SI Engine Research Articles

On the possibility to simulate the operation of a SI engine using alternative gaseous fuels

A thermodynamic combustion model developed in AVL BOOST software was used in order to evaluate the pollutant emissions, performance and efficiency parameters of a spark ignition engine Renault K7M-710 fueled with compressed natural gas, hydrogen and blends of compressed natural gas and hydrogen (hythane). Multiple research studies have concluded that for the near future hythane could be the most promising alternative fuel because it has the advantages of both its components. In our previous work the model was validated for the performance and efficiency parameters by comparison of simulation results with experimental data acquired when the engine was fueled with gasoline. In this work the model was improved and can predict the values of pollutant emissions when the engine is running with the studied alternative fuels. As the percentage of hydrogen in hythane is increased, the power of the engine rises, the brake specific fuel consumption, carbon dioxide, carbon monoxide and total unburned hydrocarbon emissions decrease while nitrogen oxides increase. The values of peak fire pressure, maximum pressure derivative and peak fire temperature in cycle are higher, leading to an increased probability of knock occurrence. To avoid this phenomenon an optimum correlation between the natural gas-hydrogen blend, the air-fuel ratio, the spark advance and the engine operating condition needs to be found.

Performance and Emission evaluation of Butanol blends in SI Engine

In recent times, butanol emerges as one of the most promising option to diminish the prolong use of fossil products. The testing of different blends and composition of butanol with gasoline is newest theme of research. In the present work, three different fuels are prepared by using 5%, 10% and 15% blends of butanol with gasoline. The important performance parameters & emission characteristics of a conventional SI engine namely, brake power, torque, brake specific fuel consumption, fuel power, brake specific energy consumption, brake mean effective pressure, un-burnt HC emissions, CO emissions, NOx emissions, and CO2 emissions are tested. Result shows that the butanol blend of 15% is the most appropriate to use as fuel. The experimentally measured values of butanol blends in gasoline confirms that the properties of butanol are quite adaptive with gasoline which implies that no engine modifications required for using butanol blends with gasoline as a replacement to gasoline.

Turbulent charge burning in SI engines

The article describes turbulent combustion in the front of a spherical flame of the fuel-air mixture in a spark-ignition engine. The paper considers two mathematical models of the workflow : a well-known “entrainment or eddy burning model” and a “laminar model of turbulent combustion” in the authors’ version of this paper. Both models are based on the Damköhler hypothesis (Damköhler G., 1940) on the turbulent combustion of gas, but have a significant difference in the mathematical formulation. Although both models contain empirical parameters, the authors’ model is much simpler and clearer. In numerical simulation, both mathematical models produce similar results. The authors also propose a “combined mathematical model of frontal turbulent combustion”.

Use of CNG and Hi-octane gasoline in SI engine: a comparative study of performance, emission, and lubrication oil deterioration

ABSTRACT The search for alternative fuels (i.e. other than gasoline) is a continuous area of research. In the present work, a comparative study has been conducted by employing a liquid ((G)97 ) and a gaseous (CNG) fuel in a spark ignition engine. Engine performance, emission. and lubrication oil condition tests have been performed for two fuels by varying operating conditions according to comprehensive sampling plans in each area. Speed was incrementally increased in two phases over the investigated range of rpm for brake power and peak torque. For specific fuel consumption and emission tests, speed was increased through a uniform increment rises over the investigated range of rpm. Lubrication oil samples have been collected over 120 h of engine running with topping for drain out quantity and tests were performed as per ASTM standards. (G)97 showed an improved performance, i.e. 28.8% increase in case of brake power as compared to CNG; however, CNG outperformed (G)97 in case of emission contents and brake-specific fuel consumption (17.2% decrease). Moreover, emission data were fitted to Weibull distribution to ascertain the adequacy for a 95% confidence interval. Furthermore, wear debris (Iron (Fe), aluminum (Al), copper (Cu), chromium (Cr)), lubrication oil condition (kinematic viscosity, flash point and total base number (TBN), and additives depletion (zinc (Zn), calcium (Ca)) showed a visible improvement in case of CNG as compared to (G)97 . Lubrication oil analyses depicted 4.9%, 9.5%, and 3.2% reduction in viscosity, flash point, and TBN for (G) 97 , respectively. However, Fe, Al, and Cu decreased by 12.9%, 29.1%, and 37.7% for CNG, respectively. Mechanisms involved in combustion and lubrication oil deterioration have also been discussed for two fuels.

Experimental study on an SI engine fueled by gasoline, ethanol and acetylene at partial loads

Oil is one of the main energy sources used in internal combustion engines. The high level of environmental pollution, continuous limitation of emission rates, increasing environmental awareness, and uncertainty in oil prices, have been driving the energy world to alternative fuels for the last decades. In this study, ethanol and acetylene have been suggested as alternative fuels to gasoline since they can be produced from non-petroleum resources and the effects of gasoline, ethanol and acetylene on the emission parameters and engine performance of a spark-ignition engine were investigated. The experiments have been carried out under 25% and 50% constant loads at 1500 rpm and different excess air ratios. The engine used in the experiment is a four-cylinder, four-stroke and water-cooled internal combustion engine. When using ethanol and acetylene, UHC and NO emissions significantly reduced compared to gasoline. As a result of the experiments, it was observed that acetylene have better thermal efficiency and emission values than that of gasoline and ethanol in high EAR values.

Studi eksperimental pengaturan waktu pengapian pada mesin 4 langkah 1 silinder berbahan bakar E25

The use of ethanol as a mixture of premium is for reducing dependency to the primuim, considering that premium is not renewable. The goal of the ethanol addition in a fuel is to increase the octane number. However the heating value of the ethanol is lower then premium, so it will decrease the performance of the SI engine. The study aimed for increasing the performance of SI engine using E25 as mixture of premium-ethanol. The performance of engine was measured by engine test bed on chassis. Change load method is used in the experiment. The experiments result is advancing the time of ignition at 4 degree that can improve the engine performance. The result of changes load use E25 fuel with advanced time of ignition at 4 degree can increase engine performance as torque, power, bmep, efficiency thermal and bsfc were decrease.

Understanding the correlation between auto-ignition, heat release and knocking characteristics through optical engines with high compression ratio

Improving compression ratio is an effective way to meet higher thermal efficiency and lower CO2 emissions for internal combustion engines. However, the severe thermodynamic condition under low speed and high road may promote the possibility of auto-ignition and damage engine body if it is uncontrollable. Therefore, further study on the correlation between auto-ignition and knocking characteristics are necessary for modern engines with high compression ratio. In this study, combined with high-speed direct photography and simultaneous pressure acquisition, flame images and in-cylinder pressures characterizing auto-ignition, heat release rate and knocking combustion were studied based on optical engine experiments. The results show that auto-ignition occurs in all engine cycles under current critical knocking conditions, and fast SI flame speed cycles is more likely to facilitate end-gas auto-ignition. However, the auto-ignition flame speed is comparable to the SI flame and auto-ignition is not a sufficient condition for knock: for some cycles multipoint auto-ignitions occur near the SI flame front and result in two peak heat release rate, which is beneficial to engine thermal efficiency. Further analysis shows that there is no obvious pertinence between knock intensity and auto-ignition onset while knock intensity strongly depends on the peak HRR per unit volume. High peak HRR per unit volume always results in knocking combustion. The current study shall give insights into utilizing auto-ignition in high compression ratio SI engines.

Quantitative investigation the influences of the injection timing under single and double injection strategies on performance, combustion and emissions characteristics of a GDI SI engine fueled with gasoline/ethanol blend

An experimental investigation of the single injection strategy and double injection strategy on the combustion phasing, performance and emissions characteristics in the GDI engine fueled with E10 was conducted. The effective expansion ratio (EER), effective expansion efficiency (EEE) and residual gas fraction (RGF) characteristics were further investigated under single injection strategy and double injection strategy. The result indicated that under the single injection strategy, the change trends of the EER and EEE were the same as the gasoline effective brake thermal efficiency (GEBTE). The maximum value of the EER and EEE were 7.86 and 0.513, and the maximum decrease magnitude of EER and EEE was 8.86% and 3.63%, respectively. However, the change trend of RGF was opposite to BTE, and its maximum increase magnitude of RGF was 4.72%. In addition, with the increase of the second end of injection timing, the peak combustion pressure (PCP), maximum heat release rate (HRR) and mean in-cylinder temperature gradually increased. The position of the maximum PCP and maximum HRR closed to the TDC. The CA50 combustion location advanced and the combustion duration shortened, and thereby increasing the EER, EEE and GEBTE. Finally, comparing the single injection strategy with the double injection strategy, the GEBTE decreased by 5.09%, while the NOx and HC emissions sharply decreased by 54.46%, 31.81%, respectively.

Numerical Analysis of End-Gas Autoignition and Pressure Oscillation in a Downsized SI Engine Using Large Eddy Simulation

Knock and super-knock are abnormal combustion phenomena in engines, however, they are hard to study comprehensively through optical experimental methods due to their inherent destructive nature. In present work, the methodology of large eddy simulation (LES) coupled with G equations and a detailed mechanism of primary reference fuel (PRF) combustion is utilized to address the mechanisms of knock and super-knock phenomena in a downsized spark ignition gasoline engine. The knock and super-knock with pressure oscillation are qualitatively duplicated through present numerical models. As a result, the combustion and onset of autoignition is more likely to occur at top dead center (TDC), which causes end gas at a higher temperature and pressure. It is reasonable to conclude that the intensity of knock is not only proportional to the mass fraction of mixtures burned by the autoignition flame but the thermodynamics of the unburned end-gas mixture, and the effect of thermodynamics is more important. It also turns out that two auto-ignitions occur in conventional knock conditions, while only one auto-ignition takes place in super-knock conditions. However, the single autoignition couples with the pressure wave and they reinforce each other, which eventually evolves into detonation combustion. This work gives the valuable insights into knock phenomena in spark ignition gasoline engines.

Transportation fuel from plastic wastes: Production, purification and SI engine tests

Thermal pyrolysis of HDPE, LDPE, PP, PS, PET and PUR plastic wastes were performed in a batch reactor equipped with a temperature controlled reflux and the yields of pyrolysis oils and liquid fuels suitable for transportation were determined. The gasoline fractions were investigated by GC-MS and tested in a traditional spark-ignition engine without any modifications or fuel blending. Fuel consumption and exhaust gas emission (NOx, CO) were measured and compared to a commercial fuel (gasoline, RON = 95). PS generated 70.5% gasoline range hydrocarbons from the solid waste, followed by PP with 42.1%, LDPE with 40.8% and HDPE with 37.3%. Liquid product was not observed during PET pyrolysis. The engine was easily running with neat gasoline fractions obtained from HDPE, LDPE, PP and PS distillation; however, it was not able to start the engine with the neat dehydrated PUR distillate. The volumetric fuel consumption was reduced by 9.1–9.4% in case of PS compared to commercial gasoline (RON = 95) but the NOx emission was increased by 82–147%. Fuel consumption reduction was noticeable at HDPE, LDPE and PP as well. PS gasoline decreased by 91–96%, while HDPE, LDPE and PP more likely increased the CO emission of the engine compared to commercial gasoline.

Investigation of the effects of lean mixtures on combustion and particulate emissions in a DISI engine fueled with bioethanol-gasoline blends

Ethanol, an oxygen-containing biofuel, is a promising alternative fuel for SI engines. Ethanol/gasoline blends with <10% volume ratio are available approaches to minimize life-cycle greenhouse gas emissions, ethanol addition as high as 21% vol. is potentially used duce to anti-knock performance, improvement to thermal efficiency and greenhouse gas emissions. The ethanol/gasoline blend E20 was investigated in this study in terms of particle emissions reduction and engine efficiency. The combustion, particle number (PN) concentration, and particle size distribution of a turbo-charged GDI engine fueled with E20 were investigated under both stoichiometric and lean burn conditions. The particle size distribution was measured in excess air ratio and injection timing. The results show that the combustion efficiency of E20 fuel increased under lean burn conditions – up to an excess air coefficient of 1.2 – 1.3 – and the fuel consumption rate was 5% lower than the gasoline consumption rate under stoichiometric conditions. The PN emissions of nucleation and accumulation particles during lean burn were also markedly reduced. The lowest PN emissions were observed in the leanest mixture (excess air ratio 1.3), and the averaged size of particles decreased as the lean mixture increased resulting in a significant reduction in particle surface area concentration. The PN emissions decreased with retarded injection timing in the early intake stroke as accumulation particles decreased significantly. The total particle quantity increased as the fuel was injected in the late intake stroke and PN (>20 nm) quantity increased as the injection timing was retarded to 240°CA BTDC.

Energy Efficiency Ratio (EER) of Novel Air Conditioning System on LPG Fuelled Vehicle: A Lab-Scale Investigation

Alternative fuels have become an effective solution to reduce the impact of road transport on the environment. On the other hand, the growing uses of air-conditioning (AC) have contributed to worsening the fuel economy of passenger vehicles. Liquid petroleum gas (LPG), if injected in the gaseous phase to power SI engines, may allow reducing the fuel consumption due to AC devices through the recovery of cooling energy from the fuel systems. This paper presents lab-scale tests of an air conditioning system prototype for LPG-fuelled vehicles. The prototype has been assembled using standard vehicle components to quantify the cooling energy recoverable from the LPG evaporation before the fuel is injected into the engine intake manifold. Temperature and humidity of the air exiting the LPG evaporator are measured for fuel mass flow rates typical of light-duty vehicles. The energy efficiency ratio (EER) of the prototype achieves 2.72 when cooling power equals 1.2 kW. Although the system tested needs improvements, the experimental data show that the cooling energy recovered by LPG evaporation can significantly reduce the power consumption of standard AC systems in passenger cars.

EMISSIONS AND PERFORMANCE CHARACTERISTICS OF AN SI ENGINE WITH BIOGAS FUEL AT DIFFERENT CO2 RATIOS

Nowadays increasing emission regulations and environmental concerns have led to the use of alternative fuels in internal combustion engines. Biogas is an alternative fuel that can be produced with clean, green and natural resources. In this study, a single cylinder, four stroke SI engine was operated at stoichiometric conditions, 2800 rpm constant engine speed with biogas fuel at different ratios. As biogas fuel, methane (CH4) and CO2 were used during engine tests. Test results which were taken by using only gasoline were compared with the results obtained by using biogas fuel at different CO2 ratios (10%, 20%, 30% and 40% by volume). Although it was determined specific CO emissions decrease and THC emissions slightly increases with the increasing CO2 ratio, it is foreseen that the increase in THC emissions can be prevented by the use of three way catalytic converter. Although the NOx emissions increase with the use of biogas compared to gasoline, it was significantly reduced by the increased CO2 rate in the biogas fuel, the CO2's heat carrying capacity and reducing the O2 availability of the fuel. On the other hand, because of the high cost of purification process of biogas and after-treatment equipment, it is foreseen that use of biogas at high ratio of CO2 in SI engines will be advantageous in terms of NOx emissions.

Comparison of Regulated and Unregulated Emissions and Fuel Economy of SI Engines with Three Fuels: RON95, M15, and E10

Comparison of Regulated and Unregulated Emissions and Fuel Economy of SI Engines with Three Fuels: RON95, M15, and E10

The effect of SiO2 nanoparticles content in engine oil on tribological properties of valvetrain chain transmission components

The drive from the crankshaft to the camshaft in an internal combustion engine is usually carried out by means of a cogged belt transmission or a chain transmission when high millage is required without service operations. The valvetrains in CI engines sometimes use the gear transmissions, and the historical rather bevel gear can be found in old cars of collectors or in some motorcycle engines. The chain gear used in SI engines has a two- or three-row chain with high strength, due the unevenness of loads that additionally induce chain pulling and valve timing deregulation. The chain transmission requires the use of pre-tensioners, usually self-acting and driven by springs or oil pressure. The vibrations and chain runout are limited using plastic guides placed on the outside of the long straight sections of the chain. The model of the chain transmission developed with the use of the Finite Elements Method, which operates under oil lubrication conditions, was analyzed. Such the model allowed obtaining weight and mass inertial moments of components. The aim of the study was to evaluate the effect of SiO2 nanoparticles content in engine oil on the friction between chain transmission components. The resulted values of the friction torque in the chain transmission operating in different conditions of lubrication have been presented in the paper.

Quantitative evaluation of n-butane concentration on knock severity of a natural gas heavy-duty SI engine

Knocking combustion of a natural gas spark ignition engine with the addition of n-butane was investigated. Specially, the effects of n-butane concentration on knock severity were quantitatively evaluated with engine full-load at various engine speeds. The results show that with an increase in n-butane concentration, the peaks of in-cylinder pressure and heat release rate increase, combustion duration is shortened, and CA50 is advanced. At high speeds, n-butane concentration has a more pronounced influence on combustion and knock. With increased n-butane concentration, cyclic pressure traces oscillate more and more violently, the maximum pressure rise rate (MPRR) and the maximum amplitude of pressure oscillation (MAPO) in some cycles increase significantly. Here the MPRR threshold of light knock cycle is defined at 1.0 MPa/CAD, and the one of heavy knock cycle is 4.0 MPa/CAD. Meanwhile the MAPO threshold of light knock cycle is set at 0.1 MPa, and the one of heavy knock cycle is 0.3 MPa. Based on these thresholds and the probability of knock severity, light and heavy knock conditions are identified. Moreover, the combustion close to light knock may increase thermal efficiency, and heavy knock has caused the erosion of aluminum piston crown and top land in the experiment.

Water Methanol Injection based Four Stroke Single Cylinder SI Engine Using an Electronic Control Unit

Now a days there is an Increasing rate of pollution which cause the environmental as well as human hazards. Pollutions are mostly caused from two main areas one is from industrial areas and another one is automobiles. In recent technologies, researchers have found various alternative methods to reduce emission, we taken an initiative to introduce water with alcohol in precise measure to increase performance and reduction of emission in all standards of automobile. Reduction of exhaust emission is attained by adding a secondary fuel along with the SI engine primary fuel. Water and methanol mixture is a secondary fuel injected into the combustion chamber with the support of an injector. An inlet manifold is modified to fix the injector and the flow of H2O (water) and CH3OH (methanol) mixture and injection timing is controlled by electronic control unit (ECU). By the experimental investigation of this project, we had studied that the emission from the engine is reduced, the fuel consumption of the vehicle is decreases, and it has improve the inter-cooling capacity of engine and efficiency of the engine improved.

Effects of CNG Injection Pressure on Performance, Emission and Combustion Characteristics of Multi-cylinder SI Engine

This Paper shows the effect of port fuel injection pressure of CNG in 3-cylinder SI Engine at Wide Open Throttle position using sequential port fuel injection system. All trials are performed on 4-stroke, 796 cc MPFI S.I engine at injection pressure of 2.0, 2.2, 2.4, 2.6, 2.8 bar for constant speed of 2500, 3000, 3500, 4000 &amp; 4500 rpm. During the trial compression ratio is kept constant at 9.2 with Maximum Brake Torque (MBT) spark timing of 15oBTDC. Optimum torque is obtained for CNG at injection pressure of 2.6 bar and 3000 rpm. Gasoline trials are performed at same compression ratio for comparison with CNG at same injection pressure. Performance and emission characteristics with combustion analysis are performed at optimum injection pressure of 2.6 bar.

Effects of SI Engine Operating Temperature Fuelled with Gasoline Ethanol Blends on Performance and Emissions Characteristics

Effects of SI Engine Operating Temperature Fuelled with Gasoline Ethanol Blends on Performance and Emissions Characteristics

Numerical Study of Combustion Characteristics, Performance and Emissions of an SI Engine Running on Gasoline, Ethanol and LPG

Numerical Study of Combustion Characteristics, Performance and Emissions of an SI Engine Running on Gasoline, Ethanol and LPG