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    Item type:Publication, Access status: with files ,
    Investigation of oil emission mechanisms in a marine medium-speed dual-fuel engine
    (Sage Publications, 2024-05)
    Hochfellner, Baptiste
    ;
    Wirz, Friedrich
    ;
    Pryymak, Konstantin
    ;
    Preuß, Ann-Christin
    ;
    Matz, Gerhard
    Pilot-ignition Otto marine engines are known for greatly reduced emissions of air pollutants (sulphur oxides, nitrogen oxide, particulates) compared to marine diesel engines. However, lubricating oil emissions still are about one order of magnitude higher than in land-based systems. To identify reduction potentials, a better understanding of oil emission mechanisms has to be gained. For this purpose, mass spectrometric oil emission measurements and fluorescence lubricating film thickness measurements were performed on a medium-speed marine engine. With the fluorescence measuring system, the varying lubricating oil film on the cylinder wall can be visualised and analysed in sub-crank-angle resolution. By applying the developed calibration method to the measurement data, the oil film thickness can be determined in µm. It is shown that the oil film left by the piston rings on the liner as it moves down is almost halved after ignition compared to during intake stroke. The authors have further been able to detect and time operating point dependent ring rotation and investigations show a connection between ring rotation and cylinder liner temperature distribution. Aligning ring gaps allow blow-by to happen. This and other high intensity events such as engine knock, load shedding or the transition from diesel-mode to gas-mode, heavily disturb the oil layer and cause peaking oil emissions.
    Publicationtype: Journal Article
      84  24
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    Item type:Publication, Access status: without files ,
    Investigation of oil emission mechanisms in a marine medium-speed dual-fuel engine
    (2022-09)
    Hochfellner, Baptiste
    ;
    Wirz, Friedrich
    ;
    Pryymak, Konstantin
    ;
    Preuß, Ann-Christin
    ;
    Matz, Gerhard
    Pilot-ignition otto marine engines are known for greatly reduced emissions of air pollutants (sulphur, nitrogen oxide, particulates) compared to marine diesel engines. However, lubricating oil emissions still are about one order of magnitude higher than in land-based systems. To identify reduction potentials, a better understanding of oil emission mechanisms has to be gained. For this purpose, mass spectrometric oil emission measurements and fluorescence lubricating film thickness measurements were performed on a medium-speed marine engine. With the fluorescence measuring system, the varying lubricating oil film on the cylinder wall can be visualised and analysed in sub-crank-angle resolution. This enables ring rotation detection and investigations show a connection between ring rotation and cylinder liner temperature distribution. Aligning ring gaps allow blow-by to happen. This and other high intensity events such as engine knock, load shedding or the transition from diesel-mode to gas-mode, heavily disturb the oil layer and cause peaking oil emissions.
    Publicationtype: Conference Paper
      50
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    Item type:Publication, Access status: with files ,
    LED-induced-fluorescence measurements at an LNG dual-fuel marine engine test bed : the test bed, the measurement technology, findings from the measurement results
    (2022-05-06)
    Hochfellner, Baptiste
    LNG operation in so-called dual-fuel engines is viewed as an environmentally friendly alternative in shipping. In these engines a natural-gas/air mixture is ignited via Diesel fuel pilot injection. This is a combination of the Diesel and the Otto processes. Classic Diesel operation is generally still possible. The current limits for nitrogen oxide emissions and sulfur can be met with these systems without exhaust gas purification even in Emission Control Areas. Dual-fuel engines also have an advantage over classic Diesel engines in terms of particulate-matter emissions, but so far they have not reached the values of Otto engines. Since almost no soot occurs in dual-fuel operation, the majority of particulate-matter emissions originate from lubricating oil. This oil is intended to minimize mechanical wear as well as chemical wear in the cylinder. Due to the sulfur content in many Diesel fuels, sulfuric acids are formed during combustion, which are neutralized by alcalic additives in the lubricating oil. With the 2020 sulphur-cap of the IMO the necessity of acid neutralization is reduced considerably. This allows adjustments of the lubrication system and thus a reduction of particulate-matter emissions. A positive side effect is the associated economic benefit of reduced lube oil consumption. The Department of Marine Engineering at TUHH operates a medium-speed LNG dual-fuel marine engine test bed. With LED-induced fluorescence, a technology is used in the cylinder liner that has not yet been applied in the marine engine sector. A fluorescent agent added to the lubricating oil is excited via an LED and the intensity of the resulting radiation is measured. This allows conclusions to be drawn about the amount of lubricating oil present at the measuring points. In addition, emitted aerosols and oil masses are recorded immediately after ejection from the cylinder and analyzed in terms of size, number and mass of particles. The particular challenge is to combine these two very different measuring methods in order to be able to draw conclusions about the underlying physical and chemical mechanisms. The goal is a deeper understanding of these operating point-dependent mechanisms of particulate-matter emission generation in order to be able to find measures to control these emissions.
    Publicationtype: Conference Presentation
      71  46
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    Item type:Publication, Access status: without files ,
    Lubrication large bore engines I
    (Forschungsvereinigung Verbrennungskraftmaschinen e.V., 2021-03)
    Hochfellner, Baptiste
    ;
    Schlemmer-Kelling, Udo
    ;
    Preuß, Ann-Christin
    ;
    Pryymak, Konstantin
    This report represents phase I of a research cluster regarding the scientific deepening of the compre-hension about particulate matter (PM) emission formation traceable to lubricating oil consumption in medium-speed engines. These ICEs are mainly operated on-board ships and in stationary power plants, environments that are fundamentally different from typical land vehicle use. On one hand PM-emission limits do not exist in the maritime sector. On the other hand, service life, reparability, reliabil-ity, efficiency and corrosive wear play decisive roles. Apart from the operating costs, there is there-fore no incentive to reduce the lubricating oil consumption. Consequently, this is about an order of magnitude higher than with their counterparts. However, the increasing interest in new alternative fuels and combustion processes, as well as new and regularly tightened emission limits, point to the need to investigate the undoubted potential for lubricating oil consumption reduction. In the course of this project three research institutes share knowledge and appliances. Two medium speed marine engine test beds at Hamburg University of Technology (ASM) and Flensburg University of Applied Sciences (INMT) have been accompanied by measurements from Institute for Analytical Measurement Technology Hamburg eV (IAM). Phenomena and correlations of the tribological system in the area of the piston group were being investigated. To analyze the oil supply in the combustion chamber, which contributes to emissions, a combination of exhaust gas analysis and optical film thickness measurement was applied. The objective in terms of measuring technology in this project was to validate the measurement capability with these systems on the large bore engines. The development of the measurement systems was accompanied by adjustments to the existing hardware and the development and implementation of new hardware at both engine test beds. At ASM a cylinder liner for the dual-fuel test bed has been designed. It comes with a new form factor, reduced dead volume and is equipped with a modern honing structure. It also is ready for optical oil film thickness measurements. At INMT the whole piston group was updated. The new Mid Stop cylin-der liner design with Anti-Polishing-Rings and modern honing structure is paired with an improved piston ring geometry. In terms of the exhaust gas analysis a mass spectrometer with fast direct inlet system for quantifying oil emission and an aerosol spectrometer for quantifying aerosol particle emission were used. The high particulate load due to soot formation in diesel operation, combined with the much slower set-tling times of large bore engines compared to passenger car engines, required inlet contamination prevention. Measurements were successfully carried out with both systems on the engine at ASM. The measure-ment capability of the aerosol measurement technology was also demonstrated at INMT. The oil emission measurements at INMT show oil emission effects that do not correspond to those of other engines. It is necessary to further modify the measurement method in order to successfully quantify the oil emission. This will be implemented in the follow-up project by tracing the oil with PAHs. The determination of the oil film thickness on the cylinder liner was carried out using the in-house de-veloped, compact and cost-effective LED measuring system based on the fluorescence principle. Initial measurement results obtained at ASM have shown the potential and limitations of the approach. Important steps in this process are interpretation of the measurement results of the oil film thickness-es at different positions on the cylinder liner as well as their correlation with other relevant measurements.
    Publicationtype: Conference Paper
      94
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    Item type:Publication, Access status: without files ,
    Lubrication large bore engines
    (Forschungsvereinigung Verbrennungskraftmaschinen e.V., 2019-09)
    Hochfellner, Baptiste
    ;
    Wirz, Friedrich
    ;
    Preuß, Ann-Christin
    ;
    Pryymak, Konstantin
    ;
    Matz, Gerhard
    Publicationtype: Conference Poster not in Proceedings
      97
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    Item type:Publication, Access status: without files ,
    Lubrication large bore engines
    (Forschungsvereinigung Verbrennungskraftmaschinen e.V., 2019-03)
    Hochfellner, Baptiste
    ;
    Wirz, Friedrich
    ;
    Preuß, Ann-Christin
    ;
    Pryymak, Konstantin
    ;
    Matz, Gerhard
    The three main air pollutants produced by marine traffic are sulphur oxides, nitrogen oxides and particulate matter (PM). Due to the fact that marine traffic near shores and even in urban areas is on the rise, while on the other hand air quality is a major political and social concern, special account needs to be taken of the environmental impact of ships operating in these regions. While strict restrictions for the first two mentioned pollutants exist, there are currently none for PM emissions in shipping. Since it is only a matter of time before threshold values will be set, the gaining of knowledge in the field of PM is of exceptional importance. The target of the project is an evaluation of measures that are expected to reduce the lubricating oil-originated PM emissions with respect to their results and impact on engine operation. Additional goals are the classification of PM emissions in medium speed engines and to describe the correlation between these emissions and the lubricating oil film thickness.
    Publicationtype: Conference Poster not in Proceedings
      46
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    Item type:Publication, Access status: without files ,
    Schmierungskonzept Großmotor
    (2018)
    Wallin, Baptiste
    Der Schmierölverbrauch von Großmotoren liegt nach derzeitigem Stand der Technik mit etwa 0,6 g/kWh bis zu einer Größenordnung über dem Schmierölverbrauch von kleineren hochbelasteten Motoren, die beispielsweise im LKW-Bereich eingesetzt werden. Der Großteil des Schmierölverbrauchs von Verbrennungsmotoren entsteht an der Kolbenring-Laufbuchsen-Paarung. Es wird angenommen, dass ein erhebliches Potential besteht, den Schmierölverbrauch von Großmotoren zu reduzieren. Um dieses zu heben, bedarf es der genauen Kenntnis der Phänomene und Zusammenhänge bezüglich der Tribologie und der Ölverbrauchsprozesse in der Kolbengruppe. Im Rahmen der an der Arbeitsgruppe Schiffsmaschinenbau durch Eigenmittel der Forschungsvereinigung Verbrennungskraftmaschinen finanzierten Studie „Schmierungskonzept Großmotor“ werden Unterschiede zwischen Viertakt-Großmotoren und Motoren aus dem LKW-Bereich analysiert sowie die Stellgrößen und mögliche Maßnahmen zur Beeinflussung des Schmierölverbrauchs identifiziert und hinsichtlich ihres Einflusses bewertet. Außerdem wird in Hinblick auf ein geplantes Anschlussvorhaben eine Versuchsmatrix erstellt, der Materialeinsatz abgeschätzt und geeignete Messtechnik ermittelt.
    Publicationtype: Technical Report
      325