KR102201276B1 - Control method for vehicle - Google Patents

Abstract

The present invention includes a super control amount calculation step of obtaining a target number of revolutions to control a supercharger from a supercharger control map according to a driving mode and driving condition of a vehicle; A turbo control amount calculation step of obtaining a target vane angle for controlling the turbocharger from the turbocharger control map according to the driving mode and driving condition of the vehicle; An open mass calculation step of calculating the amount of reformed gas from the reformed gas composition prediction model according to the reformer conversion efficiency according to the temperature of the reformer and the fuel injection amount of the reformer; A turbo control amount correction step of receiving a target rotation speed of the supercharger and correcting a target vane angle of the turbocharger; And a super control amount correction step of correcting the target rotation speed of the supercharger by receiving the corrected target vane angle and the amount of reformed gas of the reformer.

Description

Vehicle control method{CONTROL METHOD FOR VEHICLE}

The present invention relates to a vehicle control method, and more particularly, to a vehicle control method including a turbocharger, a supercharger, and a reformer.

The turbocharger of the vehicle drives the turbine with the energy of the exhaust gas of the engine, and the compressor pressurizes the intake air with the rotational force of the turbine and supplies it to the combustion chamber, and the VGT (Variable Geometry Turbocharger) adjusts the angle of the vane. By controlling the flow of exhaust gas flowing into the turbine, it is possible to adjust the boost pressure by the compressor.

A supercharger refers to a component provided to actively control a compressor by an electric motor to pressurize intake air and supply it to the combustion chamber.

The reformer of a vehicle is installed in the exhaust gas recirculation (EGR) line, and is installed so that the injected fuel is reformed with hydrogen and supplied to the combustion chamber together with the EGR gas.

The matters described as the background technology of the present invention are only for enhancing an understanding of the background of the present invention, and should not be taken as acknowledging that they correspond to the prior art already known to those of ordinary skill in the art. Will be

KR1020150113192 A

The present invention maximizes the utilization of the turbocharger, supercharger, and reformer in a vehicle equipped with a turbocharger, supercharger, and reformer, thereby contributing to the reduction of nitrogen oxide emissions in exhaust gas by improving EGR performance, and speeding up the intake charge. It is an object of the present invention to provide a vehicle control method capable of improving engine output performance by providing sufficient and accurate provision, and further reducing fuel required for regeneration of LNT (Lean Nox Trap) catalysts.

The control method of the vehicle of the present invention for achieving the above object,

A super control amount calculation step of obtaining a target number of revolutions for controlling the supercharger from the supercharger control map according to the driving mode and driving condition of the vehicle;

A turbo control amount calculation step of obtaining a target vane angle for controlling the turbocharger from the turbocharger control map according to the driving mode and driving condition of the vehicle;

An open mass calculation step of calculating the amount of reformed gas from the reformed gas composition prediction model according to the reformer conversion efficiency according to the temperature of the reformer and the fuel injection amount of the reformer;

A turbo control amount correction step of receiving a target rotation speed of the supercharger and correcting a target vane angle of the turbocharger;

A super control amount correction step of receiving the corrected target vane angle and the amount of reformed gas of the reformer and correcting the target rotation speed of the supercharger;

It characterized in that it is configured to include.

The present invention includes a step of calculating the amount of NOx occluded in the LNT catalyst from the NOx occlusion model of the LNT catalyst by receiving a signal from the NOx sensor;

A first valve opening calculation step of calculating a valve opening of a control valve capable of supplying the amount of reformed gas required for regeneration of the LNT catalyst from the reformer to the LNT catalyst from the LNT regeneration map according to the amount of NOx calculated from the NOx storage model; and ;

A valve opening correction step of receiving the amount of reformed gas and correcting the valve opening;

A valve operation step of operating the control valve according to the corrected valve opening degree;

It may be configured to further include.

In the super control amount correction step

The target rotation speed of the supercharger may be corrected by considering the valve opening corrected in the valve opening correction step together with the corrected target vane angle and the amount of reformed gas.

In the super control amount correction step

The target rotation speed of the supercharger may be corrected by considering the amount of EGR recycled to the engine together with the corrected target vane angle and the amount of reformed gas.

In the super control amount correction step

The target rotation speed of the supercharger may be corrected by considering the valve opening corrected in the valve opening correction step and the amount of EGR recirculated to the engine together with the corrected target vane angle and the amount of reformed gas.

The present invention includes a collection amount calculation step of receiving a signal from a differential pressure sensor and calculating an amount of PM collected in the DPF from a collection amount model of the DPF;

A second valve opening degree calculating step of calculating a valve opening degree of a control valve capable of supplying an amount of reformed gas required for the DPF regeneration from the reformer to the DPF from the DPF regeneration map according to the PM amount calculated from the collection amount model;

A valve opening correction step of receiving the amount of reformed gas and correcting the valve opening;

A valve operation step of operating the control valve according to the corrected valve opening degree;

It may be configured to further include.

The driving mode may include a transient driving mode, a normal driving mode, an eco driving mode, a normal driving mode, a sports mode, a DPF regeneration mode, and a desulfurization mode;

The driving situation may include an engine speed, an accelerator pedal operation amount, a change rate of an accelerator pedal operation amount, an engine intake air amount, an intake air temperature, a coolant temperature, and a vehicle speed.

The present invention maximizes the utilization of the turbocharger, supercharger, and reformer in a vehicle equipped with a turbocharger, supercharger, and reformer, thereby contributing to the reduction of nitrogen oxide emissions in exhaust gas by improving EGR performance, and speeding up the intake charge. Also, it improves engine output performance by providing sufficient and accurate supply, and further reduces fuel required for regeneration of LNT (Lean Nox Trap) catalyst or DPF (Diesel Particulate Filter).

1 is a diagram illustrating an engine of a vehicle to which the present invention can be applied and an intake and exhaust system of the engine;
2 is a block diagram illustrating a first embodiment of a method for controlling a vehicle according to the present invention;
3 is a block diagram illustrating a second embodiment of a vehicle control method according to the present invention.

Referring to FIG. 1, a main configuration of an engine of a vehicle to which the present invention can be applied and an intake/exhaust device thereof is shown. In other words, the exhaust gas of the engine E passes through LNT or DPF or both (hereinafter collectively referred to as'post-treatment device') after rotating the turbine of the turbocharger (T/C) and into the atmosphere. The compressor is discharged and rotated by the rotational force of the turbine is configured to pressurize the intake air and supply it to the engine E via the intercooler IC.

Here, an EGR line 1 connecting the exhaust gas passing through the post-treatment device to the engine intake side is configured, and a reformer RF and a supercharger S/C are installed in the EGR line 1, The EGR gas blown from the supercharger S/C is configured to be supplied to the engine E or supplied to the front end of the aftertreatment device by the control valve 3.

The present invention is a technology applied to a vehicle equipped with a turbocharger (T/C), a supercharger (S/C) and a reformer (RF) as described above, and the embodiments of the present invention are applied to the driving mode and driving situation of the vehicle. A super control amount calculation step (S10) of obtaining a target number of revolutions for controlling the supercharger (S/C) from the supercharger control map accordingly; A turbo control amount calculation step (S20) of obtaining a target vane angle to control the turbocharger (T/C) from the turbocharger control map according to the driving mode and driving condition of the vehicle; An open mass calculation step (S30) of calculating an amount of reformed gas from a reformed gas composition prediction model according to a reformer (RF) conversion efficiency according to a temperature of the reformer (RF) and a fuel injection amount of the reformer (RF); A turbo control amount correction step (S40) of receiving a target rotation speed of the supercharger (S/C) and correcting a target vane angle of the turbocharger (T/C); And a super control amount correction step S50 of receiving the corrected target vane angle and the amount of reformed gas of the reformer RF and correcting the target rotation speed of the supercharger S/C.

Here, the driving mode of the vehicle includes a transient driving mode, a steady state driving mode, an eco driving mode, a normal driving mode, a sports mode, a DPF regeneration mode, a desulfurization mode, and the like, and the driving situation is the engine speed, the accelerator pedal. The operation amount, the rate of change of the accelerator pedal operation amount, engine intake air amount, intake air temperature, coolant temperature, vehicle speed, etc., and the super control amount calculation step (S10) and the turbo control amount calculation step (S20) are the driving of the vehicle as described above. The current supercharger (S/C) and turbocharger (T/C) are basically calculated from the predetermined supercharger control map and turbocharger control map according to the mode and driving conditions.

Accordingly, the supercharger control map and the turbocharger control map may be previously stored in an ECU (Electronic Control Unit) or the like through a number of experiments and analysis according to the driving modes and driving conditions of various vehicles as described above.

The reformed gas composition prediction model is configured in advance to calculate the amount of reformed gas by inputting the reformer conversion efficiency data and the reformer fuel injection amount according to the temperature of the reformer RF.

The turbo control amount correction step (S40) is to allow the turbocharger correction unit to correct the target vane angle output through the turbocharger control map by reflecting the target rotation speed of the supercharger (S/C). The target vane angle belongs to the vane angle area where the efficiency of the turbocharger (T/C) is relatively low, and the target rotation speed of the supercharger (S/C) is significantly lower than the allowable limit rotation speed of the supercharger (S/C). In this case, the turbocharger correction unit corrects the target vane angle to a region in which the efficiency of the turbocharger T/C is relatively high within a predetermined range.

In this case, in the super control amount correction step (S50), the target rotation speed calculated in the super control amount calculation step (S10) is corrected in consideration of the target vane angle corrected by the turbo control amount correction step (S40). The rotation speed of the supercharger is controlled higher than the target rotation speed to compensate for the insufficient supercharge amount in the turbocharger.

Through such control, it is possible to improve the output of the engine by providing the engine intake supercharged quickly, sufficiently and accurately.

In the super control amount correction step (S50), in addition to the corrected target vane angle by the turbo control amount correction step (S40), the amount of reformed gas of the reformer (RF) is input, and the target rotation speed of the supercharger (S/C) is determined accordingly. Correct.

For example, when the amount of reformed gas by the reformer (RF) is relatively high, the EGR replacement performance of the reformed gas can be expected to be relatively high. Since it is possible, the correction to lower the target rotation speed through the super control amount calculation step (S10) is performed. Of course, when the amount of reformed gas is relatively low, it will be possible to perform a correction to increase the target rotation speed.

For reference, here, the'EGR performance' means the ability to reduce nitrogen oxides in the exhaust gas by inflow of the recycled exhaust gas or the reformed gas into the combustion chamber, and the'EGR replacement performance' means the reformed gas is recycled. It refers to the performance that flows into the combustion chamber instead of exhaust gas and ultimately contributes to the reduction of nitrogen oxides in exhaust gas.

In addition, in the embodiment of FIG. 2, the storage amount calculation step (S60) of receiving a signal from the NOx sensor and calculating the amount of NOx stored in the LNT catalyst from the NOx storage model of the LNT catalyst; A first calculating the valve opening degree of the control valve 3 capable of supplying the amount of reformed gas required for regeneration of the LNT catalyst from the reformer (RF) to the LNT catalyst according to the amount of NOx calculated from the NOx storage model. 1 valve opening calculation step (S70) and; A valve opening correction step (S80) of receiving the reformed gas amount and correcting the valve opening; A valve operation step (S90) of operating the control valve 3 according to the corrected valve opening degree (S90).

That is, the NOx storage model of the LNT catalyst is pre-configured to calculate the amount of NOx stored in the LNT catalyst according to the signal of the NOx sensor, and by continuously inputting the signal of the NOx sensor to this NOx storage model. When the amount of NOx currently occluded in the LNT catalyst can be estimated arithmetically, and the estimated amount of NOx stored in the LNT regeneration map is inputted, the LNT regeneration map is at a certain point for regeneration of the LNT catalyst. 3) is opened to output how much to supply to the front end of the LNT catalyst, and if the control valve 3 is controlled according to this output value, the reforming gas is supplied to the front end of the LNT catalyst so that the LNT catalyst can be regenerated.

At this time, in the valve opening correction step (S80), the valve opening is corrected according to the amount of the reformed gas calculated from the open mass calculation step (S30).For example, when the amount of reformed gas is relatively large, the valve opening is When the amount of reformed gas is relatively small and the amount of reformed gas is relatively small, correction is performed to increase the valve opening, so that the reformed gas of an appropriate level without excess or shortage in the regeneration of the LNT catalyst can be supplied.

In this way, by not injecting a separate fuel for the regeneration of the LNT catalyst, the fuel injected into the reformer (RF) can be used to regenerate the LNT catalyst using the reformed gas, so that fuel is separately used for the regeneration of the LNT catalyst. It is possible to obtain an effect of reducing fuel required for regeneration by supplying the correct reformed gas by the control valve 3 and the supercharger (S/C) without consumption.

Meanwhile, in the super control amount correction step (S50), the target rotation speed of the supercharger (S/C) is considered by considering the corrected valve opening degree in the valve opening degree correction step (S80) together with the corrected target vane angle and the amount of reformed gas. Can be corrected.

That is, in controlling the supercharger (S/C), in addition to the corrected target vane angle and the amount of reformed gas, the control valve required for regeneration of the LNT catalyst ( When the valve opening of 3) is formed, the target rotation speed of the supercharger (S/C), which was previously set mainly for performing the EGR function, does not affect the performance of the previous EGR function, and the reformed gas supply for the regeneration of the LNT catalyst. The correction is made to raise it to the level possible.

In addition, in the super control amount correction step (S50), the target rotation speed of the supercharger S/C may be corrected by considering the amount of EGR recycled to the engine together with the corrected target vane angle and the amount of reformed gas.

That is, by inversely estimating the amount of EGR supplied to the engine by the operation of the supercharger (S/C) from the signal of a wide range oxygen sensor installed in the engine exhaust system, the target EGR amount is calculated. This is to enable feedback control of the rotation speed of the supercharger so that it can be followed. Through this, more accurate EGR control becomes possible, thereby reducing the emission of nitrogen oxides, thereby making it possible to respond to various environmental regulations.

For reference, according to FIG. 2, in the super control amount correction step (S50), the valve opening corrected in the valve opening degree correction step (S80) and the amount of EGR recirculated to the engine together with the corrected target vane angle and reformed gas amount. It is expressed as correcting the target rotation speed of the supercharger in consideration.

FIG. 3 shows another embodiment of the present invention, which is substantially expressed as regenerating the LNT catalyst in the above-mentioned embodiment, but in the embodiment of FIG. 3, the DPF is regenerated, not the LNT catalyst. It is expressed as

That is, the embodiment of FIG. 3 includes a collection amount calculation step (S110) of receiving a signal from a differential pressure sensor and calculating the amount of PM collected in the DPF from the collection amount model of the DPF, in addition to parts common to the embodiment of FIG. 2; A second valve that calculates the valve opening degree of the control valve 3 that can supply the amount of reformed gas required for the DPF regeneration from the reformer RF to the DPF, from the DPF regeneration map according to the amount of PM calculated from the collection amount model. Opening degree calculation step (S120); A valve opening correction step (S80) of receiving the reformed gas amount and correcting the valve opening; It is configured to further include a valve operation step (S90) of operating the control valve (3) according to the corrected valve opening.

Here, there is only a difference in regenerating DPF instead of the LNT catalyst, and the rest of the matters are substantially the same as those of the embodiment of FIG. 2, so a detailed description will be omitted.

Although the present invention has been illustrated and described with reference to specific embodiments, it is understood in the art that the present invention can be variously improved and changed within the scope of the technical spirit of the present invention provided by the following claims. It will be obvious to a person of ordinary knowledge.

One; EGR line
3; Control valve
E; engine
T/C; Turbocharger
IC; Intercooler
RF; Reformer
S/C; Supercharger
S10; Super control amount calculation step
S20; Turbo control amount calculation step
S30; Dog mass calculation step
S40; Turbo control amount correction step
S50; Super control amount correction step
S60; Storage amount calculation step
S70; Step of calculating the first valve opening
S80; Valve opening correction step
S90; Valve operation stage
S110; Steps of calculating collection amount
S120; Step of calculating the second valve opening

Claims (10)

A super control amount calculating step of obtaining a target number of revolutions for controlling the supercharger from the supercharger control map according to the driving mode and driving condition of the vehicle;
A turbo control amount calculation step of obtaining a target vane angle for controlling the turbocharger from the turbocharger control map according to the driving mode and driving condition of the vehicle;
An open mass calculation step of calculating the amount of reformed gas from the reformed gas composition prediction model according to the reformer conversion efficiency according to the temperature of the reformer and the fuel injection amount of the reformer;
A turbo control amount correction step of receiving a target rotation speed of the supercharger and correcting a target vane angle of the turbocharger;
A super control amount correction step of receiving the corrected target vane angle and the amount of reformed gas of the reformer and correcting the target rotation speed of the supercharger;
Vehicle control method, characterized in that configured to include. The method according to claim 1,
An occlusion amount calculating step of receiving a signal from the NOx sensor and calculating an amount of NOx occluded in the LNT catalyst from the NOx occlusion model of the LNT catalyst;
A first valve opening calculation step of calculating a valve opening of a control valve capable of supplying the amount of reformed gas required for regeneration of the LNT catalyst from the reformer to the LNT catalyst from the LNT regeneration map according to the amount of NOx calculated from the NOx storage model; and ;
A valve opening correction step of receiving the amount of reformed gas and correcting the valve opening;
A valve operation step of operating the control valve according to the corrected valve opening degree;
Control method of a vehicle, characterized in that configured to further include. The method according to claim 2,
In the super control amount correction step
Correcting the target rotation speed of the supercharger by considering the valve opening corrected in the valve opening correction step together with the corrected target vane angle and the amount of reformed gas
Vehicle control method, characterized in that. The method according to claim 2,
In the super control amount correction step
Correcting the target rotation speed of the supercharger by considering the amount of EGR recycled to the engine together with the corrected target vane angle and the amount of reformed gas.
Vehicle control method, characterized in that. The method according to claim 2,
In the super control amount correction step
Correcting the target rotation speed of the supercharger by considering the valve opening corrected in the valve opening correction step and the amount of EGR recirculated to the engine together with the corrected target vane angle and the amount of reformed gas.
Vehicle control method, characterized in that. The method according to claim 1,
A collection amount calculation step of receiving a signal from the differential pressure sensor and calculating an amount of PM collected in the DPF from a collection amount model of the DPF;
A second valve opening degree calculating step of calculating a valve opening degree of a control valve capable of supplying an amount of reformed gas required for the DPF regeneration from the reformer to the DPF from the DPF regeneration map according to the PM amount calculated from the collection amount model;
A valve opening correction step of receiving the amount of reformed gas and correcting the valve opening;
A valve operation step of operating the control valve according to the corrected valve opening degree;
Control method of a vehicle, characterized in that configured to further include. The method of claim 6,
In the super control amount correction step
Correcting the target rotation speed of the supercharger by considering the valve opening corrected in the valve opening correction step together with the corrected target vane angle and the amount of reformed gas
Vehicle control method, characterized in that. The method of claim 6,
In the super control amount correction step
Correcting the target rotation speed of the supercharger by considering the amount of EGR recycled to the engine together with the corrected target vane angle and the amount of reformed gas.
Vehicle control method, characterized in that. The method of claim 6,
In the super control amount correction step
Correcting the target rotation speed of the supercharger by considering the valve opening corrected in the valve opening correction step and the amount of EGR recirculated to the engine together with the corrected target vane angle and the amount of reformed gas.
Vehicle control method, characterized in that. The method according to claim 1,
The driving mode includes a transient driving mode, a normal driving mode, an eco driving mode, a normal driving mode, a sports mode, a DPF regeneration mode, and a desulfurization mode;
The driving situation includes engine speed, accelerator pedal operation amount, change rate of accelerator pedal operation amount, engine intake air amount, intake air temperature, coolant temperature, vehicle speed.
Vehicle control method, characterized in that.

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