Control device for internal combustion engine

Abstract

To provide a control device for an internal combustion engine capable of stably controlling rotational frequency.SOLUTION: A control device is for an internal combustion engine including a first cylinder group and a second cylinder group. The control device for the internal combustion engine includes: a first control section for controlling rotational frequency of the first cylinder group; and a second control section for controlling rotational frequency of the second cylinder group. The first control section determines first rotational frequency that is a target value of the rotational frequency of the first cylinder group, and the second control section determines second rotational frequency that is a target value of the rotational frequency of the second cylinder group. The first control section sets larger one of the first rotational frequency and the second rotational frequency as the target value of the rotational frequency of the first cylinder group, and the second control section sets the larger one of the first rotational frequency and the second rotational frequency as the target value of the rotational frequency of the second cylinder group.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] There are known internal combustion engines having multiple cylinder groups, such as horizontal engines and V-type engines. The multiple cylinders are arranged in left and right banks. An independent control device is provided for each bank, and each control device controls the throttle valve corresponding to the bank (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-228878 Summary of the Invention [Problem to be solved by the invention]

[0004] When control is performed independently for each bank, the target rotation speed for one bank may differ from the target rotation speed for the other bank. When feedback control of the rotation speed of an internal combustion engine is performed, the two target rotation speeds are different, and therefore the feedback amount for each bank also differs. This causes the feedback amount to diverge, making the rotation speed unstable. Therefore, an object of the present invention is to provide a control device for an internal combustion engine that can stably control the rotation speed. [Means for solving the problem]

[0005] The above object can be achieved by a control device for an internal combustion engine having a first cylinder group and a second cylinder group, the control device including a first control unit that controls a rotation speed of the first cylinder group, and a second control unit that controls a rotation speed of the second cylinder group, wherein the first control unit sets a first rotation speed that is a target value of the rotation speed of the first cylinder group, the second control unit sets a second rotation speed that is a target value of the rotation speed of the second cylinder group, the first control unit sets the larger of the first rotation speed and the second rotation speed as the target value of the rotation speed of the first cylinder group, and the second control unit sets the larger of the first rotation speed and the second rotation speed as the target value of the rotation speed of the second cylinder group. Effect of the Invention

[0006] It is possible to provide a control device for an internal combustion engine that is capable of stably controlling the rotation speed. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram illustrating an engine system according to an embodiment. [Diagram 2] FIG. 2 is a flowchart illustrating the processing executed by the ECU. [Diagram 3] FIG. 3 is a flowchart illustrating a process executed by the ECU. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an internal combustion engine control device according to an embodiment will be described with reference to the drawings. Fig. 1 is a schematic diagram illustrating an engine system 100 according to an embodiment. As shown in Fig. 1, the engine system 100 has an internal combustion engine 10, an ECU (Electronic Control Unit) 40 (first control unit), and an ECU 42 (second control unit).

[0009] The internal combustion engine 10 is, for example, a horizontally opposed engine or a V-type engine. The internal combustion engine 10 has, for example, four cylinders 11 and four cylinders 12. The four cylinders 11 are aligned in a row to form a left bank 10L (first cylinder group). The four cylinders 12 are aligned in a row to form a right bank 10R (second cylinder group).

[0010] Each cylinder is provided with an ignition plug (not shown). The internal combustion engine 10 is provided with a fuel injection valve (not shown) that supplies fuel to the four cylinders 11 in the left bank 10L, and a fuel injection valve (not shown) that supplies fuel to the four cylinders 12 in the right bank 10R. The fuel injection valve may be of a port injection type or of an in-cylinder injection type.

[0011] Intake passages 14L and 14R and exhaust passages 20L and 20R are connected to the internal combustion engine 10. The intake passages 14L and the exhaust passages 20L are connected to each of the four cylinders 11 in the left bank 10L. The intake passages 14R and the exhaust passages 20R are connected to each of the four cylinders 12 in the right bank 10R.

[0012] An air flow meter 16L and a throttle valve 18L are provided in the intake passage 14L, in that order from the upstream side. The air flow meter 16L measures the flow rate of air in the intake passage 14L. The throttle valve 18L controls the flow rate of air in the intake passage 14L. When the opening of the throttle valve 18L increases, the air flow rate increases. When the opening of the throttle valve 18L decreases, the air flow rate decreases.

[0013] An air flow meter 16R and a throttle valve 18R are provided in the intake passage 14R, in that order from the upstream side. The air flow meter 16R measures the flow rate of air in the intake passage 14R. The throttle valve 18R controls the flow rate of air in the intake passage 14R. When the opening of the throttle valve 18R increases, the air flow rate increases. When the opening of the throttle valve 18R decreases, the air flow rate decreases. An air cleaner (not shown) for purifying the air is provided in the intake passages 14L and 14R.

[0014] An exhaust purification section 22L is provided in the exhaust passage 20L. An exhaust purification section 22R is provided in the exhaust passage 20R. The exhaust purification sections 22L and 22R include a filter and a catalyst, and purify the exhaust. The filter collects particulate matter (PM) in the exhaust. The catalyst is, for example, a three-way catalyst, and removes harmful substances in the exhaust, such as carbon monoxide (CO), unburned fuel (HC), and nitrogen oxides (NOx), to purify the exhaust.

[0015] Air is introduced into the cylinders of the internal combustion engine 10 through intake passages 14L and 14R. For example, fuel such as gasoline is supplied to the multiple cylinders of the internal combustion engine 10 from a fuel injection valve (not shown). A mixture of fuel and air is generated in the multiple cylinders. The mixture is ignited by a spark plug (not shown) or the like, causing it to burn. Exhaust gas generated by the combustion is discharged from exhaust passages 20L and 20R. The combustion of the mixture rotates a crankshaft (not shown), generating driving force.

[0016] The alternator 26 is a generator that generates electricity using driving force transmitted from the internal combustion engine 10 via pulleys and belts (not shown), and charges the battery 28. The power of the battery 28 is used to operate auxiliary machinery (not shown).

[0017] The crank angle sensor 30 detects the rotation angle of the crankshaft of the internal combustion engine 10. The first water temperature sensor 32 detects the temperature of the cooling water in the left bank 10L of the internal combustion engine 10. The second water temperature sensor 34 detects the temperature of the cooling water in the right bank 10R of the internal combustion engine 10.

[0018] Each of the ECUs 40 and 42 is a control device including a calculation device such as a CPU (Central Processing Unit), and storage devices such as a flash memory, a ROM (Read Only Memory), and a RAM (Random Access Memory).

[0019] The ECU 40 acquires the state of charge (SOC) of the battery 28. The ECU 40 acquires the water temperature in the left bank 10L from the first water temperature sensor 32. The ECU 40 acquires the rotation angle of the crankshaft detected by the crank angle sensor 30, and calculates the rotation speed of the internal combustion engine 10. The ECU 40 determines a target rotation speed for the left bank 10L. The ECU 40 controls the rotation speed of the internal combustion engine 10 by controlling the opening degree of the throttle valve 18L.

[0020] The ECU 42 acquires the SOC of the battery 28. The ECU 42 acquires the water temperature in the right bank 10R from the second water temperature sensor 34. The ECU 42 acquires the rotation angle of the crankshaft detected by the crank angle sensor 30, and acquires the rotation speed of the internal combustion engine 10. The ECU 42 determines a target rotation speed for the right bank 10R. The ECU 42 controls the opening degree of the throttle valve 18R to control the rotation speed.

[0021] For example, during idling, the rotation speed of the internal combustion engine 10 is controlled based on the water temperature, the SOC of the battery 28, etc. When the water temperature and SOC are low, the rotation speed of the internal combustion engine 10 is increased compared to when the water temperature and SOC are high. By increasing the rotation speed, the internal combustion engine 10 is warmed up. The temperature of the exhaust purification units 22L and 22R can be increased, and the purification efficiency can be improved. By increasing the rotation speed of the internal combustion engine 10, the amount of power generated by the alternator 26 is increased, and the battery 28 is charged.

[0022] The ECU 40 determines a target rotation speed R1 (first rotation speed) that is a target value of the rotation speed for the left bank 10L based on the water temperature obtained from the first water temperature sensor 32, the SOC, etc. The ECU 42 determines a target rotation speed R2 (second rotation speed) for the right bank 10R based on the water temperature obtained from the second water temperature sensor 34, the SOC, etc.

[0023] The timing when the ECU 40 calculates the target rotation speed R1 may differ from the timing when the ECU 42 calculates the target rotation speed R2. The water temperature when the target rotation speed R1 is calculated differs from the water temperature when the target rotation speed R2 is calculated. The SOC when the target rotation speed R1 is calculated differs from the SOC when the target rotation speed R2 is calculated. As a result, the target rotation speed R1 has a different value from the target rotation speed R2.

[0024] The ECU 40 feedback-controls the rotation speed of the internal combustion engine 10 based on the target rotation speed R1, and the ECU 42 feedback-controls the rotation speed of the internal combustion engine 10 based on the target rotation speed R2. Since the two target rotation speeds are different from each other, the feedback amount of the ECU 40 and the feedback amount of the ECU 42 differ. The feedback amount diverges, and the rotation speed of the internal combustion engine 10 becomes unstable.

[0025] Assume that the target rotation speed R1 is 100 revolutions higher and the target rotation speed R2 is 100 revolutions lower than the rotation speed R of the internal combustion engine 10 at a certain time. The target rotation speed ECU 40 increases the opening of the throttle valve 18L according to the difference of 100 revolutions, thereby increasing the rotation speed R toward the target rotation speed R1. The difference between the increased rotation speed R and the target rotation speed R2 becomes larger than 100 revolutions. The ECU 42 decreases the opening of the throttle valve 18R according to the difference between the increased rotation speed R and the target rotation speed R2, thereby decreasing the rotation speed R. The ECU 40 performs feedback control based on the decreased rotation speed R and the target rotation speed R1, thereby increasing the rotation speed. As described above, the target rotation speed R1 determined by the ECU 40 differs from the target rotation speed R2 determined by the ECU 42, which causes the rotation speed R of the internal combustion engine 10 to become unstable.

[0026] In this embodiment, the rotation speed of the internal combustion engine 10 is stably controlled by setting a single target rotation speed.

[0027] Fig. 2 is a flowchart illustrating the processing executed by the ECU 40. Fig. 3 is a flowchart illustrating the processing executed by the ECU 42. The processing in Fig. 2 and the processing in Fig. 3 are performed in parallel.

[0028] As shown in FIG. 2, the ECU 40 sets a target rotation speed R1 for the left bank 10L (step S10). The ECU 40 transmits the target rotation speed R1 to the ECU 42 (step S12). The ECU 40 acquires a target rotation speed R2 for the right bank 10R transmitted from the ECU 42 (step S14). The ECU 40 determines whether the target rotation speed R1 is greater than the target rotation speed R2 (step S16). If the determination is affirmative (Yes), the ECU 40 sets the target rotation speed for the left bank 10L to R1 (step S18). If the determination is negative (No), the ECU 40 sets the target rotation speed for the left bank 10L to R2 (step S19). After step S18 or S19, the process ends. That is, the ECU 40 sets the larger of R1 and R2 as the target rotation speed for the left bank 10L.

[0029] As shown in FIG. 3, the ECU 42 sets a target rotation speed R2 for the right bank 10R (step S20). The ECU 42 transmits the target rotation speed R2 to the ECU 40 (step S22). The ECU 42 acquires the target rotation speed R1 for the left bank 10L transmitted from the ECU 40 (step S24). The ECU 42 determines whether the target rotation speed R2 is greater than the target rotation speed R1 (step S26). If the determination is affirmative, the ECU 42 sets the target rotation speed for the right bank 10R to R2 (step S28). If the determination is negative, the ECU 42 sets the target rotation speed for the right bank 10R to R1 (step S29). After step S28 or S29, the process ends. That is, the ECU 42 sets the larger of R1 and R2 as the target rotation speed for the right bank 10R.

[0030] According to this embodiment, the ECU 40 sets the target rotation speed R1 for the left bank 10L, and the ECU 42 sets the target rotation speed R2 for the right bank 10R. The ECU 40 sets the larger of R1 and R2 as the target rotation speed for the left bank 10L (FIG. 2). The ECU 42 sets the larger of R1 and R2 as the target rotation speed for the right bank 10R (FIG. 3). As a result, the target rotation speed for the left bank 10L and the target rotation speed for the right bank 10R become the same value. Based on the target rotation speed, the ECU 40 controls the opening of the throttle valve 18L to control the rotation speed of the internal combustion engine 10. The ECU 42 controls the opening of the throttle valve 18R to control the rotation speed of the internal combustion engine 10. The rotation speed is stabilized by the ECU 40 and the ECU 42 controlling the rotation speed of the internal combustion engine 10 based on the same target rotation speed.

[0031] According to the embodiment, by setting the larger of R1 and R2 as the target rotation speed, the rotation speed of the internal combustion engine 10 becomes higher than when the smaller of R1 and R2 is set as the target rotation speed. The increase in the rotation speed makes it possible to warm up the internal combustion engine 10, warm up the exhaust purification units 22L and 22R, and charge the battery 28 by increasing the amount of power generated by the alternator 26.

[0032] The ECUs 40 and 42 may control the ignition timing of a spark plug (not shown) to control the rotation speed of the internal combustion engine 10. The number of cylinders of the internal combustion engine 10 is not limited to eight, and may be eight or less, or eight or more. For example, the internal combustion engine 10 may have two cylinders. One cylinder corresponds to the left bank 10L, and the other cylinder corresponds to the right bank 10R.

[0033] Although a preferred embodiment of the present invention has been described in detail above, the present invention is not limited to such a specific embodiment, and various modifications and variations are possible within the scope of the gist of the present invention described in the claims. [Explanation of symbols]

[0034] 10 Internal combustion engine 10L Left bank 10R Right Bank 11, 12 cylinders 14L, 14R intake passages 16L, 16R Airflow Meter 18L, 18R throttle valve 20L, 20R exhaust passage 22L, 22R Exhaust purification unit 26 Alternator 28 Battery 30 Crank angle sensor 32 No. 1 water temperature sensor 34 Second water temperature sensor 40, 42 ECU 100 Engine System

Claims

[Claim 1] A control device for an internal combustion engine having a first cylinder group and a second cylinder group, a first control unit that controls the rotation speed of the first cylinder group; a second control unit that controls the rotation speed of the second cylinder group, the first control unit determines a first rotation speed which is a target value of the rotation speed of the first cylinder group; the second control unit determines a second rotation speed which is a target value of the rotation speed of the second cylinder group; the first control unit sets the larger of the first rotation speed and the second rotation speed as a target value of the rotation speed of the first cylinder group, The second control unit sets the larger of the first rotation speed and the second rotation speed as a target value of the rotation speed of the second cylinder group.

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