Engine control device, engine control method, and engine control program

Abstract

To provide an engine control device that can suppress a decrease in engine rotation speed regardless of the temperature of engine cooling water.SOLUTION: An engine control device comprises a processor that is configured to increase the amount of fuel injection based on a correction value predetermined according to the temperature of cooling water for cooling an engine when reducing the number of times of directly injecting fuel into an engine cylinder.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an engine control device, an engine control method, and an engine control program. [Background technology]

[0002] 2. Description of the Related Art Direct injection engines are known in the art, in which fuel is directly injected into the cylinders of the engine. In direct injection engines, the number of times that fuel is injected into the cylinders may be increased or decreased.

[0003] Fig. 5 is a timing chart showing the processing of a conventional engine control device. In the example of Fig. 5, at time T11, control is performed to reduce the number of injections from two to one. When the number of injections is reduced, the engine speed drops due to momentary misfire. After that, the A / F (air / fuel ratio) sensor measures the A / F, calculates a fuel F / B (Feedback) correction coefficient according to the measured A / F, and temporarily increases the total amount of fuel injected into the cylinder, suppressing the drop in engine speed.

[0004] Patent Document 1 also discloses a technology in which, when switching from a first injection method that performs a single injection to a second injection method that performs multiple injections, the injection state based on the first injection method is corrected to approach the engine torque after switching to the second injection method, and, when switching from the second injection method to the first injection method, the injection state in the injection with the larger injection amount among the multiple injections based on the second injection method is corrected to approach the torque after switching to the first injection method. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2000-018077 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the conventional technology shown in FIG. 5, the A / F ratio is detected on the exhaust side by an A / F sensor and feedback control is performed, so it is not possible to prevent the engine speed from decreasing due to a momentary misfire.

[0007] In addition, the lower the temperature of the engine coolant, the more likely it is that a momentary misfire will occur. Therefore, even if the technology of Patent Document 1 is used, it is not possible to prevent a drop in engine speed due to a momentary misfire when the coolant temperature is low.

[0008] The present invention has been made in consideration of the above, and aims to provide an engine control device, an engine control method, and an engine control program that can suppress a decrease in engine speed regardless of the temperature of the engine cooling water. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems, the engine control device of the present invention is equipped with a processor configured to increase the amount of fuel injected based on a predetermined correction value according to the temperature of the cooling water that cools the engine when reducing the number of times fuel is directly injected into the cylinders of the engine.

[0010] According to the above configuration, the amount of fuel injected is increased based on a predetermined correction value corresponding to the temperature of the cooling water that cools the engine, so that a decrease in engine speed can be suppressed regardless of the temperature of the engine cooling water.

[0011] In the engine control device, the correction value is set to a larger value as the water temperature is lower.

[0012] According to the above-described configuration, the lower the water temperature is and the more likely momentary misfire is to occur, the more fuel is supplied, so that a decrease in engine speed can be reliably suppressed.

[0013] In the engine control device, the fuel is a mixed fuel obtained by mixing gasoline and alcohol, and the correction value is set in accordance with the alcohol concentration contained in the fuel.

[0014] According to the above configuration, when the fuel is a mixed fuel of gasoline and alcohol, the amount of fuel injected is increased based on a correction value set according to the alcohol concentration, so that a decrease in engine speed can be suppressed regardless of the alcohol concentration.

[0015] In addition, in the engine control device, the correction value is set to a larger value as the alcohol concentration is higher.

[0016] According to the above-described configuration, the amount of fuel is increased as the alcohol concentration of the mixed fuel increases and the likelihood of momentary misfire increases, so that a decrease in the engine speed can be reliably suppressed.

[0017] In addition, in an engine control device according to one embodiment of the present invention, when reducing the number of times that the fuel is directly injected into the cylinder of the engine from two times to one time, the processor increases the amount of fuel injected based on the correction value.

[0018] According to the above configuration, when the number of times that fuel is directly injected into the cylinder of the engine is reduced from two to one, a decrease in the engine speed can be suppressed regardless of the temperature of the engine cooling water.

[0019] In addition, an engine control method according to one embodiment of the present invention includes increasing the amount of fuel injected into an engine cylinder based on a predetermined correction value according to a water temperature of the cooling water that cools the engine when reducing the number of times that fuel is directly injected into the cylinder of the engine.

[0020] According to the above method, the amount of fuel injected is increased based on a predetermined correction value corresponding to the temperature of the cooling water that cools the engine, so that a decrease in engine speed can be suppressed regardless of the temperature of the engine cooling water.

[0021] In addition, an engine control program according to one embodiment of the present invention causes a processor to increase the amount of fuel injected into an engine cylinder based on a predetermined correction value according to the temperature of the cooling water that cools the engine when reducing the number of times that fuel is directly injected into the cylinder of the engine.

[0022] According to the above program, the amount of fuel injected is increased based on a predetermined correction value corresponding to the temperature of the cooling water that cools the engine, so that a decrease in engine speed can be suppressed regardless of the temperature of the engine cooling water. Effect of the Invention

[0023] According to the present invention, it is possible to realize an engine control device, an engine control method, and an engine control program that are capable of suppressing a decrease in engine speed regardless of the temperature of the engine coolant. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 is a block diagram showing a configuration of an engine control device according to an embodiment. [Diagram 2] FIG. 2 is a timing chart showing the processing of the engine control device according to the embodiment. [Diagram 3] FIG. 3 is a diagram showing the fuel injection timing in multi-injection. [Figure 4] FIG. 4 is a diagram showing the fuel injection timing in single injection. [Diagram 5] FIG. 5 is a timing chart showing the processing of a conventional engine control device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, an embodiment of an engine control device, an engine control method, and an engine control program according to the present invention will be described with reference to the drawings. Note that the present invention is not limited to these embodiments. The present invention can be generally applied to engine control devices, engine control methods, and engine control programs.

[0026] In addition, in the drawings, the same or corresponding elements are appropriately labeled with the same reference numerals. It should be noted that the drawings are schematic, and the dimensional relationships and ratios of each element may differ from the actual situation. The drawings may also include parts with different dimensional relationships and ratios.

[0027] (Embodiment) [Configuration of engine control device] Fig. 1 is a block diagram showing a configuration of an engine control device according to an embodiment. As shown in Fig. 1, the engine control device 1 according to the present embodiment includes an acquisition unit 2, a calculation unit 3, a control unit 4, and a storage unit 5.

[0028] The engine control device 1 is, for example, an ECU (Electronic Control Unit) of a vehicle having an engine, and is configured to include a CPU (Central Processing Unit), a non-volatile memory such as a flash memory, and a volatile memory such as a DRAM (Dynamic Random Access Memory). The fuel that drives the engine may be gasoline, but it may also be a mixed fuel of gasoline and alcohol.

[0029] The acquisition unit 2 acquires the temperature of the coolant that cools the engine from a water temperature gauge provided in the engine. The acquisition unit 2 also acquires the alcohol concentration contained in the fuel from an alcohol concentration meter provided in the engine. The acquisition unit 2 also acquires various measurement values ​​used for engine control, such as the engine speed and the A / F (Air / Fuel ratio) measured from the exhaust side.

[0030] The calculation unit 3 calculates a fuel F / B (Feedback) correction coefficient from the A / F acquired by the acquisition unit 2. Furthermore, the calculation unit 3 calculates the total in-cylinder injection amount to be directly injected into the cylinder of the engine using the calculated fuel F / B correction coefficient. When reducing the number of times that fuel is directly injected into the cylinder of the engine (for example, from twice to once), the calculation unit 3 reads out a correction value that is predetermined according to the water temperature and alcohol concentration from the storage unit 5, and calculates the injection amount so as to increase the injection amount of fuel based on this correction value. Specifically, the calculation unit 3 calculates an injection amount correction coefficient, which is a magnification factor for increasing the total in-cylinder injection amount, from the correction value, and multiplies the total in-cylinder injection amount by this injection amount correction coefficient to calculate the actual injection amount to be actually injected into the cylinder of the engine.

[0031] The control unit 4 controls the injectors in accordance with the actual injection amount calculated by the calculation unit 3, and controls the fuel injection amount and injection timing, thereby controlling the driving state of the engine.

[0032] The storage unit 5 is configured with a storage device having a non-volatile storage medium such as a hard disk drive (HDD) or a solid state drive (SSD). The storage unit 5 stores a control program executed by the control unit 4. The control program may be provided in the form of an installable or executable file recorded on a computer-readable recording medium such as a CD-ROM, a flexible disk (FD), a CD-R, or a digital versatile disk (DVD). The control program may be stored on a computer connected to a network such as the Internet, and may be acquired by the acquisition unit 2 via the network. The storage unit 5 also stores various parameters used for engine control, such as correction values ​​determined in advance according to the water temperature and the alcohol concentration.

[0033] [How to set correction values] The correction value is stored in the storage unit 5 as an adaptation constant map that is preset according to, for example, the water temperature and the alcohol concentration. The correction value may be set to a larger value as the water temperature is lower. This is because the lower the water temperature, the more likely it is that momentary misfire will occur, and the fuel injection amount needs to be increased. The correction value may be set to a larger value as the alcohol concentration is higher. This is because the higher the alcohol concentration, the more likely it is that momentary misfire will occur, as alcohol is less volatile than gasoline, and the higher the alcohol concentration, the more likely it is that momentary misfire will occur, and the fuel injection amount needs to be increased.

[0034] [Engine control device processing] Next, the operation of the engine control device 1 will be described. Fig. 2 is a timing chart showing the processing of the engine control device according to the embodiment. The horizontal axis of Fig. 2 represents time. First, at time T1, the control unit 4 switches the fuel injected into the cylinder of the engine from a two-injection (multiple injection) mode M2 ​​to a one-injection (single injection) mode M1.

[0035] Figure 3 is a diagram showing the fuel injection timing in multi-injection. The angles in Figure 3 indicate how far in advance of the compression point. With direct injection DI2-1, 0.5 of the total injection amount is taken as 1 is injected 300° before the compression point. With direct injection DI2-2, 0.5 of the total injection amount is taken as 1 is injected 200° before the compression point.

[0036] Figure 4 is a diagram showing the fuel injection timing in single injection. The angle in Figure 4 indicates how far in advance of the compression point, as in Figure 3. In the case of direct injection DI1, the total injection amount is set to 1, and 1 (full amount) is injected 200° before the compression point.

[0037] 2, the calculation unit 3 reads out a correction value based on the water temperature and the alcohol concentration from the storage unit 5, and calculates an injection amount correction coefficient to increase the fuel injection amount. Then, the control unit 4 performs control to inject an actual injection amount, which is calculated by multiplying the total in-cylinder injection amount by the injection amount correction coefficient, into the cylinder of the engine at time T2.

[0038] Then, the control unit 4 maintains this injection amount correction coefficient until a predetermined number of injections have been performed. Fig. 2 shows an engine with four cylinders, and the timing at which injectors #1 to #4 of each cylinder are energized and fuel is injected. In the example of Fig. 2, the control unit 4 maintains the initial injection amount correction coefficient until fuel has been directly injected four times into each cylinder (times T2 to T3), and then multiplies the injection amount correction coefficient by a predetermined damping coefficient to gradually decrease the injection amount correction coefficient.

[0039] As described above, when reducing the number of times that fuel is directly injected into the engine cylinder from two times to one time, the engine control device 1 of this embodiment increases the amount of fuel injected based on a predetermined correction value according to the temperature of the cooling water that cools the engine, so that a decrease in engine speed can be suppressed regardless of the temperature of the engine cooling water.

[0040] In addition, according to the engine control device 1, when the number of times that fuel is directly injected into the engine cylinder is reduced, the amount of fuel injected is temporarily increased, so that the amount of fuel injected can be increased appropriately and efficiently only at times when momentary misfires are likely to occur.

[0041] In addition, by setting the correction value to a larger value as the water temperature decreases, the amount of fuel is increased the lower the water temperature is and the more likely it is that a momentary misfire will occur, so that a decrease in engine speed can be reliably suppressed.

[0042] In addition, when the fuel is a mixed fuel of gasoline and alcohol, the amount of fuel injected can be increased based on a correction value set according to the alcohol concentration, thereby suppressing a decrease in engine speed regardless of the alcohol concentration.

[0043] In addition, by setting the correction value to a larger value as the alcohol concentration increases, the amount of fuel is increased the higher the alcohol concentration of the mixed fuel and the more likely it is that a momentary misfire will occur, thereby reliably suppressing a decrease in engine speed.

[0044] In the above-described embodiment, when the number of times that fuel is directly injected into the cylinder of the engine is reduced from two to one, the amount of fuel injection is increased based on a correction value that is predetermined according to the temperature of the cooling water that cools the engine, but this is not limiting. When the number of times that fuel is directly injected into the cylinder of the engine is reduced (for example, from three to two, from three to one, from four to three, etc.), the amount of fuel injection may be increased based on a correction value that is predetermined according to the temperature of the cooling water that cools the engine.

[0045] Further advantages and modifications may readily occur to those skilled in the art. Thus, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Thus, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and equivalents thereof. [Explanation of symbols]

[0046] 1 Engine control device 2 Acquisition part 3. Calculation section 4. Control section 5 Storage section

Claims

1. An engine control device comprising a processor configured to increase the amount of fuel injected based on a predetermined correction value according to the temperature of cooling water that cools the engine when reducing the number of times fuel is directly injected into a cylinder of the engine.

2. The engine control device according to claim 1 , wherein the correction value is set to a larger value as the water temperature decreases.

3. The fuel is a mixed fuel of gasoline and alcohol, The engine control device according to claim 1 , wherein the correction value is set in accordance with an alcohol concentration contained in the fuel.

4. The engine control device according to claim 3 , wherein the correction value is set to a larger value as the alcohol concentration increases.

5. 2 . The engine control device according to claim 1 , wherein the processor increases the amount of fuel injection based on the correction value when reducing the number of times that the fuel is directly injected into a cylinder of the engine from two to one.

6. An engine control method comprising: when reducing the number of times that fuel is directly injected into a cylinder of the engine, increasing an amount of the fuel injected based on a predetermined correction value according to a water temperature of cooling water that cools the engine.

7. The processor: An engine control program that, when reducing the number of times that fuel is directly injected into a cylinder of an engine, increases the amount of fuel injected based on a predetermined correction value according to a water temperature of cooling water that cools the engine.

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