Valve Mechanism and Gear System of Diesel Generator

I'm sure that many purchasing personnel in various units aren't particularly clear about and familiar with the in - depth details of diesel generator sets, especially the valve train and gear system in their basic structures. Today, the generator knowledge class will share relevant knowledge about the valve train and gear system.

The valve mechanism consists of a valve group and a valve drive group. The valve group includes valves, valve springs, valve lock clips, valve oil seals, valve guides, valve spring upper seats, and rotating washers. The valve drive group includes the camshaft, tappets, valve push - rod components, rocker arm shaft supports, valve rocker arm assemblies, camshaft timing gears, valve bridges and other parts. The lubrication of the valve mechanism is achieved by guiding oil from the oil holes in the cylinder block and cylinder head to the rocker arm shaft supports, then to the rocker arm shaft holes. Part of the lubricating oil is sprayed onto the valve bridges and push - rod sockets, flows to the tappets, and then returns to the oil pan.

1 - Cylinder head machining assembly (cylinder head, intake valve seat, exhaust valve seat, valve guide, bowl - shaped plug)

2 - Exhaust valve

3 - Rotating washer

4 - Valve oil seal

5 - Exhaust valve spring

6 - Exhaust valve spring seat

7 - Intake valve spring

8 - Valve spring upper seat

9 - Valve lock clip

10 - Intake valve

The camshaft has a fully - supported top - mounted structure. The left and right rows of camshafts are divided into sections for three cylinders each and are connected in the middle with bolts. Carefully install the camshaft into the engine block, taking care not to damage the surfaces of the journal, cam, and bushing. Install the spacer ring, camshaft thrust plate, camshaft timing gear, and washer, and tighten the locking bolts. The tightening torque is 90 - 110 (N·m). The camshaft should rotate freely. The camshaft timing gear is positioned by a locating pin and is fastened to the end face of the camshaft with four M8 bolts. The axial clearance of the camshaft is controlled by the thrust plate, and its value is 0.10 - 0.25mm.

A special valve spring disassembly and assembly tool should be used when disassembling and assembling the valve springs.

To ensure the performance, after the valve guide is pressed into the cylinder head, the height from its upper end face to the rotating washer is required to be 22 ± 0.2mm. The intake valve seat ring with a 119° cone angle matches the intake valve with a 120° cone angle, and the exhaust valve seat ring with a 90° cone angle matches the exhaust valve with a 90° cone angle, which provides good sealing and performance. After the valves are installed in the cylinder head, the valves and valve seats must be lapped.

The valve recession should be strictly controlled: the intake valve recession is - 0.09 - 0.26mm, and the exhaust valve recession is - 0.13 - 0.22mm.

To ensure the normal operation of the diesel generator, users should regularly check and adjust the valve clearance as required. If the intake valve clearance is too large, the valve opening will be insufficient, reducing the charging efficiency and affecting the power. If it is too small, it will affect the valve sealing or cause the valve to collide with the piston crown. In the cold state, the intake valve clearance is 0.6 ± 0.05mm, and the exhaust valve clearance is 0.65 ± 0.05mm.

The gear system adopts a front - mounted gear chamber structure. The gears are designed using patented meshing gears, which can reduce contact stress and effectively improve contact fatigue strength, achieving the goal of effective noise reduction. The large gear is an assembly composed of one large and one small gear. The large and small gears are press - fitted together. The oil pump gear and fuel transfer pump gear do not require timing marks.

The other gears are all helical gears and have timing marks. The timing marks on the small idler gear can be seen through the circular hole in the large idler gear. During assembly, the assembly marks must be aligned to avoid affecting the performance or even causing damage to the parts.

The meshing clearance between the small idler gear and other gears can also be detected through the circular hole in the large idler gear. The required backlash for all gears is 0.07 - 0.35mm.

Dingbo Power was founded in 1974 and is one of the earliest manufacturers of generators and diesel generator sets in China. If you want get more information, please feel free to send email to [email protected] we will pay highly attention on your question.