In preparation of the market launch of the new topography-dependent gear-shifting program SensoTop, extensive continuous field tests were carried out and evaluated. The choice of test applications covered a wide spectrum of topographical and traffic conditions. The savings potentials of SensoTop were demonstratively proven both in cities with flat topographies and in demanding application profiles.
Taking up approximately 30 to 40 percent, fuel consumption constitutes a significant share of the operating cost of citybuses. Rising oil and consequently higher diesel prices sharpen the focus of transport operators on consumption-optimized vehicle technology more than ever. Moreover, an increase in fuel efficiency also means active protection of the environment: lower diesel consumption goes hand in hand with optimized pollution control and lower emissions of the greenhouse gas CO2.
With the DIWA automatic transmission, Voith Turbo is making a significant contribution towards economical driveline concepts. The newly developed gear-shifting program SensoTop utilizes potentials that cannot be unlocked by other gear-shifting strategies. SensoTop builds on three complementary dimensions: acceleration-dependent shifting point calculation, the evaluation of driving dynamics and precise topography information from the new, integrated inclination sensor. The combination of these factors makes sure that the system always finds the optimum gear-shifting speed for absolutely any topography and vehicle load situation. By moving the gear-shifting points into the lower speed range, SensoTop also contributes towards the reduction of noise emissions.
The reliable proof of the consumption advantages of SensoTop under real operating conditions was an important building block of the introduction process. In cooperation with leading OEMs, the Voith experts selected a field test program that covered a broad spectrum of topographical and traffic situations. Another challenge was to confirm the consistency of fuel savings across several months.
Among the cities selected for proving the SensoTop consumption advantages in applications with flat topography were Munich and Berlin, where continuous field tests were carried out. In both cities, SensoTop competed against the conventional fuel-efficient serial gear-shifting program “Economy Flat”. During such flat applications with few upward or downward gradients, gear-shifting speeds are reduced to the technically possible minimum. The result of approximately two percent less fuel consumption impressively confirms the SensoTop savings potential also in cities with easy topographies.
In contrast, field test applications in cities such as Zurich, Brescia or Würzburg are characterized by demanding, hilly topographies. On upward gradients, SensoTop automatically had to provide the required power, to instantly select optimum gear-shifting curves and to prevent gear hunting. The continuous evaluation of the DIWA operating data has shown that the full-load and kick-down shares of the field test vehicles were significantly reduced after activation of SensoTop. The field test results are impressive: in Würzburg, the SensoTop consumption advantage was in the region of three percent, in Zurich, consumption was reduced by up to five percent, and in Brescia in Italy, the field test vehicles needed up to seven percent less fuel than identical vehicles with the conventional serial gear-shifting program.
In field tests in cities with mixed topographical conditions, the Voith team also came up with positive results: in Heidenheim, four percent lower fuel savings could be proven on average. In Newcastle, Stagecoach vehicles with SensoTop consumed five percent less diesel.
The positive conclusion from the continuous field tests will now be followed by the market introduction. The topography-dependent gear-shifting program SensoTop creates added value for vehicle manufacturers and operators – and thus also more value for our environment.
Voith Turbo (voithturbo.com), the specialist for hydrodynamic drive, coupling and braking systems for road, rail and industrial applications, as well as for ship propulsion systems, is a Group Division of Voith AG.
Voith (voith.com) is setting the standard in the paper, energy, mobility, and service markets. Established on January 1, 1867, Voith is now one of the largest family-owned businesses in Europe, with 43 000 employees, 4.9 billion euro in sales, and over 290 locations worldwide. Voith is an official partner of the initiative "Germany – Land of Ideas".