The way in which the engine develops power and torque over the speed requires a combination of mandatory and manual transmission clutch or converter and tiered / variable automatic transmission. Captured as a combination of the advantages of the automated manual gearbox and the market. Are necessary in any case a translation and a replaceable traction in the drive, the engine is working but only from a speed of 500-800 1/min and is at best as a diesel engine appreciable torque starting from 1300 1/min, the gasoline engine more later. If he demands too much torque when starting, it is called "stalling".

Switching is also becoming increasingly important for CO2 emissions

Conversely, too much suffering in the clutch to start moving. In addition to the driver / s can change (in) or an automatic control the transmission ratio to the drive wheels so that the motor either with the most favorable efficiency, high torque or high performance. It must of course also the emissions of the engine and the installation space, the Schalt-/Geräuschkomfort and the cost of the transmission are considered.

There is almost nothing about direct-shift gearbox.

In the stepped gears different gear combinations to be connected in the power flow. To do this in all gears except the planetary gears and such will be briefly interrupted the flow of power with a double clutch. Except in direct response to all graded transmission are also referred to as a torque converter. Continuously variable transmissions allow a continuous, automatic adjustment to motor traction. The latest craze are dual-clutch Direct Shift Gearbox or the intelligent, very fast and almost without a scarf work truck.

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