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Journalists test anticipatory cruise control

Daimler (Germany) cites up to four percent less fuel consumption through the use of their anticipatory cruise control in the touring coach. During drives with bus and coach journalists at the wheel, the consumption of touring buses with this system even fell by an average of 9,2 %.

JOURNALISTS FROM THE SPECIALIST PRESS FROM ALL OVER Europe tested Predictive Powertrain Control (PPC) on the topographically challenging A6 motorway between Kaiserslautern and Grünstadt. On five days of driving they covered a total of 3120 km. The fuel consumption was precisely recorded using measuring devices. Three Setra Top Class 500 touring coaches were tested in various versions. The three-axle super-high-deck touring coaches were each realistically loaded to a gross vehicle weight of 21,5 t.

PPC will be available from the middle of the year as an option in the Setra flagship Top Class 500 (Photo: Daimler)

According to the company, the Setra Top Class 500 is innately economical. The basis for this is provided by aerodynamics with a Cd value of 0,33 and a matched drive system with the Mercedes-Benz six-cylinder in-line OM 471 (output 350 kW or 375 kW) and the automated eight-speed Mercedes GO 250-8 Power Shift transmission. In this configuration the laden super-high-deck touring coaches measuring nearly 4 m in length achieved an average of 31,7 l/100 km without the use of PPC on the hilly motorway.

With PPC the consumption during the test-drives fell by an average of 9,2 % to 28,7 l/100 km. The range of measured values was, irrespective of the personal driving style and the individual setting of PPC, between 27,1 l/100 km and 30,7 l/100 km. The difference amounted to 5,9 % and in the best case even as much as 11.7 %. The test route selected was, with its hilly topography, geared to the use of PPC. According to the company, in other conditions considerably different measured values are therefore possible.

The driver assistance system is the first anticipatory cruise control in the world for touring coaches to intervene in the transmission control. Developed by Daimler Buses, it will be used for the first time from the middle of 2014 in the new top model series, the Setra Top Class 500. This will be followed at the end of 2014 with the Mercedes-Benz Travego and the Setra Comfort Class 500. The system accesses the topographical data of 100 percent of the motorways, trunk and main roads in Europe. Via GPS, it can at all times detect the current position of the coach and the route ahead with its height profile. On the basis of these data (current speed plus the specified speed, the current vehicle mass plus the data on the engine output, torque, and transmission) the system not only controls the speed: via CAN it also intervenes in the transmission and selects the suitable gear.

PPC will be available from the middle of the year as an option in the Setra flagship Top Class 500 (Photo: Daimler)

The system uses peak engine revs before inclines, shifts down in good time in an anticipatory fashion, reduces power before hilltops and within permitted speed range allows the touring coach to freewheel on downhill gradients with light peak engine revs. In so doing, it also uses the Eco-Roll technology: In cases where this is worthwhile the technology selects the transmission's neutral setting and thus allows the touring coach to freewheel for longer in a consumption-saving manner with any drag losses. With this tactic, the system drives as considerately as an excellent coach driver, according to Daimler. Unlike a driver, it always does so with the utmost attention, round the clock without any loss of stamina and with a perfect knowledge of all the trunk roads in Europe.


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