Engine Intake Air Research Articles

Experimental Dust Absorption Study in Automotive Engine Inlet Air Filter Materials.

The purpose of this study was to empirically evaluate the performance of fibrous materials that meet the criteria for inlet air filtration in internal combustion engines. The characteristics of filtration efficiency and accuracy, as well as the characteristics of flow resistance, were determined based on the mass of dust accumulated in the filter bed during the filtration process. Single-layer filter materials tested included cellulose, polyester, and glass microfiber. Multilayer filter media such as cellulose-polyester-nanofibers and cellulose-polyester were also examined. A new composite filter bed-consisting of polyester, glass microfiber, and cellulose-and its filtration characteristics were evaluated. Utilizing specific air filtration quality factors, it was demonstrated that the composite is characterized by high pre-filtration efficiency (99.98%), a short pre-filtration period (qs = 4.21%), high accuracy (dpmax = 1.5-3 µm) for the entire lifespan of the filter, and a 60-250% higher dust absorption coefficient compared to the other tested materials. A filtration composite bed constructed from a group of materials with different filtration parameters can be, due to its high filtration efficiency, accuracy, and dust absorption, an excellent filter material for engine intake air. The composite's filtration parameters will depend on the type of filter layers and their order relative to the aerosol flow. This paper presents a methodology for the selection and testing of various filter materials.

Identification of User Requirements and their Influencing Factors Based on Online Reviews and Operational Data

It is crucial for enterprises to clearly identify user needs during the process of formulating product design improvement plans. Therefore, it is essential to comprehensively and accurately identify user needs, explore the reasons behind the emergence of these needs, and incorporate user opinions into the process of product design improvement. A method is proposed to comprehensively and accurately capture user requirements and address the challenge of identifying the underlying causes of user requirements. This method utilizes online comments and operational data to identify user requirements and their influencing factors. First, text sentiment analysis techniques are employed to quantify the importance and performance values of product feature topics. Second, we construct a quadrant model to identify product features requiring improvement, and the original negative comments related to these features are traced. However, the quadrant model alone is insufficient to reflect specific product issues that users are concerned about. Therefore, a functional structure model based on product issues is designed to filter and identify factors that influence user requirements using operational data. Finally, a Bayesian network inference approach is utilized to identify the key influencing factors on user requirements, enabling analysis of the causes behind user requirements and the proposal of product design improvement strategies. The feasibility and effectiveness of the proposed method are validated through experiments conducted on heavy-duty truck data. By analyzing the original negative comments related to the power characteristics, specific user demands regarding the insufficient power of the product were identified, such as “obviously insufficient power when climbing slopes” and other issues. Based on the vehicle power system functional structure model, combined with expert knowledge and operational data, factors related to the state of parts and user behavior that may affect “insufficient vehicle power” were identified. Based on the analysis results, suggestions were made to improve the engine intake air temperature control strategy and to enhance vehicle performance by promoting correct user behavior through informational campaigns.

Effect of Air Intake Temperatures on the Air-Water Harvester Performance

During the dry season, some parts of Indonesia experience drought and a clean water crisis, resulting in scarcity and difficulty in drinking water. One of the solutions to solve this problem is to use an air-water harvester machine that produces water from the air. Since the intake air temperature affected the water yield, the article examined the relationship between the engine intake air temperature and the machine’s performance. The study aimed to determine the performance of the air-water harvester machine at various air intake temperatures. The research was carried out experimentally for a refrigerant working fluid R134a. The rotary-type 1/4 PK compressor was used to realize the research. The air temperatures entering the condensing unit varied between 30, 35, and 40 °C. The results showed that the highest average water mass obtained was 0.34 kg at a temperature variation of 30 °C. The highest total heat absorbed by the condensing unit from the air of 184 W occurred at a temperature variation of 40 °C. Overall, an increase in the air intake temperatures allowed for a decrease in the performance of the air-water harvester machine by more than 5 %.

Assessment of a methanol-fueled integrated hybrid power system of solid oxide fuel cell and low-speed two-stroke engine for maritime application

An integrated solid oxide fuel cell (SOFC)-internal combustion engine (ICE) system was proposed in this paper. Methanol was used as the fuel in the system, meaning that the SOFC exhaust gas could not enter the engine with methanol, due to the high-injection pressure of fuel in engine and difficulty of pressurizing SOFC exhaust gas. Therefore, this paper proposed SOFC exhaust gas was delivered with engine intake air to achieve waste gas reutilization, which could also reduce oxygen concentration and increase specific heat capacity of in-cylinder gas for low NOx emissions. Two modes were proposed, including delivering SOFC anode-off gas into engine for Tier II requirements and delivering SOFC cathode and anode off gas into engine for Tier III requirements. The effects of power ratio of SOFC and engine on proposed system were analyzed based on the electrochemical model of SOFC and filling and emptying model of engine. The results indicated that increasing the power ratio in both modes led to an increase in brake power but a decrease in indicated efficiency, mainly due to the increase in energy input and the decrease in exergy-to-power conversion efficiency. In addition, at Tier III mode, the Tier III requirements (weighted average NOx was 3.35 g/kWh) were met at power ratio of around 1:2, at which the energy and exergy efficiency of system reached 55.6% and 57.9%. Furthermore, an improvement for a tanker was proposed, substituting proposed system for combination of marine engine and diesel genset. Specifically, SOFC and ICE were used for auxiliary power unit and propulsion, respectively. The results showed that it could achieve better carbon-emission and techno-economic performances. The payment period of such improvement was 3.08 years taking carbon trading and government support into account.

Optimizing model parameters of artificial neural networks to predict vehicle emissions

This paper presents a novel approach to predict carbon dioxide (CO2), nitrogen oxides (NOx), and carbon monoxide (CO) emissions of diesel vehicles using artificial neural network (ANN), which offer high degrees of accuracy and practicality. Six operating parameters (velocity, engine speed, engine torque, engine coolant temperature, fuel/air ratio, and intake air mass flow) collected through on-board diagnostic interface were used as predictors of exhaust emissions. The importance of each parameter to the emission predictions were comprehensively analyzed by comparing the coefficient of determination, root mean square error, cumulative emissions, and instantaneous emission rates. The emission prediction accuracy of ANN tends to increase as more parameters were considered as model inputs at the same time. However, the level of accuracy improvement depends on the input parameters. For CO2 emissions, engine torque and fuel/air ratio were good predictors for achieving high prediction accuracy. The relative importance of intake air mass flow rate and fuel/air ratio was high for NOx and CO predictions, respectively. In addition, the emission prediction accuracy of ANN depends on the vehicle type (Euro 5, Euro 6b, Euro 6d-temp). The emission prediction accuracy of vehicles equipped with after-treatment devices (selective catalytic reduction and lean NOx trap) was lower than that of vehicles without after-treatment devices.

Cooling Potential of Ship Engine Intake Air Cooling and Its Realization on the Route Line

A fuel efficiency of a ship engine increases with cooling inlet air. This might be performed by the chillers, which transform the heat of engine exhaust gas and scavenge air for refrigeration. The effect gained due to cooling depends on the intake air temperature drop and the time of engine operation at decreased intake air temperature. Thus, the cooling degree hour (CDH) number, calculated as air temperature depression multiplied by the duration of engine operation at reduced intake air temperature, is used as a primary criterion to estimate the engine fuel efficiency enhancement due to intake air cooling over the ship routes. The engine intake air cooling potential is limited by its value, available according to engine exhaust heat and the efficiency of heat conversion to refrigeration in the chiller, evaluated by the coefficient of performance (COP). Therefore, it should be determined by comparing both the needed and available values of CDH. The ejector chiller (ECh) was chosen for engine exhaust gas heat recovery to refrigeration as the simplest and cheapest, although it has a relatively low COP of about 0.3 to 0.35. However, the ECh generally consists of heat exchanges which are mostly adapted to be placed in free spaces and can be mounted on the transverse and board side bulkheads in the ship engine room. The values of sucked air temperature depression and engine fuel consumption reduction at varying temperatures and humidity of ambient air on the route were evaluated.

A novel degree-hour method for rational design loading

Cooling degree-hours (CDH) received the broadest application in evaluation of the ambient air cooling efficiency in power engineering (engine intake air cooling systems) and air conditioning. The current CDH numbers are defined as a drop in air temperature multiplied by associated time duration of performance and their summarized annual number is used to estimate the annual effect achieved due to sucked air cooling in power plants based on combustion engines (fuel saving, power output increment) and in air conditioning (refrigeration energy generation according to needs). A majority of approaches to designing ambient air cooling systems is proceeding from the cooling capacity of the chillers selected to provide a maximum current or annual CDH number with corresponding maximum current or annual effect (additional energy produced or fuel consumption reduction) in site climate location. But such approaches lead to inevitable oversizing the chillers and cooling systems in the whole. The analysis of intake air cooling efficiency in site varying climatic conditions, accompanied by quite a simple numerical simulation, enabled to reveal the potential of its enhancement and evaluate numerically the results of each step of designing in logical sequence. The new approaches to cooling system rational designing were introduced, that enables to synthesize and substantiate innovative principal decisions to exclude unproductive waste of installed (design) cooling capacity in actual operation. The innovative findings of methodological approaches include the use of the rate of annual CDH number increment as an indicator for selecting the optimum and rational values of design cooling capacity. The optimum cooling capacity corresponds to maximum rate of summarized annual CDH increment and maximum level of thermal loading accordingly, which provides minimum sizes of the chiller. In reality, it is a minimum permissible value of cooling capacity of the chiller installed and the overall ambient air cooling system. The rational cooling capacity, that enables to achieve practically maximum value of annual CDH and avoid chiller oversizing, is determined as the second, local, maximum of the rate in the summarized annual CDH over the range above the first one, global, maximum. A rational design cooling capacity determined by applying the novel methodology allows to decrease the ambient air cooling system sizes by 15 to 20% compared with traditional designing issuing from the peaked thermal load during a year. With this practically a maximum annual effect in fuel saving (energy generation or others) can be achieved too.

Experimental Studies of PowerCore Filters and Pleated Filter Baffles.

The material most commonly used to filter and clean the intake air of vehicle internal combustion engines is pleated filter paper, which in most cases is shaped in the form of a cylinder or panel. The production technology has a low cost and is not complicated. In addition to high separation efficiency and filtration performance, pleated filter media are required to have low initial pressure drop, which depends on the geometry of the bed. Much research has been conducted in this area. Dust accumulated in the filter bed causes an increase in pressure drop, which is the cause of deformation and sticking of pleats. The lack of stability of the pleats, the need to strengthen them, and the need to obtain small sizes while achieving high efficiency and accuracy of filtration of engine intake air was the reason for the development of a different design and a new technology for making filter cartridges called PowerCore. The distinctive feature of these filters is axial flow in one direction of the air stream, which avoids turbulence and thus minimizes pressure drop. This paper presents a comparative analysis of a standard PowerCore and PowerCore G2 filter bed and two cylindrical filters with a pleated filter bed made of cellulose and polyester. The conditions and methodology of experimental testing of filters with test dust are presented. During the tests, the characteristics of separation efficiency and filtration performance, as well as pressure drop as a function of the mass of dust retained on the filter of two PowerCore filters and two cylindrical filters were performed. Three specimens of test filters with the same filtration area were made from each sample of filter bed. The results showed that in each test of the filter bed, there is an initial filtration period characterized by low (96–98%) initial separation efficiency and the presence of large (dpmax) dust grains. As the dust loading of the bed increases, the separation efficiency and filtration performance obtain higher and higher values. The initial period of filtration ends when the conventional value (99.9%) of separation efficiency is reached. The duration of this period depends on the type of filter bed and for the PowerCore G2 filter ends for a dust loading of km = 33.1 g/m2, and for the cellulose filter for km = 117.3 g/m2. During the initial period, the air behind the PowerCore G2 filter contains grains with sizes in the range of dpmax = 9–16 µm. Behind the cellulose filter, dust grains are much larger, dpmax = 17–35 µm. The total operating time of the PowerCore G2 filter, limited by the achievement of the permittivity resistance Δpwdop = 3 kPa, is twice that of the other filter compositions tested.

Development of a phenomenological model for the description of RCCI combustion in a dual-fuel marine internal combustion engine

Increasingly stringent pollutant and CO2 emission standards require engine manufacturers to investigate innovative solutions. Among these techniques, low-temperature combustion (LTC) concepts have a large potential to simultaneously reduce NOx emissions and fuel consumption. A promising manner to realize LTC consists of adopting ultra-lean mixtures, where the combustion evolution is controlled by a proper spatial distribution of fuels with different chemical reactivities. In this context, depending on the proportion and stratification of the fuels, the heat release can primarily depend on chemistry progression, leading to a Reactivity Controlled Compression Ignition (RCCI) mode, or on flame propagation, locally initiated by a high reactivity fuel.In this work, the combustion characteristics of a large-bore research engine are experimentally investigated. Natural gas is supplied into the intake port, while light fuel oil (LFO) is directly injected in the cylinder. An experimental campaign is carried out including sweeps of engine load, air/fuel proportion, LFO amount, valve timing, and intake air temperature. Global engine operating parameters as well as cylinder pressure traces are recorded and analyzed.Based on the available experimental data, a phenomenological model handling both chemistries of fuels with different reactivities and flame propagation is developed and validated. The model is based on a multi-zone approach, where auto-ignition chemistry is solved by a tabulated method to preserve the computational effort. The proposed numerical approach shows the ability to simulate the experimental data with good accuracy, using a fixed tuning constant set. A dedicated correlation is built to reproduce the expected in-cylinder distribution of the directly injected liquid fuel. Global performance and combustion parameters are predicted with an average error below 5%. The model demonstrates to correctly describe the behavior of the tested engine under different operating conditions and to capture the physics behind such advanced combustion concepts.

Composite nonwoven filter media with hierarchically arranged fibres of different geometries for automotive engine intake air filtration

This paper reports the development, characterization, and performance assessment of a series of promisingly designed nonwoven air filter media for automotive engine intake application. Commercially available fibres are processed through a laboratory-based needle-punched nonwoven line to prepare a plurality of composite nonwoven filter media with hierarchically arranged fibres of different sizes or shapes. The filter media are then assessed for their dynamic filtration performance both at cleaned and clogging states by employing testing devices based on gravimetric measurement and particle counting technologies. The composite nonwoven filter media with hierarchically arranged fibres of different geometries display excellent filtration performance and are found to be very promising for commercial engine application. As compared to their homogeneously-mixed counterparts, the composite nonwoven filter media offer higher gravimetric as well as fractional filtration efficiency, higher dust holding capacity, and more delayed rise of pressure drop.

Microstructure and particle filtration behavior of multimodal fibrous filter media made of fibres of different sizes for engine intake air filtration

This paper reports a set of theoretical expressions for describing the microstructure of multimodal fibrous filter media comprising fibres of different cross-sectional sizes along with the application of such expressions to predict the filtration performance of clean and clogging media for engine intake air filtration. It is found that the overall filtration efficiency corresponds very well with the classical theory of air filtration after suitably modifying the single fibre efficiency and mean fibre diameter. The square of mean fibre diameter is found to be a weighted harmonic mean of the square of fibre diameter of individual component. The single fibre efficiency of multimodal filter media, when expressed as a summation of single fibre efficiencies of individual component of fibres weighted by the corresponding surface area fraction, correlates very well with the experimental results. The evolution of pressure drop is explained satisfactorily based on Berman’s approach after suitably modifying the Davies equation.

Energy Saving in Trigeneration Plant for Food Industries

The trigeneration plants for combined cooling, heating, and electricity supply, or integrated energy systems (IES), are mostly based on gas reciprocating engines. The fuel efficiency of gas reciprocating engines depends essentially on air intake temperatures. The transformation of the heat removed from the combustion engines into refrigeration is generally conducted by absorption lithium-bromide chillers (ACh). The peculiarity of refrigeration generation in food technologies is the use of chilled water of about 12 °C instead of 7 °C as the most typical for ACh. This leads to a considerable cooling potential not realized by ACh that could be used for cooling the engine intake air. A refrigerant ejector chiller (ECh) is the simplest in design, cheap, and can be applied as the low-temperature stage of a two-stage absorption-ejector chiller (AECh) to provide engine intake air cooling and increase engine fuel efficiency as result. The monitoring data on gas engine fuel consumption and power were analyzed in order to evaluate the effect of gas engine cyclic air cooling.

Liquid-mediated particle capture by nonwoven filter media for automotive engine intake air filtration

This article reports on development, characterization, and performance of liquid-treated nonwoven air filter media for automotive engine intake application. A polypropylene fiber-based needle-punched nonwoven fabric was prepared for treatment with four viscous liquids (glycerol, SAE 20W/50 engine oil, PEG 400, and deionized water) by liquid spraying technique. The filtration performance was evaluated in terms of initial and final gravimetric filtration efficiencies, fractional filtration efficiency, evolution of pressure drop, and dust holding capacity. The liquid-treated filter media registered higher gravimetric as well as fractional filtration efficiency and higher dust holding capacity as compared to the untreated ones. The initial and final gravimetric filtration efficiencies were found to be directly related to liquid add-on via a power law relationship. The liquid-treated filter media also exhibited higher fractional filtration efficiency than their untreated counterparts for all sizes of tested particles. Interestingly, the increase of fractional efficiency was more for smaller particles as compared to larger ones. This was explained quantitatively through single fiber efficiency due to adhesion. The viscosity of liquid was found to be a very crucial parameter as the dust deposition morphology was contingent to the flow of liquid onto the filter media. The stickiest liquid yielded highest filtration efficiencies, displayed slowest rise of pressure drop, and exhibited highest dust holding capacity.

Efficient waste heat recovery system for diesel engines using nano-enhanced phase change materials

Cold start is one of the most difficult combustion phases of a diesel engine; and a large percentage of pollutants are produced during this period. Therefore, the present study focuses on proposing a numerical investigation of a novel design of an air preheating system to warm up the engine intake air at ambient air temperatures of 273 and 268 K. The preheating system consists of nano-enhanced phase change materials (NEPCM) housed in a plate heat exchanger. A comprehensive thermal model was developed and validated using experimental data from the literature. The model couples the transient turbulent fluid flow of the engine exhaust gases with the melting and solidification processes in the NEPCM domain. The effect of nanoparticle type, nanoparticle weight fraction, engine rotational speed, and ambient temperature were investigated. At 2000 rpm, the charging time was reduced by 34.88%, 30.23%, and 25.58% when using 5 w.t% of SiO2, Al2O3, and CuO nanoparticles, respectively. During the discharging process, in less than 1 min, the cold intake air can be heated from ambient temperatures of 273 and 268 K to 301.8 and 300.6 K, respectively.

Assessing the addition of hydrogen and oxygen into the engine's intake air on selected vehicle features

Road transport has a significant effect on air pollution. Therefore, the article focuses on the impact of addition of “oxyhydrogen”, known as HHO, on selected vehicle features. These features, on which this study is focused, include the engine power and torque, composition of the exhaust gases and fuel consumption. There was also an impact of HHO on the value of pre-ignition as well as engine cleaning observed. HHO has been obtained from the generator designed and constructed for the purposes of this article. The measurements were performed under conditions of taking electric energy needed for HHO operation from the vehicle used in the measurements and also from the other source. The measurements were performed with vehicles of different kilometres driven, different technical conditions and different fuels and they were conducted under laboratory conditions to ensure a higher accuracy of the results. The results have shown a low impact of HHO addition of 2 dm3 min−1 on concentration of particular components of the exhaust gases. With HHO added, it was measured a mild decrease in the engine power and torque. Taking electric energy needed for HHO operation from the vehicle used in the measurement has evinced more considerably than addition of HHO into the engine.

Problems of selecting filter partition in passenger car engine intake air filters

The aim of this study was to verify the criteria for selecting pleated filter partitions used in passenger car engine filters. The paper presents the problem of optimizing pleated air filters in the dir ection of minimizing pressure drop, which is the source of engine energy losses. Two criteria for selection of a paper filter partition for specific operating conditions of the filter and the engine are presented: criterion of permissible separation speed and criterion of permissible pressure drop. The actual filtration area of 44 paper pleated filter elements used in passenger cars and the air stream flowing through the filter were determined, which made it possible to calculate separation speed. In 62% of the analyzed filter inserts, the calculated separation speeds are within the speed range recommended by the constructors, Fmax = 0,06-0,12 m/s. Exceeding permissible separation speed Fmax = 0,12 m/s was found mainly in supercharged engines. Negative effects of engine operation with an air filter with too small separation area are presented, in the form of increased pressure drop and energy loss of the engine as well as shorter car mileage to reach permissible pressure drop.

Application of oxygen enrichment and adiabatic humidification to suction air for reducing exhaust emissions in a gasoline engine

ABSTRACT This paper aims to reduce the exhaust emissions of a gasoline engine by conditioning the engine intake air. The oxygen enrichment of inlet air to reduce the HC and CO emissions and humidifying the inlet air to control NOX emissions was applied. The intake air oxygen concentration was increased from 21% to 25% by 2% interval. The oxygen enrichment of the engine inlet air increased the combustion rate, and thus combustion improved, and thermal efficiency increased. This situation led to a reduction in HC emissions and CO emissions. However, the combustion improvement caused a striking rise in NOX emissions because of the high cylinder temperature and high oxygen concentration. This undesirable effect was tried to be alleviated by adiabatic humidification of the engine inlet air. For this purpose, the relative humidity of the intake air was increased from 35% to 65% before and then to 85%. For this, the intake air passed through the conditioning chamber, the dry thermometer temperature lowered by 4 °C for a relative humidity of 85% thanks to the evaporative cooling of water. The results showed that oxygen enrichment caused a 13.5% and 9.3% increase in thermal efficiency in order of half and full load. The humidification method resulted in a 14.3% and 18.3% decrease in thermal efficiency for half and full load. The results also showed that the humidification method could only control NOX increment generated at half load and 23% oxygen condition.

Effect of Refrigeration Assisted Intercooler Turbocharging on Engine’s Horse Power

The stringent regulations on fuel saving and emissions reduction in the transportation sector have become game-raisers in the development of present internal combustion engines for road applications, even if under-the-hood space constraints, downsizing and down-weighting prevent from adopting radical changes in the engine layout. In current research, objective is to find a viable and pragmatic solution to reduce the turbo-charged engine intake air temperature by a large value as compared to traditional air-to-air intercoolers to increase Engine Horsepower. In undergoing research, a refrigerated intercooler is designed on the basis of refrigeration cycle, which further decreases the intake air temperature of the engine, resulting in increased horsepower, and improved Formula 1 lap times. Additionally, Formula 1, 2014 (V6 Turbo-Charged) Engine is used. According to the results, horse power of 1209.74HP is obtained by using refrigeration assisted intercooler. However, 1061HP is obtained for air to air intercooler. So, performance gain of 15 to 20% over present intake air cooling system in Formula 1 engine cars is successfully achieved. Additionally, Research will be utilized to decrease lap time in formula 1 racing cars.

Cooling intake air of marine engine with water-fuel emulsion combustion by ejector chiller

The fuel efficiency of cooling air at the inlet of marine low speed diesel engine with water-fuel emulsion combustion by ejector chiller utilizing the heat of exhaust gas along the route line Mariupol– Amsterdam–Mariupol was estimated. The values of available refrigeration capacity of ejector chiller, engine intake air temperature drop and corresponding decrease in specific fuel consumption of the main diesel engine at varying climatic conditions along the route line were evaluated. Their values for water-fuel emulsion were compared with conventional fuel oil combustion.

Innovative combined in-cycle trigeneration technologies for food industries

The majority of integrated energy systems (IES) for combined electricity, heat and refrigeration generation, or trigeneration, are based on gas engines. The fuel efficiency of gas engines are strictly influenced by intake air temperatures. Practically in all IES the absorption lithium-bromide chillers (ACh) are applied for conversing the heat removed from the engine into refrigeration in the form of chilled water. The peculiarity of trigeneration in food industries is the use of chilled water of about 12°C for technological needs instead of 7°C as typical for ACh. This leads to a considerable great potential of engine intake air deeper cooling not realized by ACh, that can be used by ejector chiller (ECh) as the low temperature stage of two-stage absorption-ejector chiller (AECh) to provide engine cyclic air deep cooling and enhancing engine fuel efficiency. To evaluate the effect of gas engine cyclic air cooling the data on fuel consumption and power output of gas engine JMS 420 GS-N.L were analyzed.