ZF Friedrichshafen AG offers a broad product and services portfolio for the electrification of commercial vehicles. The two main emphases include all-electric drive solutions for urban vehicles with limited range, and hybrid technologies for longdistance transport applications where combustion engines continue to be indispensable in the long term. Its newest development is an all-electric central drive that can be used in different bus systems and city delivery trucks. This is a convenient addition to the currently available AVE 130 electric portal axle. ZF has adapted its electric axle drive used in passenger cars for application in light commercial vehicles as well. Furthermore, ZF has hybrid solutions in its portfolio, for example, the TraXon Hybrid for heavy-duty trucks. The company can draw on its electronics and system integration expertise as well as its energy management experience which is vital in these applications.
High-torque, powerful diesel engines remain critical components for many commercial vehicle applications. Nevertheless, the electrification of commercial vehicles has strong potential because for some applications and market regions, the hybrid or the allelectric drive is already a better alternative. “Many commercial vehicles with limited daily mileage can already be operated using all-electric drives,” says Fredrik Staedtler, head of the Commercial Vehicle Division at ZF. In many large metropolitan cities in Europe and Asia that already have strict emissions regulations, these systems are even mandatory. Fleet vehicles are often used in a “return-to-base” operation, which means that delivery trucks and buses can return to the fleet lot or bus depot overnight and easily be re-charged.
ZF has developed a fully-electric central drive that allows for zero pollution city buses and delivery trucks. It is the newest member of an already existing product portfolio that also includes the AVE 130. In expanding its portfolio for buses, ZF’s new central drive is intended both for smaller buses as well as high-floor applications, while the popular AVE 130 is used particularly in low-floor applications. Both concepts will soon also be available as a whole system; in other words with a torque control from ZF and with ZF approved inverters in order to provide customers with a perfectly fine-tuned complete system.
For hybrid use in heavy commercial vehicles, ZF has developed yet another product: TraXon Hybrid, which has an electric motor installed between the combustion engine and the transmission. This parallel hybrid incorporates all hybrid functionalities into a 40-ton truck, including recuperation of braking energy, purely electric maneuvering as well as turning off the engine at a standstill (start/stop function) and boosting the combustion engine. One feature that is particularly attractive for many applications is that, in generator mode, the hybrid module can also supply power to other units during refrigerated transports, for example. With a view toward future processes at the truck or bus depot, ZF has equipped its Innovation Truck 2016 with the TraXon Hybrid which can already maneuver autonomously and purely electrically. Apart from being installed in truck applications, TraXon Hybrid is also suitable for coaches, where the hybrid drive boasts the same advantages.
The new central drive and the AVE 130 electric portal axle enable bus manufacturers to fit their buses with hybrid systems. They are designed as serial hybrid drives where the combustion engine merely has the job to generate electricity and no longer drives the vehicle, an approach particularly useful in city traffic.
ZF has taken a central axle drive from the passenger car sector and applied it to light commercial vehicles. The passenger car version of the fully integrated system will go into volume production with a European carmaker in 2018. An electric motor is combined with a two-stage single-speed transmission, a differential and power electronics to form a highly-integrated, extremely compact unit. Generating 150 kW, the system is so powerful that it can also be used in light commercial vehicles. “Identifying synergies between passenger cars and commercial vehicles has always been an asset of ZF and this is also holds true for our electrification strategy,” emphasizes Staedtler.
Another company strength is its electronics expertise – making the systems intelligent and efficient. The software is essential for managing the energy in the vehicle and is therefore ultimately responsible for efficiency and the actual achievable range. The software settings are also in charge of managing the convenient switching between different driving modes and meeting safety requirements. As a system integrator, ZF’s expertise is additionally valued by customers from the commercial vehicle industry. A good example is the efficient integration of recuperation into braking management – this is when the electric motor, in generator operation, generates power and at the same time lightly brakes the vehicle without the brakes having to actuate.