Engine Layout Research Articles

Morphological Characteristics of Constrained Meandering Rivers in the Loess Plateau

In the Loess Plateau of China, loess is widely distributed and forms a unique geomorphic feature of the world. Meanwhile, the Yellow River water and sediment regulation system is under construction. Nonetheless, the morphological characteristics of constrained meandering rivers in the Loess Plateau are still unknown due to the difficulty of extracting the sediment-laden water body. An improved method is proposed based on Landsat 8 imagery, which automatically extracts the multi-band spectral relationship of high-sediment-concentration rivers in valleys. This study analyzes the morphological characteristics of constrained meandering rivers in the middle reaches of the Yellow River Basin, including their sinuosity, periodicity, curvature, and skewness based on the deflection points bend segmentation and continuous wavelet transform methods. These characteristics are then compared with those of other constrained meandering rivers and alluvial meandering rivers. The results show that the sinuosity of the constrained river bends is generally low (with an average of 1.55) due to limitations imposed by the riverbanks, which prevent full development. The average dimensionless curvature radius of the constrained rivers is 18.72, lower than that of alluvial rivers. The skewing angle of the constrained river bends typically inclines upstream, with a proportion reaching 59.44%. In constrained river bends, as the sinuosity increases, the proportion of bends skewing upstream initially increases and then gradually decreases. This indicates that constrained river bends can develop similarly to alluvial bends at lower sinuosity but are limited by the mountains on both sides at medium sinuosity. The analysis of river characteristics in regions with different geological structures reveals the effect of geological structures on the formation of constrained rivers in the Loess Plateau. These findings can provide a reference for selecting reservoir dam sites and are important for the dredging engineering layout in the middle reaches of the Loess Plateau. They also offer quantitative explanations for the meandering characteristics of these rivers.

Design of a novel impulse turbine for exhaust energy recovery in a commercial load carrier single cylinder diesel engine

A significant fraction of the fuel energy supplied in a diesel engine is wasted into the atmosphere through the exhaust gases. Although most modern-day diesel engines are turbocharged, a few remain naturally aspirated. Due to technical challenges, single-cylinder engines are not turbocharged and remain naturally aspirated (NA). The intermittent and pulsated exhaust gas flow tends to choke the turbine and increase the back pressure. On the other hand, supercharging a single-cylinder engine leads to superior performance at the expense of fuel efficiency, as a significant fraction of the energy is wasted in the exhaust. The current study employs a novel crank shaft coupled impulse turbine for effective exhaust energy recovery in a supercharged, high-speed, commercial single-cylinder diesel engine. This novel impulse turbo-compounded and supercharged engine layout was simulated using a 1D model developed using AVL BOOST software. Based on the results of the 1D model, the impulse turbine design was carried out. A CFD simulation of the impulse turbine was carried out using commercially available CONVERGE. The major design parameters, including blade profile, blade width, nozzle shape, size and angle, blade angles, blade speed, number of blades, and turbine outlet port opening, were optimized using the CFD software. The simulated results showed that the designed impulse turbine generated 2.67 kW of power, enhancing the power output of the supercharged engine by 21% at the rated operating condition. The turbine efficiency was 68%, considering the available kinetic energy at the exhaust. Simulation results indicate that the impulse turbine compounded supercharged engine could generate 15.4 kW of power, 45% higher than the base NA engine brake power output.

Analysis of Cylinder Comp Product Quality Control with Proposed Improvements at PT. Jakarta Automotive

In the era of globalization, the manufacturing industry faces its biggest challenge, namely the demands of consumer needs with high quality standards. Various kinds of waste often occur in the production process, one of which is caused by a poor layout of facilities, for example the arrangement of machines on the production line that is not suitable. This is a problem in the production process of machining cylinder comp at PT. Jakarta Automotive. With the aim of finding out the factors that cause product defects in machining cylinder comp and finding design of improvement proposals to reduce the defects that occur, this study uses a quantitative method to find DPMO and sigma values as an analysis of the cause of the problem. The result of this study was the discovery of less than optimal engine layout settings that caused TAP NG defects in the product. So that a design of a proposed improvement was made in the form of a change in the engine layout. In conclusion, in this study, it was identified that the non-optimal engine layout was the cause of the high defects. Therefore, improvements are proposed in the form of changing the engine layout on the production line with the aim of reducing the level of defects caused by a less than optimal layout.

Evaluation of highway debris flow hazard based on geomorphic evolution theory coupled with material response rate

Assessments of highway feasibility frequently lack the detailed data and geological information necessary to conduct hazard evaluations of debris flows. This study discusses the processes of debris flow development when regional rainfall meets the critical level required for debris flow initiation. It utilizes geomorphic evolution theory and establishes a regional risk assessment matrix for debris flow by combining information about gullies and source sensitivity. Considering the location relationship between the highway and debris flow gullies, a rapid evaluation method for debris flow risk assessment along the G318 highway in Sichuan Province is proposed by modifying the judgment matrix. The four debris flow gullies constructed during the upgrading project in Yajiang County, stretching from the west of the city to the Shearer Bay section, were analyzed via examples. The results show that, among the four selected debris flow gullies, two had medium hazard levels, and two had high hazard levels. The validation results are consistent with the actual results, implying that the evaluation method used in this study is accurate and feasible. This method is suitable for the rapid evaluation of debris flow disaster hazards in the feasibility assessment stage of a highway because it relies on readily available data sources, and the evaluation results are fast and convenient. The highway passes through four debris flow gullies, which directly impact the alignment of this particular section of the geological route and the engineering layout. Based on current specifications, the maximum impact range of a one-time debris flow under the given frequency conditions was calculated using the "rainfall method." The results showed that the maximum impact ranges of a debris flow, occurring once in 100 years, for four gullies would be 9.08 m, 9.09 m, 10.86 m, and 10.08 m. The safe clearance heights of bridges over the four gullies should be 14.58 m, 14.59 m, 16.36 m, and 16.3 m. Additionally, the safety clearance width for all gullies should be 5.0 m.

Accurate Delimitation of Mine Goaves Using Multi-Attribute Comprehensive Identification and Data Fusion Technologies in 3D Seismic Exploration

Existing goaves (e.g., shafts and roadways) in mines represent important hidden dangers during the production of underlying coal seams. In this view, the accurate identification, analysis, and delimitation of the scope of goaves have become important in the 3D seismic exploration of mines. In particular, an accurate identification of the boundary swing position of goaves for 3D seismic data volumes within a certain depth interval is key and difficult at the same time. Here, a wide-band and wide-azimuth observation system was used to obtain high-resolution 3D seismic data. The complex structure of a mine was analyzed, and a seismic double processing system was applied to verify the fine processing effect of a goaf and improve the resolution of the 3D seismic data. Based on the seismic attribute identification characteristics of the goaf structure, we decided to adopt multi-attribute comprehensive identification and data fusion technologies to accurately determine the position of the goaf and of its boundary. Combining this information with the mine roadway engineering layout, we verified the accurateness and correctness of the goaf boundary location. Our study provides a good example of the accurate identification of the 3D seismic data of a roadway goaf.

Identification of Key Areas for Ecological Conservation and Restoration based on Multi-source Data and Remote Sensing Time Series Analysis

Abstract. Ecological conservation and restoration of national land space is an important aspect for implementing the national ecological civilization strategy, and an important measure for establishing the national ecological security pattern and coordinating the systematic management of mountains, water, forests, fields, lakes, grass and sand. The identification of key areas for ecological conservation and restoration is a precondition to spatially and temporally laying out ecological conservation and restoration planning, which is crucial for the ecological conservation and restoration of national land space. Therefore, this paper considers Henan Province as the study area and carries the research and practice of identifying key areas for ecological conservation and restoration by integrating multi-source data and remote sensing time series analysis. Firstly, based on the Google Earth Engine (GEE) cloud platform and MOD13A1 data, the Mann-Kendall method is used to analyze the trend of time series NDVI in the study area from 2011 to 2020. Secondly, based on multi-source data such as meteorological, soil, topographic, net primary production (NPP), etc., an ecosystem health analysis and assessment based on ecosystem service trade-off and synergy is used to select ecological source. Finally, based on the results of time series NDVI analysis and ecological source selection, fusion analysis is used to identify key areas for ecological conservation and restoration. The results show that this proposed research framework not only considers the “static” ecosystem services and ecosystem health attributes, but also measures the “dynamic” ecosystem change trends. It can effectively identify key areas for ecological conservation and restoration in national space. The results of the study can provide technical support for the background survey, problem identification, planning and engineering layout of ecological conservation and restoration in the national land space.

Multidisciplinary Design Methodology for Micro-Gas-Turbines—Part I: Reduced Order Component Design and Modeling

Abstract Ultramicrogas turbines (UMGTs) for electric power generation up to 1 kW are a viable replacement technology for lithium batteries in drones due to their high energy density. Previous research has shown that small-scale effects disqualify conceptual design practices applied to larger gas turbines owing to highly coupled, nonlinear component interactions. To fill this gap, we propose an interdisciplinary conceptual design and analysis framework based on reduced order models. To this end, the current work is divided into two parts covering component design and system integration, analysis, and optimization. In Part I, automated conceptual design of all engine subcomponents is elaborated facilitating interdependent reduced order models for compressor, turbine, combustor and high-speed generator while also considering additive manufacturing constraints. In a second step, the reduced order performance models are compared to computational fluid dynamics (CFD) Reynolds-averaged-Navier–Stokes (RANS) simulations of various turbomachinery geometries as well as experimental data of combustor and high-speed generator prototypes, showing good agreement and thus validating the component modules. In conclusion, the first part of this work elaborates an automated and efficient method to conceptual design of all components required for a functional UMGT. Since the strategy is applicable independent of component arrangement and engine layout, the proposed methods offer a universal framework for small gas turbine generators.

Wind tunnel investigation of different engine layouts of a blended-wing-body transport

A 2% scale, cruising version of a 450-seat class Blended-Wing-Body (BWB) transport was tested in the China Aerodynamic Research and Development Center’s FL-26 2.4-by-2.4-meter subsonic wind tunnel. The focus of the wind tunnel test was to investigate the aerodynamic performance of the latest BWB transport design, which would also aid in choosing a final engine arrangement in the three most potential engine integration layouts. The wind tunnel model can be tested with and without the nacelle and has three sets of different nacelle/tail integration positions. Computational Fluid Dynamics (CFD) simulations were performed in engine-aircraft integration design to find appropriate nacelle installing parameters of each layout. The comparison of CFD with experimental results shows good agreement. Wind tunnel measurements indicate that the tail-mounted engine layout produces the minimum drag penalty, while the fuselage-mounted engine layout increases drag the most. Experimental pressure measurement illustrates the effect of nacelle integration on the wing-body surface pressure distribution. This experimental and numerical research provides a reference for future BWB Propulsion-Airframe Integration (PAI) design.

Waste Energy Recovery and Valorization in Internal Combustion Engines for Transportation

Internal Combustion Engines (ICE) are experiencing a transition era in which research and innovation are mainly pushed by environmental issues: emission reduction and fuel saving are indispensable requirements of the new technologies, otherwise the end of ICE is proposed in Europe. Modifications, in reality, are under discussion by 2026 but the environmental issues are anyway welcomed. In the transportation sector, today dominated by ICEs, it appears that the reduction in the propulsion power, hybridization at various degrees, and exhaust post-treatment improvements will guarantee technological solutions able to support the transition in the next couple of decades toward full electric propulsion. Waste Heat Recovery (WHR) is a very interesting opportunity since almost two-thirds of fuel energy is not converted into mechanically useful energy. Moreover, the integration with other thermal streams on board (cooling and lubricating mediums, EGR cooling) can add further value to the recovery opportunity as well as the concept of managing the engine thermal management which can produce a sensible contribution that is appreciated mainly during urban driving. A huge scientific effort is underway, and a great expectation is perceptible. More generally, the technological options that can achieve a reduction in overall fuel consumption and, thus, the improvement of global engine efficiency, are the most valuable when they can be introduced without massive changes to the engine layout. This happens in all the energy applications in which ICEs are involved since the recovery unit can be introduced in the exhaust line. The mechanical energy recovered can be easily transformed into electrical energy, so represents an interesting integration with the hybrid propulsion powertrains. In this paper, a review of the most important technologies referred to the WHR is presented, outlining advantages and drawbacks, and setting up the presently available technologies referred to the transportation sector.

Thermal comfort formation of the bus interior depending on the power unit layout

Energy consumption and thermal comfort are among the issues that research engineers of heating, ventilation and air conditioning systems deal with when investigating the most feasible solutions for their implementation. Existing methods of thermal comfort assessment are not optimized in two important and interrelated aspects: achieving thermal comfort (a) at the lowest possible energy consumption (b). Thermal comfort is situationally achieved when occupants perceive the ambient temperature, humidity, air movement and thermal radiation as ideal and do not prefer warmer or colder air or a different humidity level. Thermal comfort is defined by ASHRAE Standard 55 as a subjective concept characterized by the sum of sensations that create physical and mental well-being in a person. That is, he/she is in a state in which he/she feels comfortable and does not need to change one or more environmental parameters. Many studies have been conducted according to the international standards for thermal comfort in vehicles. The presence of a large number of people in the bus leads to a deterioration of the air quality in its interior. The loss of quality is mainly caused by gases resulting from breathing and other organic particles. The presence of moisture, combustion products, particles can also reduce the air quality in the interior. Air quality is affected by the design features of heating, ventilation and air conditioning systems, which largely depend on the location of the power unit, which is the subject of the research. The influence of the bus engine layout is analysed in the presented work: for the rear-engine layout, the location of the engine vertically in the interior and other cases are also considered. Special fans are installed in the engine compartment to remove heat emitted by the engine.

Comparison on the energy absorbed of volumetric and centrifugal pumps for automotive engine cooling

Engine thermal management can reduce significantly CO2 emissions in road vehicles without altering sensibly the engine layout. However, more efficient auxiliaries also participate to fuel consumption saving and, therefore, to CO2 emissions reduction. Typically, centrifugal cooling pumps are adopted as circulating devices, but their efficiency varies highly with rotational speed, wasting energy during real operation despite being optimized at the design point. Instead, volumetric pumps keep a high efficiency also far from it, enhancing the overall engine efficiency. In this paper, the performances of a screw-type volumetric pump have been compared with those of a centrifugal pump considering the same cooling circuit of a mid-size engine for passenger vehicles. Both pumps have been designed to satisfy the cooling flow rate required by the engine during a homologation cycle, while verifying their capability to cool the engine operating at maximum power. Once prototyped, the pumps performance maps have been measured, showing a high Best Efficiency Point for both cases. However, the screw pump has better performance in off-design conditions, being the centrifugal pump efficiency strictly dependent on its rotational speed which significantly changes during a real driving. The comparison of the two pumps has been done by reproducing the WLTC on a dynamic test bench. The rotational speed of the volumetric pump has been adjusted to deliver the same flow rate produced by the centrifugal pump as requested by the engine. Results show that the prototyped screw-type volumetric pump absorbs 21% less energy than the prototyped centrifugal pump, reducing CO2 emissions by 0.28 g/km.

Historical development of the coaxial contra-rotating propeller

AbstractWe review the development of the contra-rotating propellers from the origins to the present. Initially, these systems were proposed to increase speed, then to increase propulsive efficiency, and thus reduce fuel burn. Ultimately, they hit another environmental limit: too much noise. Acoustics has been in fact the main focus of the development in the past 30 years. Pioneering work done across countries demonstrated several unique features of this propulsor. Various embodiments are available, namely contra-rotating, counter-rotating, co-axial, tandem, open rotor and prop-fans, collectively named contra-rotating propellers. This review only considers concepts that have been applied to real aircraft, prototypes that are known to have been flight tested (about 70 vehicles), or representative laboratory models. Five classifications are proposed: pioneers (before 1940), golden years (1940–1950), Western airplanes (1950s onwards), Soviet-Russian airplanes (1950s onwards) and modern developments (1980s onwards). Selected experimental aircraft and laboratory concepts are mentioned, where these appear to advance the state-of-the-art. Power plants evolved from internal combustion engines to the modern gas turbine engines requiring new solutions. Engine layouts and propulsion configurations are analysed where appropriate. It is concluded that propulsive efficiency can only be achieved at a cost of multiple engineering problems, some of which remain unsolved.

Determination of the optimal parameters and engine layout for a strike unmanned aerial vehicle

The article describes the solution of a complex problem to determine the optimal parameters and engine layout for the power plant of an advanced unmanned aerial vehicle according to the methodology developed by the authors using the authors complex mathematical model and the well-known method of indirect statistical optimization based on self-organization. At the same time, the main aerodynamic and flight performance characteristics of the unmanned aerial vehicle under study, calculated according to engineering methods, are shown, as well as the parameters and characteristics of its power plant, calculated using the authors algorithm implemented in a complex mathematical model. The results of parametric studies are also presented using the example of assessing the influence of the bypass ratio on the characteristics of a power plant and the parameters of the unmanned aerial vehicle under study. The process of conducting optimization studies of the Unmanned aerial vehicle power plant system with a bypass turbojet engine with mixing of the circuit flows behind the turbine is described. At the same time, special attention is paid to the formulation of the optimization problem, the choice of criteria and changeable variables, as well as the analysis of the results obtained by comparing the efficiency of the system under study with different engine configurations according to the criteria of the aircraft level: maximum range according to two formed flight programs.

Re-Layout Tata Letak Bagian Percetakan Menggunakan Calullar Manufacturing System

Material handling in the production division of publisher X encountered several obstacles, including the transfer of material between production processes having cross-movement flows. This condition occurs as a result of an irregular engine layout. The impact of the conditions in the transfer of material in the production process is the distance of the transfer to be 968.6 m/day. This condition causes some machines to be repositioned, so that material transfer can run faster and more efficiently. One of the efforts to reduce material transfer is to re-plan the placement of production facilities by adopting the concept of a cellular manufacturing system or cellular manufacturing system that is feasible to be applied to the production process of publisher X. The cellular manufacturing system was chosen because it is in accordance with the number of characteristics of the publishing industry that requires the ability to anticipate changes. This rapid demand suits a particular market. This article describes how the results of rearranging and minimizing the distance of moving raw materials in the production section of publisher X by adopting the concept of a cellular manufacturing system and rearranging the layout of production facilities by using sorting using Sorting Algorithms. The selection of the Sorting Algorithms is based on consideration of the order of the output which is not coherent, so it needs to be sorted. Efficient sorting is needed to determine the part-machine incidence matrix which is then used in the development of cellular manufacturing systems. Program development on Visual Studio 2012 software shows the results of facility layout planning by grouping 20 machines and 11 products with this layout change, the total material handling distance is reduced by 371.8 m or by 61.61%

Numerical Evaluation on Large Ground-Effect Seaplane at Takeoff with Power Augmented Ram

Power-augmented ram has been considered as a promising solution for increasing lift coefficients for large ground-effect seaplanes that typically are required to take off at sea. To date, however, a quantitative evaluation of the power-augmented ram (PAR) technique is still lacking, except for a few conceptual analyses; and its possible technical barriers are unclear. In this study, a typical large-scale ground-effect vehicle is employed to assess the effect of the PAR on lift enhancement at takeoff using numerical simulation. The results show that high-lift enhancement can be obtained as front-installed engine jets ram into the open cavity between a wing and the ground. The jet flow produces high pressure on the lower surface of the wing, significantly increasing the lift. However, the high pressure is primarily imposed on the trailing-edge flap that is deflected down at takeoff, thus yielding a large nosedown pitching moment that is basically proportional to the lift increment. The extra pitching moment will pose a challenge to trimming the seaplane with conventional elevators. Reasonable designs (including multiple engine layouts, increasing nozzle area, and decreasing nozzle velocity) can improve the undesired pitching moment, thus achieving better aerodynamic performances.

Analysis of Multifactor Influence Model on Energy Dissipation Rate of Rough-Strips Energy Dissipator in the Spillway Bend

The rough-strips energy dissipator (R-SED) is applied to the bottom of the spillway bend and can play the role of energy dissipation and flow stabilization. In this study, based on 18 sets of orthogonal tests and the principle of dimensional analysis, a multifactor influence model of R-SED’s energy dissipation rate was proposed. A dimensionless factor k was introduced, which can reflect the comprehensive characteristics of the geometric dimensions of R-SEDs. The multifactor influence model of the energy dissipation rate considered nine factors, including bend radius of curvature Rc, bend width B, flow velocity of the bend inlet v , R-SED’s average height hL, R-SED’s arrangement angle θ, R-SED’s arrangement spacing ∆L, fluid density ρ, dynamic viscosity coefficient μ, and gravitational acceleration g . The residual sum of squares of the model (RSS) was 6.6% and the correlation coefficient R was 83.2% (>80%), indicating the universality and feasibility of the model. The independent variables of the multifactor model of the energy dissipation rate were ranked according to the Pearson value in descending order: (ΔL/Rc) > (θ) > (B/Rc) > (hL/Rc) > (1/Fr2). This indicates that R-SEDs’ layout parameters showed larger effects on the multifactor model of the energy dissipation rate, compared with the engineering layout parameters of the spillway. The maximum relative error between the predicted value of the multifactor model and the measured value of the validation group was 6.28%, indicating good agreement. In the orthogonal tests, scenario 5 had the highest energy dissipation rate (44.83%) with k = 0.023; scenario 16 had the largest k value (0.043), with an energy dissipation rate of 40.78%. The multifactor influence model of R-SEDs’ energy dissipation rate proposed in this paper was a semi-theoretical and semi-empirical calculation formula, which can provide reference and support for similar practical engineering designs.

Ecological risk changes and their relationship with exposed surface fraction in the karst region of southern China from 1990 to 2020

Due to anthropogenic disturbances, the karst region in southern China is vulnerable to ecological problems such as soil erosion and surface exposure. However, limited studies on variations in large-scale ecological risk (ER) and their influencing factors, particularly the coupling/decoupling relationship with an exposed surface fraction (ESF), make ER regulations and ecological restoration challenging. The present study evaluates the ER of eight typical karst provinces in Southern China from 1990 to 2020 using the technique for order preference by similarity to an ideal solution (TOPSIS) model and ecosystem services (habitat quality, water yield, carbon storage, soil conservation, and food production), and extracts the contemporaneous ESF using Landsat satellite data in Google Earth Engine (GEE). The spatiotemporal change of ER and ESF are analyzed, and their coupling/decoupling relationship and driving mechanism are explored using coupling coordination degree (CCD) and multi-scale geographically weighted regression (MGWR) models. The results show that: (1) Over the past 30 years, the ER has increased until 2010 and subsequently declined, with an increasing mean value (0.463–0.503), except in Chongqing municipality. The ESF decreased significantly (the mean value dropped from 44.7% to 38.7%), except that in Sichuan province. (2) The average CCD between ER and ESF decreased with fluctuation of −0.017, with a decoupling relationship (58.18%). The coupling area is larger than the decoupling area in the Sichuan area, while other provinces are opposite. (3) The coupling/decoupling relationship in the study area is mainly driven by terrain (elevation, slope) and socio-economic (population density, per capita GDP) factors. More attention should be paid to the role of these factors in the continuous reduction and control of ESF and ER. This study can serve as a reference for similar studies in karst regions, such as risk assessment and surface monitoring, rocky desertification control, ecological engineering layout, and territorial planning.

Comparison of phase-change-heat-pump cooling and liquid cooling for PEM fuel cells for MW-level aviation propulsion

Proton exchange membrane fuel cells (PEMFCs) are seen a key player in the sustainable and clean aviation transition. They can supply the main mega-watt (MW) level electric power aboard with many advantages. To notably increase their system specific power, a new phase-change-heat-pump (PCHP) cooling strategy is proposed and compared with the conventional liquid cooling through a model-based study. The comparison is carried out in terms of the induced drag power on a PEMFC-jet hybrid engine layout. The results reveal a drag reduction of 1.528 MW under the PCHP cooling, which accounts for about 16% of the aircraft's net cruise power. This saving is mainly from the minimized capacity of the heat exchanger between the PEMFCs and ambient. Besides, the ramjet effect also contributes significantly in the drag reduction. Last but not least, the optimal operating current density of the PEMFCs under PCHP cooling is brought up by about 26.5%.

Dynamic cylinder deactivation: Thermodynamic mapping for the case of stoichiometric SI ICE

Conventional cylinder deactivation has been improving internal combustion efficiency for decades. It provides benefits for any internal combustion engine, particularly engines with high number of cylinders. The level of engine displacement reduction depends on the number of cylinders that may be deactivated during operation. This limits the potential benefit. Theoretically, maximum benefit of cylinder deactivation would require assignment of specific displacement reduction to each engine operating point. Dynamic cylinder deactivation is a new approach, which does not continuously deactivate cylinders, but deactivates selected engine cycles. This allows to dynamically reduce engine displacement and to assign optimum displacement reduction to each operating point. The paper deals with the one-dimensional thermodynamic simulation of the dynamic cylinder deactivation applied to a small displacement four-cylinder gasoline engine, points out crucial attributes of this new approach and compares it with baseline engine layouts and with the conventional cylinder deactivation as well. The research concludes that the dynamic cylinder deactivation improves the fuel consumption for engines loads BMEP < 5 bar. Deactivation strategy with the lowest trapped mass value in the deactivated cycle shows the most benefit.

HEAT EXCHANGER STUDY AND OPTIMIZATION APPROACH FOR ENGINE EFFICIENCY IMPROVEMENT

The scenario for the off-road machines during the next years will feature vehicles with relevant changes in terms, for example, of engine operative velocity and passive braking force reduction, with a concurrent increase (some 40 %) of thermal energy exchange needs by the heat exchanger. Engine, and hydraulic oil, temperatures will vary in function of actual requested power, to reduce the NOx production. This aspect, linked to the need to have an optimized engine layout (reduction of radiator dimensions) is the base of the work presented in the paper. The heat exchanger optimization is needed to obtain smaller, lighter, but at the same time more efficient, heat exchangers; this paper shows how it is possible to apply a CFD-mathematical approach on a cross-flow radiator with the aim to obtain a more efficient heat exchanger surface and reduced global dimensions. The approach used, and described in this work, made the performance evaluation possible not only on a single radiator, but on a complete production family variable both in dimension and technical characteristics. The approach is to split the exchanger into sub-domains having homogeneous boundary conditions, both in the cold and hot side, in order to collect on the WHTC (Wall Heat Transfer Coefficient) and the pressure drop. Individual results will be used as building blocks in order to have a reliable yet flexible estimate of the exchanger performance under different environmental conditions and dimensions. The results are encouraging and show the possibility to develop a new, optimized, radiator family, using a flexible and efficient design strategy. Keywords: heat exchanger, earth moving machineries, engine efficiency, optimization approach.