The invention aims to provide an accumulator piezoelectric
injector with a variable injection rule. The accumulator piezoelectric
injector with the variable injection rule comprises a pressurized control valve part, a three-stage
piston assembly, an injection control valve part, and a
needle valve part. The accumulator piezoelectric
injector with the variable injection rule adopts a pressurized control valve structure to control the pressurized area of a three-stage
piston, different pressurized ratios can be effectively achieved, thus the injection rule is more flexible. The operating processof a
needle valve is driven by a piezoelectric reactor, the response speed of the
needle valve is high, the freedom degree of controlling is large, and the injection rule is flexible and controllable, thus the
power performance and fuel economy of a
diesel engine are effectively improved, and more stringent emission regulations can be met through the
diesel engine; in addition, pressure fluctuation caused by
fuel injection can be slowed down by a pressure accumulation cavity, accurate control of the fuel-injection quantity is facilitated, and especially for the control accuracy of small amount of
oil can be significantly improved; and the pressure stabilizing effect of the pressure accumulation cavity reduces the size of a
common rail pipe, thus the service life of the
common rail pipe isprolonged.