Voith Turbo

Engineering firm uses Simcenter Amesim to produce
intelligent transmissions that lead to greener city buses


  • Improve the hydraulic valve behavior of the four-speed automatic transmission
  • Introduce a systematic development process for mechatronic products


  • Use 1D multi-domain system to predict dynamic behavior of systems and subsystems
  • Leverage scope and quality of Simcenter Amesim libraries


  • Reduced testing time and number of prototype iterations
  • Developed improved design for hydraulic valves
  • Shortened time-to-market
  • Enabled continuous improvement to the design and development processes
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The overall testing time was considerably reduced and fewer prototype iterations were necessary.

“ Simcenter Amesim provides us with a powerful and flexible simulation environment for a systematic and detailed analysis of dynamic system behavior. This helps us to continuously improve our design and development process.”

Bernhard Höfig
Mechatronics and Simulation
Voith Turbo

Voith Turbo improves design and reduces testing time of hydraulic valves with the help of Siemens PLM Software solution

Stretching resources

As gas prices continue to be turbulent and environmental concerns grow, fundamental behavioral shifts are taking place. The energy crisis is not only turning consumer preferences to smaller and more fuel efficient vehicles, but it is also engendering a keen awareness of when and how frequently people use their cars.

More and more people are choosing public transportation because it is a cheaper and more environmentally friendly alternative for getting around. According to a recent Public Broadcasting  service (PBS) report, mass transit ridership has increased significantly in nearly all American cities.

In Boston, Massachusetts, subway ridership has grown 9 percent; in Seattle, Washington, the number of commuter rail passengers is up 28 percent; and in San Antonio, Texas, bus ridership has risen by 11 percent.

While transit officials welcome the growing number of commuters, they cannot escape the volatile oil prices and elevated cost of mass transportation service.

voith turbo

Enhancing efficiency and sustainability

According to Voith Turbo, the way to answer many of these concerns is to implement an automatic transmission.

Part of one of the largest family-owned companies in Europe, Voith Turbo is a leading specialist in power transmissions.

Based in Heidenheim, Germany, it has developed a four-speed automatic transmission especially for city buses. Founded in 1867, the company produces state-of-the art hydrodynamic drive, coupling and breaking systems for road, rail, marine and industrial applications.

Voith Turbo’s automatic transmissions for buses – DIWA.3E and DIWA.5 – can be installed in any driveline bus and will enhance fuel economy, passenger comfort, operating efficiency and reliability.

Voith Turbo has delivered more than 150,000 DIWA automatic transmissions to bus customers in Asia, Europe and the United States.

“ Using 1D multi-domain system simulation is particularly valuable since the dynamic behavior of such systems is hard to predict and every single subsystem needs to be taken into account.”
Bernhard Höfig Mechatronics and Simulation Voith Turbo


Producing intelligent transmissions

The DIWA transmission comes with intelligent acceleration-dependent gearshift programs that adapt to topography, vehicle acceleration, axle transmission ratio and load conditions.

This optimizes the shift points and minimizes fuel expenditure. The transmission is further equipped with a hydraulic torsional vibration damper for minimal engine speed after shifting as well as standard automatic neutral shifting for interrupting power transmission between the engine and transmission when the bus is stationary.

Moreover, it is possible to select from four different gearshift programs adapted to operating conditions.

The transmission state is continuously monitored by patented software to prevent transmission overhauls and, interestingly, comprehensive operational data is recorded for later vehicle design optimization as well as maintenance and repair. 

Reducing testing time

Like most automatic transmissions, the DIWA transmission is hydraulically operated and this is where Siemens PLM Software stepped into the picture.

In 2005, Voith Turbo requested a hydraulic valve case study to improve the hydraulic valve behavior in terms of stability and functionality.

The company wanted to analyze its systematic processes and understand the test results.

It was also interested in introducing a systematic development process for mechatronic products as well as parameter variation studies and other enhanced solutions.

“ Simcenter Amesim rapidly proved to be the ideal solution for the design of valves in our automatic gearboxes. It definitely helped to streamline the design and development of our transmission systems, making them readily available for the transportation market.”