Automatic Transmissions (AT)
Modern vehicle transmissions satisfy exacting demands on driving dynamics and ride comfort, and they reduce fuel consumption and emissions. We achieve these ambitious goals with our unique synthesis programs for new, optimized transmission structures, a perfected development process, efficient methods, the systematic use of simulation tools and a broad range of measuring and testing equipment.• Algorithm and Software Development.
In developing software and algorithms for transmission control systems, we turn design and requirements specifications into production-ready reality. Our software developers benefit from broad expertise in engineering open and closed-loop control strategies at prototype and production level for all modern automatic transmissions, such as dual-clutch transmissions (wet and dry), automated manual transmissions and automatic planetary transmissions with converter. Software development focuses on controlling the shifting process in automatic transmissions, on developing diagnostic and safety strategies as well as additional functions in hybrid powertrains, such as stop/start, coasting and the activation of additional torque. In addition to manual coding, code for the algorithms is extensively generated automatically on the basis of software development systems, such as MATLAB / Simulink. Commercially available as well as custom-built tools and development environments are used for quickly implementing and integrating prototype software• Computation and Simulation.
We use innovative simulation methods to optimize the transmission’s acoustic and vibrational behavior (NVH). Against the backdrop of growing demands users are making on comfort, vibration dynamics and acoustic behavior of vehicle powertrains play a crucial part in the development process. This is why our development engineers optimize the layout of transmissions in terms of acoustics and dynamics at an early concept and development stage. They do this using numeric computation and simulation processes, such as the finite-element method (FEM) and multi-body simulation (MBS).• Mechanical and Software Testing Mechanical System Testing
We measure transmission characteristics from the first load-collective measurement to the start of production on the basis of specification requirements and customer-specific test criteria. These include function and endurance tests on components, transmission systems and entire powertrains, validating resistance to misuse and evaluating acoustics. We conduct testing on our own test benches that are equipped with state-of-the-art measurement systems. Validation drives carried out under extreme conditions (summer, winter, altitude) complement the test series. After analyzing results, we take them as the basis for defining optimization measures to save costs and improve efficiency.Software Testing
We test the transmission’s control and diagnostic software at various stages of the development process. This is where we work with “White-Box-Tests” on the basis of modeled structures as well as with “Black-Box-Tests” for testing algorithms in control units. Wherever possible, we substitute or supplement expensive test drives with simulation – such as HiL simulation.• Transmission and Control Calibration
Properly calibrated, transmission shift programs optimize drivability and ride comfort. A transmission’s shift strategy and shift quality go a long way toward influencing vehicle drivability and ride comfort. We optimize gearshift processes by calibrating and precision-adjusting the electronic transmission control system on the basis of generally acknowledged criteria or criteria arranged with the client.
The way to optimizing shift strategy:
- Designing shift points
- Calibrating situation-specific driving modes: consumption-optimized, sporty, hybrid (electric), hill-climbing
- Calibrating all transmission and special-purpose functions relating to driving strategy, such as driver-type identification.
- The way to optimizing shift quality:
- Calibrating shifting-process control
- Calibrating gear engagement and driving off
- Calibrating converter lockup clutch
- Calibrating specific operating modes: cold, hot, altitude
- The way to validating functions:
- Measuring driving properties with boundary components (tolerance range)
- Calibrating diagnostic functions and / or limits
- Calibrating emergency driving properties in the event of a malfunction.