JP2021001556A - Control device of vehicle and control method of vehicle - Google Patents

Abstract

To provide a control device of a vehicle which can properly collect water remaining in a water passage to a water tank while suppressing the lowering of a battery residual amount, and a control method, in the vehicle having the water passage for supplying water to a reforming catalyst.SOLUTION: A control device of a vehicle comprises: a reforming catalyst 1; a water tank 2; a water injection valve 3; a first water passage 4 for connecting the water tank 2 and the water injection valve 3; a water pump 5; a second water passage 6 branched from a branch part 4A of the first water passage 4 at the water injection valve 3 side rather than the water pump 5, and connected to the water tank 2; and an electromagnetic opening/closing valve 7 arranged at the second water passage 6. When a vehicle is brought into a non-traveling state, the electromagnetic opening/closing valve 7 is immediately valve-opened when a water temperature in the first water passage 4 is 100°C or higher, and water in the first water passage 4 is collected in the water tank 2 by using the decompression ebullition of residual water. On the other hand, when the water temperature is lower than 100°C, the electromagnetic opening/closing valve 7 is valve-opened after discharging the residual water from the water injection valve 3 for a prescribed time, and remaining water is collected in the water tank 2 by a fall by the dead weight of the water.SELECTED DRAWING: Figure 1

Description

The present invention relates to a control device and a control method for a vehicle provided with a reforming catalyst and a fuel reforming device having a passage for water supply.

As one of the technologies for improving the thermal efficiency of an internal combustion engine used in a vehicle such as an automobile, there is a technology for improving the ignitability of fuel by including hydrogen in the intake air supplied to the combustion chamber. As a method for including hydrogen in the intake air as described above, a means for chemically reacting gasoline fuel and water with a reforming catalyst for hydrogen generation by utilizing the heat of exhaust gas is known. In order to realize such means, the vehicle is provided with a reforming catalyst, a water tank for storing water supplied to the reforming catalyst, a water injection valve for injecting water into the reforming catalyst, and a water tank. A fuel reformer equipped with a water passage for supplying water to the water injection valve will be provided.

However, when a fuel reformer having such a configuration is adopted, the water remaining in the water passage connecting the water injection valve and the water tank freezes during parking (when the vehicle is stopped), especially in winter or in cold regions. There is a concern that water cannot be sprayed for a while during the next operation. Moreover, since the water passage is composed of a relatively thin pipe, it may be damaged by freezing. As a technique for dealing with such a problem, for example, in Patent Document 1 (Japanese Patent Laid-Open No. 2017-145700), an electric urea water pump is provided in order to prevent urea water from remaining in the urea water passage. A technique of reverse rotation and recovery in a urea water tank is disclosed.

JP-A-2017-145700

However, if an electric pump is used to recover the liquid remaining in the liquid passage as in the configuration disclosed in Patent Document 1, there is a concern that the remaining battery power will be reduced and the operation of other electrical components will be adversely affected. There is. Especially in winter and cold regions, it is desirable to be able to suppress the decrease in battery level while the vehicle is stopped as much as possible.

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to suppress a decrease in the remaining battery level of water in a vehicle provided with a water passage for supplying water to the reforming catalyst. It is an object of the present invention to provide a vehicle control device and a control method capable of appropriately recovering water remaining in a passage to a water tank.

In order to achieve the above object, the following solution is adopted in the present invention. That is, as described in claim 1, in the vehicle control device, the reforming catalyst for promoting the steam reforming reaction, the water injection valve for supplying water to the reforming catalyst, and the vertical direction of the vehicle. A water tank provided below the water injection valve, a first water passage connecting the water injection valve and the water tank, a water pump provided in the first water passage, and the first water passage. A second water passage branched from the water injection valve side of the water pump and connected to the water tank, an on-off valve provided in the second water passage, and the above when the vehicle is in a running state. While the on-off valve is closed, the control means for closing the on-off valve when the vehicle is in a non-running state is provided.

According to the above solution method, in the vehicle control device, when the vehicle is in a non-running state (stopped state), the on-off valve is opened and the second water passage is in a communicating state, so that the inside of the first water passage is entered. The water remaining in the water can be recovered in the water tank via the second water passage by utilizing decompression boiling or dropping by its own weight. That is, when the pressure in the first water passage is released to atmospheric pressure by opening the on-off valve, a part of the water in the first water passage (when the water temperature is 100 ° C. or higher) is steamed by decompression boiling. Since the first water passage is filled with water vapor, the liquid water in the first water passage is pushed out by this water vapor and flows into the lower water tank due to its own weight, and the first water passage is filled with water vapor. It is wiped out from the inside. Even if steam remains in the first water passage after the water is recovered by using such decompression boiling, the volume of the residual steam is reduced to about 1/1000 due to liquefaction, so that the residual steam is reduced to about 1/1000 in the first passage. Leaves only a very small amount of water. Therefore, since almost no water remains in the first water passage, it is possible to appropriately prevent the pipe from bursting due to freezing of the residual water, and at the next operation, water until the frozen water in the first water passage melts. There is no need to wait for injection, and the time until water injection becomes possible can be shortened. Further, for the discharge of water from the first water passage, decompression boiling of water in the first water passage and dropping due to its own weight are used, so that extra battery consumption is not required.

A preferred embodiment based on the above-mentioned solution method is as described in claims 2 and below in the scope of claims. That is, the water temperature sensor provided in the first water passage is provided, and the control means is in a running state when the water temperature in the first water passage detected by the water temperature sensor is less than 100 ° C. After opening the water injection valve for a predetermined time with the on-off valve closed, the water injection valve is closed and the on-off valve is opened (claimed). Corresponding to item 2). In this case, if the water temperature in the first water passage is less than 100 ° C., water cannot be expected to be discharged from the first water passage using vacuum boiling. Therefore, the water injection valve is first opened and the first is 1 After discharging a part of water through the water injection valve using the high pressure in the water passage, the on-off valve is opened, and the water remaining in the first water passage is dropped by its own weight to the second. Drain through the water passage. Therefore, the water in the first water passage is properly discharged even when the temperature is not higher than 100 ° C. Further, for the discharge of water from the first water passage, injection from the water injection valve using the pressure of the water in the first water passage and dropping by the own weight of the water are used, so that an extra battery is used. No consumption is required.

Further, as described in claim 3, a reforming catalyst for promoting the steam reforming reaction, a water injection valve for supplying water to the reforming catalyst, and water provided below the water injection valve. From the tank, the first water passage connecting the water injection valve and the water tank, the water pump provided in the first water passage, and the water injection valve side of the first water passage from the water pump side. In a vehicle control method for controlling a vehicle having a second water passage branched and connected to the water tank and an on-off valve provided in the second water passage, when the vehicle is in a running state, the said The on-off valve is closed, while the on-off valve is opened when the vehicle is in a non-running state.

According to the above solution method, in the vehicle control method, when the vehicle is in a non-running state, the on-off valve is opened and the second water passage is in a communicating state, so that the water remaining in the first water passage Can be recovered in a water tank via the second water passage by utilizing decompression boiling or dropping by its own weight. That is, when the pressure in the first water passage is released to atmospheric pressure by opening the on-off valve, a part of the water in the first water passage (when the water temperature is 100 ° C. or higher) is steamed by decompression boiling. Since the first water passage is filled with water vapor, the liquid water in the first water passage is pushed out by this water vapor and flows into the lower water tank due to its own weight, and the first water passage is filled with water vapor. It is wiped out from the inside. Even if steam remains in the first water passage after the water is recovered by using such decompression boiling, the volume of the residual steam is reduced to about 1/1000 due to liquefaction, so that the residual steam is reduced to about 1/1000 in the first passage. Leaves only a very small amount of water. Therefore, since almost no water remains in the first water passage, it is possible to appropriately prevent the pipe from bursting due to freezing of the residual water, and at the next operation, water until the frozen water in the first water passage melts. There is no need to wait for injection, and the time until water injection becomes possible can be shortened. Further, for the discharge of water from the first water passage, decompression boiling of water in the first water passage and dropping due to its own weight are used, so that extra battery consumption is not required.

A preferred embodiment based on the above-mentioned solution method is as described in claims 4 and below in the scope of claims. That is, the vehicle is provided with a water temperature sensor provided in the first water passage, and when the water temperature in the first water passage detected by the water temperature sensor is less than 100 ° C., the vehicle is in a running state. When the non-running state is reached, the water injection valve is opened for a predetermined time with the on-off valve closed, and then the water injection valve is closed and the on-off valve is opened (claim). 4 correspondence). In this case, in this case, if the water temperature in the first water passage is less than 100 ° C., water cannot be expected to be discharged from the first water passage using vacuum boiling, so the water injection valve is first opened. Then, after discharging a part of water through the water injection valve using the high pressure in the first water passage, the on-off valve is opened and the water remaining in the first water passage is dropped by its own weight. It is discharged through the second water passage. Therefore, the water in the first water passage is properly discharged even when the temperature is not higher than 100 ° C. Further, for the discharge of water from the first water passage, injection from the water injection valve using the pressure of the water in the first water passage and dropping by the own weight of the water are used, so that an extra battery is used. No consumption is required.

According to the present invention, the residual water can be appropriately removed from the water passage that supplies water to the reforming catalyst, so that the residual water in the water passage freezes in the non-running state of the vehicle, which causes damage to the pipeline. There is no such thing as a delay in starting the next fuel reformer (starting water supply).

The figure which shows an example of the structure of the vehicle provided with the control device of this invention. The flowchart which shows an example of the control of this invention.

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

FIG. 1 shows an example of the configuration of a vehicle equipped with the control device of the present invention. As shown in the figure, the vehicle is provided with a fuel reformer including a reforming catalyst (reformer) 1 and a water tank 2. The reforming catalyst 1 is provided with a water injection valve 3, and water from the water tank 2 is supplied to the reforming catalyst 1 via the water injection valve 3. As a result, hydrogen is generated by the chemical reaction between the reforming catalyst 1 and water, and the fuel gas (reforming gas) containing hydrogen is supplied to the engine E.

The reforming catalyst 1 is a catalyst for promoting the steam reforming reaction, and is arranged on the exhaust gas passage 10 of the engine E. As a result, the reforming catalyst 1 is given the heat of the exhaust gas flowing through the exhaust gas passage 10 via the heat exchange mechanism (not shown), and the reforming catalyst 1 has a temperature suitable for a chemical reaction with water. It is designed to warm up to (active temperature).

The water tank 2 and the water injection valve 3 are connected by a first water passage 4. A water pump 5 is provided at a predetermined position of the first water passage 4, and the water in the water tank 2 is pumped up to the water injection valve 3 by the water pump 5. The water pressure in the first water passage 4 rises to, for example, 1 to 25 MPa as a result of being sucked up by the water pump 5. Further, the water pump 5 is an electric pump, and its drive is controlled by the controller U.

The second water passage 6 branches from the branch portion 4A on the water injection valve 3 side (downstream side when viewed from the water tank 2) of the water pump 5 of the first water passage 4, and the second water passage 6 Connects the branch portion 4A and the water tank 2. Further, the second water passage 6 is provided with an electromagnetic on-off valve 7, and the flow of water through the second water passage 6 is permitted or prohibited by opening and closing the electromagnetic on-off valve 7. The opening and closing of the electromagnetic on-off valve 7 is controlled by the controller U.

The first water passage 4 is connected to a heat exchanger 8 arranged on the exhaust gas passage 10 at a predetermined position between the branch portion 4A and the water injection valve 3, and the first water passage 4 is connected via the heat exchanger 8. The heat of the exhaust gas flowing through the exhaust gas passage 10 is applied to the water flowing through the first water passage 4. As a result, the water downstream of the heat exchanger 11 in the first water passage 4 (water supplied to the water injection valve 3) is in a state of being heated to, for example, 100 to 200 ° C.

The return passage 11 also branches from the branch portion 4A of the first water passage 4 and reaches the inside of the water tank 2. The return passage 11 is provided with a flow rate adjusting valve 12 and a regulator 13. Further, the return passage 11 communicates with the portion downstream of the heat exchanger of the first water passage 4 via the communication passage 14 in the portion between the flow rate adjusting valve 12 and the regulator 13. The connecting passage 14 is provided with a check valve 15 that allows only the flow from the first water passage 4 to the return passage 11.

The first water passage 4 is provided with a first temperature sensor 21 arranged immediately in front of the water injection valve 3, so that the first temperature sensor 21 detects the water temperature in the first water passage 4. It has become. Further, the water tank 2 is provided with a second temperature sensor 22 that detects the water temperature of the stored tank water. The detected values of the first temperature sensor 21 and the second temperature sensor 22 are input to the controller U.

The controller U is, for example, a control device (engine control unit: PCM) configured by using a microcomputer, and is connected to an accessory power supply 23 (ACC). The controller U of the electromagnetic on-off valve 7 and the water injection valve 3 according to the water temperature detected by the first temperature sensor 21 so that the water remaining in the first water passage 4 is appropriately discharged when the vehicle is stopped. It functions as a control means for controlling opening and closing.

More specifically, when it is detected that the vehicle is in a non-running state (a state in which the engine E is stopped and the accessory power is turned off), that is, a stopped state, the controller U first detects it by the first temperature sensor 21. It is determined whether or not the water temperature in the first water passage 4 is 100 ° C. or higher, and if the water temperature in the first water passage 4 is 100 ° C. or higher, the electromagnetic on-off valve 7 is immediately opened. .. As the detected value of the first temperature sensor 21, the value detected immediately before the vehicle is stopped or immediately after the vehicle is stopped is used.

When the electromagnetic on-off valve 7 is opened in this way, the first water passage 4 communicates with the water tank 2 via the second water passage 6, and the pressure in the first water passage 4, which was high pressure, becomes water. Since the water is released to the pressure (atmospheric pressure) of the tank 2, the water remaining in the first water passage 4 is boiled under reduced pressure. As a result, the first water passage 4 is filled with steam generated by decompression boiling, and the water in the first water passage 4 (water in a liquid state without boiling) is pushed out by the steam and becomes water. It is discharged into the tank 2 and cleared from the first water passage 4. Further, even if water vapor remains in the first water passage 4 after the residual water is discharged, the volume is reduced to about 1/1000 when the water vapor is liquefied, and as a result, an extremely small amount is contained in the first water passage 4. Only water remains. Therefore, almost all the residual water is appropriately discharged from the first water passage 4.

On the other hand, when the water temperature in the first water passage 4 detected by the first temperature sensor 21 is not 100 ° C. or higher, it cannot be expected to utilize the reduced pressure boiling of the residual water in the first water passage 4, so that the controller U temporarily opens the water injection valve 3 for a predetermined time with the electromagnetic on-off valve 7 closed. As a result, a part of the water in the first water passage 4 is discharged from the water injection valve 3 due to the high pressure in the first water passage 4. After a certain amount of water is discharged by the injection from the water injection valve 3 over such a predetermined time, the water injection valve 3 is closed and the electromagnetic on-off valve 7 is opened. The water remaining in the passage 4 is collected in the water tank 2 through the second water passage 6 by dropping due to its own weight. Therefore, even when the water temperature in the first water passage 4 is relatively low, the water in the first water passage 4 is discharged by combining the discharge from the water injection valve 3 and the discharge from the second water passage. Almost no residual water can be left in the first water passage 4.

As described above, according to the vehicle control device of the present embodiment, the residual water in the first water passage 4 is substantially completely discharged by an appropriate method according to the temperature in the first water passage 4. Therefore, even in the extremely cold state where the water freezes, the water remaining in the first water passage 4 freezes when the vehicle is stopped, and the first water passage 4, which is a relatively narrow pipeline, is damaged. Etc. will not occur. Further, when the fuel reformer is used next time, it is not necessary to wait for the frozen water in the first water passage 4 to thaw, so that the water is immediately supplied to the reforming catalyst 1 using the first water passage 4. Can be started. Further, for such discharge of water from the first water passage 4, decompression boiling of water in the first water passage 4, dropping due to its own weight, and discharge from the water injection valve 3 due to high pressure are used. It doesn't consume extra battery.

Next, an example of the control procedure of the present invention will be described with reference to the flowchart of FIG. In the control, first, in step S1, it is determined whether or not the vehicle is in a non-driving state (engine E is stopped, accessory power supply 23 is off), and if it is not in a non-driving state, the process proceeds to step S2 for control. The mode is set to the control during normal operation (the electromagnetic on-off valve 7 is closed), and the entire processing cycle is completed.

If it is determined in step S1 that the vehicle is in a non-running state, the process proceeds to step S3, and the temperature (water temperature) in the first water passage 4 detected by the first temperature sensor 21 is 100 ° C. or higher. If it is determined whether or not the temperature is 100 ° C. or higher, the process proceeds to step S7. In step S7, the electromagnetic on-off valve 7 is opened to allow the first water passage 4 and the water tank 2 to communicate with each other via the second water passage 6, and then the one-round processing cycle is completed.

In this way, when the temperature of the first water passage 4 is 100 ° C. or higher, the electromagnetic on-off valve 7 is immediately opened, and the pressure in the first water passage 4 is changed to the pressure (atmospheric pressure) of the water tank 2. By opening the water, the water remaining in the first water passage 4 is boiled under reduced pressure, and the steam generated thereby wipes out the residual water in the first water passage 4.

On the other hand, if the temperature in the first water passage 4 is not 100 ° C. or higher in the determination in step 3, the process proceeds to step S4 and the water injection valve 3 is opened (with the electromagnetic on-off valve 7 still closed). .. In the following step S5, it is determined whether or not the predetermined time has elapsed, and this determination is repeated until the predetermined time elapses. When the predetermined time has elapsed, the process proceeds to step S6, the water injection valve 3 is closed, the process proceeds to step S7, the electromagnetic on-off valve 7 is opened, and the one-round processing cycle is completed.

As described above, when the temperature in the first water passage 4 is less than 100 ° C. and the reduced pressure boiling cannot be used, the water injection valve 3 is once opened for a predetermined time to generate water from the water injection valve 3. The electromagnetic on-off valve 7 is opened to discharge the remaining water from the second water passage 6. Thereby, even when the temperature in the first water passage 4 is relatively low, the residual water in the first water passage 4 can be appropriately removed.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and appropriate modifications can be made within the scope of the claims.

The present invention can be used in a vehicle equipped with a fuel reforming device that generates a reforming gas by a chemical reaction between a reforming catalyst and water.

E engine U controller 1 reforming catalyst (reformer)
2 Water tank 3 Water injection valve 4 1st water passage 4A branch 5 Water pump 6 2nd water passage 7 Electromagnetic on-off valve 8 Heat exchanger 10 Exhaust gas passage 11 Return passage 12 Flow control valve 13 Regulator 14 Communication passage 15 Check valve Valve 21 1st temperature sensor 22 2nd temperature sensor 23 Accessory power supply

Claims (4)

In the vehicle control device
A reforming catalyst for promoting the steam reforming reaction,
A water injection valve that supplies water to the reforming catalyst,
A water tank provided below the water injection valve in the vertical direction of the vehicle,
A first water passage connecting the water injection valve and the water tank,
The water pump provided in the first water passage and
A second water passage branched from the water injection valve side of the first water passage and connected to the water tank.
An on-off valve provided in the second water passage and
A vehicle control device including a control means for closing the on-off valve when the vehicle is in a running state and closing the on-off valve when the vehicle is in a non-running state. In the vehicle control device according to claim 1,
A water temperature sensor provided in the first water passage is provided.
When the water temperature in the first water passage detected by the water temperature sensor is less than 100 ° C., the control means closes the on-off valve when the vehicle changes from a running state to a non-running state. A vehicle control device that closes the water injection valve and opens the on-off valve after opening the water injection valve for a predetermined time in this state. A reforming catalyst for promoting the steam reforming reaction,
A water injection valve that supplies water to the reforming catalyst,
A water tank provided below the water injection valve and
A first water passage connecting the water injection valve and the water tank,
The water pump provided in the first water passage and
A second water passage branched from the water injection valve side of the first water passage and connected to the water tank.
In a vehicle control method for controlling a vehicle provided with an on-off valve provided in the second water passage.
A vehicle control method in which the on-off valve is closed when the vehicle is running, while the on-off valve is opened when the vehicle is not running. In the vehicle control method according to claim 3,
The vehicle includes a water temperature sensor provided in the first water passage.
When the water temperature in the first water passage detected by the water temperature sensor is less than 100 ° C., when the vehicle changes from a running state to a non-running state, the on-off valve is closed for a predetermined time. A method for controlling a vehicle in which the water injection valve is closed and then the on-off valve is opened after the water injection valve is opened.

Images