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The Partially Pre-mixed Charge Compression Ignition (PCCI) combustion was experimentally and computationally investigated with retarded injection timing for mixture homogeneity and for lower emissions. PCCI combustion concept was experimentally evaluated with retarded injection timing close to TDC with high EGR levels up to 50%. The CFD analysis has carried out for mixture homogeneity with different injection pressures and timings. A 4-cylinder TCIC engine having 2valves/cylinder were selected for experiments and speed vs. torque mapped for LCV applications. A Visio technique has been used to study the in-cylinder combustion. After fine tuning of injection pressure, injection timing and EGR ratio over entire range of engine speeds and loads, a 13-mode ESC test cycle has been carried out for EURO-IV and EURO-V emissions. Experimental results shows that it is possible to meet EURO-IV emissions with combined PCCI-DI combustion concept with economical aftertreatment solution.

Homogeneous Charge Compression Ignition (HCCI) combustion concept has potential of reducing NOx and PM emissions simultaneously and it is being considered as a future technology for diesel engines to meet tightened emission norms imposing by national governments. However, HCCI is limited to a narrow band of operating region due to difficulties in controlling combustion phasing close to Top Dead Center (TDC). From literature study, Exhaust Gas Recirculation (EGR), Intake Temperature, Boost Pressure, Equivalence Ratio and Compressions ratios are considered as most critical parameters for HCCI control. The chemical kinetics study was conducted to understand the HCC combustion using N-heptane mechanism with 162 species and 732 reactions. At lower equivalence ratio (lean burn combustion) higher CO and HC emissions were observed. The combustion efficiency was poor at lower temperatures, which resulted in high HC and CO emissions with less than 10ppm NOx.

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.

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.

The paper discusses the potential of a conventional light duty indirect injection diesel engine for operation under naturally aspirated and turbocharged conditions. An exhaust gas New Garret air turbocharger with waste-gate control was used for the present investigations. The results of an extensive experimental programme using an 2.4 liter in-line four-cylinder engine are presented to predict the pressure crank angle diagram, brake power output, brake specific energy consumption, delay period, rate of pressure rise, volumetric efficiency, peak cylinder pressure, exhaust gas temperature and coefficient of variation. The paper also presents some numerical results and a comparison between computed and experimental pressure crank angle diagram for turbocharged diesel engine.

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.

A Comprehensive computer simulation model was developed for a single cylinder spark ignition engine to simulate the Compression, Combustion, Expansion, Exhaust and Intake processes including the heat losses through the cylinder walls. The gas exchange processes were simulated with the help of a finite difference scheme and a separate boundary condition was developed for the throttle action on a conventional carburetor. The model after validating with the experimental data was used to arrive at the optimum duration and lift of the intake valve corresponding to different throttle positions of the equivalent conventional engine. These optimum values were used in the design of a 3 dimensional cam. Based on this design a new variable valve timing engine (VVT) has been designed and developed. Comparison between the computed and experimental data for the VVT engine was observed to be satisfactory.

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.

This paper describes the experimental investigations on a single cylinder, two stroke spark ignition engine in the carburettor and in-cylinder injection (GDI) modes. The experiments were conducted on the engine in the carburettor mode up to 80% throttle opening and for different combinations of speed and load. The engine was modified and fitted with an in-cylinder injector in the head. Fuel was supplied through injector with the help of a high pressure DC pump. Experiments for varying speed and load were conducted under in-cylinder injection mode up to 80% throttle opening. It was observed that there is a significant reduction in BSFC, unburnt HC and CO emissions. Also, the power output of the engine has shown an improvement.

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.

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.

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.

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.

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.

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.

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.

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).