- The development of a new hybrid drive system for Antonio Carraro compact tractors is consistent with current energy-saving projects in the “Non Road Mobile Machinery” NRMM sector
- The project sets the strategic objective of reducing harmful emissions as mandated by the PNRR Piano Nazionale di Ripresa e Resilienza (National Recovery and Resilience Plan) and by the Next Generation calls for proposal issued by the EU
For the engineers of the AC Research & Development department who worked in collaboration with Ecothea (start-up of the Polytechnic of Turin, specialised in the design and prototyping of electric vehicles for applications on agricultural machinery), the challenge was just as ambitious as it was exciting.
The aim was to build a compact tractor with hybrid technology, based on the most complex model of the Antonio Carraro range. An isodiametric tractor with reverse drive and articulated frame, keeping in mind the typical DNA of compact tractors designed for specialised agriculture.
The result is the SRX Hybrid, a compact vehicle equipped with all comforts. A tractor with a 55kW combustion engine (3 cylinders; cc1861; fluid cooled; Common Rail Turbo Intercooler fuel injection system) combined with a 20kW electric motor, for a total of 75kW, equal to 102hp.
The objectives of the SRX Hybrid (diesel/electric) are:
In short, SRX Hybrid (diesel/electric) has several objectives:
• Guarantee the performance level of so-defined conventional machines;
• Reduce pollution; • Reduce fuel consumption and maintenance costs;
• Reduce noise emissions;
• Operate in full electric mode in closed environments (sheds, greenhouses, stables, etc.)
The architecture of the hybrid-electric system makes it possible to exploit the available power of a diesel engine combined with an electric drive system, guaranteeing continuous traction when working with the PTO (with all equipment), during transportation (with trailer), and in material handling works (combining the vehicle with a forklift, loader or equipment for roadworks).
The overall peak power can reach that of the most powerful configurations in the current Antonio Carraro range. Interaction between the two diesel and electric traction motor-generator drive systems is managed by an electronic power control developed specifically for this type of machine. The architecture of the transmission whereby the electric motor is inserted between the diesel engine and the gearbox, has been deposited with an ACHybrid industrial patent.
The electric motorisation in subsequent versions will also be able to work in full electric mode, exploiting the lithium-ion battery charge. In this case, the diesel engine is off and the machine works with zero emissions, in absolute silence.
Autonomy in full electric mode depends on the capacity of the battery pack, which is recharged each time the brakes are actioned when working in descent, or in plug-in mode with recharging via an electric charging station, or else on request of the user.
Considering an average work cycle, the CO2 reduction translates into fuel savings of more than 25%. Not to mention the significant overall reduction in vibrations and noise.
Thanks to the combination of diesel/electric torque, Carraro claim the tractor offers brilliant “starting” performance on take off and during works with specific equipment such as sprayers, cutters, trailers.
As with all Antonio Carraro machines, the compact configuration and weight distribution, even with the hybrid drive system, guarantees maximum stability of the hybrid tractor even on the roughest terrain, remaining “steady” and safe with a turning radius that highlights the typical agility of compact tractors.