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. Last Updated: 07/27/2016

New Volvo Has Viscous Answer to Snow and Ice

Volvo: It's a name that resonates with most Russian motorists. Volvos were the first foreign cars to become popular in the former Soviet Union, and for many Russian drivers they still symbolize the highest quality in car manufacturing.


The Volvo 850 sedan is one of the most popular cars in Moscow today, and only certain off-road vehicles have given it serious competition. But that situation may change with the announcement of Volvo's new model -- the Volvo 850 AWD (All-Wheel-Drive), with a sale price of around $60,000.


Volvo did not expect to produce this type of car, according to Olle Odsell, Volvo's public relations manager, in an interview at the company's factory in G?teborg, Sweden. "But the idea came to us while working on the 850 Estate, and the car was developed in a very short time."


The 850 AWD Estate, or station wagon, is based on the well known Volvo 850. It is powered by a turbocharged, five-cylinder, 2.5-liter engine with four valves per cylinder. Most other basic devices are also taken from the 850 model, though the rear-wheel suspension comes from the Volvo 960.


The main difference between the Volvo 850 and its AWD cousin is that the latter is equipped with systems designed for better control, distributing power among the car's wheels for maximum traction during bad weather or on bad roads.


The key to coordinating power between the rear and front wheels is a propeller shaft that is driven by a transfer gear fitted alongside the gearbox. The shaft is split, so power is not transmitted directly to the rear axle but through a device known as viscous coupling: The ends of the two shafts are fitted with plates and enclosed in a casing filled with silicon fluid.


When cruising on straight, dry road with permanent speed, the front and rear wheels spin at about same speed -- and so do the two sections of the propeller shaft. Only a small proportion of the power goes to the rear wheels.


But when you accelerate, drive around a bend in the road or find yourself on ice, snow or gravel, this equilibrium changes and the front wheels begin to spin faster than the rear ones. As a result, the front section of the propeller shaft spins faster than the rear. The friction in the viscous coupling increases and heats up the silicon fluid, which then gets thicker.


As the front shaft section rotates in the thicker fluid, the rear section is compelled to rotate at the same speed, which means that more power from the engine goes to the rear axle.


It all happens automatically and instantaneously, before you even have time to notice that the front wheels are losing grip. And the poorer the grip, the more power goes to the rear wheels. If the front wheels have no grip at all, almost all the power is transferred to the rear ones.


The Volvo 850 AWD is also equipped to distribute power within the front- and rear-wheel pairs, making it easier for you to start moving from a standstill on slippery roads and to drive at low speeds. If one of the rear wheels starts to spin, the automatic differential lock kicks in, sending power to both. Likewise, an electronic traction control, or TRACS, automatically distributes power between the front wheels, deferring to the one that has the best grip. If you don't want to use TRACS, you can simply press a button to disable it.


In simple terms, what this all means for drivers in Moscow is that driving in the city's treacherous winter is no problem in this car because as soon as you hit bad road conditions, the Volvo handles like a sturdy jeep. The car's four-wheel-drive capability means that none of the wheels is going to get stuck in mud, ice or snow.


The Volvo 850 AWD is expected to be produced only as a station wagon, but one with a luxury interior and many options available. And from the point of view of comfort, driving this car is indeed a great pleasure. From the first moment inside you feel as if this car was made for you -- highlights include leather seats electronically adjusted through six directions and with memory for three positions, a hardwood dashboard, a leather steering wheel, a high armrest with cup holder and air-conditioning.


The rear seats are equipped with a special children's seat that can be transferred very quickly and simply from the armrest located in the middle of the seats. And one option is particularly important for Moscow drivers: The rear luggage space can be covered by a special leather blind, to keep prying eyes away from the belongings you store there.


As for road performance, in general the Volvo 850 AWD drives well. It starts and accelerates well, allowing you, for example, to speed up from 90 kilometers per hour to 120 kilometers per hour in fifth gear. But since the 850 isn't a brand-new model, and its on-road "skills" are well known in many countries, its performance in difficult road conditions is what is interesting to drivers in Russia.


In an attempt to replicate our trying conditions, Volvo chose a small forest glade to give its new car an off-road run. The test drive took place amid hard rain, but the car performed very well. At home, I drive a diesel-powered Mitsubishi Pajero, and at first I tried to drive the Volvo using same skills. That doesn't work on the 850, with its gasoline engine. Just a little pressure to the accelerating pedal starts the car moving, when the tachometer hits 2.0 rpm. In second gear, giving a little more power to the engine (to 2.2 rpm) sends the 850 running easily through mud, even when it covers two-thirds of the wheels.


So even though the 850 AWD wasn't produced as an off-road vehicle, it certainly does the job. It is much more versatile than most cars used on regular roads and although I wouldn't want to drive it at an off-road rally, it is certainly powerful enough for small forest roads and the Russian winter.