Camshaft vs Crankshaft – Basic Difference

Difference Between Crankshaft and Camshaft Used For Automobile

In Automobile Engines Crankshafts and camshafts used to running the mechanism of power Generation, These both shafts have different applications, construction, and location. Many students get confused in between these two shafts. So today we will discuss about Camshafts and Crankshafts in details.

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Difference Between Crankshaft and Camshaft Used For Automobile 
Difference Between Crankshaft and Camshaft Used For Automobile

Crankshafts:

The crankshaft of an engine is a shaft as the name suggests on which all the units of an engine are mounted. When the piston move or reciprocate up and down this movement is transferred down to the crankshaft by the piston rod and crank to the crankshaft.
The crankshaft is what coverts the reciprocating motion of the piston to rotational motion useful for propulsion.

Construction Of Crankshaft:

A crankshaft is simply the same as an eccentric, except the eccentric is a much smaller diameter than the shaft itself Crankshaft length mainly depends on the number of cylinders are present in the engine .Firing orders also considered while designing the Crankshaft.

Location of Crankshaft :

The crankshaft is located in a crankcase . On Crankshaft, Connecting rods and pistons are mounted. The crankshaft rides on bearings which can wear down over time. The bearings support the crankshaft and also the rods which connect the pistons to the crankshaft.

Applications of Crankshaft :

Its actually part of an engine where the power is available, and this power is transferred in the form of torque to clutch and thereby gearbox and wheels.

Camshafts:

As the engines work they need to breathe out exhaust gases and take in fresh air ( charge) for the next cycle to take place. All these processes need to take place at a designated time with respect to each other. These processes are timed through the opening and closing of valves and actuation of fuel pumps through an actuating mechanism that is triggered by the movement of the crankshaft. The camshaft comes into the picture here. The Crankshaft drives through a belt or chain drive the camshaft on which the inlet, exhaust, fuel pump cams are fitted for each unit when the crankshaft rotates it, in turn, rotates the camshaft which precisely actuates the valve and fuel pumps.

Construction Of Camshafts:

A camshaft is a long bar with egg-shaped eccentric lobes, one lobe for each valve, and a fuel injector.
The relationship between the rotation of the camshaft and the rotation of the crankshaft is of critical importance. Since the valves control the flow of the air/fuel mixture intake and exhaust gases, they must be opened and closed at the appropriate time during the stroke of the piston. For this reason, the camshaft is connected to the crankshaft either directly, via a gear mechanism, or indirectly via a belt or chain called a timing belt or timing chain.

Location of Camshaft :

Depending on the location of the camshaft, the cam operates the valves either directly or through a linkage of pushrods and rockers. The direct operation involves a simpler mechanism and leads to fewer failures, but requires the camshaft to be positioned at the top of the cylinders.

Applications of Camshaft :

this shaft receives the power from crankshaft  (1:2) and operates the engine valves through the cam and follower mechanism(generally mushroom-headed follower is used to reducing friction b/w cam and follower).

Camshaft Vs Crankshaft :

Difference / Comparison between Camshaft and Crankshaft are as follows, 
Sr no. Crank ShaftCam Shaft
1.It is the part of an engine where the brake power is available.This shaft used to operate inlet and outlet valves.
2.Two revolutions per power stroke in the Four-stroke engine.One revolution per power stroke in Four-stroke engine.
3.Available in both two-stroke as well as in four-stroke engine.Available only in a four-stroke engine.
4.More weight.Less weight
5.The crankshaft is located in the crankcase.The camshaft is located either in the crankcase or on the cylinder head
6.It consists of crankpin, main journal bearing,
crank web, oil hole
It consists of integrated cams and gear.

The relation between camshaft speed and crankshaft speed:

The camshaft is driven by the crankshaft either by a pair of meshing gears (timing gears) or by means of a pair of timing sprockets connected by a chain. The camshaft gear or sprocket has twice as many teeth as the gear or the sprocket on the crankshaft. This gives a 1:2 gear ratio, the camshaft turns at half the speed of the crankshaft. Thus every two revolutions of the camshaft produce one revolution of the camshaft and one opening and closing of each valve in the four-cylinder engine. The gear and sprocket maintain a definite time relationship between the camshaft and crankshaft to ensure opening the valves exactly at the correct time in relation to piston position

Sachin Thorat

Sachin is a B-TECH graduate in Mechanical Engineering from a reputed Engineering college. Currently, he is working in the sheet metal industry as a designer. Additionally, he has interested in Product Design, Animation, and Project design. He also likes to write articles related to the mechanical engineering field and tries to motivate other mechanical engineering students by his innovative project ideas, design, models and videos.

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