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This paper describes the development of a computer simulation model for a single cylinder direct injection diesel engine for neat diesel operation, ethanol-diesel dual fuel operation in fumigation and dual injection mode, operating on conventional or low heat rejection version. The model which illustrates the simulation of the overall cycle consisting of compression, combustion, expansion, exhaust and intake processes also predicts the nitric oxide and soot emissions. In addition it also predicts the brake power, brake thermal efficiency, brake specific fuel consumption, maximum gas pressure and maximum gas temperature. The above model was validated using available experimental results. Subsequently the computer program was run for different operating conditions encompassing broad changes in several engine operating parameters.

Experimental investigations relating to the performance and emission characteristics under idling conditions of a three cylinder passenger car spark ignition engine operating on a conventional carburettor and a developed single point gasoline fuel injection system are described in this paper. The idling performance at different engine speeds was studied by carrying out comprehensive engine testing on a test bed in two phases. In the first phase, experiments were conducted on an engine fitted with a conventional carburettor whilst they were extended to the engine provided with a developed electronic single point fuel injection (SPI) system, whose fuel spray was directed against the direction of air flow. The injection timing of the SPI system was varied from 82 deg. before inlet valve opening (or 98 deg. before top dead center) to 42 deg. after inlet valve opening (or 26 deg. after top dead center).

This paper reviews the current research work on Homogeneous Charge Compression Ignition (HCCI) concept for diesel engines to meet future tightened emission norms. Heavy duty diesel engines are facing conflict between the goal of emission reduction and optimization of fuel consumption. In response to social demands and progressively strengthened emission regulations, diesel engines have been made cleaner through various means such as the combustion chamber, high pressure fuel injection, and turbocharger. In recent years, high pressure fuel injection has been considered as an effective method to reduce Particulate Matter (PM) by improving atomization and better air utilization, however, resulting in an increased Nitric Oxides (NOx) formation due to high temperature combustion. To fulfill future tightened emission norms, further developments on diesel engine technology and combustion improvements are required for simultaneous reduction of NOx and PM emissions as opposed to a trade-off.

Ethanol is an alternative renewable fuel produced from various agricultural products. Ethanol-diesel emulsion technique is used for the utilization of ethanol in diesel engines wherein ethanol is used without any modification. The performance, combustion and emission characteristics of a direct injection (DI) diesel engine for off-highway application were evaluated using ethanol-diesel microemulsions. The addition of ethanol to diesel fuel simultaneously decreases calorific value, kinematic viscosity and stability of fuel. Ethyl acetate was used as an additive/ingredient to keep the blends in homogeneous and stable state. Blends (D80/E13/EA07; D70/E17/EA13; D60/E23/EA17) were selected for engine experiments based on stability behavior and fuel properties. The results showed no significant power reduction in the engine operation with ethanol-diesel microemulsions.

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.

The methyl ester of karanja oil, known as biodiesel, is receiving increasing attention as an alternative fuel for diesel engine. This paper presents the results of investigations carried out in studying the fuel properties of karanja oil methyl ester (KOME) and its blend with diesel from 20% to 80% by volume and in running a DI diesel engine with these fuels. Engine tests have been carried out with the aim of obtaining performance characteristics such as Brake specific fuel consumption(BSFC), brake thermal efficiency, brake power, exhaust gas temperature, emission such as CO, UBHC, NOx, smoke opacity and combustion parameters to evaluate and compute the behavior of the diesel engine running on KOME and its blends with diesel fuel. The addition of KOME to diesel fuel has significantly reduced CO, UBHC and smoke emissions but it increases the NOx emission slightly.

In a dual fuel engine a primary fuel that is generally a gas is mixed with air, compressed and ignited by a small pilot- spray of diesel as in a diesel engine. Dual fuel engines generally suffer from the problem of lower brake power and lower peak engine cylinder pressure due to lower volumetric efficiency, although an improvement in brake specific energy consumption is observed compared to pure diesel mode. Results indicate that with an increase in percentage of CNG substitution the brake power decreases. The exhaust gas temperature and peak cylinder pressure also decrease. The rate of pressure rise is higher at lower engine speeds (1100, 1400 rev/min), although at 1700 and 2000 rev/min it is lower. The delay period throughout the engine speed shows an increasing trend. The coefficient of variation is also higher throughout the engine speeds and shows an increasing trend. The brake specific energy consumption is lower at 1100, 1400 and 1700 rev/min and at 2000 rev/min it is higher.

The increasing use of natural gas as a vehicle fuel has generated considerable research activity to characterize the performance of engines utilizing this fuel. A light duty prechamber diesel engine was run under naturally aspirated and turbocharged CNG- Diesel dual fuel mode at four engine speeds 1100, 1400, 1700 and 2000 rpm. The maximum percentage of CNG substitution continues up to the engine knock limited power. The experimental results indicate a fall in brake power under naturally aspirated CNG-Diesel dual fuel mode compared to neat diesel operation. It was due to decrease in volumetric efficiency and slower combustion. Although turbocharged dual fuel operation shows an increase in brake power as well as an improvement in brake specific energy consumption as it provides a better air/fuel mixing and improves the homogeneous natural gas/air charge.

Performance, combustion and emission characteristics relating to the use of 20% methanol and 80% gasoline in a spark ignition engine are described in this paper. The engine used for experimental purpose is a motorcycle engine of 13.4 kW (18 hp). A new online multi liquid fuel mixing system has been developed for perfect mixing and hence found to be better for investigating effects of Methanol - Gasoline blend (M20) which enhances engine performance and reduces exhaust emissions. Performance tests conducted under Throttle Body Injection (TBI) showed considerable performance improvement in power output and in thermal efficiency, as well as substantial reduction in BSFC, HC, and CO emissions than that of a conventional carbureted engine. The results of this work can contribute to improve the air pollution in the urban area.

Performance, combustion and emissions investigations relating to the use of gasoline injection in a spark ignition engine are described in this paper. The engine used for experimental purpose is a motorcycle engine of 13.4 kW (18 HP). Experimental engine test setup is designed to operate in carburetion as well as in injection mode [1]. Electronic controlled throttle body injection system is designed to operate test engine in injection mode. This paper also present the procedure used for gasoline fuel injection optimization and discussed the results obtain for minimum fuel consumption, for maximum power and for minimum brake specific fuel consumption, for optimization of the start of injection (i.e. injection delay), injection duration and injection pressure, for the entire operating range, of the research engine used for investigation.

A thermodynamic simulation model for the 4-stroke cycle of a single cylinder spark ignition engine operating on neat methanol is described in this paper. The development of the model for all the processes is illustrated. It computes the gas pressure, gas temperature and the rate of formation of nitric oxide and carbon monoxide at each crank angle using basic energy equation and reaction kinetic mechanism. A gas exchange model has been formulated by finite difference scheme to evaluate the mass flow rate through valves and the properties in the intake and exhaust systems. The validation of the above model has been carried out by comparing the predicted and experimental data at different operating conditions encompassing changes in fuel-air equivalence ratio, speed, load, spark timing and compression ratio. The special characteristics of methanol such as rapid burning rate, high power output and reduced nitric oxide emissions have been truthfully predicted by the model.

A thermodynamic cycle simulation model is described for a dual fuel open combustion chamber compression ignition engine. The model has been formulated for the compression, combustion, expansion, exhaust and intake processes. The combustion model is simulated by estimating the heat release rates due to the injected dissel fuel and the secondary fuel (biogas) supplied through the intake manifold. The injected fuel's heat release rate is computed from the preparation and burning rates, uhile that of the biogas is determined from the entrainmBnt of air and biogas mixture into the fuel spray. A finite difference scheme is employed to solve the gas exchange process for both the exhaust and intake systems. The overall comparison shous that the model satisfactorily predicted the experimental data.