contact surface with the gasket, free from impurities or foreign materials Protect the oil pipe joints on the fuel injector, high-pressure fuel rail, and fuel injection pump from dust and debris Do not remove the protective caps from the high-pressure oil pipe before installation.
To install the fuel injector, first remove the protective sleeve from the nozzle Then, carefully place the fuel injector with its sealing gasket, pressing plate, spherical washer, and bolt in the correct cylinder sequence, ensuring to pre-tighten the bolts by hand Take care not to damage the injection hole, and make sure the copper washer remains in place while preventing the O-ring from being crushed.
To install the high-pressure fuel rail, secure it to the two left screw holes on the cylinder head, tightening the fixing bolts to a torque of 25 ± 2 Nm Ensure that the harness plug of the high-pressure fuel rail is oriented towards the engine's flywheel housing.
To begin the installation process, remove the high-pressure joint of the fuel injector along with the protective caps from the high-pressure joint on the fuel rail and the high-pressure oil pipe for cylinders 1-4 Next, attach the four fuel rails to the corresponding high-pressure oil pipes of the fuel injectors, ensuring that the numbered end of each pipe aligns with the fuel rail to avoid reverse installation Once confirmed, hand-tighten the nuts at both ends of the high-pressure oil pipes and pre-tighten them to a torque of 3 ± 1 Nm.
Install the air inlet pipe stud to the cylinder head, install the air inlet pipe and gasket, and tighten the nuts to 10 ± 2Nm
Install the intake air temperature sensor onto the air inlet pipe
To begin the installation process, remove the high-pressure joint of the oil pump along with the protective caps from the high-pressure joint on the fuel rail and the high-pressure oil pipe Next, install the high-pressure oil pipe to the pump and fuel rail, ensuring to pre-tighten the nuts on the fuel rail and fuel injector side to a torque of 3 ± 1Nm by hand Finally, secure the oil pipe bracket by tightening the fixing bolts to the specified torque of 10 ± 2Nm.
Tighten the high-pressure oil pipe nuts at the fuel injector side one by one to 22 ± 2Nm
Tighten the nuts of high-pressure oil pipe at the fuel rail side one by one to 28 ± 2Nm
Tighten the high pressure oil pipe nuts of pump/rail at the oil pump side to 35 ± 2Nm
Install the fuel injector return pipe assembly
Install the fuel inlet pipe assembly Tighten M8 bolts connecting the fuel return pipe with the engine body to 25 ± 2Nm
Install the fuel return pipe assembly Tighten M6 bolts connecting the fuel inlet pipe with the air inlet pipe to 10 ± 2Nm
Install the lubricating oil pipe assembly of high pressure oil pump
Install the air inlet union pipe and electronic throttle
When installing the exhaust pipe, exhaust pipe heat shield, supercharger, and tail pipe, it is crucial to prevent any foreign objects from entering the air inlet and exhaust pipe to protect the diesel engine from potential damage.
Install the oil inlet pipe of supercharger
Install the engine wiring harness.
Cooling system
Install the drain valve assembly to the screw hole at the bottom of water jacket on the exhaust side of cylinder block
Install the water outlet union pipe of cylinder head, and the tightening torque of the bolt at the connection between the union pipe and the cylinder head is 10 ± 2Nm
Install the small-circulation steel pipe weldment and SCR water return pipe weldment, and the tightening torque of bolt is 25 ± 2Nm
Install the large-circulation water outlet pipe weldment and rubber pipe
To install the water inlet pipe weldment of the heater, it should be connected with the generator's lower bracket and the PFM sensor base bracket Initially, tighten two bolts manually, and then secure them firmly during the final assembly of the accessories.
For water pipe installation, it is essential to pre-assemble the rubber and water pipes into general assemblies, ensuring that clamps are applied to the rubber pipes as needed After the installation process, it is crucial to verify that the rubber pipes remain undistorted.
EGR system assembly
To pre-install the EGR cooler, first remove the EGR air inlet pipe, EGR valve, EGR upstream temperature sensor, and the rubber pipes for the EGR water inlet and outlet, along with the gasket Next, assemble these components onto the EGR cooler using the appropriate bolts, ensuring to tighten them to the specified torque.
Install the vacuum pump assembly
Install the rear cover plate of cylinder head
Install the EGR cooler component, and tighten the bolts to the specified torque
To properly install the EGR water inlet rubber pipe, first, connect it to the water outlet union pipe of the cylinder head Next, attach the water outlet rubber pipe to the large-circulation water pipe Ensure that the rubber pipe is neither twisted nor deformed before tightening the clamp securely.
The EGR mixing tube should be inserted into the air inlet union pipe with the inclined cut facing outward One end of the EGR air outlet pipe connects to the EGR cooler, while the other end is secured to the air inlet union pipe by passing through the mixing tube It is essential to remember to install the gaskets correctly, ensuring that the bulge of each EGR gasket faces the flange surface during installation.
To install the EGR bypass control valve, attach it along with the bracket to the rear lifting lug Connect the valve to the vacuum pump and EGR cooler using two vacuum rubber pipes, securing them with bolts and clamps.
Installation of accessories
Install fan support assembly and fan pulley
Install air conditioning compressor bracket and air conditioning compressor
Install the steering pump assembly
Install generator bracket and generator
Install PFM sensor and sensor base
To install the automatic tensioning wheel, first place the poly V-belt onto each belt wheel Use a square wrench to turn the automatic tension wheel to the left, allowing for the proper installation of the poly V-belt Once the belt is securely in place, loosen the tensioning wheel wrench Finally, rotate the crankshaft pulley more than two turns to ensure that the poly V-belt is correctly seated in each belt wheel groove.
Before installing the idler assembly, it is essential to apply an appropriate amount of thread-locking glue to the front end of the bolt Additionally, ensure that the bolts used for the smooth wheel in the idler assembly are left-handed bolts.
Install the blast pump, and the sealing ring of blast pump shall not be damaged
Installation, use, and maintenance of electronic-control high-pressure common-rail system
high-pressure common-rail system
The electronic control system comprises key components: sensors, the ECU control unit, actuators, and harnesses Each part plays a vital role, as illustrated in the accompanying figure Actuators include essential elements like fuel injectors and high-pressure oil pumps, while sensors encompass various types such as crankshaft and camshaft position sensors, water temperature sensors, air inlet temperature pressure sensors, PFM air-mass flow meters, accelerator pedals, and rail pressure sensors.
Schematic diagram of electronic control system
The China VI D20 series diesel engine features a BOSCH electronic-control high-pressure common-rail fuel injection system, which requires high-quality and clean diesel due to the precise manufacturing of its high-pressure oil pump and fuel injector It is essential to use diesel from reputable gas stations and ensure effective filtration; otherwise, Yunnei will not be liable for any damage to the electronic control system.
The main control functions of electronic control system are as follows:
The electronic control system directly manages the engine's startup process During ignition, the oil quantity control module regulates the oil supply, ensuring the engine starts smoothly and operates without producing black smoke.
The driver does not need to step on the accelerator for starting
The driver's intentions are communicated to the control unit via the electronic throttle opening, which adjusts the control output torque to manage the vehicle's acceleration This acceleration control encompasses several aspects, including limiting acceleration smoking, enhancing the driver's experience during sudden acceleration and deceleration, maintaining the maximum stable speed of an empty vehicle, and reducing torque when the engine cooling water temperature is excessively high.
Idle speed control allows the ECU to automatically regulate the engine's idle speed based on factors such as temperature, battery voltage, and air conditioning demands This closed-loop control system ensures the engine maintains a predetermined idle speed, adjusting accordingly; for instance, a lower cooling water temperature results in a higher idle speed, and activating the air conditioner while idling causes the engine speed to increase.
The preheating control module in the electronic control system enhances the intake air temperature during cold starts, facilitating a quicker engine start This module regulates the heating throughout the cold start process to minimize the risk of engine stalling When activated, the preheating indicator light on the instrument panel illuminates, alerting the driver to the module's operation.
Under the normal operation of engine, the exhaust brake module provides certain reaction force to reduce the running speed of vehicle
To activate the exhaust brake, the driver should use the exhaust brake request switch or the foot exhaust brake switch located on the instrument panel The electronic control system will manage the exhaust brake valve based on the driver's input and the engine's operating conditions When the exhaust brake is engaged, the engine will cease fuel supply.
To stop the exhaust brake, the driver should turn off the exhaust brake request switch or release the foot exhaust brake switch The ECU will then assess the control signal to decide whether to resume the oil supply.
The electronic control system in modern vehicles replaces the traditional mechanical engine control with an electronic accelerator pedal This system relays the driver's throttle input to the Engine Control Unit (ECU) via a control harness The ECU then calculates the appropriate fuel quantity based on the throttle position and engine speed, allowing the driver to effectively manage both engine speed and vehicle velocity.
7 Limp home and fail safe control strategy
When the electronic control system or harness experiences a serious failure, the ECU control unit activates fail-safe mode to ensure driving safety and protect the engine from potential damage This mode restricts the vehicle's maximum power, torque, and speed It is crucial for the driver to promptly take the vehicle to the nearest maintenance station for repairs.
When serious faults occur in the output signal of the electronic accelerator pedal or its harness, the ECU control unit activates limp home mode In this mode, the electronic accelerator pedal signal is substituted with a default fault value set in the ECU, rendering the accelerator pedal inoperative Consequently, the engine power is reduced, and a constant set speed is maintained for continued operation Drivers are advised to promptly take the vehicle to the nearest maintenance station for repairs.
In case of serious faults affecting safety, ECU will force shutdown
When the engine cooling water and fuel temperatures exceed safe limits, the ECU activates thermal protection mode to prevent engine damage This results in reduced maximum power, torque, and speed, allowing the vehicle to operate but with limited acceleration Once temperatures normalize, the engine resumes normal function Frequent occurrences of this issue necessitate prompt visits to a maintenance station for repairs.
9 Deceleration oil cut-off control
When the engine operates at high speeds and the accelerator pedal is abruptly released, the vehicle enters deceleration oil cut-off control mode if certain conditions are met In this mode, the ECU halts fuel injection, allowing the vehicle to coast due to inertia or while descending a slope.
As the engine speed decreases, the ECU will reactivate oil supply once it reaches a predetermined threshold, ensuring the engine continues to operate smoothly This deceleration oil cut-off strategy not only minimizes fuel consumption but also enhances emission control by stabilizing combustion Furthermore, it contributes to improved engine braking performance.
When the air conditioning request switch on the instrument panel is activated, the ECU detects the signal and regulates the engine to ensure it operates normally.
Installation and adjustment of engine assembly
Install the engine assembly in the reverse order of removal
After installing and securing the engine assembly, it is crucial to use soft water when filling the radiator Using hard water can lead to significant scaling, blockages in the water passages, and a diminished cooling effect.
To maintain optimal engine performance, unscrew the oil filler cap and fill the engine with CJ-4 or higher diesel engine oil until the oil level is between the two grooves on the oil scale.
Connect the fuel pipeline, and remove the air as follows:
Ensure the connecting pipeline is secure and free from air leaks Next, loosen the bolts on the diesel filter and use a hand oil pump to discharge the oil before tightening the bolts again.
After confirming that the connection of engine is secure, start the engine, and check for and eliminate the oil leakage, water leakage and air leakage.