초록 ▼

A fuel injector employs at least one sensing device for sensing changes in the thermodynamic properties of the fuel within the injector to thereby monitor injector performance during usage. In some embodiments, advantageously placed temperature sensors are employed to detect the release of thermal e

A fuel injector employs at least one sensing device for sensing changes in the thermodynamic properties of the fuel within the injector to thereby monitor injector performance during usage. In some embodiments, advantageously placed temperature sensors are employed to detect the release of thermal energy which occurs when the potential energy of a fuel at high-pressure is suddenly converted into kinetic energy by lowering the pressure of the fuel. Other embodiments of the instant invention employ advantageously placed pressure sensors to detect sudden changes in fuel pressure which occur during the course of the injection cycle. Whereas the sensing devices of the instant invention can be placed at a variety of locations, they are preferably placed to detect changes in the thermodynamic properties of the fuel flowing within an injector where such changes are appreciably large during injector usage. Preferably, injectors of the instant invention are compatible with microprocessor-based fuel-injection control systems to maintain near-ideal injector performance.

대표청구항 ▼

[ What is claimed is:] [12.] A method of controlling a fuel injector of the type used to inject fuel into a cylinder of an internal combustion engine when the injector is installed therein, the engine having a high-pressure fuel supply which delivers fuel to the injector, a low-pressure return which

[ What is claimed is:] [12.] A method of controlling a fuel injector of the type used to inject fuel into a cylinder of an internal combustion engine when the injector is installed therein, the engine having a high-pressure fuel supply which delivers fuel to the injector, a low-pressure return which removes fuel from the injector and an electronic control unit for sending, receiving and processing control signals related to injector operation, the injector having a variable-volume control chamber in selective fluid communication with the high-pressure fuel supply and the low-pressure fuel return, the injector also having a needle valve assembly disposed within the injector for movement between an injection-blocking position wherein fuel is not permitted to flow from the high-pressure fuel supply into the engine cylinder, and an injection-permitting position wherein fuel is permitted to flow from the high-pressure fuel supply into the engine cylinder, the needle movement being dependent on the fuel flow through the control chamber, the injector also having a valve for selectively establishing fluid communication between the control chamber and at least one of the high-pressure fuel supply and the low-pressure fuel return, said method comprising the steps of:sending an injector control signal to the injector from the electronic control unit;sensing at least one thermodynamic property of the fuel within at least one portion of the injector to produce a fuel flow signal commensurate with fuel-flow at the one portion;transmitting the fuel-flow signal to the electronic control unit;receiving the fuel-flow signal at the electronic control unit;comparing the injector control signal with the fuel-flow signal; andsending an error correction signal to the injector if the injector control signal differs from the fuel-flow signal by more than a predetermined amount.