JP2020159277A - Air amount controller, suction/exhaust device and vehicle - Google Patents

Abstract

To provide an air amount controller capable of suppressing surging occurring in a compressor, a suction/exhaust device, and a vehicle.SOLUTION: An air amount controller of a suction/exhaust device having a supercharger in a vehicle, comprises a determination unit that determines the possibility of surging in the supercharger based on parameters related to the operation of an internal combustion engine during acceleration operation of the vehicle, and an adjustment unit that adjusts an amount of suctioned air suctioned into the internal combustion engine so that it is larger than a surging occurrence threshold according to a determination result of the determination unit.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to an air volume control device, an intake / exhaust device, and a vehicle.

Conventionally, an intake / exhaust device having a supercharger composed of a compressor and a turbine is known (see, for example, Patent Document 1). In this technology, the fuel injection amount is reduced when the vehicle is decelerating (when the accelerator is off), and the recirculation path portion is fully closed to suppress surging that occurs in the compressor.

Japanese Unexamined Patent Publication No. 2004-360525

By the way, when the vehicle climbs a slope, even if the accelerator is turned on for acceleration, the vehicle may decelerate due to the gravity of the vehicle, and the above surging may occur. In the case of the configuration described in Patent Document 1, since such surging cannot be suppressed, the configuration that suppresses surging has a certain limit.

An object of the present disclosure is to provide an air amount control device, an intake / exhaust device, and a vehicle capable of suppressing surging generated in a compressor.

The air amount control device according to the present disclosure is
An air amount control device for an intake / exhaust device having a supercharger in a vehicle.
A determination unit that determines the possibility of surging in the turbocharger based on parameters related to the operation of the internal combustion engine during the acceleration operation of the vehicle.
An adjustment unit that adjusts the amount of intake air taken into the internal combustion engine so as to be larger than the surging occurrence threshold value according to the determination result of the determination unit.
To be equipped.

The intake / exhaust device according to the present disclosure is
An intake pipe that draws air into the internal combustion engine,
An exhaust pipe that exhausts the exhaust gas of the internal combustion engine and
A supercharger having a compressor provided in the intake pipe and a turbine provided in the exhaust pipe, and
A recirculation path portion that recirculates the exhaust gas of the exhaust pipe toward the intake pipe,
With the above air volume control device,
To be equipped.

The vehicle pertaining to this disclosure
The above intake / exhaust device is provided.

According to the present disclosure, surging generated in the compressor can be suppressed.

It is a figure which shows the intake / exhaust device of the vehicle to which the air amount control device which concerns on embodiment of this disclosure is applied. It is a figure which shows the transition of the intake amount with respect to the pressure ratio. It is a flowchart which shows the operation example of the air amount control in an air amount control device. It is a figure which shows the ideal line of the transition of the intake amount with respect to the pressure ratio. It is a figure which shows the relationship between the rotation speed of an internal combustion engine, and the fuel injection amount.

Hereinafter, the present embodiment will be described in detail with reference to the drawings. FIG. 1 is a diagram showing an intake / exhaust device 1 of a vehicle V to which the air amount control device 100 according to the embodiment of the present disclosure is applied.

As shown in FIG. 1, the intake / exhaust device 1 of the vehicle V includes an internal combustion engine 10, an intake pipe 20, an exhaust pipe 30, a cooling unit 40, a recirculation path unit 50, a supercharger 60, and air. It has a quantity control device 100.

The internal combustion engine 10 is, for example, a diesel engine mounted on a vehicle V, and is connected to an intake pipe 20 and an exhaust pipe 30. The intake pipe 20 takes in outside air to the internal combustion engine 10.

The exhaust pipe 30 exhausts the exhaust gas generated by the internal combustion engine 10. An excess air ratio detection unit 31 is provided on the upstream side of the turbine 62 of the exhaust pipe 30. The excess air rate detection unit 31 is, for example, a lambda sensor, and detects the excess air rate in the internal combustion engine 10. The excess air ratio detection unit 31 may be provided on the downstream side of the turbine 62 of the exhaust pipe 30.

The cooling unit 40 is arranged in the intake pipe 20 and cools the outside air compressed by the compressor 61 described later in the intake pipe 20.

The recirculation path portion 50 is a path that branches from the exhaust pipe 30 and recirculates the exhaust gas in the exhaust pipe 30 toward the intake pipe 20.

The recirculation path section 50 is provided with a recirculation valve 51 that adjusts the flow rate of the exhaust gas returned from the exhaust pipe 30 to the intake pipe 20 via the recirculation path section 50. Under the control of the air amount control device 100, the recirculation valve 51 changes the open / closed state according to the amount of air taken into the internal combustion engine 10 (hereinafter, referred to as "intake amount") during the acceleration operation of the vehicle V. The flow rate of the exhaust gas returned from the exhaust pipe 30 to the intake pipe 20 is adjusted by adjusting the opening degree.

The supercharger 60 includes a compressor 61, a turbine 62, and a connection portion 63. The compressor 61 is provided in the intake pipe 20.

The turbine 62 is provided in the exhaust pipe 30, and a turbine impeller (not shown) is rotated by the exhaust gas discharged from the internal combustion engine 10.

The compressor 61 and the turbine 62 are connected by a connecting portion 63, and the compressor impeller (not shown) and the turbine impeller of the compressor 61 rotate integrally by a rotating shaft (not shown). As a result, in the compressor 61, the compressor impeller rotates to compress the outside air sent to the intake pipe 20 and send it to the internal combustion engine 10.

The air amount control device 100 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and an input / output circuit (not shown). The air amount control device 100 is configured to perform control for suppressing surging generated in the supercharger 60 (compressor 61) based on a preset program. The air amount control device 100 has a determination unit 110 and an adjustment unit 120.

The determination unit 110 determines the possibility of surging in the compressor 61 based on the relationship between the intake amount and the pressure ratio (hereinafter referred to as the pressure ratio) at the inlet and outlet of the compressor 61 during the acceleration operation of the vehicle V. judge.

The intake amount is the amount of air based on the detection result of the intake amount sensor (not shown) provided in the intake pipe 20. The pressure ratio is the ratio of the pressure on the outlet side of the compressor 61 to the pressure on the inlet side of the compressor 61. The pressure on the inlet side of the compressor 61 and the pressure on the outlet side of the compressor 61 are pressures based on the detection results of a pressure sensor (not shown) provided at the corresponding portion of the intake pipe 20. As the pressure ratio, in addition to the detection result of the pressure sensor, a numerical value such as atmospheric pressure is used as the pressure on the inlet side of the compressor 61, and an estimation model or data map provided based on the operating status of the internal combustion engine 10 is used. You may.

It is known that surging occurs in the compressor 61 based on the relationship between the intake amount and the pressure ratio in the vehicle V. For example, as shown in FIG. 2, when the vertical axis is the pressure ratio and the horizontal axis is the intake amount, the solid line S shown in FIG. 2 separates a region where surging occurs and a region where surging does not occur.

The solid line S changes so that the pressure ratio increases as the intake amount increases. In FIG. 2, the region on the left side of the solid line S is the region where surging occurs, and the region on the right side of the solid line S is the region where surging does not occur. That is, the solid line S indicates the surging occurrence threshold value described later. In FIG. 2, each line is simplified and illustrated in consideration of ease of understanding.

When surging occurs in the compressor 61, the air compressed by the compressor 61 may flow back to the compressor 61 side and damage the compressor 61.

As a situation where such surging occurs, during the acceleration operation of the vehicle V, for example, when the vehicle V climbs a slope, the accelerator is on for acceleration, but the vehicle V decelerates due to the gravity of the vehicle V. There are cases like this. In this case, for example, as shown by the broken line L1 shown in FIG. 2, the intake amount decreases from A, which is an arbitrary amount, due to the deceleration of the vehicle V, and enters the region on the left side of the solid line S.

When the recirculation valve 51 is open, the above exhaust gas amount also fluctuates according to the fluctuation of the intake amount, so that the balance between the intake amount and the exhaust gas amount is lost, the intake amount becomes unstable, and surging occurs. Occurs continuously.

In the present embodiment, the determination unit 110 determines that surging occurs when the intake amount becomes equal to or less than the surging occurrence threshold. The surging occurrence threshold value is the amount of air that serves as a reference for surging to occur in the compressor 61, and can be arbitrarily set for each pressure ratio as shown in the solid line S, for example. The surging occurrence threshold value may be set as shown by the solid line S in FIG. 2, or may be set as a line shifted to the right of the solid line S. In other words, the surging occurrence threshold value may be set to be the boundary line between the area where surging occurs and the area where surging does not occur, or a line shifted from the boundary line to the side where surging does not occur. It may be set to be.

As a result, the possibility of surging can be quickly determined during the acceleration operation of the vehicle V.

The adjusting unit 120 adjusts the intake amount so as to be larger than the surging occurrence threshold value by controlling the recirculation valve 51 in the recirculation path unit 50. Specifically, when the determination unit 110 determines that surging occurs, the adjustment unit 120 adjusts so that the amount of fresh air taken into the intake pipe 20 is increased as compared with that before the adjustment. That is, the adjusting unit 120 controls the recirculation valve 51 of the recirculation path unit 50 so as to reduce the recirculation amount of the exhaust gas of the recirculation path unit 50 as compared with that before the adjustment. More specifically, the adjusting unit 120 closes the recirculation valve 51 of the recirculation path unit 50 to reduce the amount of exhaust gas recirculated to the intake pipe 20 to zero.

By doing so, as shown in the solid line L2 shown in FIG. 2, after the intake amount has changed to the side of the solid line S (see the solid line arrow), the amount of fresh air increases as the amount of exhaust gas recirculated decreases. .. As a result, the amount of intake air changes to the right side from the solid line S, so that it is possible to suppress the continuous occurrence of surging when the vehicle V is accelerating.

Further, the adjusting unit 120 restarts the control related to the recirculation in the recirculation path unit 50, for example, when the difference between the intake amount and the surging occurrence threshold becomes an allowable amount. The permissible amount can be appropriately set to an amount at which the intake amount is considered to be separated from the solid line S to such an extent that surging does not occur.

By doing so, it is possible to smoothly shift to a steady state in which control related to the recirculation of the exhaust gas in the recirculation path portion 50 is performed.

The period for adjusting the intake amount by the adjusting unit 120 (the period for stopping the recirculation path unit 50) may be determined in consideration of the state of the exhaust gas. Further, the determination unit 110 may determine the possibility of surging even when the vehicle V is not accelerating.

An operation example of air amount control in the air amount control device 100 configured as described above will be described. FIG. 3 is a flowchart showing an operation example of air amount control in the air amount control device 100. The process in FIG. 3 is appropriately executed, for example, during the operation of the vehicle V.

As shown in FIG. 3, the control unit 100 acquires the excess air ratio from the excess air ratio detection unit 31 (step S101). Next, the control unit 100 determines whether or not the intake amount based on the excess air ratio is equal to or less than the surging occurrence threshold value (step S102).

As a result of the determination, when the intake amount is larger than the surging occurrence threshold value (step S102, NO), this control ends. On the other hand, when the intake air amount is equal to or less than the surging occurrence threshold value (step S102, YES), the control unit 100 controls the recirculation valve 51 and adjusts to the side where the exhaust gas amount in the recirculation path unit 50 is reduced. The intake amount is adjusted (step S103).

Next, the control unit 100 determines whether or not to restart the recirculation control in the recirculation path unit 50 (step S104). As a result of the determination, when the recirculation control is not restarted (step S104, NO), the process of step S104 is repeated.

On the other hand, when resuming the recirculation control (step S104, YES), the control unit 100 controls the recirculation valve 51 so as to restart the recirculation control (step S105). After that, this control ends.

According to the present embodiment configured as described above, it is possible to suppress the continuous occurrence of surging in the compressor 61, and it is possible to suppress damage to the compressor 61 due to surging. ..

In the above embodiment, the intake air amount is adjusted based on the excess air ratio in the exhaust gas, but the present disclosure is not limited to this. For example, the intake amount may be adjusted based on the detection result of the intake amount sensor provided in the intake pipe 20.

When adjusting the intake amount based on the detection result of the intake amount sensor, the determination unit 110 determines the ideal transition of the intake amount indicated by the solid line I (hereinafter referred to as “ideal line I”) in FIG. Calculated, the possibility of surging is determined according to the amount of deviation of the intake amount toward the boundary line (solid line S shown in FIGS. 2 and 4) of whether or not surging occurs with respect to the ideal line I. You may judge. The reference value of the deviation amount can be appropriately set for each pressure ratio according to the difference between the ideal transition of the intake amount and the surging occurrence threshold value.

For example, FIG. 4 shows an ideal line I in which the intake amount changes from the state of A in the direction of the solid arrow.

The determination unit 110 determines that there is no possibility of surging when the deviation amount with respect to the ideal transition of the intake amount is relatively small as shown by the broken line L3, and determines that surging is not likely to occur, and with respect to the ideal transition of the intake amount as shown by the broken line L4. If the amount of deviation is relatively large, it is determined that surging may occur.

By doing so, it is possible to prevent the occurrence of surging in the compressor 61. The determination by the determination unit 110 may be performed at regular intervals.

Further, in the above embodiment, it is determined that surging occurs at the timing when the intake amount becomes equal to or less than the surging occurrence threshold value, but the present disclosure is not limited to this. The determination unit 110 may determine that surging occurs, for example, at the timing when the intake amount becomes equal to or lower than the surging occurrence threshold and becomes equal to or higher than the surging occurrence threshold again.

For example, in the case of the example of FIG. 2, the determination unit 110 jumps over the solid line S from the state of A and shifts to the left region, and then jumps over the solid line S again and shifts to the right region. , It may be determined that surging occurs.

Even in this way, the occurrence of continuous surging can be suppressed.

Further, in the above embodiment, the intake amount is exemplified as a parameter related to the operation of the internal combustion engine 10, but the present disclosure is not limited to this. For example, it may be the rotation speed of the internal combustion engine 10 and the fuel injection amount.

FIG. 5 is a diagram showing the relationship between the rotation speed of the internal combustion engine 10 and the fuel injection amount. When the vehicle V accelerates, the relationship is as shown in FIG. 5, for example. Specifically, as the number of revolutions of the internal combustion engine 10 increases, the fuel injection amount increases and then decreases.

However, when the vehicle V decelerates due to the weight applied to the vehicle V even though the vehicle V is about to accelerate, such as when climbing a slope, both the internal combustion engine 10 and the fuel injection amount decrease. More specifically, at the stage where both the rotation speed and the fuel injection amount of the internal combustion engine 10 are increasing (see arrow B1), both the rotation speed and the fuel injection amount of the internal combustion engine 10 decrease (see arrow B2). .. This is because a predetermined region at the stage where the fuel injection amount increases (for example, a region where the rotation speed is in the range of R1 to R2) is a region where surging is likely to occur.

Therefore, the determination unit 110 determines that surging may occur when the fuel injection amount exceeds a predetermined value. That is, the determination unit 110 determines that surging may occur when the fuel injection amount includes at least the region where surging occurs (the region where the rotation speed is in the range of R1 to R2).

Then, when it is determined that surging may occur, the adjusting unit 120 adjusts the intake amount by closing the recirculation valve 51 or the like. Even in this way, it is possible to prevent surging from occurring. The timing at which the adjustment of the intake air amount is finished can be appropriately set at the timing after passing the range of R1 to R2.

Further, in the above embodiment, the intake amount is adjusted by adjusting the exhaust gas amount in the recirculation path portion 50, but the present disclosure is not limited to this. For example, when the supercharger 60 is a VGS (Variable Geometry Turbocharger System) type supercharger, the adjusting unit 120 controls a plurality of vane nozzles (not shown) provided on the inlet side of the turbine 62 to take in air. You may adjust the amount.

In this configuration, a plurality of vane nozzles are provided inside the housing of the turbine 62, and are configured to be variably driveable. The control unit 100 controls the drive control of the vane nozzle to variably throttle the inlet area of the turbine 62, thereby controlling the throttle amount of the inlet area of the turbine 62.

For example, when the determination unit 110 determines that surging occurs, the adjustment unit 120 controls the turbine 62 to the side where the inlet area is narrowed to increase the flow velocity of the exhaust gas. As a result, the supercharging pressure is increased, the intake air amount is substantially increased, and the occurrence of surging can be suppressed.

Further, in the above embodiment, control is performed so as to increase the intake air amount, but the present disclosure is not limited to this, and for example, control may be performed so as to decrease the pressure ratio. The supercharger 60 may be appropriately controlled for adjusting the pressure ratio.

The surging occurrence threshold (solid line S shown in FIG. 2) is set so that the pressure ratio corresponding to the decrease in the intake amount decreases, so that the pressure ratio can be decreased without increasing the intake amount. Therefore, it is possible to set the surging occurrence threshold value corresponding to the lowered pressure ratio. Therefore, since the surging occurrence threshold value decreases according to the pressure ratio, it is possible to control the intake amount so as to be larger than the surging occurrence threshold value.

Further, in the above embodiment, the recirculation valve 51 is closed when adjusting the intake air amount, but the present disclosure is not limited to this, and the recirculation valve 51 does not have to be completely closed.

In addition, the above-described embodiments are merely examples of embodiment of the present disclosure, and the technical scope of the present disclosure should not be construed in a limited manner by these. That is, the present disclosure can be carried out in various forms without departing from its gist or its main features.

The air amount control device of the present disclosure is useful as an air amount control device, an intake / exhaust device, and a vehicle capable of suppressing surging generated in a compressor.

1 Intake / exhaust device 10 Internal combustion engine 20 Intake pipe 30 Exhaust pipe 31 Excess air rate detector 40 Cooling unit 50 Recirculation path 51 Recirculation valve 60 Supercharger 61 Compressor 62 Turbine 63 Connection 100 Air volume control device 110 Judgment Part 120 Adjustment part V Vehicle

Claims (8)

An air amount control device for an intake / exhaust device having a supercharger in a vehicle.
A determination unit that determines the possibility of surging in the turbocharger based on parameters related to the operation of the internal combustion engine during the acceleration operation of the vehicle.
An adjustment unit that adjusts the amount of intake air taken into the internal combustion engine so as to be larger than the surging occurrence threshold value according to the determination result of the determination unit.
Air volume control device equipped with. The determination unit determines the possibility of surging based on the relationship between the intake amount and the pressure ratio at the inlet / outlet of the compressor of the turbocharger.
The air amount control device according to claim 1. The determination unit determines that the surging occurs when the intake amount becomes equal to or less than the surging occurrence threshold value.
When the determination unit determines that the surging occurs, the adjusting unit adjusts so that the amount of fresh air taken into the intake pipe is increased as compared with that before the adjustment.
The air amount control device according to claim 2. The surging occurrence threshold is set for each pressure ratio.
The air amount control device according to claim 3. The adjusting unit reduces the amount of recirculation of the exhaust gas in the recirculation path portion of the intake / exhaust device as compared with that before the adjustment, depending on the determination result of the determination unit.
The air amount control device according to any one of claims 1 to 4. The adjusting unit increases the throttle amount of the inlet area in the turbine of the turbocharger according to the determination result of the determination unit as compared with that before the adjustment.
The air amount control device according to any one of claims 1 to 4. An intake pipe that draws air into the internal combustion engine,
An exhaust pipe that exhausts the exhaust gas of the internal combustion engine and
A supercharger having a compressor provided in the intake pipe and a turbine provided in the exhaust pipe, and
A recirculation path portion that recirculates the exhaust gas of the exhaust pipe toward the intake pipe,
The air amount control device according to any one of claims 1 to 6.
Intake and exhaust device equipped with. The intake / exhaust device according to claim 7 is provided.
vehicle.

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