Vehicle nanoparticle emissions under transient driving conditions

Real-world driving consist mostly of transients, where the engine parameters are constantly changing. In emission regulation this has been partially considered by including transient driving cycles in emission standards. However, specific particle emissions data for detailed driving conditions have remained limited. This thesis covers results of transient exhaust particle emissions, including both diesel and gasoline engines. The experiments were performed in laboratories and on the road. The focus was always on the real-world particle emissions. During transient cycles both heavy-duty (HD) diesel engines and light-duty (LD) gasoline vehicles produced elevated soot particle concentrations during accelerations. For instance, in on-road experiment of a LD gasoline vehicle, the exhaust plume particle concentrations at steady speeds were at clean ambient levels, but during accelerations concentrations were 10-50 times the background level. For gasoline vehicles the soot particle size distributions were bi-modal in nature. Currently neither LD gasoline nor nonroad HD diesel engines necessarily need to employ particle filtration in the exhaust system in order to meet the demands of the relevant legislation. Sulfur originating in the fuel or lubricant oil can be stored inside catalysts, and later be released, forming semivolatile nucleation mode (NM) particles when temperature rises. This behavior was detected for LD and HD engines in the engine laboratory, for a HD vehicle on the road and in a simplified measurement setup in an aerosol laboratory. The aerosol laboratory test indicated that the NM formation does not necessarily require hydrocarbons or sulfated hydrocarbons; particles are electrically neutral and evaporate when they undergo thermal treatment. While sulfur is released from the catalysts, the HD road engine study indicated that the increased NM particle emission is not explained by the concentration of gaseous sulfuric acid. The sulfur storage and release depends greatly on the driving history, also due to this NM particle emissions seem plausible, even with low sulfur fuels. With catalytic particle filters, the amount of soot is reduced, promoting semivolatile NM particle emissions. An unexpected observation was made that some engines produce nanoparticles containing lubricant oil derived metals during driving while not fueled. Exhaust particles were observed during engine braking events for a HD truck and LD gasoline vehicles. For the truck and gasoline vehicles, the engine braking related particles contributed up to 20-30% and 3-30% of the total number emissions, respectively. These particle emissions can be a reality for all vehicle types not using particle filtration, including the latest technology vehicles. In particle filters, engine braking related particles can affect the ash accumulation and transport mechanisms

Particle number, mass, and black carbon emissions from fuel-operated auxiliary heaters in real vehicle use

Fuel-operated auxiliary heaters (AHs) are frequent solutions to heat the vehicle engines and cabins in cold areas. Particulate exhaust emissions of AHs are unregulated; therefore, their contribution to local air quality and thus human health and even the global emissions budget is unknown. Experiments for studying the AH-originated emissions were performed under Finnish winter conditions mimicking real-world use for six selected vehicles with original AHs installed, including both gasoline- and diesel-powered heaters. We present quantitative results of particle number emissions down to 1.3 nm, particle size distributions, particulate mass, and black carbon, and compare to gaseous emissions. The start-up and shutdown phases showed the highest particle peaks, while the particle concentrations were stable between these. The mean particle number, mass and BC emission factors were found to be as high as 590 × 1012 kgfuel−1, 33 mg kgfuel−1 and mg 18 kgfuel−1 for gasoline-operated heaters and 560 × 1012 kgfuel−1, 20 mg kgfuel−1 and 12 mg kgfuel−1 for diesel-operated heaters. Comparing total number of particles larger than 23 nm emitted during vehicle preheating with AH to vehicle tailpipe emissions during drive shows that a typical heating cycle emits an equal number of particles to drive dozens or even thousands of kilometers.publishedVersionPeer reviewe

Nonvolatile ultrafine particles observed to form trimodal size distributions in non-road diesel engine exhaust

Some recent findings regarding the negative health effects of particulate matter increase the relevance of the detailed characteristics of particulate emissions from different sources and especially the nonvolatile fraction of particles. In this study, the nonvolatile fraction of ultrafine particulate emissions from a non-road diesel engine was studied. The measurements were carried out in an engine laboratory and the exhaust sample was taken from the engine-out location with various steady state driving modes. Four different fuels, including fossil fuel, soybean methyl ester (SME), rapeseed methyl ester (RME), and renewable paraffinic diesel (RPD), were used. In the sampling system, the sample was diluted and led through a thermodenuder removing the volatile fraction of particles. The measured particle size distributions of nonvolatile particles were found to be trimodal. Based on the size distribution data as well as the morphology and elemental composition of particles in transmission electron microscopy (TEM) samples, we were able to draw conclusions from the most probable origin of the different particle modes, and the modes were named accordingly. From larger to smaller in particle size, the modes were a soot mode, lubricating oil originated core (LC) mode, and a fuel originated core (FC) mode. All of these three modes were detected with every driving mode, but differences were seen, for example, between different fuels. In addition, a trade-off was observed in the concentrations of the LC mode and the soot mode as a function of the engine torque.© 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License (http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed, or built upon in any way.fi=vertaisarvioitu|en=peerReviewed

Characterization of laboratory and real driving emissions of individual Euro 6 light-duty vehicles – Fresh particles and secondary aerosol formation

Emissions from passenger cars are one of major sources that deteriorate urban air quality. This study presents characterization of real-drive emissions from three Euro 6 emission level passenger cars (two gasoline and one diesel) in terms of fresh particles and secondary aerosol formation. The gasoline vehicles were also characterized by chassis dynamometer studies. In the real-drive study, the particle number emissions during regular driving were 1.1–12.7 times greater than observed in the laboratory tests (4.8 times greater on average), which may be caused by more effective nucleation process when diluted by real polluted and humid ambient air. However, the emission factors measured in laboratory were still much higher than the regulatory value of 6 × 10^(11) particles km^(−1). The higher emission factors measured here result probably from the fact that the regulatory limit considers only non-volatile particles larger than 23 nm, whereas here, all particles (also volatile) larger than 3 nm were measured. Secondary aerosol formation potential was the highest after a vehicle cold start when most of the secondary mass was organics. After the cold start, the relative contributions of ammonium, sulfate and nitrate increased. Using a novel approach to study secondary aerosol formation under real-drive conditions with the chase method resulted mostly in emission factors below detection limit, which was not in disagreement with the laboratory findings

Engine preheating under real-world subfreezing conditions provides less than expected benefits to vehicle fuel economy and emission reduction for light-duty vehicles

Six light-duty vehicles, both gasoline- and diesel-fueled, were driven a prescribed 13.8 km route in a real-world low-traffic environment under Finnish subfreezing winter conditions (−28. −10 °C). Cold starts, hot starts, and starts with different preheating strategies were used. Fuel consumption and emissions of particles and nitrogen oxides (NOx) were examined by a chasing method with a mobile laboratory. Both electric preheaters (0.3–1.2 kW) and fuel-operated auxiliary heaters (5 kW) were used in the experiments where a cold engine was preheated before starting. While most vehicles showed potential for reducing fuel consumption and emissions of particles (PM), black carbon (BC), and NOx during hot starts compared to subfreezing-cold starts, the benefits of preheating were relatively small and limited to only a few vehicles. The fuel consumption for the 13.8 km drive decreased less than 4% with one gasoline vehicle and one diesel vehicle by preheating. These two vehicles are both equipped with a fuel-operated auxiliary heater, and taking the fuel consumption of the heater during preheating into account leads to about 30% higher total fuel consumption, canceling the preheating benefit out. These two vehicles also showed the largest reductions in PM, BC, and NOx emissions achieved with preheating, e.g., the PM emission reductions being 72% (the gasoline vehicle) and 24% (the diesel vehicle). Whereas the NOx emission reduction for this gasoline vehicle was 41% when considering only the drive, it decreases to 15% when the NOx emissions from the auxiliary heater during preheating are also taken into account. High particle number (PN) emissions from all vehicles and NOx emissions from the diesel vehicles were detected. The PN emissions of particles larger than 23 nm were up to 2 orders of magnitude higher and the NOx emissions up to a factor of 21 higher than the corresponding limits in the European regulations for type-approval of new vehicles. The PN emissions did not depend on the start types; thus, no benefits to reduce them with preheating were detected. The limit-exceeding PN emissions are partially explained with the used measurement method for PN taking both nonvolatile and semivolatile particles into account, whereas the regulations take only the nonvolatile particles into account. The PM emissions were also observed to consist mostly of semivolatile material in most of the cases, organics being the main component of the semivolatile material.Peer reviewe

Physical activity and sedentary behaviour in relation to cardiometabolic risk in children: cross-sectional findings from the Physical Activity and Nutrition in Children (PANIC) Study

BACKGROUND: Lower levels of physical activity (PA) and sedentary behaviour (SB) have been associated with increased cardiometabolic risk among children. However, little is known about the independent and combined associations of PA and SB as well as different types of these behaviours with cardiometabolic risk in children. We therefore investigated these relationships among children. METHODS: The subjects were a population sample of 468 children 6–8 years of age. PA and SB were assessed by a questionnaire administered by parents and validated by a monitor combining heart rate and accelerometry measurements. We assessed body fat percentage, waist circumference, blood glucose, serum insulin, plasma lipids and lipoproteins and blood pressure and calculated a cardiometabolic risk score using population-specific Z-scores and a formula waist circumference + insulin + glucose + triglycerides - HDL cholesterol + mean of systolic and diastolic blood pressure. We analysed data using multivariate linear regression models. RESULTS: Total PA was inversely associated with the cardiometabolic risk score (β = -0.135, p = 0.004), body fat percentage (β = -0.155, p < 0.001), insulin (β = -0.099, p = 0.034), triglycerides (β = -0.166, p < 0.001), VLDL triglycerides (β = -0.230, p < 0.001), VLDL cholesterol (β = -0.168, p = 0.001), LDL cholesterol (β = -0.094, p = 0.046) and HDL triglycerides (β = -0.149, p = 0.004) and directly related to HDL cholesterol (β = 0.144, p = 0.002) adjusted for age and gender. Unstructured PA was inversely associated with the cardiometabolic risk score (β = -0.123, p = 0.010), body fat percentage (β = -0.099, p = 0.027), insulin (β = -0.108, p = 0.021), triglycerides (β = -0.144, p = 0.002), VLDL triglycerides (β = -0.233, p < 0.001) and VLDL cholesterol (β = -0.199, p < 0.001) and directly related to HDL cholesterol (β = 0.126, p = 0.008). Watching TV and videos was directly related to the cardiometabolic risk score (β = 0.135, p = 0.003), body fat percentage (β = 0.090, p = 0.039), waist circumference (β = 0.097, p = 0.033) and systolic blood pressure (β = 0.096, p = 0.039). Resting was directly associated with the cardiometabolic risk score (β = 0.092, p = 0.049), triglycerides (β = 0.131, p = 0.005), VLDL triglycerides (β = 0.134, p = 0.009), VLDL cholesterol (β = 0.147, p = 0.004) and LDL cholesterol (β = 0.105, p = 0.023). Other types of PA and SB had less consistent associations with cardiometabolic risk factors. CONCLUSIONS: The results of our study emphasise increasing total and unstructured PA and decreasing watching TV and videos and other sedentary behaviours to reduce cardiometabolic risk among children. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01803776

STUDI TEKNO-EKONOMI MESIN PENGIRIS BAWANG MERAH (Allium cepa var ascalonicum (L) Back) BUATAN UPTD BMP-TPH BUKITTINGGI

STUDI TEKNO-EKONOMI MESIN PENGIRIS BAWANG MERAH(Allium cepa ascalonicum (L) Back) BUATAN UPTD BMP-TPH BUKITTINGGI Fitri Amelia, Santosa, Andasuryani ABSTRAK Tanaman bawang merah termasuk tanaman holtikultura dimanfaatkan sebagai bahan makanan, penambah cita rasa dan nilai estetika pada menu makanan. Pengirisan merupakan satu cara pengolahan dan penangganan bawang merah yang sering dilakukan. Penelitian bertujuan melakukan studi tekno-ekonomi mesin pengiris bawang merah buatan Unit Pelayanan Teknis Daerah Balai Mekanisasi Pertanian Tanaman Pangan Hortikultura Bukittinggi, yang dilaksanakan pada bulan Juni sampai Agustus 2018. Bawang merah yang digunakan adalah varietas bima. Metode yang dilakukan pada pengamatan ini dengan cara mengganti ukuran puli, sehingga RPM akan berubah. RPM yang digunakan pada pengamatan ini sebesar 1114, 1300 dan 1560. Masing-masing RPM dilakukan sebanyak lima kali ulangan. Berdasarkan hasil pengujian mesin bahwa RPM yang lebih cocok digunakan adalah 1560 karena kapasitas kerja lebih tinggi yaitu sebesar 96,93 kg/jam, energi spesifik lebih rendah yaitu sebesar 0,0038687 kW.jam/kg dan biaya pokok yang lebih rendah yaitu Rp 1164,38,-/kg. Kata kunci – Bawang Merah, Pengirisan, RPM, Studi Tekn