Under the Skin: The Different Ways Cars Can Be Equipped Car News

The gearbox is one of the most tactile parts of driving and one of the driver’s closest connection to the car. And as they have become more complex, with the emergence of a greater variety of sophisticated technologies, opinions have also become more focused. If internet chatting is anything to do, the favorite among enthusiasts is still the good old-fashioned textbook.

A look inside the different types of gearboxes can give an idea of ​​the reason. Manual transmissions, straight cut manual transmissions, automated manual transmissions (AMTs), dual clutch transmissions (DCTs) and motorsport sequential transmissions all share a single meshing gear train. constant. In its simplest form, the gears on one shaft (the main shaft) are in constant mesh with a second set of gears on an intermediate shaft, hence the name.

The intermediate shaft is cut from a single piece of steel and each pair of links gives a different ratio. When the driver selects a gear, a main shaft gear is locked into it by a solid steel dog clutch and torque is transmitted through the countershaft to the transmission. The synchronizers between the dogs and the gears prevent cracking.

In an H-shaped manual gearbox, the gearshift is connected directly to the selector mechanism, so that the driver has full control over the timing of the gear change.

An AMT gearbox is a box in which the manual selector is replaced by an electric or electro-hydraulic actuator. They are often seen as slow (although they often aren’t in reality) and have largely been replaced by faster, smoother DCTs.

A straight cut gearbox is one in which the teeth of the gear are cut directly on each toothed wheel, while in a standard gearbox they are cut at an angle (helical). Helical gears are quiet but absorb (lose) more torque from the motor. Straight cut gearboxes are stronger and more efficient but very noisy and normally only used in competition cars. Straight-cut claw boxes go one step further, removing synchronizers between the claw clutches so that gear changes can be made faster and without a clutch. Both are more tactile versions of the manual, but a dog box requires skillful handling.

A motorsport sequential gearbox is a straight cut dog box with a rotary sequential gear selection mechanism. The design is quite different from the others, and instead of an H-shaped gearshift, the shifter is pulled forward or backward to upshift or downshift. Alternatively, they can move via actuators and paddles.

A sequential gearbox can also be set to “flat shift” without lifting the accelerator or using the clutch. When the driver puts pressure on the gear lever, a signal is sent to the engine control unit, which turns off the ignition and fuel injection for a few milliseconds, unloading the torque from the gears and allowing the gear to change. speed to continue. Such “boxes are loud, brutal and thrilling, but are not an option for road cars.

DCTs have two automated clutches each transmitting half the forward speed, allowing gear changes without noticeable interruption in torque on most upshifts, with one clutch closing and the other opening exactly. the same time.