JP6860313B2 - Engine control method and engine - Google Patents

Description

The present invention relates to an engine control method and an engine.

In an engine system that performs exhaust gas recirculation by EGR (Exhaust Gas Recirculation), a part of the exhaust gas is configured to be circulated to the intake air to the engine. Further, when the engine system is provided with a turbocharger, the temperature of the intake air rises because the intake air to the engine is compressed by the turbocharger.

If the intake air temperature becomes too high, the engine may not burn properly, which is not preferable. Therefore, some engine systems are equipped with an intercooler to lower the temperature of the intake air. However, when the intake air is cooled by the intercooler, the water contained in the intake air may be generated as condensed water. If condensed water flows into the engine, the operating performance of the engine may deteriorate. Therefore, it is desirable to suppress the generation of condensed water.

Patent Document 1 discloses a technique for suppressing the generation of condensed water. According to this technique, when it is predicted that condensed water will be generated, it is possible to suppress the generation of condensed water by raising the intake air temperature, lowering the intake pressure, and the like.

International Publication No. 15/151484

According to the technique disclosed in Patent Document 1, when the generation of condensed water is expected, the intake air temperature is raised, so that knocking may occur in the engine. Further, if the intake pressure is lowered, the fuel consumption may be deteriorated. That is, when the control for suppressing the generation of condensed water is performed, the driving performance such as riding comfort and fuel efficiency may deteriorate.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a control method for an engine so as to suppress deterioration of driving performance.

The engine control method of the present invention is an engine control method in which an intercooler is provided in the intake passage, and includes an estimation step for estimating the generation status of condensed water in the intercooler according to the operating condition of the engine, and the generation status of the condensed water. A standard step for determining the permissible standard, a judgment step for determining whether or not the generated state of condensed water meets the permissible standard, and a countermeasure step for implementing countermeasures for condensate water when the generated state does not meet the permissible standard. Be prepared.

According to the present invention, deterioration of driving performance can be suppressed.

FIG. 1 is a schematic configuration diagram of the engine system of the first embodiment. FIG. 2 is a flowchart showing control of measures against condensed water. FIG. 3 is a flowchart showing control of measures against condensed water according to the second embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First Embodiment)
The secondary battery manufacturing apparatus according to the first embodiment of the present invention will be described.

FIG. 1 is a schematic configuration diagram of the engine system 100 according to the first embodiment. The engine (internal combustion engine) 1 is mounted on a vehicle. The engine system 100 is provided with an intake passage 2 for sending intake air to the engine 1 and an exhaust passage 3 for passing exhaust gas from the engine 1.

In the intake passage 2, the compressor 4A of the turbocharger 4, the throttle valve 5, and the intercooler 6 are arranged in this order from the upstream side of the intake flow. Then, the intake air is supplied to the engine 1 via the branch path provided in the intake manifold 1A.

The throttle valve 5 is driven and controlled by a throttle motor. The air metered by the throttle valve 5 is cooled by the intercooler 6 and then distributed by the intake manifold 1A and flows into the three cylinders 1B. Air is sequentially introduced into each of the three cylinders 1B according to the firing order. The intercooler 6 is a water-cooled type, and the strength of cooling can be controlled by controlling the flow rate of water. Further, although FIG. 1 shows an example in which the number of cylinders is three, the present invention is not limited to this.

The fuel injection valve 7 is provided in the intake manifold 1A. By controlling the fuel injection valve 7 to open at a predetermined timing, fuel is injected into the intake manifold 1A, and a mixture of fuel and air is formed in the intake manifold 1A. Further, the cylinder 1B is provided with a spark plug (not shown), and the air-fuel mixture is burned using the spark plug. The fuel injection valve 7 may be provided in the cylinder 1B.

The combustion gas of the engine 1 is discharged to the exhaust passage 3 through the exhaust manifold 1C. In the exhaust passage 3, the turbine 4B of the turbocharger 4 and the three-way catalyst (hereinafter, also simply referred to as “catalyst”) 8 are arranged in order from the upstream side of the exhaust flow. The catalyst is not limited to a three-way catalyst and may be an oxidation catalyst.

The turbine 4B of the turbocharger 4 is rotated by exhaust energy. When the turbine 4B rotates, the compressor 4A provided coaxially with the turbine 4B also rotates. Then, the air introduced into the cylinder 1B is overpressurized.

In this embodiment, the case where the turbocharger 4 is used will be described, but the present invention is not limited to this. For example, it may be a mechanical or electric supercharger.

The engine system 100 further includes an exhaust gas recirculation passage (hereinafter, also referred to as “EGR passage”) 9 that connects the downstream side of the three-way catalyst 8 in the exhaust passage 3 and the upstream side of the compressor 4A in the intake passage 2. ing. In the EGR passage 9, an EGR cooler 10 for cooling the exhaust gas (EGR gas) flowing through the EGR passage 9 and an EGR valve 11 for controlling the exhaust flow flow through the EGR passage 9 are arranged. The EGR valve 11 is controlled by the controller 30. The EGR passage 9, the EGR cooler 10, and the EGR valve 11 are sometimes referred to as an "EGR device".

In the EGR device of the present embodiment, the EGR passage 9 connects the downstream of the three-way catalyst 8 in the exhaust passage 3 and the upstream of the compressor 4A in the intake passage 2. This corresponds to a so-called low pressure EGR device (hereinafter, also referred to as LP-EGR device).

In the intake passage 2, an air flow meter 21 for detecting the amount of air flowing into the intake passage 2 and the temperature is provided upstream of the junction with the EGR passage 9. Further, an intake oxygen concentration sensor 22 capable of detecting oxygen concentration is attached downstream of the compressor 4A and upstream of the throttle valve 5. A pressure sensor 23 is provided downstream of the intercooler 6. The pressure sensor 23 can measure the pressure of the intake air to the engine 1. The values detected by the air flow meter 21, the intake oxygen concentration sensor 22, and the pressure sensor 23 are transmitted to the controller 30, which is a control unit.

In the exhaust passage 3, a wide-area air-fuel ratio sensor 24 is provided upstream of the turbine 4B. Further, an exhaust oxygen concentration sensor 25 is provided downstream of the branching point to the EGR passage 9. The exhaust oxygen concentration sensor 25 can measure not only the oxygen concentration of the exhaust gas to the outside of the engine system 100 but also the temperature. The values detected by the wide area air-fuel ratio sensor 24 and the exhaust oxygen concentration sensor 25 are transmitted to the controller 30.

The controller 30 also accepts detection values of the crank angle sensor 26, the accelerator opening sensor 27, and the like. Based on these detected values, the controller 30 executes opening degree control of the throttle valve 5, opening degree control of the EGR valve 11, fuel injection control using the fuel injection valve 7, ignition timing control using the spark plug, and the like. To do. The controller 30 is composed of a microcomputer provided with a central arithmetic unit (CPU), a read-only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface). It is also possible to configure the controller 30 with a plurality of microcomputers.

The controller 30 performs EGR control for recirculating the EGR gas when the operating conditions of the engine 1 satisfy a predetermined EGR implementation condition.

First, the controller 30 calculates the EGR rate during intake from the oxygen concentration in the intake passage 2 detected by the intake oxygen concentration sensor 22. Specifically, when the intake oxygen concentration sensor 22 measures the oxygen concentration in the intake passage 2, the controller 30 calculates the actual EGR rate by using the oxygen concentration and a predetermined table. Then, the controller 30 feedback-controls the opening degree of the EGR valve 11 so that the calculated EGR rate matches the target EGR rate uniquely determined according to the operating conditions.

When the EGR gas is recirculated to the intake passage 2, it is necessary to increase the opening degree of the throttle valve 5 by the amount of the increase in the intake air by the EGR gas, so that the pumping loss due to the reciprocating movement of the piston is reduced and the fuel efficiency is improved. It is known to do. Further, when the EGR gas is recirculated to the intake passage 2, the combustion temperature of the air-fuel mixture in the cylinder 1B is lowered and the knocking resistance is improved, so that the ignition timing retardation amount for avoiding knocking is reduced. It is also known that fuel efficiency is improved.

In the present embodiment, the intake oxygen concentration sensor 22 is provided downstream of the compressor 4A and upstream of the throttle valve 5, but the present invention is not limited to this. Since the intake oxygen concentration sensor 22 is provided to obtain the actual EGR rate, it may be provided at any position downstream of the confluence with the EGR passage 9 in the intake passage 2.

Further, the controller 30 calculates the air-fuel ratio feedback correction coefficient based on the output of the wide-area air-fuel ratio sensor 24 so that the air-fuel ratio of the exhaust gas matches the target air-fuel ratio. Further, the controller 30 corrects the air-fuel ratio feedback correction coefficient based on the detected value of the exhaust oxygen concentration sensor 25. Then, the controller 30 feedback-controls the amount of fuel supplied from the fuel injection valve 7 by using the corrected air-fuel ratio feedback correction coefficient.

The reason for adopting the air-fuel ratio feedback control using two sensors (wide-area air-fuel ratio sensor 24 and exhaust oxygen concentration sensor 25) attached to the front and rear of the three-way catalyst 8 is as follows. The three-way catalyst 8 can efficiently purify all of HC, CO, and NOx only within a predetermined air-fuel ratio range (window) centered on the theoretical air-fuel ratio. Therefore, it is necessary for the controller 30 to prevent the air-fuel ratio before and after the three-way catalyst 8 from deviating from the window. Therefore, the air-fuel ratio is controlled by using the measured values of the wide-area air-fuel ratio sensor 24 and the exhaust oxygen concentration sensor 25. Since the measured values of the wide area air-fuel ratio sensor 24 and the exhaust oxygen concentration sensor 25 are substantially the same, the air-fuel ratio feedback control can be performed based only on the detected values of the wide area air-fuel ratio sensor 24.

Here, in the intercooler 6, the pressure is high due to the boost pressure, and the temperature is low because the intercooler 6 is cooled. In such a case, since the saturated vapor amount of the intake air decreases, condensed water is generated depending on the humidity of the intake air. If this condensed water is included in the intake air to the engine 1, the combustion performance of the engine may deteriorate.

In order to suppress the generation of condensed water, it is necessary to take measures against condensed water such as controlling the turbocharger 4 to lower the supercharging pressure or suppressing cooling by the intercooler 6 to raise the intake air temperature. It doesn't become. Such measures against condensed water will change the operating conditions of the engine 1. Therefore, there is a possibility that a desired output, fuel consumption, etc. cannot be obtained, and a surge may occur due to a change in the combustion state, which may lead to deterioration of riding comfort, and may deteriorate driving performance.

In the present embodiment, as shown below, it is determined whether or not the generated state of condensed water satisfies the permissible criteria, and measures against condensed water are taken based on the determination result. Therefore, as compared with the case where the condensed water countermeasure is taken when the generation of the condensed water is predicted, the frequency of implementing the condensed water countermeasure is low, so that the deterioration of the operating performance can be suppressed.

FIG. 2 is a diagram showing a flowchart of control of measures against condensed water performed by the controller 30.

In step S1, the controller 30 performs a parameter acquisition process. Specifically, the controller 30 acquires the detected value by each sensor.

In step S2, an estimation step of estimating the generation state of condensed water in the intercooler 6 is performed. Specifically, the controller 30 calculates the amount of condensed water generated Mw per unit time in the subsequent stage of the intercooler 6. More specifically, the difference between the amount of water vapor per unit volume in the front stage of the intercooler 6 and the amount of saturated water vapor in the rear stage of the intercooler 6 is obtained, and the difference is multiplied by the intake flow rate to generate the amount of condensed water per unit time. Mw can be calculated.

The amount of water vapor in the previous stage of the intercooler 6 can be obtained according to the oxygen concentration of the intake air measured by the intake oxygen concentration sensor 22. Further, the saturated water vapor amount in the subsequent stage of the intercooler 6 can be obtained from the intake pressure and the temperature. The intake pressure is detected by the pressure sensor 23. The intake air temperature can be calculated from the temperature measured by the air flow meter 21 based on the EGR rate, the operating rate of the intercooler 6, and the like. A temperature sensor may be provided at the same position as the pressure sensor 23, and the temperature of the intake air may be estimated by the temperature sensor.

The dew point temperature can be obtained from the vapor pressure of the intake air, and the amount of condensed water generated per unit time can be calculated by comparing the dew point temperature with the temperature downstream of the intercooler 6. The amount of condensed water generated can also be calculated by comparing the partial pressure of water vapor in the intake air with the saturated water vapor pressure.

In step S3, a reference step is performed in which an allowable standard for the state of generation of condensed water is determined. Specifically, the controller 30 calculates, as an allowable standard, the allowable upper limit threshold value Mc of the condensed water flowing into the engine 1 per unit time. The threshold value Mc is the inflow amount of condensed water per unit time that flows into the engine 1, and is the inflow amount when the deterioration of the operating performance of the engine 1 due to the inflow becomes unacceptable. Since the threshold value Mc changes according to the rotation speed and load of the engine 1, the controller 30 stores a map corresponding to the rotation speed and load and the threshold value Mc, and uses the map to set the threshold value Mc. calculate. Since the threshold value Mc is based on the combustion yield strength of the engine 1, a value obtained in advance by an experiment or the like is stored in the map.

In step S4, a determination step is performed, and it is determined whether or not the generated state of condensed water required in step S2 satisfies the permissible criteria determined in step S3. Specifically, the controller 30 determines whether or not the amount of condensed water generated Mw per unit time in the intercooler 6 is larger than the threshold value Mc. When the generated amount Mw is larger than the threshold value Mc (S4: Yes), the process proceeds to step S5 in order to implement the measures against condensed water. On the other hand, when the generated amount Mw is equal to or less than the threshold value Mc (S4: No), the treatment is terminated without taking measures against condensed water.

In step S5, the countermeasure step is executed, and the controller 30 implements the countermeasure against condensed water.

As an example of measures against condensed water, the controller 30 controls the EGR valve 11 to reduce the EGR rate, thereby reducing the amount of exhaust gas recirculation containing water. As the amount of exhaust gas recirculation decreases, the amount of condensed water generated decreases.

Further, as another example, the controller 30 lowers the operating rate by reducing the amount of water flowing through the intercooler 6. When the cooling of the intake air is suppressed, the amount of saturated water vapor increases as the temperature of the intake air rises, so that the amount of condensed water generated decreases.

As yet another example, the controller 30 reduces the boost pressure by opening a wastegate (not shown). Since the intake pressure decreases due to the decrease in the boost pressure, the saturated water vapor amount increases, and the amount of condensed water generated can be reduced.

In the present embodiment, the controller 30 executes the estimation step, the reference step, the determination step, and the countermeasure step, but the present invention is not limited to this. For example, the controller 30 includes an estimation unit that performs an estimation step, a reference unit that performs a reference step, a determination unit that performs a determination step, and a countermeasure unit that performs a countermeasure step, and these blocks execute each step. It may be configured to do so.

According to the first embodiment, the following effects can be obtained.

According to the first embodiment, the generation state of condensed water is estimated in the estimation step, and the permissible standard is set in the reference step. Then, in the determination step, when the estimated generated state of condensed water does not satisfy the permissible standard, measures against condensed water are implemented.

Specifically, as measures against condensed water, the EGR rate is lowered, the operating rate of the intercooler 6 is lowered, the intake pressure is lowered, and the like. A decrease in the EGR rate may worsen fuel efficiency, a decrease in the operating rate of the intercooler 6 may cause knocking, and a decrease in the intake pressure may cause a decrease in the operating rate of the engine 1.

However, in the present embodiment, since the determination step is performed, the condensed water countermeasure is taken when the generated state of the condensed water does not satisfy the permissible standard. Therefore, compared to the case where the condensed water countermeasures are always taken when the generation of condensed water is predicted, the frequency of implementing the condensed water countermeasures is suppressed, so that the deterioration of driving performance such as riding comfort and fuel consumption can be suppressed. it can.

According to the first embodiment, the generated state of the condensed water is the generated amount of the condensed water generated in the intercooler 6, and the permissible standard is the upper limit amount of the condensed water allowed to flow into the engine 1. In the engine 1, when the amount of condensed water generated is relatively small, even if the condensed water flows into the engine 1 together with the intake air, the combustion efficiency does not decrease. Therefore, when the predicted amount of condensed water generated is less than the permissible upper limit amount, the condensed water countermeasure is not taken, so that the deterioration of the operating performance can be suppressed.

(Second Embodiment)
In the first embodiment, the necessity of measures against condensed water was determined by using the amount of condensed water generated Mw per unit time. In the second embodiment, an example of determining the necessity of measures against condensed water by using the amount of accumulated condensed water in the subsequent stage of the intercooler 6 will be described.

If the condensed water accumulated in the intercooler 6 flows into the cylinder 1B at once, the engine 1 may misfire and the operating performance may deteriorate. However, if the amount of water flowing into the engine 1 at one time is not large, the influence on the operating performance of the engine 1 is small. Therefore, even if the condensed water is accumulated in the intercooler 6, it is not necessary to take measures against the condensed water immediately.

FIG. 3 is a diagram showing a flowchart of control of measures against condensed water using the amount of accumulated condensed water.

In this flowchart, as compared with the flowchart of the first embodiment shown in FIG. 2, steps S3 and S4 are deleted, and steps S11 to S13 are added.

In step S11, the controller 30 obtains the inflow amount Mf of the condensed water into the engine 1 per unit time. The inflow amount Mf is calculated based on the flow velocity of the intake air and the size and shape of the intake air passage 2. The intake flow rate can be obtained by dividing the intake flow rate according to the operating conditions of the engine 1 by the cross-sectional area of the intake passage 2. Further, the size and shape of the intake passage 2 are determined in advance by design. For example, when the intake passage 2 is arranged at a position lower than that of the engine 1, the inflow amount Mf that can flow into the engine 1 from the intake passage 2 becomes small.

In step S12, the controller 30 calculates the retention amount Ma per unit time of the condensed water. The amount of residence Ma per hour can be obtained by subtracting the amount of condensed water inflow Mf calculated in step S11 from the amount of condensed water generated Mw calculated in step S2.

In step S13, the controller 30 obtains the time integral value of the retention amount Ma per unit time as the retention amount of condensed water. Then, the controller 30 determines whether or not the integrated value of the retention amount exceeds the threshold value Mc2. The threshold value Mc2 is an upper limit value that can be tolerated as a retention amount, and is determined by the combustion yield strength of the engine 1 and the size and shape of the intake passage 2.

Then, when the integrated value of the retention amount exceeds the threshold value Mc2 (S13: Yes), measures against condensed water are implemented (S5). On the other hand, when the integrated value of the retention amount is equal to or less than the threshold value Mc2 (S13: No), the treatment is terminated without taking measures against condensed water.

The threshold Mc2 can be determined by various methods. As an example, the allowable amount of the engine 1 when all the accumulated condensed water flows into the engine 1 at one time can be set as the threshold value Mc2. As another example, the threshold value Mc2 may be set without assuming that all the accumulated condensed water flows into the engine 1 at one time. For example, depending on the shape of the pipe, all the accumulated condensed water may not flow into the engine 1 at once. Therefore, the threshold value Mc2 may be set in consideration of the ratio of the amount of condensed water that can flow into the engine 1 to the stagnant amount and the ratio to the allowable amount of the engine 1.

According to the second embodiment, the following effects can be obtained.

According to the second embodiment, the generated state of the condensed water is an integrated value of the generated amount of the condensed water generated in the intercooler 6. Further, the permissible standard is a value determined according to the permissible amount of the engine 1 in which the condensed water is allowed to flow into the engine 1 at one time.

The condensed water that stays in the subsequent stage of the intercooler 6 may enter the engine 1 at once due to vibration or the like. Even if the condensed water stays, if the amount of the condensed water staying does not exceed the permissible amount that can flow into the engine 1 at one time, it is not necessary to take measures against the condensed water. Therefore, when the accumulated amount of condensed water exceeds the permissible amount of the engine 1, taking measures against condensed water reduces the frequency of implementing measures against condensed water, so that deterioration of operating performance can be suppressed.

According to the second embodiment, the permissible standard is determined according to the ratio of the inflow amount of condensed water to the engine 1 to the stagnant amount in addition to the permissible amount of the engine 1. Depending on the shape of the intake pipe and the like, all the condensed water that stays in the subsequent stage of the intercooler 6 may not enter the engine 1 at once. Therefore, the permissible standard is determined according to the ratio of the inflow amount of the condensed water to the engine 1 to the condensate water in addition to the permissible amount of the engine 1. By doing so, the permissible standard can be lowered, so that the deterioration of the driving performance can be further suppressed.

According to the second embodiment, the controller 30 estimates the generated amount Mw of the condensed water generated per unit time in the intercooler 6, and estimates the inflow amount Mf of the condensed water flowing into the engine 1 per unit time. Then, the controller 30 estimates the retention amount Ma by subtracting the inflow amount Mf from the generated amount Mw and time-integrating the subtraction result. By doing so, the retention amount Ma can be estimated with high accuracy, so that the deterioration of the operating performance can be appropriately suppressed.

According to the second embodiment, the larger the intake flow rate, the larger the inflow amount Mf of the condensed water. Therefore, the intake flow rate is obtained according to the operating condition of the engine 1, and is based on the intake flow rate and the area of the intake passage 2. , The intake flow velocity is required. Then, the inflow amount Mf of the condensed water is determined based on the intake flow velocity. Further, the inflow amount Mf of the condensed water can be determined according to the shape of the intake pipe. By doing so, the estimation accuracy of the inflow amount Mf of the condensed water is improved, so that the estimation accuracy of the retention amount Ma is improved, and the deterioration of the operating performance can be appropriately suppressed.

According to the second embodiment, the amount of condensed water allowed to flow into the engine 1 at one time can be determined based on the combustion yield strength of the engine 1. The allowable amount of condensed water can also be determined by the shape of the pipe. In this way, since the amount of condensed water that is allowed to flow into the engine 1 at one time can be accurately determined, it is possible to appropriately suppress the deterioration of the operating performance.

Although the embodiments of the present invention have been described above, the above embodiments are only a part of the application examples of the present invention, and the technical scope of the present invention is limited to the specific configurations of the above embodiments. Absent. In addition, the above embodiments can be combined as appropriate.

1 Engine 2 Intake passage 3 Exhaust passage 5 Turbocharger 6 Intercooler 9 EGR passage 10 EGR cooler 11 EGR valve 30 Controller

Claims (5)

It is a control method for an engine equipped with an intercooler in the intake passage.
The amount of condensed water generated per unit time is estimated according to the operating condition of the engine, the amount of condensed water flowing into the engine per unit time is estimated, and the amount of inflow is subtracted from the amount generated. and, by integrating the result of subtraction time, and estimating step of estimating the occurrence of the condensed water in the intercooler,
The reference steps that determine the permissible criteria for the occurrence situation and
A determination step for determining whether or not the occurrence situation satisfies the permissible criteria, and
If the occurrence situation does not meet the permissible criteria, a countermeasure step for implementing condensate countermeasures is provided.
The occurrence state is the amount of the condensed water retained in the subsequent stage of the intercooler.
The permissible standard is an upper limit retention amount of the condensed water determined according to the amount of the condensed water allowed to flow into the engine at one time, and the upper limit retention amount is the rotation speed and load of the engine. It is an amount that is determined from the viewpoint of suppressing the deterioration of driving performance according to
In the determination step, it is determined whether or not the retention amount exceeds the upper limit retention amount.
In the countermeasure step, an engine control method for implementing the condensed water countermeasure when the retention amount exceeds the upper limit retention amount. The engine control method according to claim 1.
The engine control method, wherein the upper limit retention amount is further determined according to the ratio of the amount of condensed water that can flow into the engine at one time to the retention amount. The engine control method according to claim 2.
The inflow amount is determined by the intake flow velocity and the shape of the intake passage.
An engine control method in which the intake flow velocity is determined from an intake flow rate according to an operating condition of the engine and an area of the intake passage. The engine control method according to any one of claims 1 to 3.
An engine control method in which the amount of condensed water allowed to flow into the engine at one time is determined by the combustion yield strength of the engine and the shape of the intake passage. An engine equipped with an intake passage, an intercooler, and a controller.
The controller
The amount of condensed water generated per unit time is estimated according to the operating condition of the engine, the amount of condensed water flowing into the engine per unit time is estimated, and the amount of inflow is subtracted from the amount generated. and, by integrating the result of subtraction time, an estimation unit for estimating the occurrence of the condensed water in the intercooler,
The reference part that determines the permissible standard of the occurrence situation and
A determination unit that determines whether or not the occurrence status satisfies the permissible criteria,
If the occurrence situation does not meet the permissible criteria, a countermeasure unit that implements countermeasures against condensed water is provided.
The occurrence state is the amount of the condensed water retained in the subsequent stage of the intercooler.
The permissible standard is an upper limit retention amount of the condensed water determined according to the amount of the condensed water allowed to flow into the engine at one time, and the upper limit retention amount is the rotation speed and load of the engine. It is an amount that is determined from the viewpoint of suppressing the deterioration of driving performance according to
The determination unit determines whether or not the retention amount exceeds the upper limit retention amount, and determines whether or not the retention amount exceeds the upper limit retention amount.
The countermeasure unit is an engine that implements the condensed water countermeasure when the retention amount exceeds the upper limit retention amount.

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