JP2009222018A - Internal combustion engine abnormality diagnosis device, and abnormality diagnosis method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an abnormality diagnosis device for an internal combustion engine, capable of easily specifying the cause for abnormality in an operation state of an internal combustion engine, and provide an abnormality diagnosis method using the same. <P>SOLUTION: The abnormality diagnosis device classifies injection states of fuel injection valves on respective cylinders based on results of classification of the injection states of the fuel injection valves to "no problem", "probable", and "highly probable" concerning items of engine rotation fluctuation, fuel injection valve injection quantity correction quantity, and OBD accidental fire judging hysteresis. The abnormality diagnosis device classifies compression states in the cylinders to "no problem", "probable", and "highly probable" based on cylinder internal pressure detected by pressure sensors. The abnormality diagnosis device displays the results of diagnosis of injection defective of the fuel injection valves in the respective cylinders, and result of diagnosis of compression lowering in the cylinders on a monitor. Results of diagnosis displayed on the monitor are compared, and whether the cause for abnormality in operation states of the internal combustion engine is injection defective in the fuel injection valve or compression lowering in the cylinder is specified. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an internal combustion engine abnormality diagnosis device for diagnosing the cause of abnormality in the operating state of an internal combustion engine and an abnormality diagnosis method using the same.

2. Description of the Related Art Conventionally, a technique for detecting an abnormality in an operating state of an internal combustion engine due to misfire or the like based on engine rotation fluctuation is known (see, for example, Patent Documents 1 and 2).
However, in Patent Documents 1 and 2, although misfire of the internal combustion engine can be detected and the misfire cylinder can be identified, the cause of misfire cannot be identified.

  Here, the cause of the abnormality in the operating state of the internal combustion engine is considered to be either an injection failure of the fuel injection valve or a reduction in compression in the cylinder. The injection failure of the fuel injection valve is caused by, for example, a non-injection state of fuel injection or a shortage of injection amount due to foreign matter biting into the sliding portion. Further, the compression reduction in the cylinder is caused by wear of the piston ring or defective seat of the intake valve or the exhaust valve.

Therefore, if an abnormality occurs in the operating state of the internal combustion engine due to misfire or the like, for example, in a dealer, referring to the vehicle diagnosis manual, the fuel injection valve injection diagnosis result by OBD (On-Board Diagnosis) Diagnosing the cause of abnormality in the operating state based on the diagnosis of the in-cylinder pressure with a pressure sensor attached to the mounting hole instead of the glow plug.
JP-A-5-195858 JP 2001-241353 A

  However, in the diagnosis with reference to the diagnosis manual, it is difficult to specify whether the cause of the abnormality in the operating state is an injection failure of the fuel injection valve or a reduction in compression in the cylinder. As a result, there arises a problem that, for example, a normal fuel injection valve that does not need to be replaced is replaced in order to eliminate the abnormality in the operating state.

  The present invention has been made to solve the above-described problem, and an object of the present invention is to provide an internal combustion engine abnormality diagnosis device that can easily identify the cause of abnormality in the operating state of the internal combustion engine, and an abnormality diagnosis method using the same. To do.

  According to the invention described in claims 1 to 7, the injection state classifying unit classifies the abnormal state of the injection failure of the fuel injection valve into a plurality of levels based on the injection state of the fuel injection valve, and the compression state classification unit includes: Based on the compression state in the cylinder, the abnormal state of the compression decrease in the cylinder is classified into a plurality of levels.

  Thus, by classifying the abnormal state of poor injection of the fuel injection valve and the abnormal state of compression reduction in the cylinder into a plurality of levels, the cause of the abnormal operating state is determined from the level of each abnormal state. It is possible to easily identify whether the injection failure of the valve or the compression reduction in the cylinder.

  For example, if the abnormal state of the fuel injection valve injection failure is worse than the abnormal compression reduction state in the cylinder based on the classified abnormality level, the operating state abnormality cause is the fuel injection valve injection failure Can be identified.

According to the second aspect of the invention, the classification result of the injection state classification unit and the classification result of the compression state classification unit are displayed on the display unit.
Thereby, the diagnostic operator can visually recognize the injection state of the fuel injection valve of each cylinder and the compression state in the cylinder. Thereby, based on the classification result displayed on the display means, it is possible to easily identify and replace an abnormal part or device of the fuel injection valve, the piston ring, the intake / exhaust valve, or the like.

  By the way, the abnormal state of the injection failure of the fuel injection valve can be easily classified based on the rotational fluctuation of the internal combustion engine, the injection amount correction amount, and the misfire determination history. The misfire determination history is history information of a misfire cylinder diagnosed by OBD.

  Therefore, according to the third aspect of the invention, the injection state acquisition means acquires the rotation fluctuation, the injection amount correction amount, and the misfire determination history as the injection state of the fuel injection valve. As a result, the injection state classification means can easily classify the abnormality of the injection failure of the fuel injection valve into a plurality of light to heavy levels based on the rotation fluctuation, the injection amount correction amount, and the misfire determination history.

According to a fourth aspect of the present invention, the compression state classification means classifies the abnormality in the compression reduction into a plurality of levels from light to heavy based on the cylinder pressure detected by the pressure sensor.
Thereby, based on the cylinder internal pressure detected by the pressure sensor, the compression state in the cylinder can be determined with high accuracy. As a result, it is possible to classify the abnormality in compression reduction with a high accuracy from a plurality of light to heavy levels.

  According to the fifth aspect of the present invention, the compression state obtaining means stops the injection of the fuel injection valve after the injection state classification means classifies the abnormality of the injection failure of the fuel injection valve into a plurality of levels, and performs motor drive. The internal combustion engine is rotated to acquire the compression state in the cylinder.

Thereby, the compression state in a cylinder can be acquired with high precision in the state which excluded the influence of the fuel injection from a fuel injection valve.
According to the sixth aspect of the present invention, when the compression state acquisition means acquires the compression state in the cylinder of the internal combustion engine, a pressure sensor is attached to the glow plug mounting hole by removing the glow plug installed in each cylinder of the internal combustion engine. Install.

  As described above, by attaching the pressure sensor using the attachment hole of the glow plug, the compression state in the cylinder can be detected with high accuracy even when the pressure sensor for detecting the cylinder internal pressure is not installed in the cylinder.

  By the way, the classification result by the injection state classification means and the classification result by the compression state classification means are compared, and when the abnormal state is the same level in the cylinder, the cause of the abnormal operation state is due to the injection failure of the fuel injection valve. It is difficult to determine whether it is due to a reduction in compression in the cylinder or not only by the classification result of the abnormality diagnosis device.

  Therefore, according to the seventh aspect of the invention, the classification result by the injection state classification means and the classification result by the compression state classification means are compared, and when the abnormal state is the same level, the abnormality diagnosis device drives the fuel injection valve. After the engine is stopped, the cause of abnormality in the operating state of the internal combustion engine is diagnosed by manual diagnosis.

  As a result, when the classification result by the injection state classification means and the classification result by the compression state classification means are at the same level, the fuel injection valve drive is stopped and the diagnosis by the abnormality diagnosis device is terminated, and the diagnosis manual or the like is referred to. However, the cause of the abnormality can be diagnosed in detail manually.

  The functions of the plurality of means provided in the present invention are realized by hardware resources whose functions are specified by the configuration itself, hardware resources whose functions are specified by a program, or a combination thereof. The functions of the plurality of means are not limited to those realized by hardware resources that are physically independent of each other.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a fuel supply system in which an abnormality diagnosis device of the present invention diagnoses an abnormality.
(Fuel supply system 10)
The fuel supply system 10 of this embodiment is for supplying fuel to, for example, a four-cylinder diesel engine (hereinafter also simply referred to as “engine”) 2 for an automobile, and supplies fuel to the common rail 20. A high-pressure pump 16, a common rail 20 that stores high-pressure fuel, a fuel injection valve 30 that injects high-pressure fuel supplied from the common rail 20 into the combustion chamber of each cylinder 4 of the engine 2, and an electronic control device that controls the system (Electronic Control Unit (ECU) 40. The fuel supply system 10 includes a feed pump 14 that pumps fuel from the fuel tank 12 in order to supply fuel from the high-pressure pump 16 to the common rail 20.

  The high-pressure pump 16 as a fuel supply pump is a known pump that pressurizes the fuel sucked into the pressurizing chamber by reciprocating the plunger as the camshaft cam rotates. The metering valve 18 serving as a metering actuator is installed on the suction side of the high-pressure pump 16 and controls the amount of fuel sucked by the high-pressure pump 16 during the suction stroke by current control. Then, by adjusting the fuel intake amount, the fuel discharge amount of the high-pressure pump 16 is adjusted.

  The common rail 20 is provided with a pressure sensor 22 for detecting the internal fuel pressure (common rail pressure), and a pressure reducing valve 24 for reducing the internal fuel pressure by overflowing the internal fuel to the fuel tank 12 side. Yes.

  A glow plug 6 is attached to the upper part of each cylinder 4 of the engine 2. Further, the engine 2 is provided with a rotation speed sensor 32 that detects the rotation speed of the engine 2 as a sensor that detects the operating state. The output signal of the rotation speed sensor 32 is used not only to detect the engine rotation speed but also to detect the rotation angle position of the crankshaft.

  Further, as other sensors for detecting the driving state, an accelerator sensor for detecting an accelerator opening ACCP that is an operation amount of the accelerator pedal, a temperature for detecting the temperature of the cooling water (water temperature), and the temperature of the intake air (intake air temperature). Sensors and the like are provided in the fuel supply system 10.

The fuel injection valve 30 is, for example, a known electromagnetic valve that controls the lift of the nozzle needle that opens and closes the nozzle hole with the pressure in the control chamber.
The ECU 40 is configured by a microcomputer centered on a CPU, ROM, RAM, flash memory, and the like. And ECU40 takes in a detection signal from various sensors including pressure sensor 22, a crank angle sensor, and an accelerator sensor, and controls an engine operating state. For example, the ECU 40 controls the discharge amount of the high-pressure pump 16, the fuel injection amount of the fuel injection valve 30, the fuel injection timing, and the multistage injection pattern in which pilot injection, post injection, etc. are performed before and after the main injection.

  The abnormality diagnosis device 50 includes a processing unit 52 and a monitor 54. The processing unit 52 includes a CPU, ROM, RAM, flash memory, HD (Hard Disk), and the like. As the abnormality diagnosis device 50, a general-purpose personal computer may be used, or a dedicated device for diagnosis may be used.

  The abnormality diagnosis device 50 is connected to a predetermined connector of a vehicle at a dealer or the like when an abnormality in an operation state such as misfire occurs in the engine 2. Then, the abnormality diagnosis device 50 acquires data on the operating state of the engine 2 from the ECU 40 in an interactive manner with the abnormality diagnosis operator, and instructs the ECU 40 to perform processing necessary for abnormality diagnosis, and performs abnormality diagnosis processing. To do.

The abnormality diagnosis device 50 may acquire data on the operating state of the engine 2 from a sensor or the like instead of from the ECU 40.
The abnormality diagnosis device 50 displays, for example, an abnormal state of the injection failure of the fuel injection valve 30 in each cylinder 4 and an abnormal state of the compression decrease in the cylinder 4 in the form as shown in FIG. Displayed on a monitor 54. In FIG. 2A, no problem represents normal, probeable represents a mild abnormality, and high probeable represents a severe abnormality. In the present embodiment, the abnormal state is classified into two levels: probable and high probable. The diagnosis operator identifies an abnormal part or an abnormal device based on the diagnosis result displayed on the monitor 54 and performs necessary treatment.

The abnormality diagnosis apparatus 50 functions as the following units according to the control program stored in the HD.
(Injection state acquisition means)
The abnormality diagnosis device 50 determines whether the fuel injection valve 30 is in an injection state (A) rotational fluctuation, (B) injection amount correction amount, (C) OBD as an injection state of the fuel injection valve 30 in the idle operation state at the time of abnormality diagnosis when the vehicle is stopped. Get misfire judgment history.

(A) Rotational Fluctuation For example, the ECU 40 obtains the rotational speed difference between the maximum rotational speed and the minimum rotational speed in each cylinder, and calculates the difference between the average rotational speed difference of all the cylinders and the rotational speed difference of each cylinder as the rotational fluctuation ΔNE. Calculate as Abnormality diagnosis device 50 acquires rotation fluctuation ΔNE calculated by ECU 40.

(B) Injection amount correction amount The ECU 40 calculates an injection amount correction amount L for correcting the injection amount of the fuel injection valve 30 based on the rotation variation ΔNE in order to smooth the rotation variation between the cylinders. The abnormality diagnosis device 50 acquires the injection amount correction amount L of the fuel injection valve 30 of each cylinder 4 calculated by the ECU 40.

(C) OBD Misfire Determination History During operation of the engine 2, the ECU 40 performs misfire determination of each cylinder by OBD based on, for example, rotational fluctuation of the engine 2. The OBD misfire determination is stored in the flash memory or the like of the ECU 40 as a history. As a result, the abnormality diagnosis device 50 detects the misfire determination history of each cylinder even if the non-injection state of the fuel injection valve 30 is eliminated by removing a foreign object that has been caught in the past after the misfire, for example. Can be obtained from

(Injection state classification means)
As shown in FIG. 2B, the abnormality diagnosis device 50 determines the injection state of the fuel injection valve 30 for each item of (A) rotational fluctuation, (B) injection amount correction amount, and (C) OBD misfire determination history. Are classified into no probable, proble, and high probable.

(A) Rotational fluctuation The abnormality diagnosis device 50 sets a predetermined value N1 as a threshold value for classifying the injection state of the fuel injection valve 30 into no probable or probable with respect to the rotational fluctuation ΔNE, and classifies it into probable or high probable. A predetermined value N2 is set as the threshold value. N1 <N2.

  The abnormality diagnosis device 50 classifies as no problem when (rotational fluctuation ΔNE) <(predetermined value N1), and classifies as problematic when (predetermined value N1) ≦ (rotational fluctuation ΔNE) ≦ (predetermined value N2). , (Predetermined value N2) <(rotational fluctuation ΔNE), it is classified as high probeable.

(B) Injection amount correction amount The abnormality diagnosis apparatus 50 sets a predetermined value L1 as a threshold value to classify the injection state of the fuel injection valve 30 with respect to the injection amount correction amount L into no probable or probable, and sets probable or high probable. A predetermined value L2 is set as a threshold value for classification. L1 <L2.

  The abnormality diagnosis device 50 classifies as no problem when (injection amount correction amount L) <(predetermined value L1), and when (predetermined value L1) ≦ (injection amount correction amount L) ≦ (predetermined value L2), It is classified as probable, and when (predetermined value L2) <(injection amount correction amount L), it is classified as high probable.

(C) OBD misfire determination history The abnormality diagnosis device 50 classifies as no problem when there is no misfire in the past and there is no DTC (Diagnostic Trouble Code), and classifies as proble when there is a misfire and DTC in the past. If it is still misfired and there is DTC, it is classified as high probable.

  Then, the abnormality diagnosis device 50 determines that the injection state of the fuel injection valve 30 is no if the classification results of (A) rotational fluctuation, (B) injection amount correction amount, and (C) OBD misfire determination history are all no problems. Classify into problems.

  In addition, the abnormality diagnosis apparatus 50 does not have high probable for (A) rotational fluctuation, (B) injection amount correction amount, and (C) OBD misfire determination history classification result, but if even one probable exists, fuel injection The injection state of the valve 30 is classified as probable.

  Further, the abnormality diagnosis apparatus 50 determines that the injection state of the fuel injection valve 30 is present when at least one high probeable exists for the classification results of (A) rotational fluctuation, (B) injection amount correction amount, and (C) OBD misfire determination history. Is classified as a high probe.

(Compression state acquisition means)
In order to acquire the compression state in the cylinder 4, the diagnostic operator attaches a pressure sensor to the attachment hole of the glow plug 6 instead of the glow plug 6. The abnormality diagnosis device 50 acquires the cylinder pressure C detected by the ECU 40 from the output signal of the pressure sensor as the compression state in the cylinder 4 in a state where the injection of the fuel injection valve 30 is stopped and the starter motor is rotated.

By stopping the injection of the fuel injection valve 30, the abnormality diagnosis device 50 can diagnose the compression state in the cylinder 4 in a state where the influence of the combustion in the cylinder 4 is excluded.
(Compression state classification means)
The abnormality diagnosis device 50 classifies no problem, probeable, and high probe as shown in (C) of FIG.

  The abnormality diagnosis device 50 sets a predetermined value C1 as a threshold value to classify the compression state in the cylinder with respect to the cylinder internal pressure C as no probable or probable, and sets a predetermined value C3 as a threshold value to classify into the probable or high probable is doing. C3 <C1.

  If (predetermined value C1) ≦ (in-cylinder pressure C) ≦ (predetermined value C2), the abnormality diagnosis device 50 classifies the problem as no problem, and (predetermined value C3) ≦ (in-cylinder pressure C) ≦ (predetermined value L1). In this case, it is classified as probable, and when (cylinder internal pressure C) <(predetermined value C3), it is classified as high probable.

When (predetermined value C2) <(in-cylinder pressure C), the compression is not over-compressed but over-compressed. In this case, the abnormality diagnosis device 50 displays overcompression on the monitor 54 in another format.
(Display means)
The abnormality diagnosis device 50 diagnoses the abnormal state of the injection failure of the fuel injection valve 30 in each cylinder 4 and the abnormal state of the compression decrease in the cylinder 4 and displays the result on the monitor 54. 2 and 3, the abnormality diagnosis apparatus 50 may display the no problem, the probe, and the high probe in different colors.

(Abnormal diagnosis)
Next, the abnormality diagnosis of the engine 2 will be described based on the abnormality diagnosis routines shown in the flowcharts of FIGS. 4 to 7, “S” represents a step. The routine of FIG. 4 is executed by the diagnostic operator in an interactive manner with the abnormality diagnosis device 50.

(Error diagnosis main routine)
In S300 of FIG. 4, the diagnostic operator connects the abnormality diagnosis device 50 to a predetermined connector of the vehicle.

  The diagnosis operator starts the engine 2 before the abnormality diagnosis device 50 performs abnormality diagnosis of the fuel injection valve 30 in S302. Thereby, when the abnormality diagnosis apparatus 50 executes S302, the vehicle is in an idle operation state with the vehicle stopped.

When the abnormality diagnosis device 50 is connected to a predetermined connector of the vehicle, the diagnosis operator instructs the abnormality diagnosis device 50 to perform abnormality diagnosis regarding the injection failure of the fuel injection valve 30.
In S <b> 302, the abnormality diagnosis device 50 executes abnormality diagnosis related to the injection failure of the fuel injection valve 30. The abnormality diagnosis of the fuel injection valve 30 will be described later.

  The abnormality diagnosis result of the fuel injection valve 30 is displayed on the monitor 54 in the format shown in FIG. At this time, the diagnosis result regarding the compression reduction in the cylinder 4 of the engine 2 is not displayed. The diagnosis operator can also display on the monitor 54 a detailed diagnosis result regarding the injection failure as shown in FIG.

  When the abnormality diagnosis of the fuel injection valve 30 in S302 is completed, the diagnostic operator stops the engine 2 in S304 and attaches a pressure sensor to the attachment hole of the glow plug 6 instead of the glow plug 6. Then, in a state where the engine 2 is stopped and fuel is not injected from the fuel injection valve 30, the diagnostic operator instructs the abnormality diagnosis device 50 to perform abnormality diagnosis regarding the compression reduction in the cylinder 4 of the engine 2.

In S <b> 306, the abnormality diagnosis device 50 executes abnormality diagnosis relating to the compression reduction in the cylinder 4. The engine 2 abnormality diagnosis will be described later.
The abnormality diagnosis result of the engine 2 is displayed on the monitor 54 in, for example, the format shown in FIGS. The diagnostic operator can also display on the monitor 54 a detailed diagnosis result regarding the compression reduction as shown in FIG.

  When the abnormality diagnosis of the engine 2 in S306 is completed, the diagnosis operator in S308 determines the fuel injection valve 30 and the engine 2 from the diagnosis results displayed on the monitor 54 in the format shown in FIGS. To determine whether the same abnormal level exists.

  As shown in FIG. 3B, when the same abnormality level (probable) exists in the # 2 cylinder fuel injection valve 30 and the engine 2 (S308: Yes), the diagnostic operator uses the abnormality diagnosis device 50. Based on the diagnosis result alone, it is determined that it cannot be specified whether the cause of the abnormality in the operating state is the fuel injection valve 30 or the engine 2. Therefore, the diagnosis operator instructs the abnormality diagnosis device 50 to stop driving the fuel injection valves 30 other than the # 2 cylinder to be diagnosed. In this state, the diagnosis operator manually performs abnormality diagnosis according to the diagnosis manual (S310).

  When the same abnormality level does not exist (S308: No), the diagnostic operator determines whether the fuel injection valve 30 has the cause of the abnormality in the operating state from the diagnosis result displayed on the monitor 54 (S312).

  Even when the fuel injection valve 30 and the engine 2 have the same high level, the diagnosis operator can determine whether the cause of the abnormality in the operating state is either the fuel injection valve 30 or the engine 2 by the diagnosis result of the abnormality diagnosis device 50 alone. It is determined that it cannot be specified, and abnormality diagnosis is performed manually according to the diagnosis manual.

When the same abnormality level does not exist (S308: No), the diagnosis operator similarly determines from the diagnosis result displayed on the monitor 54 whether the fuel injection valve 30 is the cause of the abnormality in the operating state (FIG. 3). C), when the abnormal level of the fuel injection valve 30 of the # 3 cylinder is probable and the abnormal level of the compression decrease of the # 3 cylinder is high probable, that is, the cause of the abnormal operating state is the fuel injection valve. When the engine 2 is not 30 (S312: No), the diagnostic operator performs a measure for the compression reduction of the # 3 cylinder (S314). For example, a diagnostic operator replaces a worn piston ring, intake valve or exhaust valve.

  As shown in FIG. 3D, when the abnormality level of the fuel injection valve 30 of the # 3 cylinder is high probeable and the diagnosis result of the compression reduction of the # 3 cylinder is no probe, that is, an abnormality in the operating state. When the cause is the fuel injection valve 30 (S312: Yes), even if the abnormality level of the fuel injection valve 30 of the # 2 cylinder is probable, the diagnostic operator performs the fuel injection of the # 3 cylinder having the highest abnormality level. The valve 30 is replaced (S316).

(Fuel injection valve 30 abnormal level classification routine)
The abnormal level classification routine of FIG. 5 is a subroutine executed in S302 of the main routine of FIG.

First, in S320 to S330, the abnormality diagnosis device 50 classifies the abnormality level of the fuel injection valve 30 of each cylinder 4 based on (A) the rotational fluctuation ΔNE.
In S320, the abnormality diagnosis device 50 acquires the rotational fluctuation ΔNE of each cylinder from the ECU 40. If ΔNE <N1 (S322: Yes), the abnormality diagnosis apparatus 50 classifies the diagnosis result of the corresponding cylinder into a no problem (S324).

If N1 ≦ ΔNE ≦ N2 (S326: Yes), the abnormality diagnosis device 50 classifies the abnormality level of the corresponding cylinder as probable (S328).
If N2 <ΔNE (S326: No), the abnormality diagnosis device 50 classifies the abnormality level of the corresponding cylinder as high probeable (S330).

Next, in S332 to S342, the abnormality diagnosis device 50 classifies the abnormality level of the fuel injection valve 30 of each cylinder 4 based on (B) the injection amount correction amount L.
In S332, the abnormality diagnosis apparatus 50 acquires the injection amount correction amount L from the ECU 40. If L <L1 (S334: Yes), the abnormality diagnosis device 50 classifies the diagnosis result of the corresponding cylinder into a no problem (S336).

If L1 ≦ L ≦ L2 (S338: Yes), the abnormality diagnosis device 50 classifies the abnormality level of the corresponding cylinder as probable (S340).
If L2 <L (S338: No), the abnormality diagnosis device 50 classifies the abnormality level of the corresponding cylinder as high probable (S342).

Next, in S344 to S354, the abnormality diagnosis device 50 classifies the abnormality level of the fuel injection valve 30 of each cylinder 4 based on (C) OBD misfire determination history.
In S344, the abnormality diagnosis apparatus 50 acquires the misfire determination history by the OBD from the ECU 40. If there is no misfire DTC (S346: Yes), this indicates that the corresponding cylinder has no misfire history in the past and present. Therefore, the abnormality diagnosis apparatus 50 classifies the diagnosis result of the corresponding cylinder into “no problem” (S348).

If there is a DTC that has misfired in the past (S350: Yes), the abnormality diagnosis device 50 classifies the abnormality level of the corresponding cylinder as probable (S352).
If there is no DTC that has misfired in the past but there is a DTC that is currently misfired (S350: No), the abnormality diagnosis device 50 classifies the abnormality level of the corresponding cylinder as high probable (S354).

  Next, in S356 to S364 in FIG. 6, the abnormality diagnosis device 50 determines the fuel injection valve based on the diagnosis results of (A) rotational fluctuation, (B) injection amount correction amount, and (C) OBD misfire determination history. Classify 30 abnormal states.

  If at least one of the abnormality diagnosis items (A) to (C) has a high level of an abnormal level (S356: Yes), the abnormality diagnosis device 50 classifies the abnormal level of the fuel injection valve 30 as a high level of probable ( S358).

  Although there is no high probeable in the abnormality diagnosis items (A) to (C), if there is even one probable abnormality level (S360: Yes), the abnormality diagnosis device 50 sets the abnormality level of the fuel injection valve 30 to probable. (S362).

  If all of the abnormality diagnosis items (A) to (C) are no problems (S360: No), the abnormality diagnosis device 50 classifies the diagnosis result of the fuel injection valve 30 into no problems (S364).

(Engine 2 abnormal level classification routine)
The abnormal level classification routine of FIG. 7 is a subroutine executed in S306 of the main routine of FIG.

In S370 to S384, the abnormality diagnosis device 50 classifies the abnormality level of each cylinder 4 based on the compression reduction in the cylinder 4.
In S370, the abnormality diagnosis device 50 acquires the cylinder internal pressure C of each cylinder 4 from the ECU 40.

If C1 ≦ C ≦ C2 (S372: Yes), the abnormality diagnosis device 50 classifies the diagnosis result of the corresponding cylinder 4 into a no problem (S374).
If C3 ≦ C ≦ C1 (S376: Yes), the abnormality diagnosis device 50 classifies the abnormal level of the corresponding cylinder as probable (S378).

If C ≦ C3 (S380: Yes), the abnormality diagnosis device 50 classifies the abnormality level of the corresponding cylinder as high probable (S382).
If C2 <C (S380: No), the abnormality diagnosis device 50 determines that the corresponding cylinder 4 is over-compressed (S384), and causes an abnormality in the monitor 54 in a format different from (C) in FIG. indicate.

  According to the present embodiment described above, data on the operating state of the engine 2 is acquired with the abnormality diagnosis device 50 connected to the ECU 40 of the vehicle, the injection failure of the fuel injection valve 30 of each cylinder 4, and the inside of the cylinder 4 The abnormal states of the compression reduction are classified into “proble” (mild abnormality) and “highly probable” and displayed on the monitor 54, respectively.

  As a result, from the relationship between the abnormal level of the injection failure of the fuel injection valve 30 in each cylinder and the abnormal level of the compression decrease in the cylinder 4, the cause of the abnormality in the operating state is the injection failure of the fuel injection valve or the in-cylinder It is possible to easily identify whether the compression is reduced.

[Other Embodiments]
In the above embodiment, in the main routine of FIG. 4, after abnormality diagnosis of the fuel injection valve 30 is executed in S302, the abnormality diagnosis by the abnormality diagnosis device 50 is interrupted, and in S304, instead of the glow plug 6 of each cylinder 4 of the injector. After attaching the pressure sensor to the attachment hole of the glow plug 6, an abnormality in the compression drop in the cylinder 4 was diagnosed in S306.

  On the other hand, regardless of whether the glow plug 6 is integrated or separated, if a pressure sensor is attached to each cylinder for detecting the cylinder internal pressure during normal operation, the main routine of FIG. The process of S304 may be omitted, and the abnormality diagnosis apparatus 50 may continuously execute the abnormality diagnosis of S302 and S306.

Further, the abnormality diagnosis of the compression decrease in the cylinder 4 in S306 may be executed prior to the abnormality diagnosis of the fuel injection of the fuel injection valve 30 in S302.
Moreover, in the said embodiment, the injection of the fuel injection valve 30 was stopped, the engine 2 was cranked with the starter motor, and the cylinder internal pressure of each cylinder 4 was acquired from the output signal of the pressure sensor. On the other hand, the cylinder pressure may be acquired from the output signal of the pressure sensor while the fuel is being injected from the fuel injection valve 30.

Moreover, in the said embodiment, although the abnormal level was classified into 2 levels of probable and high probeable, you may classify | categorize into 3 levels or more in detail.
Moreover, in the said embodiment, the function of an injection state acquisition means, an injection state classification means, a compression state acquisition means, a compression state classification means, and a display means is implement | achieved by the abnormality diagnosis apparatus 50 by which a function is specified by a control program. . On the other hand, at least some of the functions of the plurality of means may be realized by hardware whose functions are specified by the circuit configuration itself, for example.

  As described above, the present invention is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the gist thereof.

(A) is a block diagram showing a fuel supply system according to the present embodiment, (B) is an enlarged view of a cylinder. A display example showing the classification of the abnormality. A display example showing the classification of the abnormality. The flowchart which shows the main routine of abnormality diagnosis. The flowchart which shows the abnormality diagnosis routine of a fuel injection. The flowchart which shows the abnormality diagnosis routine of a fuel injection. The flowchart which shows the abnormality diagnosis routine of a compression fall.

Explanation of symbols

2: diesel engine (internal combustion engine), 4: cylinder, 6: glow plug, 10: fuel supply system, 16: high pressure pump (fuel supply pump), 20: common rail, 30: fuel injection valve, 40: ECU, 50: Abnormality diagnosis device (injection state acquisition means, injection state classification means, compression state acquisition means, compression state classification means, display means), 52: processing unit, 54: monitor (display means)

Claims (7)

In the internal combustion engine abnormality diagnosis device for diagnosing the cause of abnormality in the operating state of the internal combustion engine,
Injection state acquisition means for acquiring an injection state of a fuel injection valve for injecting fuel into each cylinder of the internal combustion engine;
Based on the injection state acquired by the injection state acquisition unit, an injection state classification unit that classifies the abnormal state of the injection failure of the fuel injection valve into a plurality of levels;
Compression state acquisition means for acquiring a compression state in the cylinder;
Based on the compression state acquired by the compression state acquisition means, compression state classification means for classifying the abnormal state of compression reduction in the cylinder into a plurality of levels;
An internal combustion engine abnormality diagnosis device comprising:   2. The internal combustion engine abnormality diagnosis device according to claim 1, further comprising display means for displaying the classification result of the injection state classification means and the classification result of the compression state classification means. The injection state acquisition means acquires the rotation fluctuation of each cylinder of the internal combustion engine, the injection amount correction amount of the fuel injection valve, and the misfire determination history as the injection state,
The injection state classification means classifies the abnormal state of the injection failure of the fuel injection valve into a plurality of light to heavy levels based on the rotation variation, the injection amount correction amount, and the misfire determination history.
The internal combustion engine abnormality diagnosis device according to claim 1 or 2. The compression state acquisition means acquires an in-cylinder pressure of each cylinder detected by a pressure sensor as the compression state,
The compression state classification means classifies the abnormality in compression reduction into a plurality of levels from light to heavy based on the cylinder internal pressure.
The internal combustion engine abnormality diagnosis device according to any one of claims 1 to 3, wherein   The compression state acquisition means stops the injection of the fuel injection valve after the injection state classification means classifies the abnormal state of the injection failure of the fuel injection valve into a plurality of levels, and rotates the internal combustion engine by driving a motor. 5. The internal combustion engine abnormality diagnosis device according to claim 1, wherein a compression state in the cylinder is acquired. An internal combustion engine abnormality diagnosis method using the internal combustion engine abnormality diagnosis device according to any one of claims 1 to 5,
When the compression state acquisition means acquires the compression state in the cylinder of the internal combustion engine, a pressure sensor that removes a glow plug installed in each cylinder of the internal combustion engine and detects the cylinder internal pressure of each cylinder as the compression state A method for diagnosing abnormality in an internal combustion engine, wherein the method is attached to an attachment hole of the glow plug. An internal combustion engine abnormality diagnosis method using the internal combustion engine abnormality diagnosis device according to any one of claims 1 to 5,
After comparing the classification result by the injection state classification means and the classification result by the compression state classification means, and when the abnormal state level is the same in the cylinder, after stopping the fuel injection valve drive by the abnormality diagnosis device An internal combustion engine abnormality diagnosis method comprising diagnosing the cause of abnormality of the operating state of the internal combustion engine by manual diagnosis.

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