Piezoelectric injector for direct fuel injection

An internal combustion engine comprising:

• at least one combustion chamber
• one or more piezo injectors for direct fuel injection into the at least one combustion chamber, each piezo injector comprising:
• an injector body,
• an actuator unit having a piezoelectric actuator with a head plate and a base plate,
• a hydraulic coupler having a coupler piston, a coupler cylinder, and a coupler spring, and
• a nozzle unit having a nozzle needle arranged in a nozzle body,
• wherein the coupler cylinder is formed in the base plate of the piezoelectric actuator,
• wherein the piezoelectric actuator is surrounded by a corrugated tube braced between the head plate and the base plate such that the piezoelectric actuator has a preload imparted to it,
• wherein the coupler spring forces the coupler piston against a face side, facing toward the coupler piston, of the nozzle needle.