Визначення вимог та поетапна розробка алгоритму діагностичної моделі газотурбінного двигуна ТВ3-117В

Investigations on the Effect of Waste Fried Oil Methyl Ester Blends and Load on Performance and Smoke Opacity of Diesel Engine Using Response Surface Methodology

Investigation of the effects of gasoline and CNG fuels on a dual sequential ignition engine at low and high load conditions

The by-pass system of exhaust gas for the engine 6L20 Wartsila has been observed. The requirements of Annex VI MARPOL towards nitrogen oxide concentration in ship engine exhaust gases have been provided. The purpose of research was the determination of diesel 6L20 Wartsila by-pass exhaust gases optimum volume – at this the nitrogen oxide minimal concentration in exhaust gases is assured, the minimal increase (comparing with operation mode without by-pass) – specific effective fuel consumption, supporting of necessary thermal factor diapason of engine cylinders. The research was performed for the exhaust gas by-pass diapason 0…10 % with engine load diapason 0.55…0.85 % from nominal power. Upon experimental results it has been stated that the exhaust gas by-pass usage favors the ecological parameters of ships engine operation modes – by this at the range of exploitation load 0.55…0.85 % from nominal power the nitrogen oxide concentration in exhaust gas is decreased to 1.32….12.97 %. The exhaust gas by-pass impairs the combustion process and favors the increasing of specific effective fuel consumption and increasing the temperature of exhaust gases. The exhaust gas by-pass system effectiveness assessment should be performed by complex estimation of the following engine operation parameters: the nitrogen oxide concentration in exhaust gas, increasing of specific effective fuel consumption(SFOC), the exhaust gas temperature. As optimal degree of exhaust gas by-pass value when the maximum decrease of nitrogen oxide emission at minimal increase of fuel consumption and simultaneous engine thermal factor handling has to be considered.

Hybrid MultiGene Genetic Programming - Artificial neural networks approach for dynamic performance prediction of an aeroengine

The article presents a diagnostic and reliability model of an internal combustion engine that allows to assess the reliability status of the engine’s systems for a two-state model of operation and maintenance: functional – failed. The proposed diagnostic model is a qualitative-quantitative probabilistic model combining the reliability states of the engine systems with the values of the vibroacoustic diagnostic signal parameters. The conducted diagnostic and reliability experiments and simulation tests showed that based on the developed diagnostic and reliability model, it is possible to determine the reliability states of the engine.

Emission characteristics of a diesel engine with an electrically heated catalyst under cold start conditions

Purpose. Ensuring reliable operation of heating heat-generating devices with recirculation and exhaust gas heat recovery. Methodology. The normative methods of thermal calculation for surface heat exchange devices and the software according to the requirements of regulatory methods for this type of equipment for processing the results of our own experimental studies on heat exchange during deep cooling of combustion products of gas-consuming boilers were used. Findings. Calculation studies on the thermal operation modes during the heating period under the conditions of recirculation and heat recovery of flue gases of gas-fired water-heating boiler plants not equipped with air heaters were carried out. The main characteristics were determined of the thermal and humidity operation state for the air-supply ducts of these installations under the conditions of recirculation of flue gases’ part into the blown air. Regularities of temperature and dew point changes in the mixture of admixed gases and air under the conditions of using traditional heat recovery technologies and without them in different boiler modes and with different parts of recirculated gases were established. Problems of ensuring the operability and reliability of such boiler plants are highlighted. It is shown that these problems are related to condensate formation on the internal surfaces of air ducts and their freezing in some operating modes during in the cold period of the heating season. It is also shown that an effective solution to existing problems can be the use of air heaters in heat recovery systems to preheat the blown air before its mixing with recirculation gases. Originality. For the first time, the thermal and humidity operation modes of the air-supply ducts of heating boiler plants with increased environmental efficiency, which is ensured by boiler exhaust gases recirculation into the blown air, have been investigated. Practical value. The obtained research results will be used in the design of systems of recirculation and heat recovery of heat-generating devices’ exhaust gases to improve their environmental and thermal efficiency.

Experimental demonstration of the hybrid solar receiver combustor

<div class="section abstract"><div class="htmlview paragraph">Environmental policies and fuel costs have driven the development of new technologies for internal combustion engines. In this sense, the use of mixtures with small portions of fuel allows lower fuel consumption and pollutants emissions, emerging as a promising strategy. Despite the advantages, lean burn requires a larger energy source to provide satisfactory flame propagation speed and consequently a stable combustion. The use of pre-chamber ignition systems (PCIS) has been used in SI engines to assist the start of combustion of lean mixtures, in which a supplementary fuel system can stratify the amount of either liquid or gaseous fuels supplied to the pre-chamber. In this context, this paper aims to evaluate combustion characteristics of a commercial engine with the use of stratified PCIS operating with impoverished mixtures of ethanol-air in main-chamber and hydrogen assistance in pre-chamber. For this analysis bench dynamometer tests were performed evaluating cylinder pressure, exhaust gas temperature, fuel conversion efficiency, cycle thermal efficiency, coefficient of variation of the indicated mean effective pressure, apparent heat release rate, flame development angle and burn duration. As expected, the high amount of energy supplied by the PCIS favored combustion characteristics and exhaust gas temperatures that points to favorable conditions to reduce emissions and fuel consumption. Improvement on combustion stability can also enable the extension of lean limit, making the system even more attractive.</div></div>

Owing to the energy crisis and pollution problems of today investigations have concentrated on decreasing fuel consumption and on lowering the concentration of toxic components in combustion products by using exhaust gas after treatments methods like PM filters and EGR for NOx reduction. In this study, the combustion characteristics of diesel fuel were compared with that pr oduced from adding EGR at several percentages to air manifold. The tests were performed in a four-cylinder direct injection (DI) diesel engine at constant engine speed (1500 rpm) and variable loads (from no load to 86 kN/m2), the tests were repeated with constant load (77 kN/m2) and variable engine speeds (from 1250 to 3000 rpm).The experimental results showed that adding EGR to diesel engine provided significant reductions in brake power (bp), brake thermal efficiency and exhaust gas temperatures, while high increments in brake specific fuel consumption (bsfc). High EGR percentage (as 30% in this article) caused an 11.7% reduction in brake thermal efficiency, 26.38% reduction in exhaust gas temperatures and 12.28% in volumetric efficiency at full load conditions.

The Hydroxyl Tagging Velocimetry (HTV) technique has been applied to the measurement of engine exhaust velocities for an aviation gas turbine engine with augmentor capabilities. The J85-GE-5 engine exhaust was measured to be 110 m/s at idle and ramping up to 540 m/s at full throttle conditions. This information can be useful for the development of a noncontact thrust measurement system, which would rely on fluid flow measurements, rather than the use of load cells, to infer engine thrust. For the augmented (afterburner) mode of operation, the HTV tag lines were not present in the camera field of view; instead, there was significant fluorescence indicating turbulent mixing between fluorescing and nonfluorescing flow regions. The tag line absorption and concomitant exhaust gas fluorescence is probably a result of unreacted kerosene vapor exiting the afterburning gas turbine engine. Although this prevents the HTV technique from being applied to the afterburning engine, it can provide useful information about the instantaneous spatial distribution of fuel in the engine exhaust, and this information could be used to understand the processes occurring inside the engine in regards to its augmented operation.

<div class="htmlview paragraph">The performance characteristics of two-stroke engines are highly dependent upon the gas dynamic wave action in the exhaust system. In a tuned high performance exhaust system, negative suction pulses aid induction of charge into the cylinder, while positive waves aid its retention. The timing of these waves is closely related to the acoustic velocity, and is therefore dependent on the exhaust gas temperature (EGT).</div> <div class="htmlview paragraph">In advanced engine management systems, the control strategy may be tailored to influence the EGT, and to maximize the beneficial influence of the gas dynamics in the exhaust. Therefore, accurate measurement of EGT is required for development purposes, and real-time feedback could potentially be used as an input to the management system. However, accurate measurement of exhaust gas temperature is fraught with difficulties due to a number of sources of error. Steady state errors can arise due to conduction and radiation of heat from the thermocouple junction, while in transient operation, additional errors arise due to the slow responses of the robust thermocouples which are required to survive the harsh environment.</div> <div class="htmlview paragraph">In this study, the influence of the thermocouple geometry on the steady state errors has been estimated, and a technique has been developed to reconstruct mathematically the instantaneous temperature from the output of two dissimilar thermocouples. Results are presented to demonstrate that the reconstructed temperature correlates well with measurements from a fast-response thermocouple.</div>

<div class="section abstract"><div class="htmlview paragraph">To efficiently reduce the required experimental data and improve the prediction accuracy, a virtual engine model has been built by integrating an artificial neural network (ANN) system consisting of multiple subnets with the genetic algorithm (GA). The GA algorithm could reduce the risk of local minima and lead to a more efficient training process. The engine model has been adopted to predict the combustion phases (including CA10, CA50 and CA90), exhaust gas temperature, brake specific fuel consumption rate (b<sub>e</sub>) and engine emissions which are un-burnt hydrocarbon (UBHC), NOx and CO. The results are then compared with the experimental data from around 5000 operating points of a boosted DISI engine running at universal performance map and conditions with various valve timing configurations. The mean absolute errors of combustion phases are all below 1.0 crank angle degree. The averaged errors of the exhaust gas temperature and b<sub>e</sub> are 10.1 K and 1.1%, respectively. The averaged relative errors of UBHC, NOx and CO are close to 2.67%, 2.49% and 3.84%, respectively. Furthermore, the predicted results and experimental data show satisfying similar trends in terms of the CA 50 and combustion duration under different crank speed and brake specific fuel consumption rate under different VVT configurations. With a 2.2 GHz single-core processor, the turnover time for one single engine cycle calculation using the virtual engine model is less than one-tenth of the real wall time. This illustrates the potential of the proposed model for hardware in the loop (HiL) system and the virtual real drive emission (RDE) development.</div></div>

Late fuel post-injections are the most usual strategy to reach high exhaust temperature for the active regeneration of diesel particulate filters. However, it is important to optimise these strategies in order to mitigate their negative effect on the engine fuel consumption. This work aims at understanding the influence of the post-injection parameters, such as its start of injection and its fuel quantity, on the duration of the regeneration event and the fuel consumption along it. For this purpose, a set of computational models are employed to figure out in a holistic way the involved phenomena in the interaction between the engine and the exhaust gas aftertreatment system. Firstly, an engine model is implemented to evaluate the effect of the late fuel post-injection pattern on the gas properties at the exhaust aftertreatment system inlet in different steady-state operating conditions. These are selected to provide representative boundary conditions of the exhaust gas flow concerning dwell time, exhaust temperature and O 2 concentration. In this way, the results are later applied to the analysis of the diesel oxidation catalyst and wall-flow particulate filter responses. The dependence of the diesel particulate filter (DPF) inlet temperature is discussed based on the efficiency of each post-injection strategy to increase the exhaust gas temperature. Next, the influence on the dynamics of the regeneration of the post-injection parameters through the change in gas temperature and O 2 concentration is finally studied distinguishing the pre-heating, maximum reactivity and late soot oxidation stages as well as the required fuel consumption to complete the regeneration process.

Improvement of condition monitoring (CM) systems for wind turbines (WTs) and reduction of the cost of wind energy are possible if knowledge about the condition of different WT components is available. CM based on the WT drive train shaft torque signal can give a better understanding of the gearbox failure mechanisms as well as provide a method for detecting mass imbalance and aerodynamic asymmetry. The major obstacle preventing the industrial application of CM based on the shaft torque signal is the costly measurement equipment which is impractical for long‐term use on operating WTs. This paper suggests a novel approach for low‐cost, indirect monitoring of the shaft torque from standard WT measurements. The shaft torque is estimated recursively from measurements of generator torque, high speed shaft and low speed shaft angular speeds using the well‐known Kalman filter theory. The performance of the augmented Kalman filter with fading memory (AKFF) is compared with the augmented Kalman filter (AKF) using simulated data of the WT for different load conditions, measurement noise levels and WT fault scenarios. A multiple‐model algorithm, based on a set of different Kalman filters, is designed for practical implementation of the shaft torque estimator. Its performance is validated for a scenario where there are frequent changes of operating points. The proposed cost‐effective shaft torque estimator overcomes all major problems, which prevent the industrial application of CM systems based on shaft torque measurements. Future work will be focused on validating the method using experimental data and developing suitable signal processing algorithms for fault detection. Copyright © 2013 John Wiley & Sons, Ltd.