阅读说明：本技术 用于判断车辆催化转化器中的错误的系统和方法 (System and method for determining errors in a vehicle catalytic converter ) 是由 李圣夏 于 2019-08-14 设计创作，主要内容包括：本发明公开一种用于判断车辆催化转化器中的错误的系统和方法,防止误判断并提高判断的可靠性。该方法通过考虑燃料喷射状态和燃料喷射切断状态两者来判断催化转化器中是否发生错误。(The invention discloses a system and a method for determining an error in a catalytic converter of a vehicle, preventing misdetermination and improving reliability of determination. The method determines whether an error occurs in the catalytic converter by considering both the fuel injection state and the fuel injection cut state.)

1. A system for determining errors in a catalytic converter of a vehicle, comprising:

a first oxygen sensor that is provided before an inlet of the catalytic converter and detects information on a concentration of oxygen in the exhaust gas;

a second oxygen sensor that is disposed after an outlet of the catalytic converter and detects information on a concentration of oxygen in the exhaust gas; and

a controller that receives information on a concentration of oxygen in the exhaust gas from the first oxygen sensor and the second oxygen sensor to calculate air-fuel ratios and detects a time at which each of the air-fuel ratios reaches a lean reference value or a rich reference value to determine an error in the catalytic converter,

the controller determines that an error has occurred in the catalytic converter when a value smaller than a preset first reference value is obtained from a difference between a time at which the air-fuel ratio calculated based on the information of the first oxygen sensor reaches the rich reference value and a time at which the air-fuel ratio calculated based on the information of the second oxygen sensor reaches the rich reference value in a fuel injection state, and

in the fuel injection cut-off state, the controller suspends the determination of the occurrence of an error in the catalytic converter when a preset second reference value or more is obtained from a difference between a time at which the air-fuel ratio calculated based on the information of the first oxygen sensor reaches the lean reference value and a time at which the air-fuel ratio calculated based on the information of the second oxygen sensor reaches the lean reference value.

2. The system of claim 1, wherein,

the controller finally judges that an error has occurred in the catalytic converter when two conditions are satisfied, the two conditions including:

a first condition in the fuel injection state, in which a value smaller than the preset first reference value is obtained from a difference between a time at which the air-fuel ratio calculated based on the information of the first oxygen sensor reaches the rich reference value and a time at which the air-fuel ratio calculated based on the information of the second oxygen sensor reaches the rich reference value; and

a second condition in the fuel injection cut-off state, in which a value smaller than the preset second reference value is obtained from a difference between a time at which the air-fuel ratio calculated based on the information of the first oxygen sensor reaches the lean reference value and a time at which the air-fuel ratio calculated based on the information of the second oxygen sensor reaches the lean reference value.

3. The system of claim 1, further comprising:

a fuel regulator that regulates a fuel injection amount based on a depression amount of an accelerator pedal,

wherein the controller receives information on the fuel injection state based on the depression amount of the accelerator pedal.

4. The system of claim 1, wherein,

the controller transmits a warning message to a driver in response to determining that an error has occurred in the catalytic converter.

5. A method for determining an error in a vehicle catalytic converter, comprising:

the controller detects an air-fuel ratio measured before an inlet of the catalytic converter and an air-fuel ratio measured after an outlet of the catalytic converter;

the controller detects whether the catalytic converter is in a fuel injection state or a fuel injection cut-off state; and

the controller determines that an error has occurred in the catalytic converter in the fuel injection state when a value smaller than a preset first reference value is obtained from a difference between a time at which an air-fuel ratio measured before an inlet of the catalytic converter reaches a rich reference value and a time at which the air-fuel ratio measured after the outlet of the catalytic converter reaches the rich reference value, and suspends determining an error in the catalytic converter in the fuel injection cut-off state when a preset second reference value or larger is obtained in advance from a difference between a time at which the air-fuel ratio measured before the inlet of the catalytic converter reaches a lean reference value and a time at which the air-fuel ratio measured after the outlet of the catalytic converter reaches the lean reference value.

6. The method of claim 5, further comprising:

the controller finally judges that an error has occurred in the catalytic converter when two conditions are satisfied, the two conditions including:

a first condition in the fuel injection state, in which a value smaller than the preset first reference value is obtained from a difference between a time at which the air-fuel ratio measured before the inlet of the catalytic converter reaches the rich reference value and a time at which the air-fuel ratio measured after the outlet of the catalytic converter reaches the rich reference value; and

a second condition in the fuel injection cut-off state, in which a value smaller than the preset second reference value is obtained from a difference between a time at which the air-fuel ratio measured before the inlet of the catalytic converter reaches the lean reference value and a time at which the air-fuel ratio measured after the outlet of the catalytic converter reaches the lean reference value.

Technical Field

The present disclosure relates to a system and method for determining an error in a catalytic converter of a vehicle, and more particularly, to a system and method for preventing misdetermination when determining whether an error occurs in a catalytic converter.

Background

Modern internal combustion engines, such as gasoline engines, combust a fuel in cylinders and use the thermal energy generated thereby as a source of power. Therefore, the exhaust gas contains harmful components such as nitrogen oxides produced by combustion and carbon monoxide, hydrocarbons, and the like produced by incomplete combustion. To reduce such harmful components in the exhaust gas, the vehicle includes a catalytic converter. The catalytic converter is configured to oxidize harmful components in the exhaust gas by discharging oxygen adsorbed therein to reduce the exhaust gas.

Therefore, in the method for determining whether an error occurs in the catalytic converter, more fuel is injected at the time of fuel injection to make the exhaust gas richer than the stoichiometric air-fuel ratio. Thereafter, it is determined whether an error has occurred in the catalytic converter based on a difference between times at which the oxygen sensors disposed before and after the catalytic converter each display a rich exhaust signal. However, when the driver presses and releases the accelerator pedal within a moment, the fuel injection amount is relatively small, and therefore the temperature of the exhaust gas fails to sufficiently rise. Therefore, the catalytic converter fails to reach the activation temperature. Furthermore, the fuel is unburned and is directly discharged without being oxidized in the catalytic converter. Therefore, the oxygen sensors disposed before and after the catalytic converter display the rich exhaust signal almost simultaneously. In particular, even if the catalytic converter is operating normally, it may be misjudged that an error has occurred in the catalytic converter.

The contents described as the related art are provided only for the background of aiding understanding of the present disclosure, and should not be considered to correspond to the prior art known to those skilled in the art.

Disclosure of Invention

An object of the present disclosure is to provide a system and method for determining an error in a catalytic converter of a vehicle, which prevents misdetermination of an error in the catalytic converter by determining whether an error occurs in the catalytic converter in consideration of both a fuel injection state and a fuel injection cut-off state.

According to an example embodiment of the present disclosure, a system for determining an error in a catalytic converter of a vehicle may include: a first oxygen sensor disposed before an inlet of the catalytic converter and configured to receive (e.g., detect) information about a concentration of oxygen in the exhaust gas; a second oxygen sensor disposed after an outlet of the catalytic converter and configured to receive (e.g., detect) information about a concentration of oxygen in the exhaust gas; and a controller configured to receive information on the concentration of oxygen in the exhaust gas from the first and second oxygen sensors to calculate air-fuel ratios and detect a time at which each air-fuel ratio reaches a lean reference value or a rich reference value to determine an error in the catalytic converter.

In the fuel injection state, the controller may be configured to determine that an error occurs in the catalytic converter when a value smaller than a preset first reference value is obtained from a difference between a time at which the air-fuel ratio calculated based on the information of the first oxygen sensor reaches a rich reference value and a time at which the air-fuel ratio calculated based on the information of the second oxygen sensor reaches the rich reference value. In the fuel injection cut-off state, the controller may be configured to suspend the determination of the occurrence of an error in the catalytic converter when a preset second reference value or more is obtained from a difference between a time at which the air-fuel ratio calculated based on the information of the first oxygen sensor reaches a lean reference value and a time at which the air-fuel ratio calculated based on the information of the second oxygen sensor reaches the lean reference value.

The controller may be configured to eventually determine that an error has occurred in the catalytic converter when two conditions are met, including: a first condition in a fuel injection state in which a value smaller than a preset first reference value is obtained from a difference between a time at which the air-fuel ratio calculated based on the information of the first oxygen sensor reaches a rich reference value and a time at which the air-fuel ratio calculated based on the information of the second oxygen sensor reaches the rich reference value; and a second condition in a fuel injection cut-off state, in which a value smaller than a preset second reference value is obtained from a difference between a time at which the air-fuel ratio calculated based on the information of the first oxygen sensor reaches a lean reference value and a time at which the air-fuel ratio calculated based on the information of the second oxygen sensor reaches the lean reference value.

The system for determining an error in a catalytic converter of a vehicle may further include a fuel regulator configured to regulate a fuel injection amount based on a depression amount of an accelerator pedal. The controller may be configured to receive information on a fuel injection state based on a depression amount of an accelerator pedal. The controller may then be configured to transmit a warning message to the driver in response to determining that an error has occurred in the catalytic converter.

According to another exemplary embodiment of the present disclosure, a method for determining an error in a catalytic converter of a vehicle may include: detecting an air-fuel ratio measured before an inlet of the catalytic converter and an air-fuel ratio measured after an outlet of the catalytic converter; detecting whether the catalytic converter is in a fuel injection state or a fuel injection cut-off state; and determining that an error has occurred in the catalytic converter in the fuel injection state when a value smaller than a preset first reference value is obtained from a difference between a time at which the air-fuel ratio measured before the inlet of the catalytic converter reaches a rich reference value and a time at which the air-fuel ratio measured after the outlet of the catalytic converter reaches the rich reference value, and suspending determination of the error in the catalytic converter in the fuel injection cut-off state when a preset second reference value or more is obtained in advance from a difference between a time at which the air-fuel ratio measured before the inlet of the catalytic converter reaches a lean reference value and a time at which the air-fuel ratio measured after the outlet of the catalytic converter reaches the lean reference value.

The error determination may include a final determination that an error has occurred in the catalytic converter when two conditions are satisfied, the two conditions including: a first condition in a fuel injection state in which a value smaller than a preset first reference value is obtained from a difference between a time at which the air-fuel ratio measured before an inlet of the catalytic converter reaches a rich reference value and a time at which the air-fuel ratio measured after an outlet of the catalytic converter reaches the rich reference value; and a second condition in a fuel injection cut-off state, in which a value smaller than a preset second reference value is obtained from a difference between a time at which the air-fuel ratio measured before the inlet of the catalytic converter reaches a lean reference value and a time at which the air-fuel ratio measured after the outlet of the catalytic converter reaches the lean reference value.

Drawings

The above and other features of the present invention will now be described in detail with reference to certain exemplary embodiments thereof as illustrated in the accompanying drawings, which are given by way of illustration only, and thus are not limiting of the invention, and wherein:

FIG. 1 is a configuration diagram illustrating a system for determining an error in a vehicle catalytic converter according to an exemplary embodiment of the present disclosure;

FIGS. 2 and 3 are graphs illustrating a system for determining an error in a catalytic converter of a vehicle according to the prior art and according to an exemplary embodiment of the present disclosure; and

fig. 4 and 5 are flowcharts illustrating a method for determining an error in a catalytic converter of a vehicle according to an exemplary embodiment of the present disclosure.

Detailed Description

It will be understood that the term "vehicle" or "vehicular" or other similar terms as used herein generally include motor vehicles, such as passenger vehicles including Sport Utility Vehicles (SUVs), buses, trucks, various commercial vehicles, watercraft including various boats and ships, aircraft, and the like, and includes hybrid vehicles, electric vehicles, plug-in hybrid vehicles, hydrogen-powered vehicles, and other alternative fuel (e.g., fuel from resources other than petroleum) vehicles.

While the exemplary embodiments are described as using multiple units to execute the exemplary process, it will be understood that the exemplary process may also be executed by one or more modules. In addition, it will be understood that the term "controller"/"control unit" refers to a hardware device that includes a memory and a processor. The memory is configured to store modules and the processor is specifically configured to execute the modules to perform one or more processes described further below.

Further, the control logic of the present disclosure may be embodied as a non-transitory computer readable medium on a computer readable medium containing executable program instructions executed by a processor, controller/control unit, or the like. Examples of computer readable media include, but are not limited to, ROM, RAM, Compact Disc (CD) -ROM, magnetic tape, floppy disk, flash drive, smart card, and optical data storage. The computer readable medium CAN also be distributed over network coupled computer systems so that the computer readable medium is stored and executed in a distributed fashion, such as by a telematics server or Controller Area Network (CAN).

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Hereinafter, a system and method for determining an error in a catalytic converter of a vehicle according to an exemplary embodiment of the present disclosure will be described with reference to the accompanying drawings.

FIG. 1 is a configuration diagram illustrating a system for determining an error in a vehicle catalytic converter according to an exemplary embodiment of the present disclosure; FIGS. 2 and 3 are graphs illustrating a system for determining an error in a catalytic converter of a vehicle according to the prior art and according to an exemplary embodiment of the present disclosure; and fig. 4 and 5 are flowcharts illustrating a method for determining an error in a catalytic converter of a vehicle according to an exemplary embodiment of the present disclosure.

As shown in fig. 1, a system for determining an error in a catalytic converter of a vehicle according to an exemplary embodiment of the present disclosure may include: a first oxygen sensor 10 disposed before an inlet of the catalytic converter 50 and configured to receive information on a concentration of oxygen in the exhaust gas; a second oxygen sensor 20 disposed after an outlet of the catalytic converter 50 and configured to receive information on a concentration of oxygen in the exhaust gas; and a controller 30 configured to receive information on the concentration of oxygen in the exhaust gas from the first and second oxygen sensors 10 and 20 to calculate air-fuel ratios and detect the time at which each air-fuel ratio reaches a lean reference value or a rich reference value to determine an error in the catalytic converter 50.

In the fuel injection state, the controller 30 may be configured to determine that an error occurs in the catalytic converter 50 when a value smaller than a preset first reference value is obtained from a difference between a time at which the first oxygen sensor 10 reaches the rich reference value and a time at which the second oxygen sensor 20 reaches the rich reference value. In the fuel injection cut-off state, the controller 30 may be configured to suspend the determination of the occurrence of an error in the catalytic converter 50 when a preset second reference value or more is obtained from a difference between the time at which the first oxygen sensor 10 reaches the lean reference value and the time at which the second oxygen sensor 20 reaches the lean reference value.

In particular, the first and second oxygen sensors 10 and 20 may each be disposed before (e.g., in front of) and after the catalytic converter 50, and the first and second oxygen sensors 10 and 20 may each be configured to receive information about the concentration of oxygen in the exhaust gas. The first oxygen sensor 10 and the second oxygen sensor 20 may be oxygen sensors configured to obtain or sense the concentration of oxygen in exhaust gas to determine lean exhaust gas or rich exhaust gas or air-fuel ratio sensors configured to determine the air-fuel ratio (λ value) of exhaust gas.

Meanwhile, the controller 30 may be configured to receive information about the concentration of oxygen in the exhaust gas from the first and second oxygen sensors 10 and 20 to calculate air-fuel ratios and detect the time when each air-fuel ratio reaches a preset lean reference value or a preset rich reference value. In other words, in the fuel injection state, the controller 30 may be configured to determine that an error has occurred in the catalytic converter 50 when a value smaller than a preset first reference value is obtained from a difference between a time at which the air-fuel ratio calculated based on the information on the concentration of oxygen in the exhaust gas measured by the first oxygen sensor 10 reaches a rich reference value and a time at which the air-fuel ratio calculated based on the information on the concentration of oxygen in the exhaust gas measured by the second oxygen sensor 20 reaches the rich reference value. For example, the rich reference value may be preset to an air-fuel ratio of 1, and the lean reference value may be preset to an air-fuel ratio of 0.65, but is not limited thereto.

The fuel injection state may depend on a fuel injection amount input through a fuel regulator 40, the fuel regulator 40 being configured to regulate the fuel injection amount based on the depression amount of an accelerator pedal 41. Therefore, the controller 30 may be configured to receive information on the fuel injection state based on the depression amount of the accelerator pedal 41 to determine whether an error occurs in the catalytic converter 50.

In other words, when the driver depresses the accelerator pedal (e.g., applies a force to the accelerator pedal) to inject fuel, the controller 30 may be configured to determine that the catalytic converter 50 is operating normally when a preset first reference value or more is obtained from a difference between a time at which the air-fuel ratio calculated based on the information of the first oxygen sensor 10 reaches a rich reference value and a time at which the air-fuel ratio calculated based on the information of the second oxygen sensor 20 reaches the rich reference value.

However, the controller 30 may be configured to determine that an error has occurred in the catalytic converter 50 when a value smaller than a preset first reference value is obtained from a difference between the time at which the air-fuel ratio calculated based on the information of the first oxygen sensor 10 reaches the rich reference value and the time at which the air-fuel ratio calculated based on the information of the second oxygen sensor 20 reaches the rich reference value. In particular, when the catalytic converter 50 is operating normally and the oxidation-reduction reaction is being performed normally, the first reference value may be set based on the time measured when the air-fuel ratio calculated based on the information of the first oxygen sensor 10 and the air-fuel ratio calculated based on the information of the second oxygen sensor 20 each become the stoichiometric air-fuel ratio. Therefore, the preset first reference value may depend on the catalytic converter 50 and the engine specification.

When the driver presses and releases the accelerator pedal 41 within a moment (e.g., suddenly), the fuel injection amount is insufficient, and therefore the temperature of the exhaust gas fails to sufficiently rise even if the driver presses the accelerator pedal 41 to inject the fuel. Therefore, when the catalytic converter 50 fails to reach the activation temperature, unburned fuel may be discharged without being oxidized in the catalytic converter 50. Therefore, it is possible to measure or judge that the air-fuel ratio calculated based on the information of the first oxygen sensor 10 and the air-fuel ratio calculated based on the information of the second oxygen sensor 20 are in a rich exhaust gas state. In other words, when the driver suddenly presses and releases the accelerator pedal, the fuel injection amount is insufficient, and therefore, even if the catalytic converter 50 is operating normally, it may be misjudged that an error has occurred in the catalytic converter 50.

Therefore, in the present disclosure, it is possible to more accurately determine whether an error has occurred in the catalytic converter based on the fuel injection cut state and the fuel injection state. In other words, in the present disclosure, when the driver in the normal driving state releases the pressing force from the accelerator pedal 41 and thus cuts off the fuel injection, it may be determined whether the difference between the times at which each air-fuel ratio reaches the lean reference value, which is calculated based on the information input through the first and second oxygen sensors 10 and 20, has a value smaller than a preset second reference value or more. In other words, when the accelerator pedal 41 is suddenly pressed and released, the fuel injection amount required for the catalytic converter 50 to reach the activation temperature cannot be ensured.

Therefore, it is possible to determine whether an error occurs in the catalytic converter 50 based on the lean reference value under a condition relatively smaller than a normal condition for determining whether an error occurs in the catalytic converter 50. In particular, when the catalytic converter 50 is operating normally and the oxidation-reduction reaction is being performed normally, the second reference value may be set based on the time measured when the air-fuel ratio calculated based on the information of the first oxygen sensor 10 and the air-fuel ratio calculated based on the information of the second oxygen sensor 20 each become the stoichiometric air-fuel ratio. Therefore, the preset second reference value may depend on the catalytic converter 50 and the engine specification.

Therefore, when the driver releases the pressing force to depress the accelerator pedal 41 and thus cuts off the fuel injection, the controller 30 may be configured to suspend the determination of the occurrence of an error in the catalytic converter 50 when a preset second reference value or more is obtained from the difference between the time at which the air-fuel ratio calculated based on the information of the first oxygen sensor 10 reaches the lean reference value and the time at which the air-fuel ratio calculated based on the information of the second oxygen sensor 20 reaches the lean reference value. Therefore, the controller 30 can prevent misjudgment of the occurrence of an error in the vehicle catalytic converter 50. By determining an error in the catalytic converter 50 in consideration of the fuel injection cut state, it is possible to more accurately determine whether the catalytic converter 50 is operating normally.

Thus, the controller 30 may be configured to eventually determine that an error has occurred in the catalytic converter 50 when two conditions are satisfied, including: a first condition in a fuel injection state in which a value smaller than a preset first reference value is obtained from a difference between a time at which the air-fuel ratio calculated based on the information of the first oxygen sensor 10 reaches a rich reference value and a time at which the air-fuel ratio calculated based on the information of the second oxygen sensor 20 reaches the rich reference value; and a second condition in a fuel injection cut-off state in which a value smaller than a preset second reference value is obtained from a difference between a time at which the air-fuel ratio calculated based on the information of the first oxygen sensor 10 reaches a lean reference value and a time at which the air-fuel ratio calculated based on the information of the second oxygen sensor 20 reaches the lean reference value.

As described above, in the present disclosure, it is possible to determine whether an error has occurred in the catalytic converter 50 in consideration of the fuel injection state and the fuel injection cut state. Since the fuel injection state may depend on the depression of the accelerator pedal 41, conditions suitable for each of the different states may be applied to more accurately determine whether an error has occurred in the catalytic converter 50. In this way, the possibility of misjudging an error in the catalytic converter 50 can be minimized.

For example, as shown in fig. 2, in the related art, when the driver suddenly presses and releases the accelerator pedal, the fuel injection amount is insufficient, and therefore, even if the catalytic converter 50 operates normally, the catalytic converter 50 fails to reach the activation temperature. Therefore, the catalytic converter 50 has a reduced oxygen adsorption capacity. As shown in part a of fig. 2, a value smaller than the first reference value is obtained from the difference between the time at which the air-fuel ratio calculated based on the information of the first oxygen sensor 10 reaches the rich reference value and the time at which the air-fuel ratio calculated based on the information of the second oxygen sensor 20 reaches the rich reference value within a moment. Therefore, it may be misjudged that an error has occurred in the catalytic converter 50.

FIG. 3 shows a driver suddenly pressing and releasing the accelerator pedal, thus shutting off fuel injection, according to the present disclosure; part B in fig. 3 shows that each air-fuel ratio reaches the rich reference value for a moment. However, as shown in part C in fig. 3, when a preset second reference value or more is obtained in advance from the difference between the time at which the air-fuel ratio calculated based on the information of the first oxygen sensor 10 reaches the lean reference value and the time at which the air-fuel ratio calculated based on the information of the second oxygen sensor 20 reaches the lean reference value, it is not determined that an error has occurred in the catalytic converter 50, and it is possible to suspend determining an error in the catalytic converter.

Therefore, in the fuel injection state and the fuel injection cut state, it is possible to prevent an error from occurring in the misjudgment of the catalytic converter 50, and it is possible to achieve an accurate judgment by: comparing and judging the time when each air-fuel ratio reaches a lean reference value or a rich reference value; suspending judgment of an error in the catalytic converter when any one of the conditions is not satisfied; and finally judges that an error has occurred in the catalytic converter 50 when all the conditions are satisfied. Meanwhile, the controller 30 may be configured to transmit a warning message to the driver in response to detecting the occurrence of the error in the catalytic converter 50 to provide notification about the occurrence of the error in the catalytic converter 50. Therefore, when an error occurs in the catalytic converter 50, a warning lamp in a vehicle display or an instrument panel may be turned on.

As shown in fig. 4 and 5, a method for determining an error in a catalytic converter of a vehicle according to an exemplary embodiment of the present disclosure may include: detecting an air-fuel ratio measured before (e.g., before) the inlet of the catalytic converter 50 and an air-fuel ratio measured after the outlet of the catalytic converter 50 (S10); detecting whether fuel is injected or fuel injection is cut off (S20); and determining that an error has occurred in the catalytic converter 50 in the fuel injection state when a value smaller than a preset first reference value is obtained from a difference between a time at which the air-fuel ratio measured before the inlet of the catalytic converter 50 reaches a rich reference value and a time at which the air-fuel ratio measured after the outlet of the catalytic converter 50 reaches the rich reference value (S30), and suspending determining an error in the catalytic converter 50 in the fuel injection cut-off state when a preset second reference value or more is obtained in advance from a difference between a time at which the air-fuel ratio measured before the inlet of the catalytic converter 50 reaches a lean reference value and a time at which the air-fuel ratio measured after the outlet of the catalytic converter 50 reaches a lean reference value.

In other words, when the driver depresses the accelerator pedal to inject fuel, it may be determined that the catalytic converter 50 is operating normally when a preset first reference value or more is obtained from the difference between the time at which the air-fuel ratio measured before the inlet of the catalytic converter 50 reaches the rich reference value and the time at which the air-fuel ratio measured after the outlet of the catalytic converter 50 reaches the rich reference value. However, when a value smaller than the preset first reference value is obtained from the difference between the time at which the air-fuel ratio reaches the rich reference value measured before the inlet of the catalytic converter 50 and the time at which the air-fuel ratio reaches the rich reference value measured after the outlet of the catalytic converter 50, it may be judged that an error has occurred in the catalytic converter 50.

When the accelerator pedal 41 is suddenly pressed and released, the fuel injection amount required for the catalytic converter 50 to reach the activation temperature cannot be ensured. Therefore, it is possible to determine whether an error occurs in the catalytic converter 50 based on the lean reference value under a condition lower than the normal condition for determining whether an error occurs in the catalytic converter 50.

Therefore, when the driver releases the pressing force to depress the accelerator pedal 41 and thus cuts off the fuel injection, it is possible to prevent erroneous judgment of the occurrence of an error in the catalytic converter by suspending judgment of the occurrence of an error in the catalytic converter when a preset second reference value or more is obtained from the difference between the time at which the air-fuel ratio measured before the inlet of the catalytic converter 50 reaches the lean reference value and the time at which the air-fuel ratio measured after the outlet of the catalytic converter 50 reaches the lean reference value. Therefore, by determining an error in the catalytic converter in consideration of the fuel injection cut state, it is possible to more accurately determine whether the catalytic converter is operating normally.

Meanwhile, the error determination step S30 may include finally determining that an error has occurred in the catalytic converter 50 when two conditions are satisfied, including: a first condition in a fuel injection state in which a value smaller than a preset first reference value is obtained from a difference between a time at which the air-fuel ratio measured before the inlet of the catalytic converter 50 reaches a rich reference value and a time at which the air-fuel ratio measured after the outlet of the catalytic converter 50 reaches the rich reference value; and a second condition in a fuel injection cut-off state in which a value smaller than a preset second reference value is obtained from a difference between a time at which the air-fuel ratio measured before the inlet of the catalytic converter 50 reaches a lean reference value and a time at which the air-fuel ratio measured after the outlet of the catalytic converter 50 reaches the lean reference value.

As described above, in the present disclosure, it is possible to determine whether an error has occurred in the catalytic converter 50 in consideration of the fuel injection state and the fuel injection cut state. Since the fuel injection state may depend on the depression of the accelerator pedal 41, conditions suitable for each of the different states are applied to more accurately determine whether an error has occurred in the catalytic converter 50. Therefore, the possibility of misjudging an error in the catalytic converter 50 can be minimized.

In the system and method for determining an error in a vehicular catalytic converter having the above-described structure, when it is determined whether an error occurs in the catalytic converter by determining whether an error occurs in the catalytic converter in consideration of both the fuel injection state and the fuel injection cut-off state, it is possible to prevent erroneous determination and to improve the reliability of the determination.

While the disclosure has been shown and described with respect to certain exemplary embodiments, it will be apparent to those skilled in the art that various modifications and changes may be made to the disclosure without departing from the spirit and scope of the disclosure as defined in the claims.