4D95 Diesel Used Engine Blocks For Excavator PC130 - 7 6205 - 21 - 1513
|Car name: Engine cylinder block|
|Model Number: 4D95|
|Work form: Turbo|
|Number of Cylinder: 4|
|valve: 8 valve|
|Cooling: Water cooling|
With respect to the engine block, it is essential to adapt its design, the applied casting process, the selected alloy composition and heat treatment as well as the method used to ensure an appropriate cylinder bore surface quality.
Requirements for aluminium engine blocks
The application of aluminium for engine blocks poses a certain challenge, in particular with respect to diesel engines. The required rigidity and strength, the realisation of a reliable bolting concept for the cylinder head and the main bearings as well as the resulting increase of the crankshaft clearances and the inferior acoustics require specific solutions. On the other hand, an aluminium engine block benefits not only from the lower density compared to grey cast iron, but also from the high specific modulus of elasticity and the very good heat conductivity.
1. Thermal conductivity
Modern aluminium engine blocks "see" temperatures of 150°C in crank-shaft bearings and up to 200°C in the inter-bore regions. The high thermal conductivity of cast aluminium alloys ensures efficient heat dissipation into the coolant.
2. Strength at elevated temperatures
An adequate static strength level up to temperatures of 150°C (oil temperature) is required mainly in the joint face with the cylinder head due to the load of the head bolts and in the bearing saddles to withstand the forces coming from the crankshaft rotation and the thermal expansion of the engine block.
3. Strength / hardness at room temperature
A minimum room temperature strength / hardness of the aluminium alloy is necessary to ensure good machinability (depending on the machining parameters) and for assembly.
4. Fatigue strength
During operation of the engine, the engine block is subjected to cyclic tensile stress in a wide temperature region ranging from sub zero temperatures (when the engine is started in the winter) to elevated temperatures corresponding to the oil temperature of about 150°C. A most important material characteristic for engine block design is therefore the fatigue strength.
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