KR101703625B1 - System and method for controlling hybrid vehicle when lnt is regeneratated - Google Patents

Abstract

The present invention relates to a system and a method for controlling a hybrid vehicle when lean NOx trap (LNT) is regenerated. According to an embodiment of the present invention, the system for controlling a hybrid vehicle when LNT is regenerated comprises: an engine which generates driving force by combusting a fuel; a starting generator which starts the engine and selectively operates as a generator to produce electrical energy; a motor which assists the driving force of the engine and selectively operates as a generator to produce electrical energy; a battery which stores electrical energy produced by the starting generator and the motor; an engine clutch provided between the engine and a transmission; a lean NOx trap which purifies nitrogen oxide included in exhaust gas discharged from the engine; and a control unit which blocks power transferred to the engine by releasing coupling of the engine clutch when the vehicle is in overrun operation during LNT regeneration and regenerates the power output from the engine through the starting generator for braking.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a control system for a hybrid vehicle,

The present invention relates to a control apparatus and method for controlling a hybrid vehicle during regeneration of a linox trap, and more particularly, to a control apparatus and method for regeneration of a linox trap that regenerates nitrogen oxide contained in exhaust gas, And more particularly, to a control apparatus and method for controlling a hybrid vehicle when a knock trap is regenerated.

A hybrid vehicle is a vehicle that uses two or more power sources, and is generally driven using an engine and a motor. At this time, the engine to be used may be a gasoline engine or a diesel engine.

The hybrid vehicle can be formed in various structures using two or more power sources composed of an engine and a motor. The motor provided in the hybrid vehicle assists the power of the engine when accelerating or running backhill.

Generally, a hybrid vehicle equipped with a diesel engine has a low emission rate of CO and hydrocarbons as compared with a gasoline engine because the combustion is performed with a high air supply rate due to the characteristics of a diesel engine, Quot; NOx ") and particulate matter (PM).

In recent years, a lean NOx trap (LNT) has been used to purify such nitrogen oxides. When the engine air-fuel ratio is operated in a lean atmosphere, the nitrogen oxide trap contained in the exhaust gas is adsorbed. When the air-fuel ratio of the engine is operated in a rich atmosphere, the adsorbed nitrogen oxide is desorbed, Thereby reducing the nitrogen oxide contained in the exhaust gas and the nitrogen oxide contained in the exhaust gas.

The removed nitrogen oxides are stored in the form of sulfur compounds in the linox trap. The sulfur compounds stored in the nitrogen oxide purification apparatus deteriorate the nitrogen oxide purification performance and must be periodically removed. Removing the sulfur compounds formed in the linox trap is referred to as " regeneration ".

In order to regenerate the nitrogen oxide, the engine must maintain constant regeneration conditions. For example, the engine RPM must be within the set number of revolutions, and the engine torque should be within the set torque. If the linox trap is reproduced, if the reproduction condition is exceeded, the reproduction efficiency is lowered, and the reproduction frequency and the reproduction time are increased.

Further, when regenerating the linox trap, the exhaust gas must be in a rich state.

However, when playing the Linnox trap, when the vehicle enters the overrun section (the vehicle is in the off-road state or the braking state), the engine does not inject fuel, so the exhaust gas does not maintain the rich state. It can not be done.

The matters described in the background section are intended to enhance the understanding of the background of the invention and may include matters not previously known to those skilled in the art.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a hybrid vehicle which is capable of improving the regeneration efficiency and improving the fuel efficiency of a vehicle when regenerating a linox trap for purifying nitrogen oxide contained in exhaust gas, An object of the present invention is to provide a vehicle control apparatus and method.

According to an aspect of the present invention, there is provided a control apparatus for a hybrid vehicle, including: an engine for generating a driving force by burning fuel; A starter generator for starting said engine and optionally acting as a generator to generate electrical energy; A drive motor that assists the driving force of the engine and selectively operates as a generator to generate electric energy; A battery for storing electrical energy generated by the starting generator and the driving motor; An engine clutch provided between the engine and the transmission; A linox trap for purifying nitrogen oxides contained in the exhaust gas discharged from the engine; And stopping the engagement of the engine clutch to shut off the power transmitted to the wheel from the engine when the vehicle is in a state of a driving state, a braking state, or a stationary state when the linox trap is regenerated, And a regenerative braking unit that regeneratively brakes the engine.

The control unit may operate the engine operating point to a level that is smaller than the maximum power generation amount of the starter generator when the SOC (state of charge) of the battery is greater than a set value.

The controller may operate the engine operating point at a level corresponding to a maximum power generation amount of the starter generator if the SOC (state of charge) of the battery is less than the set value.

According to another aspect of the present invention, there is provided a control method for a hybrid vehicle, the method comprising: determining whether a condition for regenerating a linox trap is satisfied; Determining whether the vehicle is in a power running state, a braking state, or a stop state; Releasing the engagement of the engine clutch provided between the engine and the transmission when the regeneration condition of the linox trap is satisfied and the vehicle is in a state of running, braking, or stopping; Adjusting the output torque of the engine according to the SOC of the battery; And regeneratively braking the output torque of the engine through the starting generator.

If the state of charge of the battery is equal to or greater than a set value, the output torque of the engine can be reduced to a level smaller than a maximum power generation amount of the starter generator.

If the SOC (state of charge) of the battery is smaller than the set value, the output torque of the engine can be operated at a level corresponding to the maximum power generation amount of the starter generator.

According to the control apparatus and method for controlling the hybrid vehicle according to the embodiment of the present invention as described above, when the vehicle is in the driving state, the braking state, or the stopped state when the linox trap is reproduced, The linox trap can be smoothly reproduced.

Further, by regenerating the torque output from the engine through the starter generator during the regeneration of the linox trap, the fuel consumption of the vehicle can be improved.

These drawings are for the purpose of describing an exemplary embodiment of the present invention, and therefore the technical idea of the present invention should not be construed as being limited to the accompanying drawings.
FIG. 1 is a conceptual diagram showing a configuration of a control apparatus for a hybrid vehicle according to an embodiment of the present invention.
2 is a conceptual diagram showing a configuration of an engine system according to an embodiment of the present invention.
3 is a graph showing the relationship between the APS, the clutch state, the engine speed, the engine torque, and the starting generator torque according to the embodiment of the present invention.
FIG. 4 is a flowchart illustrating a control method of a hybrid vehicle according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which: FIG. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. .

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a control apparatus for a hybrid vehicle according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, in the regeneration of the linox trap according to the embodiment of the present invention, the control apparatus for the hybrid vehicle includes an engine 10 for generating a driving force by burning fuel, , A drive motor (50) that assists the driving force of the engine (10) and selectively operates as a generator to generate electric energy, a generator (20) A battery 80 for storing the electric energy generated by the motor 50, an engine clutch 30 provided between the engine 10 and the transmission 40, A linox trap 100 for purifying nitrogen oxides and a control unit 90 for controlling the engine 10, the starting generator 20, the driving motor 50 and the linox trap 100 .

The engine 10 burns fuel to generate a driving force, and the generated driving force is provided to the front wheel of the vehicle.

An engine clutch 30 and a transmission 40 are sequentially provided between the engine 10 and the front wheels. The engine clutch 30 is operated under the control of the controller 90 and the driving force generated by the engine 10 is selectively provided to the front wheels in accordance with the engagement and disengagement of the engine clutch 30. [ The transmission 40 changes the driving force generated in the engine 10 to a required rotational force according to the speed of the vehicle according to the running state of the vehicle, and supplies the rotational force to the front wheel.

The starter generator 20 operates as a starter and a generator. That is, the engine starts according to a control signal applied from the controller 90, and operates as a generator to generate electric energy when the engine 10 maintains the start-up state. The electric energy generated by the starter generator 20 is charged in the battery 80 provided in the hybrid vehicle. The starter generator 20 may also be referred to as an integrated starter and generator (ISG) or a hybrid starter and generator (HSG).

The driving motor 50 receives electric energy from the battery 80 to provide a driving force to the rear wheel of the vehicle, and assists the driving force of the engine 10 when the hybrid vehicle is running. For example, the driving performance of the vehicle is improved by assisting the driving force of the engine 10 at the time of rapid acceleration of the vehicle or during back plate running. The drive motor 50 operates as a generator at the time of braking or driving the vehicle to generate electric energy, and the generated electric energy is charged into the battery 80.

A speed reducer (60) and a motor clutch (70) are provided between the drive motor (50) and the rear wheel. The speed reducer 60 converts the driving force generated by the driving motor 50 into a necessary rotational force and supplies the driving force to the rear wheel.

The motor clutch 70 is operated under the control of the controller 90 and the driving force generated by the driving motor 50 is selectively provided to the rear wheel in accordance with the engagement and disengagement of the motor clutch 70.

In this way, the hybrid vehicle is provided with the driving force generated by the engine 10 on the front wheels and the driving force generated by the driving motor 50 on the rear wheels, which is referred to as a through the road (TTR) system.

The embodiment of the present invention will be described taking the hybrid vehicle of the TTR scheme as an example. However, the scope of the present invention is not limited thereto, and it goes without saying that the present invention can be applied to other types of hybrid vehicles.

The control unit 90 controls operations of the engine 10, the engine clutch 30, the starter generator 20, the drive motor 50 and the motor clutch 70, and the control unit 90 May be provided with one or more processors operating according to the set program, and the set program is adapted to perform each step of the control method of the hybrid vehicle according to the embodiment of the present invention.

The control unit 90 may be an electronic control unit (ECU) and / or a hybrid control unit (HCU) provided in the vehicle, and may be an ECU and an HCU.

The exhaust pipe through which the exhaust gas discharged from the engine 10 flows is provided with a linox trap 100 for purifying the nitrogen oxide contained in the exhaust gas. The nitrogen oxides removed through the linox trap (100) are stored in the linox trap (100) in the form of sulfur compounds.

The control unit 90 calculates a target engine torque for regeneration of the linox trap 100 and controls the engine torque. When regenerating the linox trap 100, a constant engine torque must be maintained.

When the linox trap 100 is regenerated, the exhaust gas discharged from the engine 10 can not maintain a rich state when the vehicle is in a running state, a braking state, or a stopped state. Therefore, the regeneration of the linox trap 100 is frequently performed or the regeneration time is increased, and the efficiency of purifying the exhaust gas is decreased.

In order to solve such a problem, the control unit 90 releases the engagement of the engine clutch 30 when the vehicle is in the power running state, the braking state, or the stop state when the linox trap 100 is reproduced, Disconnect the transmitted power. And, the engine is operated so that the engine torque is maintained at a constant level so that the exhaust gas is rich.

Whether or not the vehicle is in the power running state, the braking state, or the stopping state can be regarded as the vehicle overrun if the opening amount of the APS (acceleration pedal sesnsor) is "0 ". That is, when the driver does not step on the accelerator pedal at all, it can be judged that the vehicle is in a running state of a vehicle, a braking state, or a stopped state.

The power output from the engine 10 is regeneratively braked through the starter generator 20, thereby recovering the power output from the engine 10.

Specifically, the controller 90 controls the engine torque according to a state of charge (SOC) of the battery 80.

That is, if the SOC (state of charge) of the battery 80 is equal to or greater than a set value (for example, 70%), the output torque of the engine is reduced to a level smaller than the maximum power generation amount of the starter generator 20. If the state of charge of the battery 80 is smaller than the preset value, the output torque of the engine is operated at a level corresponding to the maximum power generation amount of the starter generator 20.

Here, the operation of reducing the output torque of the engine to a certain level means that the engine speed and the engine torque are reduced to a certain level as compared with the general case.

When the SOC of the battery 80 is high (the SOC of the battery 80 is equal to or higher than the set value), the engine torque is outputted at a level corresponding to the maximum power generation amount of the starter generator 20, It may become too high. Since the durability of the battery 80 deteriorates when the SOC of the battery 80 becomes too high, the engine torque is reduced to a level smaller than the maximum amount of charge of the starter generator 20, thereby preventing the SOC of the battery 80 from becoming too high can do.

If the SOC of the battery 80 is low (SOC of the battery 80 is smaller than the set value), the engine 80 is operated at a level corresponding to the maximum power generation amount of the starter generator 20, The SOC of the battery 80 can be maintained at an appropriate level, and the durability of the battery 80 can be maintained.

Hereinafter, a method of a control apparatus for a hybrid vehicle in regeneration of the linox trap 100 according to an embodiment of the present invention will be described in detail.

3 is a graph showing the relationship between the APS, the clutch state, the engine speed, the engine torque, and the starting generator torque according to the embodiment of the present invention. FIG. 4 is a flowchart illustrating a control method of a hybrid vehicle according to an embodiment of the present invention.

Referring to FIGS. 3 and 4, the controller 90 determines whether the condition for reproducing the linox trap 100 is satisfied (S10). The regeneration condition of the linox trap 100 can be judged as satisfying the regeneration condition if the running distance of the vehicle satisfies a certain running distance.

The control unit 90 determines whether the vehicle is in a driving state, a braking state, or a stopped state based on the opening amount of the APS (S20). At this time, whether or not the vehicle is in the power running state, the braking state, or the stopping state can be determined that the vehicle is in the power running state, the braking state, or the stopping state when the opening amount of the APS is "0 "

If the regeneration condition of the linox trap 100 is satisfied and the vehicle is in the driving state of the vehicle, the braking state, or the stopped state, the controller 90 controls the engine 10 and the transmission 40, which are provided between the engine 10 and the transmission 40, The engagement of the clutch 30 is released (see Fig. 3B) (S30), and the power generated in the engine 10 is prevented from being transmitted to the wheel (front wheel).

The control unit 90 determines the SOC of the battery 80 in step S40 and adjusts the output torque of the engine in accordance with the SOC of the battery 80. [

Specifically, if the state of charge of the battery 80 is equal to or greater than a set value, the controller 90 lowers the output torque of the engine by a predetermined level less than the maximum power generation amount of the starter generator 20 (S42) (See Figs. 3C and 3D).

The torque output from the engine 10 is regeneratively braked through the starter generator 20 (S50) (see FIG. 3E).

If the state of charge of the battery 80 is less than the set value in step S40, the controller 90 sets the output torque of the engine to a value corresponding to the maximum power generation amount of the starter generator 20 (S44).

Then, the output torque of the engine 10 is regeneratively braked through the starter generator 20 (S50) (see Fig. 3E).

As described above, according to the control apparatus and method of the hybrid vehicle during the regeneration of the linox trap 100 according to the embodiment of the present invention, when the linox trap 100 is regenerated, , It is possible to maintain the rich state of the exhaust gas by outputting the engine torque at a certain level, thereby smoothly regenerating the linox trap 100.

At this time, the output torque of the engine 10 is regeneratively braked through the starter generator 20, so that the fuel economy of the vehicle can be improved.

By adjusting the torque of the engine in accordance with the SOC of the battery 80, the SOC of the battery 80 can be maintained at an appropriate level and the durability of the battery 80 can be improved.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, And it goes without saying that the invention belongs to the scope of the invention.

10: Engine
20: starter generator
30: Engine clutch
40: transmission
50: drive motor
60: Reducer
70: Motor clutch
80: Battery
90:
100: Linnox Trap

Claims (6)

An engine for generating a driving force by burning fuel;
A starter generator for starting said engine and optionally acting as a generator to generate electrical energy;
A drive motor that assists the driving force of the engine and selectively operates as a generator to generate electric energy;
A battery for storing electrical energy generated by the starting generator and the driving motor;
An engine clutch provided between the engine and the transmission;
A linox trap for purifying nitrogen oxides contained in the exhaust gas discharged from the engine; And
When the vehicle is in a driving state, a braking state, or a stop state when the vehicle is in the driving state, the engine clutch is disengaged to cut off the power transmitted to the wheel from the engine, and the power output from the engine is transmitted to the starting generator A control unit for regeneratively braking the vehicle;
And a controller for controlling the hybrid vehicle. The method according to claim 1,
The control unit
If the SOC (state of charge) of the battery is equal to or greater than a set value,
Wherein the engine operating point is operated to be smaller than a maximum power generation amount of the starter generator by a predetermined level. The method according to claim 1,
The control unit
If the SOC (state of charge) of the battery is less than the set value,
Wherein the engine operating point is operated at a level corresponding to a maximum power generation amount of the starter generator. Determining whether the regeneration condition of the linox trap is satisfied;
Determining whether the vehicle is in a power running state, a braking state, or a stop state;
Releasing the engagement of the engine clutch provided between the engine and the transmission when the regeneration condition of the linox trap is satisfied and the vehicle is in a state of running, braking, or stopping;
Adjusting the output torque of the engine according to the SOC of the battery; And
Regenerating an output torque of the engine through a starting generator;
And a control unit for controlling the hybrid vehicle. 5. The method of claim 4,
If the SOC (state of charge) of the battery is equal to or greater than a set value,
Wherein the output torque of the engine is lower than a maximum power generation amount of the starter generator by a predetermined amount. 5. The method of claim 4,
If the SOC (state of charge) of the battery is less than the set value,
Wherein the output torque of the engine is operated at a level corresponding to a maximum power generation amount of the starter generator.

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