JP2021110324A - On-vehicle engine control device - Google Patents

Abstract

To provide an on-vehicle engine control device capable of suppressing enriching of an air-fuel ratio in restarting injection after fuel cut, and suppressing degradation of exhaust emission and acceleration traveling performance immediately after restarting the injection.SOLUTION: An ECU 70 as an on-vehicle engine control device, includes a fuel cut control portion 71, an opening control portion 72, and a cylinder reduction control portion 73. The fuel cut control portion 71 executes fuel cut, and the opening control portion 72 controls an opening (opening in cutting) of a throttle valve 60 in fuel cut. The cylinder reduction control portion 73 executes cylinder reduction control to reduce a fuel injection object to a part of a plurality of cylinders when fuel cut is terminated and fuel injection is restarted. The cylinder reduction control portion 73 executes cylinder reduction control under a condition that a supply fuel pressure (fuel pressure in cutting) in fuel cut is a prescribed pressure or more (high pressure standby state). The opening control portion 72 increases the opening in cutting in comparison with a case in a low pressure standby state, in the high pressure standby state.SELECTED DRAWING: Figure 1

Description

The disclosure in this specification relates to an in-vehicle engine control device applied to an engine system mounted on a vehicle.

Patent Document 1 describes a control for stopping fuel injection (fuel cut) during deceleration traveling in a vehicle using an internal combustion engine as a traveling engine.

Here, when the pressure of the fuel supplied to the fuel injection valve (supply fuel pressure) is high, the minimum injection amount that can be injected by opening the valve once cannot be sufficiently reduced. On the other hand, if the fuel cut is started in a state where the supply fuel pressure is high, the supply fuel pressure may remain high even when the injection is restarted. In that case, the output torque of the engine cannot be sufficiently reduced when the injection is restarted.

As a countermeasure for this, Patent Document 1 describes the cylinder reduction control described below. The cylinder reduction control targets a multi-cylinder engine, and reduces the injection target to some cylinders when the injection is restarted after the fuel is cut. According to this, even when the injection is restarted in a situation where the minimum injection amount cannot be sufficiently reduced, the deterioration of exhaust emissions due to the enrichment of the air-fuel ratio can be suppressed by reducing the number of cylinders to be injected, that is, the cylinders to be burned.

JP-A-2018-141384

Although there is no description in Patent Document 1 regarding the control of the throttle valve during the fuel cut execution period (cut period), it is possible to minimize the opening degree of the throttle valve during the cut period so that the engine brake can be greatly applied. It is common. Therefore, when the injection is restarted in a situation where a large output torque is required, the throttle valve opening degree is increased when the injection is restarted, but the response delay in which the intake amount rises to a desired amount becomes large. Then, in the situation where the minimum injection amount cannot be sufficiently reduced as described above, combustion occurs in a state where the intake amount is insufficient with respect to the injection amount during the period of the intake response delay (rich combustion).

In short, if the cylinder reduction control is executed when the injection is restarted after the cut period, the air-fuel ratio enrichment can be suppressed even when the supply fuel pressure is high, but the intake response delay period immediately after the injection restart causes rich combustion, resulting in deterioration of exhaust emissions and accelerated running. It causes sexual deterioration.

The present disclosure has been made in view of the above problems, and the purpose of the present disclosure is to make it possible to suppress the enrichment of the air-fuel ratio when the injection is restarted after the fuel is cut, and to deteriorate the exhaust emission immediately after the restart of the injection and to accelerate the vehicle. The purpose of the present invention is to provide an in-vehicle engine control device capable of suppressing deterioration of sexuality.

One disclosed means of achieving the above objectives is:
A plurality of cylinders (10) mounted on a vehicle and forming a combustion chamber (11),
A direct-injection fuel injection valve (20), which is attached to each of the cylinders and injects fuel directly into the combustion chamber,
A delivery pipe (30) that distributes the accumulated fuel to each of the fuel injection valves,
Throttle valve (60) that adjusts the amount of intake air distributed to each of the combustion chambers,
In an in-vehicle engine control device applied to an engine system equipped with
A fuel cut control unit (71) that executes a fuel cut such as stopping fuel injection from a fuel injection valve while the vehicle is running, and a fuel cut control unit (71).
An opening control unit (72) that controls the opening of the throttle valve, which is the opening of the throttle valve when the fuel is cut, and an opening control unit (72).
A cylinder reduction control unit (73) that executes a cylinder reduction control that reduces the fuel injection target to a part of a plurality of cylinders when the fuel cut is completed and the fuel injection is restarted.
With
The pressure of the fuel accumulated in the delivery pipe during the fuel cut is set as the cut fuel pressure, the state where the cut fuel pressure is less than the predetermined pressure is set as the low pressure standby state, and the cut fuel pressure is equal to or higher than the predetermined pressure. The state in which it is set to the high-voltage standby state is set.
The cylinder reduction control unit executes the cylinder reduction control on the condition that it is in the high-voltage standby state.
The opening degree control unit is an in-vehicle engine control device that increases the opening degree at the time of cutting in the high pressure standby state as compared with the low pressure standby state.

The control device executes the cylinder reduction control when the injection is restarted, provided that it is in the high pressure standby state. Therefore, when the minimum injection amount cannot be sufficiently reduced due to the high supply fuel pressure, the deterioration of exhaust emissions due to the enrichment of the air-fuel ratio can be suppressed by reducing the number of cylinders to be burned.

In addition, the control device increases the opening degree at the time of cutting in the high pressure standby state. According to this, since the intake amount at the time of restarting the injection is large, it is possible to shorten the response delay in which the intake amount rises to a desired amount immediately after the restart of the injection. Therefore, the period of rich combustion immediately after the restart of injection, which is caused by the delay in intake response, can be shortened.

As described above, according to the above control device, it is possible to suppress the enrichment of the air-fuel ratio when the injection is restarted after the fuel is cut, and it is possible to shorten the intake response delay, and it is possible to suppress the deterioration of the exhaust emission and the deterioration of the acceleration running performance immediately after the restart of the injection. Can be realized.

The reference numbers in parentheses are merely examples of the correspondence with the specific configuration in the embodiment described later, and do not limit the technical scope at all.

The schematic diagram which shows the structure of the control device which concerns on 1st Embodiment, and the engine system to which the control device is applied. The flowchart which shows the control procedure which concerns on 1st Embodiment. A time chart showing changes in various values when the control according to the first embodiment is executed. The flowchart which shows the control procedure which concerns on 2nd Embodiment. A time chart showing changes in various values when the control according to the second embodiment is executed.

Hereinafter, a plurality of embodiments of the present disclosure will be described with reference to the drawings. By assigning the same reference numerals to the corresponding components in each embodiment, duplicate description may be omitted. When only a part of the configuration is described in each embodiment, the configuration of the other embodiment described above can be applied to the other parts of the configuration.

(First Embodiment)
The engine system shown in FIG. 1 is mounted on a vehicle and functions as a traveling drive source of the vehicle. The engine system includes a cylinder 10, a fuel injection valve 20, a delivery pipe 30, a high pressure pump 40, an intake pipe 50, a throttle valve 60, and an electronic control device (ECU 70). The ECU 70 corresponds to an "vehicle-mounted engine control device" that controls the operation of the fuel injection valve 20, the high-pressure pump 40, the throttle valve 60, and an ignition device (not shown).

A plurality of cylinders 10 are provided, and a fuel injection valve 20 is attached to each of the cylinders 10. The fuel injection valve 20 injects fuel directly into the combustion chamber 11 inside the cylinder 10. The fuel injected into the combustion chamber 11 forms an air-fuel mixture together with the intake air, and is ignited by the ignition device and burned. In short, the engine system shown in FIG. 1 is a multi-cylinder engine, which is an ignition ignition type gasoline engine using a direct injection type fuel injection valve 20.

The high-pressure pump 40 pressurizes the liquid fuel (gasoline) stored in a fuel tank (not shown) and pumps it to the delivery pipe 30. The delivery pipe 30 has a function of accumulating the fuel pumped from the high-pressure pump 40 and distributing it to each fuel injection valve 20.

A relief valve and a fuel pressure sensor 31 (not shown) are attached to the delivery pipe 30. The fuel pressure sensor 31 detects the supplied fuel pressure and outputs it to the ECU 70. The relief valve has a mechanical structure that closes by the elastic force of the spring. When the pressure of the fuel (supply fuel pressure) in the delivery pipe 30 becomes higher than the upper limit pressure, the relief valve operates against the elastic force. As a result, a part of the fuel in the delivery pipe 30 is returned to the fuel tank, and the supply fuel pressure becomes lower than the upper limit pressure. The relief valve avoids damage to various pipes, etc. due to the supply fuel pressure exceeding the upper limit pressure.

An intake manifold 51 is connected to the downstream end of the intake pipe 50. The air flowing through the intake pipe 50 is distributed to each cylinder 10 by the intake manifold 51 and flows into the combustion chamber 11 as intake air. The intake manifold 51 is set to evenly distribute the intake air to each cylinder 10.

The throttle valve 60 is attached to the intake pipe 50 and adjusts the amount of intake air distributed to each of the combustion chambers 11. Therefore, if the opening degree (throttle opening degree) of the throttle valve 60 is increased to increase the intake amount flowing through the intake pipe 50, each of the intake amounts distributed to the plurality of combustion chambers 11 increases.

The ECU 70 has a processor 70a and a memory 70b. The processor 70a executes various processes according to the program stored in the memory 70b. The memory 70b is also called a storage medium. The memory 70b is a non-transitional and substantive storage medium that non-temporarily stores "programs and / or data" that can be read by the processor 70a. The storage medium is provided by a semiconductor memory, a magnetic disk, an optical disk, or the like. The program may be distributed by itself or as a storage medium in which the program is stored.

The ECU 70 calculates the rotation speed (engine rotation speed) of the crankshaft of the engine per unit time based on the crank angle signal output from the crank angle sensor 81. Further, the ECU 70 calculates the engine output (required load) required by the driver based on the pedal depression amount signal output from the accelerator pedal sensor 82.

The ECU 70 calculates a target torque, which is a target value of the engine output torque, based on the engine speed and the required load. Further, the ECU 70 calculates an intake amount (target intake amount) corresponding to the target torque, and controls the operation of the throttle valve 60 so as to have an opening degree corresponding to the target intake amount. Specifically, the ECU 70 controls the drive of the throttle motor 61 to control the throttle opening degree to an opening degree corresponding to the target intake amount.

Further, the ECU 70 calculates a fuel injection amount (target injection amount) corresponding to an intake amount detected by an air flow meter (not shown). Here, in the case of an ignition ignition type engine, the ratio of the air-fuel mixture (air-fuel ratio) of the air-fuel mixture burned in the combustion chamber 11 greatly affects the exhaust emission and the accelerated running performance. In view of this point, the above-mentioned target injection amount is set based on the intake amount so as to be the air-fuel ratio set from the viewpoint of exhaust emission and acceleration running performance. Then, the ECU 70 controls the fuel injection valve 20 to be opened only for the target injection amount set in this way and the energization time corresponding to the supply fuel pressure detected by the fuel pressure sensor 31.

When the target injection amount is the same, the higher the supply fuel pressure, the shorter the energization time is set. This is because even if the valve opening time is the same, the higher the supplied fuel pressure, the larger the amount injected in one valve opening. Although the injection amount can be reduced by shortening the energization time, there is a limit to shortening the energization time, so there is also a limit to reducing the injection amount. Therefore, the higher the supply fuel pressure, the more the minimum injection amount cannot be made sufficiently small.

Further, the ECU 70 has a fuel cut control unit 71, an opening degree control unit 72, and a cylinder reduction control unit 73 shown in FIG. The ECU 70 when executing the fuel cut, the opening degree control at the time of cutting, and the cylinder reduction control unit described below corresponds to each of the fuel cut control unit 71, the opening degree control unit 72, and the cylinder reduction control unit 73.

The fuel cut by the fuel cut control unit 71 is a control for stopping the fuel injection during deceleration running. For example, the fuel cut is executed when the accelerator pedal depression amount is zero, the vehicle speed is at least a predetermined value, and the engine speed is at least a predetermined value. As a result, fuel consumption can be reduced.

The cutting opening degree control by the opening degree control unit 72 is the control of the cutting opening degree which is the opening degree of the throttle valve 60 when the fuel cut is being executed. The fuel pressure at the time of cutting used in the following description is the fuel supply pressure at the time of executing the fuel cut. The low pressure standby state is a state in which the fuel pressure at the time of cutting is less than a predetermined pressure. The high-pressure standby state is a state in which the fuel pressure at the time of cutting is equal to or higher than a predetermined pressure.

The opening degree control unit 72 controls the throttle valve opening degree (opening at the time of cutting) in the fuel cut period to the minimum opening degree in the low pressure standby state. Specific examples of the minimum opening degree include an opening degree (idle opening degree) when the engine is idle-operated. On the other hand, in the high-voltage standby state, the opening degree at the time of cutting is increased as compared with the case of the low-voltage standby state.

The cylinder reduction control by the cylinder reduction control unit 73 is a control that reduces the fuel injection target to a part of the plurality of cylinders 10 when the fuel cut is finished and the fuel injection is restarted. In other words, the cylinder reduction control is a control that prohibits all cylinders 10 from being allowed to inject fuel, thereby limiting the engine output torque. The cylinder reduction control is executed on condition that the high voltage standby state is set.

FIG. 2 is a flowchart showing a processing procedure in which the ECU 70 executes the fuel cut, the opening degree control at the time of cutting, and the cylinder reduction control described above. The process of FIG. 2 is repeatedly executed at a predetermined cycle during the engine operation period. Specific examples of the predetermined cycle include the calculation cycle of the processor 70a and the rotation angle cycle of the crankshaft.

First, in step S10 of FIG. 2, it is determined whether or not it is determined to start the fuel cut. In short, it is determined whether or not the above-mentioned fuel cut condition is satisfied. If it is determined that the conditions are satisfied, the fuel cut control unit 71 starts the fuel cut in the next step S20.

In the following step S30, it is determined whether or not the supply fuel pressure (actual fuel pressure) detected by the fuel pressure sensor 31 is larger than the predetermined pressure Pth. In short, it is determined whether the actual fuel pressure is in the high pressure standby state higher than the predetermined pressure Pth or in the low pressure standby state in which the actual fuel pressure is equal to or lower than the predetermined pressure Pth. When the low-voltage standby state is determined, the opening at the time of cutting is controlled to the minimum opening (for example, the idle opening) as described above. Specifically, the required intake air amount is set to the intake air amount corresponding to the idle opening degree.

On the other hand, when it is determined that the high voltage standby state is set, the cylinder reduction control flag is set to ON in the subsequent step S32. In the following step S40, the opening degree at the time of cutting is controlled to an opening degree larger than the minimum opening degree. Specifically, the required intake air amount is increased from the intake air amount corresponding to the idle opening degree. Further, in step S40, the amount of increase in the opening degree at the time of cutting, that is, the amount of increase in the required intake amount is variably set according to the actual fuel pressure acquired in step S30. Specifically, the higher the actual fuel pressure, the larger the amount of increase in the opening opening at the time of cutting. For example, the opening at the time of cutting may be increased stepwise according to the actual fuel pressure, or the opening at the time of cutting may be increased linearly in proportion to the actual fuel pressure.

In other words, if a negative determination is made in step S30, the opening degree control at the time of cutting by the opening degree control unit 72 is controlled to the opening degree at the time of cutting in the low voltage standby state. On the other hand, if an affirmative determination is made in step S30, the opening degree control at the time of cutting by the opening degree control unit 72 is controlled to the opening degree at the time of cutting in the high voltage standby state.

In the following step S50, it is determined whether or not it is determined to finish the fuel cut and restart (return) the fuel injection. In short, it is determined whether or not the fuel cut condition is not satisfied because, for example, the driver depresses the accelerator pedal or the engine speed drops below a predetermined value. When it is determined that the condition is not satisfied, that is, when it is determined to restart the fuel injection, it is determined in the next step S55 whether or not the cylinder reduction control flag is turned on. When it is determined that the cylinder reduction control flag is turned on, in the next step S60, it is determined whether or not the required torque is smaller than the torque corresponding to the current intake amount. The intake amount used for this determination may be the intake amount detected by the air flow meter (actual intake amount) or the intake amount corresponding to the opening degree at the time of cutting (estimated intake amount).

If an affirmative determination is made in step S60, in the next step S70, fuel injection is restarted and engine combustion is restarted (reduced cylinder restart) while executing cylinder reduction control by the cylinder reduction control unit 73. On the other hand, if a negative determination is made in step S60, in the next step S80, regardless of whether or not the engine is restarted from the high-pressure standby state, fuel injection is restarted while the cylinder reduction control is prohibited, and engine combustion is performed. Is restarted (normal restart). Further, even when it is determined in step S55 that the cylinder reduction control flag is not turned on, the normal restart in step S80 is performed.

FIG. 3 is a time chart showing an example of changes in various values when fuel cut, cut opening control, and cylinder reduction control are executed. In the example of FIG. 3, the fuel cut is roughly started at the time of t10, the fuel injection is restarted at the time of t30, and the high pressure standby state is in the fuel cut period from the time of t10 to the time of t30. Therefore, the opening degree at the time of cutting during the fuel cutting period is increased, and the cylinder reduction control is executed when the injection is restarted.

More specifically, by the time of t10, the accelerator pedal is depressed and the engine speed increases, and the supply fuel pressure also increases with the increase. Then, at t10, the amount of depression of the accelerator pedal is operated to zero. The engine speed Na at t10 is higher than the predetermined value, which is the condition for fuel cut. Therefore, the fuel cut condition is satisfied at t10, and the fuel cut execution flag is switched from off to on. Further, at t30 when the accelerator pedal is depressed, the fuel cut condition is no longer satisfied, and the fuel cut execution flag is switched from on to off.

Even when the accelerator pedal is not depressed, when the engine speed decreases with the fuel cut and the lower limit threshold value Nb is reached, the fuel cut condition is not satisfied and fuel injection is restarted. The lower limit threshold value Nb is set to, for example, the idle speed.

In the example of FIG. 3, the supply fuel pressure at t10 when the fuel cut is started is higher than the predetermined pressure Pth used in the determination in step S30. Due to the structure of the delivery pipe 30 shown in FIG. 1, the supply fuel pressure at t10 is maintained until fuel is injected from the fuel injection valve 20. Therefore, the high-pressure standby state is maintained for a period from t10 when the fuel cut starts to t50 when the supply fuel pressure decreases and reaches the predetermined pressure Pth as the injection is restarted. That is, the cylinder reduction control flag is set to ON during the period from the time t10 to the time t50.

Among the periods in which the cylinder reduction control flag is set to ON, the required intake amount is increased by step S40 in FIG. 2 during the fuel cut period. In the example of FIG. 3, the required intake amount Qb is set to be larger than the required intake amount Qa in the low pressure standby state. Along with this, the actual intake amount, which is the intake amount detected by the air flow meter, is also maintained at the actual intake amount Qb, which is larger than the actual intake amount Qa in the low pressure standby state.

The inclination (speed) at which the actual intake air amount decreases from the time t10 when the fuel cut starts is the same in the low pressure standby state and the high pressure standby state when the required intake air amount is the same. Therefore, at t20, when the actual intake amount drops to the target intake amount during the fuel cut period, the timing in the high-pressure standby state is earlier than that in the low-pressure standby state. Similarly, the inclination at which the actual intake air amount rises to the required intake air amount from the time t30 when the injection is restarted is the same in the low pressure standby state and the high pressure standby state. Therefore, at t40, when the actual intake amount rises to the target intake amount immediately after the restart of injection, the timing in the high-pressure standby state is earlier than that in the low-pressure standby state.

In the example of FIG. 3, it is assumed that the engine output torque required at the time of restarting combustion is smaller than the engine output torque corresponding to the required intake amount Qb due to the opening degree at the time of cutting. That is, it is assumed that a positive determination is made in step S60 of FIG. In addition, the supply fuel pressure becomes smaller than the predetermined pressure Pth at t50 after t40. Therefore, until the time of t50, the minimum injection amount has not been sufficiently reduced, and the air-fuel ratio enrichment is suppressed by the cylinder reduction control.

Hereinafter, the effect of the display device by providing the above-described configuration will be described.

The ECU 70 according to the present embodiment executes the cylinder reduction control when the injection is restarted, provided that it is in the high pressure standby state. Therefore, when the minimum injection amount cannot be sufficiently reduced due to the high supply fuel pressure, the deterioration of exhaust emissions due to the enrichment of the air-fuel ratio can be suppressed by reducing the number of cylinders 10 to be burned.

Here, in the response delay period in which the intake air amount rises to the desired amount Qc, the minimum injection amount cannot be sufficiently reduced due to the high supply fuel pressure as described above, and the intake air amount is still higher than the desired amount Qc. Few. Therefore, it is unavoidable that rich combustion occurs during the response delay period. In view of this point, the ECU 70 according to the present embodiment increases the opening degree at the time of cutting in the high pressure standby state, so that the intake amount at the time of restarting injection (at the time of t30 in FIG. 3) increases. Therefore, immediately after restarting the injection, the response delay time in which the intake air amount rises to the desired amount Qc, that is, the time from the t30 time point to the t40 time point can be shortened. Therefore, the period of rich combustion caused by the delay in intake response can be shortened.

As described above, according to the present embodiment, the output torque can be reduced when the injection is restarted after the fuel is cut by the cylinder reduction control, and the intake response delay can be shortened by the control to increase the opening degree at the time of cutting, and the exhaust emission is deteriorated. And it is possible to suppress the deterioration of acceleration running performance.

Here, the higher the fuel pressure at the time of cutting, the larger the minimum injection amount at the time of restarting the injection. Therefore, the injection amount in the response delay period from the time t30 to the time t40 increases as the fuel pressure at the time of cutting increases. Therefore, there is a concern that the higher the fuel pressure at the time of cutting, the greater the degree of enrichment during the response delay period.

In response to this concern, in the present embodiment, the opening degree control unit 72 increases the opening degree at the time of cutting as the fuel pressure at the time of cutting becomes higher in the high pressure standby state. According to this, since the intake amount at the time of restarting the injection (at the time of t30) can be increased, the above concern can be suppressed.

Here, the engine output torque required at the time of restarting combustion may be larger than the engine output torque according to the intake amount Qb due to the opening degree at the time of cutting. In this case, the actual injection amount does not become larger than the target injection amount even in the period before the time point t50 when the supply fuel pressure is larger than the predetermined pressure Pth. Therefore, cylinder reduction control is unnecessary.

In view of this point, in the present embodiment, when the engine output torque required at the time of restarting combustion is larger than the engine output torque according to the intake amount Qb due to the opening degree at the time of cutting, it is the case of the high pressure standby state. However, the cylinder reduction control is prohibited. That is, when a negative determination is made in step S60 of FIG. 2, fuel injection is restarted while prohibiting cylinder reduction control even in the high-pressure standby state. Therefore, it is possible to avoid unnecessarily executing the cylinder reduction control.

(Second Embodiment)
In the first embodiment, in the high pressure standby state, the opening degree at the time of cutting is increased at the start of the fuel cutting period. Specifically, at t10 in FIG. 3, the required intake air amount is made larger than the idle opening degree. On the other hand, in the present embodiment, even in the high pressure standby state, immediately after the start of the fuel cut period, the control is performed so as to maintain the cut opening (first opening) in the low pressure standby state. After that, the second opening degree, which is larger than the first opening degree, is controlled so as to maintain the opening degree at the time of cutting.

Specifically, as shown in FIG. 4, by adding the process of step S35 to the flowchart of FIG. 2, the timing of making the opening degree at the time of cutting larger than the minimum opening degree is delayed. In step S35, it is determined whether or not the engine speed NE is smaller than the threshold value Nc (see FIG. 5). The threshold value Nc is set to a value higher than the idle rotation speed NIDL (lower limit threshold value Nb) by a predetermined value A.

When it is determined that the engine speed NE is smaller than the threshold value Nc, the required intake amount is increased in step S40. If it is not determined that the engine speed NE is smaller than the threshold value Nc, the determination process of step S50 is executed without executing the process of step S40. In short, when the engine speed decreases with the start of fuel cutting, the opening degree at the time of cutting is controlled to the first opening degree during the period when the engine speed decreases to the threshold value Nc. After that, in the period after t25 when the threshold value is lowered to Nc, the opening degree at the time of cutting is controlled to the second opening degree (see FIG. 5).

As described above, in the present embodiment, the opening degree control unit 72 during the high-voltage standby period maintains the opening degree at the time of cutting at the first opening degree and then at the second opening degree larger than the first opening degree. This second opening is set to a larger opening than in the low pressure standby state.

According to this, since the first opening degree is maintained at the beginning of the fuel cut, the engine brake can be greatly applied as compared with the case where the second opening degree is maintained. Therefore, the deceleration by the engine brake at the beginning of the fuel cut can be improved. Nevertheless, since it is maintained at the second opening after being maintained at the first opening, the same effect as that of the first embodiment such that the intake response delay can be shortened is exhibited.

Further, in the present embodiment, the opening degree control unit 72 switches from the first opening degree to the second opening degree at the timing when the engine speed drops beyond the threshold value Nc. That is, the engine speed is used as a condition for switching to the second opening degree. Here, one of the conditions for fuel cut is "the engine speed is equal to or higher than the lower limit threshold value Nb". That is, the engine speed is used as a condition for fuel cut. As described above, in the present embodiment, the second opening is switched using the same physical quantity as the physical quantity (engine speed) used for the fuel cut condition. Therefore, it is possible to eliminate the concern that the switching to the second opening cannot be made in time when the injection is restarted, and it is possible to improve the certainty of increasing the intake amount during the cut period.

(Other embodiments)
Although the plurality of embodiments of the present disclosure have been described above, not only the combination of the configurations specified in the description of each embodiment but also the plurality of embodiments even if the combination is not specified if there is no problem in the combination. Can be partially combined with each other. Further, an unspecified combination of the configurations described in the plurality of embodiments and modifications is also disclosed by the following description.

In the second embodiment, the first opening degree is set to the opening degree at the time of cutting in the low voltage standby state. On the other hand, the first opening may be larger than the opening at the time of cutting in the low pressure standby state as long as it is smaller than the second opening.

In the second embodiment, the timing of switching from the first opening degree to the second opening degree is determined by the engine speed. On the other hand, for example, when the state of maintaining the first opening degree elapses for a predetermined time set in advance, the second opening degree may be switched to.

In the first embodiment, the opening degree at the time of cutting according to the high pressure standby state is set larger as the fuel pressure at the time of cutting is higher. On the other hand, the opening degree at the time of cutting related to the high voltage standby state may be fixed and set to a preset opening degree.

10 cylinders, 11 combustion chamber, 20 fuel injection valve, 30 delivery pipe, 60 throttle valve, 71 fuel cut control unit, 72 opening control unit, 73 cylinder reduction control unit, Nc threshold value. 70 ECU (vehicle-mounted engine control unit).

Claims (5)

A plurality of cylinders (10) mounted on a vehicle and forming a combustion chamber (11),
A direct-injection fuel injection valve (20) attached to each of the cylinders and directly injecting fuel into the combustion chamber,
A delivery pipe (30) that distributes the accumulated fuel to each of the fuel injection valves, and
A throttle valve (60) that adjusts the amount of intake air distributed to each of the combustion chambers, and
In an in-vehicle engine control device applied to an engine system equipped with
A fuel cut control unit (71) that executes a fuel cut such as stopping fuel injection from the fuel injection valve while the vehicle is running, and a fuel cut control unit (71).
An opening control unit (72) that controls a cutting opening, which is an opening of the throttle valve when the fuel cut is being executed, and an opening control unit (72).
When the fuel cut is completed and the fuel injection is restarted, the cylinder reduction control unit (73) that executes the cylinder reduction control that reduces the fuel injection target to a part of the plurality of cylinders, and the cylinder reduction control unit (73).
With
The pressure of the fuel accumulated in the delivery pipe during the fuel cut is set as the cut fuel pressure, and the state in which the cut fuel pressure is less than the predetermined pressure (Pth) is set as the low pressure standby state, and the cut is performed. The state in which the hourly fuel pressure is equal to or higher than the predetermined pressure is defined as the high pressure standby state.
The cylinder reduction control unit executes the cylinder reduction control on condition that it is in the high pressure standby state.
The opening degree control unit is an in-vehicle engine control device that increases the opening degree at the time of cutting in the case of the high pressure standby state as compared with the case of the low pressure standby state. The vehicle-mounted engine control device according to claim 1, wherein the opening degree control unit increases the cutting opening degree as the cutting fuel pressure increases in the high-pressure standby state. When the engine output torque required at the time of restarting combustion is larger than the engine output torque according to the intake amount due to the opening at the time of cutting, the cylinder reduction control is prohibited even in the high pressure standby state. The vehicle-mounted engine control device according to claim 1 or 2. The opening degree control unit during the high-voltage standby state maintains the opening at the time of cutting at the first opening, and then maintains the opening at a second opening larger than the first opening.
The vehicle-mounted engine control device according to any one of claims 1 to 3, wherein at least the second opening degree is set to a larger opening degree than in the case of the low voltage standby state. The vehicle-mounted engine control device according to claim 4, wherein the opening degree control unit switches from the first opening degree to the second opening degree at a timing when the engine speed drops beyond the threshold value (Nc).

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