US-12626935-B2 - Residual water drain system and method of fuel cell vehicle

US12626935B2US 12626935 B2US12626935 B2US 12626935B2US-12626935-B2

Abstract

An embodiment residual water drain system of a fuel cell vehicle includes a fuel cell, a drain device configured to drain residual water from the fuel cell, and a controller configured to drain the residual water from the fuel cell through the drain device, to turn off the fuel cell, and to convert a vehicle into an EV mode, when charging the vehicle with hydrogen is determined to be necessary.

Inventors

Dong Kwan Lee
Seon Hak KIM
Seung Hwan Lee

Assignees

HYUNDAI MOTOR COMPANY
KIA CORPORATION

Dates

Publication Date: 20260512
Application Date: 20221109
Priority Date: 20220609

Claims (20)

1 . A residual water drain system of a fuel cell vehicle, the system comprising: a fuel cell; a drain device configured to drain residual water from the fuel cell; and a controller programmed to: determine that charging the vehicle with hydrogen is necessary; cause the residual water to be drained from the fuel cell through the drain device and turn off the fuel cell in response to charging the vehicle with hydrogen being determined to be necessary; and convert the fuel cell vehicle into an EV mode in response to the residual water being drained from the fuel cell and the fuel cell being turned off.
2 . The system of claim 1 , wherein the drain device comprises an air compressor connected to the fuel cell and configured to drain the residual water from the fuel cell by supplying air to the fuel cell.
3 . The system of claim 1 , wherein: the drain device comprises an air compressor configured to supply air to the fuel cell; and the controller is programmed to operate the drain device in a normal drain condition or an emergency drain condition, wherein the air compressor has a greater number of revolutions or a higher supply air flow rate when operating in the emergency drain condition than when operating in the normal drain condition.
4 . The system of claim 3 , further comprising an information receiver configured to receive information from a navigation device, wherein the controller is programmed to drain the residual water from the fuel cell by operating the drain device before the vehicle is charged with hydrogen using navigation information received from the information receiver.
5 . The system of claim 4 , wherein, when the navigation information is unavailable, the controller is programmed to operate the drain device in the normal drain condition during a residual water drain time and then convert the vehicle into the EV mode, in response to a vehicle water drain request being input.
6 . The system of claim 5 , wherein the residual water drain time is a time taken for draining all of the residual water from the fuel cell by operating the drain device.
7 . The system of claim 5 , wherein, while the vehicle is operating in the EV mode, the controller is programmed to periodically review a state of charge of a battery and, when the state of charge of the battery is lower than a minimum state of charge, the controller is programmed to end the EV mode and convert the vehicle into a fuel cell start mode.
8 . The system of claim 4 , wherein the controller is programmed to review a destination of the vehicle when the navigation information is available and calculate an estimated travel time required to arrive at a hydrogen charging station when the destination of the vehicle is the hydrogen charging station.
9 . The system of claim 8 , wherein: the estimated travel time is a time period required to arrive at the destination from a current position of the vehicle; and the controller is programmed to update the estimated travel time according to the current position of the vehicle.
10 . The system of claim 8 , wherein, when the estimated travel time is shorter than a residual water drain time, the controller is programmed to limit an operating voltage of the fuel cell so as to not exceed a reference voltage and to operate the drain device in the emergency drain condition.
11 . The system of claim 8 , wherein: when the estimated travel time is longer than a residual water drain time and shorter than a first reference time, the controller is programmed to update the estimated travel time; and when the updated estimated travel time reaches an EV mode drivable time based on a current state of charge of a battery of the vehicle, the controller is programmed to operate the drain device in the normal drain condition during the residual water drain time.
12 . The system of claim 8 , wherein: when the estimated travel time is longer than a first reference time, the controller is programmed to update the estimated travel time; and when the updated estimated travel time reaches the first reference time, the controller is programmed to charge a battery by increasing a target state of charge of the battery.
13 . The system of claim 12 , wherein: when a state of charge of the battery reaches the target state of charge, the controller is programmed to update the updated estimated travel time to a second updated estimated travel time; and when the second updated estimated travel time reaches a second reference time shorter than the first reference time, the controller is programmed to operate the drain device in the normal drain condition during a residual water drain time.
14 . The system of claim 13 , wherein: while the vehicle is operating in the EV mode after the residual water is drained from the fuel cell, the controller is programmed to calculate an estimated discharge time based on the state of charge of the battery; and when the estimated discharge time is shorter than the second updated estimated travel time, the controller is programmed to limit an output of the vehicle.
15 . The system of claim 8 , wherein: when the navigation information is available but the destination of the vehicle is not the hydrogen charging station, the controller is programmed to review whether or not there is any hydrogen charging station recorded as a visited place within a reference radius of the vehicle or on a travel route leading to the destination; and when there is the hydrogen charging station recorded as the visited place, the controller is programmed to review whether or not a residual water drain preceding request is input.
16 . The system of claim 15 , wherein: when the residual water drain preceding request is input, the controller is programmed to calculate the estimated travel time required to arrive at the destination; and when the estimated travel time reaches a first reference time, the controller is programmed to charge a battery by increasing a target state of charge of the battery.
17 . A fuel cell vehicle, the vehicle comprising: a fuel cell; a drain device configured to drain residual water from the fuel cell; and a controller programmed to: determine that a destination of the vehicle is a hydrogen charging station based on information from a navigation device; calculate an estimated travel time required to arrive at the hydrogen charging station; update the estimated travel time as the vehicle travels to the hydrogen charging station in response to the estimated travel time being longer than a first reference time; charge a battery by increasing a target state of charge of the battery in response to the updated estimated travel time reaching the first reference time; cause the residual water to be drained from the fuel cell by operating the drain device while charging the battery; turn off the fuel cell in response to the residual water being drained from the fuel cell; and convert the vehicle into an EV mode in response to the residual water being drained from the fuel cell and the fuel cell being turned off.
18 . The vehicle of claim 17 , wherein the controller is further programmed to: update the updated estimated travel time to a second updated estimated travel time in response to a state of charge of the battery reaching the target state of charge; operate the drain device in a normal drain condition during a residual water drain time in response to the second updated estimated travel time reaching a second reference time shorter than the first reference time; calculate an estimated discharge time based on the state of charge of the battery in response to the vehicle operating in the EV mode after the residual water is drained from the fuel cell; and limit an output of the vehicle in response to the estimated discharge time being shorter than the second updated estimated travel time.
19 . A system of a fuel cell vehicle, the system comprising: a fuel cell; a drain device configured to drain residual water from the fuel cell; and a controller programmed to: determine that charging the vehicle with hydrogen is necessary; cause the residual water to be drained from the fuel cell through the drain device in response to determining that charging the vehicle with hydrogen is necessary; turn off the fuel cell in response to the residual water being drained from the fuel cell; convert the fuel cell vehicle into an EV mode in response to the fuel cell being turned off; and operate the vehicle in the EV mode by driving a motor using electricity stored in a battery.
20 . The system of claim 19 , wherein: the drain device comprises an air compressor configured to supply air to the fuel cell; and the controller is programmed to operate the drain device in a normal drain condition or an emergency drain condition, wherein the air compressor has a greater number of revolutions or a higher supply air flow rate when operating in the emergency drain condition than in the normal drain condition.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of Korean Patent Application No. 10-2022-0070036, filed on Jun. 9, 2022, which application is hereby incorporated herein by reference. TECHNICAL FIELD The present disclosure relates generally to a residual water drain system and method of a fuel cell vehicle. BACKGROUND In general, fuel cells generate electric energy through a chemical reaction between hydrogen serving as a fuel and oxygen in the air. Such fuel cells are applied to a fuel cell vehicle and the like. The fuel cell vehicle is operated by driving an electric motor using electric energy generated by fuel cells. Here, fuel cells produce water through a chemical reaction between hydrogen and oxygen. There are problems in that the produced water reduces the active surface area of a catalyst surface of a fuel cell, thereby causing a loss in an electrode reaction, and causes a voltage drop by increasing the mass transfer coefficient, thereby reducing the performance of the fuel cell. In this regard, the fuel cell vehicle is provided with a function of frequently draining water produced during the operation of the vehicle. However, even in the case in which produced water is frequently drained, a portion of the water may remain inside a fuel cell instead of being drained. In particular, in the winter, when the fuel cell vehicle is turned off, produced water (i.e., residual water) remaining inside the fuel cell may be frequently frozen. There are problems in that it is difficult to properly supply oxygen and hydrogen due to the freezing of residual water inside the fuel cell and the performance of the fuel cell may be reduced as a normal chemical reaction cannot be performed. Thus, in the winter, when the fuel cell vehicle turned off, residual water is drained and removed from inside the fuel cell by supplying a large amount of air to the load-free fuel cell for a predetermined time. Meanwhile, when a fuel cell vehicle is short of hydrogen serving as a fuel, the fuel cell vehicle is charged with hydrogen at a hydrogen charging station. At the hydrogen charging station, the fuel cell vehicle short of hydrogen cannot be directly charged with hydrogen, and the fuel cell needs to be completely turned off to charge the vehicle with hydrogen. However, when the fuel cell is completely turned off in a low-temperature environment, residual water inside the fuel cell may be frozen, which is problematic. Thus, in the low-temperature environment, a process of draining residual water from inside the fuel cell is performed before the fuel cell is turned off. As the draining of the residual water from inside the fuel cell is completed and the fuel cell is turned off, the fuel cell vehicle can be charged with hydrogen. In the low-temperature environment, a time delay before the charging of hydrogen after the stopping of the vehicle is caused. Thus, affective quality of a user of the hydrogen charging station may be lowered, which is problematic. In addition, since the charging position of the fuel cell vehicle in the hydrogen charging station is fixed, the ground corresponding to the charging position may be frozen by repeatedly discharged residual water, which is problematic. Due to the freezing of the ground, when a fuel cell vehicle enters or exits the hydrogen charging station, a safety problem may occur. The foregoing is intended merely to aid in the understanding of the background of the present disclosure, and is not intended to mean that the present disclosure falls within the purview of the related art that is already known to those skilled in the art. SUMMARY The present disclosure relates generally to a residual water drain system and method of a fuel cell vehicle. Particular embodiments relate to a residual water drain system and method of a fuel cell vehicle configured to, when charging a vehicle with hydrogen is determined to be necessary, drain residual water of a fuel cell through a drain device, turn off the fuel cell, and convert the vehicle into an electric vehicle (EV) mode, thereby preventing a time delay in the charging of hydrogen. Accordingly, embodiments of the present disclosure keep in mind problems occurring in the related art, and embodiments of the present disclosure provide a residual water drain system of a fuel cell vehicle and method configured to, when charging a vehicle with hydrogen is determined to be necessary, drain residual water of a fuel cell through a drain device, turn off the fuel cell, and convert the vehicle into an EV mode, thereby preventing a time delay in the charging of hydrogen. According to one embodiment of the present disclosure, there is provided a residual water drain system of a fuel cell vehicle, the system including a fuel cell, a drain device configured to drain residual water from the fuel cell, and a controller configured to drain residual water from the fuel cell through the drain device, to turn off the fuel cell, and to conver