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The intensifying demand of cleaner fuelled vehicles considering current norms of BSIV and upcoming stringent norms of BSVI with low cost solutions has promoted the development of CNG and dual fuel vehicles. CNG vehicle is anticipated to discover its extensive use for environment fortification and effective deployment of energy capitals. Thus, CNG vehicles can be pretty effective in averting environment deterioration. CNG has low carbon to hydrogen ratio, this leads to very low CO2 emissions compared to gasoline and diesel vehicles. CNG engines have the potential of low NOx and particulate emissions. Natural gas vehicle development has been directed on the way to current use of direct injection and port injection with S.I. engines. Generally for low cost development, all OEMs prefer optimization of existing engines. Similarly for this project, a diesel engine was converted to S.I. engine for development of low emission CNG engine.

Air Pollution is a major concern in our country due to which Indian Government has taken a decision to move from BS-IV to BS-VI which is nearly 90% reduction in NOx and 50% in particulate matter along with addition of particulate number regulation for BS-VI in comparison to BS-IV norms in very short span of time. Vehicle manufacturers are also having the challenge to produce low cost and fuel efficient product with BS-VI solution in order to meet tightening emission regulations and increasing needs of lower fuel consumption. Detailed study is done with different approaches to meet BS-VI emission which is elaborately explained in different aspect of engine design and after treatment parameter with its pros and cons. After Treatment selection plays an important role in engine development to meet stringent emission legislations and customer demands. Strategies for BS-VI were described with the advantage and drawbacks for after treatment selection.

Engine down speeding is rapidly picking up momentum in many segment of world market. Numerous engine down speeding packages from OEM have been tailored to take advantage of the increased efficiencies associated with engine down speeding. Running engine at lower rpm has numerous advantages. The most obvious of these is reduced fuel consumption, since the engine can spend more time running within its optimum efficiency range. By down speeding, the engine is made to run at low speeds and with high torques. For the same power, the engine is operated at higher specific load- Brake Mean Effective pressure (BMEP) which results in higher efficiency and reduced fuel consumption-Brake Specific Fuel Consumption (BSFC). The reasons for increased fuel efficiency are reduced engine friction due to low piston speeds, reduced relative heat transfer and increased thermodynamic efficiency.

Exhaust gas recirculation is one important measure to achieve the Bharat Stage IV, Bharat Stage V as well as the Euro V emissions legislation. EGR is one of the most promising solutions to reduce NOx to achieve Bharat Stage IV emission norms for any high specific power engine. An emissions and performance study was conducted to explore the effects of EGR and multiple injections on particulate, NOx, and BSFC. Recent work has shown that multiple injections are effective at reducing particulate. Thus, it was of interest to examine the possibility of simultaneously reducing particulate and NOx with the combined use of EGR and multiple injections. The tests were conducted on a four cylinder four valve light duty truck engine. Tests were done at emission modes (A, B & C Modes) with EGR are variation along with different injection strategies. The fuel system used was an electronically controlled, common rail injector and supporting hardware.

Increased options and flexibility in common rail direct injection provides a great opportunity for combustion optimization using fuel and air system with proper combustion chamber configuration. This paper elaborates the experimental work conducted for combustion optimization with combinations of piston bowl, intake port swirl, injector specifications and turbo charging on a 3.8 l four valve diesel engine of LDT application equipped with common rail fuel injection system and waste gate turbo charge. In meeting the target emission norms with internal engine measures, the design of the piston bowl and the nozzle configuration perform a defining role. Through simulations the best option had been carried out parametrically investigate the influence of piston bowl geometry and nozzle characteristics on the performance of the combustion system.