Cummins 6B 6BT

The engine cylinder head is an important part of the internal combustion engine. It is located at the top of the engine and forms a combustion chamber together with the cylinder block (cylinder block). It undertakes many key functions in the operation of the engine. The design and material selection directly affect the performance, efficiency and reliability of the engine.

1. The main function of the cylinder head

Sealing the combustion chamber

Cooperating with the cylinder gasket and the cylinder block to form a closed space to withstand the impact of high-temperature and high-pressure combustion gas.

Accommodating the valve mechanism

Install the intake valve, exhaust valve, valve spring, camshaft (overhead camshaft design) and other valve mechanism components.

Providing cooling and lubrication channels

The interior is designed with cooling water channels (connected to the engine cooling system) and oil channels for heat dissipation and lubrication.

Install auxiliary components

Spark plugs (gasoline engines), injectors (direct injection engines), preheat plugs (diesel engines), etc.

2. Structural characteristics of the cylinder head

Combustion chamber design

The shape affects the flow of the mixture and the combustion efficiency. Common types: hemispherical, wedge-shaped, basin-shaped, etc.

Airway design

The layout of the intake/exhaust duct affects the intake efficiency (such as vortex generation) and exhaust smoothness.

Multilayer structure

Integrated complex water channels, oil channels, and bolt holes require high-precision processing (such as CNC processing).

3. Common materials

Cast iron

Traditional materials (such as gray cast iron and ductile iron) are low in cost and heat-resistant, but heavy (mostly used in diesel engines).

Aluminum alloy

The mainstream choice of modern gasoline engines, lightweight and fast heat dissipation, but low high-temperature strength (requires enhanced design).

Composite materials

A few high-performance engines may use magnesium alloy or ceramic coating technology.

4. Manufacturing process

Casting

Sand mold casting or metal mold casting to form a blank.

Machining

High-precision milling and drilling (such as valve seat rings, camshaft holes).

Heat treatment

Eliminate internal stress or enhance surface hardness (such as aluminum alloy T6 heat treatment).

5. Common faults and repairs

Cylinder head deformation

Cause: overheating, uneven installation torque. Need to be milled and repaired or replaced.

Cracks

Caused by thermal stress or poor cooling, often near the valve seat, need to be welded or replaced.

Valve seat ring wear

Leading to poor valve sealing, need to be reamed or replaced.

Cylinder gasket ablation

Manifested as coolant seeping into the combustion chamber or oil emulsification, need to replace the cylinder gasket and check the cylinder head flatness.

6. Maintenance recommendations

Regularly check: coolant quality, oil status (to prevent oil channel blockage).

Standard installation: Tighten the cylinder head bolts in the manufacturer's torque sequence (to avoid deformation).

Avoid overheating: deal with cooling system failures in a timely manner (such as water pump, thermostat problems).

7.New technology trends

Integrated exhaust manifold

Integrated exhaust ducts in the cylinder head to speed up warm-up and reduce emissions.

3D printing technology

Used for prototype development or complex airway optimization.

Variable valve technology

The cylinder head needs to support variable valve timing/lift systems (such as VTEC, Valvetronic).