Patent ID: 7762236

Claim:
A fuel injector, comprising: a housing having a sealable injector seat; a fuel injector pin disposed within the housing proximate to the injector seat such that the injector seat may be sealed and unsealed by displacing the fuel injector pin; a resilient element biasing the fuel injector pin in an unsealed direction; a piezoelectric actuator disposed within the housing proximal to the fuel injector pin configured to actuate to force the injector pin towards the injector seat to seal the injector seat; and a thermal compensating unit disposed within the housing proximal to the actuator and configured to compensate for thermal expansion or contraction of a component of the fuel injector, wherein the thermal compensating unit comprises a fluid chamber in fluid communication with a fluid source and is configured to compensate for thermal expansion or contraction of the component by viscous dampening or hydraulic pressure, wherein the thermal compensating unit further comprises a second resilient element configured to provide a biasing force on the actuator towards the injector seat, wherein the thermal compensating unit further comprises a thermal compensator disposed within the housing to transfer force from the resilient element and fluid chamber to the actuator, wherein the fluid source comprises a fuel source, wherein the fuel injector further comprises a fuel chamber disposed within the housing and in fluid communication with the fuel source and wherein the fuel injector is configured such that the fuel in the fluid chamber has substantially equal pressure as fuel in the fuel chamber prior to fuel injection, wherein the fuel in the fuel chamber is heated prior to fuel injection and the fuel in the fluid chamber is maintained at the substantially the same pressure as the fuel in the fuel chamber during the heating.