ZF TrailTrax: testing to the extremes
ZF has revealed details of its field testing procedure for its TrailTrax electrified trailer system.
In the final stages of product and system development, field testing with various vehicle combinations and under different climatic conditions is crucial, says ZF.
This is also true for TrailTrax, which integrates ZF’s in-house developed AxTrax 2 e-Axle, Trailer EBS and battery system box.
ZF’s modular e-drive system for semi-trailers enables the recuperation of brake energy and provides additional traction for the truck/trailer combination. Consequently, TrailTrax helps ICE trucks save fuel and reduce CO2 emissions or extend the range of EV trucks.
The system intelligently senses operational driving conditions to activate either the AxTrax 2 recuperation mode or traction support. Vehicle combination safety is ensured by ZF’s Trailer EBS and the e-Axle Control Unit, which act like a sensor-enabled digital kingpin.
By connecting to the truck via a standardised CAN interface, a TrailTrax electrified trailer can be combined with current trucks, regardless of the brand or driveline technology used. This makes TrailTrax a versatile key technology for both trailer builders and fleets to meet upcoming decarbonisation legislation.
To obtain a detailed picture of the system’s real savings potential, extensive test kilometres are necessary, says ZF. This was addressed in autumn 2024 with detailed driving tests in Sweden. Various trucks, both conventional and electric, from well-known manufacturers were used to gain precise insights into the technology’s real savings potential, regardless of the truck driveline.
“This is particularly important for fleets with a mixed vehicle park to ensure that ZF’s TrailTrax technology operates smoothly with any current type of truck,” said the technology provider.
In addition to numerous simulations and investigations on the ZF test track in Germany, winter testing is indispensable, ZF says.
“To ensure that ZF’s modular e-drive system for semi-trailers is a reliable solution for customers, the system must function flawlessly in all weather conditions. Therefore, two TrailTrax trailers (a reefer and a container chassis) were sent to the cold north in Finland.
“The aim of the winter test is to evaluate all system components, including the e-drive axle, battery system box, control, and sensing, to ensure that the required functions and integration of each individual components and the entire trailer architecture operate flawlessly, even under extreme winter conditions.”
In addition to functional tests of the system and its components, driving tests were conducted, which are otherwise difficult to simulate and could not be performed under real conditions in Germany.
“Specifically, driving-off manoeuvres on different quality of snow and icy surfaces with varying gradients were tested,” said ZF.
“The driving tests aimed to optimise the drive-off behaviour and acceleration to higher speeds. This way, TrailTrax’s traction benefits for driver support, such as drive-off support, acceleration boost, and uphill support, could be verified.
“These functions support the driver in severe situations with up to 80 per cent more traction on slippery ground, up to 50 per cent acceleration time reduction and improved uphill driving performance.
“In fact, equipping a trailer with the TrailTrax system offers All-Wheel-Drive performance, providing a safety advantage for the driver.”
Effective braking is as crucial as acceleration, says ZF; therefore, the braking behaviour of the entire combination was examined for two reasons: efficiency and safety.
“On one hand the recuperation potential on ice and snow with reduced friction coefficients was investigated. On the other hand, Anti-Lock Braking System (ABS) functions were tested both in longitudinal dynamics and lateral dynamics during cornering to prove vehicle combination safety in all conditions.
“The findings from all these tests directly contribute to the finalisation of the TrailTrax system development.”
