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The cylinder of marine diesel engine, as the power supply to the marine diesel engine, would lead dramatically damage to the engine once faults occurred. To avoid the situation, we develop a novel combinational approach using an improved genetic algorithm (GA) and multilayer perceptron (MLP). Firstly, chaos theory is carried out on the standard GA to prevent premature convergence. The improvements on the GA consist of population initialized by chaotic mapping, chaotic crossover, and chaotic mutation operator. Secondly, the Levenberg–Marquardt algorithm is used to train the MLP to accelerate the convergence speed of the MLP. Thirdly, the improved GA is used to optimize the initial weights and thresholds of MLP to further improve the performance of MLP. Finally, the proposed model is applied to the cylinder of a marine diesel engine for fault diagnosis. Compared with traditional approaches, the proposed method obtains more ideal solutions. Results demonstrate that the proposed method could effectively identify ten common faults of the marine diesel engine cylinder, and the average correct ratio of fault diagnosis can exceed 95%.

Renewable synthetic fuels offer the opportunity to significantly reduce carbon dioxide (CO2) emissions worldwide if burned in the internal combustion engines of existing and future passenger car fleets. To evaluate this potential, two renewable synthetic gasoline fuels and alcohol blends that can be produced via the methanol-to-gasoline (MtG) synthesis process are evaluated in this study. The first synthetic gasoline, hereafter referred to as MtG, was developed by Chemieanlagenbau Chemnitz GmbH and Technische Universität Bergakademie Freiberg, produced within the closed carbon cycle mobility (C³-Mobility) project, and was blended with 10%(V/V) ethanol (MtG-E10), 20%(V/V) ethanol (MtG-E20), 15%(V/V) methanol (MtG-M15), and 15%(V/V) 2-butanol (MtG-2Bu15). The second synthetic fuel, named POSYN (POrsche SYNthetic fuel), was developed by Porsche. The suitability of the synthetic fuels was experimentally investigated in a spark-ignition (SI) single-cylinder research engine with a compression ratio (CR) of 10.8 and compared with conventional gasoline fuel with Research Octane Number 95 and 10%(V/V) ethanol (RON95 E10) gasoline fuel. Load variations at a constant engine speed of 2500 rpm showed no significant differences between Methanol-to-Gasoline with 10%(V/V) ethanol (MtG-E10) and RON95 E10 in terms of both combustion performance and emissions. Additionally, a load variation with MtG-E10 and RON95 E10 at an engine speed of 3000 rpm was performed on a commercially available BMW multi-cylinder engine (MCE), which confirmed that both these fuels show an almost identical combustion and emission behavior. However, the knock resistance improved with higher alcohol fractions. Because of the favorable anti-knock properties of methanol, Methanol-to-Gasoline with 15%(V/V) methanol (MtG-M15) showed the highest maximum net indicated efficiency of 39.33%. This is 2% more than with Methanol-to-Gasoline with 20%(V/V) ethanol (MtG-E20), despite the lower alcohol volume fraction. In contrast, Methanol-to-Gasoline with 15%(V/V) 2-butanol (MtG-2Bu15) showed no improvement. POSYN enabled a significant efficiency advantage over RON95 E10 because of its high knock resistance, however, achieved the same maximum engine load because of the reduced octane sensitivity. The variation of the relative air/fuel ratio at an engine speed of 2500 rpm and an engine load of 16 bar net indicated mean effective pressure confirmed these findings. The highest net indicated efficiency of 42.4% was achieved with POSYN at a relative air/fuel ratio of 1.6. The lean limit could not be increased with the synthetic fuels and alcohol blends albeit with an improved combustion stability.

Internal combustion (IC) engines are used widely as the primary power source for automobiles of all types, cars, motorcycles, and trucks. Because of the high combustion temperatures involved in the operation, the excess heat is removed by means of extended fins that increase the surface area for adequate cooling. Significant improvement in the heat dissipation characteristics of the engine cylinder can be achieved by optimizing the design of these fins. The aim of this study is to evaluate the thermal performance of engine cylinder fins using an analytical system of finite element analysis (ANSYS FEA) software, using a direct optimization (DO) approach to identify optimal fin design. Analysis shows that fin length and width play critical roles in improving cooling efficiency, lowering the maximum temperature within the cylinder to 549.46 K and enhancing total heat flux to 7225.31 W/m2, which is a 25.87% increase from the generic design, capable of heating removal of 5740.22 W/m2. The current fin design is effective but could be improved in heat dissipation, mainly at fin tips. To optimize thermal performance while minimizing material costs, a balanced fin dimension is recommended. Alternative materials, transient heating analysis, and experimental verification may be examined in the future to achieve a total understanding of fin geometry and behavior under real operating conditions. These insights lay a foundation to accelerate cooling systems development in the automotive, aerospace, and heavy equipment industries, where efficient heat transfer is key for performance and long-term durability.

This article presents a misfire detection index for motorcycles with a single-cylinder engine. Compared with automobiles with multicylinder engines, attempts to diagnose single-cylinder motorcycle engine misfires have been rare. Therefore, a new index, detrended engine rpm amplitude (DERA), is proposed to detect misfires using tooth time measured by the crankshaft position sensor; thus, there is no additional cost for the DERA index. This index is defined as the difference between the squares of the maximum and minimum values of engine speed (rpm) detrended by the engine speed trend line, instead of the linear regression method. Thus calculating the DERA index becomes simple and fast, and it is advantageous to reduce the computation time. Here the engine speed trend line is a line connecting the engine speeds at the first teeth of the current and subsequent cycles. The analysis of the optimal threshold for detecting misfires reveals that DERA yields a good misfire detection rate of more than 98% for an engine speed range of 3,000-8,000 rpm in load conditions of over 50%. If the lower boundary limit for the load over which misfires can be accurately detected is clearly defined, a good detection rate can be achieved even under load conditions below 50%. If only two teeth among the entire teeth can be specified optimally that best demonstrate the changes of the detrended engine speed (DRPM) due to misfire, the DERA index could be used to diagnose misfires even for motorcycles with a small number of teeth on the target wheel.

The object of this study is the power system of internal combustion engines in wheeled vehicles operating under conditions of partial cylinder deactivation. The study addresses the problem of decreased wheel power due to mechanical (pumping) losses in non-firing cylinders, which limits the efficiency of cylinder deactivation strategies aimed at improving fuel economy. A new method has been developed to determine the work and power output of the engine during acceleration with one or more cylinders deactivated. This method enables direct and accurate assessment of vehicle performance under real-world operating conditions. Experimental tests were conducted on two vehicle types: a Daewoo Lanos 1.5i passenger car and a KrAZ-255B heavy-duty truck. In both cases, cylinder deactivation was implemented by cutting off fuel supply, and on the KrAZ-255B, additional drainage of residual fuel from high-pressure lines was used to eliminate injector resistance. The results revealed a notable reduction in wheel power when cylinders were disabled; however, eliminating mechanical losses in the deactivated cylinders significantly reduced this power drop. In the Daewoo Lanos 1.5i, the power loss decreased by factors of 1.44 and 2.98 when one or two cylinders were deactivated. For the KrAZ-255B, reductions of 1.1 and 3.09 were recorded. These results are explained by the mechanical drag caused by the pumping action of non-firing cylinders. When this resistance is removed, power transmission becomes more efficient. The distinctive feature of this study is the quantification of mechanical losses and their effect on vehicle performance under real conditions. The method can be practically applied to optimize powertrain efficiency, especially in heavy vehicles and systems operating under varying load conditions.

This study delves into the impact of electric turbochargers on fuel efficiency and emissions in ethanol-gasoline blends. Informed by relevant literature, the research zeroes in on the positive influence of electric turbochargers, emphasizing their role in reducing fuel consumption and emissions while also addressing the trade-off between flame characteristics and NOx emissions. The experimental focus is on the injection modification of a single cylinder, with samples including engines equipped with and without an electric turbocharger. Statistical analysis utilizing percentage-based methods reveals that this technology leads to a substantial 94% reduction in CO emissions at idle speed, a 49% decrease in HC emissions at idle speed, and a 10% increase in CO2 at idle speed. Additionally, it also results in a notable 16.04% reduction in fuel consumption at 40 km/h. These outcomes underscore the potential of electric turbochargers to enhance automotive efficiency and sustainability while acknowledging the trade-off that necessitates further exploration for optimal emission control. The research provides concrete insights for refining electric turbocharger technology and optimizing its practical application.

Two new misfire detection indexes for single-cylinder motorcycle engines—dubbed gap distance (GD) and gap slope (GS)—are proposed in this study. GD and GS quantify the change in engine angular acceleration using the tooth time measured by the crankshaft position sensor (CKPS). GD is defined as the product of the spacing distance I (the distance from the top dead center at the explosion stroke [TDC2] to the engine speed trend line parallel to the engine speed axis) and spacing distance II (the distance from the bottom dead center at the expansion stroke [BDC2] to the engine speed trend line parallel to the engine speed axis). GS is defined as the difference between the two slopes between the engine speed inclination line and the engine speed trend line. Here the engine speed trend line connects two engine speeds at the top dead center at the intake stroke (TDC1) of the current and subsequent cycles. The GD and GS indexes can detect misfires using the engine speeds at only four teeth. The location of these four teeth could be changed to best simulate the change in engine angular acceleration for engines. The threshold range for GD and GS lies between the point where the misfire detection rate reaches 100% and the point where both the ratio of misfire detection to misfire signal (Mdtn/Msig) and the ratio of misfire signal to misfire detection (Msig/Mdtn) begin to deviate from 100%. Both GD and GS show a good misfire detection rate of approximately 99% and a perfect detection fault rate of 0% for an engine speed range of 3,000-8,000 under load conditions of over 50%. If the lower boundary limit for the load over which misfires can be accurately detected is clearly defined, a good detection rate can be achieved even under load conditions below 50%.

Design of engine cylinder is always a great concern to deal with temperature variations owing to overheating. Improving heat transfer rate of cylinder using fins are common. Present work deals with increase in heat through put by utilizing air as operational fluid. The objectives of present study are to examine the effect of extended surface geometry on heat through put of engine cylinder and establish an optimum geometry under the ambient conditions using transient thermal analysis. The results were validated with available literature. For having higher thermal conductivity, Al 6061 Alloy (180 W/mK) is taken as the preferred choice for fabricating the extended cooling surface of engine cylinder.

Pilot-diesel-ignition ammonia combustion engines have attracted widespread attentions from the maritime sector, but there are still bottleneck problems such as high unburned NH 3 and N 2 O emissions as well as low thermal efficiency that need to be solved before further applications. In this study, a concept termed as in-cylinder reforming gas recirculation is initiated to simultaneously improve the thermal efficiency and reduce the unburned NH 3 , NO x , N 2 O and greenhouse gas emissions of pilot-diesel-ignition ammonia combustion engine. For this concept, one cylinder of the multi-cylinder engine operates rich of stoichiometric and the excess ammonia in the cylinder is partially decomposed into hydrogen, then the exhaust of this dedicated reforming cylinder is recirculated into the other cylinders and therefore the advantages of hydrogen-enriched combustion and exhaust gas recirculation can be combined. The results show that at 3% diesel energetic ratio and 1000 rpm, the engine can increase the indicated thermal efficiency by 15.8% and reduce the unburned NH 3 by 89.3%, N 2 O by 91.2% compared to the base/traditional ammonia engine without the proposed method. At the same time, it is able to reduce carbon footprint by 97.0% and greenhouse gases by 94.0% compared to the traditional pure diesel mode. Pilot-diesel-ignition ammonia combustion engines effective adoption is still limited by high unburned emissions and low thermal efficiency. Here, authors propose an in-cylinder reforming gas recirculation concept to improve engine thermal efficiency while reducing unburned NH3, NOx, N2O and GHG emissions.

Balance shafts are often used to improve the engine vibration characteristics of three-cylinder engines. The balance damping gear with a damping ring is an important part connecting the crankshaft and the balance shaft transmission. The stiffness characteristics of the damping ring and the unbalance of the gear have an important influence on its vibration suppression performance, but the coupled influence of the stiffness characteristics of the damping ring and the unbalanced characteristics of the vibration damping gear is unknown. In this paper, a multi-body dynamic bending–torsional coupling model of the transmission system of a three-cylinder engine with a balance damping gear is constructed considering the equivalent stiffness of the balance shaft support. Based on the fourth-order Runge–Kutta method, the influence laws of different rotational speeds, load torques, gear unbalance, radial stiffness and torsional stiffness of the damping ring on the vibration characteristics of the transmission system are obtained. The results show that the vibration amplitude increases linearly with the increase in the rotational speed and the amount of unbalance. As the load torque increases, the noise radiation of the system increases. The change in the equivalent torsional stiffness of the damping ring has little effect on the radial vibration suppression effect of the gear. As the equivalent radial stiffness of the damping ring increases, the vibration suppression rate decreases linearly. Combined with the calculation formula of damping ring stiffness, when the inner and outer diameters of the damping ring are relatively large, the vibration suppression performance decreases sharply with the increase in the thickness of the damping ring. Therefore, in order to achieve a better vibration attenuation effect, the inner to outer diameter ratio of the damping ring should be given priority in the design of the damping gear. Thus, the thickness of the design can meet the requirements of the vibration attenuation performance and a vibration attenuation of more than 90% of the radial vibration can be achieved. The model of the damping ring size and the vibration suppression effect established based on the method presented in this paper can be used to guide the design of balance damping gears.