What is buzzing when you turn on the auto hold tiguan. hold button on automatic transmission. Technical features and purpose of the hold button on the automatic transmission

Novice motorists, not understanding the purpose of the HOLD button, prefer not to turn on the special mode of operation of the "machine". The nuances of using the button's capabilities are interpreted by many drivers in their own way, causing controversy in automotive forums.

Technical features of the HOLD button

The purpose of the button is clear from the translation of the function name into Russian (from English HOLD translates as "fixation", "hold"). The function limits the range of speeds involved automatic transmission in difficult conditions. Such modes of automatic transmission for imported brands can be designated by an "asterisk", "snowflake".

Structurally, the activation of the mode gives a command to the electronic control unit of the automatic transmission to limit the inclusion of lower or higher speeds. The main function of the mode, starting off at second speed (excluding the first), is designed to prevent slipping during a soft start on slippery surfaces.

The nuances of using a special automatic transmission mode

The button for the special operating mode of the automatic transmission for various models is located on the gear selector, next to it, on the center console "torpedo". Pressing the button is accompanied by the display of the same inscription on the computer screen (indicator of automatic transmission modes, speedometer dial).

To use the special mode correctly, you need to carefully read the manual of your car. Experienced drivers use the Hold button in a variety of situations. Starting off in second gear is used in winter on snow, ice cover. After shifting to third gear, the transmission does not change to higher speeds. The property of a button to enable the locking mode while driving is used:

when climbing up on slippery slopes;
when braking the engine on slopes;
when overtaking;
in traffic jams.

Standard designation of driving modes for European and Japanese models provides a combination of basic modes with the HOLD button. The S + HOLD combination is used on long descents for engine braking, the mode works in second gear. D + HOLD mode is used when driving in traffic jams, driving slowly in heavy traffic.

Gas consumption increases when the HOLD button is used, so the instructions recommend disabling the function during normal driving (except winter use). Expensive models have automatic shutdown functions.

Leave a request for diagnostics

Auto Hold keeps the vehicle stationary even when the brake pedal is not depressed after the driver forces the vehicle to a complete stop by pressing the brake pedal.

1. Close the driver's door, bonnet and boot lid, fasten the seat belt or press the brake pedal, then press the "Auto Hold" button. The white AUTO HOLD indicator lights up and the system enters standby mode.

2. When the vehicle comes to a complete stop with the brake pedal, the “AUTO HOLD” indicator changes from white to green.

3. The vehicle remains stationary even when the brake pedal is released.

4. When the EPB is turned on, the auto hold system is turned off and the indicator light turns white.

Completion

If you press the accelerator pedal with the gear lever in the “R” (Reverse), “D” (Drive) or sport mode, Auto Hold is automatically reset and the vehicle starts moving. The indicator color changes from green to white.

CAREFULLY

When starting off (by pressing the accelerator pedal) and the automatic hold system is on, always pay close attention to the surrounding traffic situation. For a smooth start, press the accelerator pedal slowly.

To stop the automatic hold system, press the Auto Hold switch with the brake pedal depressed. The “AUTO HOLD” indicator goes off.

To terminate the automatic hold system when the vehicle is stationary, press the “Auto Hold” switch with the brake pedal depressed.

FOR YOUR INFORMATION

The auto hold system does not work under the following conditions:

- the hood is open;
- the trunk lid is open;
- the gear shift lever is in the "P" (Park) position;
- the electric parking brake is on;
For safety reasons, the automatic hold system automatically switches to the electric parking brake mode in the following cases:
- the driver's seat belt is not fastened when the driver's door is open;
- the hood is open;
- the trunk lid is open;
- the car is stationary for more than 10 minutes;
- the car is standing on a steep slope;
- the car has moved several times.
In these cases, the brake warning lamp comes on to signal that the electric parking brake system is automatically engaged, the “AUTO HOLD” indicator changes from green to white, an alarm sounds and a message is displayed. Before driving, press the brake pedal, check the traffic situation near the vehicle and manually release the parking brake using the EPB switch.
The yellow color of the “AUTO HOLD” indicator indicates a malfunction of the automatic hold system. Have an authorized Kia dealer check the system.

CAREFULLY

Slowly depress the accelerator pedal when the vehicle starts to move.
For safety reasons, cancel Auto Hold when driving downhill, reversing, or parking.

ATTENTION

If there is a fault with the driver's door, engine hood or boot lid, open the fault detection system, the Auto Hold system may not work properly. Have an authorized Kia dealer check the system.

One of the main parts of the gearbox is the oscillating gear. It is mounted on the hub of the drive pulley at an angle and therefore wobbles as it rotates. It is kept from turning relative to the gearbox housing by two levers sliding along the inner walls of the gearbox housing. When driving, only a pair of swinging gear teeth constantly mesh with the driven gear teeth. Moreover, the swinging gear has one more tooth than the driven gear, so there is no full engagement. Only one tooth of the swinging gear with the lateral surface presses on the counterpart of the driven, turning the latter by a small angle. As a result, for a full revolution of the toothed pulley, the driven gear is displaced by only one tooth.

The driver can “tighten” the electromechanical parking brake even with the engine off, but release it only by turning on the ignition and pressing the brake pedal.

If the engine is running, the driver has closed the door and buckled up, the handbrake will turn off automatically when the accelerator is pressed. In this case, the longitudinal body roll sensor recognizes whether the vehicle is on an incline, takes into account the position of the clutch and accelerator pedals, and holds the brakes to prevent the vehicle from rolling backwards.

Piston with screw pair:

1 - piston brake cylinder;

2 - push nut;

3 - spindle.

The helical pair converts the rotation of the driven gear into a translational movement of the rod. He presses on the brake piston, bringing the pads to the disc. The effort is controlled by the parking brake control unit according to the current consumption. As soon as the value reaches the required value, the electric motor will shut off. When removed from the parking brake, the motor rotates in the opposite direction, the rod moves back, and the piston moves due to the elasticity of the sealing cuff.

Often, next to the electric handbrake key, there is another one that turns on the Auto Hold function. It makes life much easier. For example, pushing in traffic jams in a car with an automatic machine, you do not need to keep your foot on the brake. The car stopped, the driver releases the pedal, and the valves of the ABS unit remain closed - the pressure in the circuits is high, the pads compress the brake discs. If the stop lasts more than a couple of minutes, the ABS will transfer watch to the parking brake.

The car will get on the handbrake earlier - if, for example, the driver unfastens his seat belt, opens the door or turns off the ignition.

Electric parking brake: No longer hand brake

Electricity is replacing mechanics everywhere. Even the parking brake cable has been replaced by wires. A short lecture on how the new generation handbrake works and how it works is delivered by Gennady Emelkin.

The advantages of an electromechanical parking brake over a conventional one are obvious. Instead of a bulky lever between the front seats, a compact button. There is no need to drag cables and rods through the entire bottom - it is enough to connect the control unit to the common electric bus and supply the brakes on the rear wheels with electric motors. In other words, this design simplifies layout and assembly, and reduces production time and costs. In addition, during operation, there is no need for adjustments - the electronics monitors the gap between the pads and the disc every time the parking brake is applied. And if it is rarely used (for example, on cars with automatic devices), then the system tightens the handbrake every 1000 km.

The algorithm of work on most cars is similar. The driver presses the button, which sends a signal to the parking brake control unit. If the car is stationary or is moving slower than 7-10 km / h, the electric motors are switched on, activating the brakes. At higher speeds, the ABS unit activates the hydraulic pump - the pressure in the brake circuits increases. The car slows down and then hits the handbrake.

The driver can “tighten” the electromechanical parking brake even with the engine off, but release it only by turning on the ignition and pressing the brake pedal. If the engine is running, the driver has closed the door and buckled up, the handbrake will turn off automatically when the accelerator is pressed. In this case, the longitudinal body roll sensor recognizes whether the vehicle is on an incline, takes into account the position of the clutch and accelerator pedals, and holds the brakes to prevent the vehicle from rolling backwards.

The parking brake is an important and necessary structural element of a car. With its help, the car is fixed in place during the parking period, and spontaneous rollback is also prevented. vehicle... The classic layout of the parking brake is mechanical, with a cable system and a control lever, but in modern cars the use of an electromechanical unit with the auto hold function is becoming more frequent. Auto hold parking brake - what is it and how does it work?

Auto Hold brake functions

Electromechanical vehicle brakes are often referred to as EPBs in foreign car manuals. The acronym stands for Electromechanical Parking Brake. Its functions:

fixing the car when parked;
prevention of rollback in a stationary state, as well as when starting from a slope;
emergency braking if the main braking system for some reason does not work.

Vehicles equipped with an electromechanical brake are equipped with an interior activation button, designated Auto Hold. An example of such a button:

Sometimes there is another image - a “parking brake” pictogram with the letter A inscribed in it:

Module device

General structure

An electromechanical brake is usually placed on the rear axle. It includes:

brake mechanism;
brake drive;
and a controlling system.

The brake mechanism is activated standard for a specific car. Some structural modifications are made to the working cylinders, and an electromechanical drive is mounted on the support.

The wheel mechanism of an electromechanical parking brake can be depicted schematically as follows:

Number 1 denotes a piston, 2 - an electric motor, number 3 in the figure shows a drive belt, and 4 - a gearbox.

Gearbox device:

Legend:

number 1 - driven gear of the unit;
number 2 - the output shaft of the device;
number 3 - denotes the pulley hub;
number 4 - the pulley itself;
number 5 is a schematic representation of the engagement of the teeth of the oscillating and driven gears.

The swinging gear is an important structural element. It is mounted on the hub at a certain angle. This provides it with the ability to swing, and two special leashes protect the gear from full rotation in relation to the housing. When movement occurs, two teeth of this gear engages with the driven one, while, due to the difference in the number of teeth, the engagement is not complete. The revolution of the pulley displaces the driven gear by only one tooth.

A gear belt drive connects the motor to the gearbox. The latter significantly reduces the speed at which the output shaft rotates, which gives the system the ability to develop the necessary force for the brake to function.

Next important element- a piston with a special screw pair, consisting of the actual brake cylinder piston (1), a pressure nut (2) and a spindle (3):

The rotation of the driven gear is converted into a forward stroke of the rod due to the helical pair. The rod puts pressure on the piston, which moves the pads towards wheel rim... The generated pressure force is determined by the ECU of the electromechanical vehicle brake, guided by the readings of the value of the electric current consumed by the system. The drive motor will shut off when the current reaches the programmed value.

If the car is removed from the previously set "parking brake", the motor will rotate in the opposite direction and retrace the stem, removing the braking force.

Auto hold

Some car models are equipped with an auto hold function activated by pressing the Auto Hold key. This is an extension of the logic of the electromechanical brake: the brake pads continue to compress the discs even after the brake pedal is released.

Functioning principle

The Auto Hold function has become standard for a number of Volkswagen cars (VW Touareg, VW Tiguan, VW Passat, VW Golf families), Korean KIA, BMW, and some others. In its work, this system relies on the readings of many sensors:

the slope analyzer on which the vehicle is located:
the position of the accelerator and (for manual gearboxes) the clutch pedal;
evaluating the speed of releasing the pedal;
estimating the speed of the car if the vehicle is moving.

All this is needed to timely turn on and off the brake.

In general, the system works like this:

the driver applies the brake and presses the Auto Hold button. The ECU activates the system and enters the standby state;
when the car comes to a complete stop, the system goes into active mode, and even when the brake pedal is released, the vehicle remains stationary;
if the car owner turns on the EPB, the Auto Hold module will go into a standby state.

In cars of the Volkswagen concern, AutoHold has several sub-functions:

standing start assistant;
motion assistant in Stop-n-Go mode;
autoactivation of the electromechanical brake.

By removing his foot from the brake pedal, the driver no longer gives the command to lock the wheels with the brakes, but the pressure in the line continues to be maintained. If the ABS detects a downhill movement (tilt sensors, rolling sensors, etc.), the brake ECU will command an increase in pressure until a standstill occurs. Then, when the driver engages the clutch (for "mechanics") or adds gas (for "automatic"), Auto Hold will remove the braking force.

In the parking mode, the system switches from hydraulic brakes to the electromechanical part 3 minutes after starting to hold the machine, when unfastening the belt, turning off the engine ignition or opening the doors.

Other models may have different features of this mode.

Turn off Auto Hold by pressing the corresponding button again.

Working conditions

"Auto hold" is activated when several conditions are met (may differ for different models machines of a certain manufacturer):

the driver's door is closed;
wearing a seat belt;
the vehicle engine is running;
the Auto Hold key on the panel is pressed.

The electric parking brake is activated when:

the function is enabled from the key;
the engine ignition is turned off;
the door on the driver's side is open;
the belt is unfastened.

A number of makes and models of cars require re-enabling autohold after re-starting the engine. In other situations, the function works all the time until the engine is started, for example, in the VW Golf 2.

To keep the vehicle standing on a slope, the system needs to create high pressure in the brake lines. If the driver wishes to drive off in this case, the pressure must be overcome to start driving. The brake is released by the control unit only when the engine reaches the required power to prevent rolling.

The system does not enter auto-hold mode:

if the driver's belt is not fastened and the door on his side is not closed;
the trunk is open;
the hood will open;
the automatic transmission selector is moved to the Parking position;
the electromechanical parking brake is active.

The latter turns on independently when:

open trunk, hood;
the sensors detected a parking lot on a slope;
the driver's door is open, the seat belt is not fastened;
there have been several movements of the vehicle;
the machine is stationary for 3 to 10 minutes.

Advantages of Auto Hold brakes and disadvantages of the system

The electromechanical brake system with the optional Auto Hold extension has a number of significant advantages:

the car owner experiences less stress during vehicle operation. This is especially important in urban driving mode, with traffic jams and frequent acceleration-stopping cycles, because you no longer need to constantly keep the brakes pressed;
"Autohold" helps to stop and start moving on slopes, the car does not roll;
support of the control unit automatically keeps the car in one place, while there is no difference why the car stopped;
the programmed mode of turning on the electric parking brake when the driver's door is opened, the belt is unfastened, the engine is muffled, provides additional security of people;
activation is provided by a convenient button that replaces the bulky and inconvenient lever;
the electric brake does not need to be adjusted during normal operation, the system turns off automatically (the situation "forgot to remove the handbrake" is excluded).

But there are also some disadvantages. Among those:

you cannot control the degree of brake force, which is available with a mechanical "handbrake";
if the battery is completely discharged, it is impossible to remove the car from the electric handbrake until the charge is replenished;

It is impossible not to mention, speaking of Auto Hold, that such a solution is more expensive, increasing the price of the car. Including the higher the cost of repairing a failed brake unit.

Precautionary measures

If you intend to move away with active automatic hold (press the gas pedal), you need to depress the pedal carefully, gradually increasing the speed so that the start-off is smooth, without jerks. It is also advisable to turn off this mode when driving downhill, when driving backwards and parking.

If a malfunction is found, or the system does not work properly, you should contact an authorized service center for appropriate diagnostics and repair of the complex electronic unit.

Do not keep a car equipped with this system with the parking brake applied for too long. The block consumes the battery charge, and if it is completely depleted, the car will not be removed from the parking brake just like that.

When service and repair work is carried out, the electronics of the machine must be put into service mode. If this is not done, the brake can be applied during work, which, in turn, will lead to damage to the vehicle and personal injury. All service operations, including the replacement of pads, should be carried out on specially designed equipment.

In some Volkswagen car models (Tiguan, Touareg, Golf, Passat sedan, Passat Variant) an electromechanical parking brake with AUTO HOLD function is standard equipment.

Benefits of using

More safety and comfort is provided by the functional extensions of the electromechanical parking brake: "dynamic start assist", "dynamic emergency braking function" and the "AUTO HOLD" function.
Unintentional rollback is prevented.
Optimum brake engagement point compared to mechanical handbrake.
Saves space inside the passenger compartment, more space in the center console area (eg for cup holders).

Operating principle

The Volkswagen electromechanical parking brake replaces the conventional handbrake with a button in the center console. There is no traditional hand brake lever.

This system is designed in such a way that in the event of a voltage failure in on-board network the parked vehicle continues to be securely supported.

When the parking brake is applied, the warning lamps in the instrument cluster and in the button light up; the sound of the brake actuation indicates that the brake is engaged.

Modes of operation

static mode: vehicle speed below 7 km / h;
dynamic braking: vehicle speed exceeds 7 km / h;

Additional functions

dynamic starting assistant;
dynamic emergency braking function;
AUTO HOLD function.

Dynamic Start Assistant

Provides smooth starting of the car without rolling back when the electromechanical brake is on, even on an uphill.

This function is available if:

the driver's door is closed;
the seat belt is fastened;
the engine is running.

The vehicle must not be held down with the brake pedal (for example, when stopping in front of a traffic light) if the electromechanical parking brake is activated.

As soon as the accelerator pedal is depressed, the parking brake is automatically released and the vehicle starts.

If the driver is not fastened, the parking brake can only be released manually by simultaneously pressing the brake pedal.

Dynamic auto brake function

If the brake pedal fails or is locked, the vehicle can be effectively braked using the dynamic emergency braking function.

Pull and hold the parking brake button and the vehicle will decelerate at approximately 6 m / s (which is approximately 60% of maximum braking).

In this case, an audible warning signal sounds and the brake lights turn on.

The emergency braking function is realized at a vehicle speed of over 7 km / h by raising the hydraulic pressure in brake system... The braking process, if necessary, is supported by the ABS / ESP function. This maintains the stability of the vehicle during braking.

Releasing the button at speeds above 7 km / h or pressing the accelerator pedal deactivates the emergency braking function. After stopping the vehicle, the parking brake must be released as described for parking.

At speeds below 7 km / h, the parking brake operates in standard electromechanical mode.

How the Auto Hold function works

AUTO HOLD function on Volkswagen cars helps the driver when parking the car and when starting off (when moving forward or backward). The AUTO HOLD function includes the following sub-functions:

Stop-and-Go assistant;
Starting assistant;
Automatic activation of the parking brake.

The AUTO HOLD function is an extension of the electromechanical parking brake function.

Conditions for activating the Auto Hold function

the engine is running;
the driver's door is closed;
the driver's seat belt is fastened;
the Auto Hold key is pressed.

The system is triggered by the ABS / ESC hydraulic unit.

After the vehicle is completely stopped by braking, the AUTO HOLD function retains the last brake pressure.

When the driver takes their foot off the brake pedal, the brakes continue to hold the wheels by maintaining the pressure in the braking system.

When the ABS wheel sensors detect the vehicle rolling, the braking pressure is automatically increased until the vehicle comes to a standstill (example of braking on a slope). As soon as the driver presses the accelerator pedal again and, in the case of a manual gearbox, engages the clutch, the AUTO HOLD function releases the brake again.

After three minutes of holding the vehicle, the electromechanical parking brake is applied instead of the hydraulic brakes.

The electromechanical parking brake is automatically activated when the vehicle is stopped under the following conditions:

Auto Hold function activated;
the driver's door is open;
the driver's seat belt is unfastened;
the ignition is off.

For safety, when starting the engine again, it is necessary to reactivate the AUTO HOLD function using the button located to the left of the gear lever. On some models, such as the Golf VII, the Auto Hold function remains automatically activated when the engine is restarted.

To keep the car on a slope, it is necessary to create a high braking pressure in the system. When starting off again, this pressure must first be overcome in order for the vehicle to move. The system only releases the brake when the engine has sufficient power to overcome a roll-off of the vehicle. Carry out a test drive with the customer to demonstrate this unusual vehicle behavior.

Pros:

Relieves the burden on the driver, especially when driving with constant stops, because he no longer needs to press the brake pedal to keep the car in place;
Automatic support when stopping and starting off helps to get under way on an incline; involuntary rolling is prevented;
The AUTO HOLD function provides automatic controlled holding of the car in place, regardless of the reason for which the car stopped;
The parking brake is automatically activated when the driver's door is opened, when the seat belt is unfastened or after the ignition is switched off.

The electronic parking brake is installed on vehicles:

Golf hatchback, Golf Sportsvan, Golf Variant, Sharan, Touareg, Tiguan, Touran, Passat sedan, Passat Variant, Volkswagen CC.