How much power the wheels really need depends on what you want to get out of your car while driving. The engine is able to develop usable power only in a certain rpm range. In order for the vehicle to still develop sufficient traction when accelerating and climbing, a gearbox is required. The gearbox, which is equipped with various gears, provides a gear ratio suitable for specific conditions.
Power transmission with front wheel drive: 1 - engine, 2 - clutch, 3 - speed gearbox, 4 - input shaft, 5 - drive gear (output shaft), 6 - differential (arrows show the direction of movement). I - 1st gear, II - 2nd gear, III - 3rd gear, IV - 4th gear, V - 5th gear, R - reverse gear, A - main gear, T - speedometer drive.
Power transmission with all-wheel drive: 1 - engine, 2 - clutch, 3 - speed gearbox, 4 - input shaft, 5 - front differential, 6 - front drive gear (output shaft), 7 - hollow shaft, 8 - differential gear, 9 - cardan shaft, 10 - rear drive gear, 11 - rear differential (arrows show the direction of movement). I - 1st gear, II - 2nd gear, III - 3rd gear, IV - 4th gear, V - 5th gear, VI - 6th gear, R - reverse gear, A1 - front final drive, A2 - rear final drive, T - speedometer drive.
Gear ratios for adequate traction
When accelerating on the drive wheels, a lot of torque is needed, while a slowly rotating engine delivers little torque. When the first gear is engaged, the ratio between the engine speed and the speed of the drive wheels increases. On the highway, when fifth gear is engaged, on the contrary, this ratio decreases. Thus, the gearbox matches the engine speed with the speed of the wheels.
Clutch interrupts power flow
In addition, the direct power flow from the engine to the gearbox must be interrupted. This is necessary, for example, when you start, stand at a traffic light with the engine running or intend to change gear.
In vehicles with a manual transmission, the power flow is interrupted by the clutch. In addition, the clutch provides shock-free acceleration, as it equalizes the different speeds of the crankshaft and the gearbox input shaft.
The situation is more complicated in the case of an automatic transmission, especially since Audi installs a small technical miracle in its cars - the Multitronic gearbox. The electronic control device selects the most rational gear, taking into account the operating mode and the intentions of the driver. The speed at which the driver presses the accelerator pedal is used by the control unit to determine whether driving is sporty or economical. The gearshift torque is adjusted taking into account the resistance to movement (uphill or downhill), operation with a trailer, headwind. In the case of the Tiptronic automatic transmission, the gears can also be changed manually. When the driver touches the gear selector, a signal is sent to the control device and the control device immediately gives the gearbox the appropriate command.
Repair of complex automatic transmissions is possible only in specialized workshops.
Purpose of the main gear
The main gear is the last intermediate mechanism by which the torque produced by the engine is transmitted to the wheels. Its task is to reduce the number of revolutions that come from the gearbox, increase the torque and evenly transfer it to the drive wheels.
Visitor comments