Hyundai Solaris cars with a 1.4 or 1.6 l engine are equipped with a four-speed automatic transmission mod. A4CF1.
The automatic transmission is arranged according to the traditional planetary scheme with braking by friction and is connected to the crankshaft of the engine through a torque converter.
The electronic automatic transmission control system constantly monitors the speed of the car and the engine load, eliminates driver errors, preventing him from turning on a higher gear at low speed to avoid overloading the engine, or downshifting at too high speed, which eliminates the possibility of exceeding the maximum permissible engine crankshaft speed.
When the speed of the car decreases, the gears automatically switch to lower ones without the driver"s participation.
When the car stops completely, the I gear is automatically switched on.
The automatic transmission consists of a torque converter, a pump, a planetary gearbox, multi-disc clutches, multi-disc brakes and a valve block.
The torque converter performs the functions of a clutch and serves for a smooth connection of the engine and the gearbox mechanism, increasing the torque when the car starts moving.
The body of the torque converter is connected to the crankshaft of the engine through the drive disc and constantly rotates when the engine is running.
The internal cavity of the torque converter is filled with working fluid for automatic transmissions.
The engine rotates the torque converter and drives the pump wheel, which creates working fluid flows in the direction of the turbine wheel. The latter begins to rotate due to the working fluid flows created by the pump wheel.
With a large difference in the rotational speeds of the turbine and pump wheels, the reactor changes the direction of fluid flow, increasing the torque. As the speed difference decreases, it becomes unnecessary and is therefore installed on the overrunning clutch.
A pump located in front of the gearbox crankcase creates pressure and supplies working fluid to all systems in the gearbox.
The planetary gearbox of the system is a gear train with external and internal gears, which provides various ways of connecting its elements to obtain different gear ratios.
The principle of operation of multi-disc clutches and disc brakes is very similar, the difference is that the multi-disc clutch connects the transmission links to each other, and the disc brake connects to the gearbox housing.
The working fluid supplied to the coupling drives the piston, and the friction discs are compressed. The links blocked by the coupling begin to rotate in one piece.
When the disc brakes are switched off, the working fluid ceases to be supplied to the clutch and the piston returns to its original position under the action of the return spring.
The design feature of the multi-disc clutch is that it is in constant rotation and under the action of centrifugal force acting on the working fluid, pressure is created that does not allow the clutch to be unlocked.
Additionally, a ball valve is installed in the coupling. It is located as close as possible to the edge from the center of the coupling.
When the pressure of the working fluid in the chamber of the multi-disc coupling increases, the ball valve closes the drain hole, and when the pressure in the chamber decreases, the ball valve opens the drain hole under the action of centrifugal force and the coupling unlocks.
The automatic transmission control drive is a cable drive, designed according to the same principle as the manual transmission control drive, but differs from it in the number and design of parts.
The automatic transmission selector is installed in the same place on the floor tunnel as the manual transmission control lever and is connected to the gearbox control unit by a cable.
The differential of the automatic transmission is completely similar in design to the differential of the manual transmission.