| Quantity: | |
|---|---|
| Feature | Part Number 4995554 | Part Number 4994143 |
|---|---|---|
| Part Name | Intake Valve | Exhaust Valve |
| Material | High-strength alloy steel, often with chrome or nitride coating for wear resistance | High-strength alloy steel |
| Compatibility | DCEC 4B, 6B, 4BT3.9, 6BT5.9, and B5.9 engines | DCEC 4B, 6B, 4BT3.9, 6BT5.9, and B5.9 engines |
| Applications | Construction machinery, agricultural equipment, marine vessels, heavy-duty trucks, generator sets | Construction machinery, agricultural equipment, marine vessels, heavy-duty trucks, generator sets |
| Function | Regulates the flow of fresh air into the combustion chamber | Responsible for releasing exhaust gases from the combustion chamber |
| Alternative P/N | 3901117, 3920867, 3802355 | 3901607, 3920868 |
 | |
Detailed Core Functions:
1. Precise Control of Airflow (Most Direct Function): Intake Valve (4995554): Opens during the piston's downward stroke (intake stroke), allowing fresh air (only pure air is drawn in in diesel engines) or a mixture into the cylinder; closes during the compression, power, and exhaust strokes, ensuring the cylinder's seal.
Exhaust Valve (4994143): Opens during the piston's upward stroke (exhaust stroke), expelling combusted exhaust gases from the cylinder; closes during the intake, compression, and power strokes, ensuring the combustion chamber's seal.
2. Ensuring Combustion Chamber Seal (Most Critical Function): During the compression stroke (piston compresses air) and the power stroke (fuel is injected and explodes to generate power), both valves must close tightly simultaneously to ensure a completely sealed combustion chamber.
If the seal is not tight: it will lead to air leakage, pressure drop, severe power loss, and even failure to start. This is the cornerstone of valve operation.
3. Optimizing Engine Performance and Efficiency: Valve design (size, material, opening angle) directly affects the engine's "breathing" efficiency (i.e., intake efficiency and exhaust smoothness).
Efficient intake: Helps to draw in sufficient air, ensuring complete combustion of diesel fuel.
Efficient exhaust: Helps to quickly expel exhaust gases, reducing pumping losses and improving engine thermal efficiency and power output.
4. Adapting to High Temperature and High Pressure Environments: As components in one of the harshest environments inside the engine, their core functions also include withstanding extreme high temperature, high pressure, and high-speed reciprocating motion:
Exhaust valves need to withstand combustion temperatures exceeding 1000°C and enormous pressure shocks.
Both intake and exhaust valves require extremely high wear resistance, fatigue resistance, and mechanical strength.
