JP2022075103A - Control system of vehicle and program - Google Patents

Abstract

To suppress the lowering of a temperature of a filter during the execution of filter regeneration processing, and to prevent the deterioration of fuel economy.SOLUTION: When a fuel cut condition is satisfied during the execution of filter regeneration processing by a filter regeneration processing control part 101, a fuel cut processing control part 102 performs fuel cut processing in a state that an EGR valve control part 103 sets an EGR valve 11 in a prescribed opening. By this constitution, since a high-temperature exhaust gas of an exhaust path 3 can be supplied to a filter 7 even if a fuel cut is performed, and a temperature of the filter 7 can be maintained high, the lowering of the temperature of the filter 7 during the execution of the filter regeneration processing can be suppressed, and the elongation of a time necessary for a finish of the filter regeneration processing can be suppressed. By executing the fuel cut processing during the execution of the filter regeneration processing, the wasteful fuel consumption is suppressed and the deterioration of fuel economy can be prevented.SELECTED DRAWING: Figure 1

Description

The present invention relates to a vehicle control system and a program for controlling a vehicle equipped with an internal combustion engine.

Some vehicles equipped with an internal combustion engine are equipped with a filter that collects particulate matter (PM: Particulate matter) in the exhaust gas generated by the internal combustion engine. In this case, in order to eliminate the state of clogging of the filter due to the collected particulate matter, a temperature raising process of the filter called a filter regeneration process is executed.

For example, in Patent Document 1, some cylinders among a plurality of cylinders are defined as lean combustion cylinders having an air-fuel ratio leaner than the stoichiometric air-fuel ratio, and are different from some cylinders among the plurality of cylinders. It is disclosed that the temperature rise process of the filter is performed by the dither control for operating the fuel injection device so that the air-fuel ratio is richer than the stoichiometric air-fuel ratio. Further, Patent Document 1 discloses a configuration that prohibits a fuel cut process for stopping fuel injection by a fuel injection valve on condition that dither control is executed. This suppresses the temperature of the gas flowing into the filter from dropping as compared to the case where the fuel cut process is not prohibited, making it easier to keep the temperature of the filter high, and the time required to complete the filter regeneration process. It can suppress the lengthening.

Japanese Unexamined Patent Publication No. 2019-85965 Japanese Unexamined Patent Publication No. 2019-44670

However, in Patent Document 1, it is assumed that the fuel cut process is prohibited (that is, the fuel cut process is not executed) at the timing when the fuel cut process should be originally executed, and there is a concern that the fuel consumption may be deteriorated.

The present invention has been made in view of such circumstances, and an object of the present invention is to suppress a decrease in the temperature of the filter during execution of the filter regeneration process and to prevent deterioration of fuel efficiency.

The vehicle control system of the present invention is a vehicle control system that controls a vehicle equipped with an internal combustion engine to which an intake path and an exhaust path are connected, and is installed in the exhaust path to capture particulate matter in exhaust gas. A purification device having a collecting filter, an EGR passage that is connected to the downstream side of the exhaust path to the downstream side of the purification device to return the exhaust gas to the intake path, and a flow rate of the exhaust gas that returns to the intake path are adjusted. An EGR system having an EGR valve, a filter regeneration processing control means for controlling the filter regeneration processing for the filter, a fuel cut processing control means for controlling the fuel cut processing for cutting the fuel supply to the internal combustion engine, and the EGR valve. EGR valve control means for controlling the opening and closing of the EGR valve is provided, and when the fuel cut condition is satisfied during execution of the filter regeneration process by the filter regeneration process control means, the EGR valve control means opens the EGR valve to a predetermined opening degree. The fuel cut processing control means executes the fuel cut processing in this state.

According to the present invention, it is possible to suppress a decrease in the temperature of the filter and prevent deterioration of fuel efficiency during the execution of the filter regeneration process.

It is a figure which shows the structure of the control system of the vehicle which concerns on embodiment. It is a flowchart which shows the example of the control process in the control system of the vehicle which concerns on embodiment. It is a timing chart which shows the example of the timing of the control process in the control system of the vehicle which concerns on embodiment.

The vehicle control system according to an embodiment of the present invention is a vehicle control system that controls a vehicle equipped with an internal combustion engine to which an intake path and an exhaust path are connected, and is installed in the exhaust path and in exhaust gas. A purification device having a filter for collecting particulate matter, an EGR passage that is connected to the downstream side of the exhaust path to the downstream side of the purification device and returns the exhaust gas to the intake path, and an exhaust gas that returns the exhaust gas to the intake path. An EGR system having an EGR valve for adjusting the flow rate, a filter regeneration processing control means for controlling the filter regeneration processing for the filter, and a fuel cut processing control means for controlling the fuel cut processing for cutting the fuel supply to the internal combustion engine. And the EGR valve control means for controlling the opening and closing of the EGR valve, and when the fuel cut condition is satisfied during the execution of the filter regeneration process by the filter regeneration process control means, the EGR valve control means is the EGR valve. The fuel cut processing control means executes the fuel cut process in a state where the opening degree is set to a predetermined value.
As a result, even if the fuel is cut, the exhaust gas having a high temperature in the exhaust path can be supplied to the filter, and the temperature of the filter can be kept high. Therefore, the filter can be regenerated during the execution of the filter regeneration process. It is possible to suppress the decrease in the temperature of the filter and prevent the time required to complete the filter regeneration process from becoming long. Further, since the fuel cut process is executed during the execution of the filter regeneration process, wasteful fuel consumption can be suppressed and deterioration of fuel efficiency can be prevented.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 shows a configuration of a vehicle control system according to an embodiment. The vehicle is an automobile equipped with an internal combustion engine 1.
Although a detailed description thereof is omitted, the internal combustion engine 1 burns fuel in a cylinder and obtains a driving force of a vehicle by using the combustion gas generated thereby. The internal combustion engine 1 is connected to an intake path 2 that introduces air into the internal combustion engine 1 and an exhaust path 3 that exhausts the exhaust gas generated by the internal combustion engine 1. In FIG. 1, the flow of exhaust gas is represented by an arrow. Further, a fuel injection device 4 for injecting fuel is installed in each cylinder of the internal combustion engine 1.

Further, a purification device 5 is installed in the exhaust path 3.
The purification device 5 has a catalyst 6 arranged on the upstream side and a filter 7 arranged on the downstream side. The catalyst 6 is a three-way catalyst or the like that purifies harmful substances in exhaust gas by oxidation and reduction. The filter 7 is a GPF (Gasoline Particulate Filter), a DPF (Diesel Particulate Filter), or the like that collects particulate matter in the exhaust gas.
Pressure sensors 8a and 8b are installed before and after the filter 7 (upstream side and downstream side). If the pressure difference before and after the filter 7 measured by the pressure sensors 8a and 8b is large, it can be detected that the filter 7 is in a clogged state.

In addition, an EGR (Exhaust Gas Recirculation) system 9 is installed.
The EGR system 9 has an EGR passage 10 and an EGR valve 11. The EGR passage 10 is connected to the downstream side of the exhaust path 3 with respect to the purification device 5, and the exhaust gas is returned to the intake path 2. The EGR valve 11 adjusts the flow rate of the exhaust gas returned to the intake path 2 by adjusting the opening degree thereof. With the EGR system 9 in this way, it is possible to reduce nitrogen oxides and improve fuel efficiency.

Further, the exhaust valve 12 is installed on the downstream side of the exhaust path 3 from the connection position of the EGR passage 10.

Next, the control device 100 mounted on the vehicle will be described.
As shown in FIG. 1, the control device 100 includes a filter regeneration processing control unit 101, a fuel cut processing control unit 102, an EGR valve control unit 103, and an exhaust valve control unit 104.

The filter regeneration processing control unit 101 controls the filter regeneration processing for the filter 7 of the purification device 5. When the pressure difference before and after the filter 7 measured by the pressure sensors 8a and 8b exceeds a predetermined threshold value, the filter regeneration processing control unit 101 assumes that the filter 7 is in a clogged state and executes the filter regeneration processing. Further, when a predetermined condition is satisfied, the filter regeneration processing control unit 101 stops the executing filter regeneration processing.

As for the filter regeneration process, a known one may be used (for example, Patent Documents 1, 2, etc.), and detailed description thereof will be omitted here. Generally, the filter is supplied with an unburned air-fuel mixture, rich exhaust gas and lean exhaust gas, the temperature of the filter is raised, and particulate matter deposited on the filter is burnt and removed. For example, there is a method of supplying an unburned air-fuel mixture to a filter by not igniting it during operation to raise the temperature of the filter. Alternatively, there is a method in which the filter is made rich and lean for each cylinder, and the unburned component is supplied to the filter to raise the temperature of the filter.
Further, an example of determining whether or not to execute the filter regeneration process based on the pressure difference before and after the filter 7 has been described, but the present invention is not limited to this. For example, the deposited amount of the particulate matter of the filter 7 may be estimated using a predetermined calculation formula, and it may be determined whether or not to execute the filter regeneration process based on the estimated amount.

The fuel cut processing control unit 102 controls the fuel cut processing for cutting the fuel supply by the fuel injection device 4. The fuel cut processing control unit 102 has a determination unit 102a that determines whether or not to execute the fuel cut process, and also determines whether or not to stop the running fuel cut process. The determination unit 102a determines whether to execute or stop the fuel cut process based on the fuel cut condition and the fuel cut stop condition. Specifically, when a state in which the accelerator pedal 13 is not operated due to deceleration (accelerator pedal off) is detected, it is determined that the fuel cut process is executed. Further, if the acceleration operation by the accelerator pedal 13 is detected during the execution of the fuel cut process, it is determined that the fuel cut process is stopped.

The EGR valve control unit 103 controls the opening and closing of the EGR valve 11 of the EGR system 9. The EGR valve control unit 103 normally adjusts the opening degree of the EGR valve 11 according to the operating state of the internal combustion engine 1. For example, the EGR valve 11 is set so that the flow rate of the exhaust gas returned to the intake path 2 becomes a target value according to the operating state (rotation speed, boost pressure, temperature of each part, load, intake air amount, etc.) of the internal combustion engine 1. The opening is feedback controlled. The normal time refers to a time other than the time when the fuel cut process is controlled during the execution of the filter regeneration process, as described in the flowchart of FIG. 2 described later.

The exhaust valve control unit 104 controls the opening and closing of the exhaust valve 12. The exhaust valve control unit 104 normally opens the exhaust valve 12 at a constant opening degree, for example, fully open. The normal time refers to a time other than the time when the fuel cut process is controlled during the execution of the filter regeneration process, as described in the flowchart of FIG. 2 described later.

In the control device 100 as described above, when the fuel cut condition is satisfied during the execution of the filter regeneration process by the filter regeneration process control unit 101, the EGR valve control unit 103 opens the EGR valve 11 in a predetermined manner, as will be described later. Further, the fuel cut processing control unit 102 executes the fuel cut processing in a state where the exhaust valve control unit 104 closes the valve so as to reduce the opening degree of the exhaust valve 12. As a result, it is possible to prevent the temperature of the filter from dropping during the execution of the filter regeneration process and to prevent deterioration of fuel efficiency.

The control device 100 as shown in FIG. 1 is composed of a computer device including, for example, a CPU, a ROM, a RAM, and the like, and the CPU executes a predetermined program stored in the ROM, for example, to function the respective units 101 to 104. Is realized. For example, the control device 100 may be realized as a function of the engine control module mounted on the vehicle.

Next, with reference to FIGS. 2 and 3, the control process by the control device 100 will be described in detail.
FIG. 2 is a flowchart showing an example of control processing in the vehicle control system according to the embodiment. The flowchart shown in FIG. 2 is executed during the execution of the filter reproduction process. Further, FIG. 3 is a timing chart showing an example of the timing of control processing in the vehicle control system according to the embodiment. In the example of FIG. ₃ , it is assumed that the execution of the filter regeneration process is started at the timing t1.

In step S1, the determination unit 102a of the fuel cut processing control unit 102 determines whether or not the fuel cut condition is satisfied, specifically, whether or not the accelerator pedal off is detected. If the fuel cut condition is satisfied, the process proceeds to step S2 in order to execute the fuel cut process. If the fuel cut condition is not satisfied, this process is repeated until the fuel cut condition is satisfied. In the example of FIG. 3, it is assumed that the fuel cut condition is satisfied at the timing t ₂ .

In step S2, the EGR valve control unit 103 sets the EGR valve 11 to a predetermined opening degree. As a result, the high-temperature exhaust gas of the exhaust path 3 can be supplied to the filter 7 via the EGR passage 10 and the intake path 2. The predetermined opening degree is set from the viewpoint of enabling the exhaust gas of the exhaust path 3 to be quickly supplied to the filter 7, and is, for example, the maximum opening degree at full throttle or normal time. In FIG. 3, it is assumed that the EGR valve 11 has a predetermined opening at the timing t ₂ when the fuel cut condition is satisfied, but in reality, from the issuance of the command until the opening of the EGR valve 11 is changed. Since it takes time, a time difference may occur.

In step S3, the exhaust valve control unit 104 closes the exhaust valve 12 so as to reduce the opening degree of the exhaust valve 12. By making the opening degree of the exhaust valve 12 smaller than the normal opening degree (constant opening degree), more exhaust gas flows from the exhaust path 3 to the EGR passage 10, so that the high temperature exhaust gas is used as the filter 7. It can be supplied efficiently. The predetermined opening degree of the EGR valve 11 and the opening degree due to the valve closing operation of the exhaust valve 12 are set based on the relationship between the capacity of the EGR system 9 and the capacity of the exhaust path 3. Note that FIG. 3 shows that the opening degree of the exhaust valve 12 is reduced at the timing t ₂ when the fuel cut condition is satisfied, but in reality, the opening degree of the exhaust valve 12 is changed after the command is issued. Since it takes time, a time difference may occur.

In step S4, the fuel cut processing control unit 102 executes the fuel cut processing. It is preferable that the timing t ₃ for executing the fuel cut process is later than the timing t ₂ for setting the EGR valve 11 to a predetermined opening degree. If the fuel cut process is executed before the timing t ₂ , the temperature of the exhaust gas becomes low, and the exhaust gas having the low temperature is supplied to the filter 7. Therefore, first, the EGR valve 11 is set to a predetermined opening degree so that the exhaust gas having a high temperature is supplied to the filter 7 via the EGR passage 10 and the intake path 2, and then the fuel cut process is executed.

In step S5, the determination unit 102a of the fuel cut processing control unit 102 determines whether or not the fuel cut stop condition is satisfied, specifically, whether or not the acceleration operation by the accelerator pedal 13 is detected. When the fuel cut stop condition is satisfied, the process proceeds to step S6 in order to stop the fuel cut process. If the fuel cut stop condition is not satisfied, this process is repeated until the fuel cut stop condition is satisfied. In the example of FIG. ₃ , it is assumed that the fuel cut stop condition is satisfied at the timing t4.

In step S6, the exhaust valve control unit 104 returns the exhaust valve 12 to the normal opening degree. In FIG. 3, it is assumed that the opening degree of the exhaust valve 12 is returned at the timing t ₄ when the fuel cut stop condition is satisfied, but in reality, the opening degree of the exhaust valve 12 is changed after the command is issued. Since it takes time, a time difference may occur.

In step S7, the EGR valve control unit 103 fully closes the EGR valve 11. In FIG. 3, it is assumed that the EGR valve 11 is fully closed at the timing t ₄ when the fuel cut stop condition is satisfied, but in reality, from the time when the command is issued until the opening degree of the EGR valve 11 is changed. Since it takes time, a time difference may occur.

In step S8, the fuel cut processing control unit 102 stops the fuel cut processing after a predetermined time has elapsed after the EGR valve 11 is fully closed in step S7 (timing t5 in FIG. ₃ ). The reason for waiting for a predetermined time to elapse after the EGR valve 11 is fully closed is to return the fuel cut state to the fuel supply state after scavenging the exhaust gas remaining in the EGR system 9. Unburned fuel may remain in the exhaust gas, and abnormal combustion of the internal combustion engine 1 can be suppressed by returning to the fuel supply state after sweeping the exhaust gas. The predetermined time may be obtained from, for example, the capacity of the EGR system 9 and the cycle of the internal combustion engine 1 required to scaveng it.

After step S8, the flow chart is exited. After exiting this flowchart, the EGR valve control unit 103 executes normal control and adjusts the opening degree of the EGR valve 11 according to the operating state of the internal combustion engine 1. Further, if the filter reproduction process is being executed, this flowchart is repeatedly executed.

The flowchart of FIG. 2 is based on the premise that the filter regeneration process is being executed, and if the filter regeneration process is stopped, the flowchart is exited. In that case, if the exhaust valve 12 is closed, the exhaust valve control unit 104 returns the exhaust valve 12 to the normal opening degree. Further, after exiting this flowchart, the EGR valve control unit 103 executes normal control and adjusts the opening degree of the EGR valve 11 according to the operating state of the internal combustion engine 1.

Further, although not described in the flowchart of FIG. 2, the temperature of the filter 7 is monitored by actual measurement or estimation, and the temperature of the filter 7 is predetermined when the fuel cut process is executed during the execution of the filter regeneration process. When the temperature drops below the above temperature, the fuel cut state may be restored to the fuel supply state.

As described above, when the fuel cut condition is satisfied during the execution of the filter regeneration process by the filter regeneration process control unit 101, the fuel cut process is performed with the EGR valve control unit 103 having the EGR valve 11 at a predetermined opening degree. The control unit 102 executes the fuel cut process. As described above, when the fuel cut is required during the execution of the filter regeneration process, the opening degree of the EGR valve 11 is set to a relatively large opening degree instead of opening and closing by feedback control as in the normal case. As a result, even if the fuel is cut, not only the cold air is supplied to the filter 7, but the exhaust gas having a high temperature in the exhaust path 3 can be supplied to the filter 7, and the temperature of the filter 7 is kept high. be able to. Therefore, it is possible to suppress a decrease in the temperature of the filter 7 during the execution of the filter regeneration process and to suppress a long time required for the completion of the filter regeneration process. Further, since the fuel cut process is executed during the execution of the filter regeneration process, wasteful fuel consumption can be suppressed and deterioration of fuel efficiency can be prevented.

Although the embodiments of the present invention have been described in detail with reference to the drawings, each embodiment merely shows a specific example in carrying out the present invention. The technical scope of the present invention is not limited to each embodiment. The present invention can be modified in various ways without departing from the spirit of the present invention, and these are also included in the technical scope of the present invention.
The present invention can also be realized by supplying software (program) to a system or device via a network or various storage media, and the computer of the system or device reads and executes the program.

1: Internal combustion engine, 2: Intake path, 3: Exhaust path, 4: Fuel injection device, 5: Purification device, 6: Catalyst, 7: Filter, 8a, 8b: Pressure sensor, 9: EGR system, 10: EGR passage , 11: EGR valve, 12: exhaust valve, 13: accelerator pedal, 100: control device. 101: Filter regeneration processing control unit, 102: Fuel cut processing control unit, 102a: Judgment unit, 103: EGR valve control unit, 104: Exhaust valve control unit

Claims (4)

A vehicle control system that controls a vehicle equipped with an internal combustion engine to which an intake path and an exhaust path are connected.
A purification device installed in the exhaust path and having a filter for collecting particulate matter in the exhaust gas,
An EGR system having an EGR passage connected to the downstream side of the exhaust path to the downstream side of the purification device to return the exhaust gas to the intake path and an EGR valve for adjusting the flow rate of the exhaust gas returning to the intake path.
A filter regeneration processing control means for controlling the filter regeneration processing for the filter,
A fuel cut processing control means for controlling a fuel cut process for cutting the fuel supply to the internal combustion engine, and a fuel cut process control means.
The EGR valve control means for controlling the opening and closing of the EGR valve is provided.
When the fuel cut condition is satisfied during the execution of the filter regeneration process by the filter regeneration process control means, the fuel cut process control means fuels the EGR valve control means with the EGR valve set to a predetermined opening degree. A vehicle control system characterized by performing a cut process. An exhaust valve installed downstream of the connection position of the EGR passage in the exhaust path,
The exhaust valve control means for controlling the opening and closing of the exhaust valve is provided.
When the fuel cut condition is satisfied during the execution of the filter regeneration process by the filter regeneration process control means, the exhaust valve control means operates to close the valve so as to reduce the opening degree of the exhaust valve. The vehicle control system according to claim 1. When the fuel cut stop condition is satisfied while the fuel cut processing control means executes the fuel cut process during the execution of the filter regeneration process by the filter regeneration process control means, the EGR valve control means controls the EGR valve. The vehicle control system according to claim 1 or 2, wherein the fuel cut processing control means stops the fuel cut process after the fuel cut process is fully closed and a predetermined time has elapsed. With the internal combustion engine to which the intake and exhaust paths are connected,
A purification device installed in the exhaust path and having a filter for collecting particulate matter in the exhaust gas,
The EGR system is provided with an EGR passage that is connected to the downstream side of the exhaust path to the downstream side of the purification device and returns the exhaust gas to the intake path, and an EGR valve that adjusts the flow rate of the exhaust gas that returns to the intake path. It is a program to control the vehicle
A filter regeneration processing control means for controlling the filter regeneration processing for the filter,
A fuel cut processing control means for controlling a fuel cut process for cutting the fuel supply to the internal combustion engine, and a fuel cut process control means.
A computer is made to function as an EGR valve control means for controlling the opening and closing of the EGR valve.
When the fuel cut condition is satisfied during the execution of the filter regeneration process by the filter regeneration process control means, the fuel cut process control means fuels the EGR valve control means with the EGR valve set to a predetermined opening degree. A program characterized by executing a cut process.

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