Valve Train, Basic Function - GF05.30-P-1000A

ENGINE ALL (CAR) 

Valve train, shown on engine 608 

Valve train, shown on engine 260 

Overview 

This document contains information on:

• General 
• Function 

General 

The valve train regulates gas exchange and charge change in the combustion chambers. Valve timing has considerable influence on the torque, output and emissions of the combustion engine.

function 

The valve train controls the mechanical closing and opening of the valves during charge change. A charge change means that exhaust gases are fed into the exhaust system and the combustion chambers are filled with fresh air. Valve opening and closing takes place by means of a rotating camshaft with overhead valves. The intake and exhaust valves can be operated via a common camshaft or separate intake and exhaust camshafts. Here, the camshafts are driven by the crankshaft. Camshaft positioners and valve lift switchover types are used for variable control of the valves.

A timing chain or toothed belt is used for power transmission. Power is transmitted between camshafts and valves by means of a valve actuation using a hydraulic tappet or roller-type cam follower.

There are two or four valves per cylinder in the cylinder head. If there is an odd number of valves, the number of intake valves is greater. As hollow poppet valves, the valves can result in improved thermal conduction amongst other things. The valves can be arranged parallel or turned. Therefore, variants of the valve train are defined via the control, operation and arrangement of the valves.

	Additional basic functions
	Cylinder head, basic function		GF01.30-P-1000A
	Valve timing, basic function	Engine 260 Engine 282 in model 177 with code 936 (Cylinder cut-out system)	GF05.00-P-1001A
	Camshaft, basic function		GF05.20-P-1000A