At this year´s CONEXPO ZF presents several ground-breaking innovations that pave the way for the construction site of the future. Guided by the principle of zero emissions, ZF strives to achieve the ambitious claim of enabling compact work machinery such as compact loaders to operate emission-free in the future. Technology leader ZF is setting new standards for electrical drives, especially when it comes to integrated system solutions.
ZF eTRAC – Tailor made solution for electric compact vehicles
Compact vehicles such as loaders, mini dumpers or telehandlers are a promising segment in the area of electro mobility. The eTRAC driveline system with its 48-volt e-motor developed by ZF provides the necessary emission-free drive. Additionally, the Group also acts as a system supplier. Not only does the company deliver the electric unit, but it also offers a combination of front and rear axles, drives, inverters and an electric Drive Control Unit (fig. 7). This best in class solution achieves the same output as conventional drivetrains, without compromising on performance factors such as traction and top speed.
With 48V operating voltage, the application falls under the Low Voltage Directive. This offers enormous benefits in terms of safety components and vehicle maintenance. Servicing costs are therefore kept to a minimum.
The ZF driveline for electric compact loaders, uses an e-motor and transmission which have been developed especially for this application using actual measurement data from conventional compact loaders. This allows for greater levels of cycle efficiency and avoids the need for load reduction (derating) of the components. To guarantee a steady performance, unlike its competitors’ products, ZF opts for a liquid cooling medium. The use of liquid cooling in the e-motor and the power electronics also ensures consistent and lasting performance in construction machinery applications. An e-motor and hydraulic pump make up the electric hydraulics system.
ZF has found a ‘best in class’ solution for power density. The solution is unrivalled on the market in the 20kW (continuous performance) and 48V performance classes. For outputs ranging from 20kW/48V, 30kW/96V to 42kW/650V, a modular e-motor has been specified for the drive. High levels of system efficiency are guaranteed, and the drivetrain can be combined with standard ZF axles for compact loaders. It has been designed to extend the continuous performance up to 42 kW – and with an operating voltage of 650V. The eTRAC project for electric compact wheel loaders aims at developing a system solution for machines with an unladen weight of up to 8 t.
To make the most of the special properties of e-motors, the development team has chosen a new, high-speed transmission to complement the ZF modular kit. Vehicle platforms generally remain the same as conventional and alternative drivetrains become a reality on a single machine family. That makes it possible to keep the entire system's costs and complexity to a minimum.
ZF CMe – Benchmark for electric mixer drives in the market
ZF offers an electric drum mixer drive teamed with a battery as an energy source for mixer trucks. This guarantees customers security when investing in and planning the procurement of new transit mixers. Traditional mixer drum drives operate via high pressure hydraulics that require the truck’s combustion engine to drive a PTO connected to the hydraulic pump. The new plug-in hybrid concept replaces the hydraulic motor in the mixer drive with a pre-connected electric motor and the hydraulic pump with a generator. The truck's engine can, therefore, be turned off while on the construction site. The mixer system, operating autonomously from the truck allows the drum to turn with no emissions, thanks to the electric motor. The battery can be charged on the mixer system by cable and by a built-in generator when being driven (fig. 8).
Some of the benefits of this plug-in hybrid system for mixer trucks with electromechanical drum drive include compactness, low weight, and durability even for strenuous construction applications.
The system satisfies all the expectations for performance and productivity found in traditional mixer trucks and combines them with the extensive benefits and opportunities that electromechanical systems have to offer. The ZF CMe drum drive is the first electric product for truck mixers to go into production (fig. 9).
Up to 15.7 yd3 (12 m3) mixing capacity
The energy source for the drive system is a powerful battery that has been fitted to the trailer. During operation, the vehicle can access 60 kW continuous power and a peak power of 125 kW for a shorter period.
The 650 V used by the high voltage system was specially selected for reduced power loss. Further, this is emerging as the standard in the electric commercial vehicles sector.
The interplay between ZF technology products makes the mixer truck an efficient vehicle, ready to meet future market demands.