Intake Air Temperature Research Articles

Effect of Intake Temperature and Engine Speed on the Auto-Ignition Reactivity of the Fuels for HCCI Fuel Rating

<div class="section abstract"><div class="htmlview paragraph">The current research octane number (RON) and motor octane number (MON) gasoline tests are inadequate for describing the auto-ignition reactivity of fuels in homogeneous charge compression ignition (HCCI) combustion. Intake temperature and engine speed are two important parameters when trying to understand the fuel auto-ignition reactivity in HCCI combustion. The objective of this study was to understand the effect of high intake temperature (between 100 and 200 °C) and engine speed (600 and 900 rpm) on the auto-ignition HCCI reactivity ratings of fuels using an instrumented Cooperative Fuel Research (CFR) engine. The fuels used for this study included blends of iso-octane/n-heptane, toluene/n-heptane, ethanol/n-heptane, and gasolines with varying chemical compositions and octane levels. The CFR engine was operated at 600 and 900 rpm with an intake pressure of 1.0 bar and an excess air ratio (lambda) of 3. It was found that the relative HCCI reactivity ranking of the gasolines with a RON of 98 was constant at both engine speeds and high intake temperatures (150 °C and 200 °C). This implied that for HCCI fuel ratings, there exists a threshold intake temperature beyond which further increases in temperature do not change the relative rankings of the fuel’s HCCI reactivity. At these high intake air temperatures, changes in engine speed between 600 and 900 rpm did not affect the HCCI ratings of the RON98 gasolines either. However, the effects of intake temperature (between 150 and 200 °C) and engine speed (600 and 900 rpm) did become apparent when additional gasoline octane levels and chemical compositions were investigated.</div></div>

Experimental investigation of strategies to enhance the homogeneous charge compression ignition engine characteristics powered by waste plastic oil

In the present-day scenario, the regulations over vehicle emissions are highly stringent, and the manufacturers are struggling to satisfy the emission norms. Waste plastic oil (WPO) powered conventional compression ignition (CI) engine discharge higher oxides of nitrogen emission. The utilization of WPO as a sole fuel in homogeneous charge compression ignition (HCCI) engine would satisfy both energy demand and emission norms. The present study demonstrates the effects of different intake air temperatures (IAT) and injection pressures (IP) of WPO on the HCCI engine’s performance and combustion characteristics. The results revealed that the WPO fueled CI engine showed greater BTE when correlated to WPO powered HCCI engine. In the HCCI mode of operation, the elevated IAT led to the advanced start of combustion (SOC). It shortened the combustion due to an increase in post-combustion temperature and cylinder pressure. WPO operated homogeneous charge mode with IAT of 90 °C resulted in better BTE and lesser unburnt hydrocarbon (UBHC), smoke, and carbon monoxide (CO) emission than IAT atmospheric conditions. The HCCI engine with elevated IAT of 80 °C, 90 °C, and 100 °C drastically reduced the NOx emission by 45.5%, 41.9%, and 40.04% than standard CI engine fueled with WPO+- respectively. Among various IPs of WPO, IP of 8 bar revealed 3.08% higher BTE with 11.2%, 16.6%, 14.7% decrease in CO, UBHC, and smoke emission, respectively. At the optimum condition of IP and IAT in the HCCI engine, the BTE was closer to that of the WPO powered CI engine, and also ultra-lean NOx and smoke emissions were noticed.

Implementation and Parameter Analysis of the Knock Phenomenon of a Marine Dual-Fuel Engine Based on a Two-Zone Combustion Model

The stable working window of a dual-fuel engine is narrow, and it is prone to knock during operation. The occurrence of knock limits the load and torque output of a dual-fuel engine, and even causes engine damage in severe cases. The existing volumetric model of marine dual-fuel engine has little research on the related problems of knock simulation. In order to analyze the causes of knock phenomenon and the influence of operating parameter changes on knock, under the Matlab/Simulink simulation environment, a quasi-dimensional model was established with MAN 8L51/60DF dual-fuel engine as the prototype, and the model was calibrated using the bench data. The knock intensity index coefficient (KI) was used as the evaluation index of knock intensity. Three parameters, the intake air temperature, compression ratio, and natural gas intake, were selected as variables to simulate the engine. According to the analysis of the simulation results, the influence of the parameter changes on the occurrence of engine knock phenomenon and knock intensity could be further studied. The results showed that the combination of the KI model and the quasi-dimensional model could effectively and accurately predict the engine performance and knock trend. The change of gas inlet quality, compression ratio, and inlet temperature could promote the occurrence of detonation, the engine knock could be avoided by controlling the intake air temperature below 336 K, compression ratio not exceeding 15 or the intake volume of natural gas per cycle not exceeding 11.25 g/cycle.

Characteristics of NOx emission of light-duty diesel vehicle with LNT and SCR system by season and RDE phase

As the regulations on vehicle emissions have become more stringent internationally and real-driving emissions (RDE) have been established, the on-road characteristics of emissions have gained importance in vehicle research and development. The results of the fuel consumption levels and emissions from on-road tests are affected by many factors, such as driving conditions, routes and environmental conditions. Therefore, more research and analysis are needed for the effects of environmental factors and driving conditions according to RDE phase on the NOx emissions. In this study, RDE tests were conducted by season to analyze the on-road NOx emission characteristics of lean NOx trap (LNT)- and selective catalytic reduction (SCR)-equipped diesel vehicles corresponding to the Euro 6b regulation prior to the application of the RDE regulation. The purpose of this study is to analyze the effects of seasonal factors and phases of the RDE routes on the NOx emission and NOx conversion efficiency of catalyst. In spring/autumn and summer, the engine-out and tail-pipe NOx emissions were higher 1.3–5.9 times for vehicle A and 1.3–28.4 times for vehicle B in the urban phase than in other phases. In the urban phase, the engine bay temperature was probable to rise owing to frequent stops and low-speed driving, leading to a high intake air temperature, which causes excessive NOx emission, particularly in summer. The average air filter temperature in urban phase was 11–15 °C higher than the environment temperature for vehicle A. The NOx conversion efficiency of the LNT was highest at 54.1% on motorway and the efficiency was dependent on the phase of the test route. The NOx conversion efficiency of the SCR, which is dependent on the catalyst temperature, was highest at 98.7% in spring motorway and the efficiency was affected by the combined factors of season and phases.

Influence of butanol addition on the CI engine performance fuelled with treated waste engine oil

ABSTRACT Treated waste engine oil can be utilized as compression ignition fuel. An experimental study has been performed to overcome the limitations in fueling treated waste engine oil into diesel engine as fuel, by the addition of butanol, modification of nozzle opening pressure, fuel injection timing, and intake air temperature. Butanol (0-50% by volume) was blended with treated waste engine oil and tested for properties and the found properties were compared to diesel. Butanol used was produced from vegetable waste by recycling. This blend was tested in a direct injection compression ignition engine for various load conditions by modifying the engine operating parameters such as nozzle opening pressure, fuel injection timing, and intake air temperature for performance. The optimal level of these parameters (210 bar of nozzle opening pressure, 29ᵒ before the top dead center of fuel injection timing, and 100ᵒ C of intake air temperature) to fuel 50% treated waste engine oil and 50% butanol and were obtained by using the L9 orthogonal array and the Taguchi method. The brake thermal efficiency, ignition delay, emissions of smoke, and oxides of nitrogen produced by this blend was found to be closer to that of diesel at rated power condition.

모듈러 데이터센터 냉각시스템의 취출온도 조건에 의한 연간에너지 소비량 예측

The modular data center is greatly influenced by operating conditions because its internal size is smaller than the existing hyperscale data center. The recent emergence of servers that can adapt well to indoor temperature rise requires a review of existing temperature conditions. In this study, the potential for temperature condition mitigation and annual energy performance were analyzed for recent installations of improved thermal performance servers in container-type distributed modular data centers. According to the analysis, the upper dry bulb temperature of the intake air for maintaining the recommended level, acceptable level A1, and acceptable level A2 was 14℃, 16℃, and 19℃ respectively. The annual energy savings predicted in the analysis was 3.1% and 9.2%, when the intake air temperature of the servers in the modular data center was mitigated to the A1 and A2 levels respectively.

Flow and conjugate heat transfer with surface radiation characteristics of a real-scale infrared suppression device with conical funnels

The precise flow and heat transfer aspects in an infrared suppression (IRS) device are challenging because of the complicated flow features. The suction of cold ambient air and subsequent mixing with the hot exhaust gas from the turbine in cargo/naval ships happens in the IRS device. In the present research, the thermo-fluid characteristics of a two-dimensional axisymmetric IRS system consisting of conical funnels stacked one above the other are meant to study. Numerical simulations are performed for the real-scale IRS unit by solving the equations of mass, momentum, energy, and radiation in the computational domain surrounding the IRS device. In this study, the effect of conducting funnel walls with surface radiation is considered. The impact of the number of funnels on mass intake and the device outlet temperature is analyzed. The results show that the maximum air intake and minimum outlet temperature can be achieved using five funnels. The mass intake and device outlet temperature are also affected by funnel-overlapping and nozzle-overlapping. The maximum air intake and minimum outlet temperature are obtained by zero funnel-overlapping and zero nozzle-overlapping conditions. When the adiabatic funnel is replaced by conducting funnels with surface radiation, the increment in the mass intake and decrement in outlet temperature is observed. The impact of funnel wall inclination and the type of guide vanes are also discussed.

Theoretical investigation of the combustion performance of ammonia/hydrogen mixtures on a marine diesel engine

Ammonia is a good hydrogen carrier and can be well combined with hydrogen for combustion. The combustion performance of the mixtures of ammonia and hydrogen in a medium-speed marine diesel engine was investigated theoretically. The HCCI combustion mode was selected for reducing thermal-NOx production. The start fire characteristic of the NH3–H2 mixtures was studied under different equivalence ratio, hydrogen-doped ratio, and intake air temperature and pressure. Then, the combustion performance of the NH3–H2 mixtures (doping 30% hydrogen) was analyzed at a typical operation condition of engine. The addition hydrogen improved the laminar flame velocity of ammonia, and affected the NOx emission. For the medium-speed marine engine fueled with NH3–H2, reducing combustion temperature, introducing EGR and combining with post-treatment technology would be a feasible scheme to reduce NOx emission.

Development and Research of Crosshead-Free Piston Hybrid Power Machine

This article considers the development and research of a new design of crosshead-free piston hybrid power machine. After verification of a system of simplifying assumptions based on the fundamental laws of energy, mass, and motion conservation, as well as using the equation of state, mathematical models of the work processes of the compressor section, pump section, and liquid flow in a groove seal have been developed. In accordance with the patent for the invention, a prototype of a crosshead-free piston hybrid power machine (PHPM) was developed; it was equipped with the necessary measuring equipment and a stand for studying the prototype. Using the developed mathematical model, the physical picture of the ongoing work processes in the compressor and pump sections is considered, taking into account their interaction through a groove seal. Using the developed plan, a set of experimental studies was carried out with the main operational parameters of the crosshead-free PHPM: operating processes, temperature of the cylinder–piston group and integral parameters (supply coefficient of the compressor section, volumetric efficiency of the pump section, etc.). As a result of numerical and experimental studies, it was determined that this PHPM design has better cooling of the compressor section (decrease in temperature of the valve plate is from 10 to 15 K; decrease in temperature of intake air is from 6 to 8 K, as well as there is increase in compressor and pump section efficiency up to 5%).

Gasoline fuels properties for multi-mode operation – Observations in a GDI and the CFR engine

The combustion behavior of five full boiling range RON98 gasoline blends was evaluated for multi-mode operation in a GDI and the CFR octane rating engine. The GDI engine tests were conducted with stoichiometric air-fuel ratio in spark-ignition (SI), and with air-diluted homogeneous charge compression ignition (HCCI) mode. In the CFR engine, the knocking combustion was analyzed under standard RON testing conditions at both peak knocking lambda and stoichiometric air-fuel ratios, whereas compression ignited operation was characterized by utilizing the HCCI number test protocol. Disparate knock limited SI and HCCI combustion behavior was observed for the test fuels, despite four of the fuels having the same RON and octane sensitivity. It was found that knock-limited combustion phasing in the GDI engine did not align well with the RON. However, a detailed comparison of knock-limited SI operation in the GDI and CFR engine revealed that a more appropriate effective RON based on a common knock intensity metric (MAPO) and stoichiometric air-fuel ratio resulted in comparable knock characterization between the two engine platforms. Furthermore, the critical intake air temperature and the critical compression ratio were proposed to characterize knock-limited SI operation, while the minimum intake air heating and compression ratio were used to define a fuel’s autoignition propensity for compression ignition operation in the GDI and CFR engine, respectively. Finally, each fuel’s characteristic compression ratio needed to obtain knock-limited SI (KLSI) and HCCI operation was used to calculate an effective multi-mode octane number (MM-ON) based on the primary reference fuel blends.

Simulation of Palm Kernel Shell Gasification for Small Scale Power Generation Using Aspen Plus Software

In this study, a simulation flowsheet model of gasification process for small-scale power generation was developed in Aspen plus software in accordance with the actual 20-kW power pallet unit manufactured by All Power Labs Power Pallet. The flowsheet model is capable to determine the syngas composition and amount of power load generated from the internal combustion engine. Biomass feedstock used in the model was palm kernel shell as it possesses a favourable physiochemical property and easy to obtain. Proximate and ultimate analyses data were used as the basis for the flowsheet model to reflect the physical property of palm kernel shell as a non-conventional component. The gasification of palm kernel shell was simulated into four main processes which are drying, pyrolysis, combustion and reduction by using two R-Stoic models and individual R-yield and R-Plug model with specification of chemical reactions, dimensions and operating conditions of the process. The results obtained from the model were validated with experimental data of palm kernel shell gasification process at a similar operating temperature acquired from previous research studies. Several parameters such as gasification temperature, air preheating and pyrolysis temperature were studied under specified value subjected to the amount of power load generated. It can be seen that the gasification temperature, air preheating temperature and pyrolysis temperature were found to have a directly proportional trend on power load based on their respective temperature range. Furthermore, optimal power load (≈ 20 kW) can be generated at pyrolysis temperature of 460 °C with gasification and intake air temperature of 1200 °C and 550 °C respectively. This work is of significance for preliminary operational and plant design benchmark if the government is considering a large-scale development of biomass power generation.

Thermal performance of a fixed‐plate air‐to‐air energy recovery system for building application in hot and humid environment

An analysis of the performance of a fixed-plate air-to-air energy recovery system on its efficiency and recovered energy for potential building applications in the hot and humid environment was performed. Investigations were executed under controlled laboratory conditions in an energy testing chamber. Tests were carried out with varying operating parameters in terms of airflow rates that ranged from 1.0 to 3.0 m/s, intake air temperature of 28°C, 31°C, 35°C, 40°C and intake relative humidity of 70%, 75% and 80%. The performance was analysed by adopting the calculation methods of the ASHRAE Standard. This study showed that increased airflow rate decreased efficiency. The increase of airflow rate raised the recovered energy of the system. The study indicated that increasing values of intake air temperature (Tin) resulted in the increase of efficiency and recovered energy. A decrease in the efficiency of the system was observed, notably when the intake relative humidity (RHin) increased.

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.

EXPERIMENTAL INVESTIGATION OF FORCED EVAPORATION COEFFICIENT FROM THE DISTURBED SURFACE OF HEATED WATER

This article presents the results of laboratory tests of water evaporation for varying air velocities over the water surface at different water wave heights. Measurements of water evaporation were conducted using the experimental setup, which consists of a wind tunnel covering a bottom-heated water tank. The investigations were carried out for water temperature higher than the intake air temperature in the range of variable air velocity from 0.40 to 0.94 m/s. The measurements were carried out for four series with heights of spatter-free wave 0, 1.5, 3.0 and 5.0 mm, respectively. The conditions were maintained in such a way that the variations in the partial pressure over the water surface were kept to a minimum. The evaporation coefficient was defined, as the water mass transfer coefficient referred to the steady differential of water vapour partial pressures at air and water temperatures. The novelty consists in finding a linear correlation between the evaporation coefficient and the air velocity over the disturbed water surface. However, an increase in the evaporation coefficient is directly proportional to the height of the water wave. By comparing the wave height to the coefficient of pool occupancy, a new formula for predicting evaporation is given for indoor pools.

Performance investigations of cross flow indirect evaporative cooler

Dew point evaporative cooler is an indirect evaporative cooling (IEC) technique to lower temperature of incoming air below its wet bulb temperature and near to dew point temperature. The said technique does not involve any change in moisture content of incoming air. Performance parameters of dew point evaporative cooler are significantly influenced by configuration and structural arrangement of heat exchanger. The different arrangements of heat exchangers commonly used are counterflow, cross flow and counter-cross flow. This work presents performance investigations of cross flow indirect evaporative cooler. The cooling efficiencies and temperatures at the outlet of the cooler were investigated for different intake air temperatures and flow rates. Dew point evaporative cooling technique does not make use of compressor and harmful refrigerants hence would be a better option to conserve the environment and helps to reduce the emission of greenhouse gases.

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.

Performance investigation of regenerative evaporative cooled air-to-air heat recovery ventilator under different humidity conditions

To enhance the energy efficiency of an air-conditioning system air-to-air plate heat recovery ventilator can be installed to utilise the exhaust air for sensibly cooling of the ambient air. This pre-cooled intake air under low moisture content can be further cooled with a regenerative evaporative cooler. Therefore, an experimental investigation was conducted by fabricating a combined air-to-air heat exchanger and regenerative evaporative cooler test rig. The performances under low and high humidity were evaluated. Under low humidity, air-to-air heat exchanger works as sensible heat recovery ventilator, and under high humidity, it works as a dehumidifier for the regenerative evaporative cooler. The dynamic performance during the transition in humidity conditions and steady performance were studied. The results showed that the temperature below the wet-bulb temperature of intake air is achieved under low humidity. Under high humidity, condensation takes places for the intake air, increasing the latent cooling and decreasing the sensible cooling. Minimum temperature and humidity ratio of 19.9 °C and 17.05 g/kg were obtained respectively.

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.

ВПЛИВ ПІДІГРІВУ ПОВІТРЯ НА ВПУСКУ НА ЕНЕРГЕТИЧНІ ТА ЕКОЛОГІЧНІ ПОКАЗНИКИ ТРАНСПОРТНОГО ДВИГУНА ПРИ РОБОТІ НА СПИРТОВМІСНОМУ БЕНЗИНІ В УМОВАХ НИЗЬКИХ ТЕМПЕРАТУР

The article discusses the issue associated with the influence of air heating at the intake on the fuel efficiency and environmental performance of an engine with a carburetor power system when using alcohol-containing gasoline with a bioethanol content of about 36%, in the cold start, warm-up and idle modes. The use of inlet air heating is one of the promising areas for the implementation of energy-efficient technologies in road transport. The object of experimental research is a ZAZ-1102 car with a MeMZ-245 gasoline engine with a carburetor power system. The purpose of the work is to determine the effect of air heating at the intake on the energy and environmental performance of a transport engine when operating on alcohol-containing gasoline at low temperatures. The research method is experimental. As a result of the research, it was found that the use of air preheating at the intake with TAPP when using alcohol-containing gasoline with a bioethanol content of about 36% allows for reliable start-up while reducing the engine start-up time; reduce engine warm-up time by 15.8%, total fuel consumption by 34.6%; CO concentration at the beginning of heating decreases by 30.8%, CmHn concentration decreases 4.8 times. 120 seconds after warming up, the CmHn concentration when the engine is running without heating is 730 ppm, and with heating it is 370 ppm. CO concentrations are reduced from 0.37% to 0.25%. To ensure the adaptation of existing engines with a carburetor fuel supply system to the use of alcohol-containing gasolines with a bioethanol content of more than 20%, it is recommended at low temperatures to ensure an intake air temperature within 40 ... 50 ° C, which generally leads to an increase in fuel efficiency. KEY WORDS: ENGINE WITH CARBURETTOR POWER SUPPLY SYSTEM, ALCOHOL-CONTAINING GASOLINE, HEATED AIR AT THE INLET, LOW OPERATING TEMPERATURE, INCREASING ENGINE ENERGY EFFICIENCY.

Mapping K factor variations and its causes in a modern, spark-ignition engine

The Research Octane Number (RON) and the Motor Octane Number (MON) are primary fuel properties that characterize gasoline’s knock resistance in spark ignition engines. The utility of these two metrics, however, has been questioned with advancements in engine technologies that significantly change the thermochemical environment inside the cylinder. The Octane Index, OI = (1-K)·RON + K·MON, has therefore been proposed to characterize the knock resistance in modern engines where K weights the relative contribution of the RON and MON and is primarily determined by engine design and operating conditions. Quantifying the K factor is central to understanding a fuel’s anti-knock performance in a modern spark-ignition (SI) engine.This work therefore determines the map of K over engine operating conditions for a 2-litre, 4-cylinder turbocharged, gasoline direct-injection engine. To achieve this, a novel blending system for primary reference fuels (PRFs) was developed to determine K by matching the knock resistance of a 91.6-RON certification gasoline with a PRF at each operating condition. The K values are determined over the engine map with normal and high intake air and coolant temperatures. At normal operating temperature, K is negative at most knock-limited conditions, consistent with previous findings, whereas at high operating temperatures, K is mostly positive and, indeed, exceeds 1 near 8 bar BMEP and 3000 RPM, demonstrating the relevance of the MON at some conditions of practical significance. Further analysis is conducted via engine simulations to examine the relationship between K and end gas conditions, and a strong correlation is observed between K and the unburned gas temperature at the later stages of combustion. This correlation is argued to have a sound physical basis in the engine’s thermochemistry, supporting the utility of this K factor method.