JP2023121269A - Control system for internal combustion engine - Google Patents

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

The present disclosure relates to control systems for internal combustion engines.

Conventionally, a control system for an internal combustion engine that injects fuel into an intake port is known (see, for example, Patent Documents 1 and 2). As a system for injecting fuel into the intake port, there are a port injection system that forms a mixture in the intake port and a semi-direct injection system that directly injects fuel from the intake port into the cylinder. It is Patent documents 1 and 2 disclose a control system for a semi-direct injection type internal combustion engine.

Japanese Patent Application Laid-Open No. 2020-139410 Japanese Patent Application Laid-Open No. 2021-32131

In such an internal combustion engine that injects fuel into the intake port, the air-fuel ratio between the intake ports varies depending on the fuel adhering to the intake port. Patent Document 1 focuses on emissions of an internal combustion engine and discloses a control system for an internal combustion engine that injects one of two fuel injection valves during one cycle from an intake stroke to an exhaust stroke. Patent Document 2 focuses on early warm-up of a catalyst and discloses a control system for an internal combustion engine that injects one of two fuel injection valves. Therefore, in the internal combustion engine control systems of Patent Documents 1 and 2, one of the two fuel injection valves is in a state of not injecting fuel, and the air-fuel ratio between the intake ports may vary. Neither of Patent Literature 1 and Patent Literature 2 discloses a control system for an internal combustion engine that focuses on variations in the air-fuel ratio between intake ports.

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.

A 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, and a second injection valve arranged in the second intake port. a fuel injection valve, an engine temperature acquisition unit that acquires the temperature of the internal combustion engine, and a first intake air temperature and a first intake air amount that are arranged in the first intake port and that flow through the first intake port. a first port intake air detection unit; a second port intake air detection unit arranged at the second intake port for detecting a second intake air temperature and a second intake air amount of intake air flowing through the second intake port; and the internal combustion engine. and a control device for controlling the The control device uses the first intake air amount and the second intake air amount to change at least one of an injection amount of the first fuel injection valve and an injection amount of the second fuel injection valve. and second control for changing at least one of the injection amount of the first fuel injection valve and the injection amount of the second fuel injection valve using the first intake air temperature and the second intake air temperature. either one of the first control and the second control is preferentially executed based on the temperature of the internal combustion engine acquired by the engine temperature acquisition unit.

According to this control system for an internal combustion engine, one of the first control and the second control is preferentially executed based on the temperature of the internal combustion engine acquired from the engine temperature acquiring section, thereby controlling the first intake port. and variation in the air-fuel ratio of the second intake port can be suppressed.

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.

1 is a system diagram of an internal combustion engine control system according to an embodiment of the present disclosure; FIG. 2 is an enlarged view of a cylinder of an internal combustion engine according to embodiments of the present disclosure; FIG. 4 is a flow chart showing a control procedure of the control device according to the embodiment of the present disclosure;

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following specification, the upstream side with respect to the flow direction of intake air or exhaust gas is referred to as "upstream", and the downstream side is referred to as "downstream".

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 detection units 8, a temperature detection unit (an example of an engine temperature acquisition unit ) 10 and a control device 20 . The internal combustion engine 2 of this embodiment is a serial internal combustion engine 2 in which a plurality of cylinders (an example of a first cylinder) 10 are arranged in series. However, the arrangement and number of cylinders 11 can be changed. Specifically, the internal combustion engine 2 may be arranged such that the cylinders 11 are V-shaped or horizontally opposed. Also, the number of cylinders 11 may be about 1 to 12. Also, the internal combustion engine 2 of the present embodiment is a gasoline engine that ignites an air-fuel mixture (not shown) with a spark plug.

The internal combustion engine 2 of the present embodiment has an air cleaner 13 , a supercharger 14 and an intake manifold 17 , and intake air sucked from the air cleaner 13 is supercharged by a compressor 14 a of the supercharger 14 . The supercharged intake air is cooled by the 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 is supplied to the exhaust purification catalyst 18 via the turbine 14 b of the supercharger 14 . However, the internal combustion engine 2 may be an internal combustion engine 2 that does not have the supercharger 14 or the like.

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 4 a and the second intake port 4 b are arranged adjacent to each other in the direction in which the cylinders 11 are arranged and are connected to the same cylinder 11 . A port outlet of the first intake port 4a connected to the cylinder 11 is opened and closed by a first intake valve 12a. As with the first intake port 4a, the port outlet of the second intake port 4b connected to the cylinder 11 is opened and closed by the second intake valve 12b.

A fuel injection valve 6 is arranged in each of the first intake port 4a and the second intake port 4b. Specifically, a first fuel injection valve 6a is arranged in the first intake port 4a, and a second fuel injection valve 6b is arranged 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 the control device 20, and the control device 20 controls the fuel injection period and the fuel injection timing.

As shown in FIG. 2, the first fuel injection valve 6a has an injection hole for injecting fuel arranged closer to the cylinder 11 than the upstream end 2c of the port wall 2b. Fuel is injected toward the cylinder 11. Similar to the first fuel injection valve 6a, the second fuel injection valve 6b has an injection hole for injecting fuel arranged closer to the cylinder 11 than the upstream end 2c of the port wall 2b, and the second intake valve 12b Fuel is injected toward the cylinder 11 when the valve is opened. That is, the internal combustion engine 2 of the present embodiment is a semi-direct injection type internal combustion engine 2 capable of forming an air-fuel mixture in the first intake port 4a and the second intake port 4b and also injecting fuel into the cylinders 11 as well.

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

In this embodiment, the port intake detection unit 8 is arranged in each of the first intake port 4a and the second intake port 4b. Specifically, a first port intake detection section 8a is arranged in the first intake port 4a, and a second port intake detection section 8b is arranged in the second intake port 4b. The first port intake air detecting portion 8a is attached near the tip of the first fuel injection valve 6a, and the second port intake air detecting portion 8b is attached near the tip of the second fuel injection valve 6b. Thereby, the first port intake air detection unit 8a can detect the first intake air temperature Ti1 of the first intake port 4a and the first intake air amount Q1. The second port intake air detection unit 8b can detect a second intake air temperature Ti2 of the second intake port 4b and a second intake air amount Q2.

As shown in FIG. 1, the temperature detection unit 10 in this embodiment 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 cooling water flowing through the cylinder head 2 a of the internal combustion engine 2 and a cylinder block (not shown) and transmits the temperature to the control device 20 . However, the temperature detection unit 10 may be an oil temperature sensor that detects the temperature of oil filled in the internal combustion engine 2 and transmits the temperature to the control device 20, for example. Alternatively, the engine temperature Te may be acquired by the controller 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.

The control device 20 is a device that detects an 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 the target intake air amount Qt and the target air-fuel ratio AFt based on the accelerator opening Th. The control device 20 determines the target fuel injection amount P based on the target intake air amount Qt so that the air-fuel ratio of the air-fuel mixture supplied to the cylinder 11 becomes the target air-fuel ratio AFt. Then, the control device 20 detects the first intake air temperature Ti1 and the second intake air temperature Ti2 detected by the first port intake air detection section 8a and the second port intake air detection section 8b, or the first intake air amount Q1 and the second intake air amount Q2. Then, the target fuel injection amount P is determined. Specifically, of the target fuel injection amount P, the first target fuel injection amount (an example of the injection amount of the first fuel injection valve 6a) P1 injected by the first fuel injection valve 6a and the second fuel injection valve 6b A second target fuel injection amount to be injected (an example of the injection amount of the second fuel injection valve 6b) P2 is determined.

In addition, based on values obtained from sensors such as the port intake detection unit 8, the temperature detection unit 10, the air flow sensor 22, and the accelerator position sensor 30a, the control device 20 controls the internal combustion engine 2 to achieve a desired operating state. Control of 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, the boost pressure of the supercharger 14, etc. may be executed. The control device 20 is actually an ECU (Electronic Control Unit) configured by a microcomputer including an arithmetic device, a memory, an input/output buffer, and the like. The control device 20 controls each device based on the map and program stored in the memory so that the internal combustion engine 2 is in a desired operating state. Various controls are not limited to processing by software, and can be processed by dedicated hardware (electronic circuits).

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

At 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. At step S2, the control device 20 determines whether or not the engine temperature Te is lower than a predetermined temperature Td.

Here, the predetermined temperature Td is the temperature at which the adhered fuel adhering to the port wall 2b is vaporized. 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 difficult to evaporate. Therefore, variations in the air-fuel ratio between the first intake port 4a and the second intake port 4b are less likely to occur. Therefore, the control device 20 can determine the first target fuel injection amount P1 and the second target fuel injection amount P2 without considering the adhering fuel amount. 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.

Therefore, when the control device 20 determines in step S2 that the engine temperature Te is lower than the predetermined temperature Td (step S2 YES), the process proceeds to step S3, and the control device 20 controls the first intake air amount Q1 and the second intake air amount Q1. Obtain the quantity Q2. After acquiring the first intake air amount Q1 and the second intake air amount Q2, the control device 20 proceeds to step S4.

In steps S4 to S7, the control device 20 uses the first intake air amount Q1 and the second intake air amount Q2 to change at least one of the first target fuel injection amount P1 and the second target fuel injection amount P2. Execute the first control.

In this embodiment, the control device 20 compares the first intake air amount Q1 and the second intake air amount Q2 in step S4 to determine whether the first intake air amount Q1 is greater than the second intake air amount Q2. When the control device 20 determines that the first intake air amount Q1 is larger than the second intake air amount Q2 (step S4 YES), the process 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.

The increment P1i by which the first target fuel injection amount P1 is increased is obtained, for example, by calculating the difference between the first intake air amount Q1 and the second intake air amount Q2 in the current cycle, and increasing the target fuel injection amount P by the amount corresponding to the difference. P1i may be added to calculate the next first target fuel injection amount P1n, which is the first target fuel injection amount P1 for the next cycle. Then, the control device 20 may inject the next first target fuel injection amount P1n in the next cycle. The controller 20 may set the amount of decrease P2d by which the second target fuel injection amount P2 is decreased to be 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 for the next cycle. The control device 20 may inject the next second target fuel injection amount P2n in the next cycle.

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 the increment P1i and the decrement P2d of the target fuel injection amount P according to the ratio. good. In any case, the control device 20 should be able to increase the first target fuel injection amount P1 and decrease the second target fuel injection amount P2 in step S5.

When the control device 20 determines 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, it is determined whether or not the first intake air amount Q1 is smaller than the second intake air amount Q2. When the controller 20 determines in step S6 that the first intake air amount Q1 is smaller than the second intake air amount Q2 (step S6 YES), the process proceeds to step S7. In step S7, the control device 20 decreases the first target fuel injection amount P1 and increases the second target fuel injection amount P2. The amount of decrease P1d and the amount of increase P2i at this time are the same as the calculation method in step S5, so the description thereof is omitted. When the control device 20 executes the process of step S5, determines in step S6 that the first intake air amount Q1 is larger than the second intake air amount Q2 (step S6 NO), and executes the process of step S7, it proceeds to step S1. proceed.

Thus, in the first control, when the second intake air amount Q2 decreases, the control device 20 decreases the next second target fuel injection amount P2n of the fuel injection timing in the next cycle, and the next first target fuel injection Increase the quantity P1n. Conversely, when the first intake air amount Q1 decreases, the next first target fuel injection amount P1n of the fuel injection timing in the next cycle is decreased, and the next second target fuel injection amount P2n is increased. Note that the control device 20 does not have to change the next-time first target fuel injection amount P1n and the next-time second target fuel injection amount P2n when there is no change in the first intake air amount Q1 and the second intake air amount Q2.

In this manner, when the engine temperature Te is lower than the predetermined temperature Td, the control device 20 preferentially executes the first control, thereby reducing the air space between the first intake port 4a and the second intake port 4b. Variation in the fuel ratio can be suppressed.

When the control device 20 determines in step S2 that the engine temperature Te is equal to or higher than the predetermined temperature Td (step S2 NO), the process proceeds to step S8. At a predetermined temperature Td or higher, the fuel adhering to the port wall 2b is vaporized, and the heat of vaporization lowers the intake air temperature Ti. Therefore, the air-fuel ratio tends 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 in consideration of the adhering fuel. Therefore, the control device 20 uses the first intake air temperature Ti1 and the second intake air temperature Ti2 to determine the first target fuel injection amount P1 and the second target fuel injection amount P2.

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 proceeds to step S9.

In steps S9 to S12, the control device 20 uses the first intake air temperature Ti1 and the second intake air temperature Ti2 to change at least one of the first target fuel injection amount P1 and the second target fuel injection amount P2. 2 control.

In this embodiment, the control device 20 determines whether or not the first intake air temperature Ti1 has decreased in step S9. For example, the control device 20 compares the first intake air temperature Ti1 and the second intake air temperature Ti2, and determines that the first intake air temperature Ti1 has decreased when the first intake air temperature Ti1 is lower than the second intake air temperature Ti2. may The control device 20 has a sensor (not shown) that detects the temperature of the intake manifold 17, compares the temperature acquired by this sensor with the first intake air temperature Ti1, and judges that the first intake air temperature Ti1 has decreased. good. Alternatively, the control device 20 may compare the airflow temperature Ta and determine 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 vaporized and was supplied to the cylinder 11.

Therefore, when the control device 20 determines that the first intake air temperature Ti1 has decreased (step S9 YES), the process proceeds to step S10 to decrease the first target fuel injection amount P1.

The decrease amount P1d for decreasing the first target fuel injection amount P1 is obtained by, for example, the control device 20 storing, as a map, an appropriate first fuel injection amount P1g, which is an appropriate fuel injection amount corresponding to the first intake air temperature Ti1. You can In this case, the control device 20 calculates the difference between the appropriate first fuel injection amount P1g and the first target fuel injection amount P1, and subtracts the difference from the next first target fuel injection amount P1n as the decrease amount P1d. good.

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 to determine 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 to decrease the second target fuel injection amount P2. Since the method of decreasing the second target fuel injection amount P2 is the same as that for the first target fuel injection amount P1, the description thereof will be omitted. After executing the processes of steps S10 and S12, control device 20 advances the process to step S1. When the control device 20 determines that the second intake air temperature Ti2 has not decreased (step S11 NO), the process proceeds to step S1. The control device 20 repeatedly executes such processing at predetermined intervals.

Thus, in the second control, when the first intake air temperature Ti1 decreases, the control device 20 reduces the next first target fuel injection amount P1n of the fuel injection timing in the next cycle. On the contrary, when the second intake air temperature Ti2 decreases, the next second target fuel injection amount P2n of the fuel injection timing in the next cycle is decreased.

In this manner, when the engine temperature Te is equal to or higher than the predetermined temperature Td, the control device 20 performs the second control preferentially, thereby correcting the air-fuel ratio that becomes richer due to the adhering fuel. and the second intake port 4b.

As described above, according to the control system 1 for the internal combustion engine 2, priority is given to 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. By doing so, it is possible to suppress variations in the air-fuel ratio between the first intake port 4a and the second intake port 4b.

<Other embodiments>
Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. In particular, multiple modifications described herein can be arbitrarily combined as required.

For example, in the embodiment described above, 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 to this. For example, the control of the present disclosure may be applied to suppress air-fuel ratio variations between the intake port 4 connected to the cylinder 11 and the intake port 4 connected to the adjacent cylinder 11 . It may also be applied to a plug-in hybrid electric vehicle (PHEV) capable of external charging or external power supply.

1: control system, 2: internal combustion engine 4: intake port, 4a: first intake port, 4b: second intake port 6: fuel injection valve, 6a: first fuel injection valve, 6b: second fuel injection valve 8: port intake detector,
8a: 1st port intake air detector 8b: 2nd port intake air detector 10: temperature detector 11: cylinder 20: controller 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: first intake air amount Q2: second intake air amount Td: predetermined temperature Te: engine temperature Ti1: first intake air temperature Ti2: second intake air temperature

Claims (6)

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 air detection unit arranged in the first intake port for detecting a first intake air temperature and a first intake air amount of intake air flowing through the first intake port;
a second port intake air detection unit arranged in the second intake port for detecting a second intake air temperature and a second intake air amount of intake air flowing through the second intake port;
a control device that controls the internal combustion engine;
with
The control device is
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;
second control for changing at least one of the injection amount of the first fuel injection valve and the injection amount of the second fuel injection valve using the first intake air temperature and the second intake air temperature;
including
Based on the temperature of the internal combustion engine acquired by the engine temperature acquiring unit, one of the first control and the second control is preferentially executed.
Control system for internal combustion engines. The internal combustion engine has a first cylinder,
The first intake port and the second intake port are connected to the first cylinder,
A control system for an internal combustion engine according to claim 1. The control device prioritizes the first control when the temperature of the internal combustion engine acquired by the engine temperature acquisition unit is less than a predetermined temperature.
3. A control system for an internal combustion engine according to claim 1 or 2. In the first control, when the first intake air amount decreases, the control device reduces the injection amount of the first fuel injection valve at the next fuel injection timing, and reduces the injection amount of the second fuel injection valve. to increase the
A control system for an internal combustion engine according to any one of claims 1 to 3. 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.
A control system for an internal combustion engine according to any one of claims 1 to 4. In the second control, when the first intake air temperature decreases, the control device reduces the injection amount of the first fuel injection valve at the next fuel injection timing.
A control system for an internal combustion engine according to any one of claims 1 to 5.