KR102153325B1 - Apparatus for controlling engine start of hybrid electric vehicle and method thereof - Google Patents

Abstract

The present invention relates to an engine start control apparatus for a hybrid vehicle and a method thereof. The engine start control apparatus for a hybrid vehicle includes: a one-way clutch interposed between an engine and a motor; a vehicle state input part receiving state information of a vehicle; an engine driving part driving the engine; a UD clutch driving part regulating the rotation force of an input shaft by controlling a UD clutch of a transmission; and a control part receiving the state information of the vehicle from the vehicle state input part to start the engine by controlling the engine driving part if the state information satisfies an engine start condition, while starting the engine after neutralizing the transmission by controlling the UD clutch driving part if the rpm of the input shaft is less than a set rpm. Therefore, the engine start control apparatus is capable of reducing the number of components, production costs and weight.

Description

Engine start control device of hybrid vehicle and its method {APPARATUS FOR CONTROLLING ENGINE START OF HYBRID ELECTRIC VEHICLE AND METHOD THEREOF}

The present invention relates to an engine start control apparatus and method for a hybrid vehicle, and more particularly, when an engine and a motor are connected through a one-way clutch in a hybrid vehicle, and the hybrid mode is converted to start the engine while driving at a low vehicle speed. The present invention relates to an engine start control apparatus and method for a hybrid vehicle in which the UD clutch of a transmission is released and neutralized, then the engine is started, and the UD clutch is slip-controlled and fastened.

In general, a hybrid electric vehicle (HEV) refers to a vehicle that uses two or more different driving sources, but generally an engine that obtains rotational power by burning fuel (fossil fuel such as gasoline) (Internal Combustion Engine, ICE) It refers to a vehicle that is driven by using a motor that obtains rotational power from and battery power.

In the course of driving with two types of driving sources consisting of an engine and a motor, a hybrid vehicle can output optimal torque depending on how the engine and motor operate in harmony while maximizing vehicle fuel economy.

Hybrid vehicles can use an engine and a motor to form a drivetrain in various structures. A TMED (Transmission Mounted Electric Device) type is known in which the engine and the motor are connected through an engine clutch and a transmission is connected to the output side of the motor.

This TMED hybrid system is capable of charging and discharging the motor through the engine and motor as driving sources for vehicle driving, the engine clutch interposed between the engine and the motor, a transmission connected to the output side of the motor, an inverter to drive the motor, and an inverter. It may include a battery connected to each other.

In addition, a hybrid starter and generator (HSG) that is connected to the engine so as to be able to transmit power to start the engine or to perform power generation using engine power may be included.

The engine clutch is operated to close or open by hydraulic pressure to connect or block the engine and the motor so as to transmit power.

In addition, the inverter converts the DC current of the battery into a three-phase AC current to drive the motor and applies it to the motor.

The transmission transmits the power of the motor or the combined power of the engine and the motor to the drive wheel through a drive shaft, and an automatic transmission (AT) or a double clutch transmission (DCT) may be used.

Such a hybrid vehicle can be driven in an electric vehicle (EV) mode, which is a pure electric vehicle mode using only the power of a motor, or a hybrid electric vehicle (HEV) mode, which uses a combination of engine power and motor power.

In addition, during braking of the vehicle or coasting due to inertia, a regeneration mode is performed in which the kinetic energy of the vehicle is recovered through a motor to charge the battery.

In the regenerative mode, the motor receiving the kinetic energy of the vehicle operates as a generator to charge the battery connected through the inverter.

The background technology of the present invention is disclosed in Korean Patent Publication No. 10-1481335 (announced on Jan. 9, 2015, shift control method of a hybrid vehicle).

In this way, in the hybrid vehicle, an engine clutch is interposed between the engine and the motor to close or open by hydraulic pressure to connect or cut off the engine and the motor so as to transmit power.

Therefore, an operating motor or a hydraulic control mechanism for operating the engine clutch is required, as well as an impact occurs when the engine clutch is engaged and released. Therefore, cooperative control for the ISG motor and engine control to mitigate such impact is required. In addition, there is a problem in that the complexity of the control that must control the engine clutch during EV-HEV mode conversion increases.

The present invention was conceived to improve the above problems, and an object of the present invention according to one aspect is to connect an engine and a motor through a one-way clutch in a hybrid vehicle, and convert the engine to a hybrid mode while driving at a low vehicle speed. It is to provide an engine start control apparatus and method for a hybrid vehicle in which the UD clutch of a transmission is released and neutralized when starting, and then the engine is started and the UD clutch is slip-controlled to engage.

An engine start control apparatus for a hybrid vehicle according to an aspect of the present invention includes a one-way clutch interposed between the engine and the motor; A vehicle state input unit for receiving vehicle state information; An engine driving unit that drives the engine; A UD clutch driving unit controlling the UD clutch of the transmission to regulate the rotational force of the input shaft; And when the engine start condition is satisfied by receiving the vehicle status information from the vehicle status input unit, the engine driving unit is controlled to start the engine, but when the input shaft rotation speed is less than the set rotation speed, the UD clutch driving unit is controlled to neutralize the transmission and the engine It characterized in that it comprises a; control unit for starting.

In the present invention, the set rotation speed is characterized in that the idle rotation speed of the engine.

In the present invention, the engine starting condition is a condition in which the engine is switched to a hybrid drive mode in which the engine is driven in a stopped state while the vehicle is running.

In the present invention, the control unit controls the UD clutch driving unit to release the UD clutch to neutralize the transmission, and then starts the engine, and when the UD clutch is slip-controlled and the engine rotational speed matches the synchronous rotational speed of the input shaft of the transmission, the UD clutch is activated. It is characterized by fastening.

In the present invention, the controller performs slip control through a creep control after starting the engine when controlling the slip of the UD clutch, and performs slip control through launch control when an accelerator pedal is detected.

A method for controlling engine start of a hybrid vehicle according to another aspect of the present invention includes: determining, by a controller, an engine start condition by receiving status information of the vehicle; Comparing the input shaft rotation speed and the set rotation speed of the transmission when the control unit satisfies the engine starting condition; Starting the engine by comparing the input shaft rotation speed with the set rotation speed by the control unit and controlling the engine driving unit when the input shaft rotation speed is greater than or equal to the set rotation speed; And when the input shaft rotation speed is less than the set rotation speed by comparing the input shaft rotation speed with the set rotation speed by the control unit, controlling the UD clutch driving unit to release the UD clutch of the transmission to neutralize the transmission and then start the engine. do.

In the present invention, the determining of the engine starting condition is characterized in that the control unit determines a condition in which the engine is switched to the hybrid drive mode in which the engine is driven from a stop state while the vehicle is running.

In the present invention, the set rotation speed is characterized in that the idle rotation speed of the engine.

In the present invention, the step of driving the engine after neutralizing the transmission may include: a control unit controlling the UD clutch driving unit to release the UD clutch; Starting the engine after the controller releases the UD clutch; Slip-controlling the UD clutch after the control unit starts the engine; And engaging the UD clutch when the control unit slips the UD clutch and the engine rotational speed matches the synchronous rotational speed of the input shaft of the transmission.

In the present invention, the step of controlling the slip of the UD clutch includes controlling the slip through the creep control after the control unit starts the engine and performing the slip control through launch control when the accelerator pedal is detected. do.

An engine start control apparatus for a hybrid vehicle and a method thereof according to an aspect of the present invention are UD of a transmission when an engine and a motor are connected through a one-way clutch in a hybrid vehicle, and converted to a hybrid mode while driving at a low vehicle speed to start the engine. By releasing and neutralizing the clutch, starting the engine and controlling the slip control of the UD clutch, a separate configuration for driving by applying the engine clutch is not required, and the engine power can be transmitted or cut off by the mechanical feature of the one-way clutch. By reducing the number of separate operating mechanisms, cost reduction, weight reduction, and number of parts can be reduced.

1 is a schematic diagram of a drive system of a hybrid vehicle according to an embodiment of the present invention.
2 is a block diagram showing an engine start control apparatus for a hybrid vehicle according to an embodiment of the present invention.
3 is a graph for explaining a driving process of a UD clutch by an engine start control device of a hybrid vehicle according to an embodiment of the present invention.
4 is a flowchart illustrating a method for controlling engine start of a hybrid vehicle according to an embodiment of the present invention.

Hereinafter, an apparatus and method for controlling engine start of a hybrid vehicle according to the present invention will be described with reference to the accompanying drawings. In this process, the thickness of the lines or the size 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 and 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.

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

As shown in FIG. 1, the hybrid vehicle according to an embodiment of the present invention is a TMED (Transmission Mounted Electric Device) type, and the engine 20, the motor 40, and the engine 20 serving as driving sources for vehicle driving. The motor 40 through the one-way clutch 30 interposed between the motor 40, the transmission 50 connected to the output side of the motor 40, the inverter 70 for driving the motor 40, and the inverter 70 ) May include a battery 80 connected to be charged and discharged.

In addition, a hybrid starter and generator (HSG) 10 may be included that is connected to the engine 20 so as to be capable of transmitting power to start the engine 20 or perform power generation using the power of the engine 20.

In addition, the inverter 70 converts the DC current of the battery 80 into a three-phase AC current to drive the motor 40 and applies it to the motor 40.

The transmission 50 shifts the power of the motor 40 or the combined power of the engine 20 and the motor 40 and transmits it to the drive wheel 60 through a drive shaft, and an automatic transmission (AT) or DCT ( Double Clutch Transmission) can be used.

Such a hybrid vehicle is an electric vehicle (EV) mode, which is a pure electric vehicle mode using only the power of the motor 40, or a hybrid electric vehicle (HEV) mode that combines the power of the engine 20 and the motor 40. You can run.

In addition, when the vehicle is braking or coasting due to inertia, a regeneration mode is performed in which the kinetic energy of the vehicle is recovered through the motor 40 and the battery 80 is charged.

At this time, the one-way clutch 30 interposed between the engine 20 and the motor 40 may mechanically cut off the power of the engine 20 in the EV mode or the regenerative braking mode.

2 is a block diagram showing an engine start control apparatus of a hybrid vehicle according to an embodiment of the present invention, and FIG. 3 is a driving process of a UD clutch by the engine start control apparatus of a hybrid vehicle according to an embodiment of the present invention. This is a graph to explain

As shown in FIG. 2, the engine start control device of a hybrid vehicle according to an embodiment of the present invention is a start control device in a hybrid vehicle in which a one-way clutch 30 is interposed between the engine 20 and the motor 40. As such, it may include a vehicle state input unit 100, an engine driving unit 400, a UD clutch driving unit 300, and a control unit 200.

The vehicle status input unit 100 receives various status information of the vehicle.

For example, status information such as an operating state of the engine 200, a driving mode of the vehicle, an engine speed, an input shaft rotation speed of the transmission 50, and an operation state of an accelerator pedal may be input.

The engine driving unit 400 may drive the engine 20 by injecting and igniting fuel into the engine 20 while starting the engine 20 by operating the starter generator 10.

The UD clutch driving unit 300 releases the UD clutch 55 of the transmission 50 to block the rotational force of the input shaft 52 of the transmission 50 to neutralize the transmission 50, and the UD clutch 55 through slip control. By fastening the rotational force of the engine 20 or the motor 40 can be transmitted to the transmission 50.

The controller 200 starts the engine 20 by controlling the engine driving unit 400 when the engine starting condition is satisfied by receiving the vehicle state information from the vehicle state input unit 100, but the input shaft of the transmission 50 is rotated. If the number is less than the set number of revolutions, the engine 20 may be started after neutralizing the transmission 50 by controlling the UD clutch driving unit 300.

Here, the engine starting condition is a condition in which the engine 20 is switched to a hybrid drive mode in which the engine 20 is driven from a stop state while the vehicle is running, and the set rotation speed is the idle rotation speed of the engine 20, and the controller ( In 200), when the engine starting condition is satisfied below the set rotational speed, the UD clutch 55 of the transmission 50 is released to neutralize the transmission 50 to start the engine 20 and then the engine 20 is started. .

That is, the control unit 200 controls the UD clutch driving unit 300 to release the UD clutch 55 to neutralize the transmission 50, then starts the engine 20, and controls the UD clutch 55 to slip. When the rotational speed matches the synchronous rotational speed of the input shaft of the transmission 50, the UD clutch 55 may be engaged to transmit power.

Here, the controller 200 neutralizes the UD clutch 55 when controlling the slip, and then performs slip control through the launch control when the accelerator pedal is sensed while controlling the slip through creep control. .

As shown in FIG. 3, when looking at the changes in the number of revolutions of the input shaft and the number of engines, the controller 200 determines the UD clutch 55 of the transmission 50 to start the engine 20 when the engine starting condition is less than the set number of revolutions. ) To neutralize the transmission 50, and then start the engine 20.

At this time, the control unit 200 controls the launch control when the engine speed increases by sensing the accelerator pedal while maintaining the engine speed constant while controlling the slip through the creep control after starting the engine 20. Through this, sleep control can be performed.

Thereafter, when the engine rotational speed matches the synchronous rotational speed of the input shaft of the transmission 50, the control unit 200 engages the UD clutch 55 and transmits the power of the engine 20 to the transmission 50.

As described above, according to the engine start control apparatus of a hybrid vehicle according to an embodiment of the present invention, the engine and the motor are connected through a one-way clutch in the hybrid vehicle, and the hybrid mode is converted to start the engine while driving at a low vehicle speed. When the UD clutch of the transmission is released and neutralized, the engine is started and the UD clutch is slip-controlled and fastened, so that a separate configuration for driving by applying the engine clutch is not required, and the engine power is transmitted by the mechanical feature of the one-way clutch. Because it can be cut off or cut off, it is possible to reduce separate operating mechanisms, thereby reducing cost, weight and number of parts.

4 is a flowchart illustrating a method for controlling engine start of a hybrid vehicle according to an embodiment of the present invention.

As shown in Figure 4, in the engine start control method of a hybrid vehicle according to an embodiment of the present invention, a one-way clutch 30 is interposed between the engine 20 and the motor 40 TMED (Transmission Mounted Electric Device) type The starting control method based on the hybrid vehicle will be described.

First, the control unit 200 receives vehicle status information from the vehicle status input unit 100 (S10).

After receiving the status information of the vehicle in step S10, the control unit 200 determines the engine starting condition (S20).

Here, the engine starting condition may mean a condition in which the engine 20 is switched to a hybrid driving mode in which the engine 20 is driven while the engine 20 is stopped while the vehicle is running.

When the engine starting condition is determined in step S20 and the engine starting condition is satisfied, the controller 200 compares the input shaft rotation speed of the transmission 50 and the set rotation speed (S30).

Here, the set rotation speed may be set as the idle rotation speed of the engine 20.

When the input shaft rotation speed is compared with the set rotation speed in step S30 and the input shaft rotation speed is greater than or equal to the set rotation speed, the control unit 200 controls the engine driving unit 400 to start the engine 20 to increase the power of the engine 20. It is transmitted to the transmission 50 to operate in the HEV mode (S40).

On the other hand, if the input shaft rotation speed is less than the set rotation speed as a result of comparing the input shaft rotation speed and the set rotation speed in step S30, the controller 200 controls the UD clutch driving unit 300 to activate the UD clutch 55 of the transmission 50. It is released to neutralize the transmission 50 (S50).

After releasing the UD clutch 55 in step S50, the control unit 200 controls the engine driving unit 400 to start the engine 20 (S60).

After starting the engine 20 in step S60, the control unit 200 controls the slip control of the UD clutch 55 (S70).

Here, when the UD clutch 55 is slip-controlled, the controller 200 starts the engine 20 and then controls the slip through creep control, and when an accelerator pedal is detected, the slip control is performed through launch control. You can do it.

That is, after starting the engine 20, the control unit 200 controls the launch through the creep control and controls the launch control when the engine speed is increased by detecting the accelerator pedal while maintaining the engine speed constant. Sleep control can be performed through

While controlling the slip of the UD clutch 55 in step S70, the controller 200 determines whether the engine speed and the synchronous speed of the input shaft of the transmission 50 match (S80).

After determining whether the engine speed and the input shaft synchronous speed are identical in step S80, if the engine speed matches the input shaft synchronous speed, the control unit 200 engages the UD clutch 55 to transfer the power of the engine 20 to the transmission 50. To be driven in HEV mode (S90).

As described above, according to the engine start control method of a hybrid vehicle according to an embodiment of the present invention, the engine and the motor are connected through a one-way clutch in the hybrid vehicle, and the hybrid mode is converted to start the engine while driving at a low vehicle speed. When the UD clutch of the transmission is released and neutralized, the engine is started and the UD clutch is slip-controlled and fastened, so that a separate configuration for driving by applying the engine clutch is not required and the engine power is transmitted by the mechanical feature of the one-way clutch. Because it can be cut off or cut off, it is possible to reduce separate operating mechanisms, thereby reducing cost, weight and number of parts.

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, a microprocessor, an integrated circuit or a 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.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is only illustrative, and those of ordinary skill in the field to which the 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: start generator 20: engine
30: one-way clutch 40: motor
50: transmission 52: input shaft
55: UD clutch 60: drive wheel
70: inverter 80: battery

Claims (10)

A one-way clutch interposed between the engine and the motor;
A vehicle state input unit for receiving vehicle state information;
An engine driving unit driving the engine;
A UD clutch driving unit controlling the UD clutch of the transmission to regulate the rotational force of the input shaft; And
When the vehicle status information is received from the vehicle status input unit and the engine starting condition is satisfied, the engine driving unit is controlled to start the engine, but when the input shaft rotation speed is less than the set rotation speed, the UD clutch driving unit is controlled to control the transmission. And a control unit for starting the engine after neutralizing the engine.
The engine start control apparatus for a hybrid vehicle according to claim 1, wherein the set rotation speed is an idle rotation speed of the engine.
The apparatus of claim 1, wherein the engine starting condition is a condition in which the engine is switched to a hybrid drive mode in which the engine is driven from a stop state while the vehicle is running.
The method of claim 1, wherein the control unit controls the UD clutch driving unit to release the UD clutch to neutralize the transmission, and then start the engine, and while controlling the UD clutch to slip, the engine speed is synchronized with the input shaft of the transmission. The engine start control apparatus of a hybrid vehicle, characterized in that the UD clutch is engaged when the rotational speed is identical.
The method of claim 4, wherein the control unit performs slip control through launch control when an accelerator pedal is detected while controlling slip through creep control after starting the engine when controlling the slip of the UD clutch. Engine start control device of a hybrid vehicle, characterized in that.
Determining, by the controller, an engine starting condition by receiving state information of the vehicle;
Comparing an input shaft rotation speed of a transmission with a set rotation speed when the control unit satisfies the engine starting condition;
Starting the engine by comparing the input shaft rotation speed with the set rotation speed by the control unit and controlling an engine driving unit when the input shaft rotation speed is greater than or equal to the set rotation speed; And
The control unit compares the input shaft rotation speed with the set rotation speed, and when the input shaft rotation speed is less than the set rotation speed, controls the UD clutch driving unit to release the UD clutch of the transmission to neutralize the transmission, and then start the engine. Engine start control method of a hybrid vehicle comprising a.
The hybrid according to claim 6, wherein the determining of the engine starting condition comprises determining, by the control unit, a condition for switching to a hybrid drive mode in which the engine is driven from a stop state of the engine while the vehicle is running. Vehicle engine start control method.
The method for controlling engine start of a hybrid vehicle according to claim 6, wherein the set rotational speed is an idle rotational speed of the engine.
The method of claim 6, wherein the step of driving the engine after neutralizing the transmission comprises:
Releasing the UD clutch by controlling the UD clutch driving unit by the control unit;
Starting the engine after the control unit releases the UD clutch;
Slip-controlling the UD clutch after the control unit starts the engine; And
And engaging the UD clutch when the control unit slips the UD clutch and the engine rotational speed coincides with the synchronous rotational speed of the input shaft of the transmission.
The slip control according to claim 9, wherein the slip control of the UD clutch comprises slip control through a creep control after the control unit starts the engine, and when an accelerator pedal is detected, slip control through launch control. Engine start control method of a hybrid vehicle, characterized in that performing.

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