Electric drives in agricultural machineryдата создания: 07.11.2011
The "electrification" of the tractor
At Agritechnica, Linde Hydraulics will demonstrate the advantages of using electric drives in agricultural machinery – both for manufacturers of work machinery and for their users. Two examples: When the conveying screw and ejector of a fertiliser spreader are driven by compact, speed-controlled electric motors, the quantity and the spreading distance of the fertiliser output can be regulated much more precisely. And if an air conditioning compressor is electrically driven, it can be switched on and off as required – this saves fuel and reduces the power requirements of the combustion engine.
A million electric cars should be on Germany's roads by 2020 – this is what the German government wants, and a special "National Platform for Electric Mobility" has been founded together with industrial heavyweights in order to achieve this goal.
"Electrification" of tractor drives as a future trend
How many tractors with electric drives will be ploughing, sowing and harvesting in the agricultural industry by 2020? There exists no official target. According to a prediction from Linde Hydraulics, in the coming years there will be new models that are more heavily "electrified" than their predecessors. Above all, auxiliary drives and power take-offs, as well as functions such as air-conditioning and the generation of compressed air, will be driven by electric motors and switched on and off as required by electronic controls.
At Agritechnica, the Linde Hydraulics "Electronic Systems & Drives" (ES&D) Division will be showcasing examples of this future trend, and can point to decades of expertise in this field — the company has already developed and built electric drives for several million industrial trucks, i.e. forklift trucks and tow trucks. The electric drives have also been offered outside the Group since 2010 — with great success.
Switching auxiliary and secondary drives on and off as required
Air conditioners, compressors and fans are secondary drives that work considerably more efficiently when they are driven by separate electric motors and controlled by the LINC 2 electronic control from Linde Hydraulics.
Electric compressor and fan drives relieve the load on the combustion engine and contribute to fuel savings.
With this configuration, each unit is switched on and off as required as well as being operated at a variable speed, thus saving energy. Fans have the added advantage that the user can clean the unit by briefly reversing it.
In addition, the pumps for the hydraulic attachments can be operated electrically.
Variable-speed electro-hydraulic drives for auxiliary devices allow precise control of work functions.
Linde Hydraulics offers a highly efficient "Powerpack" for this purpose that consists of an electric motor, gear pump, power module and LINC 2 control that are exactly calibrated to each other.
If the manufacturer of the tractor decides in favour of electric power for auxiliary drives, he also benefits from the fact that the combustion engine needs to produce less power. In this way, tighter emission regulations (key word: Tier 4b) can be met without having to change the make or the dimensions of the diesel engine. Overall, the power requirements of tractor combustion engines can be lowered by up to 25 kW through consistent electrification of the auxiliary drives.
Fertiliser spreaders: Precise control of fertiliser quantities and spreading distance
The advantages of the electric drive in practice can be demonstrated using the example of a fertiliser spreader. Normally, the ejector and the conveying screw are powered by the central on-board hydraulics. If both components are driven by a compact speed-controlled 2-kW motor, they can be controlled separately and precisely so that the quantity (conveying screw) and the spreading distance (ejector) can be set as required.
Compact 2-kW drives for the ejector and conveying screw can be regulated and allow precise distribution of the fertiliser.
This offers particular advantages when the fertiliser output is controlled by a "precision farming" system. Distribution of the fertiliser can then be precisely controlled according to predefined parameters – this saves fertiliser and guarantees a homogeneous growth of the crop.
Yard loader with electric drive wheel unit
Diesel or electric drive? Any company that buys a forklift truck must ask this question, and in the not-too-distant future this decision may also have to be made by farmers who require a yard loader. Electrification is handled by a 16.3-kW central drive unit that operates highly efficiently and has been proven to work in the electric car Karabag NEW 500 E and other applications.
Yard loaders with electric drive motors are both emission-free and virtually noise-free but are just as powerful as conventional machines with a diesel engine.
The advantages offered by a yard loader with electric drive include emission-free driving, which makes particular sense for indoor operation, especially in the ecological production of milk. In addition, the loaders operate in a virtually noise-free manner, causing less disturbance to livestock when they are being moved around in the barn. Since yard loaders are normally only used for short work cycles of no more than two hours, the batteries can be designed to compact dimensions.
Summary: Electric drives – a hot topic, even for agricultural machinery
As the examples show, electrification of the drive train is also a topical subject in the production of agricultural machinery. Linde Hydraulics can support manufacturers of mobile work machines when designing the system and choosing components, and subsequently deliver a complete drive system including cable harness and operating devices. In terms of software, the systems on offer include customer-specific programming of controllers and their technical integration into higher-level motor and vehicle management systems.
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