Control device for internal combustion engines

Abstract

The present invention provides a control device for an internal combustion engine that can prevent the crankcase from being scavenged unnecessarily. [Solution] The internal combustion engine 10 is capable of performing a scavenging process to clean the inside of the crankcase 11. The control device 1 of the internal combustion engine 10 includes a processing circuit 1A that determines whether or not it is a low-temperature environment when the ignition off operation is performed, and performs the scavenging process if it is determined to be a low-temperature environment, and does not perform the scavenging process if it is determined not to be a low-temperature environment.

Description

Technical Field

[0001] The present disclosure relates to a control device for an internal combustion engine.

Background Art

[0002] Conventionally, an internal combustion engine capable of performing scavenging processing for scavenging blow-by gas and the like in a crankcase is known (see, for example, Patent Document 1). By performing the scavenging processing, generation of condensed water in the crankcase and freezing of the condensed water can be suppressed.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of Invention

Problem to be Solved by the Invention

[0004] In the control device for controlling the internal combustion engine as described above, there is a problem that the scavenging processing is executed even in an environment where generation of condensed water in the crankcase and freezing of the condensed water are unlikely to occur.

Means for Solving the Problem

[0005] A control device for an internal combustion engine that solves the above problem is a control device for an internal combustion engine capable of performing scavenging processing for scavenging the inside of a crankcase, and the control device determines whether or not the environment is a low-temperature environment when an ignition-off operation is performed, executes the scavenging processing when it is determined that the environment is the low-temperature environment, and does not execute the scavenging processing when it is determined that the environment is not the low-temperature environment.

Effects of the Invention

[0006] According to the control device for an internal combustion engine of the present disclosure, execution of the crankcase scavenging processing in an unnecessary situation can be suppressed.

Brief Description of Drawings

[0007] [Figure 1] Figure 1 is a schematic diagram showing the configuration of an internal combustion engine. [Figure 2] Figure 2 is a flowchart showing the steps of the process performed by the control unit of an internal combustion engine. [Modes for carrying out the invention]

[0008] As shown in Figure 1, the control device 1 controls the vehicle's internal combustion engine 10. The internal combustion engine 10 is the vehicle's power source and uses fuel such as hydrogen or gasoline. The internal combustion engine 10 includes a crankcase 11 located at the bottom of a cylinder block (not shown).

[0009] <Configuration of internal combustion engine 10> The internal combustion engine 10 is connected to an intake passage 12 and an exhaust passage 13. The intake passage 12 is a passage for introducing air into the combustion chamber of the internal combustion engine 10. The exhaust passage 13 is a passage for discharging exhaust gas from the combustion chamber of the internal combustion engine 10.

[0010] The intake passage 12 includes an intake manifold 14, a throttle valve 15, and an air cleaner 16. The air cleaner 16, throttle valve 15, and intake manifold 14 are arranged in that order from the upstream side of the intake passage 12. The air cleaner 16 filters the air taken into the intake passage 12. The throttle valve 15 is a valve that adjusts the amount of intake air for the internal combustion engine 10. The opening of the throttle valve 15 is changed, for example, by a motor. The intake manifold 14 is connected to the intake port in the cylinder head of the internal combustion engine 10.

[0011] <Crankcase 11 scavenging system> The internal combustion engine 10 has a scavenging system for scavenging, for example, blow-by gases in the crankcase 11. Blow-by gases are gases that leak from the combustion chamber into the crankcase 11 during the compression stroke or combustion stroke of the internal combustion engine 10. Blow-by gases include, for example, combustion gases, unburned fuel mixtures, and lubricating oil for the internal combustion engine 10.

[0012] The scavenging system of the crankcase 11 includes, for example, a first passage 21 and a second passage 22. The first passage 21 is a passage that connects the crankcase 11 and the intake manifold 14. The first passage 21 includes a PCV (Positive Crankcase Ventilation) valve 21a. The PCV valve 21a is a one-way valve. The PCV valve 21a restricts the flow of gas from the intake manifold 14 to the crankcase 11, while allowing the flow of gas from the crankcase 11 to the intake manifold 14. The PCV valve 21a opens when the pressure inside the intake manifold 14 becomes lower than the pressure inside the crankcase 11. This allows gas from inside the crankcase 11 to flow into the intake manifold 14.

[0013] The second passage 22 is a passage that connects the intake passage 12 and the crankcase 11. The second passage 22 branches off, for example, from the portion of the intake passage 12 between the air cleaner 16 and the throttle valve 15.

[0014] <Scavenging treatment of crankcase 11> Next, we will describe the scavenging process of the crankcase 11 that the internal combustion engine 10 can perform. For example, when the internal combustion engine 10 is idling, the intake air is restricted by the throttle valve 15 to regulate the load on the internal combustion engine 10. As a result, the pressure in the intake manifold 14 downstream of the throttle valve 15 in the intake passage 12 becomes lower than the pressure in the crankcase 11. This causes the PCV valve 21a to open in the first passage 21.

[0015] When the PCV valve 21a opens, air flows from the intake passage 12 into the crankcase 11 via the second passage 22, and blow-by gas in the crankcase 11 is drawn into the intake manifold 14 via the first passage 21. In this manner, the blow-by gas in the crankcase 11 is scavenged. The blow-by gas drawn into the intake manifold 14 is sent together with intake air to the combustion chamber of the internal combustion engine 10 to be combusted.

[0016] <Configuration of Control Device 1> The control device 1 for the internal combustion engine 10 includes a processing circuit 1A. The processing circuit 1A acquires detection results from various sensors mounted on the vehicle. The sensors include a temperature sensor 31. The temperature sensor 31 detects, for example, the outside air temperature. The outside air temperature is the air temperature outside the vehicle.

[0017] When an ignition-off operation is performed, the processing circuit 1A determines whether or not the environment is a low-temperature environment. The processing circuit 1A executes scavenging processing for the crankcase 11 when determining that the environment is a low-temperature environment, and does not execute the scavenging processing for the crankcase 11 when determining that the environment is not a low-temperature environment.

[0018] <Operation and Effect of Processing Circuit 1A> The specific operation and effect of the above processing circuit 1A will be described with reference to Figure 2. In a state where the internal combustion engine 10 is operated in an idling state, for example, when an ignition-off operation is performed by the driver and a stop command for the internal combustion engine 10 is input to the control device 1, the processing circuit 1A determines whether or not the environment is a low-temperature environment (step S1). Here, the processing circuit 1A determines whether or not the environment is a low-temperature environment based on, for example, the outside air temperature detected by the temperature sensor 31. The low-temperature environment is, for example, an environment where the outside air temperature is 0° or lower.

[0019] When the processing circuit 1A determines in step S1 that the environment is a low-temperature environment (step S1: YES), the processing circuit 1A proceeds to step S2, and continues the operation of the internal combustion engine 10 in an idling state. Thereby, the scavenging process for the crankcase 11 described above is executed.

[0020] Thereafter, the processing circuit 1A proceeds to step S3 for stopping the idling state (that is, stopping the internal combustion engine 10). After step S2 in which the operation of the internal combustion engine 10 in the idling state is continued, the processing circuit 1A proceeds to step S3 based on a predetermined condition. The predetermined condition is, for example, that the elapsed time from the input of the stop command by the ignition-off operation reaches a preset set time.

[0021] When the processing circuit 1A determines in step S1 that the environment is not a low-temperature environment (step S1: NO), the processing circuit 1A proceeds to the step S3. Thereby, the internal combustion engine 10 is stopped. <Effects of the Present Embodiment> The processing circuit 1A of the control device 1 determines whether or not the environment is a low-temperature environment when an ignition-off operation is performed. Then, when determining that the environment is a low-temperature environment, the processing circuit 1A executes the scavenging process for the crankcase 11 (specifically, executes continuation of the idling state). As a result, in a low-temperature environment, even if the ignition-off operation is performed, the internal combustion engine 10 is not stopped and the idling state is continued, and the gas in the crankcase 11 is scavenged. For this reason, it is possible to suppress the generation of condensed water in the crankcase 11 and the freezing of the condensed water.

[0022] On the other hand, if the processing circuit 1A determines that the environment is not low temperature when the ignition is turned off, it will not perform the scavenging process in the crankcase 11. In other words, it will stop the internal combustion engine 10. As a result, in non-low temperature environments where condensation and freezing of that condensation are unlikely to occur in the crankcase 11, the internal combustion engine 10 will stop quickly after the ignition is turned off. Therefore, it is possible to suppress the execution of the crankcase 11 scavenging process when it is not necessary. As a result, for example, it is possible to contribute to improved fuel efficiency and suppress any discomfort to the driver. Alternatively, the internal combustion engine 10 may be equipped with an electric pump or the like capable of scavenging the crankcase 11, and the system may be configured to perform the scavenging process in the crankcase 11 using this electric pump. [Explanation of Symbols]

[0023] 1...Control device 1A...Processing circuit 10...Internal combustion engine 11...Crankcase

Claims

[Claim 1] A control device for an internal combustion engine capable of performing a scavenging process to scavenge the inside of the crankcase, The system includes a processing circuit that, when the ignition is turned off, determines whether or not the environment is low temperature, executes the scavenging process if it is determined to be a low temperature environment, and refrains from executing the scavenging process if it is determined not to be a low temperature environment. Control device for internal combustion engines.

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