Engine control device

Abstract

To suppress cloudiness of engine oil.SOLUTION: In an engine having an oil pump for delivering engine oil, an engine control device executes determination processing (S100) for determining whether or not the engine is in low output operation, and temperature raising processing (S120) for decreasing an oil delivery amount Vp of the oil pump when an oil temperature THO is lower than a threshold X (S110: YES) as compared with when the oil temperature THO is equal to or higher than the threshold X. The temperature raising processing in S120 is executed on the condition that it is determined in the determination processing that the engine is in low output operation (S100: YES).SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an engine control device. [Background technology]

[0002] An engine for a vehicle or the like is equipped with an oil pump that supplies engine oil in an oil pan to a sliding part. Patent Document 1 describes an engine control device that controls the oil pump to increase the amount of oil discharged when the temperature of the engine oil (hereinafter, referred to as the oil temperature) is below a predetermined temperature. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-255469 A Summary of the Invention [Problem to be solved by the invention]

[0004] When the oil temperature is low, engine oil may become cloudy due to condensed water produced by combustion, which may result in a decrease in the engine's lubricating ability. [Means for solving the problem]

[0005] The engine control device that solves the above problem is a device that controls an engine having an oil pump that discharges engine oil, and is configured to perform a judgment process that determines whether the engine is operating at low power or not, and a temperature rise process that reduces the amount of oil discharged from the oil pump when the temperature of the engine oil is below a threshold value compared to when the temperature of the engine oil is above the threshold value, and to perform the temperature rise process on the condition that it is determined in the judgment process that the engine is operating at low power. Effect of the Invention

[0006] The engine control device has the effect of suppressing the clouding of engine oil. [Brief description of the drawings]

[0007] [Figure 1] 1 is a diagram illustrating a schematic configuration of an embodiment of an engine control device; [Diagram 2] 4 is a flowchart of a process executed by the engine control device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of an engine control device will be described in detail with reference to FIGS. <Engine control unit configuration> First, the configuration of the engine control device of this embodiment will be described with reference to Fig. 1. Engine 10 to which this embodiment is applied is an on-vehicle hydrogen engine. Engine 10 is equipped with an electric oil pump 11. Oil pump 11 pumps engine oil from an oil pan 12 and discharges it toward sliding portion 13 of engine 10. After passing through sliding portion 13, the engine oil drips into oil pan 12.

[0009] An electronic control module (hereinafter, referred to as ECM) 20, which is a control device for the engine 10, includes a processing circuit 21 and a storage device 22. The storage device 22 stores programs and data used for controlling the engine 10. The processing circuit 21 reads out and executes the programs from the storage device 22. The ECM 20 receives detection signals from various sensors installed in various parts of the engine 10 and the vehicle in which the engine 10 is mounted. Sensors that output detection signals to the ECM 20 include a crank angle sensor 23, an air flow meter 24, a vehicle speed sensor 25, and an oil temperature sensor 26. The crank angle sensor 23 detects the rotation angle of the crankshaft, which is the output shaft of the engine 10. The air flow meter 24 detects the intake air amount GA of the engine 10. The vehicle speed sensor 25 detects the running speed (hereinafter, referred to as vehicle speed V) of the vehicle in which the engine 10 is mounted. The oil temperature sensor 26 detects the temperature of the engine oil in the oil pan 12 (hereinafter, referred to as oil temperature THO).

[0010] <Oil pump control> Next, the control of the oil pump 11 executed by the ECM 20 as part of the engine control will be described with reference to FIG. 2. FIG. 2 shows a flowchart of a process executed by the ECM 20 to set the oil discharge amount Vp of the oil pump 11. The ECM 20 repeatedly executes the process of FIG. 2 at each predetermined control cycle while the engine 10 is operating. In this process, the ECM 20 determines the oil discharge amount Vp. The oil discharge amount Vp represents the amount of engine oil discharged by the oil pump 11 per unit time. The ECM 20 adjusts the amount of power supplied to the oil pump 11 according to the oil discharge amount Vp determined in this process.

[0011] In the process of FIG. 2, the ECM 20 determines whether the logical product of conditions (A) and (B) is true or false. Condition (A) is a condition that the engine 10 is in low-power operation (S100: YES). For example, the ECM 20 determines that the engine 10 is in low-power operation when the vehicle speed V is equal to or lower than a threshold value Vx for a preset time or more. Condition (B) is a condition that the oil temperature THO is lower than a preset threshold value X (S110: YES). When the oil temperature THO exceeds a certain temperature, the condensed water in the engine oil evaporates and is separated from the engine oil. The threshold value X is set to a lower limit value of the oil temperature THO at which the condensed water in the engine oil evaporates. In the following description, the temperature set as the value of the threshold value X is referred to as the evaporation temperature of the condensed water.

[0012] When the logical product of the conditions (A) and (B) is false (S100: NO or S110: NO), the ECM 20 sets the standard value Vreg as the value of the oil discharge amount Vp (S130). On the other hand, when the logical product of the conditions (A) and (B) is true (S100: YES and S110: YES), the ECM 20 sets the reduction value Vlow as the value of the oil discharge amount Vp (S120). The reduction value Vlow is set to an amount less than the standard value Vreg. Specifically, the standard value Vreg is set as the oil discharge amount Vp that can supply the amount of engine oil required to operate the engine 10 efficiently to the sliding portion 13, taking into consideration friction loss and the driving load of the oil pump 11. The standard value Vreg may be a fixed value or may be a value that is variably set according to the operating conditions of the engine 10. The reduction value Vlow is set to an amount less than the standard value Vreg within a range in which the amount of engine oil required for lubricating the sliding portion 13, etc., can be supplied.

[0013] <Actions and Effects of the Embodiments> The operation and effects of this embodiment will be described. Oil pump 11 pumps out and discharges engine oil in oil pan 12. The engine oil discharged by oil pump 11 circulates through various parts of engine 10 and then returns to oil pan 12. The engine oil circulation path includes sliding parts 13 of engine 10, and the engine oil is used to lubricate sliding parts 13.

[0014] In the engine 10, moisture is generated by the combustion of hydrogen. When the engine 10 is cold, the moisture condenses and mixes with the engine oil in the oil pan 12. If the engine oil is stirred with the condensed water mixed in, it becomes cloudy and its lubricating ability decreases. Such clouding of the engine oil can occur when the oil temperature THO is lower than the evaporation temperature of the condensed water, which is set as the threshold value X.

[0015] The engine oil receives heat from the engine 10 while passing through the inside of the engine 10. Therefore, if the engine 10 generates a sufficiently large amount of heat, even if the temperature in the oil pan 12 is below the evaporation temperature of the condensed water, the temperature of the engine oil will rise to or above the evaporation temperature while passing through the inside of the engine 10. Therefore, the engine oil is likely to become cloudy when the logical product of the above conditions (A) and (B) is true, i.e., when the engine 10 is operating at low power and the oil temperature THO is below the threshold value X.

[0016] The ECM 20 performs a determination process in S100 of Fig. 2 to determine whether the engine 10 is operating at low power. In addition, the ECM 20 performs a temperature increase process in S120 of Fig. 2 to reduce the oil discharge amount Vp of the oil pump 11 when the oil temperature THO is less than the threshold value X (S110: YES) compared to when the oil temperature THO is equal to or higher than the threshold value X (S110: NO). The temperature increase process in S120 is performed on the condition that it is determined in the determination process in S100 that the engine 10 is operating at low power.

[0017] When the oil discharge rate Vp is reduced by the temperature increase process, the engine oil stays in the engine 10 for a longer period of time. This increases the amount of heat that the engine oil receives from the engine 10 while circulating inside the engine 10. Therefore, the temperature increase process is performed to promote the temperature increase of the engine oil. As a result, the temperature of the engine oil is more likely to rise above the evaporation temperature of the condensed water.

[0018] According to the engine control device of the present embodiment described above, the following effects can be achieved. (1) The ECM 20 performs a determination process to determine whether the engine 10 is in low-power operation, and a temperature increase process to reduce the oil discharge amount Vp of the oil pump 11 when the oil temperature THO is below the threshold value X, compared to when the oil temperature THO is equal to or higher than the threshold value X. Furthermore, the ECM 20 performs the temperature increase process on the condition that the engine 10 is determined to be in low-power operation in the determination process. When the temperature increase process is performed, the temperature increase of the engine oil is promoted, so that condensed water in the engine oil is easily evaporated. Therefore, the engine control device of this embodiment has the effect of suppressing the clouding of the engine oil.

[0019] (2) The ECM 20 determines that the engine 10 is in low-power operation when the vehicle speed V, which is the traveling speed of the vehicle equipped with the engine 10, remains equal to or lower than the threshold value Vx for a predetermined period of time or more. That is, the ECM 20 uses the vehicle speed V being equal to or lower than the threshold value Vx as a condition for determining that the engine 10 is in low-power operation in the determination process. For the steady running of the vehicle, the higher the vehicle speed V, the higher the engine output is required. Therefore, the vehicle speed V being equal to or lower than the threshold value Vx can be used as a condition for determining that the engine 10 is in low-power operation.

[0020] <Other embodiments> This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction.

[0021] In the above embodiment, it is determined that the engine 10 is in low output operation when the vehicle speed V remains equal to or lower than the threshold value Vx for a preset time or more. The determination process may be performed in a different manner while using the condition that the vehicle speed V is equal to or lower than the threshold value Vx as the determination condition. For example, it may be determined that the engine 10 is in low output operation when the average value of the vehicle speed V in a preset period of time is equal to or lower than the threshold value X.

[0022] In the above embodiment, the condition for determining that the engine 10 is in low-power operation in the determination process is that the vehicle speed V is equal to or less than the threshold value Vx. A similar determination can be made by using the engine speed NE or the engine torque instead of the vehicle speed V. That is, the condition for determining that the engine 10 is in low-power operation in the determination process can be that the engine speed NE is equal to or less than a threshold value, or that the engine torque is equal to or less than a threshold value. The engine speed NE can be calculated from the detection result of the crank angle sensor 23. The engine torque can be calculated based on the engine speed NE and the detection result of the intake air amount GA by the air flow meter 24.

[0023] The oil pump 11 may be a mechanical pump that is operated by the rotation of the engine 10 as long as it has a function for adjusting the amount of oil discharged. The engine oil may become cloudy due to the inclusion of water produced by combustion in engines other than hydrogen engines, such as gasoline engines and diesel engines. Therefore, the engine control device of the above embodiment may be applied to engines other than hydrogen engines. [Explanation of symbols]

[0024] 10 Engine 11 Oil pump 12 Oil pan 13 Sliding part 20 ECM 21 Processing circuit 22 Storage device 23 Crank angle sensor 24 Air flow meter 25 Vehicle speed sensor 26 Oil temperature sensor

Claims

1. A device for controlling an engine having an oil pump that discharges engine oil, a determination process for determining whether the engine is operating at a low power output; a temperature raising process for reducing an oil discharge amount of the oil pump when the temperature of the engine oil is less than a threshold value, compared to when the temperature of the engine oil is equal to or higher than the threshold value; and performing the temperature increase process on the condition that it is determined in the determination process that the engine is in a low output operation. Engine control device.

2. The engine control device according to claim 1 , wherein the determination process determines that the engine is operating at low power when the engine rotation speed is equal to or lower than a threshold value.

3. 2. The engine control device according to claim 1, wherein the determination process determines that the engine is operating at a low output when a traveling speed of a vehicle equipped with the engine is equal to or lower than a threshold value.

4. The engine control device according to claim 1 , wherein the determination process determines that the engine is operating at a low output when engine torque is equal to or less than a threshold value.

5. 2. The engine control device according to claim 1, wherein the engine is a hydrogen engine.

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