What is the difference between camshaft and crankshaft?

 

The camshaft and crankshaft are two important parts of the engine, and they play a unique and vital role in the operation of the ENGINE. Since they are very similar, have you ever wondered what the difference is betweencrankshaft and camshaft? What role do they play in the operation of the engine?

 

Today's article will help you thoroughly understand the classic topic of crankshaft vs camshaft.

 

 

What is crankshaft?

 

What is a crankshaft? The crankshaft is one of the most important moving parts in an engine. Its job is to convert the linear motion of the piston into rotational motion, thereby outputting power. When the piston performs a power stroke, it oscillates within the engine cylinder. The connecting rod connects the piston to the crankshaft, allowing the piston to partially rotate on the downward motion and complete rotation on the upward motion. Converting reciprocating motion into rotational motion is a fundamental process in internal Combustion Engines.

 

Structural features of the crankshaft:

 

• Forged from high-strength alloy steel
• Main journal (connected to the engine cylinder block)
• Connecting rod journal (connected to the piston connecting rod)
• Counterweight (balances the rotational inertia force)

 

The crankshaft is usually located at the bottom of the engine. From the perspective of power output, the position of the crankshaft directly determines whether the engine can work efficiently and smoothly.

 

What is a camshaft?

 

The camshaft consists of multiple cam units designed to facilitate the intake and exhaust processes of the engine. When the piston reaches the top dead center of its stroke, the intake valve needs to open to allow air or air-fuel mixture to enter the cylinder. Conversely, when the piston contains exhaust gas, the exhaust valve needs to open to discharge the exhaust gas to the atmosphere. The camshaft ensures that these valves open precisely at the right time.

 

Structural features of the camshaft:

 

• Made of cast iron or steel
• With multiple cams (Cam lobes)
• May be equipped with a variable valve timing (VVT) system

 

The camshaft is usually located inside the cylinder head (overhead camshaft, OHC) or on the side of the cylinder block (side camshaft). On camshaft trucks, the camshafts are usually more robust and durable due to the high load demands of Diesel Engines.

 

 

What is the difference between crankshaft and camshaft?

 

Although both crankshafts and camshafts are the core rotating parts of the engine, they are significantly different in function, structure and location.

 

1. Different functions

lCrankshaft: responsible for power output and turning the wheels

lCamshaft: responsible for controlling the valves and affecting combustion efficiency

 

2. Different structures

lCrankshaft: thicker and more explosive

lCamshaft: more precise, the shape of the cam determines the valve motion curve

 

3. Different installation positions

lCrankshaft: located at the bottom of the engine (crankcase), connected to the piston.

lCamshaft: located at the top of the engine, close to the valve.

 

 

Difference between camshaft and crankshaft Summary comparison table

 

Characteristics	Camshaft	Crankshaft
Function	Controls valve opening/closing	Converts piston motion into rotational power
Location	Upper or middle part of the engine	Base of the engine
Period	In a four-stroke engine, it rotates once for every two revolutions of the crankshaft	Spins rapidly in sync with the pistons
Material	Made of cast iron, steel or alloy	Made of forged alloy steel
Failure effect	Failure of valve control will cause intake and exhaust disturbances	Power is interrupted and the engine is seriously damaged
Impact on performance	Camshaft design affects engine power, torque and efficiency by affecting valve timing and lift.	Crankshaft design affects the engine's balance, smoothness and ability to produce torque.

 

How do the crankshaft and camshaft work together?

 

Although the camshaft and crankshaft have different functions, they must work together to ensure that the engine runs as expected.

 

• The crankshaft receives the combustion work and generates rotational force;
• The camshaft is responsible for opening/closing the valves so that the cylinder can smoothly complete the intake and exhaust.

 

They are connected by a timing chain to ensure a precise mechanical rhythm to maintain synchronization. Once out of balance, it will cause misfire, reduced efficiency, and even damage the engine.

Summary

 

The crankshaft is like the "heart" of the engine, responsible for power output; while the camshaft is like the "brain", accurately controlling the operation of the valves. Understanding the difference between camshaft and crankshaft can help you better maintain the engine and even improve performance!

 

 

FAQ

 

1 Which is more likely to be damaged, the crankshaft or the camshaft?

The crankshaft is more durable, while the camshaft may wear out due to poor lubrication or timing system problems.

 

2. What is the difference between a truck camshaft (Camshaft Truck)?

Truck camshafts are larger and made of stronger materials. The design of Camshaft trucks also needs to meet the needs of long-term high-speed operation and frequent speed changes, so they are more wear-resistant and have higher processing accuracy.

 

3. Can a damaged crankshaft be repaired?

Yes, a damaged crankshaft can usually be repaired, but in severe cases, the crankshaft needs to be replaced.