Crankshaft, Bearings and Related Component Fundamentals pg 248 Flashcards
List 2 functions of the crankshaft.
A. Converts the reciprocating motion of the piston and connecting rods to rotary motion.
B. Drives the camshaft and engine accessories.
Identify the parts of the crankshaft in figure 45.
A. Nose B. Web. C. Fillet radius. D. Counterweights. E. Flange.
What is the purpose of the internal drilling of the crankshaft?
The internal drillings provide a path for oil to travel from the main bearing journals to the connecting rod journals.
Crankshafts used in medium and high speed diesel engines are usually:
B. One piece forged alloy steel.
The crankshafts used in diesel engines are usually hardened to improve the wear characteristics of the: A. Nose B. Journals C. Webs. D. Counterweights
B. Journals
List four factors that determine the arrangement of the throws on a crankshaft.
A. Number and arrangement of the cylinders.
B. Firing Order
C. Engine Balance
D. Main Bearing Loads
Determine the number of degrees between firing impulses on a two stroke cycle engine with sixteen cylinders.
22.5 Degrees
Determine the mating cylinders for a four stroke cycle, eight cylinder engine with a firing order of 1-5-4-8-6-3-7-2.
1/6, 5/3, 4/7, 8/2
An unbalance engine would have reduced:
C. Mechanical efficiency.
List the 3 basic functions of the flywheel.
A. Smoothes out engine operation by storing and releasing energy.
B. Carries the ring gear.
C. Provides a mounting and friction surface surface for the clutch assembly.
The balance weights used in some four stroke cycle diesel engines:
A. Absorb and release energy to smooth engine operation.
B. Counterbalance inertia forces generated by the piston and rod assemblies.
C. Counterbalance torsional forces generated by the piston and rod assemblies.
D. Counteract inertia forces.
B. Counterbalance inertia forces generated by by the piston and rod assemblies.
List 2 types of vibration dampners used on diesel engines.:
A. Rubber element.
B. Viscous
Briefly explain the purpose of a vibration dampner.
The vibration dampner counteracts or opposes the twisting forces acting on the crankshaft, reducing torsional vibration.
The front and rear crankshaft seals:
A. Prevent pressurized oil from entering the crankcase.
B. Maintain crankcase pressure.
C. Control lubrication of the front and rear main bushings.
D. Prevent splash oil from leaking out around the rotating crankshaft.
D. Prevent splash oil from leaking out around the rotating crankshaft.
List two functions of the crankshaft gear.
A. Transfers power to drive engine components and accessories.
B. Time the crankshaft to the camshaft using marks on the gears.
List the two types of friction bearings used in diesel engines.
A. bushing
B. shell
What bearing term is represented by dimesion A in figure 46?
Spread
Locating lugs and dowels are used to:
A. Stop bearing shells from rotating during engine operation.
B. Index the main caps to the cylinder block.
C. Position the bearing shells in the main bearing bore.
D. Ensure the initial seating of the bearing during assembly.
C. Position the bearing shells in the main bearing bore.
List four basic properties that friction type bearing materials must posses.
A. Embeddability
B. Conformabillity
C. Fatigue resistance.
D. Corrosion resistance.
Briefly explain the purpose of bearing crush.
The press fit that seats the bearing halves to provide good heat transfer and keep them from rotating in the bore.
What is the purpose of an oil spreader groove?
An oil spreader groove aids in oil distribution across the bearing face.
What is the purpose of bearing clearance?
Bearing clearance allows oil to flow between the bearing surface and the shaft.
List two purposes of the oil film between the bearing and the crankshaft journal.
A. reduces friction
B. Carries heat away from the bearing and journal.
Maintaining the film of oil between the bearing and the crankshaft journal is dependent on engine oil pressure and the principle of
hydrodynamic lubrication.
