Test drive Volvo FH16 and BMW M550d: Newton's law

An interesting meeting in absentia of two exotic car breeds

We are talking about forces - in one case expressing acceleration, and in the other - on the table. An interesting correspondence meeting of two exotic breeds of cars, each in its own way demonstrating the extremism of the six-cylinder philosophy.

The in-line six-cylinders silently balance themselves in a way that no other engine can match for its sophistication. A similar postulate is true for any in-line six-cylinder unit. However, these two belong to a special breed - perhaps because they are the extreme representatives of their species. With its 381 hp. and just three liters of combustion engine displacement, driving the BMW M550d creates an unparalleled image in the automotive fauna and could even be considered a radical expression of downsizing (we don't have any idea how the 4 turbocharger version will work yet). "Maybe" because BMW hasn't ditched eight-cylinder engines in the name of downsizing. The power of the N57S unit, of course, is not in economy - in one of the latest tests of the auto motor und sport M 550d, it noted an average fuel consumption of 11,2 liters. And that's from a machine that weighs "barely" two tons. They may look impressive compared to the rest of the automotive world, but they are nothing compared to the 40-ton train that travels on the roads. Volvo FH16. With an average consumption of only 39 liters of diesel fuel per 100 km. What is this comparison? It's very simple - both the M550d and FH16 take the six-cylinder philosophy to the extreme, and this is a rare occurrence, but only in the family of heavy tractors - whether on-road or off-road.

40 tons is not a problem for this machine. Even on steep sections of road, the FH16 continues to maintain its "cruising" speed of 85 km / h, as long as the bends of the corners allow it to move in a similar way. However, in such cases, the FH16 is rarely used and mainly by companies that need fast transport on steep roads. The real power of this truck is no more and no less than 750 hp. power and torque of 3550 Nm, used as a tug for transporting large and heavy loads such as construction equipment or distillation columns for refineries. In Sweden, where, unlike in Europe, the law allows trains heavier than 40 tons, about 60 tons of cargo, such as logs, is usually transported. It's not that it can't handle the 60 tons in question with almost the same ease as the 40s, according to colleagues from auto motor und sport magazine's truck and bus subsidiary lastauto omnibus.

Maximum torque at 950 rpm

The machine with three turbochargers from BMW manages to achieve a maximum torque of 740 Nm at 2000 rpm. The Volvo FH16 D16 engine cannot even dream of such speed. A 16,1-litre machine with a single cylinder displacement equal to a 2,5-litre beer bottle with another 168 milliliters of bonus, reaches a maximum torque of 3550 Nm at ... 950 rpm. No, there is no mistake, and in fact there is no other way out with a piston diameter of 144mm and a stroke of 165mm. Just before the BMW engine reaches its maximum torque, the Volvo D16 engine reaches its maximum power - in fact, it is available in the range from 1600 to 1800 rpm.

The history of the D16 dates back to 1993, and over the 22 years of its existence, its power has grown steadily. The latest version of the D16K now has two cascade turbochargers in the name of achieving the Euro 6 emission standard. Thanks to them and the increased injection pressure in the pump-injector system to 2400 bar, it manages to deliver the aforementioned torque so early. In the name of better mixing of fuel with air, multiple injections are carried out, and the "exhaust" aftertreatment unit, which includes the DPF filter, catalytic converter and SCR unit, is larger than the entire trunk of a BMW.

Thanks to the stock M550d all-wheel drive system, there is no problem transferring all the power to the road. Even in wet areas, the four-seater is unlikely to get out of hand, and thanks to the M-settings of the xDrive system, some flirting with the back is allowed. The real possibilities of the car can be seen in the rather vivid expression of the limitless speed of the highway, on which most drivers become extras. It really doesn't matter which of the eight gears of the automatic transmission is engaged - over 2000 rpm, when the boost system reaches sufficient pressure (3,0 bar max), the monstrous torque hits you with all its might and the M550d starts shifting transmissions cleanly and with incredible accuracy.

Engine weighing 1325 kg

Volvo FH47 with 16 HP / l can not match the dynamic acceleration of BMW with its 127 hp. / l. However, a heavy machine with different options for the number of drive axles creates a feeling of titanic power, especially when loaded. Every fiber in your body feels like the start of a 62-tonne shift and a new I-Shift DC dual-clutch transmission, the first of its kind on a highway tractor, by the way. For trucks, and especially the FH16, the architecture of the automatic and dual clutch transmissions is different and includes a basic three-speed mechanism with a so-called range/split gear group, providing 12 gears. They are lined up with great precision and with a short hiss of the pneumatic system. All the mass is pushed forward, making you feel the other component of Newton's force equation. It's not acceleration, it's mass. Steep climbs or huge loads - the Volvo FH16 simply inflates its twin turbos, injection, still unattainable for car engines, starts to pour out a lot of diesel fuel (maximum load flow is 105 l / 100 km), and giant pistons flex their muscles. take this huge burden on your shoulders. They have no peace, because sooner or later, when this whole composition has to be stopped, they will have to help the classic braking system. VEB+ (Volvo Engine Break) technology that uses valve control to use compression and exhaust clocks to generate 470kW of braking torque. If necessary, an additional retarder is added to control the weight in the equation.

Text: engineer Georgy Kolev

BMW N57S

The BMW charging system is a joint venture between the Bavarian company and BorgWarner Turbo System and is not called R3S. In practice, this is an upgrade of the R2S turbocharger used by the same company. The difference between the two is that the third, again small, turbocharger is housed in the bypass exhaust duct connecting the small and large turbocharger. With it, the system becomes parallel-serial - since the third turbocharger pre-charges air for the big one. The crankcase is connected by studs for the head - this architecture significantly increases the strength of the engine structure. The crankshaft and connecting rods are also reinforced to withstand the 535d's increased operating pressure from 185 to 200 bar. The fuel injection pressure has also been increased to 2200 bar and a sophisticated water circulation system cools the compressed air.

Volvo D16K

The Volvo D16 engine, which also forms the basis of the Penta family of marine products, is available in 550, 650 and 750 hp power levels. The latest K version replaces the VTG variable geometry turbocharger with two cascade turbochargers. This allows the filling pressure to be increased over a wide range of speeds. Increased power of the intermediate cooler and decreased compression ratio. This reduces the temperature of the combustion process and the emissions of nitrogen oxides. Even the Bosch-modified BMW system for the N57S cannot compete with its 2200 bar and Volvo with its 2400 bar. The dry weight of this giant unit is 1325 kg.

TECHNICAL DATA BMW M 550d

Body

4910-seater sedan, length x width x height 1860 x 1454 x 2968 mm, wheelbase 1970 mm, net weight 2475 kg, total permissible weight XNUMX kg

Independent front and rear suspension, MacPherson strut with double wishbones, rear with transverse and longitudinal struts, coaxial coil springs over telescopic shock absorbers, front and rear anti-roll bars, internally vented disc brakes, front / front 245, rear 50, rear rear 19/275 R 35

Power transmission

Dual gearbox, eight-speed automatic transmission

Engine

In-line six-cylinder diesel engine with three turbochargers and intercoolers, displacement 2993 cm³, power 280 kW (381 hp) at 4000 rpm, maximum torque 740 Nm at 2000 rpm.

Dynamic characteristics

0-100 km / h 4,7 sec

Maximum speed 250 km / h

Average fuel consumption (in AMS test)

diesel 11,2 l / 100 km

VOLVO FH16 SPECIFICATIONS

Body

Volvo Globetrotter XL, full steel cab with steel superstructure, both fully galvanized. Four-piece air suspension. The frame with transverse and longitudinal elements is fastened with bolts and rivets. Front and rear stabilizers. Two-leaf parabolic springs in front, pneumatic with four pillows in the back. Disc brakes with electronic control

Power transmission

4 × 2 or 6 × 4 or 8 × 6, 12-speed dual-clutch transmission or automatic

Engine

In-line six-cylinder diesel engine with twin turbochargers and intercooler, unit injector, 16 cc displacement, 100 kW (551 hp) at 750 rpm, maximum torque 1800 Nm at 3550 rpm

Dynamic characteristics

Maximum speed 250 km / h

Average fuel consumption (in the Lastauto Omnibus test) 39,0 l

diesel / 100 km