THREE SPEED, ZERO ELECTRONICS – The cars are more and more technological, but a few points “fixed” were: the pedals, steering wheel and the gear exchange . Those Automatic , for decades maintained the known positions P (Park, parking), D (Drive or guide) and R (Reverse, which is about to reverse). When talking of driving pleasure, comfort and efficiency in this field we have been made leaps and bounds, even when changing the traditional torque converter. We have had confirmation through a day at the wheel of new and old cars, trying all kinds of transmissions of this type produced in time by German ZF : a multinational company which is celebrating 100 years and 50 since the launch of its first automatic transmission, the 3HP 1965. As the name implies, it is a unit in three reports, completely free of electronics, in which gear selection took place at different pressures in a hydraulic circuit and the predetermined engine speed.
THE FIRST WITH CHIP – The first major developments came in 1982 with the transmission 4HP : by modern standards the shift times are measured in “geological time” (1.5 seconds as the 3HP), but the real news is not the march but the arrival of additional electronics. This allows a control unit to decide in a more refined when passing ratio, based on the engine load, the number of revolutions other than inclination of the road. In addition, the driver can choose between several ways of changing (to enhance comfort or performance). “Our” Audi 200 ( photo above ), it provides a wheel on the tunnel which activates the program “Sport”, with which it passes to the next report 1000 rpm the next minute. Today the obvious feeling of dragging; kicking the engine speed to a minimum “gas tap” leads to smile, but at the time few machines were better. This is because all the power from the engine to the gearbox passes solely through the oil put into movement inside the torque converter (formed by two “paddle wheels”, one integral with the gearbox and the other with the motor shaft): only in fourth gear (the last) a clutch tightening bypassing the converter and allowing the couple to get to the gears of 4HP directly.
mounting him RS6 LA – spend just eight years and, in 1990 , the ZF unveils its 5HP ( photo above ), characterized by a something more and more sophisticated electronics: the change takes place according to the driving style of the driver and can be selected manually, so that is also used on sports as the first Porsche Boxster. Sull ‘ Audi RS6 2002 we are driving this is done not only by the lever but also by two small buttons behind the steering wheel spokes. The 4.2 twin-turbo still attracts with generous boost of 450 HP and for the pounding sound typical of V8. All the more reason, then, “out of place” slow (by today’s standards) gear: a split second to pass ratio. On the other hand, from 5HP on, the automatic transmissions of ZF are all maintenance-free (especially the one on oil, which in the past was changed after a few tens of thousands of kilometers), and introduces the function of “double”: a short acceleration of the engine during the transition to a lower gear that makes the operation smoother.
THE FIRST MODERN – Nell’automatico 6HP 2001 is the internal structure revolutionized (switching to a so-called model Lepellettier, characterized by planetary gears): in spite of the gear, the gear is more compact and lighter than 13 kg (15% ). ZF also declares a 7% improvement in fuel consumption but really we do not we take care of, when with the paddles behind the wheel climb two reports to “our” BMW Alpina B3 GT3 of 2012 ( photo above ): a “monster” in a limited edition based on the 3 Series Coupé and the older generation driven by a 409 hp 3.0 twin turbo well. With this change we enter the modern era and, with his 4-5 tenths of a second to go from one relationship to another, even on a sports car so there is a credible alternative to the manual, and even today does not disappoint (excluding the shutter speed: the torque converter clutch is closed only from the second gear). Not surprisingly, the 6HP is still produced, although only for the Chinese market.
speed it up? HAS NO SENSE – The heir arrives in 2009 and has the popular 8HP ( photo above ): As the name, it is an eight-speed automatic, which is still used on many Audi, BMW, Jaguar, Land Rover and Maserati; and it is on a Quattroporte that diesel back to make your acquaintance. The test in the hills German is a pleasant confirmation: departures are sweet, but already below 15 km / h on the clutch torque converter bolts to avoid annoying “slips” when you press the right pedal. Sport in changing from one gear to another in just two tenths of a second (twice in normal mode): a time, they explain the technicians would not make sense to reduce because the man can not perceive the difference below this threshold . The difficulties now are other, all concerning sizing “up” the electronics: the shift points are set by ZF but they are different from market to market (Asia, Europe, the US and the rest of the world) and are decided according to the motorists’ driving styles of the place and approval cycles. In addition to this, manufacturers may also require that the gearbox has a different “character”, into perceiving more or less change gear (a matter of sensations for the driver, since the shifting speed remains unchanged).
NINE SPEED FOR “SMALL” – The 8HP continues to be updated: in 2014 gets a chance to match it to the Stop & amp; Start (some models that the mountain state average consumption lower than those with manual transmission) and a few months ago was presented the version for hybrid cars, with an electric motor in place of the torque converter. But the 8HP has its limits: it can only be used on a car with a longitudinal engine. For this reason, in the 2013 comes the 9HP , a change much more compact designed to engines arranged crosswise. The unit is used for example by Land Rover for its Evoque, from Fiat for the 500X and the Cherokee and Jeep Renegade (the Fiat-Chrysler it builds its own in the USA, under license). The “big brother” 8HP preserves the sweetness and rapid gear shifts. For the first time the electronics, however, was developed internally by ZF: wanting to nitpick, perhaps for this reason its development seemed to us a bit ‘sour. On the Renegade ( photo above ) that we drove, as on other cars with the same gear as we try, not always the command of climbing is accepted immediately.
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