KR101920390B1 - Method and apparatus for neutral control of an automatic transmission for a vehicle - Google Patents

Abstract

A neutral control method and apparatus for an automatic transmission for a vehicle are disclosed. A neutral control method and apparatus for an automatic transmission for a vehicle according to the present invention includes: determining whether a control unit satisfies a fuel cut control condition after traveling at a predetermined speed or more; Performing a fuel cut control by the control unit when the fuel cut control condition is satisfied; Confirming the engine RPM and the turbine RPM whose control portion is reduced by the fuel cut control; And when the engine RPM reaches a preset lowered fuel cut-off limit RPM, the control unit performs the neutral control and starts the fuel re-injection.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a neutral control method for an automatic transmission for a vehicle,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a neutral control method and apparatus for a vehicular automatic transmission, and more particularly to a neutral control method for a vehicular automatic transmission in which a time point of neutral control during deceleration is changed, And a device therefor.

BACKGROUND ART [0002] In general, a vehicular automatic transmission is a mechanical device that automatically optimizes a driving force generated from an engine through a gear ratio selected for each driving condition so as to match the vehicle speed and torque of the vehicle to a driver's request, to be.

The vehicle automatic transmission includes a torque converter that automatically converts torque by the kinetic energy of the fluid and a clutch and brake that are actuated by hydraulic pressure in response to the shift of the shift lever to transmit the driving force of the input shaft to the planetary gear set A friction mechanism, and a planetary gear set that is driven by a friction mechanism to adjust the speed ratio according to the running speed and load of the vehicle, and an actuator that drives the friction mechanism by hydraulic pressure.

These components have been developed and applied in different forms according to the manufacturers of each automobile. Currently, 4 to 6 speed automatic transmissions are mainly used, and the improvement of the fuel efficiency and the use of the engine driving force improve the power performance Therefore, automatic transmissions of more than 7 speed are realized.

Meanwhile, in response to the era of high oil prices, improvement of vehicle fuel efficiency has become an important issue for automobile manufacturers. Accordingly, an effort is being made to improve fuel economy in an automatic transmission vehicle, and there is a neutral control method as an example.

The neutral control is a control method in which the fuel economy is improved by lowering the engine load by lowering the engine load by turning the clutch to a semi-neutral state at the D stop in the automatic transmission vehicle constituted by the planetary gear set. In other words, when the vehicle is stopped for a short period of time such as during signal waiting, most drivers only stop the vehicle by stepping on the brake pedal, but do not convert the shift lever to the N-step. That is, in this situation, after the vehicle is completely stopped, the transmission is controlled to be neutral after a predetermined time if it meets the stop condition and the temperature condition.

Further, in the case of decelerating for stopping, fuel cut control for cutting off the fuel supplied to the engine is performed as an additional technique for improving fuel economy. When the engine RPM is reduced to a certain value or less, Fuel re-injection and idle control, and then performs neutral control.

However, as shown in FIG. 1, when the vehicle is stopped, the number of revolutions of the turbine is drastically lowered, causing a slip phenomenon of the engine and the turbine. There is a problem that the load on the engine side increases due to the slip phenomenon of the engine and the turbine and the fuel consumption of the engine increases.

That is, when the idle control of the engine is unstable, an uncomfortable feeling may occur due to excessive fuel injection and engine RPM increase during load increase portion or fuel re-injection.

As a background technique of the present invention, there is an " automatic transmission control device ", which is registered in Korean Registered Patent No. 10-1617451 (registered on Apr. 26, 2016).

According to one aspect of the present invention, there is provided an automatic transmission for a vehicle, which is designed to overcome the above-mentioned problems, A control method thereof, and a device therefor.

A neutral control method for an automatic transmission for a vehicle according to an aspect of the present invention includes: determining whether a control unit satisfies a fuel cut control condition after traveling over a predetermined speed; Performing the fuel cut control when the fuel cut control condition is satisfied; Confirming an engine RPM and a turbine RPM in which the control unit is reduced by the fuel cut control; And when the engine RPM reaches a predetermined lowered fuel cut-off lower limit RPM, the control unit performs neutral control and starts fuel re-injection.

In the step of determining whether the fuel cut control condition of the present invention is satisfied, the control unit determines that the opening amount of the accelerator pedal received from the accelerator pedal detecting unit is equal to or smaller than the threshold value, and the position of the shift lever, The control unit determines that the fuel cut control condition is satisfied.

The engine RPM inputted from the engine speed detecting portion and the turbine RPM received from the turbine speed detecting portion during the neutral control are compared with the reference slip And the hydraulic pressure is controlled so as to be maintained at a predetermined amount.

The present invention further includes a step of releasing the neutral control and performing the shift control when the control unit re-starts after the vehicle is stopped.

According to another aspect of the present invention, there is provided a neutral control apparatus for an automatic transmission for a vehicle, comprising: an engine speed detection unit for detecting an engine speed of a vehicle; A fuel control driver for supplying and blocking fuel required for the engine of the vehicle; A shift control driver for performing a gear shift and an oil pressure control of the automatic transmission of the vehicle; And when the fuel cut control condition is satisfied after determining that the fuel cut control condition is satisfied after the vehicle travels over a predetermined speed, the fuel cut control is performed, and the engine RPM inputted from the engine speed detection section decreases, And a control unit for performing neutral control through the shift control drive unit and initiating fuel re-injection through the fuel control driver when a fuel cut reaches a lower limit RPM.

In the present invention, when the opening amount of the accelerator pedal inputted from the accelerator pedal detecting section is equal to or smaller than the threshold value and the position of the shift lever inputted from the shift lever detecting section is located at the D-stage, it is judged that the fuel cut control condition is satisfied .

In the present invention, the controller may control the oil pressure such that the engine RPM received from the engine speed detector and the turbine RPM received from the turbine speed detector are maintained at the reference slip amount during neutral control.

In the present invention, the control unit releases the neutral control and performs the shift control when re-starting after the vehicle is stopped.

The neutral control method and apparatus of an automatic transmission for a vehicle according to an embodiment of the present invention can change the timing of neutral control during deceleration to enable stable engine idle control in an increased load state, And the fuel economy can be improved.

The neutral control method and apparatus of an automatic transmission for a vehicle according to an embodiment of the present invention can prevent excessive fuel injection and engine RPM rise by performing neutral control during re-injection after fuel cut control, It is possible to reduce discomfort.

In addition, by performing the fuel cut control in the steel plate mode, it is possible to reduce the load and the resistance element, thereby improving the deceleration driving performance due to the traveling in the other direction.

Fig. 1 is a diagram showing an example of a neutral control method and apparatus for a conventional automatic transmission for a vehicle.
2 is a diagram illustrating an example of a neutral control method and apparatus for an automatic transmission for a vehicle according to an embodiment of the present invention.
3 is a block diagram showing a neutral control apparatus for an automatic transmission for a vehicle according to an embodiment of the present invention.
4 is a flowchart for explaining a neutral control method of an automatic transmission for a vehicle according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a neutral control method and apparatus for an automatic transmission for a vehicle according to an embodiment of the present invention will be described with reference to the accompanying drawings. In this process, the thicknesses of the lines and the sizes of the components shown in the drawings may be exaggerated for clarity and convenience of explanation.

In addition, the terms described below are defined in consideration of the functions of the present invention, which may vary depending on the intention or custom of the user, the operator. Therefore, definitions of these terms should be made based on the contents throughout this specification.

2 is a diagram illustrating an example of a neutral control method and apparatus for a vehicular automatic transmission according to an embodiment of the present invention, and Fig. 3 is a diagram showing an example of a neutral control method and apparatus for a vehicle automatic transmission according to an embodiment of the present invention. A neutral control device for a vehicular automatic transmission according to an embodiment of the present invention will now be described with reference to the accompanying drawings.

3, the neutral control apparatus for an automatic transmission for a vehicle according to an embodiment of the present invention includes an operation information detector 100, a controller 200, a fuel control driver 300, and a shift control driver 400, .

The operation information detecting unit 100 detects all the information necessary for driving the vehicle and outputs the information to the control unit 200. The operation information detecting unit 100 includes an acceleration pedal detecting unit 110, a shift lever detecting unit 120, a vehicle speed detecting unit 130, And may include a detection unit 140 and a turbine speed detection unit 150.

The accelerator pedal detecting unit 110 detects the opening amount of the accelerator pedal of the vehicle and transmits the opening amount of the detected accelerator pedal to the control unit 200 so that the driver can judge the degree of depression of the accelerator pedal. That is, the accelerator pedal detector 110 continuously measures the amount of opening of the accelerator pedal, and transmits the monitored signal to the controller 200. When the accelerator pedal is fully depressed, the opening amount of the accelerator pedal is 100%, and when the accelerator pedal is not depressed, the opening amount of the accelerator pedal may be 0%.

In addition, the accelerator pedal detector 110 may measure the position value of the accelerator pedal including the accelerator position sensor (APS), and may use a throttle position sensor (TPS) mounted on the intake passage. Accordingly, the opening amount of the throttle valve sensed by the throttle valve opening sensor may be the opening amount of the accelerator pedal sensed by the accelerator pedal detecting unit 110. [

The shift lever detector 120 detects the position of the current shift lever by operating the shift lever of the driver. That is, when the shift lever is positioned at one of the positions, the control unit 200 transmits the position of the shift lever to the control unit 200 so that the control unit 200 performs the shift. Accordingly, the control unit 200 receives the position of the shift lever from the shift lever detection unit 120, and can determine which shift position is to be shifted to the next shift position after the current shift position when the shift lever is moved.

At this time, the shift lever is generally formed with various types of shift patterns, and the shift of the vehicle is performed by the driver operating the shift lever according to the shift pattern. Such a shift pattern exists not only in a manual transmission but also in an automatic transmission, and has a unique shift pattern for each company that produces a shift lever and a transmission. Generally, the automatic transmission has a shift pattern in the order of P-R-N-D. Depending on the case, a shift step may be further provided in the order of 3-2-1 after the D range.

The vehicle speed detector 130 detects the speed of the vehicle and determines the movement of the vehicle. Also, the vehicle speed detector 130 may be installed on the wheel of the vehicle to detect the speed of the wheel, calculate the speed of the vehicle in proportion to the detected speed, and transmit the calculated speed to the controller 200. The speed sensor And may transmit a predetermined electric signal to the control unit 200.

The engine speed detecting section 140 detects the engine speed and provides the engine speed to the control section 200. The engine speed detecting section 140 detects the engine speed from a phase angle change of a crankshaft or a camshaft, It is possible to provide information to the control unit 200. [

The turbine speed detector 150 detects the turbine speed of the torque converter of the transmission, that is, the input speed of the transmission, and provides information on the detected speed to the controller 200. At this time, the turbine speed may vary depending on the running state of the vehicle.

Also, although not shown, the operation information detecting unit 100 includes a transmission output speed sensor for detecting the output speed of the transmission, an acceleration sensor for detecting the vehicle acceleration, a brake pressure sensor for detecting the pressure under pressure in the vehicle braking, And a water temperature sensor for detecting the water temperature.

The fuel control driver 300 supplies and blocks the fuel required for the engine and controls the fuel valve (not shown) to shut off or supply the fuel by the control signal of the controller 200. The fuel control driver 300 may be installed in a fuel tank (not shown) together with a fuel pump (not shown), but it may be installed anywhere in the vicinity of a fuel tank or in a fuel line such as an engine room. Therefore, the fuel control driver 300 may control only the fuel pump to supply and block the fuel without configuring the fuel valve, and may also operate with the fuel valve provided in the fuel line without separately controlling the fuel pump. However, it is preferable that the fuel pump and the fuel valve are preferably provided together so as to quickly and accurately correct the interruption of the fuel.

The transmission control drive unit 400 performs gear shifting and oil pressure control of the automatic transmission and is connected to the control unit 200 through CAN communication or a dedicated communication interface to exchange control information, The engagement side friction element and the release side friction element are operated to control the engagement of the target speed change stage.

In addition, the shift control drive unit 400 selectively controls the flow path of the hydraulic oil supplied to the friction engagement elements by controlling the hydraulic control solenoid valve that controls the hydraulic pressure of the hydraulic oil generated by the oil pump (not shown) .

At this time, the hydraulic control solenoid valve functions to control the hydraulic pressure to switch the flow path of the flow path switching valve. The hydraulic control solenoid valve is a normally open type solenoid valve with high output pressure and low output pressure with supply of power and low output pressure with no power supply, A normally closed type solenoid valve may be used.

Meanwhile, in the process of transmitting the simple power (torque) of the automatic transmission vehicle, the power is transmitted in the order of the engine, the engine rotation shaft, the torque converter (turbine), the transmission input shaft, the clutch, the transmission output shaft, and the wheels (drive shaft). That is, the engine rotational force according to the engine rotational speed detected by the engine rotational speed detecting unit 140 can be changed and transmitted according to the power transmission rate through the torque converter.

At this time, when the vehicle is in the stopped state (shift lever P, N stages), the power is not transmitted to the drive shaft because the clutches of the transmission are not attached to each other. However, because the power is transmitted to the input shaft of the transmission, the engine RPM detected by the engine speed detector 140 and the RPM of the turbine RPM detected by the turbine speed detector 150 are similar.

Then, when the vehicle is in the running state (the shift lever D side), the clutches of the transmission engage with each other. At this time, the shift control driver 400 adjusts the hydraulic pressure using the hydraulic valve so that the clutches of the transmission are engaged with each other. That is, by connecting the clutch, the engine power is transmitted to the drive shaft. At this time, the engine RPM detected by the engine speed detector 140 and the RPM of the turbine RPM detected by the turbine speed detector 150 are similar.

On the other hand, when the vehicle is in a stopped state by stepping on the brake at the end of the shift lever D, the clutches of the transmission are engaged with each other because the shift lever is located at the D-end. However, since the user has pressed the brake, the vehicle wheels are locked, and the drive shaft connected to the wheels is not rotated, so that the input shaft connected to the clutch also does not rotate. That is, the power output from the engine is transmitted to the impeller portion of the torque converter, but not to the turbine portion. Accordingly, as shown in FIG. 1, the turbine RPM is rapidly reduced at the moment when the vehicle is stopped, resulting in a difference from the engine RPM, resulting in a slip phenomenon.

In this embodiment, in order to reduce an increase in the load on the engine side due to the occurrence of the slip phenomenon due to the difference between the turbine RPM and the engine RPM, and an increase in fuel consumption of the engine, the neutral control is automatically performed even if the shift lever is positioned at the D- So as to perform the control to change the start time of the vehicle to the pre-stop.

That is, the control unit 200 determines whether the fuel cut control condition is satisfied after the vehicle travels at a predetermined speed or more, and performs fuel cut control when the fuel cut control condition is satisfied. Then, the control unit 200 confirms whether the engine RPM inputted from the engine speed detection unit 140 has decreased and reaches the preset lower limit of the fuel cut-off RPM. At this time, when the engine RPM reaches the fuel cut lower limit RPM, the controller 200 performs the neutral control through the shift control driver 400 and simultaneously starts the fuel re-injection through the fuel control driver 300.

More specifically, the control unit 200 determines that the opening amount of the accelerator pedal input from the accelerator pedal detecting unit 110 is equal to or less than the critical value, for example, 0%, and the position of the shift lever, which is input from the shift lever detecting unit 120, , It can be determined that the fuel cut control condition is satisfied.

That is, when the vehicle is traveling at a predetermined speed or more and traveling at a predetermined reference engine RPM or more, the control unit 200 determines that the opening amount of the accelerator pedal detected by the accelerator pedal detecting unit 110 is less than the threshold value, That is, when the foot of the driver is distanced from the accelerator pedal, deceleration occurs, and at this time, the fuel cut control is performed.

2, the control unit 200 confirms whether the engine RPM has decreased due to the fuel cut control and reaches the fuel cut lower limit RPM, and when the fuel cut lower limit RPM is reached, It can be judged as the re-injection timing. That is, before the vehicle stops, the fuel is injected into the neutral state at the time of fuel re-injection.

At this time, the controller 200 controls the oil pressure so that the engine RPM received from the engine speed detector 140 and the turbine RPM received from the turbine speed detector 150 are maintained at a predetermined reference slip amount at the time of neutral control . That is, from the time of deceleration, the difference between the engine RPM and the turbine RPM can be minimized until the vehicle is completely stopped due to the brake, thereby reducing the load increase due to engine and turbine slip.

Then, the control unit 200 can maintain the neutral control until the vehicle stops, release the neutral control at the time of restart, and perform the shift control. That is, when the amount of opening of the accelerator pedal received from the accelerator pedal detecting unit 110 exceeds the threshold value, the control unit 200 resumes the clutch oil pressure to cancel the neutral control, and transmits the shift signal to the shift control drive unit 400 To be shifted to the target speed change stage.

Therefore, the fuel efficiency is further improved in the driving mode where frequent stops and rashes occur in the city center.

FIG. 4 is a flowchart for explaining a neutral control method for an automatic transmission for a vehicle according to an embodiment of the present invention. Referring to FIG. 4, a neutral control method for a vehicular automatic transmission will be described below.

4, in the neutral control method for an automatic transmission for a vehicle according to an embodiment of the present invention, the control unit 200 first determines whether the fuel cut control condition is satisfied after the vehicle has traveled over a predetermined speed (S100).

At this time, it is possible to determine whether the fuel cut control condition is satisfied through the opening amount of the accelerator pedal and the position of the shift lever.

That is, the control unit 200 determines whether the opening amount of the accelerator pedal received from the accelerator pedal detecting unit 110 is equal to or less than the threshold value, for example, 0%, and the position of the shift lever, which is input from the shift lever detecting unit 120, can do.

At this time, if the fuel cut control condition is not satisfied, the control is terminated and the current control is maintained.

In step S100, when the fuel cut control condition is satisfied, the control unit 200 performs the fuel cut control (S200).

That is, when the vehicle is traveling at a predetermined speed or higher and traveling at a predetermined reference engine RPM or higher, the controller 200 determines that the opening amount of the accelerator pedal detected by the accelerator pedal detector 110 is less than or equal to the threshold value, That is, when the foot of the driver is distanced from the accelerator pedal, deceleration occurs, and at this time, the fuel cut control is performed.

At this time, the predetermined reference engine RPM may include a fuel cut upper RPM that is separately set in addition to the fuel cut lower limit RPM. Also, the predetermined reference engine RPM may be set differently depending on the cooling water temperature and the number of gear stages. For example, the lower the coolant temperature and the lower the gear, the higher the reference engine RPM.

After step S200, the control unit 200 determines whether the engine RPM decreases due to the fuel cut control and reaches the fuel cut lower limit RPM (S300).

That is, the controller 200 determines whether or not the fuel cut-off lower limit RPM is reached and determines the neutral start and the fuel re-injection timing.

At this time, if the engine RPM exceeds the fuel cut lower limit RPM, the control unit 200 returns to step S200 to continue the fuel cut control.

In step S300, when the engine RPM reaches the fuel cut lower limit RPM, the control unit 200 starts the neutral control and the fuel re-injection (S400).

That is, the control unit 200 determines that the time point at which the fuel cut reaches the lower limit RPM is the neutral start and the fuel re-injection timing, and initiates neutral control and fuel re-injection. That is, before the vehicle stops, the fuel is injected into the neutral state at the time of fuel re-injection.

At this time, the controller 200 controls the oil pressure so that the engine RPM received from the engine speed detector 140 and the turbine RPM received from the turbine speed detector 150 are maintained at a predetermined reference slip amount at the time of neutral control . That is, from the time of deceleration, the difference between the engine RPM and the turbine RPM can be minimized until the vehicle is completely stopped due to the brake, thereby reducing the load increase due to engine and turbine slip.

Next, the control unit 200 determines whether the vehicle is stopped after the vehicle is stopped (S500).

At this time, if the vehicle is stopped without being restarted after the vehicle is stopped, the routine returns to step S400 to continue the neutral control and the fuel re-injection.

That is, the control unit 200 can maintain the neutral control until the vehicle stops, and can cancel the neutral control and perform the shift control at the time of the restart. In other words, when the opening amount of the accelerator pedal input from the accelerator pedal detecting unit 110 exceeds the threshold value, the control unit 200 resumes the clutch oil pressure to cancel the neutral control, To be shifted to the target speed change stage.

As described above, the neutral control method and apparatus for an automatic transmission for a vehicle according to an embodiment of the present invention allow stable engine idle control in a load increase state by changing the time point of neutral control at the time of deceleration, There is an effect that the fuel consumption can be reduced without an additional device, and the fuel consumption can be improved.

The neutral control method and apparatus of an automatic transmission for a vehicle according to an embodiment of the present invention can prevent excessive fuel injection and engine RPM rise by performing neutral control during re-injection after fuel cut control, It is possible to reduce discomfort.

In addition, by performing the fuel cut control in the steel plate mode, it is possible to reduce the load and the resistance element, thereby improving the deceleration driving performance due to the traveling in the other direction.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. I will understand.

Accordingly, the true scope of the present invention should be determined by the following claims.

100: operation information detection unit 110: accelerator pedal detection unit
120: Shift lever detecting unit 130:
140: engine speed detector 150: turbine speed detector
200: control unit 300: fuel control driving unit
400: Shift control driver

Claims (8)

Determining whether the control unit satisfies the fuel cut control condition after traveling at a predetermined speed or more;
Performing the fuel cut control when the fuel cut control condition is satisfied;
Confirming an engine RPM and a turbine RPM in which the control unit is reduced by the fuel cut control; And
And when the engine RPM decreases and reaches a predetermined fuel cut lower limit RPM, the control unit performs neutral control and initiates fuel re-injection,
Further comprising the step of: maintaining the neutral control until the vehicle stops, releasing the neutral control when the vehicle is stopped again, and performing the shift control. .
The method according to claim 1,
In the step of determining whether the fuel cut control condition is satisfied,
Wherein,
When the opening amount of the accelerator pedal received from the accelerator pedal detecting section is equal to or smaller than the threshold value and the position of the shift lever inputted from the shift lever detecting section is located at the D stage, it is determined that the fuel cut control condition is satisfied / RTI >
The method according to claim 1,
In the step of performing the neutral control and simultaneously starting the fuel re-injection,
Wherein,
Wherein the control unit controls the oil pressure so that the engine RPM inputted from the engine speed detecting unit and the turbine RPM inputted from the turbine speed detecting unit are maintained at the reference slip amount during the neutral control.
delete An engine speed detecting section for detecting an engine speed of the vehicle;
A fuel control driver for supplying and blocking fuel required for the engine of the vehicle;
A shift control driver for performing a gear shift and an oil pressure control of the automatic transmission of the vehicle; And
When the fuel cut control condition is satisfied after determining that the fuel cut control condition is satisfied after the vehicle travels at a constant speed or more, fuel cut control is performed, and the engine RPM input from the engine speed detection unit is decreased And a control unit for performing neutral control through the shift control drive unit when the fuel cut-off lower limit RPM is reached, and initiating fuel re-injection through the fuel control drive unit,
Wherein,
Wherein the neutral control is maintained until the vehicle stops, and the neutral control is released when the vehicle is restarted after the vehicle is stopped, thereby performing the shift control.
6. The method of claim 5,
Wherein,
When the opening amount of the accelerator pedal received from the accelerator pedal detecting section is equal to or smaller than the threshold value and the position of the shift lever inputted from the shift lever detecting section is located at the D stage, it is determined that the fuel cut control condition is satisfied .
6. The method of claim 5,
Wherein,
Wherein the control unit controls the oil pressure so that the engine RPM inputted from the engine speed detecting unit and the turbine RPM inputted from the turbine speed detecting unit are maintained at the reference slip amount during the neutral control. delete

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