KR100946529B1 - Method for modeled catalyst temperature at trailing throttle - Google Patents

Abstract

The present invention discloses a catalyst temperature modeling method for decelerating a vehicle. The catalyst temperature modeling method for decelerating a vehicle according to the present invention includes: (a) initializing a counter by sensing a deceleration mode of the vehicle, (b) receiving an engine speed, an intake air amount, and a combustion air fuel ratio; Modeling the exhaust gas temperature for a specific counting time point (N) after initialization, and modeling the catalyst temperature through sub-logics that parameterize the accumulated intake air amount and combustion air fuel ratio after the counter initialization based on the intake air amount, and ( And d) repeatedly modeling the exhaust gas temperature and the catalyst temperature for the counting time point N + 1 after the specific counting time point N according to the sensing result of whether the deceleration mode is continued. Accordingly, the present invention provides a catalyst temperature even when the catalyst temperature of the catalytic converter for purifying the exhaust gas of the engine can rise sharply even when the exhaust gas temperature decreases in a transient state in which the engine speed and the intake air amount change rapidly during vehicle deceleration. By accurately modeling, it is possible to accurately model the phenomenon in which the catalyst temperature rises, falls and maintains regardless of the exhaust gas temperature.

Catalyst temperature, vehicle, deceleration mode

Description

Modeling of catalyst temperature during vehicle deceleration {METHOD FOR MODELED CATALYST TEMPERATURE AT TRAILING THROTTLE}

The present invention relates to a catalyst temperature modeling method for decelerating a vehicle. More particularly, the present invention relates to a catalytic converter for purifying exhaust gas of an engine even when the exhaust gas temperature drops in a transient state in which the engine speed and the intake air amount change rapidly during vehicle deceleration. The present invention relates to a catalyst temperature modeling method when decelerating a vehicle in order to accurately model the catalyst temperature when the catalyst temperature of the catalyst can rise rapidly.

Typically, the catalyst temperature is used as a reference in the Catalytic Converter Temperature Overheating Protection (COP) logic that prevents the catalyst from being damaged by high temperatures, and must be accurately modeled to prevent damage to the catalyst as well as fuel consumption. Can improve.

In other words, if the modeled temperature is lower than the actual catalyst temperature, the catalyst may be damaged.If the modeled temperature is higher than the actual catalyst temperature, the air-fuel ratio is controlled by the COP logic to reduce the catalyst temperature even in unnecessary situations. There is a problem that is worse.

The prior art for modeling such a catalyst temperature is to calculate the temperature deviation that occurs when a given engine speed and intake air amount is given on the basis of the data measured at the exhaust gas temperature and the catalyst temperature at steady state. The temperature deviation at this time means the amount of temperature rise by the heat of chemical reaction in the catalytic converter, whereby the modeling value of the exhaust gas temperature and the modeling value of the catalyst temperature are always the same.

Of course, the changing speed for the modeling value of each temperature can be set differently, but the changing direction cannot be set differently. Therefore, even if the exhaust gas temperature decreases in a transient state in which the engine speed and the intake air volume change drastically, the catalyst temperature is changed. In the case of rapidly rising physical phenomena, there is a serious problem in that the catalyst temperature cannot be accurately modeled.

Accordingly, the present invention has been made to solve the above problems, and an object of the present invention is to purify the exhaust gas of the engine even if the exhaust gas temperature drops in a transient state in which the engine speed and the intake air amount change rapidly during vehicle deceleration. The present invention provides a catalyst temperature modeling method for decelerating a vehicle in order to accurately model the catalyst temperature when the catalyst temperature of the catalytic converter can be rapidly increased.

According to an aspect of the present invention, a catalyst temperature modeling method for decelerating a vehicle includes: (a) initializing a counter by sensing a deceleration mode of a vehicle; (b) engine speed, intake air amount, and combustion; A step of receiving an air-fuel ratio, (c) Models the exhaust gas temperature for a specific counting time point (N) after initialization, and the sub-logic using the intake air amount accumulation value and the combustion air fuel ratio after the counter initialization based on the intake air amount as parameters. Modeling the catalyst temperature through the (d) and the exhaust gas temperature and the catalyst temperature for the counting time point (N + 1) after the specific counting time point (N) in accordance with the sensing result of whether the deceleration mode is continued Iteratively characterized in that it comprises the step of modeling.

Preferably, the catalyst temperature modeling method for decelerating the vehicle may further include (e) driving the engine controller based on the modeled exhaust gas temperature and the catalyst temperature.

Preferably, the exhaust gas temperature is a temperature before the exhaust gas discharged from the engine is sucked into the catalytic converter, or characterized in that the temperature discharged from the catalytic converter.

Preferably, the step (c) is performed through an exhaust gas temperature deviation table at a steady state based on the engine speed and the intake air amount.

TEG_DYNAMIC_N = TEG_DYNAMIC_N-1 + constant * (TEG_STATIC_N-TEG_DYNAMIC_N-1)

(However, TEG_DYNAMIC_N is the exhaust gas temperature model value at time point N, TEG_STATIC_N is the exhaust gas temperature test value at steady state at time point N, and constant is the specific gravity constant value.)

The logic of the exhaust gas temperature is characterized by modeling.

Preferably, the step (c) is performed through a catalyst temperature deviation table at a steady state based on the intake air amount and the combustion air fuel ratio.

CATAL_DYNAMIC_N = CATAL_DYNAMIC_N-1 + [2-D ARRAY] * (CATAL_STATIC_N-CATAL_DYNAMIC_N-1)

(However, CATAL_DYNAMIC_N is the catalyst temperature model value at time point N, CATAL_STATIC_N is the catalyst temperature test value for steady state at time point N, and 2-D ARRAY is a sub-logic whose cumulative air volume value and combustion performance ratio after counter initialization are parameters.)

It is characterized by modeling the catalyst temperature by executing the logic of.

Therefore, in the present invention, even when the exhaust gas temperature decreases in a transient state in which the engine speed and the intake air amount change rapidly during vehicle deceleration, the catalyst temperature of the catalytic converter which purifies the exhaust gas of the engine can rise rapidly. By modeling, there is an advantage that can accurately model all the phenomenon that the catalyst temperature rises, falls, and maintains regardless of the exhaust gas temperature.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the system for modeling the catalyst temperature during vehicle deceleration according to the present invention in detail.

1 is a block diagram of a system for modeling a catalyst temperature during vehicle deceleration according to an embodiment of the present invention. As shown by way of example only in FIG. 1, the system 100 for modeling the catalyst temperature at the time of deceleration of a vehicle detects the deceleration mode of the vehicle and initializes a counter according to a signal transmitted and counts for executing subsequent counting. The unit 110, the parameter measuring unit 120 for measuring parameters including the engine speed, the intake air amount and the combustion air fuel ratio, the exhaust gas temperature for the specific counting time point N after the counter initialization as well as the suction The modeling setting unit 130 for modeling the catalyst temperature through the sub-logic using the cumulative air amount after the counter initialization and the combustion air fuel ratio as parameters based on the air amount, and the exhaust gas temperature and the catalyst temperature formed through the modeling setting. It includes a logic execution unit 140 for driving the engine control device.

FIG. 2 is a flowchart illustrating an operation process of the system 100 for modeling catalyst temperature at vehicle deceleration shown in FIG. 1. As shown by way of example only in FIG. 2, the catalytic temperature modeling method in decelerating the vehicle proceeds by initializing the counter by sensing that the vehicle enters the deceleration mode (S100 and S102).

After that, the parameters of the engine speed, intake air amount and combustion air fuel ratio are measured and received (S104). This is because, when the vehicle decelerates, the engine control device cuts off the fuel or even the small amount of fuel is injected since the intake air amount is the minimum value. Therefore, the generation of thermal energy is lowered, the exhaust gas temperature is lowered and the temperature of the catalytic converter is also a common phenomenon. However, since the reaction rate of the redox catalyst varies depending on the air-fuel ratio of the engine, the heat of catalytic reaction according to the situation also varies.

That is, a special phenomenon may appear rather than a general phenomenon, and in order to model the catalyst temperature in response to such a special phenomenon, the combustion air fuel ratio is set as the measurement parameter with one factor that can move the catalyst model temperature up, down, and maintain. Since the degree of chemical reaction varies depending on the space velocity (exhaust gas amount / catalyst volume) of the catalyst, the amount of intake air that can be measured by the intake air amount sensor or the manifold pressure sensor is calculated by approximating the exhaust gas amount to the intake air amount for introducing the factor. Set it to an additional parameter.

Based on the parameters measured in step S104, the exhaust gas temperature is modeled for a specific counting time point N after initialization, and sub-logics using the cumulative air amount and combustion air fuel ratio after the counter initialization based on the intake air amount as parameters Through modeling the catalyst temperature separately (S106).

The modeling of the exhaust gas temperature is based on an exhaust gas temperature deviation table at steady state based on engine speed and intake air volume.

TEG_DYNAMIC_N = TEG_DYNAMIC_N-1 + constant * (TEG_STATIC_N-TEG_DYNAMIC_N-1)

(However, TEG_DYNAMIC_N is the exhaust gas temperature model value at time point N, TEG_STATIC_N is the exhaust gas temperature test value at steady state at time point N, and constant is the specific gravity constant value.)

By executing logic like this, the exhaust gas temperature is formed.

In addition, the modeling of the catalyst temperature is based on the catalyst temperature deviation table at steady state based on the intake air amount and combustion air fuel ratio.

CATAL_DYNAMIC_N = CATAL_DYNAMIC_N-1 + [2-D ARRAY] * (CATAL_STATIC_N-CATAL_DYNAMIC_N-1)

(However, CATAL_DYNAMIC_N is the catalyst temperature model value at time point N, CATAL_STATIC_N is the catalyst temperature test value for steady state at time point N, and 2-D ARRAY is a sub-logic whose cumulative air volume value and combustion performance ratio after counter initialization are parameters.)

By executing the same logic to form the corresponding catalyst temperature (S108).

For example, the 2-D ARRAY will be described in detail with the following parameter table as an example.

Cumulative Air Volume [g] Combustion Performance Fuel [air mass / fuel mass] 11 12 13 14 20 0 0.8 0.6 0.4 0.1 -0.1 10 0.6 0.4 0.2 0 -0.2 30 0.4 0.2 0 -0.1 -0.3 50 0 -0.1 -0.1 -0.2 -0.3 100 -0.3 -0.3 -0.3 -0.3 -0.3

2-D ARRAY is a positive value as the catalyst temperature is increased further due to exothermal effect (chemical reaction in catalyst) when the combustion air fuel ratio is just before or at the deceleration mode. From the time when it is judged to have sufficiently decelerated at the beginning (for example, when the cumulative intake air amount is 50g), the negative value is converted into a negative value.

Thus, the modeling value for the catalyst temperature rises and falls corresponding to the logic value for the 2-D ARRAY.

In addition, when entering the deceleration mode when the combustion fuel ratio is lean, the chemical reaction rate is insignificant, so that the catalyst temperature does not increase further, so that the logic value for the 2-D ARRAY is set to a negative value regardless of the cumulative intake air amount. It is preferable.

Thereafter, according to a sensing result of whether the additional vehicle deceleration mode is continued, additional counting after a specific counting time point N is performed (S110 and S112), and the exhaust gas for the additional counting time point N + 1. The process of repeatedly modeling the temperature and the catalyst temperature is performed (S114).

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below. I can understand that you can.

In addition, the present invention provides a catalyst temperature even when the catalyst temperature of the catalytic converter for purifying the exhaust gas of the engine can rise sharply even when the exhaust gas temperature decreases in a transient state in which the engine speed and the intake air amount change rapidly during vehicle deceleration. According to the precise modeling, it is an invention that is industrially applicable because the possibility of commercialization or sales is not only sufficient but also practically obvious.

1 is a block diagram of a system for modeling the catalyst temperature during vehicle deceleration according to an embodiment of the present invention, and

FIG. 2 is a flowchart illustrating an operation process of a system for modeling catalyst temperature at vehicle deceleration shown in FIG. 1.

<Description of Symbols for Main Parts of Drawings>

100: modeling system 110: counting unit

120: parameter measuring unit 130: modeling setting unit

140: logic execution unit

Claims (5)

(A) initializing a counter by sensing a deceleration mode of the vehicle; (B) receiving engine speed, intake air amount and combustion air fuel ratio; (C) Model the exhaust gas temperature for a specific counting time point N after initialization, and model the catalyst temperature through sub-logics using the cumulative values of the intake air amount after the counter initialization based on the intake air amount and the combustion air fuel ratio as parameters. Making; And (D) repeatedly modeling the exhaust gas temperature and the catalyst temperature for the counting time point N + 1 after the specific counting time point N in accordance with a sensing result of whether the deceleration mode is continued. A catalyst temperature modeling method for decelerating a vehicle. The method of claim 1, wherein the catalyst temperature modeling method for decelerating the vehicle (E) driving the engine control apparatus based on the modeled exhaust gas temperature and the catalyst temperature. The method of claim 1, wherein the exhaust gas temperature is A catalyst temperature modeling method for decelerating a vehicle, wherein the exhaust gas discharged from the engine is a temperature before being sucked into the catalytic converter or is discharged from the catalytic converter. The method of claim 1 or 2, wherein the step (c) Through the exhaust gas temperature deviation table at a steady state based on the engine speed and the intake air amount TEG_DYNAMIC_N = TEG_DYNAMIC_N-1 + constant * (TEG_STATIC_N-TEG_DYNAMIC_N-1) (However, TEG_DYNAMIC_N is the exhaust gas temperature model value at time point N, TEG_STATIC_N is the exhaust gas temperature test value at steady state at time point N, and constant is the specific gravity constant value.) The catalyst temperature modeling method for decelerating a vehicle, characterized by modeling the exhaust gas temperature by executing logic. The method of claim 1 or 2, wherein the step (c) Through the catalyst temperature deviation table at steady state based on the intake air amount and the combustion air fuel ratio CATAL_DYNAMIC_N = CATAL_DYNAMIC_N-1 + [2-D ARRAY] * (CATAL_STATIC_N-CATAL_DYNAMIC_N-1) (However, CATAL_DYNAMIC_N is the catalyst temperature model value at time point N, CATAL_STATIC_N is the catalyst temperature test value for steady state at time point N, and 2-D ARRAY is a sub-logic whose cumulative air volume value and combustion performance ratio after counter initialization are parameters.) The catalyst temperature modeling method for decelerating a vehicle, characterized by modeling the catalyst temperature by executing logic.

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