Ignition device and ignition method for internal combustion engine

Patent metadata

Field	Value
Publication number	US-2016348596-A1
Application number	US-201415116667-A
Country	US
Kind code	A1
Filing date	Feb 17, 2014
Priority date	Feb 17, 2014
Publication date	Dec 1, 2016
Grant date	—

Abstract

An ignition unit of an internal combustion engine is equipped with an ignition coil including a primary coil and a secondary coil, an igniter, and a secondary current detection resistor. By means of the secondary current detection resistor, an engine controller detects a current value of the secondary current immediately after completion of capacitive discharge. The current value of the secondary current is correlated with a gas pressure between electrodes of a spark plug at ignition timing, and thus an in-cylinder pressure at the ignition timing can be estimated from the current value. An amount of time-dependent change in compression ratio, caused by accumulation of deposits, is calculated based on the in-cylinder pressure at the ignition timing.

First claim

What is claimed is:

1 . An ignition device for an internal combustion engine in which a discharge voltage is generated between electrodes of a spark plug connected to a secondary coil by energizing a primary current to a primary coil of an ignition coil and interrupting the primary current, comprising:
a secondary current detection means for monitoring a secondary current flowing across the electrodes; and an in-cylinder pressure estimation means for estimating an in-cylinder pressure at ignition timing based on the secondary current, wherein the in-cylinder pressure estimation means is configured to estimate the in-cylinder pressure at the ignition timing based on a current value of the secondary current immediately after completion of capacitive discharge.

2 . (canceled)

3 . The ignition device for the internal combustion engine as recited in claim 1 , wherein:
a current value of the secondary current detected when a predetermined time has expired from the ignition timing is used as the current value of the secondary current immediately after completion of capacitive discharge.

4 . An ignition device for an internal combustion engine in which a discharge voltage is generated between electrodes of a spark plug connected to a secondary coil by energizing a primary current to a primary coil of an ignition coil and interrupting the primary current, comprising:
a secondary current detection means for monitoring a secondary current flowing across the electrodes; and an in-cylinder pressure estimation means for estimating an in-cylinder pressure at ignition timing based on the secondary current, wherein the in-cylinder pressure estimation means is configured to estimate the in-cylinder pressure at the ignition timing based on a discharge duration during which the secondary current flows.

5 . The ignition device for the internal combustion engine as recited in claim 4 , wherein:
a time duration during which the secondary current above a predetermined threshold value flows is detected as the discharge duration.

6 . The ignition device for the internal combustion engine as recited in claim 1 , which further comprises:
a compression ratio estimation means for calculating a compression ratio at the ignition timing of an associated cylinder based on the estimated in-cylinder pressure.

7 . The ignition device for the internal combustion engine as recited in claim 6 , which further comprises:
a compression ratio diagnostic means for comparing the calculated compression ratio with a reference compression ratio corresponding to the ignition timing.

8 . The ignition device for the internal combustion engine as recited in claim 1 , wherein:
the in-cylinder pressure is estimated for each individual cylinder in a multi-cylinder internal combustion engine, for determining a dispersion in in-cylinder pressure of each of the cylinders.

9 . The ignition device for the internal combustion engine as recited in claim 1 , wherein:
the in-cylinder pressure is estimated under a specified operating condition of the internal combustion engine where an intake pressure is high and the ignition timing is set near a top dead center position.

10 . An ignition method for an internal combustion engine in which a discharge voltage is generated between electrodes of a spark plug connected to a secondary coil by energizing a primary current to a primary coil of an ignition coil and interrupting the primary current, the ignition method comprising:
monitoring a secondary current flowing across the electrodes; and estimating an in-cylinder pressure at ignition timing based on a current value of the secondary current immediately after completion of capacitive discharge.

11 . An ignition method for an internal combustion engine in which a discharge voltage is generated between electrodes of a spark plug connected to a secondary coil by energizing a primary current to a primary coil of an ignition coil and interrupting the primary current, the ignition method comprising:
monitoring a secondary current flowing across the electrodes; and estimating an in-cylinder pressure at ignition timing based on a discharge duration during which the secondary current flows.

12 . The ignition device for the internal combustion engine as recited in claim 4 , which further comprises:
a compression ratio estimation means for calculating a compression ratio at the ignition timing of an associated cylinder based on the estimated in-cylinder pressure.

13 . The ignition device for the internal combustion engine as recited in claim 4 , wherein:
the in-cylinder pressure is estimated for each individual cylinder in a multi-cylinder internal combustion engine, for determining a dispersion in in-cylinder pressure of each of the cylinders.

14 . The ignition device for the internal combustion engine as recited in claim 4 , wherein:
the in-cylinder pressure is estimated under a specified operating condition of the internal combustion engine where an intake pressure is high and the ignition timing is set near a top dead center position.

Assignees

• Nissan Motor

Inventors

• Shiraishi Taisuke

Classifications

• F02D35/024 Primary

  using an estimation · CPC title

• F02P3/0407

  Opening or closing the primary coil circuit with electronic switching means (F02P3/045 - F02P3/055 take precedence) · CPC title

• F02D41/22

  Safety or indicating devices for abnormal conditions {(in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809)} · CPC title

• F02P17/12

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