Combustion condition detecting apparatus for an internal combustion engine

• US 6,336,355 B1
• Filed: 02/01/2000
• Issued: 01/08/2002
• Est. Priority Date: 08/30/1999
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Sasaki, Shu, Okamura, Koichi, Nobe, Hisanori, Koiwa, Mitsuru, Hatazawa, Yasuyoshi
• Primary Examiner(s): MCCALL, ERIC SCOTT
• Application Number:
  US09/496,277
• Time in Patent Office: 707 Days
• Field of Search: 73/350.1, 73/350.3, 73/350.4, 73/350.6, 73/350.8, 73/350.7, 731/16, 731/172, 731/173, 731/181
• US Class Current: 73/35.08
• CPC Class Codes: F02B 77/08 Safety, indicating, or supervising devices thermal insulation F02B77/11; monitoring or diagnostic devices for exhaust-gas treatment apparatus F01N11/00
• CPC Class Codes: F02D 35/021 using an ionic current sensor
• CPC Class Codes: F02D 41/009 using means for generating position or synchronisation signals
• CPC Class Codes: F02P 17/12 Testing characteristics of the spark, ignition voltage or current testing of sparking plugs H01T13/60
• CPC Class Codes: F02P 2017/128 for knock detection
• CPC Class Codes: G01L 23/221 for detecting or indicating knocks in internal combustion engines
• CPC Class Codes: G01L 23/225 circuit arrangements therefor

Abstract

To provide a combustion condition detecting apparatus for an internal combustion engine, which may well detect the combustion conditions such as discrimination of a combustion cylinder and knock generating condition and may reduce a circuit scale therefor, there are provided an ignition coil 21 provided for each cylinder; an ignition plug 20 for discharging by the application of the ignition high tension voltage to ignite mixture within the cylinder; a bias circuit 1 provided for each cylinder for applying a bias voltage to the ignition plug 20; an ionic current detection circuit 2 provided for each cylinder for detecting as an ionic current detection signal an ionic current 6 generated in the cylinder that is immediately after the combustion of the mixture; a knock signal processing circuit 4 provided one for a combination of a plurality of cylinders that are every two or more cylinders in ignition order on the basis of a sum of the ionic current detection signals; and an ECU 5 for detecting the combustion condition of the ignition plug on the basis of the knock signal.

Claims

1. A combustion condition detecting apparatus for an internal combustion engine including a plurality of cylinders, comprising:

a plurality of ignition coils for generating an ignition high tension voltage, each of the ignition coils being provided for a corresponding one of the cylinders;

a plurality of ignition plugs connected to said ignition coils, each of the ignition plugs discharging in response to said ignition high tension voltage to ignite a mixture of fuel and air within a corresponding one of the cylinders of the internal combustion engine;

a plurality of bias circuits for applying a bias voltage to said ignition plugs;

a plurality of ionic current detection circuits connected to the bias circuits, each of the ion current detection circuits detecting an ionic current corresponding to an amount of ion generated in a corresponding cylinder immediately after the combustion of the mixture and generating an ionic current detection signal based on the detected ion current;

a plurality of knock signal processing circuits for generating knock signal for representing a knock generation condition of said internal combustion engine on the basis of a sum of said ionic current detection signals, each of said knock signal processing circuits being coupled to at least two of said ionic current detection circuits so that each of said knock signal processing circuits is provided for one cylinder in each of a plurality of groups of two or more of the cylinders in ignition order; and

an electronic control unit (ECU) coupled to said knock signal processing circuits for detecting the combustion condition of said ignition plug on the basis of said knock signals.

2. The combustion condition detecting apparatus for an internal combustion engine according to claim 1, further comprising a plurality of combustion signal processing circuits for generating combustion signals by comparing a sum of said ionic current detection signals with a predetermined detection level, each of said combustion signal processing circuits being coupled to at least two of said ionic current detection circuits provided for at least two of said cylinders which are not simultaneously ignited in a simultaneous ignition mode occurring immediately after a start of the internal combustion engine,

wherein said ECU receives said combustion signals from said combustion signal processing circuits, makes a cylinder discrimination and a combustion judgement on the basis of said combustion signal.

3. The combustion condition detecting apparatus for an internal combustion engine according to claim 2, wherein each of said ionic current detection circuits comprises a current mirror circuit.

4. A combustion condition detecting apparatus for an internal combustion engine including a plurality of cylinders, comprising:

a plurality of ignition coils for generating an ignition high tension voltage, each of the ignition coils being provided for a corresponding one of the cylinders;

a plurality of ignition plugs connected to said ignition coils, each of the ignition plugs discharging in response to said ignition high tension voltage to ignite a mixture of fuel and air within a corresponding one of the cylinders of the internal combustion engine;

a plurality of bias circuits for applying a bias voltage to said ignition plugs;

a plurality of ionic current detection circuits connected to the bias circuits, each of the ion current detection circuits detecting an ionic current corresponding to an amount of ion generated in a corresponding cylinder immediately after the combustion of the mixture and generating an ionic current detection signal based on the detected ion current;

a plurality of combustion signal processing circuits for generating combustion signals by comparing a sum of said ionic current detection signals with a predetermined detection level, each of said combustion signal processing circuits being coupled to at least two of said ionic current detection circuits provided for at least two of said cylinders which are not simultaneously ignited in a simultaneous ignition mode occurring immediately after a start of the internal combustion engine; and

an electronic control unit (ECU) connected to said combustion signal processing circuits for receiving said combustion signals, making a cylinder discrimination and a combustion judgment on the basis of said combustion signal.