WO2023243032A1

WO2023243032A1 - Internal combustion engine control device

Info

Publication number: WO2023243032A1
Application number: PCT/JP2022/024091
Authority: WO
Inventors: 直道山口; 裕貴中居; 猛江頭; 正裕豊原
Original assignee: 日立Astemo株式会社
Priority date: 2022-06-16
Filing date: 2022-06-16
Publication date: 2023-12-21

Abstract

The present disclosure provides an internal combustion engine control device capable of simultaneously improving the stability and response of the transient response of the ejection pressure of a high-pressure fuel pump relative to a pressure target value. An internal combustion engine control device (ECU 100) is provided with a feedback control unit 110, a flow amount limitation unit 120, and an energization start angle computation unit 130. The feedback control unit 110 uses a pressure detection value Pd by a pressure sensor of fuel ejected from a high-pressure fuel pump into a fuel injection device, and a pressure target value Pt of the ejection pressure of the high-pressure fuel pump as inputs, and outputs a pressure deviation ΔP between the pressure detection value Pd and the pressure target value Pt, and a flow amount target value QT of the ejection flow amount of the high-pressure fuel pump. The flow amount limitation unit 120 uses the pressure deviation ΔP and the flow amount target value QT as inputs, and outputs a limited flow amount value QL which is obtained by limiting the flow amount target value QT, on the basis of the value of the pressure deviation ΔP and an amount of change. The energization start angle computation unit 130 calculates an energization start phase θon in reciprocating movement of a plunger at which energization of an electromagnetic valve of the high-pressure fuel pump is started, in accordance with the limited flow amount value QL.

Description

Internal combustion engine control device

The present disclosure relates to a control device for an internal combustion engine.

Control devices for internal combustion engines have been known for some time. For example, the control device for an internal combustion engine described in Patent Document 1 below controls an internal combustion engine including an engine-driven high-pressure fuel pump that supplies high-pressure fuel from a fuel tank to a fuel injection means (Paragraph 0014, Claims 1). The high pressure fuel pump is driven by a cam of the internal combustion engine. By closing the on-off valve on the inlet side of the high-pressure fuel pump at a desired timing based on the angle of the shaft that drives the cam, a desired amount of high-pressure fuel is discharged.

This conventional control device includes means for detecting the rotation speed of the internal combustion engine, means for detecting the pressure of the high-pressure fuel, and a means for detecting the pressure of the high-pressure fuel so that the detected pressure of the high-pressure fuel becomes a target pressure. and control means for feedback controlling the high pressure fuel pump. This control means includes a means for calculating a deviation between the detected high pressure fuel pressure and a target pressure, a means for calculating a feedback operation amount based on the deviation, and a means for calculating a feedback operation amount based on the deviation. , calculation means for calculating the required discharge amount of the high-pressure fuel pump.

Furthermore, the control means includes means for calculating an angle of the shaft that satisfies the required discharge amount in consideration of the rotational speed of the internal combustion engine and the detected pressure of the high-pressure fuel, and the calculated angle. and means for controlling the opening/closing valve to close when the angle of the shaft is reached. The control device further includes means for detecting a sudden change in the target pressure, and holding means for holding the feedback control parameter so as not to change when the sudden change is detected.

This conventional internal combustion engine control device holds the integral term, which is a feedback control parameter, without updating it when the target pressure of high-pressure fuel changes suddenly. By doing this, it is possible to avoid a large integral term being integrated and a large integral term being calculated in a state where the deviation is large, and it is possible to avoid a large overshoot or a large undershoot (Patent Document 1, No. 0015 paragraph).

Japanese Patent Application Publication No. 2007-032322

In the conventional internal combustion engine control device described above, by holding the integral term of feedback control without updating, the discharge pressure of the high-pressure fuel pump is prevented from greatly overshooting the pressure target value, and the stability of the transient response is improved. can be improved. However, in this conventional internal combustion engine control device, there is a risk that the responsiveness of the discharge pressure of the high-pressure fuel pump to the pressure target value may be reduced.

The present disclosure provides a control device for an internal combustion engine that can simultaneously improve the stability and responsiveness of a transient response of the discharge pressure of a high-pressure fuel pump to a pressure target value.

One aspect of the present disclosure includes a pressurized chamber into which fuel is introduced from a fuel tank via a low-pressure fuel pump, an electromagnetic valve that opens and closes a flow path for introducing the fuel into the pressurized chamber, and a solenoid valve that opens and closes a flow path for introducing the fuel into the pressurized chamber. A control device for an internal combustion engine that controls the discharge pressure of the fuel discharged from a high-pressure fuel pump having a plunger that pressurizes the introduced fuel to a fuel injection device that injects the fuel into a combustion chamber of the internal combustion engine. The pressure detection value of the fuel discharged from the high-pressure fuel pump to the fuel injection device by the pressure sensor and the pressure target value of the discharge pressure are input, and the pressure detection value and the pressure target value are input. a feedback control unit that outputs a pressure deviation between the two and a flow rate target value of the discharge flow rate of the high-pressure fuel pump; , calculating a energization start phase in a reciprocating motion of a flow rate limiting section that outputs a restricted flow rate value that limits the flow rate target value, and the plunger that starts energizing the solenoid valve of the high-pressure fuel pump in accordance with the restricted flow rate value; 1. A control device for an internal combustion engine, comprising: an energization start angle calculation section.

According to the above aspect of the present disclosure, it is possible to provide a control device for an internal combustion engine that can simultaneously improve the stability and responsiveness of a transient response to a pressure target value of the discharge pressure of a high-pressure fuel pump.

1 is a block diagram showing an embodiment of a control device for an internal combustion engine according to the present disclosure. FIG. 2 is a block diagram showing a configuration example of a control device for the internal combustion engine shown in FIG. 1. FIG. FIG. 3 is a block diagram showing an example of a flow rate restriction section of the control device for the internal combustion engine shown in FIG. 2; FIG. 4 is a flow diagram showing the flow of processing by the flow rate restriction section of FIG. 3; 5 is a limit value map illustrating an example of a process for determining limit values in FIG. 4; 3 is a graph illustrating the action of the control device for the internal combustion engine shown in FIG. 2. FIG. FIG. 4 is a block diagram showing a modification of the flow rate restriction section of FIG. 3; FIG. 3 is a block diagram showing an example of an FDBK control section of the control device for the internal combustion engine shown in FIG. 2. FIG.

Hereinafter, embodiments of an internal combustion engine control device according to the present disclosure will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a control device for an internal combustion engine according to the present disclosure. The internal combustion engine control device of this embodiment is configured by, for example, an electronic control unit (ECU) 100 that is part of an engine system 1 installed in a vehicle. The engine system 1 includes, for example, an engine 2 that is an internal combustion engine, a fuel tank 3, a low-pressure fuel pump 4, a high-pressure fuel pump 5, a fuel injection device 6, an accelerator opening sensor 7, and an ECU 100. ing.

The engine 2 includes, for example, an intake pipe, a throttle body, a throttle valve, an intake manifold, an intake port, a cylinder, a spark plug, a piston, a crankshaft, a camshaft, an exhaust port, an exhaust pipe, etc., which are not shown. The engine 2 takes intake air into an intake pipe based on, for example, the operation of a piston. The flow rate of the intake air taken into the intake pipe is controlled by a throttle valve provided on the throttle body as it passes through the throttle body.

The intake air that has passed through the throttle body passes through the intake manifold, is further mixed with fuel injected from the injector 62 provided in the intake port, and is guided to the combustion chamber of the cylinder in the form of an air-fuel mixture. A spark plug uses spark ignition to explosively combust an air-fuel mixture in a combustion chamber to generate mechanical energy, which rotates a crankshaft and a camshaft connected to a piston. Gas generated by combustion is discharged from the combustion chamber of the cylinder to the exhaust pipe through the exhaust port, and is discharged outside the vehicle from the exhaust pipe as exhaust gas.

The fuel tank 3 stores liquid fuel such as gasoline, diesel oil, or ethanol. The low-pressure fuel pump 4 is provided, for example, in the middle of a fuel supply pipe 8 that connects the fuel tank 3 and the high-pressure fuel pump 5, and pumps fuel from the fuel tank 3 to the high-pressure fuel pump 5 through the fuel supply pipe 8. The high-pressure fuel pump 5 , for example, pressurizes the fuel supplied via the fuel supply pipe 8 and discharges it to the common rail 61 of the fuel injection device 6 .

Note that the fuel discharge pressure of the low-pressure fuel pump 4 is lower than the fuel discharge pressure of the high-pressure fuel pump 5, and the fuel discharge pressure of the high-pressure fuel pump 5 is lower than the fuel discharge pressure of the low-pressure fuel pump 4. High pressure. That is, "low pressure" and "high pressure" in the low-pressure fuel pump 4 and high-pressure fuel pump 5 represent the relative relationship between the discharge pressures of the respective fuel pumps, and do not define specific pressure ranges. do not have.

The high-pressure fuel pump 5 includes, for example, an inlet 51, a solenoid valve 52, a pressurizing chamber 53, a plunger 54, a discharge valve 55, and a discharge port 56. The suction port 51 is connected to, for example, the fuel supply pipe 8, and fuel pumped by the low-pressure fuel pump 4 is introduced into the suction port 51. The solenoid valve 52 is provided, for example, in the middle of a flow path 57 that supplies fuel from the inlet 51 to the pressurizing chamber 53, and is controlled to open and close by the ECU 100, and opens and closes the flow path 57 that supplies fuel to the pressurizing chamber 53. do.

Fuel is introduced into the pressurizing chamber 53 from the fuel tank 3 via the low-pressure fuel pump 4. More specifically, fuel is introduced from the fuel tank 3 to the suction port 51 via the low-pressure fuel pump 4, and the flow path 57 is opened and closed between the suction port 51 and the pressurizing chamber 53. It passes through the electromagnetic valve 52 and is introduced into the pressurizing chamber 53. The high-pressure fuel pump 5 may include, for example, a pulsation reducing section 58 that reduces pressure pulsations in the fuel sucked through the suction port 51 and discharged from the discharge port 56.

The plunger 54 pressurizes the fuel introduced into the pressurizing chamber 53. The plunger 54 is housed in a cylinder 59, for example, and defines a pressurizing chamber 53 together with the cylinder 59. The plunger 54 is provided so as to be able to reciprocate in the axial direction by a drive mechanism (not shown). The drive mechanism reciprocates the plunger 54 in the axial direction by, for example, rotating a cam attached to the camshaft of the engine 2.

The phase of the reciprocating motion of the plunger 54 is detected, for example, by a cam angle sensor that detects the rotation angle of the camshaft, and is input to the ECU 100. That is, the cam angle sensor functions, for example, as an angle sensor that detects the phase of the plunger 54 of the high-pressure fuel pump 5, and the detected phase value θd of the reciprocating motion of the plunger 54 is dependent on the cam angle λcam detected by the cam angle sensor. It can be calculated based on

The discharge valve 55 is provided between the pressurizing chamber 53 and the discharge port 56. When there is no pressure difference between the fuel inside the pressurizing chamber 53 and the fuel on the downstream side of the discharge valve 55, the valve body of the discharge valve 55 contacts the seat surface of the seat member and closes due to the biasing force of the spring. It is in a valve state. When the pressure of the fuel inside the pressurizing chamber 53 becomes greater than the pressure of the fuel on the downstream side of the discharge valve 55, and the differential pressure exceeds the biasing force of the spring, the valve body separates from the seating surface of the seat member. The valve becomes open. The discharge port 56 is connected, for example, to the common rail 61 of the fuel injection device 6 and discharges high-pressure fuel pressurized in the pressurizing chamber 53 to the common rail 61.

The fuel injection device 6 includes, for example, a common rail 61, an injector 62, and a pressure sensor 63. The common rail 61 stores high-pressure fuel supplied from the high-pressure fuel pump 5 and distributes the high-pressure fuel to the plurality of injectors 62. Each injector 62 injects high-pressure fuel supplied via the common rail 61 into the cylinder of the engine 2, for example. The pressure sensor 63 detects the pressure of high-pressure fuel discharged from the high-pressure fuel pump 5 to the common rail 61, and outputs the pressure detection result to the ECU 100 via a signal line.

The accelerator opening sensor 7 is connected to the ECU 100 via a signal line, for example, and detects the amount of depression of the accelerator pedal by the driver of the vehicle as the accelerator opening, and outputs the detected accelerator opening to the ECU 100. ECU 100 is configured by, for example, one or more microcontrollers, and is connected to low pressure fuel pump 4, high pressure fuel pump 5, and fuel injection device 6 via signal lines, and is connected to low pressure fuel pump 4, high pressure fuel pump 5, and fuel injection device 6 through signal lines. and controls the fuel injection device 6.

FIG. 2 is a block diagram showing a configuration example of the ECU 100 in FIG. 1. The ECU 100, which is the control device for the internal combustion engine of this embodiment, controls the discharge pressure of fuel discharged from the high-pressure fuel pump 5 to the fuel injection device 6 that injects fuel into the combustion chamber of the engine 2. ECU 100 includes, for example, a feedback (FDBK) control section 110, a flow rate restriction section 120, and an energization start angle calculation section 130. Further, the ECU 100 includes, for example, an energization start angle limiting section 140, an energization end angle calculation section 150, an energization end angle limiting section 160, and a solenoid valve control section 170.

Each part of the ECU 100 shown in FIG. 2 represents each function of the internal combustion engine control device of this embodiment, which is realized by, for example, executing a program stored in a storage device such as a memory by a central processing unit (CPU). ing. Note that each part of the ECU 100 shown in FIG. 2 may be configured, for example, by one or more devices, or by one device.

The feedback control unit 110 receives, for example, a pressure detection value Pd of the fuel discharged from the high-pressure fuel pump 5 to the fuel injection device 6 by the pressure sensor 63 and a pressure target value Pt of the discharge pressure of the high-pressure fuel pump 5. . For example, the ECU 100 inputs a pressure target value Pt of the discharge pressure of the high-pressure fuel pump 5 calculated based on the detected value of the accelerator opening sensor 7 to the feedback control unit 110.

For example, the feedback control unit 110 controls the pressure deviation ΔP between the pressure detection value Pd and the pressure target value Pt and the discharge flow rate of the high-pressure fuel pump 5 based on the input pressure detection value Pd and pressure target value Pt. The target flow rate value QT is output. More specifically, the feedback control unit 110 calculates a flow rate target value QT as a required discharge amount of the high-pressure fuel pump 5 necessary to match the detected pressure value Pd and the pressure target value Pt.

FIG. 3 is a block diagram showing an example of the flow rate restriction section 120 of the ECU 100 in FIG. 2. The flow rate restriction unit 120 receives the pressure deviation ΔP and the flow rate target value QT, and outputs a restricted flow rate value QL that limits the flow rate target value QT based on the value of the pressure deviation ΔP and the amount of change dΔP. The flow rate restriction unit 120 includes, for example, a change amount calculation unit 121, a limit value determination unit 122, a restriction flow value calculation unit 123, and a restriction processing unit 124.

FIG. 4 is a flowchart showing the flow of processing by the energization start angle calculation unit 130 of FIG. 3. When the flow rate restriction unit 120 starts the process flow shown in FIG. 4, it first starts a process S1 for calculating the amount of change dΔP in the pressure deviation ΔP. In this process S1, the change amount calculation unit 121 calculates the change amount dΔP of the pressure deviation ΔP based on the pressure deviation ΔP input from the feedback control unit 110, for example.

Here, the amount of change dΔP in the pressure deviation ΔP is an increase or decrease in the pressure deviation ΔP per unit time, that is, the rate of change in the pressure deviation ΔP. More specifically, the change amount calculation unit 121 calculates, for example, by dividing the difference between the pressure deviation ΔP obtained in the previous process and the pressure deviation ΔP obtained in the current process by the process cycle. Calculate the amount of change dΔP in the pressure deviation ΔP.

Next, the flow rate restriction unit 120 executes a process S2 to determine the limit value LV. In this process S2, the limit value determining unit 122 determines a larger limit value LV as the value of the pressure deviation ΔP decreases and as the amount of change dΔP of the pressure deviation ΔP increases. More specifically, the limit value determining unit 122 uses a limit value map stored in a storage device such as a memory included in the ECU 100 to determine the limit value LV based on the value of the pressure deviation ΔP and the amount of change dΔP thereof. Determine.

FIG. 5 is a graph showing an example of a limit value map used in the process S2 of determining the limit value LV in FIG. In FIG. 5, the limit value LV(H) indicated by a dark circle is larger than the limit value LV(L) indicated by a light circle. The limit value map is, for example, a graph in which the horizontal axis is the pressure deviation ΔP [%] and the vertical axis is the amount of change dΔP [%/s]. It is specified that as the amount dΔP increases, a larger limit value LV(H) is selected.

In the example shown in FIG. 5, two different limit values LV, a relatively large limit value LV (H) and a small limit value LV (L), are defined, but there are three or more different limit values LV. A limit value LV may be defined. In the example shown in FIG. 5, until the detected pressure value Pd reaches 63.2% of the target pressure value Pt, that is, the pressure deviation ΔP between the target pressure value Pt and the detected pressure value Pd is 36.8%. ] The limit value LV is not set until it is below. The limit value determination unit 122 refers to such a limit value map and determines the limit value LV based on the value of the pressure deviation ΔP and the amount of change dΔP in the pressure deviation ΔP.

Next, the flow rate restriction unit 120 executes a process S3 of calculating a restricted flow rate value QL. In this process S3, the restricted flow rate value calculation unit 123 calculates the restricted flow rate value QL by subtracting the restricted value LV from the upper limit discharge flow rate Qmax based on the static characteristics of the high-pressure fuel pump 5, for example. The upper limit discharge flow rate Qmax based on the static characteristics of the high-pressure fuel pump 5 is inputted from the energization start angle calculation unit 130 to the flow rate restriction unit 120, as shown in FIG. 2, for example.

Next, the flow rate restriction unit 120 executes a flow rate restriction process S4 that limits the flow rate target value QT by the restricted flow rate value QL. In this process S4, as shown in FIG. do. For example, the restriction processing unit 124 outputs the target flow value QT when the target flow value QT does not exceed the restricted flow value QL, and outputs the restricted flow value QL when the target flow value QT exceeds the restricted flow value QL. do.

As a result, the output of the flow rate restriction section 120 is limited to a value equal to or less than the limit flow rate value QL obtained by subtracting the limit value LV from the upper limit discharge flow rate Qmax. With the above, the processing flow of the flow rate restriction section 120 shown in FIG. 4 is completed.

For example, as shown in FIG. 2, the energization start angle calculation section 130 receives as input the rotational speed Re of the engine 2, the battery voltage Vb, and the restricted flow rate value QL or the flow rate target value QT output from the flow rate restriction section 120. do. The energization start angle calculation unit 130 calculates, for example, the energization start phase θon in the reciprocating motion of the plunger 54 that starts energizing the solenoid valve 52 of the high-pressure fuel pump 5 according to the input limited flow value QL or flow rate target value QT. do.

Further, the energization start angle calculation unit 130 determines the upper limit discharge flow rate Qmax of the high-pressure fuel pump 5 by referring to a static characteristic map of the high-pressure fuel pump 5 stored in a storage device such as a memory of the ECU 100. Output to. More specifically, the energization start angle calculation unit 130 refers to a static characteristic map of the high-pressure fuel pump 5 according to the rotational speed Re of the engine 2 and the voltage Vb of the battery, for example.

The static characteristic map of the high-pressure fuel pump 5 is, for example, a graph in which the horizontal axis represents the energization start phase θon [deg] and the vertical axis represents the discharge flow rate Q [mg/stroke] of the high-pressure fuel pump 5. The energization start angle calculation unit 130 outputs the energization start phase θon corresponding to the inputted flow rate limit value QL or target flow rate QT, for example, based on the static characteristic map of the high-pressure fuel pump 5.

The energization start angle limiting section 140 receives the energization start phase θon output from the energization start angle calculation section 130 as input. The energization start angle limiting section 140 outputs the energization start phase θLon, which is obtained by limiting the input energization start phase θon by the phase of the bottom dead center (BDC) and the phase of the top dead center (TDC) of the plunger 54.

The energization end angle calculation unit 150 receives, for example, the crank angle φcra and cam angle λcam detected by a crank angle sensor and a cam angle sensor that detect the rotation angles of the crankshaft and camshaft of the engine 2. The energization end angle calculation unit 150 outputs the energization end phase θoff of the electromagnetic valve 52 of the high-pressure fuel pump 5 based on the crank angle φcra and the cam angle λcam.

The energization end angle limiting section 160 receives the energization end phase θoff output from the energization end angle calculation section 150 as input. The energization end angle limiting section 160 outputs the energization end phase θLoff, which is obtained by limiting the input energization end phase θoff by the BDC phase and the TDC phase of the plunger 54.

The solenoid valve control unit 170 generates a drive pulse DP for driving the solenoid of the solenoid valve 52 of the high-pressure fuel pump 5 based on the input energization start phase θLon and the energization end phase θLoff. Output to valve 52. More specifically, the electromagnetic valve control unit 170 receives, for example, a phase detection value θd by an angle sensor that detects the phase of the plunger 54, an energization start phase θLon, and an energization end phase θLoff.

For example, when the phase detection value θd becomes equal to the energization start phase θLon, the solenoid valve control unit 170 starts energizing the solenoid valve 52 and opens the flow path 57. Further, the solenoid valve control unit 170 ends the energization of the solenoid valve 52 and closes the flow path 57, for example, when the phase detection value θd becomes equal to the energization end phase θLoff. As a result, fuel is supplied to the pressurizing chamber 53 of the high-pressure fuel pump 5 at a flow rate corresponding to the restricted flow rate value QL or the target flow rate QT output from the flow rate restricting section 120, and from the high-pressure fuel pump 5 to the fuel injection device 6. It is discharged.

FIG. 6 is a graph illustrating the operation of the internal combustion engine control device of this embodiment shown in FIG. 2. Hereinafter, the operation of the internal combustion engine control device according to the present embodiment will be explained based on comparison with an internal combustion engine control device according to a comparative example.

The upper left graph in FIG. 6 is a graph showing temporal changes in the pressure target value Pt and pressure detection value Pd of the high-pressure fuel pump 5 controlled by the internal combustion engine control device according to the comparative example. The lower left graph in FIG. 6 is a graph showing temporal changes in the flow rate target value QT of the high-pressure fuel pump 5 controlled by the internal combustion engine control device according to the comparative example and the actual discharge flow rate Qd detected by the flow rate sensor.

The internal combustion engine control device according to the comparative example differs from the ECU 100, which is the internal combustion engine control device according to the present embodiment, in that it does not have the flow rate restriction section 120 shown in FIG. The other configurations of the internal combustion engine control device according to the comparative example are the same as the internal combustion engine control device according to the present embodiment. In the internal combustion engine control device according to the comparative example, the feedback control unit 110 performs feedback control of the discharge pressure of the high-pressure fuel pump 5, that is, the detected pressure value Pd.

For example, assume a case where the accelerator opening, which is the detected value of the accelerator opening sensor 7, rapidly increases when a vehicle equipped with the engine system 1 suddenly starts. In this case, in the internal combustion engine control device of the comparative example, a step-like pressure target value Pt as shown in the upper left graph of FIG. 6 is input to the feedback control unit 110. As a result, as shown in the lower left graph of FIG. 6, the flow rate target value QT output from the feedback control unit 110 increases rapidly, and for example, the flow rate target value QT is limited to the upper limit discharge flow rate Qmax by the energization start angle calculation unit 130. Ru.

However, in the internal combustion engine control device according to the comparative example that does not include the flow rate restriction section 120, the discharge flow rate Qd of fuel from the high-pressure fuel pump 5 increases to exceed the target flow rate value QT. As a result, in the control device for an internal combustion engine according to the comparative example, the detected pressure value Pd, which is the discharge pressure of the high-pressure fuel pump 5, rapidly increases and an overshoot occurs that greatly exceeds the pressure target value Pt. Pulsations occur in the discharge pressure.

That is, in the control device for an internal combustion engine according to the comparative example that does not include the flow rate restricting section 120, there is a problem that the stability of the transient response of the fuel discharge pressure of the high-pressure fuel pump 5 to the pressure target value Pt decreases. In the internal combustion engine control device of such a comparative example, when the overshoot of the discharge pressure of the high-pressure fuel pump 5 is suppressed by gain adjustment of the feedback control unit 110, the discharge pressure of the high-pressure fuel pump 5 with respect to the pressure target value Pt is Responsiveness may decrease.

On the other hand, the ECU 100 that constitutes the control device for the internal combustion engine of this embodiment controls the discharge pressure of the fuel discharged from the high-pressure fuel pump 5 to the fuel injection device 6. As described above, the high-pressure fuel pump 5 includes a pressurizing chamber 53 into which fuel is introduced from the fuel tank 3 via the low-pressure fuel pump 4, and an electromagnetic electromagnetic device that opens and closes a flow path 57 through which fuel is introduced into the pressurizing chamber 53. It has a valve 52 and a plunger 54 that pressurizes the fuel introduced into the pressurizing chamber 53. As described above, the fuel injection device 6 injects fuel into the combustion chamber of the engine 2, which is an internal combustion engine. As described above, the ECU 100 includes the feedback control section 110, the flow rate restriction section 120, and the energization start angle calculation section 130. A pressure detection value Pd of the fuel discharged from the high-pressure fuel pump 5 to the fuel injection device 6 by the pressure sensor 63 and a pressure target value Pt of the discharge pressure of the high-pressure fuel pump 5 are input to the feedback control unit 110 . The feedback control unit 110 also controls the pressure deviation ΔP between the pressure detection value Pd and the pressure target value Pt and the discharge flow rate of the high-pressure fuel pump 5 based on the input pressure target value Pt and pressure detection value Pd. The target flow rate value QT is output. The flow rate restriction unit 120 receives the pressure deviation ΔP and the flow rate target value QT, and outputs a restricted flow rate value QL that limits the flow rate target value QT based on the value of the pressure deviation ΔP and the amount of change dΔP. The energization start angle calculation unit 130 calculates the energization start phase θon in the reciprocating motion of the plunger 54 that starts energizing the electromagnetic valve 52 of the high-pressure fuel pump 5 in accordance with the restricted flow rate value QL.

With such a configuration, the internal combustion engine control device of the present embodiment inputs a step-like pressure target value Pt as shown in the upper right graph of FIG. Then, it works as follows. As shown in the lower right graph of FIG. 6, the flow rate target value QT output from the feedback control unit 110 increases rapidly, and, for example, the flow rate target value QT is adjusted to the static characteristics of the high-pressure fuel pump 5 by the energization start angle calculation unit 130. is limited to the upper limit discharge flow rate Qmax.

Furthermore, due to the rapid increase in the target flow rate QT of the discharge flow rate of the high-pressure fuel pump 5, the pressure detection value Pd of the fuel discharged from the high-pressure fuel pump 5 to the fuel injection device 6 by the pressure sensor 63 rapidly increases. Then, the pressure deviation ΔP between the pressure target value Pt and the pressure detection value Pd decreases, and for example, the pressure detection value Pd decreases until the pressure detection value Pd reaches about 62.3% of the pressure target value Pt. The amount of change dΔP increases.

Here, as described above, the control device for an internal combustion engine of this embodiment includes a flow rate limiting section 120 that outputs a restricted flow rate value QL that limits the flow rate target value QT based on the value of the pressure deviation ΔP and the amount of change dΔP. have. Therefore, as shown in the upper right and lower right graphs of FIG. 6, before the detected pressure value Pd exceeds the pressure target value Pt, the flow rate limiter 120 limits the flow rate target value QT to the lower restricted flow rate value QL1. .

As a result, the energization start angle calculation unit 130 determines the energization start phase θon in the reciprocating motion of the plunger 54 that starts energizing the solenoid valve 52 of the high-pressure fuel pump 5 in accordance with the restricted flow rate value QL1 output from the flow rate restriction unit 120. calculate. As a result, the increase in the discharge flow rate Qd of the high-pressure fuel pump 5 is restricted, and the amount of change in the pressure deviation ΔP between the pressure detection value Pd and the pressure target value Pt of the fuel discharged from the high-pressure fuel pump 5 to the fuel injection device 6 dΔP decreases. As a result, the discharge flow rate Qd of the high-pressure fuel pump 5 is prevented from exceeding the flow rate target value QT, and the detected pressure value Pd of the fuel discharged from the high-pressure fuel pump 5 to the fuel injection device 6 is prevented from exceeding the pressure target value Pt. Shoots are prevented.

Furthermore, the flow rate restriction unit 120 limits the flow rate target value QT to a limit flow rate value QL2 that is larger than the limit flow rate value QL1 and smaller than the flow rate target value QT, based on the amount of change dΔP of the reduced pressure deviation ΔP. This prevents an excessive decrease in the discharge flow rate Qd of the high-pressure fuel pump 5, and improves the responsiveness of the detected pressure value Pd of the fuel discharged from the high-pressure fuel pump 5 to the fuel injection device 6 with respect to the target pressure value Pt.

More specifically, in the internal combustion engine control device of this embodiment, the flow rate restriction section 120 includes a restriction value determination section 122, a restriction flow value calculation section 123, and a restriction processing section 124. The limit value determining unit 122 determines a larger limit value LV as the value of the pressure deviation ΔP decreases and as the amount of change dΔP of the pressure deviation ΔP increases. The restricted flow rate value calculation unit 123 subtracts the restricted value LV from the upper limit discharge flow rate Qmax based on the static characteristics of the high-pressure fuel pump 5 to calculate the restricted flow rate value QL. The restriction processing unit 124 outputs the target flow value QT if the target flow value QT does not exceed the restricted flow value QL, and outputs the restricted flow value QL if the target flow value QT exceeds the restricted flow value QL.

With such a configuration, the internal combustion engine control device of the present embodiment controls the discharge of the high-pressure fuel pump 5 when the step-like pressure target value Pt is input to the feedback control unit 110 as shown in the upper right graph of FIG. The detected pressure value Pd, which is the pressure, increases rapidly. As a result, when the pressure deviation ΔP between the pressure target value Pt and the detected pressure value Pd decreases and the amount of change dΔP in the pressure deviation ΔP increases, a relatively large limit value LV is determined.

As a result, the target flow rate QT is limited to a relatively small flow rate limit value QL1 obtained by subtracting the relatively large limit value LV from the upper limit discharge flow rate Qmax. Therefore, according to the control device for an internal combustion engine of this embodiment, it is possible to prevent the detected pressure value Pd from overshooting beyond the pressure target value Pt, and to prevent the discharge pressure of the high-pressure fuel pump 5 from overshooting with respect to the pressure target value Pt. Response stability can be improved.

Thereafter, the amount of change dΔP in the pressure deviation ΔP decreases, so that a relatively small limit value LV is determined. As a result, as shown in the lower right graph of FIG. 6, the target flow rate QT is limited to a relatively large restricted flow rate value QL2 obtained by subtracting the relatively small limit value LV from the upper limit discharge flow rate Qmax. Therefore, according to the control device for an internal combustion engine of the present embodiment, an excessive decrease in the discharge flow rate Qd of the high-pressure fuel pump 5 is prevented, and the pressure detection value Pd of the fuel discharged from the high-pressure fuel pump 5 to the fuel injection device 6 is prevented. The responsiveness of the transient response to the pressure target value Pt can be improved.

Furthermore, the internal combustion engine control device of this embodiment further includes a solenoid valve control section 170 shown in FIG. 2. The electromagnetic valve control unit 170 receives as input a phase detection value θd by an angle sensor that detects the phase of the plunger 54 of the high-pressure fuel pump 5 and an energization start phase θLon. The solenoid valve control unit 170 starts energizing the solenoid valve 52 and opens the flow path 57 when the detected phase value θd becomes equal to the energization start phase θLon.

With such a configuration, the solenoid of the solenoid valve 52 of the high-pressure fuel pump 5 starts to be energized and the flow path 57 is opened at the timing when the phase of the reciprocating motion of the plunger 54 becomes equal to the energization start phase θLon. As a result, fuel is introduced from the fuel tank 3 through the low-pressure fuel pump 4 into the pressurizing chamber 53 of the high-pressure fuel pump 5, is pressurized in the pressurizing chamber 53 of the high-pressure fuel pump 5, and is injected from the high-pressure fuel pump 5. Fuel is discharged to the device 6 at a flow rate corresponding to the restricted flow rate value QL or the target flow rate value QT.

As described above, the present embodiment provides a control device for an internal combustion engine that can simultaneously improve the stability and responsiveness of the transient response to the pressure target value Pt of the discharge pressure of the high-pressure fuel pump 5. be able to. Note that the internal combustion engine control device of this embodiment is not limited to the above-described embodiment. Hereinafter, some modifications of the above-described embodiment will be described with reference to FIGS. 7 and 8.

FIG. 7 is a block diagram showing a modification of the flow rate restriction section 120 of FIG. 3. For example, the flow rate restriction section 120 may not include the restricted flow rate value calculation section 123 shown in FIG. 3 . In the modification of the internal combustion engine control device shown in FIG. 7, the flow rate restriction section 120 includes a change amount calculation section 121, a limit value determination section 122, and a restriction processing section 124. The change amount calculation unit 121 receives the pressure deviation ΔP and calculates the change amount dΔP of the pressure deviation ΔP, as in the above-described embodiment. Similarly to the embodiment described above, the limit value determining unit 122 determines a larger limit value LV as the value of the pressure deviation ΔP decreases and as the amount of change dΔP of the pressure deviation ΔP increases. Then, the restriction processing unit 124 calculates a restricted flow rate value QL by subtracting the restricted value LV from the target flow value QT.

The internal combustion engine control device according to this modification can also achieve the same effects as the internal combustion engine control device according to the above-described embodiment. Therefore, also in this modification, it is possible to provide a control device for an internal combustion engine that can simultaneously improve the stability and responsiveness of the transient response of the discharge pressure of the high-pressure fuel pump 5 to the pressure target value Pt.

In the internal combustion engine control device according to the embodiment and modification described above, the flow rate restriction unit 120 sets the value of the flow rate target value QT to the upper limit discharge flow rate Qmax or the limit flow rate obtained by subtracting the limit value LV from the flow rate target value QT. It was limited to the value QL. However, the internal combustion engine control device according to the present disclosure can also limit the flow rate target value QT using other methods.

For example, in the example shown in FIG. 7, the flow rate limiter 120 includes a limit value determiner 122 that determines the limit value LV based on the value of the pressure deviation ΔP and the amount of change dΔP, and a limit value determiner 122 that determines the limit value LV based on the value of the pressure deviation ΔP and the amount of change dΔP, and the amount of change in the target flow rate QT that determines the limit value. It may also include a restriction processing unit 124 that outputs a restricted flow rate value QL restricted by LV. That is, the limit value LV is a value for limiting the amount of change in the flow target value QT, which is the difference between the previous value and the current value of the flow target value QT.

According to the internal combustion engine control device according to this modification, not only can the same effects as the internal combustion engine control device according to the above-described embodiment be achieved, but also the high-pressure fuel pump 5 and fuel having large individual differences in static characteristics can be used. Compatible with the injection device 6. That is, when there are large individual differences in the static characteristics of the high-pressure fuel pump 5 and the fuel injection device 6, the flow target It is more effective to limit the amount of change in the value QT.

FIG. 8 is a block diagram showing an example of the feedback control section 110 of the internal combustion engine control device shown in FIG. 2. In the example shown in FIG. 8, the feedback control section 110 includes a pressure deviation calculation section 111, a proportional term calculation section 112, an integral term calculation section 113, and an addition section 114. The pressure deviation calculation unit 111 receives the pressure target value Pt and the detected pressure value Pd and calculates the pressure deviation ΔP. The proportional term calculation unit 112 calculates a proportional term based on the pressure deviation ΔP. The integral term calculation unit 113 calculates an integral term based on the pressure deviation ΔP. The adding unit 114 adds the proportional term and the integral term to calculate the flow rate target value QT. For example, when the flow rate target value QT is limited by the restricted flow rate value QL, the integral term calculation unit 113 receives the restriction determination LD from the flow rate restriction unit 120 as shown in FIGS. 2 and 8. The integral term calculation unit 113 stops calculating the integral term when the target flow rate QT is restricted by the restricted flow rate value QL, that is, when the restriction determination LD is input.

In this way, when the target flow rate QT is limited by the restricted flow rate value QL, the feedback control unit 110 stops the calculation of the integral term by the integral term calculation unit 113, thereby overcorrecting the target flow rate QT. In other words, it is possible to prevent the accumulation of integral quantities. Therefore, it becomes possible to more effectively prevent the detected pressure value Pd of the discharge pressure from the high-pressure fuel pump 5 from overshooting beyond the pressure target value Pt. Note that the calculation of the integral term can be stopped by, for example, holding the calculated value, setting the calculated value to zero, or subtracting the overcorrection at the time of limiting the flow rate target value QT from the integral term calculation value. It can be carried out.

Although the embodiments of the present disclosure and their modifications have been described above in detail using the drawings, the specific configurations are not limited to these embodiments and modifications, and within the scope of the gist of the present invention. Even if there are design changes, etc., they are included in the present disclosure.

2 Engine (internal combustion engine)
3 Fuel tank 4 Low pressure fuel pump 5 High pressure fuel pump 52 Solenoid valve 53 Pressurizing chamber 54 Plunger 57 Flow path 6 Fuel injection device 63 Pressure sensor 100 ECU (internal combustion engine control device)
110 Feedback control section 111 Pressure deviation calculation section 112 Proportional term calculation section 113 Integral term calculation section 114 Addition section 120 Flow rate restriction section 122 Limit value determination section 123 Restriction flow value calculation section 124 Restriction processing section 130 Energization start angle calculation section 170 Solenoid valve Control part dΔP Change amount of pressure deviation LV Limit value Pd Pressure detection value Pt Pressure target value QL Limit flow value Qmax Upper limit discharge flow rate QT Flow rate target value ΔP Pressure deviation θon Current supply start phase

Claims

A pressurizing chamber into which fuel is introduced from a fuel tank via a low-pressure fuel pump, an electromagnetic valve that opens and closes a flow path for introducing the fuel into the pressurizing chamber, and a solenoid valve that presses the fuel introduced into the pressurizing chamber. A control device for an internal combustion engine that controls the discharge pressure of the fuel discharged from a high-pressure fuel pump having a plunger that presses the fuel to a fuel injection device that injects the fuel into a combustion chamber of the internal combustion engine,
The pressure detected by the pressure sensor of the fuel discharged from the high-pressure fuel pump to the fuel injection device and the pressure target value of the discharge pressure are input, and the pressure between the pressure detected value and the pressure target value is input. a feedback control unit that outputs the deviation and a target flow rate value of the discharge flow rate of the high-pressure fuel pump;
a flow rate limiting section that receives the pressure deviation and the flow rate target value as input, and outputs a restricted flow rate value that limits the flow rate target value based on the value and the amount of change of the pressure deviation;
an energization start angle calculation unit that calculates an energization start phase in a reciprocating motion of the plunger that starts energization of the solenoid valve of the high-pressure fuel pump according to the restricted flow rate value;
A control device for an internal combustion engine, comprising:
The flow rate limiting unit includes a limit value determining unit that determines a larger limit value as the value of the pressure deviation decreases and the amount of change in the pressure deviation increases; The control device for an internal combustion engine according to claim 1, further comprising a restriction processing unit that calculates the restriction flow value by subtracting the restriction flow value.
The flow rate limiting section includes a limit value determining section that determines a larger limit value as the value of the pressure deviation decreases and as the amount of change in the pressure deviation increases; a limit flow rate value calculation unit that calculates the limit flow value by subtracting the limit value from the upper limit discharge flow rate, and outputs the target flow rate when the target flow rate value does not exceed the limit flow rate value; The control device for an internal combustion engine according to claim 1, further comprising a restriction processing section that outputs the restriction flow rate value when the target value exceeds the restriction flow rate value.
The flow rate limiter includes a limit value determining unit that determines a limit value based on the value of the pressure deviation and the amount of change, and outputs the limit flow value in which the amount of change in the target flow rate is limited by the limit value. The control device for an internal combustion engine according to claim 1, further comprising a restriction processing section that performs the following steps.
The feedback control section includes a pressure deviation calculation section that calculates the pressure deviation, a proportional term calculation section that calculates a proportional term based on the pressure deviation, and an integral term calculation section that calculates an integral term based on the pressure deviation. and an addition unit that calculates the flow rate target value by adding the proportional term and the integral term,
2. The control device for an internal combustion engine according to claim 1, wherein the integral term calculating section stops calculating the integral term when the target flow rate value is limited by the restricted flow rate value.
A phase detection value by an angle sensor that detects the phase of the plunger and the energization start phase are input, and when the phase detection value becomes equal to the energization start phase, energization to the solenoid valve is started to control the flow. 2. The control device for an internal combustion engine according to claim 1, further comprising a solenoid valve control section for opening the passage.