JP2022035601A - Glow plug diagnostic device - Google Patents

Abstract

To simply diagnose abnormality of a glow plug after start of an internal combustion engine.SOLUTION: A glow plug diagnostic device 10 comprises: an energization control unit 142 that energizes a glow plug when starting an internal combustion engine, to preheat a combustion chamber; an angular velocity detection unit 143 that detects the magnitude of an angular velocity of the internal combustion engine after energizing the glow plug; and an abnormality presumption unit 144 that presumes that the glow plug is abnormal when the magnitude of the angular velocity detected by the angular velocity detection unit 143 is smaller than a predetermined value.SELECTED DRAWING: Figure 2

Description

The present invention relates to a glow plug diagnostic device.

Some internal combustion engines are equipped with glow plugs that preheat the combustion chamber at start-up. For example, preheating is performed by energizing a glow plug to generate heat. By the way, since an abnormality such as a failure may occur in the glow plug, in Patent Document 1 below, the abnormality of the glow plug is determined based on the resistance value at the time of energization after the operation of the internal combustion engine is stopped.

Japanese Unexamined Patent Publication No. 2009-36092

Immediately after starting the internal combustion engine, a method of detecting an abnormality of the glow plug based on the current waveform of the glow plug when the glow plug is energized, which is measured by the glow plug control module (GPCM), has been proposed. However, since GPCM is an expensive device, there is a demand for a method of detecting an abnormality in a glow plug with a simple configuration.

Therefore, the present invention has been made in view of these points, and an object of the present invention is to easily diagnose an abnormality of a glow plug after starting an internal combustion engine.

In one aspect of the present invention, an energization control unit that energizes the glow plug when the internal combustion engine is started to preheat the combustion chamber, and an angular speed that detects the magnitude of the angular velocity of the internal combustion engine after the glow plug is energized. A glow plug diagnostic apparatus including a detection unit and an abnormality estimation unit that estimates that the glow plug is abnormal when the magnitude of the angular velocity detected by the angular velocity detection unit is smaller than a predetermined value. offer.

Further, the energization control unit energizes the glow plugs provided in each of the plurality of cylinders of the internal combustion engine, and the abnormality estimation unit has the magnitude of the angular velocity detected by the angular velocity detection unit from the predetermined value. It may be presumed that the glow plug provided in the small cylinder is abnormal.

Further, the glow plug diagnostic device stores the predetermined value stored in the storage unit based on the storage unit for storing the predetermined value and the fluctuation of the angular speed of the internal combustion engine when the glow plug is normal. It may be further provided with an update unit for updating.

Further, the glow plug diagnostic device may further include a notification control unit that notifies that the glow plug is abnormal when it is estimated that the glow plug is abnormal.

According to the present invention, there is an effect that an abnormality of the glow plug can be easily diagnosed after the internal combustion engine is started.

It is a schematic diagram for demonstrating the vehicle 1 equipped with the glow plug diagnostic apparatus. It is a block diagram for demonstrating an example of the structure of the glow plug diagnostic apparatus 10. It is a flowchart for demonstrating the diagnostic process of the glow plugs 5a to 5d.

<Configuration of glow plug diagnostic device>
The glow plug diagnostic device is a device for diagnosing the state of the glow plug provided in the internal combustion engine. The glow plug diagnostic device is installed in a vehicle having an internal combustion engine, for example.

FIG. 1 is a schematic diagram for explaining a vehicle 1 equipped with a glow plug diagnostic device. As shown in FIG. 1, the vehicle 1 has an internal combustion engine 2, glow plugs 5a to 5d, and a glow plug diagnostic device 10. In FIG. 1, for convenience of explanation, the illustration of other configurations of the vehicle 1 is omitted.

The internal combustion engine 2 is, for example, a diesel engine. The internal combustion engine 2 has a plurality of cylinders (here, four cylinders 4a to 4d). The cylinders 4a to 4d are provided with pistons that reciprocate in the cylinder. Combustion / explosion occurs in the combustion chambers in the cylinders 4a to 4d, and the piston reciprocates. The reciprocating motion of the piston is converted into the rotational motion of the crankshaft of the internal combustion engine 2.

The glow plugs 5a to 5d are heat sources that assist in starting the internal combustion engine 2. The glow plugs 5a to 5d are provided in cylinders 4a to 4d (specifically, a combustion chamber) and have a heat generating portion. The glow plugs 5a to 5d generate heat when the internal combustion engine 2 is started to preheat the combustion chambers of the cylinders 4a to 4d.

The glow plug diagnostic device 10 diagnoses the state of the glow plugs 5a to 5d. Specifically, the glow plug diagnostic device 10 diagnoses whether or not an abnormality such as a failure has occurred in the glow plugs 5a to 5d. The details of the glow plug diagnostic device 10 of the present embodiment will be described later, but immediately after the start of the internal combustion engine 2, whether or not an abnormality has occurred in the glow plugs 5a to 5d based on the magnitude of the angular velocity of the internal combustion engine 2. To judge. Thereby, with a simple configuration, the state of the glow plugs 5a to 5d immediately after the start of the internal combustion engine 2 can be appropriately diagnosed.

(Detailed configuration of glow plug diagnostic device)
The detailed configuration of the glow plug diagnostic apparatus 10 will be described with reference to FIG.

FIG. 2 is a block diagram for explaining an example of the configuration of the glow plug diagnostic apparatus 10. The glow plug diagnostic device 10 has a storage unit 12 and a control unit 14.

The storage unit 12 includes, for example, a ROM (Read Only Memory) and a RAM (Random Access Memory). The storage unit 12 stores programs and various data for execution by the control unit 14.

The control unit 14 is, for example, a CPU (Central Processing Unit). The control unit 14 performs glow plug diagnostic processing by executing the program stored in the storage unit 12. In the present embodiment, the control unit 14 functions as an energization control unit 142, an angular velocity detection unit 143, an abnormality estimation unit 144, an update unit 145, and a notification control unit 146.

The energization control unit 142 controls energization to the glow plugs 5a to 5d provided in each of the cylinders 4a to 4d. For example, the energization control unit 142 energizes the glow plugs 5a to 5d when the internal combustion engine 2 is started to preheat the combustion chambers of the cylinders 4a to 4d. If the glow plugs 5a to 5d are in a normal state, the temperature in the combustion chamber becomes high.

The angular velocity detection unit 143 detects the magnitude of the angular velocity of the internal combustion engine 2 after the glow plugs 5a to 5d are energized. For example, the angular velocity detection unit 143 detects the magnitude of the angular velocity of the crankshaft of the internal combustion engine 2. The angular velocity detection unit 143 outputs information regarding the magnitude of the detected angular velocity to the abnormality estimation unit 144.

Normally, when the glow plugs 5a to 5d are in a normal state, combustion / explosion in the combustion chamber is promoted, and the angular speed of the internal combustion engine 2 (specifically, the crankshaft of the internal combustion engine 2) increases. On the other hand, when an abnormality such as a failure occurs in the glow plugs 5a to 5d, it becomes difficult for an explosion in the combustion chamber to occur, and the angular velocity of the internal combustion engine 2 becomes small.

The abnormality estimation unit 144 estimates the presence or absence of an abnormality in the glow plugs 5a to 5d based on the magnitude of the angular velocity of the internal combustion engine 2 detected by the angular velocity detection unit 143. For example, the abnormality estimation unit 144 estimates that the glow plugs 5a to 5d are abnormal when the magnitude of the angular velocity detected by the angular velocity detection unit 143 is smaller than a predetermined value. On the other hand, the abnormality estimation unit 144 estimates that the glow plugs 5a to 5d are operating normally when the magnitude of the angular velocity detected by the angular velocity detection unit 143 is equal to or greater than a predetermined value.

The above predetermined value is stored in the storage unit 12. The magnitude of the predetermined value is set based on the fluctuation of the angular velocity of the internal combustion engine 2 when the glow plugs 5a to 5d are operating normally. Therefore, by comparing the magnitude of the angular velocity detected by the angular velocity detection unit 143 with the predetermined value stored in the storage unit 12, it is possible to easily estimate whether or not the glow plugs 5a to 5d are abnormal. That is, the abnormality of the glow plugs 5a to 5d can be estimated without using an expensive device such as GPCM.

The abnormality estimation unit 144 can identify an abnormal glow plug among the four glow plugs 5a to 5d based on the detection timing of the angular velocity detection unit 143. In the internal combustion engine 2 having four cylinders 4a to 4d, the timing of the explosion in the combustion chamber of each cylinder is deviated. Therefore, if the detection timing is known, it is possible to identify the cylinder in which the magnitude of the angular velocity is smaller than the predetermined value. As a result, the abnormality estimation unit 144 estimates that among the four glow plugs 5a to 5d, the glow plug provided in the cylinder in which the magnitude of the angular velocity detected by the angular velocity detection unit 143 is smaller than the predetermined value is abnormal. do. Thereby, an abnormal glow plug can be appropriately identified among the four glow plugs 5a to 5d.

The update unit 145 updates a predetermined value stored in the storage unit 12. For example, the update unit 145 updates a predetermined value stored in the storage unit 12 based on the fluctuation of the angular velocity of the internal combustion engine 2 when the glow plugs 5a to 5d are normal. Specifically, the updating unit 145 updates the predetermined value to the learning value learned from the magnitude of the angular velocity when the glow plugs 5a to 5d are operating normally. As a result, it is possible to update to a predetermined value that reflects the actual operating conditions of the glow plugs 5a to 5d, so that the abnormality estimation of the glow plugs 5a to 5d can be performed with high accuracy.

The notification control unit 146 causes the notification unit 8 to notify that the abnormality is abnormal. Specifically, the notification control unit 146 is abnormal when the abnormality estimation unit 144 estimates that the glow plugs 5a to 5d (specifically, any of the glow plugs 5a to 5d) are abnormal. Notify the notification to that effect to the notification unit 8. The notification unit 8 outputs voice to notify the notification, or displays characters on the display unit to notify the notification. As a result, the driver can easily recognize that the glow plugs 5a to 5d are abnormal immediately after the internal combustion engine 2 is started, so that it becomes easy to take countermeasures.

<Glow plug diagnostic processing>
The diagnostic processing of the glow plugs 5a to 5d performed by the glow plug diagnostic apparatus 10 will be described with reference to FIG.

FIG. 3 is a flowchart for explaining the diagnostic processing of the glow plugs 5a to 5d. This process starts from the point where the internal combustion engine 2 starts.

First, the energization control unit 142 of the glow plug diagnostic device 10 energizes the glow plugs 5a to 5d (step S102). If the glow plugs 5a to 5d are in a normal state, they generate heat to preheat the combustion chamber.

Next, the angular velocity detection unit 143 detects the magnitude of the angular velocity of the internal combustion engine 2 after the glow plugs 5a to 5d are energized (step S104). For example, the angular velocity detection unit 143 detects the magnitude of the angular velocity of the crankshaft of the internal combustion engine 2.

Next, the abnormality estimation unit 144 determines whether or not the magnitude of the angular velocity detected by the angular velocity detection unit 143 is smaller than the predetermined value stored in the storage unit 12 (step S106). If the magnitude of the angular velocity is equal to or greater than a predetermined value in step S106 (No), the abnormality estimation unit 144 estimates that the glow plugs 5a to 5d are not abnormal.

On the other hand, when it is determined in step S106 that the magnitude of the angular velocity is smaller than the predetermined value (Yes), the abnormality estimation unit 144 estimates that the glow plugs 5a to 5d are abnormal (step S108). Specifically, the abnormality estimation unit 144 estimates that the glow plug in the cylinder at the timing when the magnitude of the angular velocity becomes smaller than the predetermined value is abnormal.

<Effect in this embodiment>
The glow plug diagnostic apparatus 10 of the above-described embodiment detects the magnitude of the angular velocity of the internal combustion engine 2 after the glow plugs 5a to 5d are energized. Then, when the magnitude of the detected angular velocity is smaller than the predetermined value, the glow plug diagnostic apparatus 10 estimates that the glow plug is abnormal.
As a result, by comparing the magnitude of the angular velocity of the internal combustion engine 2 detected by the angular velocity detection unit 143 with the predetermined value, it is possible to easily estimate whether or not the glow plugs 5a to 5d are abnormal immediately after the operation of the internal combustion engine 2. can. That is, it can be easily estimated whether or not the glow plugs 5a to 5d are abnormal without using an expensive device such as GPCM.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes can be made within the scope of the gist. be. For example, all or part of the device can be functionally or physically distributed / integrated in any unit. Also included in the embodiments of the present invention are new embodiments resulting from any combination of the plurality of embodiments. The effect of the new embodiment produced by the combination has the effect of the original embodiment together.

2 Internal combustion engine 4a-4d Cylinder 5a-5d Glow plug 10 Glow plug diagnostic device 142 Energization control unit 143 Angular velocity detection unit 144 Abnormality estimation unit 145 Update unit 146 Notification control unit

Claims (4)

An energization control unit that energizes the glow plug when starting the internal combustion engine to preheat the combustion chamber,
An angular velocity detection unit that detects the magnitude of the angular velocity of the internal combustion engine after the glow plug is energized.
When the magnitude of the angular velocity detected by the angular velocity detection unit is smaller than a predetermined value, the abnormality estimation unit that estimates that the glow plug is abnormal and the abnormality estimation unit.
A glow plug diagnostic device. The energization control unit energizes the glow plugs provided in each of the plurality of cylinders of the internal combustion engine.
The abnormality estimation unit estimates that the glow plug provided in the cylinder whose angular velocity is smaller than the predetermined value detected by the angular velocity detection unit is abnormal.
The glow plug diagnostic apparatus according to claim 1. A storage unit that stores the predetermined value and
A renewal unit for updating the predetermined value stored in the storage unit based on the fluctuation of the angular velocity of the internal combustion engine when the glow plug is normal is further provided.
The glow plug diagnostic apparatus according to claim 1 or 2. Further, a notification control unit for notifying that the glow plug is abnormal when it is presumed that the glow plug is abnormal is provided.
The glow plug diagnostic apparatus according to any one of claims 1 to 3.

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