Since the beginning of the internal combustion engine, the camshaft is one of the important components. Till this 21st century, its working principle is still the same in automobile engines.
Camshafts are simple component lengths of rod or shaft, having some individual cam lobes positioned along it. With these lobes, the shaft is called cams.
The shaft rotates allowing the shape of the cam to act upon a valve. It’s responsible for pushing against valves that open and close the compression and exhaust stroke. The speed of the rotation controls the rate of its actions.
Today we’ll be looking at the definition, working principle, making, parts, and problems of a camshaft in an automobile engine.
What is a Camshaft?
A camshaft consists of a cylindrical rod running the length of the cylinder bank. This camshaft working is achieved with a number of cams along its length. One lobe for each valve. These lobes force the valve to open by pressing on them.
Some intermediate mechanism is used for the valve closing. As the camshaft rotates, there are springs set in place to close the valve. This happens as the lobes reach their highest point on the push rod, which is when the valve is completely open. The spring pulls back the valve causing the valve to close.
This camshaft working principle is different from modern vehicles.
Modern internal combustion engines find camshafts useless in their work. Their calibration controls the amount of air-fuel mixture that enters the chamber. This air fuel enters at a precise level. After combustion, the exhaust gas exits the chamber making way for the next mixture.
This design doesn’t just affect the engine’s efficiency and operation. The movement of the engine piston is supposed to be perfectly synchronized with the opening and closing of the valves. It has a drastic effect on the vehicle’s performance.
The camshafts are connected through a timing belt or chain to ensure their timing and turning. It directly moves the pistons inside the cylinder. The working design of the camshaft lobes also controls the speed at which the valves open and close. Thus, this is the working principle of camshaft on modern engines.
The video below gives further explanation on the working of camshafts:
Camshafts are made from metal to obtain rigidity. Cast iron is used are it offers such strength, use for mass production. Chilled iron camshafts have good wear resistance as the chilling process hardens the material.
Some other elements are added to the iron before casting in order to obtain more suitable properties for its application.
Billet steel is used by manufacturers when high-quality and low-volume production is required. although it’s more time-consuming and expensive than other methods.
Its construction method is either forging, casting, or machining (metal lathe or milling machine). Different steel bars can be used.
Camshaft and Crankshaft Relationship
This two-drive system relationship, camshaft, and crankshaft rotation. Due to the fact that the valve controls the flow of the air/fuel mixture intake and exhaust gases. This valve is controlled by the camshaft for appropriate opening and closing timing during the piston stroke.
This is the reason why the camshaft is connected to the crankshaft, directly through a gear mechanism. It’s also connected indirectly via a belt or chain called a timing belt or timing chain. The direct mechanism process is unusual due to its cost.
Major parts of the camshaft
Below are the major camshaft parts:
Main Journals: The power produced by the camshaft comes from a constant rotation. The function of the journals is to keep the camshaft in place as it spins around the engine bay.
Lobes: as the spins, the lobes rotate together with the piston motion. The functions of the lobes are to open and close the valve for the intake and exhaust gases. The speed of the cam lobes depends on the engine’s speeds.
Ends: the front end of the cam is designed to carry a belt to connect with the crankshaft. The rear end of the cam turns the distributor of the engine with special gear. The ignition timing is in tune with the rest of the engine with this part.
Bearings: is mounted in conjunction with the main journals. It helps to prevent the camshaft from damaging the engine block when the engine becomes faulty. Bearings help to keep the rotation of the camshaft seamless.
Causes of camshaft failure and their prevention
There are several issues that can be developed on Camshaft. If issues are not noticed, it can cause the engine to completely break down. Below are the major causes of camshaft failure:
- Lobe wear.
- Improper break-in.
- Oil lifters with a new cam.
- Mechanical interference – occurs as the spring coil bind, the retainer to the seals, valve to the piston. interference, and rocker arm slot to stud interference.
- Broken cam.
- Excessive end play.
- Broken dowel pins or keys.
- Incorrect valve spring pressure.
Symptoms of a bad camshaft position sensor
The position sensor in a camshaft gives information on the camshaft condition. The information is sent to the vehicle’s engine control module (ECM). This ECM uses the data obtained to determine the timing of the ignition. It also noticed the fuel injection that the engine requires.
Thus, this sensor helps the engine to function properly. It also notifies the user about the condition of the engine due to the information received.
However, the camshaft positioning sensor can fail, weak, or become worn down. This might occur due to accidents or normal wear and tear. Below are the warning signs of a camshaft position sensor to take note of before it fails and damages the engine.
- The drive of the vehicle completely changes
- A vehicle might not even start
- The engine light needs to be checked
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- Symptoms Of a Bad Crankshaft Position Sensor
That’s it for this article “Camshaft working, parts, construction, problem, etc.” I hope the knowledge is attained, if so kindly comment, share, and recommend this site to other technical students. Thanks!