1.1.1STRUCTURE & FUNCTION SHOP MANUAL MT40B - 06.99 Chapter 1 Engine Main Index Chapter 1.1 Structure Function ..............................................................3 Chapter 12 Testing & Adjusting..............................................................33 Chapter 1.3 Disassembly & Assembly...................................................57 Chapter 1.5 Trouble shooting..................................................................163
1.1.3STRUCTURE & FUNCTION SHOP MANUAL MT40B - 06.99 Engine 1.1 Structure & Function Index Cylinder block ........................................................................................4 Cylinder liner 4 Pistons ....................................................................................................6 Piston rings ..............7 Connecting rods ....................................................................................8 Gear drive ..................................................................................................................................12 Belt drive ..............13 Oil pump .............14 Oil cleaner ..............15 Oil cooler CoolantThermostatChargeCoolingTurboLubrication...................................................................................................................................16oilways.........16filter...17system....................................20Circulation..................................................................................................................................21aircooler........................................................................................................................21andthermostathousing...........................................................................................22pump.............................................................................................................................23 Scania Digital Engine Control system (DEC2) ................................24 General .......24 Basic features ...........24 DiagnosticsImportantEngineEmissions..................................................................................................................................24protection.......................................................................................................................24information:.......24............25Faultfinding25 Control unit ..........................................................................................26 LED functions during normal operation .........................................27 CONTROL STATUS ....................................................................................................................27 SHUTDOWN ..............................................................................................................................27 STARTING .................................................................................................................................27 RUNNING ....27 TORQUE LIMIT..........................................................................................................................27 BOOST POWER+POWER-LIMIT............................................................................................................................27....................................................................................................................................27....27 Sensors ................................................................................................28 Note! ...........28 Engine speed.............................................................................................................................28 Charge air temperature ...............................................................................................................28 Charge air pressure ....................................................................................................................28 Coolant temperature ...................................................................................................................28 Oil pressure ............28 Junction box ..............................................................................................................................28 Sensor location ...................................................................................29 Electronically controlled actuator ...30 Control rack sensor ........30 Fuel shut-off valve.....................................................................................................................31 Throttle position sensor ..............................................................................................................31
1.Cylinder liner block head gasket
3.Cylinder
Cylinder block
4.Shim
SHOP MANUAL MT40B - 06.99 STRUCTURE & FUNCTION1.1.4
The cylinder block is a one-piece casting with 8 cylinders arranged in two rows at 90° to each other in a Vee configuration. There is a separate cylinder head for each cylinder. A steel gasket seals between cylinder block and cylinder head. Seals are bonded in place at the oil and coolant passages.
The cylinder liners are of “wet” type, i.e. they are surrounded by coolant. At the top of the cylinder liners is a loose scraper ring which removes residual carbon from the edge of the piston crown and reduces the risk of cylinder liner wear.
2.Cylinder
The cylinder liners and scraper rings are replaceable. To ensure a good seal, the edge of the cylinder liner stands 0.3 mm proud of the surface of the cylinder block. As a result, the cylinder head gasket is pressed against the cylinder head. The cylinder liner is adjusted to the correct height by means of a shim.
Cylinder liner
1.1.5STRUCTURE & FUNCTION SHOP MANUAL MT40B - 06.99
3.Seal for 4.Overflowoilhole
The V configuration of the cylinders means that the main bearings are also exposed to lateral stress. For this reason, the main bearing caps are attached with both vertical and horizontal bolts.
part of the cylinder liner is to some extent movable to allow for thermal expansion. Three sealing rings, 1 - 3, seal the lower part of the liner at different levels. An overflow hole which discharges in the side of the cylinder block is provided between the two bottom rings. Leakage in any of the sealing rings will result in oil or coolant coming out of the overflow hole.
1.Seal for coolant
The inside of the cylinder liner is machined by what is known as plateau honing. This type of machining leaves a fine pattern of grooves which ensure that the oil needed for lubrication between piston rings and liner remains on the wall of the liner. The design of the pattern is of major importance for ensuring low oil consumption in the Theengine.lower
2.Seal for coolant
SHOP MANUAL MT40B - 06.99 STRUCTURE & FUNCTION1.1.6
Fordissipation.thepiston
to resist the high pressure and high temperature prevailing in the combustion chamber, the material is thicker at the piston crown and piston ring grooves than in the remainder of the piston.
Pistons
The pistons are made of high-strength aluminium alloy characterized by low weight and good thermal
the greatest stress is on the upper piston ring groove, and also to reduce wear, a reinforcement of cast iron is incorporated in the piston.
The design of the piston and piston rings is important for the engine’s reliability and lubrication as well as for oil and fuel
combustion chamber in the piston crown has a protuberance in the centre. The design of this protuberance ensures that the fuel injected at the end of the compression stroke is quickly mixed with the air in the combustion chamber.
Sincewall.
1.1.7STRUCTURE & FUNCTION SHOP MANUAL MT40B - 06.99
Piston rings
For the piston to travel freely, a gap is required between the piston and cylinder liner.
The piston therefore has two compression rings which seal this gap and conduct the heat from the piston.
The upper of these rings is exposed to higher pressure than the intermediate ring and is therefore wedge-shaped, a “keystone” ring, which increases the force pressing it against the cylinder
The bottom piston ring, the oil scraper ring, prevents oil from the crankcase from finding its way up to the combustion Inchamber.theoilscraper
ring is a coil spring which presses it against the cylinder wall.
Theconsumption.bowl-shaped
SHOP MANUAL MT40B - 06.99 STRUCTURE & FUNCTION1.1.8
The connecting rod and big-end cap consist of a single casting which is split during the machining operation.
The upper part of the connecting rod is wedge shaped. This allows a larger journal surface on the underside of the gudgeon pin where load is greatest during combustion.
To prevent the big-end cap from being displaced in relation to the connecting rod, the contact surfaces are provided with grooves and guide pins. The surfaces are machined together to ensure a precise and accurate fit. The parts are also marked so that they can always be fitted in the same position.
Connecting rods
The connecting rod and big-end cap are split obliquely, partly so that the con rod bolts will not be subjected to excessive loads and partly to enable the piston and con rod to be withdrawn through the cylinder.
Each compression stroke ”brakes” the crankshaft and each combustion stroke attempts to increase the speed of rotation of the Thecrankshaft.pistonsand
connecting rods change their direction of travel twice during each rotation of the crankshaft. This exposes the crankshaft to numerous power pulses during each revolution.
The material is of major importance for the useful life of the crankshaft. Its design and surface treatment also help to extend its life - for instance, the surface quality of the shaft journals is an important factor in providing protection against fatigue
Thefailure.bearing
The bearing shells of the main and big-end bearings consist of three layers. An outer layer or backing of steel, an interlayer of lead-bronze and nearest the crankshaft an overlay consisting of a mixture of lead and indium or lead, tin and copper. The innermost layer is usually worn away during the course of engine utilization.
surfaces on the crankshaft are hardened to a depth which allows them to be ground several times.
1.1.9STRUCTURE & FUNCTION SHOP MANUAL MT40B - 06.99
Only the bearing surfaces are hardened as it is important to retain the toughness of the material in other parts.
Crankshaft
Thrust washers are used for endways location of the crankshaft at the rear main bearing. These thrust washers are available in different thicknesses so that the crankshaft can be adjusted to the correct clearance. The thrust washers have the same types of layer as the big-end bearing shells.
There is a heavy oil between the housing and ring which damps the relative movement between the two. The oscillation at the front of the crankshaft is damped by the ring striving to rotate with even speed.
Torsional oscillation is characterised as follows: The flywheel (at the “rear of the crankshaft) rotates with even speed throughout the revolution. When compared with the flywheel, the front end of the crankshaft will increase and decrease speed of rotation several times during each revolution.
SHOP MANUAL MT40B - 06.99 STRUCTURE & FUNCTION1.1.10
This oscillation may give rise to noise from the timing gears and increases the risk of crankshaft breakage. To reduce the oscillation a crankshaft damper is attached to the front end of the crankshaft.
Crankshaft damper
A ring of steel is incorporated in the circular and completely enclosed housing of the crankshaft damper. The housing is bolted onto the crankshaft.
The power impulses from the connecting rods give rise to torsional oscillation in the crankshaft. These oscillations are severest at a certain rpm which varies with the design of the engine, how it is loaded, etc.
The pushrods are inside the valve tappets and transmit, via the rocker arms, the movement from the camshaft lobe to the valves.
The camshaft is located high up and driven by the timing gears. It rotates at half the speed of the crankshaft. The camshaft cams (lobes), two for each cylinder, actuate the valve tappets.
The valve seat ring can be replaced.
The valves seal against valve seat rings which are pressed into the cylinder head.
Valve mechanism
The valve mechanism actuates the valves, causing them to open and close at the right times.
1.1.11STRUCTURE & FUNCTION SHOP MANUAL MT40B - 06.99
At one end of the rocker arm is an adjusting screw so that the correct clearance can be set to ensure that the valve will close properly during combustion.
Transmission
To facilitate correct assembly of the timing gears, the gears are marked on a tooth or in a tooth space.
By means of an intermediate gear, the gear on the crankshaft drives the camshaft and oil pump. The camshaft gear in its turn drives the gears for the injection pump, coolant pump and fan.
1.Crankshaft 2.Intermediategeargear3.Camshaftgear4.Gearforcoolantpump 5.Gear for fan drive 6.Gear for injection pump 9.Gear for oil pump
SHOP MANUAL MT40B - 06.99 STRUCTURE & FUNCTION1.1.12
Important components such as the injection pump and valve mechanism require precise control and are therefore driven by gears.
Gear drive
B.AirA.AlternatorcompressorC.ACcompressor
In the large gears is a retaining ring for damping oscillation, which also reduces the noise level.
Belt drive
1.1.13STRUCTURE & FUNCTION SHOP MANUAL MT40B - 06.99
It is two belt drives, one for the alternator/air compressor and one for the AC compressor.
The oil pump is of gear type driven by the engine timing gears. Incorporated in the oil pump is an oil pressure valve which prevents the pressure from becoming too high.
SHOP MANUAL MT40B - 06.99 STRUCTURE & FUNCTION1.1.14
Lubrication system
The lubricating oil is sucked from the sump through a strainer in the oil pump.
Oil pressure must be sufficiently high for the required quantity of oil for lubrication and cooling to reach each lubrication point. Too high oil pressure could cause excessive stress to components in the lubrication system.
When the oil is cold the pressure is more likely to be high and for this reason an oil pressure valve is integrated into the oil pump. If the pressure is too high the oil pressure valve will allow oil to escape (and run back to the sump), so that the pressure never rises high enough to cause any damage.
Oil pump
The oil containing particles of dirt is forced up into the oil cleaner’s centrifuge.
The oil is caused to rotate in the cyclone where particles of dirt and some of the oil are separated from clean oil through centrifugal force. The clean oil is subsequently distributed to all the various lubrication points.
1.1.15STRUCTURE & FUNCTION SHOP MANUAL MT40B - 06.99
The lubricating oil continues to the oil cleaner, which consists of two parts: cyclone cleaner and centrifugal cleaner.
Oil cleaner
The centrifugal cleaner’s rotor is caused to spin by the force of the oil which squirts out through two nozzles at the bottom of the Particlesrotor. of dirt are forced against the wall of the rotor by centrifugal force where they become attached as a deposit.
The rotor must be dismantled and cleaned at definite intervals.
oil to the rocker arms is lead through an oil way in one of the camshaft pivot pins. These oilways are opened once for each revolution of the camshaft and provide the correct quantity of oil to the rocker arms.
The oil passes from the oil cleaner to the oil cooler. All the oil goes through the oil cooler, which is cooled by coolant from the cooling system.
Oil cooler
The big-end bearings receive oil through oilways in the Lubricationcrankshaft.
SHOP MANUAL MT40B - 06.99 STRUCTURE & FUNCTION1.1.16
Lubrication oilways
Oilways in the cylinder block carry oil to the camshaft bearings and crankshaft main bearings.
Thank you very much for your reading. Please Click Here. Then Get COMPLETE IfNOTE:MANUAL.NOWAITINGthereisnoresponse to click on the link above, please download the PDF document first and then clickonit.
Turbo filter
1.1.17STRUCTURE & FUNCTION SHOP MANUAL MT40B - 06.99
The pistons are cooled by engine oil which is sprayed into an oilway in the piston by piston cooling nozzles, one for each cylinder,
The filter cartridge also has a valve which can release oil to the turbocharger if the filter becomes blocked. The filter should be changed at the intervals given in the Scania inspection programme.
The oil to the engine’s turbocharger must be especially clean. It therefore goes through a further purifying stage, a filter cartridge with a paper filter.
High-output engines for pleasure boats (750 hp) have two water-cooled turbochargers.
is driven by the engine’s exhaust gases and consists of a turbine part and a compressor part. The compressor part compresses the engine’s intake air. The turbocharger’s shaft runs in a bearing housing between the turbine wheel and compressor wheel.
The purpose of the turbocharger is to increase the volume of air entering the engine’s cylinders. With more air the engine can burn more fuel and so develop more power and achieve cleaner combustion than a corresponding engine without Thesupercharging.turbocharger
The turbocharger wheel rotates extremely fast. At full power, speed is about 100,000 rpm. At the same time, the temperature on the exhaust side of the turbine wheel is above 600 °C. This makes big demands on the rotating parts in regard to balance, cooling and lubrication.
Higher power output from the engine gives more exhaust fumes and the increased exhaust means that the turbine wheel and therefore the compressor wheel rotate faster. In this way, the quantity of air is adapted to engine requirements without any special control devices.
The shaft is mounted in two bushings which rotate freely in the bearing housing. The bearing housing seals for the turbine and compressor consist of seals which are similar to piston rings.
SHOP MANUAL MT40B - 06.99 STRUCTURE & FUNCTION1.1.18
Turbocharger
1.1.19STRUCTURE & FUNCTION SHOP MANUAL MT40B - 06.99
3.Intake piping for air
1.Charge air cooler
Charge air cooling
2.Coolant radiator
By cooling the air after the turbocharger, more air can be pressed into the cylinders, more fuel can be burnt and more power can be developed by the engine. Some engines therefore have a charge air cooler (“intercooler”).
Liquid-cooled, DSI, with the charge air coolers mounted in the intake manifolds.
• External heat sources (e.g. cab heater) connected to the cooling system.
SHOP MANUAL MT40B - 06.99 STRUCTURE & FUNCTION
A complete cooling system for DSI14 engine consists of:
system keeps the engine’s operating temperature at a suitable level when the engine is in use. This is of major importance for the engine’s operating economy and service life.
- The engine’s internal cooling system:
• Coolant pump.
• Cooling fan
• Oil cooler for engine oil.
6.Thermostat housing
7.Cooling fan
8.Fan 9.Ventingringlines10.Levelindicator
The1.1.20cooling
Cooling system
• Thermostat housing with thermostat and bypass duct.
Complete cooling systems for Scania engines have a sufficiently high capacity for working at atmospheric pressure, which ensures a more reliable system.
• Coolant passages in cylinder block and cylinder head.
• Radiators and expansion tank.
- External cooling system:
Scania cooling systems are therefore supplied as standard without a pressure cap.
• Temperature gauge and level indicator.
• Lines (pipes and hoses).
• Engine heater.
1.Expansion tank 5.Coolant4.Drain3.Static2.Radiatorlinetappump
