ENGINE SYSTEM

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No. 2024-176420 filed on October 8, 2024. The disclosure of the above-identified application, including the specification, drawings, and claims, is incorporated by reference herein in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to an engine system.

2. Description of Related Art

An oil tank that stores oil for lubricating an engine communicates with the engine through an oil pipe and communicates with a portion downstream of a throttle valve in an intake pipe through a blow-by gas pipe (for example, see Japanese Unexamined Patent Application Publication No. 2016-196864 (JP 2016-196864 A)).

SUMMARY

In a case where an operation of the engine is continued when some abnormalities occur in such an oil pipe or blow-by gas pipe, blow-by gas may be continuously released into an atmosphere.

Therefore, an object of the present disclosure is to provide an engine system capable of notifying a user of an abnormality in an oil pipe or a blow-by gas pipe.

The above object can be achieved by an engine system including an engine, a throttle valve provided in an intake pipe of the engine, an oil tank that stores oil for lubricating the engine, an oil pipe through which the oil flows from the oil tank to the engine and blow-by gas flows from the engine to the oil tank, a first blow-by gas pipe through which the blow-by gas flows from the oil tank downstream of the throttle valve in the intake pipe, a pressure sensor that detects a pressure in the oil tank, and a notification control device that executes notification processing of notifying a user that an abnormality has occurred in at least one of the oil pipe and the first blow-by gas pipe in a case where a deviation amount of the pressure in the oil tank from a normal pressure is equal to or greater than a threshold, the pressure in the oil tank being detected by the pressure sensor.

The engine system may include a compressor of a supercharger provided in the intake pipe and located upstream of the throttle valve, and a second blow-by gas pipe through which the blow-by gas flows from the oil tank upstream of the compressor in the intake pipe in a case where an operating area of the engine is a supercharging area, in which the notification control device may execute the notification processing of notifying the user that an abnormality has occurred in at least one of the oil pipe, the first blow-by gas pipe, and the second blow-by gas pipe in a case where the deviation amount is equal to or greater than the threshold.

According to the present disclosure, it is possible to provide the engine system capable of notifying the user of the abnormality in the oil pipe or the blow-by gas pipe.

BRIEF DESCRIPTION OF THE DRAWINGS

Features, advantages, and technical and industrial significance of exemplary embodiments of the disclosure will be described below with reference to the accompanying drawings, in which like signs denote like elements, and wherein:

FIG. 1 is a schematic configuration diagram of an engine system of a first example;

FIG. 2 is a flowchart illustrating the abnormality notification control;

FIG. 3 is a timing chart showing a transition of the tank internal pressure in a case where the abnormality has occurred; and

FIG. 4 is a schematic configuration diagram of an engine system of a second example.

DETAILED DESCRIPTION OF EMBODIMENTS

First Example

FIG. 1 is a schematic configuration diagram of an engine system of a first example. The engine system is mounted on, for example, a vehicle. The engine system includes an engine 1, an oil tank 10, an electronic control unit (ECU) 20, and a display 30. The engine 1 is a series engine, but is not limited thereto. In addition, the engine 1 is a gasoline engine, but may be a diesel engine.

An intake pipe 4 is connected to the engine 1. The intake pipe 4 is provided with a throttle valve 6 and the intake manifold 2 from upstream to downstream. The intake manifold 2 is connected to an intake port of the engine 1. An exhaust pipe is connected to the engine 1.

A fresh air introduction pipe 16 that communicates upstream of the throttle valve 6 of the intake pipe 4 with the engine 1 is provided. When the pressure in the engine 1 is equal to or lower than the atmospheric pressure, the fresh air is introduced into the engine 1 through the fresh air introduction pipe 16, and the negative pressure in the engine 1 is suppressed.

The ECU 20 is configured around a computer including a central processing unit (CPU), a volatile or non-volatile memory such as a random access memory (RAM) or a read only memory (ROM). The ECU 20 is an example of a notification control device.

The ignition switch 21, a pressure sensor 22, an intake pressure sensor 23, and a display 30 are connected to the ECU 20. The ignition switch 21 detects an on/off state of the ignition. The pressure sensor 22 detects a tank internal pressure that is a pressure in a space in the oil tank 10 filled with the gas. The intake pressure sensor 23 detects an intake pressure in the intake manifold 2. The ECU 20 adjusts the opening degree of the throttle valve 6 according to the operation state of the engine 1. The display 30 is provided, for example, on an instrument panel of a vehicle.

The oil tank 10 is a dry sump type tank that stores oil for lubrication of the engine 1. The oil tank 10 is connected to the engine 1 via an oil pipe 10a. The oil used in the engine 1 flows into the oil tank 10 through the oil pipe 10a by driving the scavenging pump P1. In addition, the blow-by gas generated in the engine 1 also flows into the oil tank 10 through the oil pipe 10a. The scavenging pump P1 is a mechanical pump that is driven to be synchronized with the rotation of the crankshaft 1a of the engine 1. The oil stored in the oil tank 10 is sent to each lubrication part of the engine 1 by a feed pump P2 provided in the engine 1.

The oil separated from the blow-by gas is stored in a lower portion of the oil tank 10. The blow-by gas stays in the upper portion of the oil tank 10. A blow-by gas pipe 15 that communicates the upper portion of the oil tank 10 with the intake manifold 2 is provided. The blow-by gas pipe 15 is an example of a first blow-by gas pipe. The blow-by gas pipe 15 is provided with a check valve 14. The check valve 14 allows the gas to flow from the oil tank 10 to the intake manifold 2, but restricts the gas from flowing from the intake manifold 2 to the oil tank 10.

While the engine 1 is being operated, the pressure in the oil tank 10 is higher than the pressure in the intake manifold 2. As a result, the check valve 14 is opened, and the blow-by gas in the oil tank 10 is supplied to the combustion of the engine 1 through the blow-by gas pipe 15.

As described above, the oil used in the engine 1 is recovered by the scavenging pump P1, the oil pipe 10a, and the oil tank 10. Further, the blow-by gas generated in the engine 1 is returned to the engine 1 by the scavenging pump P1, the oil pipe 10a, the oil tank 10, and the blow-by gas pipe 15. Therefore, the mechanisms are mechanisms for realizing the recovery of the oil and the return of the blow-by gas. The ECU 20 can estimate the flow rate of the blow-by gas flowing through the blow-by gas pipe 15 by a difference between the pressures detected by the pressure sensor 22 and the intake pressure sensor 23.

Abnormality Notification Control

FIG. 2 is a flowchart illustrating the abnormality notification control. The flowchart is repeatedly executed while the ignition is on. The ECU 20 determines whether a deviation amount from a normal pressure of the tank internal pressure detected by the pressure sensor 22 is equal to or greater than a threshold (S1). The deviation amount is a value obtained by subtracting the tank internal pressure detected by the pressure sensor 22 from the normal pressure. The normal pressure is the minimum value of the tank internal pressure that can be obtained during the driving of the engine 1 in a state where there is no hole or missing part in the oil pipe 10a or the blow-by gas pipe 15, and is a pressure higher than the atmospheric pressure. The threshold is a pressure of a decrease from a normal pressure when a hole is provided in the oil pipe 10a or the blow-by gas pipe 15, or the oil pipe 10a or the blow-by gas pipe 15 is disconnected. When No in S1, the present control ends.

When the determination in S1 is Yes, it is considered that the tank internal pressure is decreased to near the atmospheric pressure due to the occurrence of the hole in at least one of the oil pipe 10a and the blow-by gas pipe 15. Alternatively, it is considered that the tank internal pressure has decreased to near the atmospheric pressure due to the fact that at least one of the oil pipe 10a and the blow-by gas pipe 15 has been disconnected. In this case, the blow-by gas in the oil tank 10 is released to the atmosphere. Therefore, the ECU 20 executes abnormality notification processing of notifying the user that the abnormality has occurred in at least one of the oil pipe 10a and the blow-by gas pipe 15 (S2). The ECU 20 may display the fact on the display 30 to notify the user, for example, or may notify the user through a malfunction indicator light (MIL) or a speaker.

FIG. 3 is a timing chart showing a transition of the tank internal pressure in a case where the abnormality has occurred. For example, when a hole is opened in the blow-by gas pipe 15, the tank internal pressure gradually decreases with respect to the normal pressure (time t1). When the deviation amount from the normal pressure of the tank internal pressure gradually increases and the deviation amount is equal to or greater than the threshold, the abnormal notification processing described above is executed (time t2). With such notification, the user can be prompted to stop the engine 1 and perform the inspection. By stopping the engine 1, the release of the blow-by gas to the atmosphere can be suppressed.

Second Example

FIG. 4 is a schematic configuration diagram of an engine system of a second example. In the engine system of the second example, the engine 1 has a supercharger. Therefore, the compressor 5 of the supercharger is provided upstream of the throttle valve 6 in the intake pipe 4. Further, a blow-by gas pipe 13 that communicates an upper portion of the oil tank 10 with upstream of the compressor 5 of the intake pipe 4 is provided. The blow-by gas pipe 13 is an example of a second blow-by gas pipe. The blow-by gas pipe 13 is provided with a check valve 12. The check valve 12 allows the gas to flow from the oil tank 10 upstream of the compressor 5 of the intake pipe 4, but restricts the gas from flowing from upstream of the compressor 5 of the intake pipe 4 to the oil tank 10. In addition, the fresh air introduction pipe 16a communicates upstream of the compressor 5 of the intake pipe 4 with the engine 1.

During natural aspiration, the pressure in the oil tank 10 is higher than the pressure in the intake manifold 2. As a result, the check valve 14 is opened, and the blow-by gas in the oil tank 10 is supplied to the combustion of the engine 1 through the blow-by gas pipe 15. When the supercharging is performed, the pressure in the oil tank 10 is higher than the pressure upstream of the compressor 5. As a result, the check valve 12 is opened, and the blow-by gas in the oil tank 10 is supplied to the combustion of the engine 1 through the blow-by gas pipe 13.

When the tank internal pressure detected by the pressure sensor 22 is lower than a normal range, the ECU 20a executes abnormality notification processing. The abnormality notification processing is processing of notifying the user that the abnormality has occurred in at least one of the oil pipe 10a, the blow-by gas pipe 15, and the blow-by gas pipe 13.

Although the embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to such specific embodiments, and can be variously modified and changed within the scope of the gist of the present disclosure described in the claims.