AVL’s e-Tractor concept is a modular electrified powertrain platform which can be used for a wide range of agricultural applications.
The platform is composed of a power chassis with interchangeable system modules. The powertrain provides traction plus electrical and hydraulic power. Optionally it can also supply pneumatic power for pneumatic trailer brakes. AVL said that the compact design and the optimized thermal management of the electric powertrain can deliver a reliable and robust product to operators of agricultural machinery.
Thomas Woopen, working at the Development Engineering Vehicle department at AVL Tractor Engineering Germany, said: “The powertrain delivers up to 75 kW in total – 25 kW to each of the two axles in the chassis, 20 kW for the hydraulic circuit and up to 50 kW for an electrically-driven implement.”
“The electric power unit is composed of a high-voltage battery (700 V) with a target for 140 kWh capacity. The charging time for the battery is between 3 and 5 hours in order not to stress the single cells too much and guarantee a long battery life,” continued Woopen. “For the prototype a Li-Ion air-cooled battery was chosen, but we are working on solutions with solid-state liquid-cooled batteries.” For safety, the powertrain features a high-voltage interlock that automatically disconnects the battery in case of problems.
“The system’s architecture includes three inverters, one per each of the axles and one for the hydraulic circuit. Hydraulics for steering and braking are redundant systems and so are ready for autonomous drive.”
Three modules are available for implements on the top of the chassis, with 50 kW for each module, insuring a flow of 40 L/min for a hydraulic pump. In addition, there are four further slots at the front, rear and at each side of the chassis.
An optional pneumatic unit can be powered, to activate the trailer’s pneumatic brake. The unit operates a compressor with 3 kW power, which is driven hydraulically considering that the operation of the brake is not needed for long periods and therefore does not affect the system’s efficiency.
The axles are off-the-shelf units adapted by AVL, while rotor and stator of the electric machine is a Parker product. The rest of the components and the control system are by AVL.
“The AVL e-Tractor concept could feature autonomous operation, with a special module that will include cameras, ultrasonic sensors, radar sensors, and GPS; this add-on is currently under testing,” concluded Woopen.
The e-Tractor is a fully AVL-funded project and the company is in negotiation for a pilot customer.