In some trim levels of the car, a four-speed automatic transmission of the DPO model is installed, which provides the choice of the optimal gearshift mode for almost any driving styles and road conditions

Automatic transmission of Renault Duster carRenault Duster automatic transmission

The automatic transmission is arranged according to the traditional planetary scheme with braking by clutches 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 gears without the driver's participation.

At the moment of a complete stop of the car, 1 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.

Renault Duster automatic transmission

The torque converter performs the functions of a clutch and serves to smoothly connect the engine to the gearbox mechanism and increase 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 turbine wheel 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 mounted in front of the gearbox crankcase creates pressure and supplies working fluid to all systems in the gearbox.

Renault Duster automatic transmission

The planetary gear is a gear train with external and internal gears, which provides various ways of connecting its elements to obtain different gear ratios.

Renault Duster automatic transmission

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 as one.

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.

Renault Duster automatic transmission

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 cable-operated, 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.

There are two sealing holes for the output shafts in the differential housing, which allows you to dismantle the gearbox without draining the working fluid.

Disassembly of the automatic transmission is discussed in the article - "Disassembly of the automatic transmission DPO"

Repair of the hydraulic unit of the automatic transmission is considered in the article - "The principle of operation and repair of the hydraulic unit of the automatic transmission DPO (AL4)"