SI Engine Research Articles

Experimental study of gasoline-ethanol-hydrogen blends combustion in an SI engine

This study presents experimental results of engine performance, combustion and emissions in an SI engine fueled by gasoline-ethanol-hydrogen blends. In the experimental studies, engine performance and emission values were analyzed fueled by gasoline, gasoline-ethanol and gasoline-ethanol-hydrogen blends, respectively. When ethanol has been added volumetrically to gasoline 20% of ethanol (G80E20), engine performance and emissions have been worsened. However, the engine performance and emission values have been improved with the adding of hydrogen to blend. The results showed that the addition of hydrogen to the gasoline-ethanol blend improved the combustion process and improved the combustion efficiency, expanded the combustibility range of the gasoline-ethanol blend, reduced emissions. But, nitrogen oxide emission values increased with the adding of hydrogen.

Evaluation of the flame propagation within an SI engine using flame imaging and LES

This work shows experiments and simulations of the fired operation of a spark ignition engine with port-fuelled injection. The test rig considered is an optically accessible single cylinder engine specifically designed at TU Darmstadt for the detailed investigation of in-cylinder processes and model validation. The engine was operated under lean conditions using iso-octane as a substitute for gasoline. Experiments have been conducted to provide a sound database of the combustion process. A planar flame imaging technique has been applied within the swirl- and tumble-planes to provide statistical information on the combustion process to complement a pressure-based comparison between simulation and experiments. This data is then analysed and used to assess the large eddy simulation performed within this work. For the simulation, the engine code KIVA has been extended by the dynamically thickened flame model combined with chemistry reduction by means of pressure dependent tabulation. Sixty cycles have been simulated to perform a statistical evaluation. Based on a detailed comparison with the experimental data, a systematic study has been conducted to obtain insight into the most crucial modelling uncertainties.

Experimental Investigation of Combustion Characteristics of Homogenous Charge Compression Ignition Engine

In diesel compression ignition engine, simultaneous reduction of NOx and PM is extremely challenging task. The most favorable solution for this is HCCI. It is an impulsive auto ignition of very lean air fuel mixture at multiple sites. It has advantages of both CI and SI engines. It also gives higher thermal efficiency like CI engines, higher ROHR, minimum DOC and has no flame propagation and mainly it has simultaneous control over NOx as well as PM. The combustion of homogeneous mixture in HCCI combustion helps in reducing DOC because of higher ROHR. The present experiment is conducted on engine having two cylinders; they are made to operate on HCCI and conventional CI mode respectively. Both DI and PI systems were used simultaneously to investigate the performance characteristics. The toughest part is to prepare homogeneous mixture for combustion. As the diesel is a low volatile fuel, the preparation of homogeneous mixture is difficult therefore diesel vaporizer comes into picture. EGR is used to control the ROHR. To investigate the combustion characteristics experiment was performed at different relative air fuel ratios (λ). The DOC and ROHR is increases with increasing λ. EGR dilutes the homogeneous mixture and leads to minimum NOx emission by keeping maximum temperature in cylinder low. The increased boost pressure is responsible for short DOC and high rate of combustion. Also the indicated mean effective pressure is improved by 3% by DI method as compared to PI in HCCI.

EXHAUST EMISSIONS OF 4 STROKE SPARK IGNITION ENGINE WITH INDIRECT INJECTION SYSTEM USING GASOLINE-ETHANOL FUEL

Gasohol can be replaced in the spark ignition engine (SI engine) as gasoline substitution having lower emissions exhaust gas, making it more environmentally friendly. The aim of study was to investigate the effect of gasoline- ethanol ratio on the gas exhaust emission of SI engine injection system. In this study, it was used the 4-stroke gasoline engine injection system by using the injector as a fuel input device. The engine had a 124.8 cc single-cylinder engine with compression ratio of 9.3:1. The variations of gasohol were gasohol E0, E10, E20, E30, E40, E50, E60, E70, E80, E90 and E100 with range of speeds; 1500 rpm, 2000 rpm, 2500 rpm, 3000 rpm, 3500 rpm, 4000 rpm, 4500 rpm and 5000 rpm. The research was run by rearranging the standard ECU to obtain the AFR stoichiometric of each gasohol mixture. The exhaust emissions were measured by using the Stargas-898. The results show that the addition of ethanol content was able to increase the CO 2 emissions , however, it would decrease the CO and HC levels. Compare to the gasoline fuel, gasohol has a lower emission of CO, HC and higher of CO 2 and O 2 emissions.

Quasi dimensional numerical investigation of syngas fuelled engine operation: MBT operation and parametric sensitivity analysis

The formulation, validation and application of a thermodynamic quasi dimensional SI engine simulation model for syngas fuelled operation is reported. The QD approach establishes the dependence of turbulent combustion on mixture thermo-physical properties and fluid domain average turbulent parameters, eliminating the need for domain discretization (unlike in multi-dimensional models). Turbulent combustion is formulated along the Eddy Entrainment Laminar Burn-up concept (Williams-Klimov criterion) with non-linear dependence of mixture burn rate on local laminar flame speed and turbulent intensity. Simulations are reported for syngas fuelled operation of a six cylinder engine and compared with experimental pressure and heat release traces. Maximum brake torque stoichiometric operation pressure and heat release simulation traces evolve closely with corresponding experimental traces. The simulation peak pressure and IMEP deviations remain within 5% and 2% of experimental traces respectively while the position of peak pressure overlaps within ±0.5deg. Parametric sensitivity analysis for load, mixture quality and ignition timing are also addressed. Overall, the simulation results are in accordance within 5% of experimental results as long as the parametric variations are within the regimes of tuning of empirical correlations. In general, the versatility and robustness of quasi dimensional approach to simulate non-regular bio-derived alternative fuels is established.

Potentially CO2-neutral Fuels for Clean SI Engines

Potentially CO2-neutral Fuels for Clean SI Engines

Performance and combustion characteristics of an SI engine fueled with fusel oil-gasoline at different water content

The main objective of the current study is to investigate the impacts of fusel oil-gasoline blends with different water content on performance and combustion characteristics of an SI engine. The water content of fusel oil is reduced by employing rotary extractor method. The parameters examined in the current study are the effects of test fuels upon engine performance criteria, fuel combustion, location of CA50 and coefficient of variation of indicated mean effective pressure (COVIMEP). The experiments are conducted in a SI engine with two blending ratio of gasoline-fusel oil (FBWE10 and FAWE10) in addition to pure gasoline as a standard fuel under different engine speeds and constant 45% of WOT engine load. The study results reveal that engine power, torque, and brake thermal efficiency have slightly improved with fusel oil-gasoline blends that were obvious clearly after reduction of water content. On the other hand, though the brake specific fuel consumption of FAWE10 slightly improve compared to FBWE10 but still higher than gasoline. Furthermore, the peak in-cylinder pressure, rate of heat release, and rate of pressure rise enhanced with fusel oil-gasoline blends. The (CA 0–10) and (CA 10–90) duration could be simultaneously decreased by reducing the water content of fusel oil, all of that are helpful to improve the stability of combustion and thought to be reasons for the reduction in COVIMEP. As a conclusion, the reduction of fusel oil water content has played positively to enhance the combustion and performance characteristics of the fuel blend and result in more stable engine operation.

Knock probability estimation through an in-cylinder temperature model with exogenous noise

Abstract This paper presents a new knock model which combines a deterministic knock model based on the in-cylinder temperature and an exogenous noise disturbing this temperature. The autoignition of the end-gas is modelled by an Arrhenius-like function and the knock probability is estimated by propagating a virtual error probability distribution. Results show that the random nature of knock can be explained by uncertainties at the in-cylinder temperature estimation. The model only has one parameter for calibration and thus can be easily adapted online. In order to reduce the measurement uncertainties associated with the air mass flow sensor, the trapped mass is derived from the in-cylinder pressure resonance, which improves the knock probability estimation and reduces the number of sensors needed for the model. A four stroke SI engine was used for model validation. By varying the intake temperature, the engine speed, the injected fuel mass, and the spark advance, specific tests were conducted, which furnished data with various knock intensities and probabilities. The new model is able to predict the knock probability within a sufficient range at various operating conditions. The trapped mass obtained by the acoustical model was compared in steady conditions by using a fuel balance and a lambda sensor and differences below 1 % were found.

Analysis of thermodynamic scope engine simulation model empirical coefficients: Suitability assessment and tuning of conventional hydrocarbon fuel coefficients for bio syngas

The sensitivity of empirical correlations and coefficients of thermodynamic quasi and zero dimensional SI engine models to mixture thermo-chemistry and engine thermo-kinematic response variations is addressed. Mixture thermo-chemistry alterations, as in case engine operation with non-regular alternatives, and accompanying in-cylinder fluid flow and combustion dynamics perturbations induce variations in full cycle thermodynamic and process thermo-kinematic response with potential influence on empirical coefficients. As an example, producer gas and natural gas thermo-physical properties differ significantly, extending to thermo-kinematic response over a range of operating conditions. Literature indicates monotonous adoptions of conventional fuel coefficients for simulation studies with non-regular fuels and tuning efforts are directed at initial and boundary conditions, which are many times thermodynamically untenable. The current work evaluates the suitability of empirical correlations and coefficients tuned for conventional hydrocarbon fuels, for numerical simulation of producer gas fuelled operation. Producer gas specific coefficients are evolved, following a generic approach, wherever necessary.Assessment of producer gas thermo-physical properties indicates four times higher thermal conductivity of producer gas (40.0 mW/mK) compared to gasoline (11.2 mW/mK), attributed to the presence of hydrogen. The influence is on convective cooling which is reflected in about 32% cooling load as against 25% for spark ignited engines. In response, the Reynolds number power coefficient of convective heat transfer correlation nearly doubles from 0.35 to 0.76. Analysing laminar flame speed coefficients, the inability of CHEMKIN-III to accurately predict laminar flame speed of hydrogen containing gases requiring adoption of CHEMKIN-II is a key observation. Substantial deviations are also observed for apparent heat release profiles with extended terminal stage combustion duration for producer gas, attributed to enhanced convective cooling. Curve fit analysis evolves producer gas specific shape and efficiency coefficients of 0.71 and 2.23 as against 2.0 and 5.0 for conventional fuels. The terminal combustion duration also changes from 1.22 to 2.12 ms. Using tuned coefficients permits near concurrent evolution of simulation and experimental pressure and heat release profiles establishing the need for fuel specific coefficients.

Effect of compression ratio and hydrogen addition on part throttle performance of a LPG fuelled lean burn spark ignition engine

A single cylinder CI engine was modified to operate as a LPG fuelled lean burn SI engine. The engine was tested at 1500rpm and 20% throttle opening at compression ratios 9:1, 10:1, 10.5:1 and 11:1 by varying equivalence ratios. The influence of compression ratio and 15% hydrogen substitution on energy basis at the optimal compression ratio of 10.5:1 on performance, emission and combustion behavior were studied and compared. The brake thermal efficiency and brake power output increases with rise in compression ratio, and above a critical value of 10.5:1 the improvement was small when compared to the increase in emissions. The advantage of brake thermal efficiency from higher compression ratio is narrow under low load conditions. The ever increasing load due to the auxiliaries which are likely to grow more require better low load performance and emissions. Wide flammable limits of hydrogen enable ultra-lean combustion and its anti-knock enhancement makes it advantageous compared to increasing the compression ratio at part throttle condition. Hydrogen addition enhanced the combustion rate and heat release rate, reduced cyclic variations, and extended the lean limit of operation. There was perceptible improvement in brake thermal efficiency, brake power and considerable reductions in hydrocarbon, carbon monoxide and carbon dioxide levels. Due to retarded ignition timing the NOx emission increase was not significant.

Performance and Emission Analysis of Diesel Engine by Copper Coating Over Piston Crown and Cylinder Head

The major toxins emitted from SI engine are carbon monoxide (CO) and unburnt hydrocarbons (UHC). These are harmful and create health problems to human beings, and hence control of these pollutants calls for instant attention. It has been recognized from the literature review that copper coating inside the cylinder head and over the piston crown will reduce the emission and increase the overall performance. Hence, in this Project work piston crown and engine head are coated using copper and experiment are conducted. A Kirloskar AV1 engine is used for conducting experiment. The copper coated piston crown and engine head is used to reduce the emission (HC, CO, O2, and CO2). The performance and characteristics of the copper coated engine has been studied.

Analysis of air flow velocity distribution in the intake system of an SI engine

The conditions of air flow in the intake determine power generated by the engine to a large extent. The biggest resistances in flow of the air sucked or pumped into the engine are generated by the throttle, which is at the same time the main component which allows for regulation of engine power. For the purpose of research conducted in this work, time density of engine work points in analyzed velocity profiles was determined with the use of Engine Road Load Simulator. Thanks to the knowledge of time velocity, it was possible to determine throttle positions at which the engine operates most frequently. With the use of image analysis methods, obtained parameters were experimentally researched, considering flow disturbances which are the effect of air flow through the throttle and uneven air distribution in the intake manifold of a four-cylinder engine.

Evaluation of usefulness of mass flow meter to the survey of SI engine cylinder filling in one working cycle

The article presents the technique of the usage of mass flow meter to the fill survey of a cylinder in the multicylinder engine, in each working cycles. The result of correctness of the survey was grounded on the comparison of air masses: the one registered with the usage of the flow meter and the other one calculated on the basis of mixture parameters. The flow meter was located in the consolidated part of suction system in front of the throttle valve. Mixture parameters were determined on the basis of time of fuel injection and measured lzm factor of burnt mixture. The studies were carried out in the whole operating range of engine. Discrepancies between the measured and calculated values for 93% of all of the cycles fall within the ambit of ±3% of the actual value.

The effect of hydrogen on the performance and emissions of an SI engine having a high compression ratio fuelled by compressed natural gas

The aim of this paper is investigation of the effect of hydrogen on engine performance and emissions characteristics of an SI engine, having a high compression ratio, fuelled by HCNG (hydrogen enriched compressed natural gas) blend. The experiments were carried out at 1500, 2000 and 2500 rpm under full load conditions of a modified Isuzu 3.9 L engine, having a compression ratio of 12.5. The engine brake power, brake thermal efficiency, combustion analysis and emissions parameters were realized at 5, 10 15 and 20 deg. CA BTDC (crank angle before top dead center) ignition timings and in excess air ratios of 0.9–1.3 fuelled by hydrogen enriched compressed natural gas (100/0, 95/5, 90/10 and 80/20 of % natural gas/hydrogen).The experimental results showed that the maximum power values were generally obtained with HCNG5 (5% hydrogen in natural gas) fuel. The optimum ignition timing that was obtained according to the maximum brake torque was retarded by the addition of hydrogen to CNG (compressed natural gas), while it was advanced by increasing the engine speed. Furthermore, it was observed that the BTE (brake thermal efficiency) generally declined with the hydrogen addition to compressed natural gas and increasing the engine speed. Additionally, the curves of cylinder pressure and ROHR (rate of heat release values) generally closed to top dead center with the increasing of the hydrogen fraction in the blend and a decreasing engine speed. The hydrocarbon and carbon monoxide emissions generally obtained were lower than the Euro-5 and Euro-6 standards.

Advancement and Experimental Analysis of SI Engine by using Electrolysis Process (H2O)

Advancement and Experimental Analysis of SI Engine by using Electrolysis Process (H2O)

Energy and Exergy Analysis on Si Engine by Blend of Ethanol with Petrol

Need to use renewable energy in the form of ethanol fuel derived using agriculture waste to reduce load on petrol derived from crude oil, which is available in limited quantity. This is mostly due to stock of petroleum product are depleting day by day, hence more use of renewable fuels gets attraction in developing country like India. In recent years, Considerable efforts made to develop and introduce alternative renewable fuel, to replace conventional petroleum-base fuels.The main objective of the current work id to investigate influences of blends of ethanol-petrol blend used in IC engine performance using energy and exergy analysis. Here, experimental work divided into mainly two parts. In first part, Engine performance carried out using E0, E25, E40 and E100 blends of ethanol-petrol blends. In other part, exergy analysis carried out. Experimental test set-up developed in laboratory. The stationary petrol engine was run in laboratory at a medium speed, variable load condition experienced in most urban driving conditions and various measurements like fuel flow, exhaust temperature, exhaust emission measurement and exhaust smoke test were carried out. The fuel properties of biodiesel such as kinematic viscosity, calorific value, flash point, carbon residue and specific gravity investigated. Heat balance sheet and availability calculated for different condition like E0, E25, E40 and E100 blends of ethanol-petrol blends.

Parametric study on some combustion characteristics in a natural gas fueled dual plug SI engine

A parametric study on some combustion characteristics was carried out in a natural gas fueled dual plugs SI engine. Mass fraction burned, cylinder pressure histories and combustion durations of the engine were investigated by three equivalence ratio and spark advance for three spark plug configurations. It was found that equivalence ratio and spark plug configurations were more effective parameters on the total combustion duration than spark timing and was concluded that centrally located single plug configuration for equivalence ratio of 1.0 gives best combustion characteristics in compared to the other conditions. In addition, presented study showed that dual plugs serve an alternative for fast combustion in case of geometric constraints to use central location of the plug.

Model-based analysis of sensor faults in SI engine

Model-based analysis of sensor faults in SI engine

Model-based analysis of sensor faults in SI engine

The article focuses on the fault not diagnosed by the OBD system. Apart from mechanical damages sensor faults are a serious group. Although the sensor values are constantly monitored, some errors are not detected. The article presents a diagnostic model of the air intake system of SI engine, which generates the control and work parameters of the engine for fault-free state. The parameters obtained from the reference model can be compared with the parameters measured for the engine in any operating condition. Based on the model the impact of sensor faults for other parameters was analyzed. Some errors can be masked by the adaptive control system of the engine, which changes the parameters of the engine control. Simulation tests were verified on the test bench.

Intake System Effects on In-Cylinder Flow Field in a Four-Valve SI Engine

Intake System Effects on In-Cylinder Flow Field in a Four-Valve SI Engine