KR100906870B1 - Method for controlling hybrid electric vehicle provided with adaptive cruise control system - Google Patents

Abstract

The present invention relates to a control method of a hybrid vehicle equipped with an adaptive cruise control system, wherein the adaptive cruise control (ACC) system performs a constant speed or inter-vehicle distance control by measuring a vehicle distance, a preceding vehicle speed, and a host vehicle speed. If the ACC controller detects the stop of the preceding vehicle while the ACC controller detects the stop of the preceding vehicle, if it is determined that the stopping of the vehicle is necessary, the vehicle is stopped by stopping the fuel injection of the engine in advance by cooperatively controlling the HCU and ECU. The present invention relates to a control method of a hybrid vehicle equipped with an adaptive cruise control system capable of preventing unnecessary fuel consumption until an idle stop entry point, thereby improving vehicle fuel efficiency.

Hybrid vehicle, cruise control, distance control, adaptive, idle stop, fuel injection cutoff, fuel cut, regenerative braking, fuel economy

Description

Method for controlling hybrid electric vehicle provided with adaptive cruise control system

The present invention relates to a control method of a hybrid vehicle, and more particularly, to a control method of a hybrid vehicle equipped with an adaptive cruise control (ACC) system.

In general, a hybrid vehicle in a broad sense means to drive a vehicle by efficiently combining two or more different power sources, but in most cases, an engine (internal combustion engine) that obtains rotational force by burning fuel (fossil fuel such as gasoline). It means a vehicle driven by an electric motor that obtains rotational power by the power of the battery, and this is called a hybrid electric vehicle (HEV).

In response to the recent demand for improving fuel economy and developing more environmentally friendly products, research on hybrid electric vehicles is being actively conducted.

In a hybrid vehicle, the selection and switching of the electric vehicle (EV) mode that drives the vehicle using only the rotational force of the electric motor, the engine mode using only the rotational force of the engine, and the hybrid electric vehicle (HEV) mode that simultaneously uses the rotational force of the engine and the electric motor are possible. It is possible.

In addition, in a hybrid vehicle, the engine is started by an efficient electric motor (starting the engine after the initial start and idle stop) and the initial start is performed, and the fuel economy is improved by the idle stop function which turns off the engine when the vehicle is stopped. And exhaust gas reduction.

As described above, the hybrid vehicle has the advantage of using the engine's mechanical energy and the electric energy of the battery together, and can use energy efficiently. At the same time, since the energy is recovered by the electric motor, there is an advantage that the efficient energy can be used.

Meanwhile, adaptive cruise control (ACC) systems are being widely applied as one of vehicle convenience devices.

The adaptive cruise control system performs appropriate acceleration and deceleration by automatically controlling the throttle valve, brake, and transmission of the vehicle according to the driving environment of the vehicle, that is, the position and distance of the preceding vehicle detected by the radar mounted in front of the vehicle. This is to maintain a proper distance from the preceding vehicle.

The adaptive cruise control system performs the constant speed control when there is no preceding vehicle, and controls the distance between the vehicle and the vehicle so as not to be closer to the preceding vehicle by a predetermined distance.

Here, the inter-vehicle distance control refers to automatically adjusting the driving and braking device to maintain the safety distance by measuring the distance to the preceding vehicle.

That is, when the distance to the preceding vehicle is reduced to within the set safety distance, the braking device is used to reduce the speed of the vehicle so as to increase the distance to the preceding vehicle to secure the safety distance.

Typically, the adaptive cruise control system consists of a vehicle distance sensor such as a radar sensor or an ultrasonic sensor, a vehicle control device such as an engine and an ESP, and a controller for control calculation.

1 is a view showing main components in an example of an adaptive cruise control system, and FIGS. 2 and 3 are views showing an operation example of the adaptive cruise control system.

In the example of FIG. 1, the main components include the brake controller 11, the brake actuator 12, the throttle actuator 13, the radar sensor 14, the engine controller 15, and the wheel speed sensor 16. .

The adaptive cruise control system may be applied to a hybrid vehicle as well as a general vehicle. FIG. 4 is a schematic diagram of a hybrid vehicle equipped with an adaptive cruise control system.

As shown, the hybrid vehicle is equipped with a hybrid control unit (HCU) 130 that controls the overall vehicle, and is provided with a controller for each device constituting the system.

For example, a hybrid vehicle basically includes an engine control unit (ECU) 140 that controls the overall operation of the engine, a brake controller 150 that controls the brake operation, and a transmission controller that controls the transmission. The control unit (TCU) 160, a motor controller (Motor Control Unit (MCU) 170) for controlling the overall operation of the motor is provided.

In addition, as a component of the adaptive cruise control system, a radar sensor, a signal processor 110 and an ACC (Active Cruise Control) controller 120, which are inter-vehicle distance sensors, are mounted.

Here, the HCU 130 is a top controller of each controller, and each controller is connected to a high-speed CAN communication line around the HCU, which is the top controller, so that the upper controller sends commands to the lower controller while exchanging information between the controllers. It is.

Of course, each of these controllers may in fact be a separate unit but a functional software module.

In the adaptive cruise control (ACC) system as described above, the radar sensor and the signal processor 110 transmit the distance to the preceding vehicle and the relative speed with the preceding vehicle to the ACC controller 120, and the ACC controller 120 The HCU 130 transmits the required acceleration and the stop request, etc., and the HCU 130 transmits the required brake amount to the brake controller 150 so that brake control is performed.

In addition, the HCU 130 transmits the required torque to the ECU 140 to control the engine, and transmits the required transmission ratio to the TCU 160 to perform the shift control, and through the motor through the MCU 170. Engine start and regenerative braking control are performed.

In a typical hybrid vehicle, as shown in FIG. 5, the HCU 130 implements an idle stop function by stopping fuel injection of the engine when the vehicle stops, thereby preventing unnecessary consumption of fuel in an idle stop section in which the engine is turned off. It is possible to improve fuel economy and reduce exhaust gas.

When the ACC control is being performed, the vehicle follows the preceding vehicle while maintaining a constant interval. In general, the ACC controller 120 transfers control to the driver without performing ACC control when the speed of the own vehicle is very low.

However, in the case of the ACC controller including the stop / start function, when the preceding vehicle stops, the host vehicle stops, and when the preceding vehicle starts, the host vehicle also starts together.

In this case, in the case of the hybrid vehicle, the engine is stopped when the vehicle stops for a while as described above to reduce fuel consumption.

However, in the existing hybrid vehicle, the fuel injection is blocked while the vehicle is stopped. The disadvantage of the conventional control method in the hybrid vehicle having the adaptive cruise control (ACC) system is that the stopping of the own vehicle is expected in advance when the preceding vehicle is stopped. Despite the fact that the vehicle can be stopped, the fuel is cut off and the idle stop is entered after the vehicle actually stops.

Therefore, as shown in FIG. 6, when the preceding vehicle decelerates and stops, the host vehicle decelerates according to the preceding vehicle deceleration, and enters the fuel cutoff and idle stop in the state where the host vehicle is completely stopped. Will consume additional fuel until it stops and enters the idle stop.

In addition, there is an unnecessary brake operation before entering the idle stop of the own vehicle. When decelerating the vehicle through the brake, there is an unreasonable use of unnecessary energy to operate the brake while producing unnecessary energy from the engine.

Therefore, the present invention has been invented to solve the above problems, and when the ACC controller detects the stop of the preceding vehicle, it is determined whether the stop of the own vehicle is necessary, and when it is determined that the stop of the own vehicle is necessary, the HCU and the ECU By cooperatively controlling the fuel injection of the engine in advance, it is possible to prevent unnecessary fuel consumption until the vehicle stops and enter the idle stop, thereby controlling hybrid vehicles equipped with an adaptive cruise control system that can improve vehicle fuel economy. The purpose is to provide a method.

In addition, the vehicle is decelerated by regenerative braking when the vehicle stops, thereby reducing unnecessary brake operation before entering the idle stop, thereby providing a control method of a hybrid vehicle which reduces energy use according to the brake operation.

In order to achieve the above object, the present invention, in the control method of a hybrid vehicle equipped with an adaptive cruise control (ACC) system, when the ACC controller detects the stop of the preceding vehicle during the inter-vehicle distance control, the stop of the own vehicle is Determining whether it is necessary; Requesting entry of an idle stop when it is determined that stopping of the own vehicle is required; And the hybrid controller requests an immediate fuel injection stop of the engine by the idle stop entry request of the ACC controller, so that the fuel injection of the engine is stopped before the vehicle speed of the own vehicle reaches a stop state.

Here, the hybrid controller performs the vehicle deceleration through regenerative braking during the deceleration of the preceding vehicle during the inter-vehicle distance control and if the vehicle is stopped after the regenerative braking, the brake control for maintaining the stop state is performed. .

In addition, the present invention, if the ACC controller detects the start of the preceding vehicle, making an idle stop release request; Causing the hybrid controller to immediately perform fuel injection by the idle stop release request of the ACC controller so that the fuel pre-injection is performed before the vehicle starts according to the preceding vehicle start, and then restarting the engine to release the idle stop. It features.

According to the control method of the present invention as described above, when the ACC controller detects the stopping of the preceding vehicle, it is determined whether the stopping of the own vehicle is required, and when it is determined that the stopping of the own vehicle is necessary, cooperative control with the HCU and the ECU is performed to control the fuel of the engine. By stopping the injection in advance, it is possible to prevent unnecessary fuel consumption until the vehicle stops to enter the idle stop, thereby improving vehicle fuel economy.

In addition, the vehicle is decelerated by regenerative braking when the vehicle is stopped, thereby reducing unnecessary brake operation before entering the idle stop, thereby reducing energy usage.

In addition, when the ACC controller detects the start of the preceding vehicle, the engine is started by injecting fuel in advance before the departure of the own vehicle, thereby preventing the start-up delay after the idle stop is released.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method of a hybrid vehicle, wherein a fuel injection is performed in advance when a preceding vehicle stops in a hybrid vehicle equipped with an adaptive cruise control (hereinafter referred to as an ACC) system and a stop of the own vehicle is predicted. Its main feature is to cut off fuel consumption.

That is, when the ACC controller detects the stop of the preceding vehicle while the ACC system performs the constant speed driving or the distance control by measuring the distance, the preceding vehicle speed, and the own vehicle speed in the hybrid vehicle, it is determined whether the vehicle is required to stop. If it is determined that the stopping of the vehicle is necessary, cooperative control with the hybrid controller (vehicle controller, hereinafter referred to as HCU) and the engine controller (hereinafter referred to as ECU) is to stop the fuel injection of the engine in advance. Fuel cut mode in advance when expected).

FIG. 7 is a timing chart illustrating fuel injection blocking, idle stop entry and release, and fuel pre-injection in the control method of the hybrid vehicle according to the present invention, and FIG. 8 illustrates the idle stop entry method of the hybrid vehicle according to the present invention. 9 is a flowchart illustrating a method of releasing an idle stop of a hybrid vehicle according to the present invention.

First, as shown in FIG. 7, the ACC system measures the inter-vehicle distance, the preceding vehicle speed, the host vehicle speed, and the like to perform normal constant speed driving or inter-vehicle distance control.

In particular, during the inter-vehicle distance control, the ACC system measures the position (vehicle distance) and speed of the preceding vehicle by using the inter-vehicle sensor (eg radar sensor), and then controls the host vehicle to maintain the target inter-vehicle distance through the ACC controller. do.

During the inter-vehicle distance control, if the ACC controller detects the stop after deceleration of the preceding vehicle, it is determined whether the stop of the vehicle is required. At this time, if it is determined that the stop of the vehicle is required, the ICU requests to enter the idle stop.

The HCU receives the idle stop entry request from the ACC controller and immediately makes a fuel cut request to the ECU. Accordingly, the ECU performs a fuel cut to block the fuel injection, thereby preventing additional fuel injection into the engine.

This fuel injection blockage is performed before the stopping state of the vehicle. When the stopping of the vehicle is expected by the cooperative control of the ACC controller, the HUC, and the ECU, the HCU receives an idle stop entry request from the ACC controller and the fuel is supplied to the ECU. The cut request is made, and the ECU performs a fuel cut so that the fuel injection is stopped before the vehicle speed reaches the stop state (the vehicle stop state).

As described above, in the present invention, when the stopping of the host vehicle is expected during the inter-vehicle distance control, by stopping the fuel injection in advance before the stopping of the host vehicle, unnecessary fuel consumption as in the related art can be reduced, and fuel efficiency can be improved by saving fuel.

In the present invention, when the host vehicle deceleration is required according to the preceding vehicle deceleration, the ACC controller, the HCU, and the MCU cooperatively control the braking using the regenerative braking function of the driving motor or the generator.

That is, when the preceding vehicle is decelerated during the inter-vehicle distance control of the ACC system, the ACC controller recognizes this through the radar sensor and requests a regenerative braking request to the HUC controller. Therefore, the HCU decelerates and stops the vehicle through the regenerative braking control. .

In addition, when the HCU stops by regenerative braking, the brake control is performed to maintain the stopping state through the brake controller.

In this manner, in the present invention, unnecessary brake operation can be reduced by using the regenerative braking function.

In addition, in the control method of the present invention, when the preceding vehicle starts using the radar sensor, when the departure of the own vehicle is expected, the idle stop release speed may be increased by preparing for the departure in advance.

That is, when the ACC controller detects the start of the preceding vehicle through the inter-vehicle sensor, that is, the radar sensor, the idle stop release request is made to the HCU.

The HCU receives the idle stop release request from the ACC controller and immediately requests fuel pre-injection from the ECU. Accordingly, the ECU releases the fuel cut to perform the fuel pre-injection.

Thereafter, the ACC controller determines whether the departure of the own vehicle is necessary, and if it is determined that the departure of the own vehicle is required, the ACC controller starts the vehicle and continues to perform the ACC control.

Such fuel pre-injection is performed by the ACC controller immediately requesting the release of the idle stop before the idle stop is actually released and before the departure of the own vehicle, and before the start of the motor drive and the brake release time for starting the engine. The engine fuel is re-injected in advance.

In the conventional hybrid vehicle, since a series of operations such as re-injecting fuel to the engine, driving the motor, and releasing the brake have to be performed, there is a delay in the start time after the idle stop is released. Since there is no oscillation delay.

8 and 9 are flowcharts illustrating the control method of the present invention as described above. Referring to this, first, the ACC system uses the inter-vehicle distance sensor (eg, radar sensor) in a state where a target inter-vehicle distance and speed are set and input. The ACC control is performed by measuring the distance to the preceding vehicle and the speed of the preceding vehicle, and measuring the own vehicle speed (detected by the wheel speed sensor).

At this time, the ACC controller calculates the required acceleration for maintaining the inter-vehicle distance, calculates the required acceleration for maintaining the constant speed, and performs the inter-vehicle distance control and the constant speed travel control.

If the ACC controller detects the stop after deceleration of the preceding vehicle during such ACC control, it is determined whether the stop of the vehicle is necessary, and if it is determined that the stop of the vehicle is not necessary, the inter-vehicle distance control or the constant speed driving control is performed. When it is determined that the stop is necessary, the idle stop entry request signal is transmitted to the HCU.

Accordingly, while the HCU is performing hybrid control according to the accelerator pedal and driving state, the ACU controller receives an idle stop entry request signal from the ACC controller and processes the fuel injection. The HCU immediately stops fuel injection by the idle stop entry request signal from the ACC controller. After that, the vehicle is decelerated by regenerative braking.

In addition, the HCU performs brake control to maintain a stopped state when the vehicle is stopped.

Meanwhile, referring to FIG. 9, when the idle stop is released, when the ACC system detects the start of the preceding vehicle while the idle stop and the stop state are maintained, the ACC controller transmits an idle stop release request signal to the HCU. .

Accordingly, the HCU starts fuel injection (fuel pre-injection) in response to the idle stop release request signal of the ACC controller in the state of performing brake control for maintaining the stop state, and starts the engine through the motor.

Thereafter, the ACC controller determines whether the departure of the vehicle is necessary, and if it is determined that the departure of the vehicle is required, the ACC controller starts the vehicle and performs the ACC control. At this time, the HCU requests the brake release to start the vehicle and the brake controller releases the brake. Release it.

As described above, according to the control method of the hybrid vehicle according to the present invention, the ACC controller measures the inter-vehicle distance, the preceding vehicle speed, the host vehicle speed, and the like to control the constant speed or the inter-vehicle distance while the ACC controller stops the preceding vehicle. In case of detection, it is determined whether the stop of the vehicle is necessary, and if it is determined that the stop of the vehicle is necessary, cooperative control with the HCU and ECU stops the fuel injection of the engine in advance. It is possible to prevent, thereby improving the vehicle fuel economy.

1 shows the main components in one example of an adaptive cruise control system,

2 and 3 show an example of the operation of the adaptive cruise control system,

4 is a schematic diagram of a hybrid vehicle equipped with an adaptive cruise control system;

5 is a timing chart showing an idle stop, fuel injection blocking, and brake operation in a typical hybrid vehicle;

6 is a view for explaining the problems of the prior art,

7 is a timing chart showing fuel injection blocking, idle stop entry and release, and fuel pre-injection in a control method of a hybrid vehicle according to the present invention;

8 is a flowchart illustrating a method of entering an idle stop of a hybrid vehicle according to the present invention;

9 is a flowchart illustrating a method of releasing an idle stop of a hybrid vehicle according to the present invention.

<Explanation of symbols for the main parts of the drawings>

110: radar sensor and signal processor 120: ACC controller

130: hybrid controller 140: engine controller

150: brake controller 160: transmission controller

170: motor controller

Claims (3)

In the control method of a hybrid vehicle equipped with an adaptive cruise control (ACC) system, When the ACC controller detects a stop of the preceding vehicle while performing the inter-vehicle distance control, determining whether the stop of the own vehicle is required; Requesting entry of an idle stop when it is determined that stopping of the own vehicle is required; The hybrid controller requesting an immediate stop of fuel injection of the engine by the idle stop entry request of the ACC controller so that the fuel injection of the engine is stopped before the vehicle speed of the own vehicle reaches a stopped state; Method of controlling a hybrid vehicle equipped with an adaptive cruise control system comprising a. The method according to claim 1, Adaptive control characterized in that the hybrid controller performs the vehicle deceleration by regenerative braking during the deceleration of the preceding vehicle during the inter-vehicle distance control and when the vehicle is stopped after the regenerative braking, the brake control is performed to maintain the stop state. Control method of a hybrid vehicle equipped with a cruise control system. The method according to claim 1, When the ACC controller detects a preceding vehicle start, making an idle stop release request; Enabling the hybrid controller to immediately perform fuel injection by the idle stop release request of the ACC controller so that the fuel pre-injection is performed before the departure of the own vehicle according to the preceding vehicle start, and restarting the engine to release the idle stop; A control method of a hybrid vehicle equipped with an adaptive cruise control system, characterized in that it further comprises.

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