Patent ID: 7513230

Claim:
A camshaft adjusting system for an internal combustion engine, the camshaft adjusting system comprising: a camshaft adjusting device with a first hydraulic chamber and a second hydraulic chamber, wherein the first and second hydraulic chambers act in opposition to one another; a control valve group working as a 4/4-way valve system and comprising a first connection to the first hydraulic chamber, a second connection to the second hydraulic chamber, a tank connection, and a connection for pressurization, wherein the control valve group has only a first state, a second state, a third state, and a fourth state; wherein the camshaft adjusting system in the first state of the control valve group, when starting the internal combustion engine, is pressure-relieved relative to the tank connection by simultaneously hydraulically connecting the first and second connections of the camshaft adjusting device so that the camshaft adjusting device moves into a dwell position with a single locking mechanism and said dwell position also provides a safety function in case of system failure, which dwell position is selected automatically and independently of the process of switching off the internal combustion engine.