In a European media test event, the fuel consumption of Daimler’s new TopClass 500 with Predictive Powertrain Control (PPC) (earlier post) fell by an average of 9.2%. Daimler has been citing fuel consumption improvements of up to 4% for the anticipatory cruise control technology.
More than two dozen journalists from the specialist press tested PPC intensively on the topographically challenging A6 motorway between Kaiserslautern and Grünstadt. On five days of driving they covered a total of 3,120 km (1,939 miles). The fuel consumption was precisely recorded using measuring devices. Three new Setra TopClass 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.
The new Setra TopClass 500 is already economical. The basis for this is provided by the aerodynamics with an extremely favorable Cd value of 0.33 and an optimally matched drive system with the Mercedes-Benz six-cylinder in-line OM 471 (output 350 kW/476 hp or 375 kW/510 hp) and the fully automated eight-speed Mercedes GO 250-8 PowerShift transmission.
In this configuration the laden super-high-deck touring coaches measuring nearly four meters in length achieved an average of 31.7 liters/100 km (7.4 mpg US) without the use of PPC on the hilly motorway.
With Predictive Powertrain Control (PPC) the consumption during the test drives fell by an average of 9.2% to 28.7 liters/100 km (8.2 mpg US). The range of measured values was, irrespective of the personal driving style and the individual setting of PPC, between 27.1 and 30.7 liters/100 km (8.7 and 7.7 mpg US). The difference in favor of PPC 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. In other conditions considerably different measured values are therefore possible.
The Predictive Powertrain Control (PPC) 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 the year in the new top model series, the Setra TopClass 500. This will be followed at the end of 2014 by the Mercedes-Benz Travego and the Setra ComfortClass 500. PPC accesses the topographical data of virtually 100 percent of the motorways, trunk and main roads in Europe. Via GPS PPC 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, the current speed plus the specified speed, the current vehicle mass plus the data on the engine output, torque and transmission PPC not only controls the speed; it also intervenes in the transmission and selects the suitable gear.
PPC 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 PPC also uses the EcoRoll 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.