KR102212791B1 - Apparatus for controlling mild hybrid electric vehicle - Google Patents

Abstract

Disclosed are a mild hybrid vehicle control device and a method thereof. The mild hybrid vehicle control device of the present invention comprises: a mild hybrid starter & generator (MHSG) which starts an engine or generates power by an output of the engine; a setting SOC sensor of a high voltage battery which detects a state of charge (SOC) of the high voltage battery; a setting SOC sensor of a low voltage battery which detects an SOC of the low voltage battery; an accelerator pedal sensor for detecting the position of an accelerator pedal; and a control unit which detects a target speed based on the position of the accelerator pedal according to the SOC of the low voltage battery and the SOC of the high voltage battery in a limp-home mode due to a failure of an electric throttle control (ETC) system, and controls output torque of the engine and charge and discharge torque of the MHSG according to the detected target speed to control the speed of a vehicle.

Description

Mild hybrid vehicle control device {APPARATUS FOR CONTROLLING MILD HYBRID ELECTRIC VEHICLE}

The present invention relates to an apparatus for controlling a mild hybrid vehicle, and more particularly, a mild hybrid vehicle capable of controlling the vehicle speed of a mild hybrid vehicle according to a state of charge (SOC) of a high voltage battery and a low voltage battery even in a limp home mode. It relates to a control device.

A mild hybrid vehicle is equipped with a Mild Hybrid Starter & Generator (MHSG) that starts an engine or generates power based on the output of the engine instead of an alternator. In the hard-type hybrid vehicle, a starting generator that starts an engine or generates power by an output of the engine and a drive motor that drives the vehicle are separately provided.

Mild hybrid vehicles do not have a driving mode that drives the vehicle with only the torque of MHSG, but MHSG can be used to assist the engine torque according to the driving condition, and the battery (for example, 48V battery) can be charged through regenerative braking. have. Accordingly, the fuel economy of the mild hybrid vehicle can be improved.

In order to electronically control the amount of air flowing into the engine, an Electric Throttle Control (ETC) system is used. When it is determined that the ETC system is in a faulty state, it enters the Limp-Home Mode and allows the vehicle to move to a repair shop with minimal driving performance that can avoid road hazards. When entering the lymph groove mode, the opening amount of the throttle valve is fixed to the set opening amount.

The background technology of the present invention is disclosed in Korean Patent Publication No. 10-1724491 (2017.04.03) in'a driving control apparatus and method for a mild hybrid vehicle'.

The conventional mild hybrid vehicle is the same as the conventional conventional vehicle in the limp home mode, and the engine output torque is used for the vehicle driving power except for the minimum amount required for battery charging.Therefore, it is difficult to secure the driving performance of the vehicle in the limp home mode. there was.

The present invention was invented to improve the above-described problem, and an object according to an aspect of the present invention is to control the vehicle speed of a mild hybrid vehicle according to the state of charge (SOC) of each of the high voltage battery and the low voltage battery even in the limp home mode. It is to provide a mild hybrid vehicle control device.

An apparatus for controlling a mild hybrid vehicle according to an aspect of the present invention includes: a Mild Hybrid Starter & Generator (MHSG) that starts an engine or generates power by an engine output; A high voltage battery SOC sensor for sensing a state of charge (SOC) of the high voltage battery; A low voltage battery SOC sensor for detecting SOC of the low voltage battery; An accelerator pedal sensor that senses the position of the accelerator pedal; And in a limp home mode due to a failure of the Electric Throttle Control (ETC) system, a target speed is detected based on the position of the accelerator pedal according to the SOC of the low voltage battery and the SOC of the high voltage battery, and the target speed is detected according to the detected target speed. It characterized in that it comprises a control unit for controlling the speed of the vehicle by controlling the output torque of the engine and the charge and discharge torque of the MHSG.

The control unit of the present invention provides a target speed based on the position of the accelerator pedal according to whether the SOC of the low voltage battery is greater than or equal to a preset SOC of the low voltage battery and whether the SOC of the high voltage battery is greater than or equal to the preset SOC of the high voltage battery. It characterized in that it detects.

The control unit of the present invention charges the low voltage battery if the SOC of the low voltage battery is less than the set SOC of the low voltage battery, and charges the high voltage battery if the SOC of the high voltage battery is less than the set SOC of the high voltage battery. do.

The control unit of the present invention is characterized in that the high voltage battery charges the low voltage battery with the high voltage battery when the low voltage battery can be charged by the amount of power consumption of the low voltage battery.

The control unit of the present invention is characterized in that when the high voltage battery cannot charge the low voltage battery as much as the power consumption of the low voltage battery, the low voltage battery is charged by using the output torque of the engine after the vehicle is stopped.

The control unit of the present invention is characterized in that when the SOC of the high voltage battery is less than the set SOC of the high voltage battery, the high voltage battery is charged by using the output torque of the engine after the vehicle is stopped.

The mild hybrid vehicle control apparatus according to an aspect of the present invention is capable of controlling the vehicle speed of the mild hybrid vehicle according to the state of charge (SOC) of each of the high voltage battery and the low voltage battery in the limp home mode, thereby securing driving performance of the vehicle. Make it possible.

1 is a block diagram of a mild hybrid vehicle according to an embodiment of the present invention.
2 is a block diagram of an apparatus for controlling a mild hybrid vehicle according to an embodiment of the present invention.
3 is a flowchart of a method for controlling a mild hybrid vehicle according to an embodiment of the present invention.

Hereinafter, an apparatus for controlling a mild hybrid vehicle according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In this process, thicknesses of lines or sizes of components shown in the drawings may be exaggerated for clarity and convenience of description. In addition, terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to the intention or custom of users or operators. Therefore, definitions of these terms should be made based on the contents throughout the present specification.

The implementation described herein may be implemented in, for example, a method or process, an apparatus, a software program, a data stream or a signal. Although discussed only in the context of a single form of implementation (eg, only as a method), the implementation of the discussed features may also be implemented in other forms (eg, an apparatus or program). The device may be implemented with appropriate hardware, software and firmware. The method may be implemented in an apparatus such as a processor, which generally refers to a processing device including, for example, a computer, microprocessor, integrated circuit or programmable logic device, or the like. Processors also include communication devices such as computers, cell phones, personal digital assistants (“PDAs”) and other devices that facilitate communication of information between end-users.

1 is a block diagram of a mild hybrid vehicle according to an embodiment of the present invention.

Referring to FIG. 1, a mild hybrid vehicle according to an embodiment of the present invention includes an engine 10, a transmission 20, a Mild Hybrid Starter & Generator (MHSG) 50, a high voltage battery 70, and a converter 90. , A low voltage battery 80, and an electric throttle control (ETC) system 110.

The engine 10 converts chemical energy into mechanical energy by burning fuel and air. The engine 10 may include a plurality of combustion chambers into which fuel and air are introduced, an ignition device for igniting fuel and air introduced into the combustion chamber, and an injector for injecting fuel.

The transmission 20 receives torque from the engine 10 through an input shaft and transmits it to a differential gear device (not shown) through an output shaft.

The ETC system 110 controls the flow of air supplied to the intake manifold. The ETC system 110 is disposed in an intake line formed to supply air to the intake manifold.

The MHSG 50 converts electrical energy into mechanical energy or converts mechanical energy into electrical energy. That is, the MHSG 50 may start the engine 10 or generate power by the output of the engine 10. Further, the MHSG 50 may assist the torque of the engine 10.

The mild hybrid vehicle may use the torque of the MHSG 50 as an auxiliary power while the combustion torque of the engine 10 is used as the main power. The engine 10 and the MHSG 50 may be connected through a belt 60.

The high voltage battery 70 may be charged by supplying electricity to the MHSG 50 or through electricity recovered through the MHSG 50 in a battery charging mode, for example, a regenerative braking mode. The high voltage battery 70 may be a 48V lithium-ion battery.

The low voltage battery 80 may be a 12V battery. The low voltage battery 80 supplies power to an electric load using a low voltage.

The electric load may include all various electric and electronic devices using power from the low voltage battery 80 such as a headlamp, air conditioner, wiper, and the like.

The converter 90 charges the low voltage battery 80 by converting the high voltage supplied from the high voltage battery 70 into a low voltage. As the converter 90, a low voltage DC-DC converter (LDC) may be employed.

2 is a block diagram of an apparatus for controlling a mild hybrid vehicle according to an embodiment of the present invention.

2, the mild hybrid vehicle control apparatus according to an embodiment of the present invention includes an ETC system 110, a high voltage battery SOC sensor 120, a low voltage battery SOC sensor 130, an accelerator pedal sensor 140, and a vehicle speed. A sensor 150, a shift stage sensor 160, an MHSG 50, an engine 10, an output unit 170, and a control unit 180 are included.

The high voltage battery SOC sensor 120 detects the SOC of the high voltage battery 70.

The low voltage battery SOC sensor 1300 detects the SOC of the low voltage battery 80.

The accelerator pedal sensor 140 detects the position of the accelerator pedal. When the accelerator pedal is fully depressed, the accelerator pedal position value is 100%, and when the accelerator pedal is not depressed at all, the accelerator pedal position value is 0%. Accordingly, the position value of the accelerator pedal sensed by the accelerator pedal sensor 140 is within the range of 0% to 100%.

The vehicle speed sensor 150 detects the speed of the mild hybrid vehicle. The vehicle speed sensor 150 may detect a speed using a wheel speed sensor installed on each wheel of a vehicle. In addition, the vehicle speed sensor 150 may be a GPS system.

The shift stage sensor 160 detects the shift stage of the mild hybrid vehicle.

The output unit 170 requests the driver to stop the vehicle when charging the high voltage battery 70 or the low voltage battery 80. A vehicle cluster may be employed as the output unit 170. For example, the output unit 170 requests the driver to change to the P or N gear after stopping the vehicle.

The controller 180 detects the target speed based on the position of the accelerator pedal according to the SOC of the low voltage battery 80 and the SOC of the high voltage battery 70 in the limp home mode due to a failure of the ETC system 110 and detects the target speed. According to this, the output torque of the engine 10 and the charge/discharge torque of the MHSG 50 are controlled to control the speed of the vehicle.

In more detail, the controller 180 determines whether the ETC system 110 has failed. The controller 180 determines whether the ETC system 110 has failed through a failure of a throttle valve (not shown), an ETC motor (not shown), or a throttle position sensor (not shown) in the ETC system 110.

When it is determined that the ETC system 110 is in a faulty state, the controller 180 enters the lymphatic home mode.

When entering the lymphatic home mode, the controller 180 detects the SOC of the low voltage battery 80 using the low voltage battery SOC sensor 130.

Subsequently, the controller 180 compares the detected SOC of the low voltage battery 80 with a preset SOC of the low voltage battery 80 and determines whether the SOC of the low voltage battery 80 is greater than or equal to the set SOC of the low voltage battery 80 .

The setting SOC of the low voltage battery 80 is the minimum SOC of the low voltage battery 80 for performing the operation of the mild hybrid vehicle.

Meanwhile, in order for the mild hybrid vehicle to perform a basic operation in the limp home mode, the amount of charge of the low voltage battery 80 must be secured first. Here, the driver's willingness to accelerate may be reflected through control of the charge amount of the battery. For example, when the driver is not willing to accelerate, the controller 180 allows the vehicle speed to be maintained while increasing the amount of charge through the MHSG 50. On the other hand, when the driver is willing to accelerate, the controller 180 may increase the vehicle speed by starting the engine with the MHSG 50 while reducing the amount of charge or increasing the amount of discharge through the MHSG 50.

When the SOC of the low voltage battery 80 is equal to or greater than the set SOC of the low voltage battery 80, the controller 180 controls the high voltage battery SOC sensor 120 to detect the SOC of the high voltage battery 70.

Subsequently, the controller 180 determines whether the SOC of the high voltage battery 70 is greater than or equal to the set SOC of the high voltage battery 70.

The setting SOC of the high voltage battery 70 is the minimum voltage of the high voltage battery 70 for performing the operation of the mild hybrid vehicle.

If the SOC of the high voltage battery 70 is equal to or greater than the set SOC of the high voltage battery 70, the controller 180 detects the position of the accelerator pedal through the accelerator pedal sensor 140, and based on the detected position of the accelerator pedal, The target speed is detected.

Subsequently, the controller 180 controls the output torque of the engine 10 and the charge/discharge torque of the MHSG 50 according to the detected target speed to adjust the speed of the vehicle. In this case, the controller 180 controls the MHSG 50 to implement the target speed (Proportional-Integral) (PI).

That is, the controller 180 receives feedback on the vehicle speed sensed by the vehicle speed sensor 150 and controls PI on whether the engine 10 is fuel cut, ignition timing, and the amount of charge of the MHSG 50. The vehicle speed is controlled to reach the target vehicle speed through.

In the limp home mode, since the ETC system 110 is in a failure state, it is practically difficult to control the engine output. However, the amount of filling can be controlled flexibly through the MHSG 50.

For example, when the driver presses the accelerator pedal to the maximum, the controller 180 sets the engine ignition timing to the maximum advance state for the amount of air supplied to the cylinder in the engine through the fixed throttle valve, and thus the maximum speed can be realized even in the limp home mode. have.

In addition, when the driver does not step on the accelerator pedal, the controller 180 may control the MHSG 50 to charge the high voltage battery 70 or the low voltage battery 80 in the generation mode.

On the other hand, if the SOC of the low voltage battery 80 is less than the set SOC of the low voltage battery 80 in the above process, the controller 180 uses the high voltage battery 70 to reduce the power consumption of the low voltage battery 80 to the low voltage battery 80 It determines whether charging is possible, and charges the low voltage battery 80 according to the determination result.

In this case, if the low voltage battery 80 cannot be charged by the high voltage battery 70 as much as the power consumption of the low voltage battery 80 or the SOC of the high voltage battery 70 is less than the set SOC of the high voltage battery 70, the controller 180 Is requested to stop the vehicle from the driver through the output unit 170, and then, when the shift stage sensor 160 detects that the shift stage of the vehicle is the P stage or the N stage, the high voltage battery 70 is controlled by controlling the MHSG 50. Alternatively, the low voltage battery 80 is charged.

The functions of the above-described components have been separately described so that the operation of the present embodiment can be more clearly understood. However, depending on the embodiment, the controller 180 integrates all the functions of the components, or Note that the controller 180 may replace at least one or more of the functions of the constituent elements.

Hereinafter, a method for controlling a mild hybrid vehicle according to an embodiment of the present invention will be described in detail with reference to FIG. 3.

3 is a flowchart of a method for controlling a mild hybrid vehicle according to an embodiment of the present invention.

Referring to FIG. 3, the controller 180 determines whether the ETC system 110 has failed through a failure of a throttle valve, an ETC motor, or a throttle position sensor in the ETC system 110 (S10).

If it is determined that the ETC system 110 is in a faulty state as a result of the determination in step S10, the controller 180 enters the lymphatic home mode (S20).

Upon entering the lymphatic home mode, the controller 180 detects the SOC of the low voltage battery 80 using the low voltage battery SOC sensor 130, and determines the SOC of the low voltage battery 80 to the preset low voltage battery 80. Compared with the set SOC, it is determined whether the SOC of the low voltage battery 80 is equal to or greater than the set SOC of the low voltage battery 80 (S30).

As a result of the determination in step S30, if the SOC of the low voltage battery 80 is greater than or equal to the set SOC of the low voltage battery 80, the controller 180 controls the high voltage battery SOC sensor 120 to detect the SOC of the high voltage battery 70 , It is determined whether the SOC of the high voltage battery 70 is equal to or greater than the set SOC of the high voltage battery 70 (S40).

As a result of the determination in step S40, if the SOC of the high voltage battery 70 is equal to or greater than the set SOC of the high voltage battery 70, the controller 180 detects the position of the accelerator pedal through the accelerator pedal sensor 140 and detects the accelerator pedal. The target speed of the vehicle is detected based on the position of (S50).

Subsequently, the controller 180 controls the output torque of the engine 10 and the charge/discharge torque of the MHSG 50 according to the detected target speed to adjust the speed of the vehicle (S60).

For example, when the driver presses the accelerator pedal to the maximum, the controller 180 sets the engine ignition timing to the maximum advance state before the failure, and implements the maximum speed even in the limp home mode. If the driver does not press the accelerator pedal, the controller 180 ) Keeps the ignition timing with at least reserve torque.

On the other hand, as a result of the determination in step S30, if the SOC of the low voltage battery 80 is less than the set SOC of the low voltage battery 80, the controller 180 controls the high voltage battery SOC sensor 120 to determine the SOC of the high voltage battery 70. To detect.

Subsequently, the controller 180 determines whether the high voltage battery 70 can charge the low voltage battery 80 more than the power consumption amount (S70), and as a result of the determination, the high voltage battery 70 charges the low voltage battery 80 more than the power consumption amount. If this is possible, the controller 180 charges the low voltage battery 80 with the high voltage battery 70 so that the high voltage battery 70 can assist the power of the low voltage battery 80 (S80).

After charging the low voltage battery 80 with the high voltage battery 70 as described above, the controller 180 determines whether the SOC of the high voltage battery 70 is equal to or greater than the set SOC of the high voltage battery 70 (S40). As a result of the determination, if the SOC of the high voltage battery 70 is less than the set SOC of the high voltage battery 70, the controller 180 charges the high voltage battery 70. This will be described later.

On the other hand, as a result of the determination in step S70, if the high voltage battery 70 cannot be charged more than the power consumption of the low voltage battery 80, the controller 180 charges the low voltage battery 80.

That is, as a result of the determination in step S70, the SOC of the high-voltage battery 70 is less than the set SOC of the high-voltage battery 70, or the determination result in step S40 is that the high-voltage battery 70 is charged more than the power consumption of the low-voltage battery 80. If it is impossible, the controller 180 charges the low voltage battery 80 or the high voltage battery 70.

To this end, first, the controller 180 requests the driver to stop the vehicle through the output unit 170 (S90). That is, the controller 180 outputs a message informing the driver that the battery needs to be charged through the output unit 170, and requests the shifting stage of the transmission 20 to be shifted to the P-speed or the N-speed after the vehicle stops.

Thereafter, the controller 180 determines whether the position value of the accelerator pedal sensed by the accelerator pedal sensor 140 is 0, and whether the shift stage sensed through the shift stage sensor 160 is the P or N stage (S100). ).

As a result of the determination in step S100, if the vehicle speed is 0 km/h and the shift stage sensed through the shift stage sensor 160 is P or N, the controller 180 cancels requesting the P or N shift. After (S110), the high voltage battery 70 or the low voltage battery 80 is charged using the engine output torque (S120). On the other hand, if the vehicle speed is 0 km/h as a result of the determination in step S100, if the shift stage detected by the shift stage sensor 160 is not the P stage or the N stage, the output unit 170 indicates that the driver needs to charge the battery. A message instructing is output, and a request is made to shift the shift stage of the transmission 20 to the P or N stage after the vehicle stops.

That is, the controller 180 drives the MHSG 50 through the engine output torque to charge the high voltage battery 70 or converts the high voltage charged in the high voltage battery 70 to a low voltage through the converter 90 The low voltage battery 80 is charged by applying it to the battery 80.

As described above, in the limp home mode according to an embodiment of the present invention, the vehicle speed of the mild hybrid vehicle can be controlled according to the state of charge (SOC) of each of the high voltage battery 70 and the low voltage battery 80, thereby improving the driving performance of the vehicle. To secure it.

The present invention has been described with reference to the embodiments shown in the drawings, but these are only exemplary, and those of ordinary skill in the art to which the present technology pertains, various modifications and other equivalent embodiments are possible. I will understand. Therefore, the true technical protection scope of the present invention should be determined by the following claims.

10: engine 20: transmission
50: MHSG 70: high voltage battery
80: low voltage battery 90: converter
110: ETC system 120: high voltage battery SOC sensor
130: low voltage battery SOC sensor 140: accelerator pedal sensor
150: vehicle speed sensor 160: shift stage sensor
170: output unit 180: control unit

Claims (6)

MHSG (Mild Hybrid Starter & Generator) that starts the engine or generates power by the engine output;
A high voltage battery SOC sensor for sensing a state of charge (SOC) of the high voltage battery;
A low voltage battery SOC sensor for detecting SOC of the low voltage battery;
An accelerator pedal sensor that senses the position of the accelerator pedal; And
In the limp home mode due to a failure of the Electric Throttle Control (ETC) system, a target speed is detected based on the position of the accelerator pedal according to the SOC of the low voltage battery and the SOC of the high voltage battery, and the engine according to the detected target speed And a control unit that controls the output torque of the MHSG and the charge/discharge torque of the MHSG to adjust the speed of the vehicle,
When the SOC of the low voltage battery is less than the set SOC of the low voltage battery and the high voltage battery cannot charge the low voltage battery as much as the power consumption of the low voltage battery, the control unit uses the output torque of the engine after stopping the vehicle. Mild hybrid vehicle control device, characterized in that charging the low voltage battery.
The method of claim 1, wherein the control unit
The target speed is detected based on the position of the accelerator pedal according to whether the SOC of the low voltage battery is greater than or equal to the set SOC of the low voltage battery and whether the SOC of the high voltage battery is greater than or equal to the preset SOC of the high voltage battery. Mild hybrid vehicle control unit.
The method of claim 2, wherein the control unit
When the SOC of the low voltage battery is less than the set SOC of the low voltage battery, the low voltage battery is charged, and when the SOC of the high voltage battery is less than the set SOC of the high voltage battery, the high voltage battery is charged. .
The method of claim 3, wherein the control unit
And charging the low voltage battery with the high voltage battery when the high voltage battery can charge the low voltage battery by the amount of power consumption of the low voltage battery.
The method of claim 3, wherein the control unit
When the SOC of the high voltage battery is less than the set SOC of the high voltage battery, the high voltage battery is charged using the output torque of the engine after the vehicle is stopped.
MHSG (Mild Hybrid Starter & Generator) that starts the engine or generates power by the engine output;
A high voltage battery SOC sensor for detecting a state of charge (SOC) of the high voltage battery;
A low voltage battery SOC sensor for detecting SOC of the low voltage battery;
An accelerator pedal sensor that senses the position of the accelerator pedal; And
In the limp home mode due to a failure of the Electric Throttle Control (ETC) system, a target speed is detected based on the position of the accelerator pedal according to the SOC of the low voltage battery and the SOC of the high voltage battery, and the engine according to the detected target speed And a control unit that controls the output torque of the MHSG and the charge/discharge torque of the MHSG to adjust the speed of the vehicle,
The control unit, when the SOC of the high voltage battery is less than a preset SOC of the high voltage battery, charging the high voltage battery using the output torque of the engine after the vehicle is stopped.

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