The Mercedes Benz Vito is the successful, small sibling of the Sprinter in the Mercedes Benz program. We have driven three diesel versions, all based on the same 2.1-liter (128 cubic inches), four-cylinder engine.
The OM 651 diesel is not only used in the Vito, but also in the Sprinter and in numerous other sedan models of the Stuttgart car company. The engines in the vehicles tested complied with Euro-5 engine specifications, which, with their oxidation catalytic converters, particle filters, and cooled exhaust gas recycling, make them in principle also suitable for Euro-6. The common rail injection provides a maximum pressure of 1800 bar. Seven-hole nozzles inject the fuel divided into up to five portions into the combustion chamber. This provides better control of the pressure increase in the cylinder and makes the engine run more smoothly. Two additional compensation shafts run in opposite directions below the crank case to compensate for undesirable inert forces and to avoid vibrations. This is referred to as “Lanchester compensation.”
Sprockets and chains control the camshafts
Sprockets and a short chain in the engine ensure that the camshaft always opens and closes the correct valves. All four-cylinder versions of the Mercedes Vito have a standard six-speed transmission. The Eco Gear 360 transmission originated with the Sprinter. The gear ratios were specially selected for transporters. The first gear has a short transmission ratio to ease the start, while the sixth gear has a long ratio for low-rpm freeway driving. An automatic torque converter is available as an alternative for the 113 and 116 CDI (surcharge 1854 €, standard in the 122 CDI). However, with only five speeds in the test car, it was therefore no longer state of the art. This affected the fuel consumption.
The engineers have generally designed the entire vehicle with economy in mind. The auxiliary aggregates in the Mercedes Vito can no longer tap into power without restrictions. An electrically controlled vane pump handles the oil supply. It controls its the volume independently, as needed. The same applies to the fuel and water pumps, as well as the generator.
Three Engines from 95 to 163 HP Tested
The Vitro was tested in three configurations. The 110 CDi with 95 HP is the basic version and is delivered in the so-called “Compact” form. The 113 CDI with 136 HP has the attribute “Long.” The stately 116 CDI “Extralong” has an engine with 163 HP. All three of them left the assembly line as a van. The three models hold loads between 183 and 219 cubic feet (5.2 and 6.2 m3). The standard separation wall in the truck is profiled so that long and flat loads can still be pushed another 8 inches (20 cm) under the driver and passenger seats. Six or eight (extra long version) fastening eyelets with a tensile strength of 500 daN are available to secure the load. Additional lashing points are provided on the side wall and roof frame.
The OM 651 engines generally work more quietly and more controlled than their predecessors. This pattern holds for all performance levels. Instead of the growl typical for Mercedes, the engines only generate a subdued hum that is drowned out by rolling or wind noises in many driving situations. Noise level measurements while standing and driving confirmed this impression. This is the result of a generally effective damping , in addition to a smoother-running engine.
95 HP Very Optimistic
Even the smallest test participant has to propel 2.8 tons. It struggles to do that. It takes a lot of gearshifts to keep the 110 CDI going when loaded. The wide-spaced Ecogear transmission does not support sportive driving. The transmission has some rather large rpm jumps and shows a certain reluctance to shifting gears, which certainly does not add to the driving pleasure, either. The basic model could nevertheless score brownie-points regarding fuel consumption. We had assumed that the frequent need to downshift would have a negative effect on fuel consumption. However, the 110 had an average consumption of exactly 33.6 mpg (7 l/100 km) and ranked at the top. It was even below its normal fuel consumption when loaded.
Surely part of this is due to the start-stop automatic transmission (included in the Blue-Efficiency package, at an additional price of 250 €), makes a contribution by turning off the motor at traffic light stops and starting up when the clutch is activated. The system works reliably. We found out by accident that the start-stop function also allows the driver to leave the vehicle for a short time, in contrast to the systems of other manufacturers.
More Power Means More Thirst
All three engines are of equal size, but the more powerful ones help themselves to 0.7 liters diesel more out of the tank. The two stronger engines are very similar. Their fuel consumption only differs in the second digit after the decimal point. Driving performance, however, revealed greater differences. The 110 CDI almost reaches 2000 rpm at 62 mph (100 km/h), an rpm speed that calls for shifting into seventh gear, while the 113 and 116 have longer gear ratios and reach only 1800 rpm–and with sufficient torque to be able to accelerate briskly in the highest gear.
The versions with a stronger engine generally allow for more relaxed driving, due to their greater punch. The 116 CDI, the strongest contender, obviously makes the best impression in that regard. Its powerful thrust only stops at 190 km/h (factory information). It is pleasant to note that better springs and shock absorber bring the driving experience closer to that in a passenger car, even when the vehicle is loaded. The seating position and cockpit design contribute to that, even though some button have labels that are not self-explanatory to Mercedes novices. But this might be considered “whining over nothing.” The surcharge policy falls into the same category. Wheel caps carry a surcharge (97 €) and so do a lockable cubbyhole (22 €), double doors in the rear (from 368 €) and an air-conditioning system (1548 €). On the other hand, there is hardly a competitor who could provide so many functional extras ex factory, e.g. four-wheel drive (3143 €), electric sliding doors (701 € each) or DVD-based GPS (from 2785 €).