The new ZF TraXon automatic transmission system also allows for the use of hybrid technology in long-distance traffic. In the TraXon Hybrid configuration, an electric motor is located in the clutch bell housing – this means that all hybrid functions can be used in heavy trucks: From the recuperation of braking energy, purely electric maneuvering as well as switching off the engine at a standstill (start-stop function) to boosting the combustion engine. Especially attractive to many applications: In generator operation, the hybrid module can also be integrated into the power supply of other units - for example, for refrigerated transports. In any case, the TraXon Hybrid contributes to reducing fuel consumption and emissions of trucks.
For many years, experts of the commercial vehicle industry were of the opinion that hybrid technology would particularly establish itself in delivery traffic. Here, in terms of percentage, the most significant fuel savings of about 20 percent can be achieved with hybrid technology: In the driving profile of inner-city routes, the start-stop function, the recuperation of braking energy, as well as purely electric driving show their advantages very clearly. However, recent investigations carried out by ZF have shown that hybrid functions have a significant potential to reduce fuel consumption for heavy commercial vehicles as well. Indeed, the percentage of approximately 5 percent is lower here. However, in the face of higher fuel consumption and the considerably higher annual mileage, the use of hybrid technology is profitable here, too. Thus, hybrid trucks are more economical in use and the hybrid infrastructure in the vehicle amortizes within a reasonable time.
The TraXon Hybrid uses an electric motor with a performance of 120 kW and a torque of 1,000 Nm. It is integrated into the vehicle via a SAE1 connection and uses the power electronics to propel the vehicle electrically. A dry clutch is integrated into the hybrid module to decouple the combustion engine, e.g. in the electric mode and during recuperation, but particularly to serve as a conventional starting element.
While braking, the electric motor switches to generator operation and feeds power to the battery. When accelerating, this electric energy can be called up again if the heavy truck starts rolling without using the combustion engine, and the diesel engine is only activated if necessary (start-stop function). For shorter distances - for instance, indoors (e.g. a hall) - purely electric maneuvering is also possible. The batteries' energy can also be used to support the power development of the diesel engine. In the case that this "boosting" is included in the vehicle configuration as torque distribution from the very beginning, the diesel engine can also be designed economically ("downsizing"). This again leads to an increase in efficiency.
The TraXon Hybrid offers further potential as commercial vehicle manufacturers can implement additional fuel-saving functions. "Coasting" could be introduced to the driving strategy of the hybrid transmission: When rolling, the diesel engine is switched off so that in these driving phases, diesel is not even consumed at idling speed - a savings potential of up to 3 percent. The hybrid technology is especially attractive when integrated into the energy management of vehicles with electric auxiliaries. In the case of, for example, a refrigerated transport, the electric energy recovered during braking by means of a generator can be "recuperated" directly to the cooling power instead of a battery. Consequently, the refrigerant compressor needs less power from the diesel engine. This facilitates noticeable savings in practical use. In future, electric PTOs ("Power-Take-Offs") are also attractive to municipal commercial vehicles because many auxiliaries (e.g. for waste collection vehicles) can be implemented with more electric efficiency and at a lower noise level compared to today's commonly used mechanical PTOs, which, when in operation, cause an unpleasant noise for the residents due to the speed of the diesel engine.
There are also electric auxiliaries in the driver's cab - from the microwave to the air conditioner. They can be run with the TraXon Hybrid without switching on the engine. Thus, comfort gains for the driver can be combined with fuel and emission savings.