Digital vibroacoustic signal processing for combustions in heavy-duty diesel engine for operational and environmental machine efficiency

The paper concerns the assessment of a combustion process correctness in direct injection compression-ignition engine of a HDV vehicle. The method of such diagnoses is based on the vibration acceleration signal and its digital processing. Identification of a combustion process runs and detection of some failures taking place in the combustion chamber during engine working cycles are important in the point of view of environmental and operational engines characteristics. That is why the authors considered this scientific problem, trying to show the possibility of the precise diagnosis of combustion process regarding with the requirements of OBD regulations. The method of misfire identification for a compression-ignition engine, based on results of parameterizations of a time-frequency a(t,f) map of an engine vibration signal taken from engine heads, was used in the diagnostic process. Parameterization of a(t,f) map gives measures covariable with misfire in a cylinder of an internal combustion engine and obtained point measures can be used as diagnostic parameters for combustion process control and its diagnostics. Reliability of a method for combustion process assessment was checked for research conducted in stationary and real engine operation conditions

Analysis of vibroacoustic estimators for a heavy-duty diesel engine used in sea transport in the aspect of diagnostics of its environmental impact

The paper describes the impact of a marine engine operation on selected vibroacoustic quantity estimators and their characteristics made in different signal domains. The authors focused on the assessment of the combustion process diagnostic for the engine operating characteristics to obtain information on its functional relations and its nature determined by changes in the main structural and operational point measures, in a powertrain of a non-road means of sea transport. In the empirical research, the vibration, acoustic signal generation and its propagation have been selected to obtain quantitative measures of an engine diagnostic assessment. The authors have confirmed that the considered vibroacoustic estimators and their specified characteristics can be useful for a continuous engine assessment in a vehicle during its normal operation, which gives additional tools to perform more accurate diagnostics under real stationary and non-stationary operating conditions. Furthermore, it makes it possible to identify malfunctions in regular operation of the means of transport, which can be also helpful in the identification of their sources. All such factors and the obtained analyses are in strict correlation with the present and future requirements of the international and domestic regulations for means of transport fitted with combustion engines

Analysis of vibroacoustic estimators for a heavy-duty diesel engine used in sea transport in the aspect of diagnostics of its environmental impact

The paper describes the impact of a marine engine operation on selected vibroacoustic quantity estimators and their characteristics made in different signal domains. The authors focused on the assessment of the combustion process diagnostic for the engine operating characteristics to obtain information on its functional relations and its nature determined by changes in the main structural and operational point measures, in a powertrain of a non-road means of sea transport. In the empirical research, the vibration, acoustic signal generation and its propagation have been selected to obtain quantitative measures of an engine diagnostic assessment. The authors have confirmed that the considered vibroacoustic estimators and their specified characteristics can be useful for a continuous engine assessment in a vehicle during its normal operation, which gives additional tools to perform more accurate diagnostics under real stationary and non-stationary operating conditions. Furthermore, it makes it possible to identify malfunctions in regular operation of the means of transport, which can be also helpful in the identification of their sources. All such factors and the obtained analyses are in strict correlation with the present and future requirements of the international and domestic regulations for means of transport fitted with combustion engines

Tests and simulations referring to application the vibroacoustic methods for diagnosing the misfiring in the engines with the self-ignition of the diesel locomotives

Niniejszy artykuł dotyczy możliwości zastosowania metody oceny procesu spalania i jego braku w silnikach spalinowych pojazdów szynowych, bazującej na wykorzystaniu parametrów sygnału drganiowego. Zamieszczono w nim wyniki badań silnika spalinowego lokomotywy w warunkach jej eksploatacji. Wykazano możliwość zastosowania estymat sygnału drganiowego do oceny braku spalania w silniku spalinowym oraz dużą wiarygodność diagnostyki procesu spalania za pomocą powyższej metodyThe present article refers to the possibility of application the assessment method of the combustion process and its lack in the diesel engines of the rail vehicles, basing on using the parameters of the vibration signal. The results of tests of the diesel engine of the locomotive in the conditions of its operation are placed in it. It is shown the possibility of application the estimates of the vibration signal for assessment of the lack of combustion in the diesel engine and the big credibility of the diagnosis of the combustion process by means of the above mentioned method

Methodological basis of road acoustic researches

Transport is one of the most burdensome negative sources affecting the natural environment. Long-term exposure of the body to exhaust pollution can cause health problems and, in the worst case, even lead to death. In addition to exhaust emissions, traffic noise is another equally important issue. Due to its nature, variability over time or the design diversity of vehicles in the traffic flow, it is a phenomenon difficult to define. Like exhaust pollution, it affects people's health and quality of life. In addition to its direct impact on the human physical system, it can also cause psychosomatic disorders, which is why a detailed analysis of road noise taking into account the real operation of the vehicle is so important. The paper presents the basic concepts related to the problem of traffic noise in the world, determines the sources of noise in vehicles and the methodology of conducting acoustic road tests. At the final stage of the scientific paper, methods of reducing excessive noise levels in large urban agglomerations were also presented, and the effectiveness of using noise barriers on selected parts of the city road network using proprietary acoustic tests was assessed

Analysis of vibroacoustic estimators for a heavy-duty diesel engine used in sea transport in the aspect of diagnostics of its environmental impact

The paper describes the impact of a marine engine operation on selected vibroacoustic quantity estimators and their characteristics made in different signal domains. The authors focused on the assessment of the combustion process diagnostic for the engine operating characteristics to obtain information on its functional relations and its nature determined by changes in the main structural and operational point measures, in a powertrain of a non-road means of sea transport. In the empirical research, the vibration, acoustic signal generation and its propagation have been selected to obtain quantitative measures of an engine diagnostic assessment. The authors have confirmed that the considered vibroacoustic estimators and their specified characteristics can be useful for a continuous engine assessment in a vehicle during its normal operation, which gives additional tools to perform more accurate diagnostics under real stationary and non-stationary operating conditions. Furthermore, it makes it possible to identify malfunctions in regular operation of the means of transport, which can be also helpful in the identification of their sources. All such factors and the obtained analyses are in strict correlation with the present and future requirements of the international and domestic regulations for means of transport fitted with combustion engines

Exhaust Emissions from a Hybrid City Bus Fuelled by Conventional and Oxygenated Fuel

City buses are one of the main means of public transport in cities. As they move in a limited and densely populated area and are intensively exploited, it is particularly important that they are environmentally friendly. There are many ways to reduce emissions from city buses, including the use of hybrid propulsion. Another way is to use low-emission fuels. This article presents the results of the emission tests of an 18 m articulated city bus with a serial hybrid drive fuelled comparatively by conventional diesel fuel and oxygenated fuel containing 10% v/v of triethylene glycol dimethyl ether (TEGDME). The emission tests were carried out during the actual operation of the bus on a route in Poznań (Poland) and over the SORT cycles. The obtained test results were compared also with the results obtained for a conventional bus. The reduction in emissions of some exhaust components was found when the hybrid bus was fuelled with oxygenated fuel during its actual operation on the bus route. There was a reduction in CO emissions by ~50% and NOx emissions by ~10%. Almost identical levels of PM and HC emissions and smoke opacity were observed for both fuels. In the SORT cycles, the differences in the emissions obtained for both types of fuel were small. In general, for the hybrid bus, a lower influence of oxygenated fuel on emissions was recorded than for the conventional bus

Can Low-Level Ionizing Radiation Do Us Any Harm?

The current system of radiological protection relies on the linear no-threshold (LNT) hypothesis of cancer risk due to humans being exposed to ionizing radiation (IR). Under this tenet, effects of low doses (i.e. of those not exceeding 100 mGy or 0.1 mGy/min. of X- or γ-rays for acute and chronic exposures, respectively) are evaluated by downward linear extrapolation from regions of higher doses and dose rates where harmful effects are actually observed. However, evidence accumulated over many years clearly indicates that exposure of humans to low doses of radiation does not cause any harm and often promotes health. In this review, we discuss results of some epidemiological analyses, clinical trials and controlled experimental animal studies. Epidemiological data indicate the presence of a threshold and departure from linearity at the lowest dose ranges. Experimental studies clearly demonstrate the qualitative difference between biological mechanisms and effects at low and at higher doses of IR. We also discuss the genesis and the likely reasons for the persistence of the LNT tenet, despite its scientific implausibility and deleterious social consequences. It is high time to replace the LNT paradigm by a scientifically based dose-effect relationship where realistic quantitative hormetic or threshold models are exploited

Influence of Dimethyl Ether Combustion in the Compression-Ignition Engine on the Peak and Effective Measures of the Vibroacoustic Process and Toxic Compounds Emission

The scientific paper conducted empirical studies related to the effectiveness of the use of dimethyl ether as an additive to diesel fuel and its impact on the efficiency of the mixture creation and combustion process. The measure of the above quality was the observation and parametric assessment of the then generated vibroacoustic processes, the relations of which were assessed using the peak and effective value of vibration accelerations, and also assessment of toxic exhaust gas components. The transformation of the main process into its vibroacoustic and emission representations allowed for the construction of mathematical relations between them, expressed in a specific engine operating space, and a vector of tribological parameters, expressing specific friction changes occurring in the critical kinematic pairs of the combustion and mixture formation area. The tests were carried out on a single-cylinder research engine with direct fuel injection, in stationary conditions with a time-invariant control vector. As part of the procedures, a constant and optimal value of thermodynamic parameters defining the thermal state of the engine was maintained, minimizing external forces and disturbances that could affect the active value of the measurement signal. The research results are empirical vibroacoustic and emission characteristics for various signal domains and their parameterization supplemented with a detailed analysis of the results, developed vibroacoustic and emission mathematical models depending on the operating parameters, type of fuel and combustible mixture formation variables, supplemented with an assessment of their degree of mapping to the dynamic source process. The dimethyl ether application resulted in a emission reduction by the coefficient: 24.3–57.8 (hydrocarbons), 1.03–1.24 (carbon monoxide), and an increase in nitrogen oxides in the range of 1.01–1.08. The use of dimethyl ether as a base fuel component has a positive effect on reducing the peak value of vibration accelerations in the range of 16–28%, and the root mean square in the range of 14–65%