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Ето това имах на предвид, че Халдекса не разпределя постоянно 50:50, а по-скоро 90:10 и при нормални условия колата си е като с предно предаване. Със всичките недостатъци на това.
А и когато на предните гуми им се събере много натоварване, от по-голямата маса, завой и т.н. те много по-лесно губят сцепление. А веднъж загубено сцеплението трудно се връща и на висока цена.
А когато върт. момент се разпределя постоянно към всички колела, тогава претоварването на предницата е много по-малко, и колата е по-стабилна.
Ето и обещаната информация, която успях да събера, преди да ми омръзне:
For the 1999 model year VW has upgraded its AWD system from the viscous coupling based system to a computer controlled clutch developed by the Swedish company Haldex. The advantages include added simplicity since the extra clutch needed for braking can now be eliminated. Also, more precise control of the torque splits and a greater transfer ratio is possible. Derivatives of the AWD fourth generation Golf, (now renamed the "Golf 4Motion") such as the Audi TT and the A3 quattro will use this system. Note that this is still a part time, automatically enganging four wheel drive system. The quattro name, which used to have special significance is now being diluted by marketing expediency. Considerable confusion has arisen from the naming corruption by the two companies.
For the part time VC systems this ratio is usually quoted as 95% front, 5% rear. Some have argued that the 5% constant rear drive would qualify it to be considered a full time system. Regardless of the merits of this argument, the fact remains that the main reason why there is a dribble of power going to the rear wheels is because a little "slip" is deliberately engineered into the driveline to keep the VC tight, so that when the front wheels spin there is little or no lag before the rear wheels start driving. The VC in this implementation always thinks that the front is slipping slightly relative to the rear even if all four wheels are running at exactly the same speed. Slightly different final drive ratios are used to achieve this.
The Quattro system, which is also used in the V6 Golf and Bora 4Motion, uses a combination of dynamic signals to determine the distribution of torque. At complete rest, as it were, using a feathered throttle on a straight, level road, 95 per cent of the torque is delivered to the front wheels. At the opposite extreme the whole 100 per cent can be sent aft to power only the back axle. In reality, the power distribution is always somewhere in between the two extremes, moving seamlessly and proportionately back and forth according to the grip of the wheels. As soon as the angle of rotation between the front and rear drive shafts changes by more than 45 degrees, the system kicks in to redistribute the torque. In that time the offending wheel(s) has rotated just 25cm at the circumference of the tyre
if slip occurs at the front wheels so that traction is no longer available in full, the torque distribution system takes effect and redirects an increasing amount of engine torque to the rear axle in an accurately controlled process.
Note that this is still a part time, automatically enganging four wheel drive system. The quattro name, which used to have special significance is now being diluted by marketing expediency. Considerable confusion has arisen from the naming corruption by the two companies.
For 2001, Volvo has taken the mechanical viscous-clutch system from the previous XC and shortened its response time when slippage is detected. Under ideal traction conditions, this system sends most of the engine's power to the front wheels — it's a 95 percent front, 5 percent rear split. When traction conditions change, up to 95 percent of the power can be redirected to the rear axle. Further, the viscous clutch automatically shifts power to the rear when the Cross Country is put in reverse. As we drove our test vehicle, these transfers occurred imperceptibly.
This change from a purely mechanical viscous coupling setup to an electronically controlled wet multi-clutch system is significant for two reasons. First, electronic control allows for infinite tailoring and programming possibilities to suit a variety of applications. Second, the new Haldex (a Swedish automotive supplier that also makes the AWD system in the Audi TT) AWD system can be mated to Volvo's Dynamic Stability and Traction Control System (DSTC). DSTC combines skid and traction control to keep the car stable in adverse driving conditions, and it will be available on the S60 AWD starting at the end of 2001.
the S60's AWD automatically senses wheel slippage and instantaneously transfers power from the front wheels to all four wheels until both front and rear axles are rotating at the same speed. When the system senses that the front and rear wheels are rotating at the same speed, power flows only to the front wheels for normal driving.
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Re: quattro [re: Caмo Дизeл]
