The complete process chain – from the production and the quality determination and standardisation of biofuels to the performance and emission properties of engines using biofuels – has been subject to the research of the Technology and Support Centre for more than 25 years.
Established and novel biofuels are analysed, developed and ecologically assessed in the laboratory. At the tractor test stand, the performance, fuel consumption and exhaust emissions of engines suitable for running on vegetable oil are determined. Accompanying field tests give indications of their practical suitability. Finally, the use of vegetable oils as lubricants or component of biodegradable covering materials is tested.
The real driving emissions of an EU stage IV forest harvester were measured four times within five years to monitor long-time emission behaviour. In this period, the harvester worked 7650 h in total, thereof 6300 h with pure rapeseed oil fuel DIN 51605 (R100) and 1350 h with conventional diesel fuel initially. Data analysis according to relevant EU regulation 2017/655 shows that the emission behaviour complies with the legal requirements of exhaust gas stage IV within the five years under consideration.
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Pure rapeseed oil fuel (R100) according to standard DIN 51605 is a greenhouse gas saving option for the mobility sector. With its high energy density close to diesel fuel, R100 is suitable to operate non-road mobile machinery with a high power demand and long operating time, where electric drives reach their limits. Advantages are indicated for its use in environmentally sensitive areas like agriculture since R100 is highly biodegradable and non-toxic. However, R100 is characterised by differing physical and chemical properties compared to diesel. The objective of the research is to investigate the differences in the ignition and combustion behaviour of R100 compared to diesel fuel (DF). For this purpose, a constant volume combustion chamber is used, which is equipped with a modern solenoid injector for engines of non-road mobile machinery.
The exhaust emissions of tractors during field work can only be measured with great effort. A test method for determining the real exhaust emissions of tractors on a tractor test stand has now been developed at the TFZ. The method enables the measurement of pollutants under repeatable conditions, independent of weather and implement.
The article is downloadable from Springer for a fee (forwarding via link).
The published study evaluates whether it is possible to use rapeseed oil fuel in forestry machinery and what greenhouse gas savings can be achieved. The results are based on a field test lasting 2100 operating hours, testing also the real driving emissions of a modern harvester of the Bavarian State Forests that has been adapted to rapeseed oil fuel. It could be shown that the use of rapeseed oil fuel is technically possible in forestry and that greenhouse gas emissions can be saved by replacing fossil diesel fuel. In addition, due to the low toxicity and good biodegradability rapeseed oil fuel contributes to soil and water protection in the forest.
Scientists at the TFZ have published new results on the long-term operating behaviour of tractors suitable for vegetable oil. Results from several years of studies on 18 tractors that are adapted to use rapeseed oil fuel according to DIN 51605 are evaluated. The tractors worked extremely reliably for more than 50,000 hours on various farms in Bavaria. Recurring measurements of engine performance, fuel consumption and exhaust emissions showed hardly any differences between rapeseed oil and diesel operation. The measurements also show that both fuels meet the legal emission standards. However, rapeseed oil fuel has clear advantages: compared to diesel, up to 90% greenhouse gases can be saved. At the same time, valuable protein feed is produced, the regional economy is strengthened and a contribution is made to soil and water protection.
Scientists in the subject group "Liquid Biofuels, Biolubricants and Process Materials" of the Technology and Support Centre have published a paper in the famous journal "Biosystems engineering". In the study six representative tractor test cycles were generated from 206 hours of recorded ECU and GPS data. Furthermore the in-field recorded engine operation profiles on the tractor test stand could be replicated successfully. As a result the real work-based emissions of NOx, HC, CO and particles are generally lower than those in legal-based test cycles. Thereby rapeseed oil fuel features a high potential for greenhouse gas reduction.
Publication in the peer-reviewed journal Fuel Processing Technology: In the article fundamental findings on the ignition behaviour of vegetable oils compared to reference fuel mixtures are presented. The reference fuel mixtures are used to determine the cetane number, a measurement of the ignitability of diesel fuels. The research was carried out with the Advanced Fuel Ignition Delay Analyzer - AFIDA. The results can be used for the further development of a test method for evaluating the ignitability of vegetable oils or other alternative fuels and support work on the further development of fuel standards.
Scientists from the TFZ presented new findings on the influence of fatty acid composition on the ignition and combustion behaviour of vegetable oils in the international peer-reviewed journal FUEL. The results are based on experimental research carried out with the new Advanced Fuel Ignition Delay Analyzer - AFIDA. The results can be used to further optimize the combustion of rapeseed oil fuel and other vegetable oils in modern engines and are now available to the international research community.
Despite the growing interest in real operating emissions measurement and analysis of modern diesel and rapeseed oil powered tractors have been little studied. Here under real operating and ambient conditions, the emissions vary compared to the measurements on the test bench. Using a portable emissions measurement system (PEMS), TFZ has measured the emissions of a Fendt Vario 724 S4 with a Euro IV engine running on rapeseed oil fuel in accordance with DIN 51605 during ploughing in the field and on the tractor test stand.
Scientists of the subject group “Liquid Biofuels, Biolubricants and Process Materials" of the Technology and Support Centre have published a new paper about the “Emission behaviour of vegetable oil fuel compatible tractors fuelled with different pure vegetable oils” in the renowned journal FUEL. The scientific article was positively evaluated in the peer-review-process by international experts. Since the last 80 years FUEL is one of the leading journals where new fundamental research work in fuel sciences is published and discussed. In the research article new results concerning the influence of the molecular structure of different vegetable oils on the emission behaviour of vegetable oil compatible tractors are presented.
Scientists in the subject group "Liquid Biofuels, Biolubricants and Process Materials" of the Technology and Support Centre have published a paper in the renowned journal "Biomass & Bioenergy". In this peer-reviewed journal research results in regard to production and usage of renewable resources are being published to an international audience. The article covers fundamental research, conducted at the Technology and Support Centre, that furthers the understanding of the use of vegetable oils as fuel for combustion engines.
Agriculture and forestry face the future challenge of finding climate-friendly and regenerative methods of powering their field and forest machinery. Alternative fuel and drive concepts have been presented by industry in the past but, so far, these have been unable to establish themselves against the dominating diesel-fuelled internal combustion engine. Such concepts include internal combustion engines and the fuels fatty acid methyl ester “biodiesel”, rapeseed oil/vegetable oil fuel, “HVO” hydrogenated vegetable oils and biomethane, but also electrical drive with energy supply via fuel cells with hydrogen or using accumulators. The alternatives were discussed and evaluated according to 14 criteria in a technical discussion with experts from industry, associations and scientific institutions. Currently, the use of rapeseed oil fuel and biodiesel in internal combustion engines for agricultural and forestry work machinery is most advantageous for more climate protection and resource saving and is simultaneously rapidly applicable.