All about Camshaft

Introduction

Camshaft, as the name suggests is the combination of the word ‘Cam’ and the word ‘Shaft’, is the part of the engine.

The shaft is nothing but a rotating mechanical component that is in circular cross-section and is used to transmit the power from the machine producing the power to the other machine that uses that power.

The word Cam is defined as a motion, rotational or sliding motion against a piece of machinery in order to convert rotational motion into linear motion.

Talking about automobiles, the camshafts are employed in all the automobiles and thus converts the rotational motion into linear motion.

The camshaft takes up the rotational motion indirectly from the pistons inside the cylinders after the combustion process and then rotates against mechanical component named cams that in turn slides up and down motion that controls the movement of the cars breathing system ie Valve Mechanisms.

The transmission ration of the crankshaft to the camshaft is about 2:1 which means for every 1 complete crankshaft rotation the camshaft rotates half.

The Camshafts on any automobile works very precisely and responsible for both the input of the fuel as well as the output of the fuel. The camshaft consists of a number of radial cams each displaces the valves. The camshaft is driven by the crankshaft through a belt mechanism. There is a separate camshaft for each row of cylinders.

Components

The main parts of a Camshaft are:-

We shall discuss each one the above in a brief,

Main Journals

The constant rotation of camshaft is responsible for the proper functioning, so main journals help the camshaft to be in the position as it spins in the engine bay.

Lobes

Lobes are nothing but a small mechanical component attached to the shaft eccentrically with the big end attached to the shaft side and the small end slides against the valves. These lobes follow Simple Harmonic Motion.

Ends

There are 2 ends. one end also is known to be the drive end has a geared pulley that is connected to the camshaft that actually drives the camshaft and the other end is connected to the distributor of the ignition system that is fine-tuned with the engine.

Bearings

Bearings are just added parts in addition to the main journals that allow the camshafts to spin seamlessly.

Camshaft Actuator

The camshaft actuator mounts to one of the ends of the camshaft that is responsible for either increase or decreases the speed of the valves for optimized performance and best fuel economy, electronically controlled by Engine Control Unit.

Materials for Camshaft Production??

Camshafts are usually made from metal and are usually solid, although hollow camshafts are sometimes also used. The materials used for a camshaft are usually either:

Cast iron: Commonly used in for high volume production, chilled iron camshafts have a good wear resistance since the chilling process hardens them.

Other elements are also added to the iron before casting to make the material more suitable for the application.

Billet steel: When a high-quality camshaft or low-volume production is required, engine builders and camshaft manufacturers’ steel billet is the priority.

Although this is a much more time-consuming process and is generally more expensive than any other method.

Why it is suggested to replace the whole cam kit??

The camshaft kit is a comprehensive set of components that are recommended to be changed when performing the repair.

The individual components of the valve opening system along with the control of Unit Injector System (UIS) consists of

These components work perfectly together and synchronously only if all parts that are worn are replaced correctly, and properly installed and when using the appropriate type of engine oil.

Creating such optimal working conditions will also greatly increase the life of the entire cam system.

Originally published at https://www.carengineered.com on July 8, 2020.