Electric systems create new opportunities

To operate effectively in an orchard, amongst top fruit or in a vineyard, tractors need to be robust but also compact and highly manoeuvrable. These attributes have always been successfully combined in the Landini Rex family of tractors, a market leader in the sector providing growers with mechanical muscle for a wide range of operations.

Electric drive and electronic control technologies

Landini manufacturer Argo Tractors aims to sustain the appeal of this popular machine with an R&D project evaluating the potential for electric drive and electronic control technologies to further improve the Rex tractor’s manoeuvrability, fuel consumption efficiency and operator comfort.

Giovanni Esposito, Innovation Director at Argo Tractors, said, “The evolution of our products provides customers with the most innovative solutions to optimise productivity and improve the quality of their work. The Rex4 Electra – Evolving Hybrid has been designed to further enhance the handling, comfort and ease of use of Rex4 tractors, using new technology to guarantee cost-effectiveness but also with an eye to the environment and sustainability.”

Hybrid power

Looking sleek and distinctive with its new Landini family styling, the prototype Rex4 Electra, which won an EIMA show technical innovation award, has a 110hp diesel engine coupled to the tractor’s usual transmission.

This Argo-built unit features electric shifting between forward and reverse, and also between the three powershift speeds, but with the addition of robotised electronic shifting of the mechanical gears – a feature introduced on production Rex4 tractors from the beginning of 2022.

Full-time four-wheel drive

At the front, an Argo Tractors engineered and manufactured suspension beam axle features individual electric motors for each wheel, providing full-time four-wheel drive.

This installation eliminates a prop shaft and differential and two half-shafts from the driveline, and allows individual wheel ‘torque vectoring’ to pull the front end of the tractor through tighter turns equivalent to a 15% increase in steering angle. Operators could exploit this by making more sweep turns instead of forward/reverse/forward manoeuvres, resulting in increased productivity and less wear and tear on transmission components.

An engine-driven generator and lithium-ion battery provide power, with energy recovery technology topping-up when the brakes are applied.

A power management system supervises the operation of all devices and controls the generator and motors via their respective inverters, while also collecting speed and other data from the mechanical powertrain to ensure the two systems work in harmony.

In trials, the addition of electric power with its instantly-available high torque output in what is effectively a parallel hybrid system, has reduced fuel consumption by 10%, says Argo Tractors.

Operator benefits

For the operator, the benefits of electronic control include ‘fly by wire’ gear shifting from a multi-function joystick, which minimises noise and vibration intrusions into the cab; and semi-active cab suspension similar to that already available on high-end Landini tractors.

The Rex4 Electra’s cab, with its flat floor giving easy access and exit, and a more comfortable driving position than ‘straddle’ designs, is supported on two passive suspension elements at the front and two variable rate hydraulic dampers at the back.

Sensors detecting tractor movement and an electronic control system provide continuous adjustment between ‘soft’ settings to absorb vibration, which Argo engineers say is reduced by some 15%, and a ‘stiffer’ set-up to combat more pronounced movements as the tractor works on uneven surfaces or travels along a bumpy road.