US Patent No. 7,896,257, Fuel injector with real-time feedback control
The patent US 7,896,257is about a fuel injection apparatus with a piston device that includes a channel and a piston in the channel. A position sensor is used to detect the piston movement inside the channel when the fuel injection apparatus is energized and de-energized, and the sensing value is used for controlling fuel injection rate in real-time and diagnosing failures in the apparatus. With an actuator installed, the piston can also be used for independently modulating fuel pressure during fuel injection. Thereby the shape of fuel injection pulses is controlled. The fuel injection apparatus has three injection states, and flexible fuel injection timing and multi-pulse injection are allowed. Furthermore, in all injection states, fuel supply has no direct contact to combustion chamber. As a result, when a malfunction sticks the apparatus open, no fuel is supplied. This feature provides a safety nature to the fuel injection apparatus.
Uniqueness and benefits of this technology
1. A unique metering process is introduced in a common-rail injector;
2. In the metering process, fuel flow rate is measured directly for individual injectors;
3. Fuel flow rate is used in real-time fueling rate or air-fuel ratio feedback control;
4. Injector issues and injection system issues can be diagnosed directly with flow rate sensing;
5. Fueling pulse shape can be controlled in the metering process;
6. A safety nature in the processing process stops fuel supply when nozzle is stuck open.