Since the beginning of internal combustion engine, camshaft is one of important component. Till this 21th century its working principle are still the same in automobile engines.
Camshafts are simple component length 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 camshaft in an automobile engine.
What is a Camshaft?
A camshaft consists of cylindrical rod running the length of the cylinder bank. This camshaft working is achieved with numbers 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 use for the valve closing. As the camshaft rotate, there are springs set in place to close the valve. This happens as the lobes reaches its highest point on the push rod, which when the valve is completely open. The spring pull back the valve causing the valve to close.
This camshaft working principle is different on modern vehicles.
Modern internal combustion engine find camshaft useless on its working. Their calibration controls the amount of air-fuel mixture that enters the chamber. This air-fuel enters at precise level. After combustion, the exhaust gas exits the chamber making way for the next mixture.
This design doesn’t just affect the engine efficiency and operation. The movement of the engine piston is supposed be perfectly synchronized for 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 its timing and turning. It directly moves the pistons inside the cylinder. The working design of the camshaft lobes also controls the speed which the valves open and close. Thus, this is the working principle of camshaft on modern engines.
Video below give further explanation on the working of camshafts:
Camshafts are made from metal to obtain rigidity. Cast iron is used are its 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 are 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, machining (metal lathe or milling machine). Different steel bar can be used.
Camshaft and Crankshaft Relationship
These two-drive system relationship, camshaft and crankshaft rotation. Due to the face that the valve controls the flow of the air/fuel mixture intake and exhaust gases. This valve which 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 timing belt or timing chain. The directly mechanism process is unusual due to its cost.
Major parts of 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.
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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 engines speeds.
Ends: the front end of the cam is designed to carry belt to connects with the crankshaft. The rear end of the cam turns the distributor of the engine with a special gear. The ignition timing in tune with the rest of the engine with this part.
Bearings: is a 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 camshaft seamless.
Causes of camshaft failure and their prevention
There are several issues that can be develop on camshaft. If is issues are not noticed, it can cause the engine to completely breakdown. Below are the major causes of camshaft failure:
- Lobe wear.
- Improper break-in.
- Oil lifters with a new cam.
- Mechanical interference – occurs as spring coil bind, retainer to seal, valve to 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 bad camshaft position sensor
The position sensor in a camshaft gives information on the camshaft condition. The information is send 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 accident or normal wear and tear. Below are the warning signs of a camshaft position sensor to take note before it fails and damage the engine.
- The drive of the vehicle completely changes
- Vehicle might not even start
- Engine light need to be checked
That’s it for this articles “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!