upper pressure chamber 10 through the cover of the cylinder a spiral spring 62 acts in a valve spring chamber 66 on a spring plate which is connected to the valve shank 5 in the event of faults in a limited number of engine valves the relevant cylinder u2014 or else plurality of cylinders u2014 may be partially shut down and the pistons moved passively an emergency running program with mechanical restoration of engine valves 2 into a rest state is therefore provided in the rest state the fluid in the high pressure system can be discharged by means of a brief opening of all the fluid valves the engine valves 2 are guided by means of said springs 62 into their upper position in order that servicing and repairs can be carried out in the unpressur u00b1 zed state the valves do not come into contact with the pistons of the engine when said pistons are in the vicinity of top dead center the cylinder head when removed from the engine block may be put down in the installed position without the risk of damage the mounting and dismounting of the valve drive are thereby considerably simplified fluid which passes into the valve spring chamber 66 through the upper valve guide 60 at the transition from the upper pressure chamber 10 to said valve spring chamber 66 is conducted through an opening into the unpressurized base reservoir p 0 in a second exemplary embodiment according to fig2 the engine fuel is used as fluid and the first pressure reservoir p 2 serves as an intermediate stage for the.