Here's a breakdown:
What it is:
* A rotating shaft: The camshaft is a long, cylindrical shaft located in the engine block, typically driven by the crankshaft.
* With "cams" on it: Along the camshaft are "lobes" or "cams," which are shaped bumps that rise and fall as the shaft rotates.
* Opening and closing valves: These cams interact with valve lifters (or tappets) and pushrods, which ultimately push on the valves to open them at specific times.
What it does:
* Controls the engine's breathing: The timing of the intake and exhaust valves directly impacts how much air and fuel enter the cylinders and when the exhaust gases are released.
* Determines performance: The camshaft profile (shape of the lobes) dictates the duration and timing of the valves. This influences factors like:
* Power: Aggressive cam profiles can give more power, but can also lead to less fuel efficiency.
* Torque: Cams can be designed to provide more torque at lower RPMs, which is useful for towing or driving in stop-and-go traffic.
* Idle quality: Mild cam profiles can provide smoother idling.
* Engine noise: More aggressive cam profiles can create a louder, more performance-oriented exhaust note.
Different types:
* Single cam: A single camshaft controls both the intake and exhaust valves on one side of the engine.
* Dual cam: Two camshafts are used, one for the intake valves and one for the exhaust valves. This provides more precise control and often results in better performance.
* Overhead cam (OHC): The camshaft is located above the valves in the cylinder head, making for a more compact engine design.
* Overhead camshaft (SOHC): A single overhead camshaft controls both intake and exhaust valves.
* Dual overhead camshaft (DOHC): Two overhead camshafts, one for intake and one for exhaust valves, allowing for more precise valve control.
In summary:
The camshaft is a crucial part of the engine, essentially acting as the "brain" that controls the timing and duration of the valves. By understanding how it works, you can gain insight into how different cam profiles affect the performance of your car.
