Bypass control apparatus for turbocharged internal-combustion engines

Claim 1

In a bypass control apparatus for turbocharged internal-combustion engines having an opening characteristic dependent upon the boost pressure and for a bypass valve arranged in a bypass line which connects a point of a boost air pipe located downstream of a compressor to a point of an exhaust gas pipe located upstream of the turbine inlet of the turbocharger, the improvement which comprises: a fluid circuit containing a fluid source for a pressurized fluid medium; an actuating cylinder for actuating the bypass valve; said actuating cylinder being loadable by the pressurized fluid medium; said fluid circuit comprising a supply line; a throttle valve having fixedly adjustable throttle cross-section arranged in said supply line between the fluid source and the actuating cylinder; control throttle means arranged downstream of the actuating cylinder in the flow direction of the fluid medium; resilient means for loading said control throttle means; said control throttle means comprising two closure elements defining first and second closure elements; a control air line branching off said boost air pipe; piston means for actuating said two closure elements by boost air pressure; and said resilient means in a rest condition maintaining the first closure element open and the second closure element closed.