Dual fuel injection valve and method of operating a dual fuel injection valve

The present invention relates to a hydraulically actuable dual fuel injection valve and a dual needle assembly, for injecting two different fuels into the combustion chamber of an internal combustion engine. A dual fuel injection valve separately and independently injects two different fuels into a combustion chamber of an internal combustion engine. A first fuel is delivered to the injection valve at injection pressure and a second fuel is either raised to injection pressure by an intensifier provided within the injection valve, or delivered to the injection valve at injection pressure. Electronically controlled valves control hydraulic pressure in control chambers disposed within the injection valve. The pressure of the hydraulic fluid in these control chambers is employed to independently actuate a hollow outer needle that controls the injection of the first fuel. Disposed within the outer needle is an inner needle that controls the injection of the second fuel. The outer needle closes against a seat associated with the injection valve body and the inner needle closes against a seat associated with the outer needle.