JP2023087869A - Intake air cooling device for vehicle - Google Patents

Abstract

To provide an intake air cooling device for a vehicle capable of preventing generation of condensation water in intake air and boiling of cooling water even when an outside air temperature fluctuates.SOLUTION: An intake air cooling device for a vehicle includes: an intercooler 10 for cooling intake air introduced to an engine body 1 by using cooling water; cooling water amount adjustment means 32, 33 capable of adjusting a cooling water supply flow rate that is a flow rate of the cooling water to be supplied to the intercooler 10; control means 90 for controlling the cooling water amount adjustment means 32, 33 to control an actual intake air temperature that is a temperature of intake air derived from the intercooler 10 to a target intake air temperature; and an outside air temperature sensor SN4 for detecting an outside air temperature. The control means 90 corrects the target intake air temperature in accordance with the outside air temperature detected by the outside air temperature sensor SN4, and when the outside air temperature is high, sets a higher target intake air temperature, than when the outside air temperature is low.SELECTED DRAWING: Figure 1

Description

The present invention relates to an intake air cooling device for a vehicle on which an engine body and a radiator are mounted.

A vehicle may be provided with an intercooler for cooling intake air introduced into an engine body. The intercooler cools the intake air by exchanging heat between the cooling water supplied from the outside and the intake air.

Here, if the intake air is excessively cooled by the intercooler, condensed water is generated in the intake air. If the condensed water is introduced into the engine body, it is not preferable because misfiring or the like may occur.

As a prior art for solving this problem, for example, in a control device for an internal combustion engine described in Patent Document 1, by controlling a water pump so that the temperature of intake air at the outlet of an intercooler reaches a predetermined target intake air temperature, It suppresses the generation of condensed water in the intercooler. Further, the control device controls the water pump to increase the amount of cooling water when the intake air temperature at the outlet of the intercooler continues to be higher than the target air temperature, thereby suppressing boiling of the cooling water.

Japanese Patent Application Laid-Open No. 2017-115828

However, when the outside air temperature is high, the amount of moisture contained in the air is generally large. Even if the control is performed so that the amount of condensed water in the intake air cooled in the intercooler increases, there is a risk of misfiring or other problems.

On the other hand, if the same target intake air temperature is set when the outside air temperature is low as when the outside air temperature is high, the amount of cooling water supplied to the intercooler decreases, and the cooling water tends to boil. There is a risk.

SUMMARY OF THE INVENTION The present invention has been made in view of the circumstances described above, and provides an intake air cooling system for a vehicle that can suppress the generation of condensed water in the intake air and the boiling of cooling water even if the outside air temperature fluctuates. aim.

In order to solve the above-mentioned problems, an intake air cooling system for a vehicle according to the present invention includes an intercooler for cooling intake air introduced into an engine body with cooling water, and cooling water, which is the flow rate of the cooling water supplied to the intercooler. cooling water amount adjusting means capable of adjusting a supply flow rate; control means for controlling the cooling water amount adjusting means to adjust an actual intake air temperature, which is the temperature of the intake air derived from the intercooler, to a target intake air temperature; The control means corrects the target intake air temperature according to the outside air temperature detected by the outside air temperature sensor, and corrects the target intake air temperature when the outside air temperature is high with respect to when the outside air temperature is low. The temperature is set high.

According to this configuration, the control means corrects the target intake air temperature according to the outside air temperature, in response to the tendency that the amount of moisture in the air increases when the outside air temperature is high. Specifically, by setting the target intake air temperature relatively high when the outside air temperature is high, the control means can suppress an increase in the amount of condensed water in the intake air, which tends to increase when the outside air temperature is high. be. Also, by setting the target intake air temperature relatively low when the outside air temperature is low, it is possible to prevent the amount of cooling water supplied to the intercooler from dropping excessively as the outside air temperature drops, thereby preventing the boiling of the cooling water. can be suppressed. Therefore, with the above configuration, it is possible to suppress the generation of condensed water in the intake air and the boiling of the cooling water even if the outside air temperature fluctuates.

In the vehicle intake air cooling system described above, the cooling water amount adjusting means includes a water pump that pumps the cooling water to the intercooler, and the control means controls the temperature of the cooling water supplied to the intercooler, the Based on the temperature of the intake air introduced into the intercooler and the flow rate of the intake air passing through the intercooler, an amount of cooling water required to maintain the actual intake air temperature at the target intake air temperature is set, and It is preferable to control the water pump so as to pump the cooling water with the amount of cooling water.

According to such a configuration, the control means controls the water pump based on the temperature of the cooling water supplied to the intercooler, the temperature of the intake air on the introduction side of the intercooler, and the flow rate of the intake air, so that the intercooler is led out. It is possible to accurately adjust the amount of cooling water so that the amount of cooling water required to maintain the actual intake air temperature on the side at the target intake air temperature.

In the above intake air cooling device for a vehicle, the cooling water amount adjusting means further includes a flow rate adjusting valve for adjusting the opening degree of the cooling water passage through which the cooling water flows, and the control means controls the actual intake air temperature and the target intake air temperature. Preferably, the flow control valve is controlled based on the difference from the temperature.

According to this configuration, the amount of cooling water is derived from the intercooler in the operating state in which the control means controls the water pump so that the amount of cooling water is the amount necessary to maintain the target intake air temperature. Even if there is a difference between the actual intake air temperature and the target intake air temperature, the control means controls the flow control valve based on the difference between the actual intake air temperature and the target intake air temperature to adjust the opening of the cooling water passage. By adjusting , it is possible to finely adjust the amount of cooling water. As a result, it is possible to more accurately adjust the amount of cooling water so that the amount of cooling water is required to maintain the target intake air temperature.

In the intake air cooling system for a vehicle, the control means preferably controls the cooling water amount adjusting means so as to increase the amount of cooling water when the temperature of the cooling water drawn out from the intercooler exceeds the boiling point.

With such a configuration, it is possible to increase the amount of cooling water when the temperature of the cooling water drawn out from the intercooler exceeds the boiling point, thereby preventing boiling of the cooling water.

In the above intake air cooling system for a vehicle, the control means controls the first cooling water flow rate, which is the cooling water supply flow rate required to bring the temperature of the intake air drawn from the intercooler to a predetermined target intake air temperature. and a second cooling water flow rate that is the minimum value of the cooling water supply flow rate required to make the temperature of the cooling water in the intercooler less than a predetermined cooling water upper limit temperature. a second calculation unit that compares the calculated first cooling water flow rate and the second cooling water flow rate, and if the first cooling water flow rate is equal to or greater than the second cooling water flow rate, the The cooling water amount adjusting means is controlled based on the first cooling water flow rate, and when the first cooling water flow rate is less than the second cooling water flow rate, the cooling water amount adjusting means is controlled based on the second cooling water flow rate. preferably.

By performing the above control, boiling of the cooling water can be reliably prevented. That is, when the first cooling water flow rate is equal to or higher than the second cooling water flow rate, that is, even if the cooling water flow rate introduced into the intercooler is set to the first cooling water flow rate, the temperature of the cooling water in the intercooler If the temperature is considered to be below the upper limit temperature, the cooling water amount adjusting means is controlled based on the first cooling water flow rate. Therefore, the cooling water temperature is kept below the cooling water upper limit temperature to suppress boiling of the cooling water in the intercooler, and the actual intake air temperature, which is the temperature of the intake air drawn from the intercooler, is adjusted to the target intake air temperature. The cooling water amount adjusting means can be controlled. Further, when the first cooling water flow rate is less than the second cooling water flow rate and the cooling water flow rate introduced into the intercooler is set to the first cooling water flow rate, the temperature of the cooling water in the intercooler is equal to or higher than the cooling water upper limit temperature. , the cooling water amount adjusting means is controlled based on the second cooling water flow rate. Therefore, even in this case, it is possible to prevent the temperature in the intercooler from exceeding the upper limit temperature of the cooling water, thereby suppressing boiling of the cooling water in the intercooler. As a result, boiling of cooling water in the intercooler can be reliably suppressed, and damage to the intercooler can be prevented.

In the above intake air cooling device for a vehicle, it is preferable that the intercooler is of a facing type in which the direction in which the cooling water flows in the intercooler is opposite to the direction in which the intake air flows.

Since the intercooler is of a facing type in which the direction in which cooling water flows and the direction in which intake air flows in the intercooler are opposite to each other, heat can be efficiently exchanged between the cooling water and the intake air. In addition, even in the case of a facing type intercooler in which the cooling water is susceptible to heat from the intake air, the target intake air temperature is set low according to the outside air temperature when the outside air temperature is low as described above. Boiling of cooling water is also suppressed.

In the above intake air cooling system for a vehicle, the control means is arranged such that when the outside air temperature is equal to or higher than a predetermined reference temperature, the rate of change of the target intake air temperature with respect to the outside air temperature becomes greater than when the outside air temperature is lower than the reference temperature. It is preferable to set the target intake air temperature to

With such a configuration, the control means sets the target intake air temperature such that when the outside air temperature is equal to or higher than the predetermined reference temperature, the rate of change of the target intake air temperature with respect to the outside air temperature is greater than when the outside air temperature is lower than the reference temperature. As a result, when the outside air temperature is equal to or higher than the predetermined reference temperature and the amount of moisture in the air is large, priority is given to suppressing an increase in the amount of condensed water in the intake air, and the rate of change of the target intake air temperature with respect to the outside air temperature is increased. It becomes possible to let On the other hand, when the outside air temperature is lower than the predetermined reference temperature, it is possible to reduce the rate of change by giving priority to suppressing boiling of the cooling water caused by reducing the amount of cooling water supplied to the intercooler. become. As a result, both an increase in the amount of condensed water in the intake air and boiling can be effectively suppressed.

As described above, according to the present invention, it is possible to provide an intake air cooling system for a vehicle that can suppress the generation of condensed water in the intake air and boiling of cooling water even if the outside air temperature fluctuates.

1 is a system diagram showing an intake air cooling device for a vehicle according to an embodiment of the present invention; FIG. 1 is a schematic diagram showing a vehicle front portion; FIG. It is a schematic block diagram of an intercooler. It is a control block of the intake air cooling device according to the present embodiment. 4 is a flow chart showing a procedure for controlling the flow rate of cooling water according to the embodiment; 4 is a graph showing changes in target intake air temperature with respect to outside air temperature; (a) shows the relationship between the inlet gas temperature and the first cooling water flow rate, (b) shows the relationship between the cooling water temperature and the first cooling water flow rate, and (c) shows the relationship between the intake air amount and the first cooling water flow rate. is a graph showing. (a) shows the relationship between the inlet gas temperature and the second cooling water flow rate, (b) shows the relationship between the cooling water temperature and the second cooling water flow rate, and (c) shows the relationship between the intake air amount and the second cooling water flow rate. is a graph showing.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an intake air cooling device for a vehicle according to an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing an intake air cooling system A1 and an engine system A2 in a vehicle equipped with an intake air cooling device for a vehicle according to the present embodiment of the invention.

As shown in FIG. 1, the engine system A2 includes an engine body 1 in which cylinders are formed, an intake passage 2 that introduces intake air into the engine body 1, an exhaust passage 3 that guides exhaust gas from the engine body 1, and an EGR device 4 . In this embodiment, the vehicle V on which the intake air cooling system A1 and the engine system A2 are installed is a hybrid vehicle, and has an electric motor (not shown) in addition to the engine main body 1 as a driving source of the vehicle V.

The intake passage 2 is provided with a compressor 5a of a supercharger 5 that supercharges intake air, and an intercooler 10 that is provided downstream of the compressor 5a in the intake passage 2 and cools the intake air. . The intake passage 2 is also provided with an airflow sensor SN1 for detecting the flow rate of intake air and an intake air temperature sensor SN2 for detecting the temperature of the intake air. The airflow sensor SN1 is provided in a portion of the intake passage 2 upstream of a connecting portion of the compressor 5a and an EGR passage 4a, which will be described later. The intake air temperature sensor SN2 is provided between the compressor 5a in the intake passage 2 and the intercooler 10, and detects the temperature of the intake air before being introduced into the intercooler 10.

In addition, the outside air temperature is detected at a position near the inlet for introducing the outside air and the air filter (not shown) in the intake passage 2 of the present embodiment (that is, the position on the upstream side of the air flow sensor SN1 in FIG. 1). An outside air temperature sensor SN4 is provided.

A turbine 5 b of a supercharger 5 is provided in the exhaust passage 3 . The turbocharger 5 supercharges the intake air by receiving the energy of the exhaust gas and rotating the turbine 5b, which drives the compressor 5a to rotate. A purifier 6 for purifying the exhaust gas is provided in the exhaust passage 3 downstream of the turbine 5b.

The EGR device 4 includes an EGR passage 4a that communicates the exhaust passage 3 and the intake passage 2 to recirculate the exhaust gas to the intake passage 2, and an EGR cooler 4b that cools the EGR gas that is the exhaust gas that flows through the EGR passage 4a. , and an EGR valve 4c capable of opening and closing the EGR passage 4a. The EGR passage 4a communicates a portion of the exhaust passage 3 downstream of the turbine 5b and a portion of the intake passage 2 upstream of the compressor 5a.

The intake air cooling system A1 includes a cooling water circuit 20 in which cooling water flows (circulates), a grill shutter 50, a radiator 31 provided on the cooling water circuit 20, an electric water pump 32, a flow rate adjustment valve 33, It has HEV equipment 40 and ATF cooler (ATF/C) 41 . The intercooler 10 is also provided on the cooling water circuit 20, and the intercooler 10 is also a component of the intake air cooling system A1. That is, the intercooler 10 is supplied with cooling water flowing through the cooling water circuit 20, and the intercooler 10 cools the intake air by heat exchange between the cooling water and the intake air. Further, the cooling water circuit 20 is provided with a water temperature sensor SN3 for detecting the temperature of the cooling water flowing through it. The water temperature sensor SN3 is provided between the radiator 31 and the water pump 32 in the cooling water circuit 20 and detects the temperature of the cooling water immediately after it is led out from the radiator 31 .

The radiator 31 is a device for cooling the coolant flowing through the coolant circuit 20 . As shown in FIG. 2, the radiator 31 is provided in front of the engine body 1 in the front part of the vehicle V, and cools the cooling water by receiving running wind. The water pump 32 is a pump for pumping cooling water. The water pump 32 is provided downstream of the radiator 31 in the cooling water circuit 20 . The HEV device 40 is an electric device mounted on the vehicle V as the vehicle is a hybrid vehicle, and includes an electric motor, a converter, and the like. The ATF cooler 41 is a device for cooling AT oil supplied to a transmission provided in the vehicle.

The cooling water circuit 20 branches into a first cooling water passage 21 and a second cooling water passage 22 at a branch portion 20 a downstream of the water pump 32 . An intercooler 10 is arranged in the first cooling water passage 21 . An HEV device 40 and an ATF cooler 41 are provided in this order from the upstream side in the second cooling water passage 22 . The downstream end of the first cooling water passage 21 and the downstream end of the second cooling water passage 22 join at a confluence portion 20 b on the upstream side of the radiator 31 in the cooling water circuit 20 . From this, the basic flow of cooling water in the cooling water circuit 20 is as follows. The cooling water drawn out from the radiator 31 first branches into the first cooling water passage 21 and the second cooling water passage 22 at the branch portion 20a. The cooling water that has flowed into the first cooling water passage 21 cools the intake air in the intercooler 10 . On the other hand, the cooling water flowing into the second cooling water passage 22 cools the HEV equipment 40 and then cools the AT oil in the ATF cooler 41 . The cooling water that has passed through the intercooler 10 and the cooling water that has passed through the HEV equipment 40 and the ATF cooler 41 merge at the confluence portion 20b, are introduced again into the radiator 31, and are cooled by the radiator 31. .

A flow control valve 33 for opening and closing the first cooling water passage 21 is provided in the first cooling water passage 21 . When the flow control valve 33 is closed, the cooling water is stopped from flowing into the first cooling water passage 21 and the intercooler 10 .

FIG. 3 is a schematic cross-sectional view of the intercooler 10. As shown in FIG. The intercooler 10 includes an intake air introduction portion 11 through which intake air is introduced, an intake air outlet portion 12 through which the intake air is led out, a cooling water inlet portion 15 through which cooling water is introduced, and a cooling water outlet portion through which cooling water is led out. 16. As shown in FIG. 3, in this embodiment, the intercooler 10 is of a facing type, and is configured such that the direction in which cooling water flows and the direction in which intake air flows in the intercooler are opposed to each other. That is, in the intercooler 10 shown in FIG. 3, the cooling water lead-out portion 16 is provided in the upstream portion with respect to the flow direction of the intake air (the direction of the arrow Y1 in FIG. 3), and the cooling water lead-in portion 15 is provided in the downstream portion. is provided. As indicated by an arrow Y2, the cooling water in the intercooler 10 flows from the downstream side to the upstream side with respect to the flow direction of the intake air. A cooling water supply flow rate, which is the flow rate of cooling water supplied to the intercooler 10 , is changed by the rotation speed of the water pump 32 and the opening degree of the flow control valve 33 . As described above, in this embodiment, the cooling water supply flow rate, which is the flow rate of the cooling water supplied from the radiator 31 to the intercooler 10, is changed according to the rotational speed of the water pump 32 and the opening degree of the flow control valve 33. , and the water pump 32 and the flow control valve 33 correspond to the "cooling water amount control means" in the claims.

As shown in FIG. 2 , the grille shutter 50 is provided between a front grille 301 provided at the front of the vehicle V and the radiator 31 . The grille shutter 50 has a plurality of vertically arranged flaps 51 and a driving device (not shown) for rotating the flaps. The grille shutter 50 is switched between an open state as indicated by the solid line in FIG. 2 and a closed state as indicated by the chain line in FIG. 2 by rotating the flap 51 by the driving device. When the grille shutter 50 is closed, the flow of wind directed toward the radiator 31 from the front is cut off, and the cooling power of the radiator 31 by running wind and the cooling power of the cooling water by the radiator 31 are weakened.

Here, the intake air cooling device 60 for a vehicle of the present invention includes at least the intake air cooling system A1, the grille shutter 50, and an ECU 90 which will be described later.

(control configuration)
FIG. 4 is a block diagram showing control configurations of the intake air cooling system A1 and the engine system A2. The vehicle V is equipped with an ECU (engine control module) 90, which is a control means for controlling each part of the vehicle V. As shown in FIG. The ECU 90 is a microprocessor comprising a CPU, ROM, RAM and the like.

The ECU 90 receives detection signals from various sensors mounted on the vehicle V, such as the airflow sensor SN1, the intake air temperature sensor SN2, the water temperature sensor SN3, and the outside air temperature sensor SN4. The ECU 90 controls each part of the vehicle 100 while executing various determinations and calculations based on input signals from these sensors SN1 to SN4. The ECU 90 is electrically connected to the water pump 32, the flow control valve 33, the grill shutter 50, the EGR valve 4c, and the like, and outputs control signals to these devices based on the results of the above calculations. For example, the ECU 90 opens the EGR valve 4 c in order to recirculate the EGR gas to the intake passage 2 in the entire operating range of the engine body 1 .

In the ECU 90, functionally, a first calculation unit 91 for calculating a first cooling water flow rate (to be described later), a second calculation unit 92 for calculating a second cooling water flow rate (to be described later), and a target intake air temperature (to be described later) are set. A target intake air temperature setting unit 93 is provided.

(cooling water flow rate control)
The cooling water flow rate control performed by the ECU 90 will be described with reference to the flowchart of FIG.

First, in step S1, the ECU 90 reads the detection values and the like of each sensor. The ECU 90 reads at least the detected values of the airflow sensor SN1, the intake air temperature sensor SN2, the water temperature sensor SN3, and the outside air temperature sensor SN4. Hereinafter, the flow rate of the intake air detected by the airflow sensor SN1 will be referred to as the intake air amount, and the temperature of the intake air detected by the intake air temperature sensor SN2 and before being introduced into the intercooler 10 will be referred to as the intake gas temperature. The temperature of the cooling water detected by the water temperature sensor SN3, which is the temperature of the cooling water immediately after it is led out from the radiator 31, is called the cooling water temperature. is called the ambient temperature.

Next, in step S2, the ECU 90 sets a target intake air temperature according to the outside air temperature. Specifically, the target intake air temperature setting unit 93 of the ECU 90 responds to a certain outside air temperature TA based on correspondence data in which the target intake air temperature TG with respect to the outside air temperature TA is set in advance, as shown in the graph of FIG. One target intake air temperature TG is set. The correspondence data is stored in the memory of the ECU 90 .

Here, the target intake air temperature is the temperature of the intake air in the intake air lead-out portion 12 of the intercooler 10, which is the temperature of the intake air after being cooled by the intercooler 10 (hereinafter referred to as the actual intake air temperature or exit gas temperature as appropriate). is the target value of

The actual intake air temperature is calculated by the ECU 90 based on, for example, the temperature of cooling water supplied to the intercooler 10, the temperature of the intake air introduced into the intercooler 10, and the flow rate of the intake air passing through the intercooler 10. can get. Alternatively, when a temperature sensor is provided in the section between the intercooler 10 and the engine body 1 in the intake passage 2, the temperature sensor may directly detect the actual intake air temperature.

Here, as shown in the graph of FIG. 6, the ECU 90 determines that the rate of change of the target intake air temperature TG with respect to the outside air temperature TA is higher when the outside air temperature TA is equal to or higher than a predetermined reference temperature .theta.A than when the outside air temperature TA is below the reference temperature .theta.A. It is preferable to set the target intake air temperature TG such that . As a result, both an increase in the amount of condensed water in the intake air and boiling can be effectively suppressed. As the reference temperature θA, for example, a general environmental temperature (approximately 25° C.) or a slightly higher temperature is adopted.

Next, in step S3, the ECU 90 calculates the first cooling water flow rate. The first cooling water flow rate is the cooling water required to bring the actual intake air temperature (outgoing gas temperature), which is the temperature of the intake air on the lead-out side of the intercooler 10, to the target intake air temperature set in step S2. is the supply flow rate. That is, the first cooling water flow rate is the flow rate of cooling water to be supplied to the intercooler 10 so that the temperature of the intake air supercharged by the compressor 5a and raised to a high temperature is lowered by the intercooler 10 to the target intake air temperature.

The ECU 90 calculates the first cooling water flow rate based on the incoming gas temperature, the cooling water temperature, and the intake air amount read in step S1. In order to lower the actual intake air temperature (outgoing gas temperature) to the target intake air temperature, it is necessary to increase the flow rate of cooling water introduced into the intercooler 10 as the incoming gas temperature increases. In response to this, the ECU 90 calculates a larger value for the first cooling water flow rate as the incoming gas temperature increases, as shown in FIG. 7(a). Further, in order to lower the actual intake air temperature to the target intake air temperature, it is necessary to increase the flow rate of the cooling water introduced into the intercooler 10 as the cooling water temperature increases. In response to this, the ECU 90 calculates a larger value for the first cooling water flow rate as the cooling water temperature increases, as shown in FIG. 7(b). In addition, in order to lower the actual intake air temperature to the target intake air temperature, it is necessary to increase the flow rate of the cooling water introduced into the intercooler 10 as the amount of intake air increases. In response to this, the ECU 90 calculates a larger value for the first cooling water flow rate as the intake air amount increases, as shown in FIG. 7(c).

The ECU 90 of this embodiment controls the water pump 32 and the flow control valve 33, which are means for adjusting the amount of cooling water, so as to increase the amount of cooling water when the temperature of the cooling water drawn from the intercooler 10 exceeds the boiling point. Specifically, control is performed according to the procedure of steps S4 to S10 below.

First, in step S4, the ECU 90 calculates the second cooling water flow rate. The second cooling water flow rate is the cooling water supply flow rate (intercooler 10 introduction is the minimum value of the cooling water flow rate that should be used. Specifically, in the intercooler 10, the temperature of the intake air is higher toward the upstream side (with respect to the flow direction of the intake air). As a result, the temperature of the cooling water in the intercooler 10 becomes highest at the upstream end of the intercooler 10 in the flow direction of the intake air, that is, at the cooling water lead-out portion 16 . The second cooling water flow rate is the temperature of the cooling water in the cooling water lead-out portion 16 and is the minimum value of the cooling water supply flow rate required to make the temperature of the cooling water in the intercooler 10 less than the cooling water upper limit temperature. be. It should be noted that the greater the flow rate of cooling water flowing through the intercooler 10, the smaller the temperature rise of the cooling water due to the heat received from the intake air.

The cooling water upper limit temperature is preset and stored in the ECU 90 . The cooling water upper limit temperature is set to a temperature (such as 100° C.) that is substantially the same as the boiling point of the cooling water, and the second cooling water flow rate is the temperature required to keep the temperature of the cooling water in the intercooler 10 below the boiling point. This is the minimum value of the cooling water supply flow rate.

The ECU 90 calculates the second cooling water flow rate based on the incoming gas temperature, the cooling water temperature, and the intake air amount read in step S1. Since the temperature of the cooling water in the intercooler 10 tends to increase as the incoming gas temperature rises, in order to keep the intercooler water temperature below the cooling water upper limit temperature, the higher the incoming gas temperature, the more It is necessary to increase the flow rate of the cooling water to be used. In response to this, the ECU 90 calculates a larger value for the second cooling water flow rate as the incoming gas temperature increases, as shown in FIG. 8(a). Further, in order to keep the water temperature in the intercooler below the upper limit temperature of the cooling water, it is necessary to increase the flow rate of the cooling water introduced into the intercooler 10 as the cooling water temperature increases. In response to this, the ECU 90 calculates a larger value for the second cooling water flow rate as the cooling water temperature increases, as shown in FIG. 8(b). Also, in order to keep the water temperature in the intercooler below the upper limit temperature of the cooling water, it is necessary to increase the flow rate of the cooling water introduced into the intercooler 10 as the amount of intake air increases and the amount of heat radiation from the intake air to the cooling water increases. . In response to this, the ECU 90 calculates a larger value for the second cooling water flow rate as the intake air amount increases, as shown in FIG. 8(c).

After step S4, the ECU 90 calculates the second target cooling water amount in step S5. The second target cooling water amount is a target value for the flow rate of cooling water that flows through the second cooling water passage 22 and is supplied to the HEV device 40 and the ATF cooler 41 . The ECU 90 calculates the second target cooling water amount based on the temperature of the AT oil, the temperature of the HEV device 40, and the like.

After step S5, in step S6, the ECU 90 determines whether or not the first cooling water flow rate calculated in step S2 is greater than or equal to the second cooling water flow rate calculated in step S4. If the determination is YES and the first cooling water flow rate is greater than or equal to the second cooling water flow rate, the ECU 90 performs the process of step S7. In step S7, the ECU 90 sets the first target coolant flow rate to the first coolant flow rate. The first target cooling water amount is a target value for the flow rate of the cooling water that flows through the first cooling water passage 21 .

That is, the first cooling water flow rate is equal to or higher than the second cooling water flow rate, and the cooling water supply flow rate required to bring the actual intake air temperature (exhaust gas temperature) to the target intake air temperature is less than the intercooler internal water temperature. If the intercooler water temperature is equal to or higher than the cooling water supply flow rate necessary to lower the intercooler temperature below the temperature, and the intercooler water temperature can be lowered to the cooling water upper limit temperature or less even if the cooling water supply flow rate is set to the first cooling water flow rate, the first cooling water flow rate is the first cooling water flow rate. 1 is set to the target cooling water amount.

On the other hand, if the determination in step S6 is NO and the first cooling water flow rate is less than the second cooling water flow rate, the ECU 90 sets the second cooling water flow rate to the first target cooling water flow rate in step S8. That is, the first cooling water flow rate is less than the second cooling water flow rate, and the cooling water supply flow rate required to bring the actual intake air temperature to the target intake air temperature is required to bring the intercooler internal water temperature to the cooling water upper limit temperature or less. If the cooling water supply flow rate is less than the required cooling water flow rate and the water temperature in the intercooler cannot be lowered below the cooling water upper limit temperature even if the cooling water supply flow rate is set to the first cooling water flow rate, the second cooling water flow rate is set to the first target cooling water flow rate. be done.

After step S7 or step S8, the process proceeds to step S9. In step S9, the ECU 90 determines the rotation speed of the water pump 32 based on the set first target cooling water amount and second target cooling water amount. That is, the ECU 90 determines that the flow rate of cooling water flowing through the first cooling water passage 21 reaches the first target cooling water flow rate and that the flow rate of cooling water flowing through the second cooling water passage 22 and supplied to the intercooler 10 is is the second target cooling water amount. Then, the ECU 90 controls the water pump 32 so that the determined rotation speed is achieved.

After step S9, in step S10, the ECU 90 controls the flow rate adjustment valve 33 based on the actual intake air temperature, which is the temperature of the intake air on the lead-out side of the intercooler 10, and the first target cooling water amount and the second target cooling water amount. to determine the degree of opening of the Specifically, the ECU 90 controls the flow rate adjustment valve 33 based on the difference between the target intake air temperature and the actual intake air temperature derived from the intercooler 10 and the first target cooling water amount and the second target cooling water amount. Determine the degree of opening. For example, when the difference between the actual intake air temperature and the target intake air temperature is 0 or a positive value, basically the opening of the flow control valve 33 is set to 100% (fully open). On the other hand, when the actual intake air temperature is less than the target intake air temperature, that is, when the difference between the actual intake air temperature and the target intake air temperature is a negative value, the opening of the flow control valve 33 is basically set to 0%. Set to (fully closed). In addition to the above conditions, the opening degree of the flow control valve 33 may be appropriately changed based on the first target cooling water amount and the second target cooling water amount.

Thus, in the present embodiment, when the first cooling water flow rate is greater than or equal to the second cooling water flow rate, as in steps S6 to S8 above, the flow rate of the cooling water supplied to the intercooler 10 is reduced to the first cooling water flow rate. When the first cooling water flow rate is less than the second cooling water flow rate, the cooling water flow rate supplied to the intercooler 10 is the second cooling water flow rate. However, if the flow rate of the cooling water supplied to the intercooler 10 is simply set to the second cooling water flow rate when the first cooling water flow rate is less than the second cooling water flow rate, the actual intake air temperature will be higher than the target intake air temperature. As it becomes lower, condensed water is likely to be generated in the intake air. Specifically, the intake air contains water vapor in the air or in the EGR gas, which may condense.

Here, it is mainly when the temperature of the cooling water supplied to the intercooler 10 is low that condensed water tends to form in the intake air. Accordingly, when the cooling water temperature is low, the ECU 90 closes the grill shutter 50 to increase the temperature of the cooling water supplied to the intercooler 10 . As described above, when the grille shutter 50 is closed, the cooling power of the radiator 31 is weakened and the temperature of the cooling water is increased.

Specifically, in step S11 following step S10, the ECU 90 determines whether or not the cooling water temperature is equal to or higher than a predetermined determination water temperature, or whether or not the first cooling water flow rate is equal to or higher than the second cooling water flow rate. judge. The determination water temperature is a cooling water temperature at which condensed water is likely to occur during intake air, and is preset and stored in the ECU 90 . The judgment water temperature is set to about 40° C., for example.

If the determination in step S11 is YES and the cooling water temperature is equal to or higher than the judgment water temperature, or if the first cooling water flow rate is equal to or higher than the second cooling water flow rate, the ECU 90 opens the grill shutter 50 in step S12. Open (if already open, continue to open grille shutter 50). On the other hand, if the determination in step S11 is NO, the cooling water temperature is less than the determination water temperature, and the first cooling water flow rate is less than the second cooling water flow rate, the ECU 90 closes the grill shutter 50 in step S13. Close (continue to open grille shutter 50 if already open). After step S12 or step S13, the process returns to step S1.

In this way, the grille shutter 50 is closed only when the cooling water temperature is less than the judgment water temperature, the actual intake air temperature is less than the target intake air temperature, and the possibility of condensed water being generated in the intake air is higher. It will be. Therefore, it is possible to reliably suppress the generation of condensed water in the intake air, and prevent the cooling water from being excessively heated when the grille shutter 50 is closed.

(action, etc.)
In the vehicle intake air cooling system of the present embodiment configured as described above, the ECU 90 sets the target intake air temperature according to the outside air temperature in response to the tendency that the moisture content in the air increases when the outside air temperature is high. Correct (see step S2 in FIG. 5 and the graph in FIG. 6). Specifically, when the outside air temperature is high, the ECU 90 sets the target intake air temperature relatively higher than when the outside air temperature is low. can be suppressed. Further, when the outside air temperature is low, the target intake air temperature is set relatively lower than when the outside air temperature is high, thereby preventing the amount of cooling water supplied to the intercooler 10 from excessively decreasing as the outside air temperature drops. can be prevented, and boiling of the cooling water can be suppressed. Therefore, with the above configuration, it is possible to suppress the generation of condensed water in the intake air and the boiling of the cooling water even if the outside air temperature fluctuates.

Further, in the present embodiment, the cooling water amount adjusting means includes a water pump 32 that pumps the cooling water to the intercooler 10 . The ECU 90 maintains the actual intake air temperature at the target intake air temperature based on the temperature of the cooling water supplied to the intercooler 10, the temperature of the intake air introduced into the intercooler 10, and the flow rate of the intake air passing through the intercooler 10. The amount of cooling water required for this is set, and the water pump 32 is controlled to pump the cooling water at that amount.

According to this configuration, the ECU 90 controls the water pump 32 based on the temperature of the cooling water supplied to the intercooler 10, the temperature of the intake air on the introduction side of the intercooler 10, and the flow rate of the intake air. It is possible to accurately adjust the amount of cooling water so that the amount of cooling water required to maintain the actual intake air temperature on the outlet side of 10 at the target intake air temperature.

Moreover, in this embodiment, the cooling water amount adjusting means further includes a flow rate adjusting valve 33 that adjusts the opening degree of the cooling water passage through which the cooling water flows. The ECU 90 controls the flow control valve 33 based on the difference between the actual intake air temperature and the target intake air temperature.

According to this configuration, in the operating state where the water pump 32 is controlled by the ECU 90 so that the amount of cooling water is the amount of cooling water required to maintain the target intake air temperature, Even if there is a difference between the actual intake air temperature and the target intake air temperature, the ECU 90 controls the flow control valve 33 based on the difference between the actual intake air temperature and the target intake air temperature to open the cooling water passage. By adjusting the degree, it is possible to finely adjust the amount of cooling water. As a result, it is possible to more accurately adjust the amount of cooling water so that the amount of cooling water is required to maintain the target intake air temperature.

Further, in the present embodiment, the ECU 90 controls the cooling water amount adjusting means (the water pump 32 and the flow rate adjusting valve 33) so as to increase the cooling water amount when the temperature of the cooling water derived from the intercooler 10 exceeds the boiling point. to control. This makes it possible to increase the amount of cooling water when the temperature of the cooling water drawn out from the intercooler 10 exceeds the boiling point, thereby preventing boiling of the cooling water.

As a specific configuration for preventing boiling of the cooling water, in the present embodiment, the ECU 90 controls the first cooling water supply flow rate, which is the cooling water supply flow rate required to bring the temperature of the intake air derived from the intercooler 10 to a predetermined target intake air temperature. A first calculation unit 91 that calculates the water flow rate, and a second cooling water flow rate that is the minimum value of the cooling water supply flow rate required to make the temperature of the cooling water in the intercooler 10 less than the predetermined cooling water upper limit temperature. and a second calculator 92 for calculating. Comparing the calculated first cooling water flow rate and second cooling water flow rate, if the first cooling water flow rate is equal to or greater than the second cooling water flow rate, the cooling water amount adjusting means is based on the first cooling water flow rate. The water pump 32 and the flow rate adjusting valve 33 are controlled, and when the first cooling water flow rate is less than the second cooling water flow rate, the cooling water rate adjusting means (the water pump 32 and the flow rate adjusting valve 33).

By performing the above control, boiling of the cooling water can be reliably prevented. That is, when the first cooling water flow rate is equal to or higher than the second cooling water flow rate, that is, even if the cooling water flow rate introduced into the intercooler 10 is the first cooling water flow rate, the temperature of the cooling water in the intercooler 10 is When it is thought that the cooling water upper limit temperature will be exceeded, the cooling water amount adjusting means is controlled based on the first cooling water flow rate. Therefore, the temperature of the coolant is kept below the coolant upper limit temperature to suppress boiling of the coolant in the intercooler 10, and the actual intake air temperature, which is the temperature of the intake air drawn out from the intercooler 10, becomes the target intake air temperature. Thus, the cooling water amount adjusting means (the water pump 32 and the flow rate adjusting valve 33) can be controlled. Further, when the first cooling water flow rate is less than the second cooling water flow rate and the flow rate of the cooling water introduced into the intercooler 10 is set to the first cooling water flow rate, the temperature of the cooling water in the intercooler 10 reaches the cooling water upper limit. If the temperature is considered to be higher than the temperature, the cooling water amount adjusting means is controlled based on the second cooling water flow rate. Therefore, even in this case, the temperature in intercooler 10 can be prevented from exceeding the coolant upper limit temperature, and boiling of the coolant in intercooler 10 can be suppressed. As a result, boiling of cooling water in the intercooler 10 can be reliably suppressed, and damage to the intercooler 10 can be prevented.

Moreover, when the cooling water temperature is lower than the judgment water temperature and there is a high possibility that the intake air is excessively cooled by the cooling water in the intercooler 10 and condensed water is generated in the intake air, the grille shutter 50 is closed to cool the intake air. Water is heated. Therefore, even when the cooling water amount adjusting means is controlled based on the second cooling water flow rate, excessive cooling of the intake air by the cooling water and generation of condensed water can be suppressed.

In particular, in the present embodiment, while suppressing boiling of the cooling water in the intercooler 10 by adjusting the flow rate of the cooling water introduced into the intercooler 10, condensed water in the intake air accompanying this suppression of boiling of the cooling water is suppressed by closing the grille shutter 50 . As a result, it is not necessary to reduce the ratio of EGR gas introduced into the intake air in order to suppress the generation of condensed water in the intake air while suppressing the boiling of the cooling water, or the reduction amount can be reduced. Therefore, according to the present embodiment, boiling of cooling water in the intercooler 10 and generation of condensed water in the intake air can be suppressed while suppressing deterioration of exhaust gas performance.

In this embodiment, the intercooler 10 is of a facing type in which the cooling water flowing direction and the intake air flowing direction in the intercooler 10 are opposed to each other, so heat can be exchanged efficiently between the cooling water and the intake air. Also, even with the facing type intercooler 10 in which the cooling water is likely to receive heat from the intake air, the target intake air temperature is set low according to the outside air temperature when the outside air temperature is low as described above. , the boiling of the cooling water is also suppressed.

In the present embodiment, the ECU 90 sets the target intake air temperature such that when the outside air temperature is equal to or higher than a predetermined reference temperature, the rate of change of the target intake air temperature with respect to the outside air temperature is greater than when the outside air temperature is lower than the reference temperature. As a result, when the outside air temperature is equal to or higher than the predetermined reference temperature and the amount of moisture in the air is large, priority is given to suppressing an increase in the amount of condensed water in the intake air, and the rate of change of the target intake air temperature with respect to the outside air temperature is increased. It becomes possible to let On the other hand, when the outside air temperature is lower than the predetermined reference temperature, it is possible to reduce the rate of change by giving priority to suppressing boiling of the cooling water caused by reducing the amount of cooling water supplied to the intercooler 10. be possible. As a result, both an increase in the amount of condensed water in the intake air and boiling can be effectively suppressed.

Reference Signs List 1 engine body 2 intake passage 10 intercooler 20 cooling water circuit 31 radiator 32 water pump (flow rate adjusting means)
33 flow control valve (flow control means)
50 grille shutter 90 ECU (control means)
91 First calculator 92 Second calculator 93 Target intake air temperature setting unit

Claims (7)

an intercooler that cools the intake air introduced into the engine body with cooling water;
Cooling water amount adjusting means capable of adjusting a cooling water supply flow rate, which is the flow rate of the cooling water supplied to the intercooler;
a control means for controlling the cooling water amount adjusting means to adjust an actual intake air temperature, which is the temperature of the intake air derived from the intercooler, to a target intake air temperature;
and an outside air temperature sensor that detects the outside air temperature,
The control means corrects the target intake air temperature according to the outside air temperature detected by the outside air temperature sensor, and sets the target intake air temperature higher when the outside air temperature is high than when the outside air temperature is low. air intake cooling system for vehicles that In the intake air cooling device for a vehicle according to claim 1,
The cooling water amount adjusting means includes a water pump that pumps the cooling water to the intercooler,
The control means controls the actual intake air temperature based on the temperature of the cooling water supplied to the intercooler, the temperature of the intake air introduced into the intercooler, and the flow rate of the intake air passing through the intercooler. and setting a cooling water amount necessary to maintain the target intake air temperature, and controlling the water pump to pump the cooling water at the cooling water amount. In the intake air cooling device for a vehicle according to claim 2,
The cooling water amount adjusting means further includes a flow rate adjusting valve that adjusts the opening degree of the cooling water passage through which the cooling water flows,
The intake air cooling device for a vehicle, wherein the control means controls the flow control valve based on the difference between the actual intake air temperature and the target intake air temperature. In the intake air cooling device for a vehicle according to any one of claims 1 to 3,
The intake air cooling device for a vehicle, wherein the control means controls the cooling water amount adjusting means so as to increase the amount of cooling water when the temperature of the cooling water drawn out from the intercooler exceeds the boiling point. In the intake air cooling device for a vehicle according to claim 4,
The control means is
a first calculation unit for calculating a first cooling water flow rate, which is the cooling water supply flow rate required to bring the temperature of the intake air derived from the intercooler to a predetermined target intake air temperature;
A second calculation unit that calculates a second cooling water flow rate that is the minimum value of the cooling water supply flow rate required to make the temperature of the cooling water in the intercooler less than a predetermined cooling water upper limit temperature,
By comparing the calculated first cooling water flow rate and the second cooling water flow rate, if the first cooling water flow rate is equal to or greater than the second cooling water flow rate, the A vehicle characterized by controlling cooling water amount adjusting means, and controlling the cooling water amount adjusting means based on the second cooling water flow rate when the first cooling water flow rate is less than the second cooling water flow rate. air intake cooling system. In the intake air cooling device for a vehicle according to any one of claims 1 to 5,
An intake air cooling device for a vehicle, wherein the intercooler is of a facing type in which the direction in which the cooling water flows and the direction in which the intake air flows in the intercooler are opposite to each other. In the intake air cooling device for a vehicle according to any one of claims 1 to 6,
The control means sets the target intake air temperature such that when the outside air temperature is equal to or higher than a predetermined reference temperature, the rate of change of the target intake air temperature with respect to the outside air temperature is greater than when the outside air temperature is lower than the reference temperature. , an intake air cooling device for a vehicle.

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