Bits and bytes now play a critical role in the product qualities of vehicles and their components—a trend which is set to increase further in the future. That is why ZF Friedrichshafen AG utilized its extensive electronics expertise with its new nine-speed automatic transmission (9HP) in order to develop and produce the sophisticated control unit entirely in-house for the first time.
ZF sees electronics and software as key factors in meeting vehicle efficiency targets and reducing CO₂ emissions. With the flexible electronic control unit for the 9HP, the technology company is drawing on its bundled expertise in the field of hardware and software development built up over many years: For the very first time, ZF engineers implemented the transmission electronics entirely in-house. The benefits are numerous—both for ZF and for its customers.
The software heart of the electronic control unit is the shift sequence control system, which contains all clutch controls, adaptive functions and transmission protective functions. At the same time, the driving strategy ensures that the optimum gear is selected in every driving situation unbeknownst to the driver. Thus the electronic control unit enables the characteristics of the 9HP to be influenced—by the automotive manufacturer or the end customer. For instance, shift points and shift dynamics can be varied: A configuration consistently optimized for fuel consumption is just as much an option as comfort-oriented or sporty and dynamic gear changes. ZF has also managed to considerably reduce internal transmission drag losses by transferring mechanical functions to the control software: This was one of the prerequisites for being able to replace the mechanical multidisk clutches with hydraulically-operated constant-mesh elements. These elements are not only highly efficient, but also contribute to the 9HP's space-saving design. Consequently, the electronic control unit helps reduce passenger car fuel consumption by up to 16 percent with ZF's new 9HP.
The electronic control unit's current computing performance can be increased by 30 percent when needed—and as a result, the 9HP will also be equipped for even more comprehensive software functions in the future.
In the right place
Due to cost-effectiveness and installation space optimization, ZF engineers did not design the 9HP's electronic control unit hardware as part of a fully integrated mechatronics module with all sensors and actuators. Instead, it is installed separately from the now significantly smaller hydraulic control unit, namely on the upper side of the transmission housing.
The hardware and software of the electronic control unit for the 9HP was developed jointly in Auerbach and Friedrichshafen, Germany. The electronic control unit has been manufactured at ZF at its Juárez, Mexico location since 2013. This location ships the control unit to the new ZF Transmission Gray Court in South Carolina, where the technology company is producing the entire 9HP.
ZF Friedrichshafen AG currently employs approximately 1,000 software engineers worldwide. That number will increase in the future since the uptake and potential of active electronic control systems are far from being exhausted. Electronic control systems are becoming increasingly important for ZF, not only with transmissions, but also throughout driveline technology, including hybrid mobility and electromobility as well as in the suspension and for steering systems—irrespective of whether the components are aimed at passenger cars, commercial vehicles or construction equipment.