Engine abnormality diagnostic device

Abstract

To provide an engine abnormality diagnostic device which excels in versatility.SOLUTION: An engine abnormality diagnostic device comprises: an acquisition section which acquires the number of required fuel injection times during one combustion cycle of an engine; a counting section which counts the actual number of fuel injection times during one combustion cycle of the engine; a determination section which determines whether the number of required fuel injection times is plural; and a diagnostic section which diagnoses that the engine undergoes abnormality when the number of required fuel injection times is plural and the actual number of fuel injection times is lower than the plural or when the number of required fuel injection times is one and the actual number of fuel injection times is zero.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an engine abnormality diagnosis device.

Background Art

[0002] There is a technique for diagnosing that an abnormality has occurred in an engine when the actual number of fuel injections during one combustion cycle is less than the required number of fuel injections for an engine assuming that the required number of fuel injections during one combustion cycle is plural (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As described above, there are engines assuming that the required number of fuel injections during one combustion cycle is plural, and there are also engines assuming that it is one. The above technique does not target engines assuming that the required number of fuel injections is one, and cannot diagnose engine abnormalities. Thus, the above technique has low versatility.

[0005] Therefore, an object of the present invention is to provide an engine abnormality diagnosis device with excellent versatility.

Means for Solving the Problems

[0006] The above object can be achieved by an engine abnormality diagnosis device including: an acquisition unit that acquires the required injection times of fuel during one combustion cycle of the engine; a counting unit that counts the actual injection times of fuel during one combustion cycle of the engine; a determination unit that determines whether the required injection times are plural; and a diagnosis unit that diagnoses that an abnormality has occurred in the engine when the actual injection times are less than the plural times when the required injection times are plural, or when the actual injection times are zero when the required injection times are one time.

[0007] The acquisition unit may acquire the required injection times before the engine has completed warm-up, and the counting unit may count the actual injection times before the engine has completed warm-up.

Advantages of the Invention

[0008] An engine abnormality diagnosis device with excellent versatility can be provided.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0010] [Schematic Configuration of Engine] FIG. 1 is a schematic configuration diagram of the engine 1. The engine 1 is mounted on, for example, a vehicle, but is not limited thereto, and may be mounted on a ship or the like other than a vehicle. The engine 1 includes an engine body 10, an intake passage 20, and an exhaust passage 30. The engine body 10 is a multi-cylinder engine having a plurality of cylinders, and a combustion chamber 11, a piston 12, a spark plug 16, etc. are provided in each cylinder. Further, a connecting rod 13 and a crankshaft 14 are arranged inside the engine body 10. The piston 12 is connected to the crankshaft 14 by the connecting rod 13. A rotation speed sensor 15 is provided on the engine body 10, and a fuel injection valve 17 is provided for each cylinder. The rotation speed sensor 15 detects the rotation speed of the engine body 10 by detecting the rotation speed of the crankshaft 14. Further, a water temperature sensor for detecting the temperature of the cooling water for cooling the engine body 10 is provided on the engine body 10.

[0011] The fuel injection valve 17 is an in-cylinder injection valve that directly injects fuel into the combustion chamber 11. Incidentally, instead of the fuel injection valve 17, a port injection valve that injects fuel toward the intake port of the engine body 10 may be provided. Further, a port injection valve may be provided in addition to the fuel injection valve 17. The spark plug 16 ignites the air-fuel mixture in the combustion chamber 11. The intake passage 20 and the exhaust passage 30 are connected to the intake port and the exhaust port of the engine body 10, respectively. The intake valve 18a and the exhaust valve 18b open and close the intake port and the exhaust port of the engine body 10, respectively.

[0012] In the intake passage 20, an air cleaner 21, an air flow meter 22, and a throttle valve 23 are provided in order from the upstream side to the downstream side. The air cleaner 21 removes dust and the like from the air flowing in from the outside. The air flow meter 22 acquires the intake air amount. The throttle valve 23 adjusts the intake air amount.

[0013] When the intake valve 18a opens, air is introduced from the intake passage 20 into the combustion chamber 11. The air-fuel mixture injected from the fuel injection valve 17 is compressed by the piston 12 and ignited by the spark plug 16. Ignition of the air-fuel mixture causes the piston 12 to reciprocate up and down within the combustion chamber 11, and the crankshaft 14 rotates. The exhaust gas after combustion is discharged from the exhaust passage 30.

[0014] A catalyst 32 is provided in the exhaust passage 30. The catalyst 32 is a three-way catalyst having an oxygen storage capacity, and purifies NOx and HC in the exhaust gas by catalytic action and oxygen storage capacity.

[0015] The ECU (Electric Control Unit) 100 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and a storage device such as a flash memory, and performs various controls by executing programs stored in the ROM and the storage device. The ECU 100 controls the spark plug 16, the fuel injection valve 17, and the throttle valve 23 based on the operation amounts of the accelerator pedal and the brake pedal operated by the driver, the rotational speed of the engine body 10, the load, etc. The ECU 100 acquires the rotational speed detected by the rotational speed sensor 15, the intake air amount detected by the air flow meter 22, and the temperature of the cooling water detected by the water temperature sensor 19.

[0016] The ECU 100 is an example of an engine abnormality diagnostic device. Also, the ECU 100 functionally realizes an acquisition unit, a count unit, a determination unit, and a diagnostic unit, which will be described later, by the above-described CPU, RAM, ROM, and storage device. The ECU 100 executes abnormality diagnostic control as described below.

[0017] [Abnormality Diagnostic Control] FIG. 2 is a flowchart illustrating the abnormal diagnosis control. First, the ECU 100 determines whether or not the warm-up of the engine body 10 is completed (step S1). Before the warm-up is completed means the period from when the engine 1 starts until the temperature of the cooling water becomes equal to or higher than the warm-up completion temperature while the temperature of the cooling water is lower than the warm-up completion temperature. If the answer in step S1 is No, this control ends. If the answer in step S1 is Yes, the ECU 100 acquires the required injection number N (N is an integer of 1 or more) (step S2). Step S2 is an example of the process executed by the acquisition unit. Next, the ECU 100 counts the actual injection number of fuel during one combustion cycle (step S3). Specifically, within the period from the previous ignition timing to the next ignition timing, the ECU 100 counts the number of energizations to the fuel injection valve 17 to count the actual injection number. Step S3 is an example of the process executed by the counting unit.

[0018] Next, the ECU 100 determines whether or not the required injection number N is plural (step S4). Step S4 is an example of the process executed by the determination unit. If the answer in step S4 is Yes, the ECU 100 determines whether or not the actual injection number is less than the required injection number N (step S5). If the answer in step S5 is No, this control ends. If the answer in step S4 is No, the required injection number N is regarded as 1, and the ECU 100 determines whether or not the actual injection number is 0 (step S6). If the answer in step S6 is No, this control ends. If the answer in step S5 or S6 is Yes, the ECU 100 diagnoses that an abnormality has occurred in the engine 1 (step S7). Incidentally, when it is diagnosed that an abnormality has occurred in the engine 1, the ECU 100 can notify the driver of the abnormality of the engine 1, for example, by turning on the MIL (Malfunction Indicator Light). Step S7 is an example of the process executed by the diagnosis unit.

[0019] As described above, when the required injection count N of engine 1 before warm-up completion is plural, such an abnormality of engine 1 can be diagnosed by the above-described abnormality diagnosis control. Also, when the required injection count N of engine 1 before warm-up completion is 1, such an abnormality of engine 1 can be diagnosed by the above-described abnormality diagnosis control. Thus, the abnormality of the engine can be diagnosed by the above-described abnormality diagnosis control for both an engine in which the required injection count N is plural and an engine in which the required injection count N is 1. Therefore, the ECU 100 that executes such an abnormality diagnosis control is excellent in versatility. Also, in the above-described abnormality diagnosis control, the abnormality diagnosis is executed before warm-up completion. Thereby, the abnormality of engine 1 can be diagnosed at an early stage.

[0020] In addition, in an engine in which the required injection count N before warm-up completion is set to plural, the injection fuel amount per time is decreased to promote fuel vaporization, and the intake air in the cylinder collects the fuel around the ignition plug 16 to suppress the adhesion of the fuel to the inner wall surface of the cylinder. For example, in an engine in which the required injection count N before warm-up completion is 3, the promotion of fuel vaporization and the suppression of the adhesion of the fuel to the inner wall surface of the cylinder are effectively performed.

[0021] Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

Description of Reference Numerals

[0022] 1 Engine 100 ECU (Engine Abnormality Diagnosis Device, Acquisition Unit, Count Unit, Determination Unit, Diagnosis Unit)

Claims

1. An acquisition unit that acquires the required number of fuel injection times during one combustion cycle in the engine; A counting unit that counts the actual number of fuel injection times during one combustion cycle in the engine; A determination unit that determines whether the required number of injection times is plural; A diagnostic unit that diagnoses that an abnormality has occurred in the engine when the actual number of injection times is less than the plural times when the required number of injection times is plural, or when the actual number of injection times is zero when the required number of injection times is one. An engine abnormality diagnosis device comprising:

2. The acquisition unit acquires the required number of injection times before the engine has completed warm-up, The counting unit counts the actual number of injection times before the engine has completed warm-up. The engine abnormality diagnosis device according to claim 1.

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