KR0184434B1 - Engine brake control method of auto-transmission - Google Patents

Abstract

The present invention is to prevent the occurrence of an accident by automatically operating the engine brake when the automatic transmission vehicle is braked at a predetermined speed or more, or entered a steep slope. To this end, in the present invention, the brake pedal is operated to achieve braking of more than 80% by the potential type brake sensor, the rate of change of braking time reaching up to 80% is smaller than the set value of the economy fuel economy mode, the throttle valve by TPS When the open amount of is 0%; The shift stage of the running vehicle is forcibly switched to the engine brake mode by which the TCU is forcibly downshifted to the lower stage one step below; If the engine speed of the shift stage before and after the downshift is the same, the engine brake mode is repeated again and downshifted to the lower stage of the next stage; The engine brake control method of the automatic transmission vehicle is characterized in that the shift pattern is reduced to the economy fuel economy mode again while the running vehicle is downshifted to 1 speed.

Description

Engine brake control method of automatic transmission car

1 is a block diagram for realizing an engine brake control method for an automatic transmission vehicle according to the present invention.

2 is a flowchart showing a method for controlling engine brake of an automatic transmission vehicle according to the present invention.

[Technical Field of Invention]

The present invention relates to a method for controlling an engine brake of an automatic transmission vehicle, and more particularly, to an engine brake control method for automatically lowering the speed and performing an engine brake without manipulating a shift lever by a driver.

[Prior art]

Generally, the automatic transmission of a vehicle depends on the driving method of the vehicle (front wheel drive or rear wheel drive). It has a torque converter installed between the engine and the input shaft of the transmission, and a multi-speed gear mechanism (or power train) connected to the torque converter. Contains an element.

The hydraulically actuated friction element is controlled by a hydraulic control system that determines the flow direction of the hydraulic pressure by the transmission control unit (TCU), and inputs one of the sun gear, the planet carrier and the ring gear of the planetary gear device, respectively. By selecting power and reaction force, the required speed ratio and power are output.

The vehicle equipped with the automatic transmission made in this way is controlled by the hydraulic control system, as the driver manually selects one of the P-R-N-D-S-L range, the shift from the 1st forward to the 4th speed and the reverse 1st speed.

In a vehicle equipped with such an automatic transmission, the driver places the shift lever in the 'D' range and operates the accelerator pedal to drive the vehicle.

And when it is necessary to brake rapidly while driving or when entering a steep slope, the pedaling force applied to the accelerator pedal is removed and the brake is operated; When a greater braking force is required, the driver presses the hold switch mounted on the shift lever even in an emergency, and operates the engine brake according to the shift pattern of the hold mode depending on the vehicle speed.

[Technical problem to be achieved]

However, in the automatic transmission vehicle as described above, the engine brake control at the time of braking that requires an urgent and large braking force in a driving state of a certain speed or more; Since the brake pedal should be operated after removing the pedaling force of the accelerator, there is a problem in that the starting point of the braking is delayed.

In addition, since the engine brake state does not operate in the 2nd and 1st forwards, the driver should operate the engine brake by operating the hold switch even in an emergency situation, but it is difficult to operate due to the lack of time in the actual situation.

For this reason, a vehicle equipped with a conventional automatic transmission has a problem in that the timing of the operation of the engine brake is delayed and the braking performance is reduced, resulting in a crash accident and a drop in the steep slope.

The present invention has been made in order to solve the problems of the prior art, the present invention is to operate the brake pedal in a state of driving at a certain speed or more, the braking is made, or when entering the steep slope, the engine brake is automatically activated to operate the accident Prevent it beforehand.

[Configuration and Function of Invention]

As a means for realizing the above object, the present invention proposes an engine brake control method for an automatic transmission vehicle having a configuration described below.

That is, in the engine brake control method according to the present invention, the speed of the vehicle detected by the vehicle speed sensor is traveling at a certain speed or more, and the brake pedal is operated so that more than 80% of the braking is performed by the potential type brake sensor. When the rate of change of braking time reached to 80% is less than the set value and the opening amount of the throttle valve by the throttle position sensor TPS is ‰; Forcibly converting, by the control unit, the gear shift stage to the engine brake mode in which the gear shift stage is forcibly shifted to the lower stage under one step; After the shift stage of the vehicle is downshifted, the draw by the throttle position sensor rechecks whether the opening amount of the valve is 0%, and if the engine speed of the shift stage before and after the downshift is the same, the engine brake mode is repeatedly executed. Steps; The speed change pattern is reduced by the control unit to the economy fuel economy mode (economy mode) in which the shift is made according to the vehicle speed and the opening degree of the throttle valve by the controller.

According to the above-described control method, a vehicle equipped with an automatic transmission according to the present invention has a brake operating more than 80% while driving at a certain speed or more, braking of the brake is performed rapidly, and a signal caused by the TPS is 0%. In this case, the downshift is performed in the high-speed driving state, and the engine brake is operated, thereby shortening the braking distance of the vehicle and preventing a crash or falling.

EXAMPLE

EMBODIMENT OF THE INVENTION Hereinafter, preferred embodiment for implementing this invention is demonstrated in detail based on an accompanying drawing.

FIG. 1 is a block diagram for realizing the engine brake control method of the automatic transmission vehicle according to the present embodiment, and FIG. 2 is a flowchart showing the engine brake control method for the automatic transmission vehicle according to the present embodiment.

In this embodiment, it is determined that the driver's sudden braking intention or the vehicle has entered the steep slope, and automatically activates the appropriate engine brake, thereby improving the braking performance of the vehicle.

More specifically, in the control method of this embodiment, first, the speed of the vehicle detected by the vehicle speed sensor is traveling at an economic speed of 60 km / h or more, and the brake pedal is operated so that more than 80% of the braking is performed by the potential type brake sensor. If sudden braking is judged that the rate of change of braking time reaching up to 80% is smaller than 300ms, the setting value of the fuel economy mode, the control unit (or TCU) receives a TPS signal. When the opening amount of the throttle valve by the TPS reaches a driving state of 0%, it is recognized as a sudden braking and engine brake operation request by the driver.

In this state, the TCU checks and releases the operation of the lockup clutch which directly connects the torque converter during high-speed driving.

In addition, the TCU forcibly converts the gear shift stage of the current traveling vehicle to the engine brake mode for automatically forcibly downshifting to the lower stage one step below.

When the engine brake mode is determined in this way, the TCU controls the solenoid valve, that is, the hydraulic control system, to control the friction force TH, for example, the one-way clutch, connected between the torque converter and the transmission gear mechanism. The shift stage of the current driving state is forcibly downshifted.

In this way, after the shift stage of the vehicle is down-shifted, the TCU reconfirms whether the opening amount of the throttle valve by the throttle position sensor is 0%, and when the engine speed of the shift stage before and after downshift is the same, the solenoid The valve is controlled to force downshift to the lower stage of the downshift.

Accordingly, the TCU causes the speed change stage of the vehicle to be lowered by one speed than the traveling speed, and such an engine brake mode is repeated until the traveling speed of the vehicle is deceived.

According to this control method, a car equipped with an automatic transmission according to this embodiment is operated while a brake is operated while driving at more than one full speed. When the steep slope is entered, the shift pattern of the vehicle is automatically switched to the engine brake mode by the TCU, and the shift stage is forcibly downshifted at high speed, thereby improving the braking performance of the vehicle.

By this action, when the traveling speed of the vehicle is shifted to 1 speed, the TCU reduces the shift pattern back to the economic fuel economy mode in which the shift is made according to the vehicle speed and the opening degree of the throttle valve.

[Effects of the Invention]

Through the embodiments described above, it can be seen that the engine brake control method of the automatic transmission vehicle according to the present invention substantially solves the problems of the prior art.

That is, the present invention can automatically obtain the engine brake effect. In addition, the engine brake according to the present invention is automatically activated when the driver enters a sudden braking intention or a steep inclination, thereby providing a rapid braking to shorten the braking distance of the vehicle.

Ultimately, the effect of the present invention seeks to reduce the occurrence of accidents by improving the braking performance of the vehicle.

On the other hand, the present invention is not limited to the above-described specific preferred embodiment, and any person having ordinary skill in the art to which the invention belongs without departing from the gist of the invention claimed in the claims, various modifications Would be possible.

Claims (5)

The braking time of the brake pedal detected by the potential type brake sensor is 80% or more, and the braking time reached from 0% to 80% is less than the set value of the economy fuel mode, and the throttle valve is opened by the throttle position sensor. Determining the engine brake mode by the controller as a driving state in which the amount is 0%; And controlling the solenoid valve of the hydraulic control system by the control unit to forcibly downshift the shift stage of the traveling vehicle to a lower stage below one step. The method of claim 1, further comprising: reconfirming whether the opening amount of the throttle valve by the throttle position sensor is 0% after the shift stage of the vehicle is downshifted; And if the engine speed of the downshifted shifting stage of the shifting stage before the downshift is the same, further including the step of forcibly downshifting the shifting stage of the vehicle being driven by the control unit to the lower stage under one step again. Engine brake control method of automobile. The method of claim 2, further comprising the step of reducing the shift pattern to the economy fuel economy mode in which the shift is made according to the vehicle speed and the opening degree of the throttle valve by the control unit while the shift stage of the vehicle is downshifted to one speed. Engine brake control method of an automatic transmission vehicle. The method of claim 1, wherein the control unit further comprises the step of releasing the lock clutch of the torque converter before the downshift of the running vehicle. The engine brake control method according to claim 1, 2, 3, or 4, wherein the control unit is a transmission control unit.