This application is the U.S. National Phase under 35 U.S.C. § 371 of International Application No. PCT/JP2022/036442, filed on Sep. 29, 2022.
The invention relates to a vehicle control apparatus to be provided in a vehicle.
A vehicle including an engine as an internal combustion engine is provided with an air flow sensor such as a heat wire air flow sensor or a Karman vortex air flow sensor, as a flow sensor that detects an intake air flow rate (refer to Patent Literatures 1 to 5).
In the meanwhile, depending on an operating region of an engine, pulsation of intake air occurs in an intake passage, causing possibility of great fluctuation of an output signal of an air flow sensor. Such great fluctuation of the output signal of the air flow sensor is a factor of a decline in calculation accuracy of an intake air flow rate by a control system that receives the output signal. Moreover, the decline in the calculation accuracy of the intake air flow rate is a factor of a decline in control accuracy of an air-fuel ratio. Thus, what is desired is to enhance the calculation accuracy of the intake air flow rate.
An object of the invention is to enhance calculation accuracy of an intake air flow rate.
A vehicle control apparatus of an embodiment is a vehicle control apparatus to be provided in a vehicle. The vehicle control apparatus includes: an air flow sensor provided in an intake passage of an engine; and a control system including a processor and a memory communicatably coupled to each other. The control system is configured to read an output signal from the air flow sensor as first flow rate data. The control system is configured to calculate a coefficient of variation of the first flow rate data. The control system is configured to subject the first flow rate data to a smoothing process to calculate second flow rate data. The control system is configured to correct the second flow rate data based on the coefficient of variation to calculate corrected flow rate data. The corrected flow rate data indicates an intake air flow rate in the intake passage.
According to an aspect of the invention, the control system calculates the coefficient of variation of the first flow rate data. The control system subjects the first flow rate data to the smoothing process to calculate the second flow rate data. The control system corrects the second flow rate data based on the coefficient of variation to calculate the corrected flow rate data. The corrected flow rate data indicates the intake air flow rate in the intake passage. Hence, it is possible to enhance calculation accuracy of the intake air flow rate.
In the following, some embodiments of the invention are described in detail with reference to the drawings. Note that throughout the following description, the same or substantially the same configuration and element are denoted with the same reference numerals to avoid any redundant description.
[Vehicle]
[Engine]
The intake system 25 of the engine 12 includes an air cleaner box 31, a throttle valve 32, an intake manifold 33, a tumble generator valve 34, and intake pipes 35 and 36 coupling these components together. Moreover, the exhaust system 27 of the engine 12 includes an exhaust manifold 40, a catalytic converter 41, a silencer 42, and exhaust pipes 43 and 44 coupling these components together. The intake air taken into the air cleaner box 31 is supplied to the combustion chamber 28 through the throttle valve 32, the intake manifold 33, the tumble generator valve 34, and the intake port 24. Moreover, the exhaust gas discharged from the combustion chamber 28 is discharged to the outside through the exhaust manifold 40, the catalytic converter 41, and the silencer 42.
The intake port 24 of the intake system 25 is provided with a partition plate 45 that partitions an inside of the intake port 24 into two flow paths 24a and 24b. As illustrated in
The engine 12 is provided with an EGR device 50 that supplies a portion of the exhaust gas (hereinafter, referred to as an EGR gas) to the intake system 25 from the exhaust system 27. It is to be noted that EGR is “Exhaust Gas Recirculation”. The EGR device 50 includes an EGR upstream pipe 51, an EGR downstream pipe 52, and an EGR valve. The EGR upstream pipe 51 is coupled to the exhaust pipe 43 of the exhaust system 27. The EGR downstream pipe 52 is coupled to the intake manifold 33 of the intake system 25. The EGR valve 53 is provided between the EGR upstream pipe 51 and the EGR downstream pipe 52. Moreover, the EGR upstream pipe 51 is provided with an EGR cooler 54 that cools the EGR gas. When the EGR valve 53 is opened, the EGR gas is supplied to the intake system 25 from the exhaust system 27 through the EGR upstream pipe 51 and the EGR downstream pipe 52, as denoted by an arrow Ge. In the meanwhile, when the EGR valve 53 is closed, communication between the EGR upstream pipe 51 and the EGR downstream pipe 52 is shut off, resulting in a stop of the supply of the EGR gas to the intake system 25 from the exhaust system 27.
[Control System]
As sensors to be coupled to the electronic control unit 60, there are a vehicle speed sensor 70, an accelerator sensor 71, a brake sensor 72, and an engine speed sensor 73. The vehicle speed sensor 70 detects a vehicle speed. The accelerator sensor 71 detects an amount of operation of an accelerator pedal. The brake sensor 72 detects an amount of operation of a brake pedal. The engine speed sensor 73 detects an engine speed. Moreover, as the sensors to be coupled to the electronic control unit 60, there are an air flow sensor 74, a front A/F sensor 75, and a rear A/F sensor 76. The air flow sensor 74 is provided in the intake pipe (intake passage) 35 and detects the intake air flow rate. The front A/F sensor 75 is provided in the exhaust pipe 43 and detects an air-fuel ratio. The rear A/F sensor 76 is provided in the exhaust pipe 44 and detects the air-fuel ratio. Furthermore, a start switch 77 is coupled to the electronic control unit 60. The start switch 77 is operated by a driver at a start-up of the control system 61.
The control units 63 to 67 of the electronic control unit 60 set respective control targets of the throttle valve 32, the tumble generator valve 34, the EGR device 50, the injector 29, and the ignition device 30 based on output signals from the respective sensors. Moreover, the control units 63 to 67 of the electronic control unit 60 output control signals set in accordance with the respective control targets, to the throttle valve 32, the tumble generator valve 34, the EGR device 50, the injector 29, and the ignition device 30. For example, the electronic control unit 60 sets a target opening of the throttle valve 32 based on the engine speed and a requested driving force, and controls the throttle valve 32 toward the target opening. Moreover, the electronic control unit 60 calculates the intake air flow rate based on the output signal from the air flow sensor 74, and controls the amount of fuel injection of the injector 29 based on the intake air flow rate. That is, the electronic control unit 60 controls the amount of fuel injection of the injector 29 based on the calculated intake air flow rate, to converge an excess air ratio λ to a predetermined target value (for example, “1”).
It is to be noted that the excess air ratio λ is an index indicating a deviation from a stoichiometric air-fuel ratio, and is a value obtained by dividing the actual air-fuel ratio by the stoichiometric air-fuel ratio. That is, by controlling the excess air ratio λ to “1”, it is possible to obtain an air-fuel mixture of the stoichiometric air-fuel ratio, and enhance thermal efficiency of the engine 12. Moreover, an air-fuel mixture when the excess air ratio λ is greater than “1” is a lean air-fuel mixture in which fuel is thinner than the stoichiometric air-fuel ratio. An air-fuel mixture when the excess air ratio 2 is smaller than “1” is a rich air-fuel mixture in which the fuel is thicker than the stoichiometric air-fuel ratio.
Moreover, the electronic control unit 60 is provided with, for example, an input circuit 83, a drive circuit 84, a communication circuit 85, an external memory 86, and a power supply circuit 87. The input circuit 83 converts signals inputted from various sensors, into signals suppliable to the microcontroller 82. The drive circuit 84 generates drive signals for, for example, the throttle valve 32 and the injector 29 mentioned above, based on a signal outputted from the microcontroller 82. The communication circuit 85 converts the signal outputted from the microcontroller 82 into a communication signal directed to, for example, another electronic control unit. Moreover, the communication circuit 85 converts a communication signal received from, for example, another electronic control unit, into a signal suppliable to the microcontroller 82. Furthermore, the power supply circuit 87 supplies a stable power supply voltage to, for example, the microcontroller 82, the input circuit 83, the drive circuit 84, the communication circuit 85, and the external memory 86. In addition, programs, various kinds of data, and the like are held in the external memory 86 including, for example, a nonvolatile memory.
[Calculation Error of Intake Air Flow Rate]
When the tumble generator valve 34 is closed and the EGR valve 53 is greatly opened as denoted by the time t1 in
Here,
As illustrated in
[Data Correction Control]
As described, depending on an operating situation of the engine 12, the pulsation of the intake air occurs in the intake system 25, causing the great fluctuation of the first flow rate data QA00D. Moreover, when the first flow rate data QA00D greatly fluctuates, the intake air flow rate based on the second flow rate data QAR becomes smaller than an actual intake air flow rate. Accordingly, it is difficult to appropriately control the excess air ratio λ toward the target value. Thus, the control system 61 carries out a data correction control described below, to correct the second flow rate data QAR to enhance the calculation accuracy of the intake air flow rate.
In the following, description is given of a state of carrying out the data correction control by the control system 61.
As illustrated in
In step S13, a coefficient of correction k1 is calculated from the coefficient of variation CoV based on the following Expression (2). Next, the flow proceeds to step S14, and the first flow rate data QA00D is subjected to the smoothing process such as the moving average processes, to calculate the second flow rate data QAR from the first flow rate data QA00D. In subsequent step S15, as given in the following Expression (3), the second flow rate data QAR is multiplied by the coefficient of correction k1, to calculate corrected flow rate data C_QAR indicating the intake air flow rate. It is to be noted that constants a and b included in Expression (2) are constants set by experiment, simulation, or the like.
Here,
As described, the coefficient of variation CoV is calculated from the multiple pieces of the first flow rate data QA00D, and the second flow rate data QAR is corrected based on the coefficient of variation CoV. Thus, the corrected flow rate data C_QAR is calculated from the second flow rate data QAR. Moreover, for example, the amount of fuel injection of the injector 29 is controlled based on the intake air flow rate obtained from the corrected flow rate data C_QAR. Hence, it is possible to accurately calculate the intake air flow rate flowing through the intake system 25, and appropriately control, for example, the excess air ratio 2.
The invention is not limited to the forgoing embodiments, but it should be appreciated that various modifications may be made without departing from the subject matter of the invention. For example, in the forgoing description, the control system 61 includes the single electronic control unit 60, but this is non-limiting. The control system 61 may include multiple electronic control units. Moreover, the air flow sensor 74 in the figure is a hot wire air flow sensor, but this is non-limiting. The air flow sensor 74 may be, for example, a Karman vortex air flow sensor. Furthermore, the engine 12 in the figure is a gasoline engine using gasoline as fuel, but this is non-limiting. The engine 12 may be an engine such as a diesel engine using fuel other than gasoline.
In addition, the number of samples of the first flow rate data QA00D to be used in calculating the coefficient of variation CoV may be the preset number of samples, or may be the number of samples that varies with the situation. For example, in the situation that the first flow rate data QA00D and the second flow rate data QAR rapidly change, responsiveness of the coefficient of variation CoV may be enhanced by reducing the number of samples of the first flow rate data QA00D. Moreover, in the situation that the first flow rate data QA00D and the second flow rate data QAR gradually change, the calculation accuracy of the coefficient of variation CoV may be enhanced by increasing the number of samples of the first flow rate data QA00D.
Filing Document | Filing Date | Country | Kind |
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PCT/JP2022/036442 | 9/29/2022 | WO |
Publishing Document | Publishing Date | Country | Kind |
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WO2024/069852 | 4/4/2024 | WO | A |
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Entry |
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International Search Report issued in the International Application No. PCT/JP2022/036442 on Dec. 20, 2022, w/English Translation. |
Number | Date | Country | |
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20250012229 A1 | Jan 2025 | US |