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Lot of waste heat in the temperature range 350-400°C is available from I.C. engine exhaust. The same can be utilized for the operation of a triple effect absorption system which requires heat from a high temperature heat source. In this paper, the energy and exergy analysis of series flow triple effect water-lithium bromide absorption systems is presented assuming engine exhaust as a heat source. A computational model has been developed for the parametric investigation of the system. The analysis involves the determination of effects of generator and absorber temperatures on the energetic and exergetic performance of the system. The performance parameters computed are coefficient of performance, exergetic efficiency and the cooling capacity.

Supermileage vehicle is a response to fuel crisis in modern times. Delhi College of Engineering (DCE) Supermileage has evolved since five generations as an answer to this crisis. A given Briggs and Stratton engine was modified as a part of the making of the vehicle. The stock engine with a configuration of 150cc, 3.5bhp, pull start, carbureted, L head, flat combustion chamber, air cooled was modified to a configuration of 52cc, 1bhp, starter motor enabled, fuel injected, overhead, wedge shaped combustion chamber with oil cooling. This paper gives an overview of the procedure followed during the designing, analysis and manufacturing of the parts of the engine and the difficulties overcome during the same.

Presence of smoke in diesel engine exhaust is an indication of poor combustion due to several factors. Nevertheless, with an ever increasing concern for the impact of air pollution on environment, animal and plant life, vehicle exhaust emissions, particularly due to road transport, have, in recent years been subjected to increasingly stringent regulations. The environmental pollution can be controlled by utilization of clean fuel such as CNG (Compressed Natural Gas). The present work was carried out on a 7.35 kW four-stroke, twin cylinder, direct injection (DI) diesel engine which was operated in dual fuel mode with substitution of up to 75% diesel with CNG. It was observed that the substitution of CNG reduced the noise level, specific fuel consumption, NOx, however increased the unburned hydrocarbons.

Household kitchens and the food industry generate millions of tons of cooked oil residue each year. Waste oils and fats can be used as renewable fuel resources as an alternative fuel for the automobiles. Conversion of waste oils and fats to bio diesel fuel has many environmental advantages over petroleum based diesel fuel. However conversion of waste oils and fats to bio fuel poses some difficulties such as the use of toxic or caustic materials and by-product disposal. Conversion to bio fuel may also decrease the economic attractiveness of using waste oils as fuels. An alternative to the use of bio diesel is the use of waste cooking oils as a fuel. Using relatively unmodified waste cooking oils or fats eliminates the problems which were associated with toxic and caustic precursor chemicals and residual bio diesel alkalinity as the oil is used without altering its chemical properties.

Three-dimensional numerical simulations using FLUENT were performed to model the airflow over the supermileage vehicle. The purpose of the study was to design the shape of the body shell of the vehicle, powered from a self-developed electronic fuel injected 50 cc four stroke engine, to achieve low drag. The methodology focuses on an inside-out approach of optimization of body shape through computation of aerodynamic forces on a low mass vehicle. The experimental measurements were carried out to validate the results obtained from the computational model using a 1:5 scale model of the vehicle body shell in a low speed wind tunnel. Numerical solutions of pressure distribution, drag and down force are reported and compared with experimental data. The results shows a considerable reduction in drag and negative lift in the computational model, leading to improved fuel economy in comparison to Supermileage 2005 vehicle's design.

In this study some experiments were carried out to evaluate fuel consumption and exhaust emissions of carbon monoxide (CO), oxides of nitrogen (NOx)) and hydrocarbons (HC) with compressed natural gas (CNG) and gasoline in a single cylinder engine. Compressed natural gas showed 3 to 5 percent higher thermal efficiency and 15 percent lower specific fuel consumption as compared to gasoline. Also CO emissions were lower by 30-80 percent in rich zone and NOx by about 12 percent at an equivalence of 1.0. At wide open throttle CNG operation resulted in 10 to 12 percent lower power output. However, thermal efficiency and brake specific fuel consumption (bsfc) was better with CNG as compared to gasoline. Dual spark plug operation increased power output by 3 to 5 percent.

In this paper, the contribution of the various means for controlling harmful automobile emissions has been discussed. The benefits, which could accrue by use of the catalytic converter and other engine design improvements, including alternative technologies, are considered so that appropriate emission control technologies could be adapted in the near and long term future. Catalytic converter is a device with proven technology and hence it is included with greater emphasis. The oxidation type catalytic converter provides positive atmosphere to oxidize carbon monoxide and hydrocarbons along with restricting the conversion of NOx [1]*. Other technologies such as exhaust gas recirculation, fuel cell, alternative fuels and electric/hybrid vehicular technology have also been discussed in brief.

In this study experiments were carried out to evaluate performance and exhaust emissions of carbon monoxide (CO) and hydrocarbons (HC) with ethanol-gasoline blends (15E and 85E) and gasoline in a single cylinder, 4-/changing parameters like engine speed, compression ratio, air-fuel ratio and ignition timing were studied in relation to engine performance and exhaust emissions. Effect of intake air temperature on engine performance was also studied. It was found that higher power output and improved energy efficiency were possible with ethanol gasoline blends as compared to gasoline at similar air-fuel ratios. At higher compression ratios engine performance was further improved with ethanol gasoline blends. An extended lean limit was observed which was favorable to obtain lower exhaust emissions.

Analysis and evaluation of total and individual hydrocarbon components during the scavenging process is desirable for possible improvements in fuel consumptions and emissions for small two stroke gasoline engines. Experiments were carried out to analyse and understand the history of hydrocarbons near the exhaust port using a high speed electromagnetic gas sampling valve and the gas chromatography technique. The analysis showed that during the scavenging process initially the hydrocarbon concentration decreases, goes to a minimum level around bottom dead centre and increases again to its maximum level. The analysis of the composition of the individual hydrocarbons (C1 to C6) was carried out near the exhaust port and inside the cylinder. The composition of gases near the exhaust port predominantly consists of hydrocarbons having higher carbon numbers (C5 and above). The in-cylinder gases (during expansion) contain a higher proportion of hydrocarbons with lower carbon numbers.

Methanol (90% methanol + 10% gasoline) when used as a fuel in a 2-stroke spark ignition (SI) engine gave rise to abnormal combustion even at a low compression ratio. The regime of engine operation in which abnormal combustion occurs was identified and the effects of engine parameters such as mixture strength, compression ratio, ignition timing, combustion chamber geometry etc. were studied. Analysis of pressure-time histories of engine cycles when abnormal combustion occurred revealed that abnormal combustion at higher loads is similar to knocking in four-stroke engines. At light loads the nature of abnormal combustion was different. The CFR octane rating of methanol does not correlate with actual anti-knock quality in two-stroke engine combustion. Comparison with primary reference fuels indicated that the two-stroke engine has a very high severity. The hot residual gases seem to have a major role on onset of abnormal combustion.