Coming soon: The new DLG rolling testbed – a unique dynanometer

At the DLG Test Center, automotive test engineers are putting the last touches to the new DLG PowerMix rolling testbed. Automotive Engineering project manager Andreas Ai gives us an update.

Mr. Ai, how is work on the DLG PowerMix rolling testbed progressing?

Advertisement

Externally, the building and the roof between the new facility and the existing tractor test field have been completed. Inside the building, the testbed itself has also been completed. The same applies to the measuring equipment and the load units.

Currently we are linking the individual load units with the measuring equipment and the process automation system. The next step is to verify the functionality of all sensors and measuring devices installed. After that, the new hydraulic load unit and the measuring system, a development by testbed supplier MAHA, will be subjected to extensive shakedown testing. These initial trial runs will provide further insights into any adjustments still necessary. At the same time, we are setting up all the routines that make up the testing cycles and evaluation processes.

What aims is DLG pursuing with this new PowerMix testbed?

Without doubt, the new test – the only one of its kind in the world – is an investment in strengthening the confidence of manufacturers and farmers alike in the DLG PowerMix test results. In our opinion, there is no other measuring technique that reflects in-field tractor applications as realistically as our PowerMix methodology, which supplies buyers with valuable information to make a viable purchase decision.

At the same time, the new test stand will consolidate our endeavours to chart an alternative approach to the existing emissions regulations for tractors. After all, we do not believe that more stringent regulations will be the road ahead, if they continue to apply to engines only, because they lead to manufacturers focussing solely on the refinement of engine technology at the expense of disparate R&D costs. And it is the retail customers who will ultimately pay the price to cover for these costs, not only at the time of purchase but possibly also in the form of higher running costs.

What would an alternative look like?

The new testbed will enable us to simulate field applications much more easily to measure emissions and relate the results to the work delivered. Admittedly, the engine is at the heart of all tractor efficiency, and for this reason regulations have focused on engines up to now. But it is not the only parameter to look at. Instead, it would make much more sense to widen the approach and look at the machine as a whole system. That means we must not restrict emission control to engine output but to the tractor's overall output, an approach that could be beneficial to all parties involved. The manufacturers will be given the opportunity of refining all the components on a tractor, including the engine, and bring all systems in tune with each other. The environment will also benefit because exhaust levels will drop as output levels increase. Lastly, and very important to everybody here at DLG, farmers will get a more efficient machine for a reasonable price.

Key data – the DLG rolling testbed/dynanometer

Building

• Floor area 20 x 20m

• Height 13.25m

• approx. 1,100 m³ of concrete

• 135t of concrete steel

• 30t of section steel

Testbed foundation

• Floor area 9 x 9m

• approx. 90m³ of concrete (equating to approx. 210t of concrete excl. concrete steel)

Rolling testbed

• Individual motor weight 18.5t

• Individual motor mount 10.5t

• Weight per roller 5.5t

• Weight per load unit approx. 35t

• A hydraulic pull-down facility imposes a variable load of up to 200kN on the tractor

Load simulations:

• Axle load max. 30t

• Variable wheelbase 2.05-6m

• Continuous drawbar load 90kN, temporarily 112kN

• Total load 700kW

Pto test stand

• Total load 700kW

• Brake load 7,000Nm at > 1,400rpm

Hydraulic test stand

• Total load 150kW

• Max flow 600l/min

• Fixed displacement swashplate motor as hydro motor

• Load unit Asynchronous machine

Electric load unit

• Total output planned 150kW

Air conditioning system

• Air flow rate 100,000m³/h

• Temperature inside the testing hall 25°C

• Louver cross section 9m²

• Output rate 10km/h

Heating system

• Heat exchanger, exhaust heat is recycled during testing

• Heat pump for extra heating

The DLG PowerMix test

The DLG PowerMix test measures a tractor's fuel consumption by imposing load on its pto, hydraulic system and drawbar and by mixing these loads in simulation of real-life field application. Each test comprises 14 individual test runs which are based on specific target curves that were derived at by measuring practical tractor outputs in the field using real implements. The individual fuel consumption rates measured are converted into specific consumption rates, i.e. in grams per kilowatt hour (g/KWh), and this figure is used to compare the rates of the individual tractors in their individual power brackets. The DLG-PowerMix test can be retrieved from the internet at www.DLG-Test.de/powermix.

The new DLG PowerMix rolling testbed is an investment in the future of DLG tractor tests. Besides, the new facility also offers the capability of testing high-horsepower tractors now as well and will expand DLG's testing options. The rolling testbed is supported by the Federal Ministry of Food and Agriculture by resolution of the German Bundestag.

The DLG Test Center for Technology and Farm Inputs

Based in Groß-Umstadt near Frankfurt, Germany, the DLG Test Center for Technology and Farm Inputs sets the benchmark for tested farm equipment and inputs and is the leading provider of independent equipment testing and certification services. Using advanced measurement technology and practical testing methods, DLG test engineers put developments and innovations to the test. As an EU-notified test laboratory with multiple accreditations, the DLG Test Center for Technology and Farm Inputs provides farmers and contractors with vital information that is used for their decision making. Its recognized equipment tests and DLG tests help readers plan their investment in farm equipment and inputs.