Exhaust Manifold

Exhaust Manifold is a core component of the internal combustion engine exhaust system, and also one of the key automotive pipe fitting products of JIATIAN. As the first-stage component of the exhaust system, Exhaust Manifold is directly mounted on the cylinder head’s exhaust port, and Exhaust Manifold undertakes the critical task of collecting and guiding high-temperature and high-pressure combustion gases from each cylinder to the subsequent exhaust pipeline, which is vital to the engine’s exhaust efficiency and overall performance.

1. Exhaust Manifold Working Principle

Gas Collection: During the exhaust stroke of each cylinder, the exhaust valve opens, and the high-temperature (up to 800-1000℃) and high-pressure combustion waste gas enters the corresponding branch pipe of the exhaust manifold through the exhaust port.
Uniform Convergence: The manifold’s multi-branch pipe design (matching the number of engine cylinders) guides gases from different cylinders to a single main outlet, avoiding mutual interference between exhaust pulses of adjacent cylinders to ensure smooth exhaust.
Thermal Adaptation: JIATIAN’s exhaust manifold adopts special material and structural design to withstand continuous thermal expansion and contraction during engine operation, preventing gas leakage and structural deformation.

2. Product Core Performance?

JIATIAN’s exhaust manifold products fully embody the company’s technical advantages in automotive pipe fittings: relying on 800T hydraulic water expansion machines and water expansion corrugated pipe core technology (leading in the industry), the internal flow channel of the manifold is more smooth, further improving exhaust efficiency while ensuring structural strength.

3. Application Cases

• Commercial Vehicle Field: It is applied to a 3.0L diesel engine of a domestic heavy-duty truck brand. In the high-load operation scenario of long-distance transportation (continuous operation for 12 hours a day), the manifold maintains structural integrity without thermal fatigue failure, and the exhaust back pressure is stably controlled within 12kPa, effectively ensuring the engine’s power output and fuel economy.
• Passenger Vehicle Field: It is equipped with a 1.5T turbocharged engine of a joint-venture passenger vehicle. In urban stop-and-go working conditions, the optimized NVH design of the manifold reduces the in-car exhaust noise by 10dB compared with the original configuration, and the user’s driving comfort feedback is excellent.

4. FAQ About Exhaust Manifold

1. Q: What is the key factor affecting the service life of exhaust manifold?
   A: The main influencing factors are material high-temperature resistance and thermal cycle resistance, as well as welding process reliability. JIATIAN’s exhaust manifold selects high-performance stainless steel and uses brazing furnace and laser welding technology for overall molding, which can extend the service life to more than 150,000km (equivalent to the engine’s whole life cycle) under normal use conditions.
2. Q: Can the exhaust manifold be replaced and modified by itself?
   A: It is not recommended to replace or modify it without professional guidance. The installation position and angle of JIATIAN’s exhaust manifold are precisely calibrated according to the engine model. Improper modification will lead to increased exhaust back pressure, reduced engine power, or even damage to the three-way catalytic converter. The company provides professional matching and installation guidance services for cooperative customers.
3. 
   Q: How to judge whether the exhaust manifold has failed?
   A: Common failure manifestations include exhaust port gas leakage (accompanied by abnormal noise), local deformation of the flange, and increased exhaust back pressure (leading to engine power drop). JIATIAN’s comprehensive laboratory can provide professional failure detection and analysis services for customers.

5. Maintenance Guidance of Exhaust Manifold

1. Regular Inspection Cycle:
   • For passenger vehicles: Inspect the manifold flange sealing and welding seams every 20,000km;
   • For commercial vehicles: Inspect every 10,000km (due to higher load), focusing on checking for cracks and loose fasteners.
2. Maintenance Key Points:
   • When disassembling and assembling, use torque wrenches to lock the flange bolts according to the specified torque (generally 25-35N·m, subject to the vehicle maintenance manual) to avoid flange deformation caused by uneven force;
   • Avoid washing the engine compartment with high-pressure water immediately after the vehicle is shut down (high-temperature manifold encounters cold water will cause thermal shock and cracks);
   • If the sealing gasket is aged, replace it with the original accessories provided by JIATIAN in time to prevent exhaust leakage.
3. Abnormal Handling:
   Once abnormal noise or gas leakage is found, stop using it and contact JIATIAN’s after-sales technical team in time. The company’s professional engineers will provide on-site or remote troubleshooting guidance according to the failure phenomenon.
   
   

6. Comparison with Similar Products (Exhaust Manifold vs. Exhaust Header)