An integral component of an internal combustion engine is the camshaft, which has been around since the dawn of the internal combustion engine. As far as the principle of operation of automobile engines is concerned, it has remained the same till this 21st century. It is important to understand the difference between camshafts and lobes of cams. The camshaft is the length of the rod or shaft that contains the cam lobes.
Camshaft is through the rotation of the shaft that the shape of the cam actuates a valve. During the compression and exhaust strokes, it presses against valves to open and close them in order to create compression and exhaust pressure. The speed at which the rotation is carried out determines the rate at which its actions are carried out.
What is Camshaft? Definition, Features & Purpose
What is Camshaft? Definition
Camshafts is basically a rod-type structure that allows rotary motion to be converted mechanically into reciprocating motion by mechanically turning them. Essentially, the camshaft is used to transmit the rotational motion of the camshaft to the filter or follower by converting it into a reciprocating motion. Fuel is sucked into the engine through this shaft and discharged from the engine through this shaft.
There are many types of camshafts, but the one most common is the camshaft that is attached to an engine, which is responsible for regulating the opening and closing of an internal combustion engines inlet and exhaust valves. It contains a lot of radial cams, each of which displaces an inlet valve or an outlet valve, and the camshaft is slid over these two mentioned valves. According to the design of the engine, the camshaft’s position varies depending on how it’s mounted.
- Crankshafts transfer motion to camshafts using gears, chains, or belts that are attached to the crankshaft. As a result, the valve timing is assured based on the piston’s movement in relation to the valve timing.
- In order for the camshaft to function correctly, both the valves and the cam have to be working correctly.
- A camshaft is installed on the inlet and outlet valves, which are located on the head of the cylinder.
- There is a blockage of the nozzle that is responsible for allowing fuel to be sucked or discharged and requires reciprocal movement in the cylinder head.
What are the Features of Camshaft?
Below mentioned a few brief features of Camshafts in your car:-
- In relation to the transmission of energy between a mechanical element and another, a camshaft is a mechanical component that has a curved shape.
- In a piston engine, the camshaft primarily serves the purpose of opening and closing the valves.
- Crankshafts are generally used for operating camshafts.
- Camshafts have a speed of about half as fast as crankshafts, and they can either exhibit rotary motion as well as oscillatory motion, in addition to reciprocating motion.
- As the name implies, camshaft mechanisms consist of three main components, namely the driver member referred to as the cam, the driven member referred to as the follower, and the supporting member, which in essence is a structure or frame constructed to hold them both in place.
- Among the advantages of camshafts is that they are capable of building torque in all ranges, regardless of whether they are configured for high or low torque.
- By using them, valve-actuating mechanisms can be made more dynamic by improving the dynamic characteristics of the mechanism.
Various Purposes of Camshafts in a car
Following are a few primary purposes of camshafts in a car:-
- Basically, a camshaft is a device that regulates the timing of the intake, exhaust, and other valves on a car, and it also controls the overlap between the intake and exhaust valves that occur at the top dead center of the exhaust stroke.
- In the engine of a car, each camshaft is constructed with several journals that use bearings to prevent the camshaft from detaching from the chain.
- Usually, these valves are operated by actuating the lifters and pushrods of the valve train, or by pushing directly on the stems of the valves in order to open the valves.
- Talking about the camshafts we should not forget about crankshafts, when the camshafts fail to drive, causing the valves to contact the piston crowns, extensive damage to the internal components of the engine can occur, as the valves are bound to the crankshafts by a rotating chain or trimming belt, and such failure may result in extensive internal damage to the engine.
- As an alternative to machining gears into the camshafts in older engines, there may also be gears machined into the shafts that operate the oil pumps and the distributors.
- A position sensor is typically mounted on the end of the camshaft on new engines, and it sends these measurements to the power train control module so that it can effectively time the injection pulses and ignition according to the engine’s needs.
- The valve train of a desmodromic engine is usually composed of at least two cams, one of which acts as a push-open cam and the other as a pull-close cam, rather than the traditional push-open cam with the valve springs pulled down so that the valve was shut as the cam rotated past the lobe and back to the base circle.
Parts of a camshaft
Below mentioned a few components that are used in a camshaft:-
Cams are devices that are designed to transfer the movements required to the followers through direct contact with the cam. There are multiple cams installed on each engine’s camshaft, each of which has its own motor, and in order to install the cam, the valves must be installed first.
It is important to note that the cam timing of internal combustion engines is very crucial to their performance. A cam is a piece of machinery that rotates and opens the exhaust valve and the suction valve on a cylinder. The timing is crucial to the proper injection of fuel at the right time as well as the appropriate expulsion of that fuel.
With its non-circular design and a single lobe, it has a non-circular profile. In order for the followers to move, the cam must turn in order to move the followers. Injectors and exhaust valves are controlled by this valve, which controls when they are opened and closed. A camshaft’s main function is to convert the rotary motion of the crankshaft into linear motion in the transmission of power.
A camshaft bearing can be considered one of the most important parts of a camshaft as they are responsible for holding the shafts in the correct position and are also responsible for reducing friction during camshaft operations. There is also an oil inlet on the camshaft which ensures that the oil in the camshaft is always changed in a continuous manner.
Bearing journals in the camshaft
There are two types of bearing journals, one that is present in close contact with the followers while the other is a part that rotates on the camshaft. It is a device that transforms the rotatory movements into linear movements by turning them into circular motions.
In general, the bearing journals are scaled with a bearing shell that sits on the top of the journal. Bearing shells serve the purpose of smoothing the rotation of a camshaft and protecting the engine against being damaged or shattered in case of an engine failure, by preventing wear and tear of the bearing shell during rotation.
Track Follower in a camshaft
As the name implies, a track follower is nothing more than a roller or a needle bearing that follows the cam love profile in order to operate, and it is also known as a cam follower. A cam follower can be configured in a number of different ways, but the most important feature is the way in which it is attached to the mating part, which is responsible for the rotation of the cam follower. A yoke cam follower features a hole in its center, whereas a stud cam follower uses a stud as its mounting point instead of a hole.
A follower bearing can also have a variety of designs, but in most cases, the outer ring is constructed with a very thick material. Despite the fact that the outer rings of the bearing are thick, this design promotes a large amount of radial load absorption by the follower. In order for a cam follower to translate its rotary motion into reciprocating motion, it has to be equipped with cam follower bearings in order to operate.
A camshaft is a significant part used to convert rotatory motion into reciprocating motion, but if there is no camshaft in place, there is no advantage to the cam since the cam takes support from the follower. Soft cores can withstand large amounts of load without causing component damage. According to the needs of the application, cam followers require balls or needles, as well as special materials such as stainless steel or chrome to be able to function properly.
Lobes of camshafts
In order to make the piston move with the camshaft, the lobes rotate with the camshaft. Essentially, the purpose of the lobes of a camshaft is to open and close the valve which allows air to enter and leave the engine. Depending on the speed of the car’s engine, the operation of the lobes directly depends on how fast the engine is going.
Sprockets of the chain
An engine’s timing belt is attached to a chain sprocket at the end of the camshaft for the purpose of retaining it. This sprocket is connected to a chain by means of a pawl. There is no need to touch these sprockets so that they will be able to turn at the same speed even if they are not in contact.
A belt is designed to be attached to the front end of the cam so that it can be connected to the crankshaft by the belt. In order to operate the engine, the rear end of the camshaft is connected to a special gear that turns the distributor. This part is in a position to match the ignition timing of the rest of the engine with the rest of the ignition system.
Woodruff key in camshaft
Among the most crucial components of a camshaft is the woodruff key, which is one of its most important parts. In addition to its other purposes, it also serves to ensure that the camshafts move at the desired timings, among its other functions.
Thrust Plate in camshaft
It is necessary to have a thrust plate for the rear cam to provide support, and it is mounted up the front cover of the engine and it attaches to the cam between the rear gear and the cam itself.
How Does a Camshaft in a Car Engine?
As a camshaft spins, the lobes, either on the intake or exhaust valves, open and close in time with the piston motion, indicating the direction in which the piston should be moving as the camshaft rotates. Apparently, there is a direct correlation between the shape of the cam lobes and the performance of an engine in various speed ranges depending on the shape of the cam lobes.
- An important aspect of the functioning of a camshaft is how a valve works, as well as the function of the cam itself.
- There are two basic components of a valve on a cylinder head, namely the stem and the head. Heads plug the nozzles that allow fuel to get into engines or exhaust gases to escape through them, and they must move linearly.
- This displacement is achieved by a cam on the camshaft making use of a radial pattern that is rotated by a follower which moves perpendicular to the rotational axis, thereby achieving the displacement.
- An engine camshaft has a non-circular cam pattern, which consists of a single lobe of a cam.
- During the rotation of the cam, the follower is matched to the displacement caused by the cam. It is then from this displacement that the lobes of the cam pass through the follower and the head rise as the lobes of the cam pass through the stem of the valve.
- As these cams are precisely positioned along the shaft, the timing of how the relative valves open and close can be precisely controlled by the precise position of the cams.
- In a car, the engine fires at thousands of rotations per second, so precision timing is crucial in order to achieve optimal performance.
- There are many ways to save money and energy on a car engine, and one of the simplest ways to do that is to ensure the timing is set properly.
Materials used in Camshaft Construction
In order to obtain rigidity, camshafts are made from metal. As cast iron offers such a strong, durable material, it is ideally suited for mass production because of its strength. As a result of the chilling process, turned iron camshafts are resistant to wear, due to the fact that they are hardened.
When low-volume production in high-quality and high-volume conditions is required by a manufacturer, billet steel is used. There are a few disadvantages, such as the fact that it is a time-consuming and expensive method.
Forging, casting, or machining methods are the methods used in its construction, and steel bars can also be used for its construction, or metal lathes or milling machines can also be employed to make the parts. In order to obtain more suitable properties for the specific application, certain additional elements are added to the iron before it is cast in order to improve its properties.
Camshafts come in a Variety of Types
Below mentioned a few varieties of Camshafts:-
Roller Camshaft type
In order to install the roller cams, there is an arrangement of wheels and axles. Wheels are attached to the body of the lifter by needle bearings, which are supported by the base of the lifter body. Roller camshafts have flat lobes which make them easy to operate. In order to prevent the roller camshafts from rotating or spinning, they are locked together in a way that prevents them from being rotated. It has been proven that roller cams have an advantage over conventional cams because they reduce friction and therefore increase power as a result.
Furthermore, such cams have a very low rate of wear and tear, which translates to a longer cam life. There are also some ways in which roller camshafts can be used in order to improve the efficiency of an engine. This is because they cause the valves to open faster and stay open for a longer period of time, allowing better intake of fuel and exhaust of exhaust gases.
Plate camshaft type
This type of cam is sometimes referred to as a disk cam, plate cam, or radial cam. A follower is a mechanism for transmitting motion from a driven member or a driven member to a follower that is made up of an irregular contour plate. Disk cams have an axis perpendicular to the path of the follower so that the axis itself is perpendicular to the direction of motion.
Wedge Camshaft type
Wedge camshafts have a wide base that is pointed at the end, and are characterized as the wide base. It is common for the followers to slide against the cam when they are being followed.
Flat-tappet Camshaft type
As the name implies, flat tappet camshafts are composed of flat cylinders that have a slight crown on their faces as well as a flat shape. There are several shapes and sizes of lobes that can be found in flat tappet cams. These lobes are tapered in the middle. Basically, the tappets are attached to the camshafts by means of lobes that are inserted into them. As the followers or lifters ride on the lobes, the following and lifting forces are created as a result of the tapered shape of the lobes.
It is possible to use a flat-tappet that is either solid or hydraulic, both types of flat tappets are available. There are various types of camshafts, including flat-tappet cams, and they are generally made up of steel, which makes them extremely lightweight, durable, and easier to maintain.
Cylindrical camshaft type
As well as cylindrical cams, barrel or drum cams are also referred to as cylindrical cams. There are different types of cams, but what is common among them all is that they are named after cylinders.
An indentation has been cut into the cylindrical cam surface in the shape of a groove. During the movement of the follower, the path of the groove tends to be followed. In order to drive a driven member, the cam’s axis is parallel to the direction of motion of the driving member.
Heart-shaped camshaft type
A heart-shaped body is characterized by its asymmetrical structure. There is a follower that follows the camshaft as it moves along the edge. A heart-shaped camshaft produces a continuous and uniform motion, which resembles the motion exhibited by a liquid. A solenoid is basically an electrical device that is used to wind a wire evenly in a form of a coil around a core.
Globoid Camshaft type
It is imperative to note that globoid camshafts have the same structure as conventional camshafts so that they will function as well. Only here, there is a difference in the shape of the cylindrical shape. This is replaced by a structure that is either convex or concave instead of cylindrical shape.
Conjugate Camshaft type
Conjugate camshafts consist of two rollers, each roller attached to a follower, and both rollers are constantly engaged at the same time. As a result, the roller tends to constrain the movement of each other, thereby removing the noise as a result. A camshaft of this type is typically used in applications where the amount of noise is tolerable or where it is not at all tolerated.
Various camshaft configuration
Below mentioned a few configurations of various camshafts:-
Single overhead Camshaft
Among all the types of camshafts on the market, this is the oldest type. It is characterized by the fact that every head has its own camshaft, just as the name implies. As a general rule, two valves are found per cylinder on single overhead camshaft engines. There is a need to check and adjust the timing belts on a regular basis in these engines, since if the timing belts are misaligned or damaged, they may break, causing major damage to the engine as a result.
Pushrod camshaft adjustments
These engines, also known as overhead valve camshafts (OVCs), are similar to overhead valve engines, in that they have valves located on top of the cylinder in the engine head. In this case, the camshaft is located just inside the engine block, in contrast with where the camshaft is located in the cylinder head.
The camshaft in a pushrod camshaft engine is driven by a gear chain that is connected to a chain drive. In this way, the whole configuration will be more reliable and there will be a lower chance of experiencing problems. A disadvantage of an OHV camshaft is that it limits the engine’s speed potential to a certain extent, which can be considered to be a drawback.
Double overhead camshaft adjustments
It is also called a twin-cam engine in this case and, as the name suggests, there is a camshaft in each bank of the engine. The overhead camshaft is a component that is often used in engines with cylinders that have more than four valves for each cylinder.
Double Overhead Camshaft (DOHC) engines have the advantage that they are capable of significantly boosting engine power, which is one of the biggest advantages of the DOHC engine. This is because there is the possibility of using more valves with a double overhead camshaft, and that is why it is quite simple. Consequently, this means that gas can flow more freely through the larger openings.
Can a Camshaft increase the power of your engine?
In order for the engine to generate power, a mixture of air and fuel must be properly mixed and pressed before being ignited in order to create combustion. In order to achieve a mixture richer in oxygen and a more powerful ignition, the camshaft needs to open and close the intake valve, and modifying it can achieve this.
The camshaft on the stock vehicle is meticulously engineered in order to provide optimum power, longevity, and fuel economy. Because a high-performance camshaft doesn’t change the amount of fuel sprayed into the cylinders as a standard camshaft does, a high-performance camshaft can only result in a much more increase in your engine’s power and stability.
Power increases are never-ending processes that need to be improved in order to get more power out of the engine. There is a good chance that the new camshaft will be bottlenecked by the fuel injectors. A good fuel injector is the first step, but you will also need a good valve in order to run it properly. Then you will need to replace those with better intake and exhaust manifolds so that you can provide and expel all the air you need. At the end of that process, you will be able to get enhanced horsepower. However, at that point, the question becomes whether it is even worth it to invest in such a large upgrade.
Possible causes for Camshaft damage
Below mentioned a few possible causes for your camshaft to get damaged:-
Lubrication of the lobes during installation is often the cause of wear because it is not done properly. Be sure to only use a lubricant that is recommended by the manufacturer, usually included with the cam itself. In order to maintain the smooth operation of flat tappet cams, it is necessary to apply lubricant to the surfaces of each cam lobe, as well as the bottom of each lifter face. Only the lifters and cams of roller tappet cams need to be oiled in order to function properly.
Improper lubricants for braking system
Once fresh, non-synthetic oil has been poured into the crankcase after the correct break-in lubricant has been applied to the cam and lifters, the engine can be started. Especially with flat tappet camshafts, you should use motor oil with a break-in additive for your engine after it has been tuned.
Make sure that the pushrods are turning while the lifters are being broken in, as doing so will show that the lifters are also turning as well. There will be problems with the cam lobes and lifters if the lifters do not rotate. The push rod may need to be spun a little bit by hand in order to start the rotation process, but this is not always the case.
Valves springs are under too much pressure
The correct height and pressure of the valve spring should always be verified before installing the valve springs. When a roller cam is used for racing, they have a high valve lift, and the spring pressure is high. This makes the cam less likely to splash oil onto the surface at low speeds, therefore it is not recommended for street use. Ensure that the height of the springs is the same as the manufacturer’s recommendation before assembling them.
An accident that results in a broken camshaft usually happens when a connecting rod or another rotating component comes loose and strikes the camshaft. As a result of rough handling during shipping, or improper handling prior to installation, it is quite common for your cam to break after a short period of use due to a broken part in a camshaft.
Possible Drawbacks of camshafts in a car
Below mentioned a few drawbacks of having camshafts in a car:-
- If you are looking to install a camshaft or repair an existing one, it can be quite expensive.
- An engine with a broken camshaft may suffer serious damage as a result of the damage that it has sustained.
Various Benefits of camshafts in a car
Below mentioned a few benefits of having camshafts in a car:-
- An engine’s camshaft is one of the most important components of an engine and is not difficult to understand when it comes to its design.
- A camshaft is responsible for enabling the proper flow of fuel and exhaust gases into and out of a combustion chamber.
- It is advantageous to use camshafts this way because they are capable of generating torque at both the low-end and at the high-end depending on the configuration.
- Many cylinders can be used with single camshafts.
- In addition to having a smooth surface, camshafts also have the advantage of maintaining their stability even with the great speeds they achieve.
- Maintenance of a camshaft is quite easy and it is quite durable too.
- Additionally, camshafts improve valve actuating mechanisms’ dynamic characteristics.