Seppo Mikkonen

Hydrotreated Vegetable Oil (HVO) as a Renewable Diesel Fuel: Trade-off between NOx, Particulate Emission, and Fuel Consumption of a Heavy Duty Engine

Hydrotreating of vegetable oils or animal fats is an alternative process to esterification for producing biobased diesel fuels. Hydrotreated products are also called renewable diesel fuels. Hydrotreated vegetable oils (HVO) do not have the detrimental effects of ester-type biodiesel fuels, like increased NO x emission, deposit formation, storage stability problems, more rapid aging of engine oil or poor cold properties. HVOs are straight chain paraffinic hydrocarbons that are free of aromatics, oxygen and sulfur and have high cetane numbers. In this paper, NO x ‐ particulate emission trade-off and NO x ‐ fuel consumption trade-off are studied using different fuel injection timings in a turbocharged charge air cooled common rail heavy duty diesel engine. Tested fuels were sulfur free diesel fuel, neat HVO, and a 30% HVO + 70% diesel fuel blend. The study shows that there is potential for optimizing engine settings together with enhanced fuel composition. HVO could be used in optimized low emission diesel power trains in captive fleet applications like city buses, indoor fork-lift trucks, or mine vehicles.

The Effect of Diesel Fuel Reformulation on the Exhaust Measured by Ames Mutagenicity and DNA AddUcts

In this study we compared two reformulated and one standard European Diesel fuel between particulate soluble organic fraction of PAH, mutagenic activity, and DNA adduct formation. Adducts were analyzed in vitro calf thymus DNA with and without the metabolic activation system and measured by 32 P-postlabeling method. PAH-DNA adduct formation and mutagenicity by Ames test were compared. Both biological tests showed that reformulation decreased genotoxic PAH compounds in diesel particle emission.

Trace Element Determination in Diesel Particulates by Total-Reflection X-Ray Fluorescence Analysis

Abstract. Particulate matter of Diesel emissions collected from diluted exhaust during standard test runs with two Diesel fuels of different sulfur content was analysed by total-reflection X-ray fluorescence (TXRF). The trace elements determined were S, Ca, Cr, Mn, Fe, Ni, Cu, Zn and Pb. Additionally, some filter materials were tested with respect to their applicability for sample collection. Quartz fibre filters were found to be most suitable, both from a technical and a chemical point of view. A clear reduction of total particulate emissions during the whole test was observed when the fuel with very low sulfur content was used. In addition, it was found that the wear metal content of particulate matter emitted by a cold engine was higher than that observed during normal engine working temperature.

DNA Adducts Derived from Diesel Emissions - Assessment of Genotoxic Potency in Vitro and Human Exposure Monitoring

Abstract Diesel particle extracts, which originated from three different diesel fuels, were used to study the activation of polycyclic aromatic hydrocarbons (PAHs). DNA adducts were analyzed in vitro calf thymus, human skin tissue culture and in lymphocytes isolated from diesel exposed workers. Direct-acting mutagens (e.g. nitro-PAHs) measured by Ames test were compared with DNA adducts formed in vitro by nitroreductive xanthine oxide enzyme. PAH-DNA adducts were analyzed by 32P-postlabeling, and when characterizing adducts from skin DNA, a solid-phase micro extraction (SPME) method was developed for sample preparation before HPLC analysis. A good accordance between mutagenicity and DNA adducts showed that the three extracts contain higher amounts of direct-acting PAHs than the PAHs needing S9 activation. Skin DNA adducts demonstrated two-fold differences between the tissue cultures. 32P-postlabeling and HPLC analysis did not confirm the identity of skin DNA adducts with the BPDE-DNA standard. The pilot study on 13 diesd exposed bus garage and waste collection workers showed low levels of PAH exposure (<50 ng/m3) and lymphocyte PAH-DNA adducts less than 2 adducts/108 nucleotides.

Intake valve sticking in some carburetor engines

Intake valve sticking, created by the accumulation of deposits on the valve stems, caused cold starting problems and engine failures at low temperatures (below + 5/sup 0/C). Sticking was promoted by the high olefin content in gasoline (over 25% FIA). Sticking did not occur if gasoline contained no detergent additives. Some additives even led to sticking while some solved the problem. Engine oils containing polymeric additives promoted sticking. Clearances of intake valve stems and stem seals were probably factors affecting sticking. Tests were made using cars on the road on an urban driving cycle.