The three regular-service buses covered an impressive 1,400 kilometres in five days. To do this, the three Citaro vehicles pounded the approx. 18.6-kilometre route around the clock, overcoming an altitude difference of over 400 metres on each circuit. The record run was interrupted only for two meticulously monitored and precisely documented refuelling stops each day. In other words, this was a comparison drive under extremely realistic conditions. To make the comparison even more realistic and practice-oriented, all three Citaro vehicles were followed some distance behind by an operating regular-service bus. This included pulling off at all stops, opening and closing of the doors and lowering of the bus by means of kneeling. Lowering the bus to enable easier access is particularly energy-intensive for regular-service buses.
The Citaro Euro VI impresses here with a lower entrance height that significantly reduces the air and energy requirement in the kneeling process.
As high-tech as formula 1.
Another highlight: Research into the principle of energy recovery and use in high-tech Formula 1 cars has been going on for some time. However, whereas these racing cars convert excess braking energy into usable electricity, the Citaro Euro VI does not use the energy-recovery principle. Instead, free electricity generated in overrun mode is stored in dual-layer capacitors (supercaps) and is available the next time for acceleration. This relieves the burden on the alternators and reduces fuel consumption. At the end of the five-day run, these and other clever detailed solutions were to produce substantial savings. However, in addition to optimisation of the various auxiliary units, the main factor in efficient operation waste extremely efficient new BlueEfficiency Power engine, which produces 299 hp in the Citaro Euro VI and transfers it to the rear wheels via a fully automatic ZF Ecolife torque-converter transmission system.
As befits a genuine record attempt, every single detail was meticulously controlled and monitored. All parts critical to fuel consumption were sealed by an officially recognised expert from DEKRA before the start of the run. The tank was also sealed and specially opened for each refuelling operation by the expert. Refuelling was always carried out at the same filling station, and even at the same pump, in order to ensure maximum precision. Even the position of the tyres during refuelling was precisely defined. Colour marking on the ground set out the exact position in every refuelling process: a fine-tuned operation. In addition to the onboard telematics system FleetBoard all three Citaro vehicles were fitted with fuel-consumption measuring devices. The technical systems and refuelling processes were therefore fully monitored and logged at all times.
All’s well that ends well.
After covering 1,365.2 kilometres, the Mercedes-Benz Citaro Euro VI actually exceeded all expectations yet again, comfortably beating its famously economical predecessor once more with a fuel saving of 8.5 percent in the record run. At an annual mileage of 60,000 kilometres per year, this reduces the environmental impact by a hefty 5,700 kg of CO₂ emissions. Not to mention the economic aspect: fuel consumption can be reduced by around 2,700 litres per year. With fuel prices constantly on the rise, this is a considerable factor. The Citaro Euro VI will recoup its high acquisition costs after just four years. Conclusion: with the Mercedes-Benz Citaro, the switch to Euro VI not only significantly reduces fuel consumption and pollutants, but also pays off financially.