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Utilising pyrolysis as a waste tyre processing technology has various economic and social advantages, along with the fact that it is an effective conversion method. Despite extensive research and a notable likelihood of success, this technology has not yet seen implementation in industrial and commercial settings. In this review, over 100 recent publications are reviewed and summarised to give attention to the current state of global tyre waste management, pyrolysis technology, and plastic waste conversion into liquid fuel. The study also investigated the suitability of pyrolysis oil for use in diesel engines and provided the results on diesel engine performance and emission characteristics. Most studies show that discarded tyres can yield 40–60% liquid oil with a calorific value of more than 40 MJ/kg, indicating that they are appropriate for direct use as boiler and furnace fuel. It has a low cetane index, as well as high viscosity, density, and aromatic content. According to diesel engine performance and emission studies, the power output and combustion efficiency of tyre pyrolysis oil are equivalent to diesel fuel, but engine emissions (NOX, CO, CO, SOX, and HC) are significantly greater in most circumstances. These findings indicate that tyre pyrolysis oil is not suitable for direct use in commercial automobile engines, but it can be utilised as a fuel additive or combined with other fuels.

Since automobile engine fault is the main factor leading to a vehicle breaking down, engine fault diagnosis has captured a lot of attention. Fault diagnosis identifies fault types to facilitate maintenance. However, the method of the warning before the fault occurs is more attractive to users and is more challenging. Therefore, this study would like to explore the feasibility of implementing automobile engine fault early warning based on the fault diagnosis model. First, the theoretical method of a fault domain is established, and the state of the engine is regarded as a point in n-dimensional space. The normal or fault of the engine will correspond to different state domains in this space. Second, to diagnose multiple fault types at the same time, an ensemble model based on multiple machine learning methods is established. The probability outputs by the ensemble model measure the distance between the point and each fault domain in the space. Finally, considering the temporal factor, an early warning threshold is established based on the probability, and a fault warning model is established by using the dual probability structure. Comparative experiments show that the proposed method can greatly reduce the calculation time based on ensuring the accuracy of early warning and is suitable for real-time early warning of multiple faults.

PurposeThe purpose of this study is to present a system dynamic (SD)-based remanufacturing economic analysis model of used automobile engine under two recycling modes. The authors will compare the remanufacturing cost, sales profit and sales revenue from time and space dimensions incurred in different recycling modes in the long run.Design/methodology/approachThe remanufacturing economic analysis model is based on SD methodology. The authors can simulate the relations of impact factors on automobile engine recycling and remanufacturing and further analyze and compare the cost, sales profit and sales revenue incurred in different recycling modes in the long term.FindingsSinotruk Steyr engine remanufacturing in Shandong province is taken as the research case subject. The revenue, cost and profit under the two recycling modes from 2015 to 2035 are analyzed and compared. The results show that different recycling modes have significant varying influence on the economy of engine remanufacturing.Originality/valueThis economic analysis model can provide a method reference to decide the recycling mode for auto components and other product remanufacturing. Moreover, this model can guide and support the sustainable development of remanufacturing industry.

Computational Fluid Dynamics is used to assess the thermal (heat transfer) performances of an automobile engine considering different grille opening and closing degrees. For this purpose the entire vehicle is modelled and three fundamental aspects are examined, namely, the open area of the air intake grille, the position of the upper and lower grilles and their shape. The results show that the opening area and position of the grille have some influence also on the aerodynamic characteristics of the automobile. With an increase in the opening angle of the grille, the CD (Drag Coefficient) value of the whole vehicle becomes higher. When the air intake grille of the car is fully open or closed, the CD value is 0.35434 or 0.31777, respectively, that is, the flow resistance in the engine compartment accounts for 10.32% of the CD value for the whole automobile.

The technical performance of recent automobiles is highly progressed and standardized across different manufacturers. This study seeks to derive a semantic space of engine acceleration sound quality for end users and identify the relation with sound characteristics. For this study, two affective attributes: ‘refined’ and ‘powerful’, and eight acoustic parameters considering revolutions per minute were used to determine the correlation coefficient for those affective attributes. In the experiment, a total of 35 automobiles were selected. Each of the 3rd gear wide open throttle sounds was recorded and evaluated by 42 adult subjects with normal hearing ability and driving license. Their subjective evaluations were analyzed using factor analysis, independent t-test, correlation analysis, and regression analysis. The prediction models for the affective dimensions show distinct differences for the revolutions per minute. From the experiment, it was confirmed that the customers’ affective response can be predicted through the acoustic parameters. In addition, it was found that the initial revolutions per minute in the accelerated condition had the greatest influence on the affective response. This study can be a useful guideline to design engine acceleration sounds that satisfy customers’ affective experience.

The automobile engine pump is an important part of the automobile cooling system, and has a direct influence on the engine performance. Based on the SST k-ω turbulence model, unsteady numerical simulation for an automobile engine pump with different tip clearances was carried out by Fluent. To study the flow field characteristics and pressure fluctuation, the characteristics of secondary flow distribution in volute are also analyzed. The result shows that the pressure fluctuation characteristics of the flow field show obvious periodic variation at different levels of tip clearances. The peak value of pressure fluctuation at each monitoring point is dependent on the blade frequency. At the same time, with the increase of the tip clearance, the pressure fluctuation in the blade and volute is gradually increased, while the pressure fluctuation at the tip is reduced clearance. The pressure gradient in the pump also varies periodically with the rotation of the impeller. With the increase of the tip clearance, the pressure of the impeller, volute and tip clearance is gradually decreased. There are secondary flow vortexes inside the impeller, volute outlet and volute section. With the increase of tip clearance, the vortex intensity in the impeller channel is weakened, and the vortex strength at the volute outlet is intensified. On the cross section of the volute, the morphology of most vortexes has insignificant changes, but the vortex intensity decreased.

Hydrogen as carbon-free fuel is a very promising candidate for climate-neutral internal combustion engine operation. In comparison to other renewable fuels, hydrogen does obviously not produce CO2 emissions. In this work, two concepts of hydrogen internal combustion engines (H2-ICEs) are investigated experimentally. One approach is the modification of a state-of-the-art gasoline passenger car engine using hydrogen direct injection. It targets gasoline-like specific power output by mixture enrichment down to stoichiometric operation. Another approach is to use a heavy-duty diesel engine equipped with spark ignition and hydrogen port fuel injection. Here, a diesel-like indicated efficiency is targeted through constant lean-burn operation. The measurement results show that both approaches are applicable. For the gasoline engine-based concept, stoichiometric operation requires a three-way catalyst or a three-way NOX storage catalyst as the primary exhaust gas aftertreatment system. For the diesel engine-based concept, state-of-the-art selective catalytic reduction (SCR) catalysts can be used to reduce the NOx emissions, provided the engine calibration ensures sufficient exhaust gas temperature levels. In conclusion, while H2-ICEs present new challenges for the development of the exhaust gas aftertreatment systems, they are capable to realize zero-impact tailpipe emission operation.

With the advancements in player tracking technology, the topic of fatigue and pacing in team sport has become increasingly popular in recent years. Initially based upon a pre-conceived pacing schema, a central metabolic control system is proposed to guide the movement of players during team sport matches, which can be consciously modified based on afferent signals from the various physiological systems and in response to environmental cues. On the basis of this theory, coupled with the collective findings from motion-analysis research, we sought to define the different pacing strategies employed by team sport players. Whole-match players adopt a ‘slow-positive’ pacing profile (gradual decline in total running intensity), which appears to be global across the different team sports. High-intensity movement also declines in a ‘slow-positive’ manner across most team sport matches. The duration of the exercise bout appears to be important for the selected exercise intensity, with the first introduction to a match as a substitute or interchange player resulting in a ‘one bout, all out’ strategy. In a limited interchange environment, a second introduction to the match results in a ‘second-bout reserve’ strategy; otherwise, the ‘one bout, all out’ strategy is likely to be adopted. These pacing profiles are proposed to reflect the presence of a central regulator that controls the movement intensity of the player to optimize performance, as well as avoiding the harmful failure of any physiological system. The presence of ‘temporary fatigue’ reflects this process, whereby exercise intensity is consciously modulated from within the framework of a global pacing schema.

Diamond-like carbon (DLC) coatings have gained wide attraction, due to ultra-low coefficient of friction, high resistance to wear, excellent mechanical properties, and inert to chemical substance, especially in the automobile industry in the last decade. However, a lot of research is still carried out to improve the adhesion properties of DLC coatings to metallic substrate to prevent debonding caused mostly by high internal compressive stress and the difference in thermal expansivity between the metallic substrate and the DLC coatings. Consequently, to improve the adhesion of DLC coatings on metallic substrate, the use of interlayers (Si, SiH and Cr, CrN, Ti and TiN) and metallic (Mo, Ti, Cr, and W) and non-metallic (Si, N, and F) doping elements has been put to use. The interlayers form a transition layer between the metallic substrate and the DLC coating, thereby reducing the thermal expansivity between the metallic substrate and the DLC coatings. On the other hand, the metallic and non-metallic doping elements help in reducing the internal compressive stress in the DLC coatings. The present review article focuses mainly on the deposition techniques, characterisation techniques, and improvement of the adhesion properties of DLC coatings on metallic substrates. It showcases Cr-based interlayers and W/WC dopants as an efficient way to improve adhesion properties of DLC coatings for tribological and tribo-corrosion application in the automobile industry.

Owing to the significance of improving fuel economy, reducing emissions, and extending the durability of engine components, this study focused on the tribological performance of nano-additives. In this study, copper (Cu) and graphene (Gr) nanomaterials were dispersed in a fully formulated engine oil (5W-30) with different concentrations. The tribological trials were investigated under various speeds and loads, utilizing a reciprocating tribometer to mimic the ring/liner interfaces in the engine. The frictional surface morphologies were comprehensively analyzed using electron probe X-ray microanalysis (EPMA), field emission scanning electron microscopy (FESEM), energy dispersive spectrometer (EDS), and three dimensional (3D) surface profilometry to explore the mechanisms responsible for improving the tribological performance of the frictional sliding parts in the engine. The tribological test results illustrated that lubrication by nano-additives reduced the wear rate (WR) and friction coefficient (COF) by 25%–30% and 26.5%–32.6%, respectively, as compared with 5W-30. The results showed that this is a promising approach for increasing the durability and lifespan of frictional sliding components and fuel economy in automobile engines.