Piezoelectric Injector for Direct Fuel Injection

Patent metadata

Field	Value
Publication number	US-2016245247-A1
Application number	US-201415024521-A
Country	US
Kind code	A1
Filing date	Sep 19, 2014
Priority date	Sep 25, 2013
Publication date	Aug 25, 2016
Grant date	—

Abstract

A piezo injector for direct fuel injection may comprise 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. 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. The coupler spring forces the coupler piston against a face side, facing toward the coupler piston, of the nozzle needle.

First claim

What is claimed is:

1 . A piezo injector for direct fuel injection, the piezo injector comprising:
an injector body, an actuator unit having a piezoelectric actuator with a head plate and with a base plate, 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, 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 spring forces the coupler piston against a face side, facing toward the coupler piston, of the nozzle needle.

2 . The piezo injector as claimed in claim 1 ,
wherein the corrugated tube comprises a maraging steel.

3 . The piezo injector as claimed in claim 1 ,
wherein the coupler cylinder is formed in the base plate of the piezoelectric actuator.

4 . The piezo injector as claimed in claim 1 ,
wherein the piezo injector does not comprise any sealing material composed of a plastic.

5 . The piezo injector as claimed in claim 1 ,
wherein the injector body is a unipartite tube piece fixedly connected at one side to the head plate and at an opposite side to the nozzle body.

6 . The piezo injector as claimed in claim 1 ,
wherein the nozzle needle opens outwardly.

7 . The piezo injector as claimed in claim 1 ,
wherein the nozzle unit has a nozzle spring for generating a closing force which acts on the nozzle needle.

8 . The piezo injector as claimed in claim 7 ,
wherein the nozzle spring, at one side, is fastened to the nozzle body and, at the other side, presses against a spring plate which is attached to the nozzle needle.

9 . The piezo injector as claimed in claim 1 ,
wherein a fuel film is arranged in the hydraulic coupler.

10 . The piezo injector as claimed in claim 9 ,
wherein the fuel film has a thickness in the range from 0.05 mm to 0.3 mm.

11 . 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 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.

12 . The internal combustion engine as claimed in claim 11 , wherein the corrugated tube comprises a maraging steel.

13 . The internal combustion engine as claimed in claim 11 , wherein the coupler cylinder is formed in the base plate of the piezoelectric actuator.

14 . The internal combustion engine as claimed in claim 11 , wherein the piezo injector does not comprise any sealing material composed of a plastic.

15 . The internal combustion engine as claimed in claim 11 , wherein the injector body is a unipartite tube piece fixedly connected at one side to the head plate and at an opposite side to the nozzle body.

16 . The internal combustion engine as claimed in claim 11 , wherein the nozzle needle opens outwardly.

17 . The internal combustion engine as claimed in claim 11 , wherein the nozzle unit has a nozzle spring for generating a closing force which acts on the nozzle needle.

18 . The internal combustion engine as claimed in claim 17 , wherein the nozzle spring, at one side, is fastened to the nozzle body and, at the other side, presses against a spring plate which is attached to the nozzle needle.

19 . The internal combustion engine as claimed in claim 11 , wherein a fuel film is arranged in the hydraulic coupler.

20 . The internal combustion engine as claimed in claim 19 , wherein the fuel film has a thickness in the range from 0.05 mm to 0.3 mm.

Assignees

• Continental Automotive Gmbh

Inventors

• Schuerz Willibald

Classifications

• F02M61/14

  Arrangements of injectors with respect to engines; Mounting of injectors · CPC title

• F02M51/0603 Primary

  using piezoelectric or magnetostrictive operating means · CPC title

• F02M61/08

  the valves opening in direction of fuel flow {(F02M61/047 takes precedence)} · CPC title

• F02M2200/26

  Fuel-injection apparatus with elastically deformable elements other than coil springs · CPC title

• F02M2200/708

  with hydraulic chambers formed by a movable sleeve · CPC title