DLG TestService GmbH operates one of the world’s most powerful all‑wheel chassis dynamometers for measuring performance and consumption of heavy-duty vehicles at its test center in Gross‑Umstadt, Germany. The primary focus is on testing tractors, although performance and consumption measurements for other commercial vehicles and trucks are also part of the portfolio. Test engineer David Herrmann explains how these tests work in practice.
Mr Herrmann, you work as a test engineer in vehicle technology at the DLG Test Center in Gross Umstadt. What options do you have for measuring the performance and fuel consumption of tractors?
At the DLG Test Center, we have several ways of testing tractors. We can either carry out measurements on the test track or use different test benches, depending on the application. For example, we use what we call a brake truck to measure drawbar power as well as fuel and AdBlue consumption. We also have a lift and hydraulic test bench, which allows us to determine both hydraulic performance and the lifting capacity at the front and rear linkage. Then there is the PTO dynamometer, which we mainly use to measure engine output and the associated consumption of fuel and AdBlue. And finally, we have the chassis dynamometer.
Are there defined limit values or target benchmarks for these tests? Who specifies them?
The tests are carried out either according to customer specifications, using the DLG’s own PowerMix consumption cycle, or based on the OECD Tractor Codes 2 and 5. These codes allow us to evaluate tractor performance using internationally standardised testing procedures.
For these OECD Tractor Codes, the DLG Test Center is the only certified test laboratory in Germany. The results we generate help create transparency and comparability between tractors worldwide, which in turn supports international trade.
![[Translate to English:] Foto: DLG](/fileadmin/_processed_/0/b/csm_Herrmann__David_e022f99fb0.webp)
What exactly is a chassis dynamometer and what is it used for?
For testing, the vehicles are positioned on four steel rollers, each with a diameter of two metres. These rollers can be driven and braked by electric motors. The system can be adjusted to different wheelbases between 2.05 and 6.00 metres, which means we can accommodate a wide range of vehicle sizes.
The maximum axle load is 30 tonnes, so the total vehicle mass can reach up to 60 tonnes. Each wheel can transmit a tractive force of up to 135 kilonewtons.
We mainly use the chassis dynamometer for tractor testing, but we also carry out performance and consumption measurements for other commercial vehicles and trucks. It is even possible to measure the complete efficiency chain of electric power consumption in hybrid and electric vehicles.
When it comes to consumption, we can measure both fuel and AdBlue usage for tractors with up to around 1,000 horsepower. A major advantage of the system is that it can simulate realistic driving conditions. The front and rear axles can be driven and braked either synchronously or with a time offset, which allows us to reproduce real operating scenarios very closely.
In terms of what we actually test, this ranges from driving performance such as acceleration and tractive force to fuel and AdBlue consumption. We also look at the calibration of engine, transmission and hybrid control systems, as well as thermal management for engines, electric drives and batteries. All of these tests can be carried out under controlled climate conditions, because the test hall can be adjusted to temperatures between minus 10 and plus 40 degrees Celsius.
What makes this chassis dynamometer special?
One key feature is that we can run both axles synchronously, which is essential when testing modern all‑wheel‑drive systems. The system also allows us to apply programmable load profiles, including gradients, aerodynamic drag, vehicle weight and different driving scenarios. This means we can realistically simulate both field work and transport operations. At the same time, we precisely record power output and torque.
What types of tests do you typically carry out?
One of our core tests is the driving cycle test that we developed ourselves, the DLG PowerMix. In addition, we conduct standardised consumption cycles for commercial vehicles and also run tests based on specific customer requirements.
Beyond that, we regularly carry out endurance and durability testing, analyse recuperation behaviour in commercial vehicles and support manufacturers during development. We also test fuel and oil additives.
What makes the DLG chassis dynamometer one of the few of its kind worldwide?
Its size is definitely a key factor. We can test very large and heavy machines with axle loads of up to 30 tonnes. Another important aspect is that we can apply different types of loads simultaneously, for example drive power of up to 700 kilowatts, PTO power of up to 700 kilowatts and hydraulic power of up to 150 kilowatts.
In addition, we can control the temperature in the test hall to simulate both cold and hot conditions. This allows us to take environmental influences fully into account in our measurements.
A particular highlight is the PowerMix cycle, which was developed specifically for tractors by our test engineers here at DLG.
With axle loads of up to 30 tonnes, simultaneous load testing and the dedicated PowerMix cycle, the chassis dynamometer is one of the most powerful systems of its kind worldwide.
David Herrmann
Technology & farm inputs – Testing expertise for the agricultural sector.
We test tractors, agricultural machinery and farm inputs in accordance with DLG standards and international norms – independently, with a practical focus and certified. Our services are complemented by bespoke testing solutions for research, development and quality assurance.
DLG chassis dynamometer – Precise Measurements Under Controlled Conditions.
The DLG chassis dynamometer for measuring the performance and fuel consumption of agricultural machinery and commercial vehicles combines the highest standards of functionality, flexibility, and precision and features an extremely high-performance measurement system.
→ Visit the DLG Test Center
→ Discover the DLG chassis dynamometer
