Internal combustion engine control system

Abstract

To provide a control system for an internal combustion engine capable of suppressing a difference in air-fuel ratios between intake ports.SOLUTION: A control system includes: a first fuel injection valve disposed in a first intake port; a second fuel injection valve disposed in a second intake port; an engine temperature acquisition section that acquires a temperature of an internal combustion engine; a first port intake air detection section that detects a first intake temperature and first intake amount of intake air flowing in the first intake port; a second port intake air detection section that detects a second intake temperature and second intake amount of intake air flowing in the second intake port; and a control device that controls the internal combustion engine. The control device includes first control for changing at least either one of injection amounts of the first and second fuel injection valves by using the first and second intake amounts and second control for changing at least either one of injection amounts of the first and second fuel injection valves by using the first and second intake temperatures, and preferentially executes at least either one of the first control or the second control on the basis of a temperature of the internal combustion engine.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to control systems for internal combustion engines. [Background technology]

[0002] Conventionally, there has been known a control system for an internal combustion engine that injects fuel into an intake port (see, for example, Patent Document 1 and Patent Document 2). As such a system for injecting fuel into an intake port, there are known a port injection system that forms an air-fuel mixture in the intake port, and a semi-direct injection system that directly injects fuel from the intake port into the cylinder. Patent Document 1 and Patent Document 2 disclose a control system for an internal combustion engine that uses a semi-direct injection system. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-139410 A [Patent Document 2] Patent Publication No. 2021-32131 Summary of the Invention [Problem to be solved by the invention]

[0004] In such an internal combustion engine injecting fuel into the intake port, the fuel adhering to the intake port causes variation in the air-fuel ratio between the intake ports. Patent Document 1 focuses on the emission of the internal combustion engine and discloses a control system for the internal combustion engine in which one of two fuel injection valves injects during one cycle from the intake stroke to the exhaust stroke. Patent Document 2 focuses on early warm-up of the catalyst and discloses a control system for the internal combustion engine in which one of two fuel injection valves injects. Therefore, in the control systems for the internal combustion engine of Patent Document 1 and Patent Document 2, one of the two fuel injection valves may not inject fuel, causing variation in the air-fuel ratio between the intake ports. Neither Patent Document 1 nor Patent Document 2 discloses a control system for the internal combustion engine that focuses on the variation in the air-fuel ratio between the intake ports.

[0005] An object of the present disclosure is to provide a control system for an internal combustion engine that can suppress variations in air-fuel ratio between intake ports. [Means for solving the problem]

[0006] The control system for an internal combustion engine according to the present disclosure includes a first intake port, a second intake port, a first fuel injection valve arranged in the first intake port, a second fuel injection valve arranged in the second intake port, an engine temperature acquisition unit that acquires the temperature of the internal combustion engine, a first port intake detection unit arranged in the first intake port that detects a first intake temperature and a first intake volume of the intake air flowing into the first intake port, a second port intake detection unit arranged in the second intake port that detects a second intake temperature and a second intake volume of the intake air flowing into the second intake port, and a control device that controls the internal combustion engine. The control device includes a first control that uses the first intake air amount and the second intake air amount to change at least one of the injection amount of the first fuel injection valve and the injection amount of the second fuel injection valve, and a second control that uses the first intake air temperature and the second intake air temperature to change at least one of the injection amount of the first fuel injection valve and the injection amount of the second fuel injection valve, and executes either the first control or the second control with priority based on the temperature of the internal combustion engine acquired by the engine temperature acquisition unit.

[0007] According to this internal combustion engine control system, the variation in the air-fuel ratio of the first intake port and the second intake port can be suppressed by preferentially executing either the first control or the second control based on the temperature of the internal combustion engine acquired from the engine temperature acquisition unit. Effect of the Invention

[0008] According to the present disclosure, it is possible to provide a control system for an internal combustion engine that can suppress variations in air-fuel ratio between intake ports. [Brief description of the drawings]

[0009] [Figure 1] 1 is a system diagram of an internal combustion engine control system according to an embodiment of the present disclosure. [Diagram 2] 1 is a close-up view of a cylinder of an internal combustion engine according to an embodiment of the present disclosure. [Diagram 3] 4 is a flowchart showing a control procedure of a control device according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In the following description, the upstream side with respect to the flow direction of intake air or exhaust air will be referred to as "upstream" and the downstream side will be referred to as "downstream".

[0011] As shown in FIG. 1, a control system 1 for an internal combustion engine 2 includes a plurality of intake ports 4, a plurality of fuel injection valves 6, a plurality of port intake detectors 8, a temperature detector (an example of an engine temperature acquisition unit) 10, and a control device 20. The internal combustion engine 2 of this embodiment is an in-line type internal combustion engine 2 in which a plurality of cylinders (an example of a first cylinder) 10 are arranged in line. However, the arrangement and number of the cylinders 11 can be changed. Specifically, the internal combustion engine 2 may have the cylinders 11 arranged in a V-type or horizontally opposed type. The number of the cylinders 11 may range from about 1 to about 12. The internal combustion engine 2 of this embodiment is a gasoline engine that ignites an air-fuel mixture by a spark plug (not shown).

[0012] The internal combustion engine 2 of this embodiment has an air cleaner 13, a turbocharger 14, and an intake manifold 17, and the intake air drawn in from the air cleaner 13 is turbocharged by a compressor 14a of the turbocharger 14. The turbocharged intake air is cooled by an intercooler 15 and supplied to the intake port 4 via the intake manifold 17. The internal combustion engine 2 also has an exhaust valve 16 and an exhaust purification catalyst 18, and exhaust gas is supplied to the exhaust purification catalyst 18 via a turbine 14b of the turbocharger 14. However, the internal combustion engine 2 may be an internal combustion engine 2 that does not have the turbocharger 14 or the like.

[0013] As shown in FIG. 2, the intake port 4 is connected to each of the four cylinders 11. The intake port 4 is provided in the cylinder head 2a (see FIG. 1), and has a first intake port 4a and a second intake port 4b branched by a port wall 2b formed by the cylinder head 2a. The first intake port 4a and the second intake port 4b are arranged adjacent to each other in the arrangement direction of the cylinders 11, and are connected to the same cylinder 11. The first intake port 4a has a port outlet connected to the cylinder 11 that is opened and closed by a first intake valve 12a. The second intake port 4b has a port outlet connected to the cylinder 11 that is opened and closed by a second intake valve 12b, similar to the first intake port 4a.

[0014] The fuel injection valves 6 are disposed in the first intake port 4a and the second intake port 4b, respectively. Specifically, the first fuel injection valve 6a is disposed in the first intake port 4a, and the second fuel injection valve 6b is disposed in the second intake port 4b. As shown in Figs. 1 and 2, the first fuel injection valve 6a and the second fuel injection valve 6b are supplied with fuel from a delivery pipe 6c. The first fuel injection valve 6a and the second fuel injection valve 6b are each electrically connected to a control device 20, and the control device 20 controls the fuel injection period and the fuel injection timing.

[0015] 2, the first fuel injection valve 6a has a nozzle hole for injecting fuel arranged closer to the cylinder 11 than the upstream end 2c of the port wall 2b, and injects fuel toward the cylinder 11 when the first intake valve 12a is open. The second fuel injection valve 6b, like the first fuel injection valve 6a, has a nozzle hole for injecting fuel arranged closer to the cylinder 11 than the upstream end 2c of the port wall 2b, and injects fuel toward the cylinder 11 when the second intake valve 12b is open. That is, the internal combustion engine 2 of this embodiment is a semi-direct injection type internal combustion engine 2 that forms an air-fuel mixture in the first intake port 4a and the second intake port 4b and is also capable of injecting fuel into the cylinder 11.

[0016] The port intake detection unit 8 is a sensor that detects the intake air temperature Ti and the intake air amount Qr flowing through the intake port 4. In this embodiment, the port intake detection unit 8 detects the intake air temperature Ti, converts the detected intake air temperature Ti into a signal, and transmits it to the control device 20. The control device 20 converts the signal based on the intake air temperature Ti into the intake air amount Qr based on a stored map. However, the port intake detection unit 8 may be a sensor that detects the intake air temperature Ti and the intake air amount Qr separately.

[0017] In this embodiment, the port intake detector 8 is disposed in each of the first intake port 4a and the second intake port 4b. Specifically, the first port intake detector 8a is disposed in the first intake port 4a, and the second port intake detector 8b is disposed in the second intake port 4b. The first port intake detector 8a is attached near the tip of the first fuel injection valve 6a, and the second port intake detector 8b is attached near the tip of the second fuel injection valve 6b. This allows the first port intake detector 8a to detect the first intake temperature Ti1 and the first intake amount Q1 of the first intake port 4a. The second port intake detector 8b can detect the second intake temperature Ti2 and the second intake amount Q2 of the second intake port 4b.

[0018] As shown in FIG. 1, in this embodiment, the temperature detection unit 10 is a sensor that detects the engine temperature Te of the internal combustion engine 2. The engine temperature Te is a value that indicates the temperature state of the internal combustion engine 2. In this embodiment, the temperature detection unit 10 is a water temperature sensor that detects the temperature of the cooling water flowing through the cylinder head 2a and a cylinder block (not shown) of the internal combustion engine 2 and transmits the temperature to the control device 20. However, the temperature detection unit 10 may be, for example, an oil temperature sensor that detects the temperature of the oil filled in the internal combustion engine 2 and transmits the temperature to the control device 20. In addition, the engine temperature Te may be obtained by the control device 20 estimating the engine temperature Te of the internal combustion engine 2 based on the airflow temperature Ta detected by the airflow sensor 22, for example. In any case, any method may be used as long as the control device 20 can obtain the engine temperature Te.

[0019] The control device 20 detects the accelerator opening Th from an accelerator position sensor 30a attached to an accelerator pedal 30, and controls the internal combustion engine 2 according to the accelerator opening Th. In this embodiment, the control device 20 determines a target intake air amount Qt and a target air-fuel ratio AFt based on the accelerator opening Th. The control device 20 determines a target fuel injection amount P based on the target intake air amount Qt so that the air-fuel ratio of the mixture supplied to the cylinder 11 becomes the target air-fuel ratio AFt. The control device 20 determines the target fuel injection amount P based on the first intake air temperature Ti1 and the second intake air temperature Ti2, or the first intake air amount Q1 and the second intake air amount Q2, detected by the first port intake detection unit 8a and the second port intake detection unit 8b. Specifically, of the target fuel injection amount P, a first target fuel injection amount P1 (an example of the injection amount of the first fuel injection valve 6a) to be injected by the first fuel injection valve 6a and a second target fuel injection amount P2 (an example of the injection amount of the second fuel injection valve 6b) to be injected by the second fuel injection valve 6b are determined.

[0020] In addition, the control device 20 may control each device, such as the throttle valve 24, the injection timing and injection period of the fuel injection valve 6, the valve overlap of the intake valve 12 and the exhaust valve 16, and the supercharging pressure of the supercharger 14, so that the internal combustion engine 2 is in a desired operating state, based on values ​​acquired from sensors such as the port intake detection unit 8, the temperature detection unit 10, the airflow sensor 22, and the accelerator position sensor 30a. The control device 20 is actually an ECU (Electronic Control Unit) configured by a microcomputer including a calculation device, a memory, an input / output buffer, and the like. The control device 20 controls each device so that the internal combustion engine 2 is in a desired operating state, based on maps and programs stored in the memory. Note that the various controls are not limited to processing by software, and can also be processed by dedicated hardware (electronic circuits).

[0021] Next, a control procedure executed by the control device 20 will be described with reference to the flowchart of Fig. 3. The control device 20 starts the control procedure when an ignition switch (not shown) is turned on.

[0022] In step S1, the control device 20 acquires the engine temperature Te. After acquiring the engine temperature Te, the control device 20 advances the process to step S2. In step S2, the control device 20 determines whether the engine temperature Te is lower than a predetermined temperature Td.

[0023] Here, the predetermined temperature Td is the temperature at which the fuel adhering to the port wall 2b vaporizes. For example, when the internal combustion engine 2 is in a cold state (for example, the value of the water temperature sensor is 80°C or less), the fuel adhering to the port wall 2b is unlikely to vaporize. Therefore, the air-fuel ratio is unlikely to vary between the first intake port 4a and the second intake port 4b. Therefore, the control device 20 can determine the first target fuel injection amount P1 and the second target fuel injection amount P2 without taking the amount of adhering fuel into consideration. Therefore, the control device 20 can determine the first target fuel injection amount P1 and the second target fuel injection amount P2 based on the first intake air amount Q1 and the second intake air amount Q2.

[0024] When the control device 20 determines in step S2 that the engine temperature Te is lower than the predetermined temperature Td (YES in step S2), the control device 20 proceeds to step S3, where the control device 20 acquires the first intake air amount Q1 and the second intake air amount Q2. After acquiring the first intake air amount Q1 and the second intake air amount Q2, the control device 20 proceeds to step S4.

[0025] In steps S4 to S7, the control device 20 executes a first control for changing at least one of the first target fuel injection amount P1 and the second target fuel injection amount P2, using the first intake air amount Q1 and the second intake air amount Q2.

[0026] In this embodiment, the control device 20 compares the first intake air amount Q1 and the second intake air amount Q2 in step S4, and determines whether the first intake air amount Q1 is greater than the second intake air amount Q2. If the control device 20 determines that the first intake air amount Q1 is greater than the second intake air amount Q2 (YES in step S4), the control device 20 proceeds to step S5. In step S5, the control device 20 increases the first target fuel injection amount P1 and decreases the second target fuel injection amount P2.

[0027] The increment P1i of the first target fuel injection amount P1 may be calculated by, for example, calculating the difference between the first intake amount Q1 and the second intake amount Q2 in the current cycle, and adding the increment P1i according to the difference to the target fuel injection amount P to calculate the next first target fuel injection amount P1n, which is the first target fuel injection amount P1 in the next cycle. Then, the control device 20 may inject the next first target fuel injection amount P1n in the next cycle. The control device 20 may set the decrement P2d of the second target fuel injection amount P2 to the same amount as P1i. The control device 20 may subtract the decrement P2d from the second target fuel injection amount P2 to calculate the next second target fuel injection amount P2n, which is the second target fuel injection amount P2 in the next cycle. The control device 20 may inject the next second target fuel injection amount P2n in the next cycle.

[0028] The control device 20 may, for example, calculate the ratio between the first intake air amount Q1 and the second intake air amount Q2 in the current cycle, and calculate an increase P1i and a decrease P2d according to the ratio in the target fuel injection amount P. In any case, it is sufficient for the control device 20 to increase the first target fuel injection amount P1 and decrease the second target fuel injection amount P2 in step S5.

[0029] When the control device 20 judges that the first intake air amount Q1 is not larger than the second intake air amount Q2 (step S4: NO), the process proceeds to step S6. In step S6, the control device 20 judges whether the first intake air amount Q1 is smaller than the second intake air amount Q2. When the control device 20 judges that the first intake air amount Q1 is smaller than the second intake air amount Q2 in step S6 (step S6: YES), the process proceeds to step S7. In step S7, the control device 20 reduces the first target fuel injection amount P1 and increases the second target fuel injection amount P2. The calculation method of the reduction amount P1d and the increase amount P2i at this time is the same as that in step S5, so the explanation is omitted. When the control device 20 judges that the first intake air amount Q1 is larger than the second intake air amount Q2 in step S5 and step S6 (step S6: NO), and when the control device 20 executes the process of step S7, the process proceeds to step S1.

[0030] In this way, in the first control, when the second intake air amount Q2 is decreased, the control device 20 decreases the next second target fuel injection amount P2n of the fuel injection timing in the next cycle and increases the next first target fuel injection amount P1n. Conversely, when the first intake air amount Q1 is decreased, the control device 20 decreases the next first target fuel injection amount P1n of the fuel injection timing in the next cycle and increases the next second target fuel injection amount P2n. Note that, when there is no change in the first intake air amount Q1 and the second intake air amount Q2, the control device 20 does not need to change the next first target fuel injection amount P1n and the next second target fuel injection amount P2n.

[0031] In this way, when the engine temperature Te is lower than the predetermined temperature Td, the control device 20 prioritizes execution of the first control, thereby suppressing variations in the air-fuel ratio between the first intake port 4a and the second intake port 4b.

[0032] When the control device 20 determines in step S2 that the engine temperature Te is equal to or higher than the predetermined temperature Td (NO in step S2), the control device 20 proceeds to step S8. At or higher than the predetermined temperature Td, the fuel adhering to the port wall 2b vaporizes, and the intake temperature Ti drops due to the heat of vaporization. For this reason, the air-fuel ratio is likely to vary between the first intake port 4a and the second intake port 4b. Therefore, the control device 20 needs to determine the first target fuel injection amount P1 and the second target fuel injection amount P2, taking into account the amount of adhering fuel. For this reason, the control device 20 determines the first target fuel injection amount P1 and the second target fuel injection amount P2 using the first intake temperature Ti1 and the second intake temperature Ti2.

[0033] Therefore, the control device 20 acquires the first intake air temperature Ti1 and the second intake air temperature Ti2 in step S8. After acquiring the first intake air temperature Ti1 and the second intake air temperature Ti2, the control device 20 advances the process to step S9.

[0034] In steps S9 to S12, the control device 20 executes a second control for changing at least one of the first target fuel injection amount P1 and the second target fuel injection amount P2 using the first intake air temperature Ti1 and the second intake air temperature Ti2.

[0035] In this embodiment, the control device 20 judges whether the first intake air temperature Ti1 has decreased in step S9. For example, the control device 20 may compare the first intake air temperature Ti1 with the second intake air temperature Ti2, and judge that the first intake air temperature Ti1 has decreased if the first intake air temperature Ti1 is lower than the second intake air temperature Ti2. The control device 20 may have a sensor (not shown) that detects the temperature of the intake manifold 17, and may compare the temperature acquired by this sensor with the first intake air temperature Ti1 to judge that the first intake air temperature Ti1 has decreased. Alternatively, the control device 20 may compare the first intake air temperature Ti1 with the air flow temperature Ta and judge that the first intake air temperature Ti1 has decreased. In any case, when the first intake air temperature Ti1 has decreased, there is a possibility that the fuel adhering to the port wall 2b of the first intake port 4a has vaporized and the adhering fuel has been supplied to the cylinder 11.

[0036] Therefore, when the control device 20 determines that the first intake air temperature Ti1 has decreased (YES in step S9), the control device 20 advances the process to step S10, and reduces the first target fuel injection amount P1.

[0037] The reduction amount P1d by which the first target fuel injection amount P1 is reduced may be determined by, for example, storing an appropriate first fuel injection amount P1g, which is an appropriate fuel injection amount according to the first intake air temperature Ti1, as a map in the control device 20. In this case, the control device 20 may calculate the difference between the appropriate first fuel injection amount P1g and the first target fuel injection amount P1, and subtract the difference as the reduction amount P1d from the next first target fuel injection amount P1n.

[0038] When the control device 20 determines that the first intake air temperature Ti1 has not decreased (step S9 NO), the process proceeds to step S11, where the control device 20 determines whether the second intake air temperature Ti2 has decreased. When the control device 20 determines that the second intake air temperature Ti2 has decreased (step S11 YES), the process proceeds to step S12, where the control device 20 reduces the second target fuel injection amount P2. The method of reducing the second target fuel injection amount P2 is similar to that of the first target fuel injection amount P1, and therefore the description is omitted. After executing the processes of steps S10 and S12, the control device 20 proceeds to step S1. When the control device 20 determines that the second intake air temperature Ti2 has not decreased (step S11 NO), the control device 20 proceeds to step S1. The control device 20 repeatedly executes such processes at predetermined intervals.

[0039] In this way, in the second control, when the first intake air temperature Ti1 decreases, the control device 20 decreases the next first target fuel injection amount P1n for the fuel injection timing in the next cycle. Conversely, when the second intake air temperature Ti2 decreases, the control device 20 decreases the next second target fuel injection amount P2n for the fuel injection timing in the next cycle.

[0040] In this way, when the engine temperature Te is equal to or higher than a predetermined temperature Td, the control device 20 performs the second control with priority, thereby correcting the air-fuel ratio that becomes rich due to adhering fuel and suppressing the variation in the air-fuel ratio between the first intake port 4a and the second intake port 4b.

[0041] As described above, according to the control system 1 for the internal combustion engine 2, the variation in the air-fuel ratio between the first intake port 4a and the second intake port 4b can be suppressed by preferentially executing either the first control or the second control based on the engine temperature Te of the internal combustion engine 2 acquired by the temperature detection unit 10.

[0042] <Other embodiments> Although the embodiment of the present disclosure has been described above, the present disclosure is not limited to the above embodiment, and various modifications are possible without departing from the gist of the invention. In particular, the multiple modifications described in this specification can be arbitrarily combined as necessary.

[0043] For example, in the above embodiment, the first intake port 4a and the second intake port 4b connected to one cylinder 11 are used as an example, but the present disclosure is not limited thereto. For example, the control of the present disclosure may be applied to suppress the variation in the air-fuel ratio between the intake port 4 connected to the cylinder 11 and the intake port 4 connected to the adjacent cylinder 11. Also, the control may be applied to a plug-in hybrid electric vehicle (PHEV) capable of external charging or external power supply. [Explanation of symbols]

[0044] 1: Control system, 2: Internal combustion engine 4: Intake port, 4a: First intake port, 4b: Second intake port 6: fuel injector, 6a: first fuel injector, 6b: second fuel injector 8: Port intake detector, 8a: First port intake detector, 8b: Second port intake detector 10: Temperature detection unit, 11: Cylinder, 20: Control device P1: First target fuel injection amount, P1n: Next first target fuel injection amount P2: second target fuel injection amount, P2n: next second target fuel injection amount Q1: 1st intake volume, Q2: 2nd intake volume Td: Predetermined temperature Te: Engine temperature Ti1: 1st intake air temperature, Ti2: 2nd intake air temperature

Claims

1. A first intake port; A second intake port; a first fuel injection valve disposed in the first intake port; a second fuel injection valve disposed in the second intake port; an engine temperature acquisition unit that acquires a temperature of the internal combustion engine; a first port intake detection unit disposed in the first intake port and configured to detect a first intake temperature and a first intake amount of the intake air flowing into the first intake port; a second port intake detection unit disposed in the second intake port and configured to detect a second intake air temperature and a second intake air amount of the intake air flowing into the second intake port; A control device for controlling the internal combustion engine; Equipped with The control device includes: a first control that changes at least one of an injection amount of the first fuel injection valve and an injection amount of the second fuel injection valve by using the first intake air amount and the second intake air amount; a second control for changing at least one of an injection amount of the first fuel injection valve and an injection amount of the second fuel injection valve by using the first intake air temperature and the second intake air temperature; Including, executes either the first control or the second control with priority based on the temperature of the internal combustion engine acquired by the engine temperature acquisition unit. Control system for internal combustion engines.

2. the internal combustion engine has a first cylinder, the first intake port and the second intake port are connected to the first cylinder.

2. The control system for an internal combustion engine according to claim 1.

3. The control device prioritizes the first control when the temperature of the internal combustion engine acquired by the engine temperature acquisition unit is lower than a predetermined temperature.

3. A control system for an internal combustion engine according to claim 1 or 2.

4. When the first intake amount is decreased in the first control, the control device reduces an injection amount of the first fuel injection valve and increases an injection amount of the second fuel injection valve at a next fuel injection timing.

4. A control system for an internal combustion engine according to claim 1.

5. The control device prioritizes the second control when the temperature of the internal combustion engine acquired by the engine temperature acquisition unit is equal to or higher than a predetermined temperature.

5. A control system for an internal combustion engine according to claim 1.

6. When the first intake air temperature is decreased, the control device reduces an injection amount of the first fuel injection valve at a next fuel injection timing in the second control. A control system for an internal combustion engine according to any one of claims 1 to 5.

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