Ignition device

Patent metadata

Field	Value
Publication number	US-9897062-B2
Application number	US-201415039857-A
Country	US
Kind code	B2
Filing date	Nov 28, 2014
Priority date	Nov 28, 2013
Publication date	Feb 20, 2018
Grant date	Feb 20, 2018

Abstract

An ignition device at least equipped with a DC power source, an ignition coil unit, a spark plug, an ignition switch, and an auxiliary power source, wherein the auxiliary power source is at least equipped with a discharge energy accumulating means, a discharge switch, and a discharge driver. The ignition device is further equipped with a secondary-current feedback controlling means comprising a secondary current detecting means for detecting a secondary current flowing during the ignition coil unit discharge period, and a secondary current feedback control circuit-for determining an upper limit and a lower limit for the secondary current from binary threshold values, and driving so as to open and close the discharge switch on the basis of the determination results. Furthermore, energy is introduced from the auxiliary power source without switching the polarity of the secondary current.

First claim

What is claimed is:

1. An ignition device, comprising:
a direct-current power source;
an ignition coil unit including a primary coil and secondary coil, an electric current through the primary coil being increased and decreased by interrupting the electric current from the direct-power source, thereby generating a high voltage in the secondary coil;
an ignition switch switching between supply of and interrupt of the electric current to the primary coil according to an ignition signal, the ignition signal being sent according to an operating condition;
an ignition plug connected to the secondary plug and generating electric sparks due to spark discharge caused by the high voltage applied from the secondary coil; and
an auxiliary power source superimposing electric energy on a downstream side of the primary coil after start of the spark discharge from the ignition plug,
the auxiliary power source including a discharge energy accumulating means, a discharge switch, a discharge driver turning and a secondary current feedback controlling means,
the discharge energy accumulating means being for accumulating electric energy from the direct-current power source,
the discharge switch switching between allowing discharge and stopping discharge from the discharge accumulating means,
the discharge driver turning the discharge switch,
the secondary current feedback controlling means including a secondary current detecting means and a secondary current feedback controlling circuit, the secondary current detecting means being for detecting the secondary current flowing through the secondary coil during the discharge period from the ignition coil unit, the secondary current feedback controlling circuit turning the discharge switch on the basis of the secondary current detected by the secondary current detecting means,
the ignition device allowing the auxiliary power source to input energy without reversing the polarity of the secondary current.

2. The ignition device according to claim 1 , wherein
the secondary current feedback controlling means includes a secondary current feedback controlling circuit judging an upper limit and a lower limit of a secondary current on the basis of two thresholds, the secondary current being detected by the secondary current detecting means, and turning the discharge switch on the basis of the judgement result.

3. The ignition device according to claim 2 , wherein
the secondary current detecting means outputs a secondary current detection voltage which is the secondary current converted into voltage, and
the secondary current feedback controlling circuit includes a comparator and judges the secondary current detection voltage with a predetermined upper limit voltage or a predetermined lower limit voltage by means of the comparator, the comparator comparing the secondary current detection voltage with the upper limit voltage when the secondary current is rising, and with the lower limit voltage when the secondary current is falling.

4. The ignition device according to claim 1 wherein the secondary current feedback controlling means detects occurrence of discharge blow-off on the basis of the secondary current, aside from the secondary current feedback controlling circuit.

5. The ignition device according to claim 4 , wherein the secondary current feedback controlling means includes the secondary current feedback controlling circuit, a secondary current command value calculating means for calculating a secondary current target value as a target, according to operating condition of an internal combustion engine, and a secondary current learning means for correcting the secondary current target value as a target, depending on whether the discharge blow-off has occurred.

6. The ignition device according to claim 5 , comprising a discharge blow-off detecting means for detecting whether discharge blow-off has occurred, and sending a discharge blow-off signal.

7. The ignition device according to claim 6 , wherein:
the secondary current command value calculating means sets a predetermined secondary current basis command value according to operating condition of an internal combustion engine, and sets an initial value of a secondary current correction learning value;
the secondary current learning means determines whether blow-off has occurred by comparing the secondary current with a blow-off current threshold, increases the correction learning value when it is determined that blow-off has occurred, and decreases the correction learning value when it is determined that combustion state is stable without occurrence of blow-off; and
the secondary current command value calculating means inputs a sum of the basis command value and the correction learning value, as a new secondary current command value, to the secondary current feedback controlling circuit to perform feedback control wherein the secondary current command value is used as a secondary current target value.

8. The ignition device according to claim 6 , wherein the discharge blow-off detecting means includes a malfunction determining means for determining malfunction which has occurred in any one of the ignition coil unit, the ignition switch and the auxiliary power source by comparing a first secondary current and a second secondary current with a first delay time current threshold and a second delay time current threshold, respectively, the first secondary current being the secondary current at the time when a predetermined first delay time elapses from the falling edge of the ignition signal, the second secondary current being the secondary current at the time when a predetermined second delay time elapses from the falling edge of the ignition signal.

9. The ignition device according to claim 8 , wherein
the malfunction determining means at least comprises steps of:
determining that the ignition coil unit, the ignition switch and the auxiliary power source re normal, if the secondary current is the first delay time current threshold or more and the second delay time current threshold or more;
determining that the auxiliary power source has some malfunction, if the secondary current is the first delay time current threshold or more and below the second delay time current threshold; and
determining that the ignition coil unit or the ignition switch has some malfunction, if the secondary current is below the first delay time current threshold.

10. The ignition device according to claim 8 , wherein:
the discharge blow-off detecting means includes an auxiliary energy necessity determining means for determining necessity of input of energy from the auxiliary power source; and
if the auxiliary energy necessity determining means has determined input of energy from the auxiliary power source is unnecessary, the discharge blow-off detecting means determines that malfunction has occurred in either the ignition coil unit or the ignition switch by comparing a third secondary current with a third delay time current threshold, the third secondary current being the secondary current at the time when a predetermined third delay time elapses from the falling edge of the ignition signal.

11. The ignition device according to claim 8 , comprising a secondary voltage detecting means for detecting a secondary voltage,
the malfunction determining means compares the secondary voltage with a predetermined smoldering determination voltage threshold and a predetermined resistance anomaly voltage threshold, determines occurrence of smoldering if a period during which the secondary voltage is below the smoldering determination voltage threshold is longer than a predetermined period, determines occurrence of resistance anomaly if a perio

Assignees

• Denso Corp

Inventors

• Nakayama Satoru
• Toriyama Makoto
• Sugiura Akimitsu
• Ishitani Masahiro
• Mizutani Atsuya
• Andoh Kouji
• Hayashi Naoto
• Doi Kaori

Classifications

• F02P15/10 Primary

  having continuous electric sparks · CPC title

• F02P5/145

  using electrical means · CPC title

• F02P9/002

  Control of spark intensity, intensifying, lengthening, suppression (by means of current control in the storage devices F02P3/05, F02P3/09, during starting F02P15/12) · CPC title

• F02P3/05

  for control of the magnitude of the current in the ignition coil (during starting F02P15/12) · CPC title

• F02P5/15

  Digital data processing · CPC title