Method for igniting a fuel/air mixture, ignition system and glow plug

• US 9,534,575 B2
• Filed: 07/23/2014
• Issued: 01/03/2017
• Est. Priority Date: 07/31/2013
• Status: Active Grant

• Current Assignee: BorgWarner Ludwigsburg GmbH (BorgWarner Incorporated)
• Original Assignee: BorgWarner Ludwigsburg GmbH (BorgWarner Incorporated)
• Inventors: Eberhardt, Michael, Allgaier, Martin
• Primary Examiner(s): Moubry, Grant
• Application Number:
  US14/338,961
• Publication Number:
  US 20150034055A1
• Time in Patent Office: 895 Days
• Field of Search: 123/549, 123/179.6, 123/145.R, 123/145.A, 123/143.C, 123/169.R, 123/169.E, 123/169.P
• US Class Current: 1/1
• CPC Class Codes: F02M 31/125 Fuel
• CPC Class Codes: F02P 13/00 Sparking plugs structurally combined with other parts of internal-combustion engines connection of ignition coil to spark plug connector F02P3/02; with fuel injectors F02M57/06 ; spark plug connector per se H01T13/04 – H01T13/06; predominant aspects of sparking plug, see H01T13/40 – H01T13/44
• CPC Class Codes: F02P 19/02 electric, e.g. layout of circuits of apparatus having glowing plugs
• CPC Class Codes: F02P 19/028 the glow plug being combined with or used as a sensor
• CPC Class Codes: F02P 23/045 using electromagnetic microwaves
• CPC Class Codes: F23Q 2007/002 with sensing means
• CPC Class Codes: F23Q 7/001 Glowing plugs for internal-combustion engines

Abstract

What is described is a method for igniting a fuel/air mixture in a combustion chamber of an engine, wherein a pencil, which is electrically insulated with respect to walls of the combustion chamber and contains a heating resistor, is electrically heated to a temperature of at least 800° C. in the combustion chamber of the engine by applying a heating voltage, and a high voltage of at least 500 V, which is different from the heating voltage, is applied to the pencil and thereby ions are generated in the combustion chamber by field emission of electrons. The invention additionally relates to an ignition system and a glow plug.

Claims

1. A method for igniting a fuel/air mixture in a combustion chamber of an engine, comprising:

providing a pencil which is electrically insulated with respect to walls of the combustion chamber and contains a heating resistor;

applying a heating voltage to the heating resistor and thereby electrically heating the pencil to a temperature of at least 800°

C. in the combustion chamber of the engine; and

applying a high voltage of at least 500 V, which is different from the heating voltage, to the heating resistor and thereby generating ions in the combustion chamber by field emission of electrons.

2. The method according to claim 1 wherein the pencil is a ceramic pencil.

3. The method according to claim 1 wherein the high voltage is a high-frequency AC voltage.

4. The method according to claim 3 wherein the high-frequency AC voltage has a frequency of at least 10 kHz.

5. The method according to claim 1 wherein the high voltage is at least one hundred times higher than the heating voltage.

6. The method according to claim 1 wherein the pencil is electrically heated by applying DC voltage pulses of less than 25 V.

7. The method according to claim 6 wherein the high voltage is applied between the DC voltage pulses.

8. The method according to claim 7 wherein the heating voltage has an effective value of less than 10 V.