KR102214577B1 - Control method and device of Continuous Variable Valve Duration System - Google Patents

Abstract

Disclosed are a control method and an apparatus of a continuous variable valve system. According to the present invention, the control method of the continuous variable valve system comprises: a step of determining whether an engine rpm count and a measurement value of an intake air volume are effective or not; a step of, if the engine rpm count and the measurement value of the intake air volume are effective, determining whether the current driving area of the engine is a fuel efficiency driving area using a long duration or not; a step of, if it is the fuel efficiency driving area, entering a protective mode for protecting the CVVD motor controller from an overcurrent or not based on the current volume measured in the CVVD motor controller or not; a step of determining whether a drive mode set by the driver is an eco mode or not; and a step of, when entering the protective mode, operating a low pass filter when controlling a target duration, and filtering a CVVD motor control current of a certain value or higher. In the step of filtering a control current, the filtering strength of the low pass filter is controlled to be different according to whether the eco mode determined in the previous step is set or not. The present invention is able to prevent the CVVD motor from being damaged.

Description

Control method and device of Continuous Variable Valve Duration System

The present invention relates to a control method and an apparatus for a continuous variable valve system, and in detail, when a specific condition is met during long duration control that makes the valve opening time relatively long, a low pass filter is operated to reduce unnecessary duration control amount. As a result, the present invention relates to a method and apparatus for controlling a continuous variable valve system to reduce current consumption of the motor controller and protect the CVVD motor controller from overcurrent.

In general, in an internal combustion engine, the opening and closing of the intake valve and the exhaust valve are controlled by a camshaft. The camshaft is connected with a crankshaft (or a chain) that converts the linear motion of the piston in the engine cylinder into rotational motion, and air is sucked into the combustion chamber while the intake valve is opened by the camshaft, and the exhaust valve is While open, combustion gases are released.

CVVD (Continuous Variable Valve Duration) and CVVT (Continuous Variable Valve Timing) are technologies that control the opening and closing time of the valve, respectively. CVVD and CVVT are technologies designed to exhibit optimal engine performance by varying the valve opening time and opening/closing time according to the target value determined from the dedicated map according to the driving conditions such as engine rotation speed or load.

Among them, CVVD is a technology that improves the overall performance of the engine by freely adjusting the opening time of the intake valve, that is, the duration of the valve opening. In other words, CVVD is a technology that changes the time the valve is open according to the operating state of the engine, and uses the difference in speed at which the cam presses the valve when the center of rotation of the camshaft is moved to control the time the valve is open. Have.

The optimal duration control method for continuous variable valve control through the CVVD system is defined as the result of mapping each engine speed and air volume through an engine dyno test. However, this is basically a value optimized in an engine dyno environment with stable air volume and engine speed, and shows a different aspect when the vehicle is actually operated.

In a vehicle, the heavy-duty area corresponds to a frequency area mainly driven by general drivers. Therefore, in general, the compression ratio is lowered by delaying the Intake Valve Close time by maximizing the long duration so that the fuel economy effect can be maximized in the heavy load area.

In a real vehicle, the required air volume is calculated by the engine controller to achieve the required torque required by the driver by operating the accelerator pedal.In general, the required air volume is delayed by the electronic throttle control (ETC) and the structure of the combustion chamber. Since time has to be considered, the request is made by slightly increasing (target required air volume + α) compared to the target value (target required air volume).

In this way, the duration target value in the CVVD system is determined by the target air volume and engine speed. However, depending on the mapping characteristics of the duration map when operating in a heavy-duty area, some areas show a control characteristic of controlling in the long duration direction and then returning to the short duration direction. For this reason, there is a concern of CVVD motor failure due to overcurrent by passing excessive current to the motor controller.

That is, conventionally, there is a problem that the amount of current used is rapidly increased unnecessarily even though the target duration is in the short direction due to an increase in the motor control duty in the section that must pass through the long duration region according to the mapping characteristic. Accumulation can adversely affect the CVVD motor and variable mechanism.

For reference, the long duration direction is a direction in which the valve opening time is relatively long, and the short duration direction is a direction in which the valve opening time is relatively shortened.

Korean Patent Publication No. 2018-0067351 (Publication date 2018. 06. 20)

The technical problem to be solved by the present invention is to reduce the amount of unnecessary duration control by activating a low pass filter during long duration control when certain conditions are met, thereby reducing the current consumption of the motor controller and reducing the current consumption of the motor controller according to the application of overcurrent. It is an object to provide a method and apparatus for controlling a continuous variable valve system capable of suppressing damage.

According to an aspect of the present invention as a means of solving the problem,

Determining whether the measured values of the engine speed and the intake air amount are valid;

Determining whether the current driving region of the engine is a fuel economy driving region using a long duration if the measured values of the engine speed and the intake air amount are valid;

Determining whether to enter a protection mode for protecting the CVVD motor controller from overcurrent based on the amount of current measured inside the CVVD motor controller in the fuel economy operation area; And

Provides a method for controlling a continuous variable valve system comprising: when entering the protection mode, filtering a CVVD motor control current of a predetermined value or more by operating a low pass filter during target duration control.

The control method of the continuously variable valve system according to an aspect of the present invention is preferably,

Determining whether the measured values of the engine speed and the intake air amount are valid;

Determining whether the current driving region of the engine is a fuel economy driving region using a long duration if the measured values of the engine speed and the intake air amount are valid;

Determining whether to enter a protection mode for protecting the CVVD motor controller from overcurrent based on the amount of current measured inside the CVVD motor controller in the fuel economy operation area;

Determining whether the drive mode set by the driver is an eco mode; And

In the case of entering the protection mode, filtering a CVVD motor control current of a predetermined value or more by operating a low pass filter when controlling a target duration;

In the filtering of the control current, the filtering strength of the low pass filter may be differently adjusted according to whether or not the fuel economy mode determined in the previous step is set.

Here, in the step of determining whether the measured values of the engine speed and intake air amount are valid, if there is no error signal output from the crank angle sensor and the air amount measuring sensor, it may be determined that the measured values of the engine speed and the intake air amount are valid.

In addition, when the drive mode is set to the fuel economy mode (Eco Mode), the filtering strength of the low pass filter can be adjusted relatively high.

In contrast, when the drive mode is not the fuel economy mode (Eco Mode), the filtering strength of the low pass filter can be adjusted to be relatively low.

In addition, in the step of determining whether to enter the protection mode, monitoring whether the amount of current measured inside the CVVD motor controller exceeds a preset threshold current amount, and if the measured current amount exceeds a preset threshold current amount, During counting, the counted time is accumulated, and when the accumulated time reaches a set threshold, it is judged as a dangerous situation, and it can be decided to enter the protection mode.

According to another aspect of the present invention as a means of solving the problem,

Engine controller; And

Includes; a CVVD motor controller connected to exchange information with each other through CAN communication with the engine controller,

The engine controller,

Determines whether to enter the protection mode that protects the CVVD motor controller from overcurrent based on the amount of current measured inside the CVVD motor controller,

When entering the protection mode, when controlling the valve duration through the CVVD motor controller, a low pass filter is operated to filter the CVVD motor control current of a predetermined value or more.

Preferably, the engine controller may determine whether to enter the protection mode after when the measured values of the engine speed and the amount of intake air are valid, and the current driving area of the engine is a fuel economy driving area using a long duration.

In addition, in determining whether to enter the protection mode, the engine controller monitors whether the amount of current measured inside the CVVD motor controller exceeds a preset threshold current amount, and if the measured current amount exceeds a preset threshold current amount, during the exceeded It counts the time and accumulates the counted time, and when the accumulated time reaches a set threshold, it is judged as a dangerous situation, and it can be determined to enter the protection mode.

In addition, the engine controller may differently adjust the filtering strength of a low pass filter according to whether or not an eco mode is set in the protection mode.

According to an embodiment of the present invention, when a specific condition is met, a low pass filter is operated during long duration control to reduce an unnecessary duration control amount, thereby reducing current consumption of the CVVD motor controller. In addition, by preventing an overcurrent situation, damage or failure of the CVVD motor due to overcurrent can be prevented, and the frequency of entering the lymphatic home mode due to a failure or damage of the CVVD motor can be reduced.

In addition, by avoiding the overcurrent situation inside the CVVD motor controller, the lifespan of the CVVD motor and the CVVD motor controller can be further extended, and the replacement cycle of the system can be extended accordingly, so that cost reduction effects can also be expected.

1 is a schematic configuration diagram of a control device of a continuous variable valve system according to an embodiment of the present invention.
2 is experimental data showing changes in duration when target duration is controlled from a long duration direction to a short duration direction.
3 is a flowchart illustrating a method of controlling a continuously variable valve system according to an embodiment of the present invention.

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

In describing the present invention, terms used in the following specification are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

In addition, in the present specification, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or a combination thereof described in the specification, but one or more other It is to be understood that the presence or addition of features, numbers, steps, actions, components, parts, or combinations thereof, does not preclude in advance the possibility of being excluded.

In addition, terms such as first and second may be used to describe various elements, but the elements should not be limited by the terms. These terms are used only for the purpose of distinguishing one component from another component.

In addition, terms such as "... unit", "... unit", "... module" described in the specification mean a unit that processes at least one function or operation, which can be implemented by hardware or software or a combination of hardware and software. I can.

In the description with reference to the accompanying drawings, the same drawing reference numerals are assigned to the same elements, and duplicate descriptions of the same elements will be omitted. In addition, in describing the present invention, when it is determined that a detailed description of a related known technology may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

1 is a schematic configuration diagram of a control apparatus of a continuous variable valve system according to an embodiment of the present invention.

Referring to FIG. 1, a control apparatus for a continuous variable valve system according to an embodiment of the present invention includes an engine controller 10 and a CVVD motor controller 22 of a continuous variable valve duration (CVVD) system 20. The engine controller 10 adjusts the engine output so that optimal performance is exhibited by controlling the fuel injection timing, the fuel injection amount, the intake air amount, etc. in response to an accelerator pedal operation based on detection information of sensors mounted on each part of the vehicle.

The CVVD system 20 is a technology that improves the overall performance of the engine by freely adjusting the opening time of the intake valve, that is, the duration of the valve opening. In other words, CVVD is a technology that changes the time the valve is open according to the operating state of the engine, and uses the difference in speed at which the cam presses the valve when the center of rotation of the camshaft is moved to control the time the valve is open. Have.

The CVVD system 20 varies the opening time of the valve according to a target duration determined by a different value according to driving conditions such as engine rotation speed or load. For reference, the target duration (target valve opening time) is determined in the duration map 30 using the target air quantity and the engine speed as factors. That is, when the target air quantity and engine speed are input, the duration map 30 determines and outputs a target duration corresponding to the input value.

The CVVD system 20 preferably controls the valve opening time according to the control of the CVVD motor controller 22 and the CVVD motor controller 22 connected to exchange information with the engine controller 10 through CAN communication. It may be composed of a CVVD motor 24 that generates and outputs an appropriate rotational force, and a variable mechanism unit 26 having a mechanical configuration that is operated to change the rotation center of the camshaft according to the driving of the CVVD motor 24.

Since the CVVD system 20 having this configuration is a known technology, a detailed description thereof will be omitted below.

On the other hand, a long duration which makes the opening time of the intake valve relatively long is suitable for fuel economy operation. This is because if the valve duration of the intake valve is lengthened, the expansion ratio is relatively increased compared to the compression ratio and the pumping loss in the suction stroke is reduced. On the other hand, short duration, which makes the opening time of the intake valve relatively short, is advantageous for high-load operation.

However, the long duration consumes a lot of current because the control duty is larger than the short duration. In particular, in the case of the long duration control, an overcurrent flows through the CVVD motor controller 22 for fast tracking. Accordingly, in the case of the long duration control, the amount of current increases rapidly, and the CVVD motor 24 may be damaged due to accumulation of an overcurrent situation.

Therefore, the engine controller 10 applied to the embodiment of the present invention is a situation where it is necessary to protect the CVVD motor controller 22 based on the amount of current measured in the CVVD motor controller 22 during long duration control. Judge. As a result, if protection is required, a low pass filter is applied to reduce unnecessary duration control, thereby reducing the current consumption of the motor controller and preventing damage due to overcurrent.

Let's look at this in more detail.

The engine controller 10 specifically determines whether to enter a protection mode that protects the CVVD motor controller 22 from overcurrent based on the amount of current measured inside the CVVD motor controller 22. In addition, when entering the protection mode, a low pass filter is operated to filter a CVVD motor control current of a predetermined value or more during long duration control by the CVVD motor controller 22.

The determination of whether to enter the protection mode is preferably monitored whether the amount of current measured inside the CVVD motor controller 22 exceeds a preset threshold amount of current, and if the measured amount of current exceeds a preset threshold amount of current, the time for exceeding is determined. Count and accumulate the counted time. In addition, when the accumulated time reaches a set threshold, it is determined as a dangerous situation and may be determined to enter a protection mode.

Here, the threshold current amount is a threshold value of the amount of current that may damage the CVVD motor 24 when repeatedly accumulated, and may be an average value of the amount of current obtained through repeated experiments several times in the same simulation environment.

The engine controller 10 may determine whether to enter the protection mode afterwards, if the measured values of the engine speed and the amount of intake air are valid, and the current driving area of the engine is a fuel economy operation area using a long duration. have. To this end, the engine controller 10 may be equipped with one or more processors operated by a program programmed to perform each step of the control method to be described later.

When entering the protection mode, the engine controller 10 may differently adjust the filtering strength of the low pass filter according to whether or not the fuel economy mode (Eco Mode) is set. Preferably, when the drive mode is set to the fuel economy mode (Eco Mode), the filtering strength of the low pass filter is adjusted relatively high, and when the drive mode is not in the eco mode, the filtering strength of the low pass filter is adjusted relatively low. do.

Here, adjusting the filtering strength of the low pass filter relatively high means that the time constant of the low pass filter is increased to make the target duration output insensitive, the reset time of the filter is kept somewhat longer, and the filter application time is also maintained. When the time constant of the pass filter is increased to make the target duration output insensitive, the current filtering function is operated from the duty ratio region where the amount of current is relatively low, thereby significantly reducing damage to the CVVD motor due to current consumption and overcurrent.

In addition, adjusting the filtering intensity of the low-pass filter relatively low means that the time constant of the low-pass filter is increased so that only a part of the target duration output is insensitively adjusted, the reset point of the filter is kept somewhat short, and the filter application time is also kept short. , If the time constant of the low pass filter is increased and the target duration output is partially insensitive, the current filtering function is operated from a relatively high duty ratio region compared to the control that adjusts the filtering strength of the low pass filter relatively high. The followability to the driver's required torque increases.

In the fuel economy mode (Eco Mode), the frequency of long duration use increases significantly. Long duration control consumes a lot of current, and the CVVD motor 24 may be damaged due to overcurrent. Therefore, when entering the protection mode while the fuel economy mode is set, the filtering strength of the low pass filter is increased even if the fuel economy increase effect due to the long duration or the required engine torque followability is poor, thereby reducing the possibility of damage to the CVVD motor 24 due to current consumption and overcurrent. It is to reduce.

In contrast, in the case of non-eco mode, the frequency of use of the long duration is relatively low compared to the fuel economy mode. Therefore, when entering the protection mode in a state other than the fuel economy mode, the filtering strength of the low pass filter is relatively lowered, thereby securing the followability of the valve duration to the driver's required torque to meet the driver's request.

2 is experimental data showing changes in duration when target duration is controlled from a long duration direction to a short duration direction.When the valve duration is controlled in the general control mode under the same conditions, control is performed by applying a high-intensity low-pass filter in the fuel economy mode. In the case, the duration change for each case is controlled by applying a low pass filter having a relatively low intensity in the non-fuel economy mode.

Referring to FIG. 2, in the case of applying a high-intensity low-pass filter in the fuel economy mode (FIG. 2(b), control mode 2) compared to the general control mode (FIG. It can be easily seen that the duration of 2 (b) is greatly reduced. In other words, it can be interpreted that the application of the high-intensity low-pass filter reduces the current consumption and cuts off overcurrent, which may damage the CVVD motor 24.

In the case of FIG. 2 (c) in which the low-pass filter of relatively low intensity is applied (control mode 2), the level is relatively lower than that of FIG. 2 (b) in which the high-intensity low-pass filter is applied in the fuel economy mode. Compared to the general control mode of a), it can be seen that the duration is reduced in a specific long duration region (refer to the arrow in FIG. 2 (c)).

Hereinafter, a method of controlling a continuous variable valve system according to an embodiment of the present invention will be described with reference to FIG. 3.

3 is a flowchart illustrating a method of controlling a continuous variable valve system according to an embodiment of the present invention. For convenience of explanation, the configuration shown in FIG. 1 will be described with reference to the corresponding reference numerals.

Referring to FIG. 3, a method of controlling a continuous variable valve system according to an embodiment of the present invention includes determining whether the measured values of the engine speed and the intake air amount are valid (S100). In addition, if the measured values of the engine speed and the intake air amount are valid, determining whether the current driving area of the engine is a fuel economy driving area using a long duration (S200).

In step S100, preferably, if there is no error signal output from the crank angle sensor 40 and the air quantity measurement sensor 50, that is, when the crank angle sensor 40 and the air quantity measurement sensor 50 output a normal signal, the engine rotation It may be determined that the measured values of the number and the amount of intake air are valid, and in step S200, the duration map 30 using the engine speed and the amount of intake as factors may determine whether to drive fuel economy with an output (target duration value).

As a result of the determination through step S200, if the current engine operation area belongs to the fuel economy operation area, whether to enter the protection mode to protect the CVVD motor controller 22 from overcurrent based on the amount of current measured inside the CVVD motor controller 22 It is determined (S300). In step S300, when a predetermined condition to be described later is satisfied, it is determined to enter the protection mode.

In step S300, preferably, it is monitored whether the amount of current measured inside the CVVD motor controller 22 exceeds a preset threshold amount of current, and if the measured amount of current exceeds a preset threshold amount of current, the time for exceeding is counted and counted. The accumulated time is accumulated, and when the accumulated time reaches a set threshold, it is determined as a dangerous situation, and it can be decided to enter the protection mode.

When a predetermined condition for entering the protection mode (the above-mentioned condition) is satisfied and the protection mode is entered, a low pass filter is activated during target duration control to filter the CVVD motor control current above a certain value (S500). ), it is determined whether the drive mode set by the driver before (before step S500) is the fuel economy mode (Eco Mode) (S400).

In step S500 of filtering the control current, the filtering strength of the low pass filter may be differently adjusted according to whether or not the fuel economy mode determined in the previous step is set. Specifically, if the drive mode is the fuel economy mode, the filtering strength of the low pass filter is relatively high, and if the drive mode is not the fuel economy mode, the filtering strength of the low pass filter is relatively low.

In the fuel economy mode (Eco Mode), the frequency of long duration use increases significantly. Long duration control consumes a lot of current, and the CVVD motor 24 may be damaged due to overcurrent. Therefore, when entering the protection mode in the state set to the fuel economy mode, the filtering strength of the low pass filter is increased to reduce the possibility of damage to the CVVD motor 24 due to current consumption and overcurrent, although the effect of increasing fuel economy due to the long duration decreases.

In contrast, in the case of non-eco mode, the frequency of use of the long duration is relatively low compared to the fuel economy mode. Therefore, when entering the protection mode while not in the fuel economy mode, the filtering strength of the low pass filter is relatively lowered, thereby securing the followability of the valve duration to the driver's required torque.

According to the exemplary embodiment of the present invention, when a specific condition is met, a low pass filter is operated during long duration control to reduce an unnecessary duration control amount, thereby reducing current consumption of the CVVD motor controller. In addition, by preventing an overcurrent situation, damage or failure of the CVVD motor due to overcurrent can be prevented, and the frequency of entering the lymphatic home mode due to a failure or damage of the CVVD motor can be reduced.

In addition, by avoiding the overcurrent situation inside the CVVD motor controller, the lifespan of the CVVD motor and the CVVD motor controller can be further extended, and the replacement cycle of the system can be extended accordingly, so that cost reduction effects can also be expected.

In the above detailed description of the present invention, only specific embodiments according thereto have been described. However, it should be understood that the present invention is not limited to a particular form mentioned in the detailed description, but rather, it is understood to include all modifications, equivalents, and substitutes within the spirit and scope of the present invention as defined by the appended claims. Should be.

10: engine controller
20: CVVD system
22: CVVD motor controller
24: CVVD motor
26: variable mechanism part
30: duration map
40: crank angle sensor
50: air volume measurement sensor

Claims (10)

Determining whether the measured values of the engine speed and the intake air amount are valid;
Determining whether the current driving region of the engine is a fuel economy driving region using a long duration if the measured values of the engine speed and the intake air amount are valid;
Determining whether to enter a protection mode for protecting the CVVD motor controller from overcurrent based on the amount of current measured inside the CVVD motor controller in the fuel economy operation area; And
When entering the protection mode, the step of filtering a CVVD motor control current of a predetermined value or more by activating a low pass filter during target duration control.
Determining whether the measured values of the engine speed and the intake air amount are valid;
Determining whether the current driving region of the engine is a fuel economy driving region using a long duration if the measured values of the engine speed and the intake air amount are valid;
Determining whether to enter a protection mode for protecting the CVVD motor controller from overcurrent based on the amount of current measured inside the CVVD motor controller in the fuel economy operation area;
Determining whether the drive mode set by the driver is an eco mode; And
In the case of entering the protection mode, filtering a CVVD motor control current of a predetermined value or more by operating a low pass filter when controlling a target duration;
In the filtering of the control current, a method of controlling a continuous variable valve system in which the filtering strength of a low pass filter is differently adjusted according to whether or not an eco mode determined in the previous step is set.
The method according to claim 1 or 2,
In the step of determining whether the measured values of the engine speed and intake air amount are valid,
If there is no error signal output from the crank angle sensor and the air quantity measurement sensor, the control method of a continuously variable valve system, wherein the measured values of the engine speed and intake air quantity are valid.
The method of claim 2,
When the drive mode is set to Eco Mode,
A control method of a continuously variable valve system that adjusts the filtering strength of a low pass filter relatively high.
The method of claim 2,
If the drive mode is not Eco Mode,
Control method of a continuous variable valve system that adjusts the filtering strength of a low pass filter to a relatively low level.
The method according to claim 1 or 2,
In the step of determining whether to enter the protected mode,
Monitoring whether the amount of current measured inside the CVVD motor controller exceeds a preset threshold current amount,
If the measured current amount exceeds the preset threshold current amount, the time during which it has exceeded is counted and the counted time is accumulated.
A control method of a continuous variable valve system that determines to enter a protection mode by judging as a dangerous situation when the accumulated time reaches a set threshold.
Engine controller; And
Includes; a CVVD motor controller connected to exchange information with each other through CAN communication with the engine controller,
The engine controller,
Determines whether to enter the protection mode that protects the CVVD motor controller from overcurrent based on the amount of current measured inside the CVVD motor controller,
When entering the protection mode, when controlling the valve duration through the CVVD motor controller, a low pass filter is operated to filter the CVVD motor control current above a certain value,
If the measured values of the engine speed and the intake air amount are valid, and the current driving area of the engine is a fuel economy driving area using a long duration, the control device of the continuously variable valve system determines whether to enter the protection mode afterwards.
delete The method of claim 7,
The engine controller,
Monitoring whether the amount of current measured inside the CVVD motor controller exceeds a preset threshold current amount,
If the measured current amount exceeds the preset threshold current amount, the time during which it has exceeded is counted and the counted time is accumulated.
When the accumulated time reaches the set threshold, it is judged as a dangerous situation and the control device of the continuous variable valve system decides to enter the protection mode.
The method of claim 9,
The engine controller,
A control device for a continuous variable valve system that adjusts the filtering strength of a low pass filter differently depending on whether or not an eco mode is set in the protection mode.

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