General information and security measures

General information

Base brake system

On KIA Sportage cars the standard base double-circuit hydraulic brake system with vacuum strengthening is used. At refusal of any of contours (for example as a result of sealing violation) the second continues to function in a normal mode, providing adequate braking of a vehicle. Forward wheels are equipped with brake mechanisms with ventilated disks, back - drum-type mechanisms. In addition the proportional valve regulator of pressure providing dynamic correction of effort of braking of back wheels according to change of load of a back axis of the car is built in a contour of a drive of back brake mechanisms. The lever parking brake has the mechanical hummock drive connected to brake mechanisms of back wheels of the car.

Scheme of the organization of base brake system of KIA Sportage cars

Pressure of liquid in both contours is created by the main brake cylinder (GTTs) having a tandemny design. Activation of GTTs occurs when squeezing a pedal of a foot brake. As a result of increase of hydraulic pressure in working contours of brake system pistons of wheel cylinders are squeezed out of cylinders, providing pressing of frictional blocks/boots to brake disks/workers to surfaces of drums of wheel assemblies.

The tank with brake liquid is fixed on main the brake cylinder (GTTs) and supplies with a working body all hydraulic a path of brake system.

On petrol models the brake amplifier accumulates a part of the depression created in the inlet pipeline of the engine. On diesel models, in view of lack of such source of depression, the special vacuum pump is used. In case of need the special valve provides connection of the relevant source of depression, providing with that strengthening of the influence developed by a pedal of a foot brake.

Electronic systems of anti-blocking of brakes (ABS) and distribution of brake forces (EBD)

ABS

On the vehicles equipped with base brake system sharp squeezing of a pedal of a foot brake leads to blocking of wheels. Coupling of a protector with a paving and the car is thus broken can go yuzy, losing controllability. The system of anti-blocking of brakes (ABS) prevents premature blocking of wheels, continuously operating speed of their rotation during braking at the expense of modulations of pressure of hydraulic liquid in each of brake mechanisms.

4-channel ABS of the MGH 10 type enters into a complete set of the separate KIA Sportage models with three wheel sensors and the equipped electropump the electronic and hydraulic control unit.

Scheme of the organization of system of anti-blocking of brakes of KIA Sportage cars

Forward wheels are equipped with the individual wheel sensors fixed on assemblies of rotary fists, - gear rings (rotors) of sensors are planted on stupichny assemblies.

Details of installation of wheel ABS sensors

The back ABS sensor traces frequency of rotation of a box of differential in a reducer of not cutting back bridge. The sensor is inserted into a case of a reducer and приболчивается to it, - the rotor fastens on a differential box (see an illustration the Order of dismantling of a reducer of the back bridge).

The principle of functioning of ABS is explained on the scheme. The hydromodulator provides three operating modes of ABS: mode of dumping of pressure, mode of deduction of pressure and delivery mode.

Schematic diagram of functioning of ABS

Principle of functioning of ABS

When ABS is not involved, a food on electromagnetic valves does not move and they remain in the normal provisions, i.e., inlet valves leave opened a contour connecting GTTs with wheel, while final block channels «wheel cylinders - the GTTs tank», preventing thereby pressure dumping.

As soon as ECU receives information from any of wheel sensors about the beginning of blocking corresponding wheels/wheels, it develops command for transition of the hydromodulator in a mode of dumping of pressure, upon the corresponding electromagnetic valves power supply therefore inlet valves are closed moves, interrupting pressure giving from GTTs to wheel cylinders, final, on the contrary, open, providing dumping of working pressure in the corresponding contours.

When pressure in working contours falls to critical value, ECU provides hydromodulator switching in a deduction mode by removal of a food from final valves which come back to normally closed position). Thus pressure dumping in the tank of system stops.

When ECU decides that the risk of blocking of wheels is completely prevented, it provides removal of a food from all valves of the hydromodulator and system comes back to a base delivery mode.

The described cycle repeats with frequency of one hundred times a second to a full stop of the car.

At detection of malfunction in an electric or hydraulic part of a control system the ABS control unit (ECU) of system provides with functioning transition it in emergency operation in which a food from all valves of the hydromodulator acts in film, and in a combination of devices the control lamp of ABS (is activated see. Head Governing bodies and operation receptions). The base hydraulic brake system thus continues to function in a usual mode, providing adequate braking of the car. The driver at movement on a slippery paving should observe extra care.

EBD system

With a view of prevention of risk of loss of control over management as a result of drift at premature blocking of back wheels in brake systems of a base design the special valve regulator regulating pressure in brake mechanisms of back wheels depending on load of a back axis of the car is used. Thus the less loading, the smaller pressure moves on back wheel cylinders. As a result, during sharp braking when the center of gravity of the car is displaced forward, the risk of blocking of back wheels before lobbies comes to naught to naught. The main lack of such scheme is conducting to increase in a brake way appreciable decrease in efficiency of functioning of back brakes.

Let's notice also that the form of ideal curve dependence of pressure in contours of back brakes from pressure in lobbies is defined also by identity of structure of a material of frictional overlays of brake blocks/boots. Thus, to achieve optimum distribution of brake forces mechanically it is not obviously possible in principle.

One more lack of use of valves regulators is lack of possibility of the organization of the notification of the driver about their refusal. As a result, the risk of loss of control over driving at sharp braking considerably increases.

Use in standard systems of anti-blocking of brakes of the electronic and hydraulic control unit suggested an idea developers about possibility of the organization of additional monitoring of the moment of the beginning of blocking of the back wheels, allowing to make controllable dumping of pressure in a back brake contour with the minimum deviation from curve ideal dependence of distribution of brake forces.

The comparative charts illustrating distinction in principles of functioning of the valve regulator and EBD system

Thus the principle of the organization of management of pressure dumping in back brake mechanisms is similar to a principle used in ABS: ECU carried out under control switching of electromagnetic valves of the hydromodulator.

Schematic diagram of functioning of EBD system

Application of EBD system allows in an essential measure to reduce length of a brake way and to reduce the effort necessary for squeezing of a pedal of a foot brake. Besides, the effect of decrease in efficiency of functioning of brakes as a result of a warming up of frictional overlays of blocks of forward wheels at the expense of increase of return of back brake mechanisms is compensated.

One more positive EBD property is possibility of the organization of the prevention of the driver about a system exit out of operation, - the standard control lamp brake systems/raisings of the parking brake (is for this purpose used see. Head Governing bodies and operation receptions).

As when functioning EBD the electric pump of the hydromodulator system functioning, in difference from ABS is not used, does not interrupt even at a critical voltage reduction of the storage battery. The comparative scheme of functioning of ABS and EBD systems is presented in the table.

Violation	System		Control lamp
	ABS	EBD	ABS	EBD
No	Functions	Functions	Vykl	Vykl
Refusal of one of wheel sensors	Does not function	Functions	R	Vykl
Failure of the electropump	Does not function	Functions	R	Vykl
Critical voltage reduction of the battery	Does not function	Functions	R	Vykl
Failure of several sensors, failure of valves, ECU refusal, other refusals	Does not function	Does not function	R	R

Operations procedure at operation of a control lamp of ABS during movement

Security measures

Brake liquid is among highly toxic and chemically aggressive connections and at hit on body panels destroys a paint and varnish covering! The brake dust developed in the course of wear process of brake shoes can contain unhealthy the person asbestos, - at all do not inhale it when cleaning brake mechanisms! Work with brake system demands special purity and exact observance of instructions. In the absence of necessary experience it is expedient to address on HUNDRED.

In the course of wheel rotation moisture under the influence of centrifugal force is dumped from brake disks, but there is a silicone film, products of an istiraniye of rubber, greasing and the other pollution reducing efficiency of braking! After installation of new brake shoes the last should be earned extra, - try to avoid sharp braking the first 200 km of run after replacement performance! The disk brake mechanisms damaged by corrosion when braking create the effect of jolting which is not disappearing over time, - replace disks! Dirt burning to a surface of brake shoes lead to formation of furrows on a surface of brake disks that leads to decrease in efficiency of braking!