DuaLogic Transmission?  

     The DuaLogic transmission is used in some Fiat cars to deliver better performance combined with fuel economy. The DuaLogic gearbox combines the features of an automatic gearbox with those of a manual gearbox, and uses an onboard computer to aid performance and fuel savings. The DuaLogic transmission ensures the gearbox is always in the most effective gear for the driving conditions.
     The DuaLogic gearbox uses an electrohydraulic servo to automate the clutch and gear lever. In semi-automatic mode, the driver uses a lever rather than a clutch pedal to change gears up or down. The DuaLogic contains a computer, which collects data from the gearbox, the clutch, braking system and the engine. This allows the DuaLogic to coordinate the actions of the gearbox with those of the rest of the car, for example, automatically increasing engine speed when you downshift. In automatic, the DuaLogic can also recognize road gradient and can change the gear shift point to give the best combination of performance and fuel economy.
     The DuaLogic has a choice of operating modes for the driver to chose from. In automatic mode, the DuaLogic selects the gears and operates the clutch. In automatic, the DuaLogic's electronic management system will change gears at the time of maximum engine performance to achieve maximum acceleration. In manual mode, the driver selects the gears and operates the clutch, as in a normal manual transmission. In semi-automatic mode, the DuaLogic operates the gearbox, but the driver can downshift when she feels the need -- such as to take a corner at speed.

How a clutch works - internals of transmission and clutch assembly 

Mercedes Benz 7G Tronic

What Is A Torque Converter? 

         If you've read about manual transmissions, you know that an engine is connected to a transmission by way of a clutch. Without this connection, a car would not be able to come to a complete stop without killing the engine. But cars with an aut­omatic transmission have no clutch that disconnects the transmission from the engine. Instead, they use an amazing device called a torque converter. It may not look like much, but there are some very interesting things going on inside.

Just like manual transmission cars, cars with automatic transmissions need a way to let the engine turn while the wheels and gears in the transmission come to a stop. Manual transmission cars use a clutch, which completely disconnects the engine from the transmission. Automatic transmission cars use a torque converter.
A torque converter is a type of fluid coupling, which allows the engine to spin somewhat independently of the transmission. If the engine is turning slowly, such as when the car is idling at a stoplight, the amount of torque passed through the torque converter is very small, so keeping the car still requires only a light pressure on the brake pedal.
If you were to step on the gas pedal while the car is stopped, you would have to press harder on the brake to keep the car from moving. This is because when you step on the gas, the engine speeds up and pumps more fluid into the torque converter, causing more torque to be transmitted to the wheels.

there are four components inside the very strong housing of the torque converter:
  • Pump
  • Turbine
  • Stator
  • Transmission fluid

In addition to the very important job of allowing your car come to a complete stop without stalling the engine, the torque converter actually gives your car more torque when you accelerate out of a stop. Modern torque converters can multiply the torque of the engine by two to three times. This effect only happens when the engine is turning much faster than the transmission.
At higher speeds, the transmission catches up to the engine, eventually moving at almost the same speed. Ideally, though, the transmission would move at exactly the same speed as the engine, because this difference in speed wastes power. This is part of the reason why cars with automatic transmissions get worse gas mileage than cars with manual transmissions.
To counter this effect, some cars have a torque converter with a lockup clutch. When the two halves of the torque converter get up to speed, this clutch locks them together, eliminating the slippage and improving efficiency.

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