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The purpose of this work was to obtain a detailed comparison of engine performance and exhaust emissions from compressed natural gas and gasoline fueled Spark Ignition (SI) engines. This research deals with a quasi-dimensional, two-zone, thermodynamic simulation of four-stroke SI engine fueled with a wide range of liquid and gaseous fuels. The results show that the power output of the engine was reduced when fueled by natural gas due to its low volumetric efficiency, but both fuels exhibited nearly equal thermal efficiency. Significant lowering of flame propagation rates with the lower hydrocarbons (methane, ethane, propane) of natural gas fueled spark ignition engine is observed with the corresponding increases in the average length of the combustion duration and ignition delay times. The validity of the model has been carried out with reliable data obtained under same engine setup and yields satisfactory agreement with the corresponding predicted values.

In this paper the experimental investigations relating to the performance and emission characteristics of a single cylinder spark ignition engine operating on a newly designed gasoline fuel injection system are described. This gasoline fuel injection system was operated under port and manifold injection configuration by controlling the duration of injection with an analogue based control system, which uses the information corresponding to engine speed and throttle positions. A comparison between the manually controlled fuel injection system with that of the analogue controlled version had indicated that the overall performance of the analogue base fuel injection system is better than that of the manually controlled system fuel injection.

The objective of this paper is the prediction of efficiency and NOx emission of a Spark Ignition engine based on engine design and operational parameters using artificial neural networks (ANN). This paper deals with quasi-dimensional, two-zone thermodynamic simulation of four-stroke SI engine fueled with biogas. The developed computer model has been used for the prediction of the combustion and emission characteristics of biogas in SI engines. Predicted results indicate that the presence of carbon dioxide can reduce oxides of nitrogen (NOx) emissions, but since lower cylinder pressures result, engine power and thermal efficiency are reduced. This is mainly due to the lower heating value of biogas. Using the results from this program, the effects of operational and design parameters of the engine were investigated. For real time computations in electronic control unit (ECU) an artificial neural network (ANN) model has been suggested as an alternative to the engine simulation model.

Experimental investigations relating to the comparative assessment of the performance and emission characteristics of port and manifold gasoline injection systems of a single cylinder four stroke spark ignition engine are described. These investigations have been carried out under carburettor, port injection and manifold injection modes The experiments pertaining to the injection mode were conducted for both the single and double hole injectors by optimising the injection pressure, injection timing and its duration. Optimisation of injection timing and duration was done in terms of engine crank angle by means of a newly designed crank angle selection unit in conjunction with a developed optical crank shaft encoder capable of generating pulses at one degree crank angle intervals.

The investigations relating to the evaluation of an automobile catalytic converter are reported in this paper. These investigations are aimed at arriving at a data that would pave the way for the optimization of a catalytic converter by experimental and computer simulation at steady and transient operating conditions The converter used in the present study contains Pd, Rh binary catalyst (10:1) impregnated on ultra thin ceramic substrate. Characterization of catalytic converter was done for its compositions using Inductively Coupled Argon Plasma (ICAP) and Scanning Electron Microscope (SEM). The necessary instrumentation developed, which include pre and post converter emissions, backpressure and exhaust gas temperature are described for both steady and transient conditions. The experimental setup has been designed for assessing the performance of a catalytic converter on a passenger car at different operating conditions.

Experimental investigations relating to the use of producer gas in a spark ignition engine are reported in the proposed paper. The experimental setup consists of a single cylinder diesel engine converted to operate on a spark ignition engine mode coupled to a swinging field electrical dynamometer. A downdraft closed top charcoal gasifier has been used to generate the producer gas. After cooling and cleaning, it is fed to a venturi type gas carburetor, which ensures proper mixing of gas and air before it enters the engine. Testing of the converted engine was carried out under gasoline mode at a specified compression ratio. However subsequent tests on producer gas operation were performed at different compression ratios. The significant outcome of the present investigations include the satisfactory conversion of diesel engine to a spark ignition mode for neat producer gas operation and satisfactory operation of gas carburetor designed and developed for the purpose.

Current generation of metal monolith using binary catalysts Pt/Rh (5:1) is simulated for transient temperature and conversion inside a catalytic converter during warm-up. A new concept in mass transfer on a catalytic combustion is introduced in this model for improving accuracy is known as Reynolds analogy. Design parameters and operating conditions are investigated for its influence on solid temperature and conversion of species. New patterns of precious metal loading have been investigated for metal savings and maximum conversion efficiency. Satisfactory validation of computed data was observed.

Optimization of catalytic converter related to flow improvements, cost and conversion of pollutants using computational model and computational fluid dynamics (CFD) are described in this paper. A computational model is developed for predicting the performance of Pd/Rh catalytic converter at wide range of operating conditions. An experimental investigation was done on Pd/Rh catalytic converter for validating the model. Optimization of the catalytic converter was carried out based on three parameters namely catalytic converter length, cell densities and typical metal loading. The cell densities varied from 200 cpi to 1200 cpi. The length of the catalytic converter varied from 70 mm to 180 mm. About 8 patterns were studied on Pd/Rh catalytic converter. The predicted patterns show that about 48 percent precious metal can be saved by proposed metal loading patterns.

In this paper the experimental investigations relating to the performance and emission characteristics of a single cylinder spark ignition engine operating on a newly designed gasoline fuel injection system is described. This gasoline fuel injection system was operated under port injection configuration by controlling the duration of injection with PC based control system, which uses the information corresponding to engine speed and throttle positions. A comparison between the manually controlled version had indicated that the overall performance of the PC based fuel injection system is better than that of the manually controlled system fuel injection system.

In this research, the potential of Diethyl ether (DEE) which is a renewable bio-based fuel has been identified as a supplementary oxygenated additive to improve fuel properties and combustion characteristics of biodiesel (Karanja oil methyl ester - KOME) like its high viscosity, cold starting problems and a high level of NOx emissions through an experimental investigation. The tests were conducted on a single cylinder DI diesel engine fueled with neat KOME as a base fuel and blends of 5, 10, 15 and 20% DEE on a volume basis. Some physicochemical properties of test fuels such as heating value, viscosity, specific gravity and distillation profile were determined in accordance to the ASTM standards. The results obtained from the engine tests have shown a significant reduction in NOx emissions especially for DEE addition of more than 10% on a volume basis and a little decrease in smoke of DEE blends compared with neat KOME.

The effect of variation in injection pressure and Injection timing on the performance and exhaust emission characteristics of a direct injection, naturally aspirated Diesel engine operating on Diesel and Diesel-Biodiesel Blends were studied. A three-way factorial design consisting of four levels of injection pressure (150,210, 265,320 bar), four levels of injection timing (19° btdc, 21.5° btdc, 26° btdc, and 30.5° btdc) and five different fuel types (D100, B10, B20, B40, and B60) were employed in this test. The experimental analysis shows that when operating with Linseed Oil Methyl Ester-Diesel blends, we could increase the injection pressure by about 25% over the normal value of 20MPa. The engine performance and exhaust emission characteristics of the engine operating on the ester fuels at advanced injection timing were better than when operating at increased injection pressure.

Performance of a Current generation catalytic converter using Pd/Rh (10:1) as binary catalyst impeded on an ultra thin ceramic substrate and alumina wash coat is modeled for performance prediction and parametric optimization. Kinetic rates for the catalyst are reduced after conducting series of experiments on a passenger car engine. A new concept in mass transfer coefficient is introduced for improving accuracy of the model prediction. In order to take care of the precious metal resources and to become independent of precious metal price fluctuation, a new pattern of loading of precious metal is suggested for optimum performance and metal savings about 46 percent was observed. Experimental investigations were carried out to validate the established kinetic rates over a wide range operation of the engine and for the model validation. Satisfactory agreements are observed for the model prediction and experimental results.