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Compressed Natural Gas (CNG) engine has proved itself to be worthy replacement for diesel in heavy commercial and passenger transport application all over the world. In India, infrastructure development of CNG distribution and stringent emission regulations have increased the interest shown by Original Equipment Manufacturers (OEM) to concentrate to development of CNG vehicles in every segment. Indian cities are fighting pollution due to high vehicle density and since contribution of light commercial vehicles in intra city application is significant, application of dedicated CNG vehicle has been made mandatory. This paper discusses the development of dedicated CNG engine using injection technology meeting the upcoming BS-IV norms. The primary modifications made are in the cylinder head, piston, intake and exhaust systems. The engine being developed for commercial application, the best in class fuel economy is of prime focus.

In recent years the Government of India has supported the use of Liquified Petrolium Gas (LPG) in public and private vehicles. One of the ways to reduce emission is use of alternative fuels. Among alternative fuels, LPG is one of the most promising mainly because of its low exhaust emissions. The papers about LPG used in three wheeler, cars for SI or CI converted to SI engines had been published extensively in the last two decades. The applications of LPG to bi-fuel or single fuel engines are tried widely at this time. But the extensive study of LPG for small SI single cylinder two stroke engine of three wheeler two stroke engine is not reported in depth. This paper describes development of bi-fuel (LPG/Gasoline) concept of a single air cooled 200 CC single cylinder two stroke engine for three wheeler application.

A duel fuel diesel engine is a diesel engine fitted with a dual fuel conversion kit to enable use of clean burning alternative fuel like compressed natural gas. Dual fuel engines have number of potential advantages like fuel flexibility, lower emissions, higher compression ratio, better efficiency and easy conversion of existing diesel engines without major hardware modifications. In view of energy depletion and environmental pollution, dual fuel technology has caught attention of researchers as a viable technology keeping in mind the increased availability of fuels like Compresed Natural Gas (CNG). It is an ecological friendly technology due to lower PM and smoke emissions and retains the efficiency of diesel combustion. Traditionally dual fuel technology has been popular for large engines like marine, locomotive and stationery engines. However its use for automotive engines has been limited in the past due to constraints of limited supply of alternative fuels.

Due to the well-known fact of higher thermal efficiency, diesel engines are more popular than any other fuelled prime movers. Because of this feature, the diesel engines are extensively used in almost all on road and off road applications. Power generation is another widespread application of the diesel engines. Over recent past years, stringent emission legislations have been imposed on reduction of emission parameters emitting from diesel engines. Central Pollution Control Board (CPCB) of India has proposed further reduction in emissions applicable from 2013, which are the most stringent limits in the world for this category of engines up to 75 kW. This paper deals with the strategies applied and experimentation details to meet the proposed CPCB Stage-II emission limits. The criticality increases exponentially for naturally aspirated versions. The experimental investigations are carried out on various capacities of 1.0 l to 3.25 l naturally aspirated diesel genset engines.

Small power diesel engines are most demanding product in Indian market for stationary applications like power genset, agricultural purpose etc. The upcoming 2013 CPCB emission norms for diesel genset engines below 19 kW power rating are the most stringent one in the world. There is a need not only to upgrade technologies pertinent to the latest emission norms but also to reduce the product cost. This paper presents various design strategies used to meet the desired engine performance and emission levels for development of a series of small power diesel genset engines having bore dia. ranging from 76 mm to 120 mm.

This paper is focused on the prediction of in-cylinder pressure, temperatures and engine-out NOx. One of the important factors influencing engine output parameters is the rate of heat release, which affects the in-cylinder pressure, temperature and engine out emissions. A single-zone model is formulated for prediction of heat release and in-cylinder pressure. Being a predictive model, this model does not required cylinder pressure as an input. Combustion pressure is predicted by modeling compression pressure, ignition delay, heat release, and heat loss. Required Sub-models have been obtained from the literatures. Fuel burning rate is predicted using Watson model. To retain the computational efficiency and better prediction accuracy a two-zone model has been formulated to predict NOx emissions. Flame temperatures are predicted by enthalpy balance. Thermal NO concentration is predicted by using basic Zeldovich mechanism.

Recent trends towards design of High Performance Diesel engines creating more challenges in the area of design, durability and NVH aspects of components and systems. In particular, Valvetrain system of High Speed application engines is one of the most critical and complicated dynamic system in terms of precise control of events, max. Lift, control over accelerations and vibration related issues. This can be tackled by designing the cam profile for better valve train dynamics. High frequency components and/or excessive jerks in a cam profile are important sources of cam-follower vibrations. There are various techniques of designing cam profile to achieve controlled valve train dynamic behavior at high speed operations. Present paper discuss the impact of various cam profile options designed using Polydyne, N-Harmonic and B-Spline methodologies on a field problem of cam wear for high speed engine application.

Environmental pollution is of great concern; hence the emission norms for the diesel engines are made more stringent. The purpose of this work is to develop a process to optimize the FIS parameters and select a most suitable FIS by simulation to meet the target emissions. During the combustion optimization exercise of diesel engine, different hardware combinations like injector, HPP etc are matched through testing to achieve the required performance and emissions. The process requires the real testing of the engine on engine dynamometer with various hardware combinations, which is expensive and time consuming. A simulation model of diesel FIS is constructed using ‘AVL Hydsim’. The model is validated by comparing the predicted and the experimental results. The validated model is used for further work. Critical parameters were listed based on the sensitivity analysis on the base model.

Compressed Natural Gas (CNG) is now looked upon as a leading renewable fuel for vehicles in INDIA due to mounting foreign exchange expenditure to import crude petroleum. Impending stringent emissions regulations for diesel engines, specifically exhaust particulate emissions have caused engine manufactures to once again examine the potential of alternative fuels. Much interest has centred on CNG due to its potential for low particulate and hydrocarbon based emissions and adulteration hostile nature. Significant amount of research and development work is being undertaken in INDIA to investigate various aspects of CNG utilization in different types of engines. This paper discusses the methodology for conversion of a diesel engine to dedicated CNG engine and to make the engine to meet EURO-V norms. The primary modifications are made on the piston, cylinder head, intake manifold, throttle body adaptation and exhaust system.

To meet the latest trends in internal combustion engines pertaining efficiency, emissions and durability, downsizing of the engine has become the key focus area. This paper describes about a robust, reliable and an integrated approach used in design and development of state of art high power density/ high speed engine developed from the concept, which can be adopted for passenger car and LCV application. A three-cylinder, 1.5 liter displacement diesel engine, fully balanced is being designed with an objective to produce 115kW @ 4200 rpm, delivering a specific power output over 75 kW/liter, which is at par with a contemporary class of specification in it. In the first stage, a derated version of 75 kW (50 kW/liter) with Euro-IV and Euro-V specifications is targeted aiming at smaller car and light motor vehicle segment and a prime-mover for hybrid application.

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.

Dual fuel operating strategy offers great opportunity to reduce emissions like particulate matter and NOx from compression ignition engine and use of clearer fuels like natural gas. Dual-fuel engines have number of potential advantages like fuel flexibility, lower emissions, higher compression ratio, better efficiency and easy conversion of existing diesel engines without major hardware modifications. In view of energy depletion and environmental pollution, dual-fuel technology has caught attention of researchers. It is an ecological and efficient combustion technology. This paper summarizes a review of recent research on dual-fuel technology and future scope of research. Paper also throws light on present limitations and drawbacks of dual-fuel engines and proposed methods to overcome these drawbacks. A parametric study of different engine-operating variables affecting performance of diesel-CNG dual-fuel engines vis-à-vis base diesel operation is also summarized here.

In this paper, the results obtained during the optimization of the dedicated CNG 6-Cylinder naturally aspirated engine are described with the optimization strategy. Most of the diesel engines after conversion to CNG engines are having high valve overlap leading to high HC emission along with less fuel economy and high swirl leads to reduced volumetric efficiency. These issues were examined in detail and experimentation was carried out to assess the effect of low swirl thereby resulting in high flow leading to increase in volumetric efficiency and reduced emissions. The engine variables optimized for CNG operation were the engine compression ratio, ignition timing, spark plug selection, catalytic converter loading, design of first stage regulator with improved heating circuit and second stage pressure regulators, mixer venturi size, power screw setting, and intake/ exhaust system geometry.

To meet the latest trends in Internal Combustion engines regarding efficiency, emissions and durability, an integrated approach to engine development is required. This paper describes about a Robust, Reliable and an integrated approach used in design and development of an engine for high power density which can be adopted for both Off-highway application as well as Genset application. The engine is developed to meet US - EPA Tier-III Emission Norms and MoEF (Genset Emission Norms for India formulated by Ministry of Environment and Forest) emission norms respectively. This paper discusses various technologies applied in developing this engine to achieve high power density, low exhaust emissions, and low noise and vibrations. This 4 valve per cylinder engine is created largely within a digital environment using the latest computer aided design (CAD) and computer aided engineering (CAE) techniques and simulation tools.

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.

The world is facing a twin crisis of environmental degradation and fossil fuel depletion. Alternative fuels are seems to be a promising solution for low exhaust emissions. Liquefied Petroleum Gas (LPG) is a prominent alternative fuel with well developed distributed infrastructure and increasing number of Gasoline engines are now being converted to run on LPG considering the fuel economy and low exhaust emissions. This paper describes the bi-fuel (LPG/Gasoline) concept on a single cylinder engine. Air cooled Direct Injection (DI) diesel engine converted to operate on gasoline engine with electronic ignition system and it is having feature to change the spark ignition timing w.r.t. speed. The compression ratio was also reduced suitable to SI operation. CFD analysis was performed to review and subsequently to increase the cooling capacity of the engine.

Environmental degradation is on the rise due to the increased motor vehicle population. One of the strategies adopted to curb deteriorating environmental quality is the use of alternative fuels like Ethanol, Compressed natural gas and Liquefied Petroleum Gas. Natural gas is the world's most plentiful combustible fuel, abundantly available in all the continents. This naturally occurring fuel requires little or no treatment prior to use as compared to liquid petroleum products. Natural gas is also the lowest costing fuel. The use of CNG as an automotive-fuel results in significant reduction in the level of vehicular pollutants CO, HC, NOx, SOx, Pb and PM [1, 2, 3 and 4]. Additionally, the use of CNG results in reduction in the emissions of greenhouse gases (CO2), owing to the lower Carbon-to-Hydrogen ratio of the methane (CH4), as compared to other hydrocarbon fuels [5, 6 and 7].

Performance and emission tests have to be carried out on range of engines having wide applications and varied specifications. In this context situation compels to adopt critical measures and revamp the methodologies in the area of design and development / matching of cardon shafts, rubber couplings and development of test bed systems for testing of single / two cylinder engines. Considering this need, a new strategic design approach has been formulated, which have reduced cost, loss of time and serious damages. This paper outlines a modern and practical approach used along with in-house available tools for controlling various dynamic behavioral issues involved. Redesign of shafts and couplings is done based on the comprehensive mass elastic data obtained from variety of engines. Apart from conventional torsional and bending vibration theories, FE and experimental tools are used to understand the modal behavior of engine coupled systems.

Design of an efficient cooling system for new generation engines has become a critical task, which requires to be handled optimally at the design stage itself. This approach helps in minimizing the optimization trials, saving time and cost for finalization of patterns and castings. Study of water jacket core in the engine cylinder head and block is of complex nature. Shape, size and location of transfer holes play a vital role in judging the eddies formation and hot spots. It is required to eliminate the hot spots, thus improving cooling efficiency and durability of the component. Use of CFD technique is found to be an effective design tool while dealing with such kind of complex flow problems. In this paper, effective utilization of FIRE CFD code is described for water jacket design of a modular two-cylinder diesel engine being developed from scratch.

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.