Fluid injector

Patent metadata

Field	Value
Publication number	US-9757748-B2
Application number	US-201314425126-A
Country	US
Kind code	B2
Filing date	Jul 30, 2013
Priority date	Sep 26, 2012
Publication date	Sep 12, 2017
Grant date	Sep 12, 2017

Abstract

A fluid injector comprising a coil arranged to drive a pump from a first state to a second state when energized, so as to pump a dosing fluid; a PN junction electrically arranged across the coil to discharge energy stored in the coil when the voltage across the coil is above a threshold. In one particular embodiment, the fluid injector is a selective catalytic reduction dosing fluid injector.

First claim

The invention claimed is:

1. A fluid injector for a selective catalytic reduction dosing system comprising:
a coil arranged to drive a pump from a first state to a second state when energized, so as to pump and inject a fluid;
a PN junction electrically arranged across the coil to breakdown and discharge energy stored in the coil when an external drive voltage is removed from the coil, and when a voltage across the coil is above a breakdown voltage of the PN junction, and wherein the PN junction and the coil share a cooling system.

2. The fluid injector of claim 1 wherein the PN junction is within a diode electrically arranged across the coil.

3. The fluid injector of claim 1 wherein the PN junction is within a transient voltage suppressor electrically arranged across the coil.

4. The fluid injector of claim 1 wherein the PN junction is directly connected to the coil.

5. The fluid injector of claim 4 wherein the PN junction is soldered to terminals of the coil.

6. The fluid injector of claim 1 wherein the PN junction and the coil are within a common cooling jacket.

7. The fluid injector of claim 1 wherein the selective catalytic reduction dosing system comprises a diagnostic circuit configured to diagnose the satisfactory operation of the PN junction, wherein the diagnostic circuit is arranged to measure a current decay or a voltage delay during discharge of the coil.

8. The fluid injector of claim 1 wherein the fluid injector is one of a selective catalytic reduction dosing injector, a fuel injector and a water injector.

9. A method of discharging a coil of a fluid injector, the method comprising:
supplying a coil of the fluid injector with electrical energy to drive a pump from a first state to a second state so as to pump and inject a fluid;
stopping the supply of electrical energy to the coil; and
allowing the electrical energy stored in the coil to dissipate through a PN junction electrically arranged across the coil and wherein the PN junction and the coil share a cooling system.

Assignees

• Delphi Int Operations Luxembourg Sarl
• Delphia Int Operations Luxembourg S A R L

Inventors

• Sykes Martin A P
• Mitchel Alasdair
• Smith Nick

Classifications

• F01N2610/11

  the substance or part of the dosing system being cooled · CPC title

• F02D41/221

  relating to the failure of actuators or electrically driven elements · CPC title

• Y02T10/24

  Cross-Sectional Technologies · mapped topic

• F02D2041/2058

  using information of the actual current value · CPC title

• F01N3/2066

  Selective catalytic reduction [SCR] · CPC title