GENERAL INFORMATION MX-13 ENGINE
The MX-13 engine is compliant with Euro 6 emission regulations. The MX-13 engine has the following technical layout:
- 6-cylinder in line
- 4 valves per cylinder
- Common Rail Diesel Direct Injection
- Exhaust Gas Recirculation (EGR)
- PCI engine control system (PACCAR Common Rail Injection)
- EAS-3 (Emission Aftertreatment System)
- VTG (Variable Turbo Geometry) with intercooling
- Bore & stroke 130 x 162 mm
- Displacement 12.9 ltr.
- Compression ratio 17.7:1
- Weight approximately 1260 kg.
PACCAR Common rail Injection (PCI)
The main task of the PCI engine management system is to control the engine so it runs as smooth and efficient under all possible circumstances. An in-depth description of the functions and controls of the PCI is covered in a separate module. The heart of the PCI is the electronic control unit (ECU), a sophisticated computer which contains electronic power supplies, central processing units, memory, sensor input circuits, and output driver circuits. On some equipment the ECU may communicate with other electronic controls via the CAN network. The ECU functions as the electronic governor controlling the fuel system. The ECU receives input signals from the sensors and other systems like EAS (Emission Aftertreatment System). The ECU energises the solenoids from the injectors and common rail pump units to control timing and engine speed accurately.
The electronic control unit is mounted on the cylinder block with rubber insulating bushes (2). The electronic control unit has two 62-pin connectors and a 92-pin connector. Input signals from various sensors are continuously processed and compared with data stored in various maps (tables) in the electronic control unit. Actuators are energised on the basis of the signals received and the maps. The housing (1) of the electronic control unit is directly connected to the engine block. The electronic control unit incorporates an atmospheric pressure sensor and a temperature sensor. There is an air vent (3) for the atmospheric pressure sensor in the housing of the electronic control unit. An identification sticker (4) is attached to the electronic control unit.
CYLINDER HEAD AND VALVE COVER
The cylinder head is a one-piece cylinder head, made of compact graphite iron with integrated high pressure lines to feed the injectors. Four valves are used per cylinder, actuated from a camshaft that is positioned in the cylinder block. The inlet manifold is integrated in the cylinder head. The cylinder head is mounted to the cylinder block with a steel multi-layer gasket.
The valve cover covers the valves and is made of cast aluminium. The crankcase gases collect here and led through a labyrinth before being discharged to the crankcase ventilation module.
PISTONS AND LINERS
The one-piece pistons are made of steel with a closed gallery. The arrow on the piston must point towards the front of the engine. Oil jets cool the pistons by spraying a large amount of oil into the piston gallery in the piston head. The gallery is equipped with holes through which the oil is supplied and discharged back to the oil sump.
The cylinder liners (3) contain an anti-polishing ring (2). This ring has a slightly smaller inner diameter compared to the cylinder liner and prevents carbon build-up on the upper part of the piston (1). Any such deposits are harmful since they disturb the oil film on the cylinder liner, which again leads to liner polishing. The anti-polishing ring (APR) does not need to be specifically fixated, as it is kept perfectly and tightly in place by thermal expansion.
CRANKSHAFT AND BEARINGS
The engine has a crankshaft with seven bearings. The thrust bearing of the crankshaft is placed on the 7th main bearing. The crankshaft has no balance weights. For a correct balance the crankshaft journals have holes drilled in them. The vibration damper is attached to the attachment flange at the front of the crankshaft. The drive gear drives the camshaft and the air compressor via the idler gear. The crankshaft gear wheel drives the oil pump directly. The flywheel is fitted on the attachment flange, which is pressed on the crankshaft.
The connecting rods are split fractured to keep the machining of the bearings exact. This process also provides a much bigger mating surface between the parts (1). Care must be taken when handling the main bearing cap and the connecting rod and rod caps, to prevent damage to the mating surface. Each cap is marked with an identification that must be matched with its original position.
The bottom of the engine block has a sump reinforcement plate. This reinforcement plate stiffens the construction of the bottom of the engine block, so the engine produces less noise. The sump is made of special reinforced polymer material. The sump is bolted directly to the engine block flange with pre-mounted bolts with metal inserts (detail A). The gasket is pre-mounted in a groove (detail B). The sump is equipped with a bayonet drain plug (C) and an oil level sensor (D).
All engine combustion processes produce exhaust gases. A small portion leaks from the combustion chamber down into the crankcase where the exhaust gases mix with oil and turn into crankcase gases. These gases must be discharged constantly to prevent pressure building up inside the crankcase. The emission of oil (airborne and oil borne) coming out of the crankcase ventilation, is restricted to certain values (demands by several governmental rules). The crankcase ventilation module must be able to remove oil out of the crankcase gas stream to a certain amount. When the gases leave the module they flow back to the environment.
A crankcase ventilation module protects both engine and environment. The stringent Euro 6 emission limits prohibit that blow-by gases which are loaded with oil mist are discharged into the environment in an unclean form. The crankcase ventilation module performs these required cleaning functions and returns the separated engine oil to the oil sump. The cleaned gas is compliant with the emission regulations and can be transported to the environment.
The crankcase ventilation module is based on the centrifuge principle. Crankcase gas, that contains a certain amount of oil mist, enters the module at the lower connection (red arrow). An electrical driven, internal element with 98 circular discs rotates at 12.000 rpm, separates the heavier oil mist from the crankcase gas.
The separated oil is thrown outwards against the wall, drops down and is collected in the lower part of the housing. From there the oil drains back to the oil sump via the drain valve and the connection (yellow arrow). The connection is covered to prevent oil splashing from the sump into the connection.
The cleaned gas leaves the module at the top connection (blue arrow) and flows to the road draft tube. The crankcase ventilation module is maintenance-free. For diagnostic purposes the rotating element has a speed sensor (Hall-sensor) that reads the magnet of the motor to provide feedback on its operation to the PCI ECU.