Spark plug fouling detection for ignition system

Patent metadata

Field	Value
Publication number	US-9835128-B2
Application number	US-201715615552-A
Country	US
Kind code	B2
Filing date	Jun 6, 2017
Priority date	Oct 17, 2013
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

A method for determining a level of spark plug fouling and providing an indication to change the spark plugs of an ignition system is provided. The method includes providing a dwell command on a control wire of an ignition system and generating an indication of a recommendation to change a spark plug of the ignition system based upon a current on the control wire.

First claim

The invention claimed is:

1. A system for determining a level of spark plug fouling and pre-ignition, the system comprising:
an ignition coil for an ignition system, the ignition coil including a primary winding and a secondary winding;
a spark plug connected to a high voltage terminal of the secondary winding;
a first battery connected to a low voltage terminal of the secondary winding;
a feed-forward diode with sensing resistor network connected between the low voltage terminal and the battery;
a comparator receiving input from a reference voltage and a sensed voltage tap connected to the feed-forward diode, where the reference voltage is a voltage set ratio-metrically between a second battery and ground;
a logic OR gate receiving input from the comparator and controlling a switch;
a first current sink connected between a control wire and ground while the switch is closed;
a second current sink connected between the control wire and ground; and
a controller configured to execute non-transitory instructions to:
provide a dwell command on the control wire of an ignition system; and
generate an indication of a recommendation to change a spark plug of the ignition system when a current on the control wire drops below a predetermined value after a threshold period of time has elapsed after the dwell command is provided, the current on the control wire measured via a current sensor.

2. The system of claim 1 , further comprising a first resistor and a second resistor connected across the feed-forward diode.

3. The system of claim 2 , wherein the first resistor and the second resistor are connected in series.

4. The system of claim 3 , wherein the first resistor and the second resistor are connected in parallel.

5. The system of claim 1 , further comprising an input tap coupled to the control wire, where the input tap is positioned between the first resistor and the second resistor.

6. The system of claim 5 , wherein the input tap provides the sensed voltage tap to the comparator.

7. The system of claim 1 , where the first battery is a vehicle battery.

Assignees

• Ford Global Tech Llc

Inventors

• Huberts Garlan J
• Qu Qiuping

Classifications

• F02P3/0453

  Opening or closing the primary coil circuit with semiconductor devices · CPC title

• H01T13/60

  of electrical properties · CPC title

• F02P17/12 Primary

  Testing characteristics of the spark, ignition voltage or current (testing of sparking plugs H01T13/60) · CPC title